Boron-containing bicyclohexane derivatives and uses thereof

Abstract

The application relates to a boron-containing double six-membered spiro ring derivative and application thereof, and belongs to the technical field of organic optoelectronic devices. The application discloses a boron-containing double six-membered spiro ring derivative which has any one of the following general formulae: The application also simultaneously provides application of the above boron-containing double six-membered spiro ring derivative as a TADF host material.

Description

Technical Field

[0001] This invention relates to a boron-containing bis-six-membered spirocyclic derivative and its uses, belonging to the field of organic optoelectronic device technology. Background Technology

[0002] Research and applications of organic electroluminescent materials have been widely conducted in academia and industry, and a large number of high-performance organic electroluminescent materials have been developed. Thermally activated delayed fluorescence (TADF) materials are the third generation of organic light-emitting materials, following organic fluorescent and organic phosphorescent materials. Third-generation organic electroluminescent materials generally possess a small singlet-triplet energy level difference (Δ). EST Triplet excitons can be converted into singlet excitons to emit light through reverse system-reinforcement crossover (RISC). This allows for the simultaneous utilization of singlet and triplet excitons formed under electrical excitation, resulting in an internal quantum efficiency of up to 100%. Therefore, it is considered one of the promising organic light-emitting materials for future applications. However, the operating lifetime of these devices, especially blue light devices, remains an unresolved issue. Overall, the future development direction of organic electroluminescent devices will be high-efficiency, long-lifetime, and low-cost white light devices and full-color display devices, but the industrialization of this technology still faces many key challenges. Therefore, designing and finding a stable and efficient compound as a novel material for organic electroluminescent devices to overcome its shortcomings in practical applications is a key focus and future research trend in organic electroluminescent device materials research.

[0003] OLED devices and organic light-emitting diodes (OLEDs) utilize TADF (Transient Aluminum Dioxide) as a light-emitting layer in OLEDs. However, the performance of the emitting materials in traditional TADF-based OLED devices is often unsatisfactory, hindering their industrialization. In the multilayer structure of OLED devices, the chemical structure, thermal stability, photophysical properties, and quantum yield (PLQY) of the emitting layer material directly determine the device efficiency. In addition, molecular packing and charge transfer also affect device performance. Boron, due to its unique valence electron structure—with fewer valence electrons than valence orbitals and an empty p orbital—can form tetracoordinate compounds that can effectively conjugate with neighboring π systems and readily complex with Lewis bases to form tetracoordinate compounds. Introducing boron into traditional optoelectronic functional molecules often imparts unique optoelectronic properties to the entire system, which has become an important approach in the design of novel organic optoelectronic functional molecules. Due to the "insulating" effect of the P=O / S bonds in arylphosphorus / oxygen / sulfur compounds, the formation of low-energy charge-transfer states can be effectively suppressed, ensuring blue or deep blue luminescence. Simultaneously, its strong electron-withdrawing effect enables effective molecular polarization, enhancing the material's electrical transport properties and improving its quantum efficiency. Furthermore, its unique tetrahedral configuration significantly improves the material's thermal stability. Therefore, developing novel luminescent materials containing P=O / S is also of paramount importance.

[0004] The compound PSAFO has the following structural formula: It can be used as the main material for TADF light emission (OrganicElectronics95(2021)106193). Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a synthesis and application of a boron-containing bis-six-membered spirocyclic derivative.

[0006] To address the aforementioned technical problems, this invention provides a boron-containing bis-six-membered spirocyclic derivative, the compound having the following general formula:

[0007]

[0008] Wherein, Ar1 represents a C1-C30 alkyl group, a C6-C60 aryl group, or a 1- to 30-membered heteroaryl group, substituted or unsubstituted, after deuteration; or a monocyclic or polycyclic ring, specifically a C3-C60 aliphatic or aromatic ring, wherein the carbon atom may be replaced by at least one heteroatom selected from nitrogen, oxygen, and sulfur; or at least one of the following: an unsubstituted C12-C40 carbazole group and its derivative group, a substituted or unsubstituted C12-C40 diphenylamine group and its derivative group, or a C13-C40 acridine group and its derivative group; at least one or more, or all of the deuterated hydrogen atoms are deuterated (i.e., the hydrogen on Ar1 is selected to be deuterated, and at least one or more, or all of the deuterated hydrogen atoms are deuterated).

[0009] Ar2 is selected from hydrogen, deuterium, substituted or unsubstituted aryl groups, and substituted or unsubstituted heterocyclic groups containing one or more N, O and S atoms;

[0010] Ar3 and Ar4 are independently selected from any one of hydrogen, deuterium, CN, halogen, C1-C60 alkyl, C1-C60 alkoxy, C1-C60 alkylsilyl, C1-C60 alkoxysilyl, substituted or unsubstituted C6-C60 aryl, substituted or unsubstituted C1-C60 heteroaryl, substituted or unsubstituted alkenyl, substituted or unsubstituted aryl ether, substituted or unsubstituted heteroaryl ether, substituted or unsubstituted arylamine, substituted or unsubstituted heteroarylamine, substituted or unsubstituted arylsilyl, substituted or unsubstituted heteroarylsilyl, substituted or unsubstituted aryloxysilyl, substituted or unsubstituted arylacyl, substituted or unsubstituted heteroarylacyl, and substituted or unsubstituted phosphine; heteroaryl refers to a substance containing at least one heteroatom from B, N, O, S, P (=O), or Si.

[0011] In one embodiment, Ar1 is selected from any of the following structures, but is not limited to them:

[0012]

[0013] In one embodiment, Ar2 is selected from any of the following structures, but is not limited thereto:

[0014]

[0015] In one embodiment, Ar3 and Ar4 are identical to each other and are selected from any of the following structures, but are not limited thereto:

[0016]

[0017] Note: In the same structural formula, Ar3 and Ar4 are considered identical when both exist simultaneously.

[0018] In one embodiment, a boron-containing bis-six-membered spirocyclic derivative has any of the following structures, but is not limited to:

[0019]

[0020]

[0021]

[0022]

[0023]

[0024]

[0025]

[0026]

[0027] The present invention also provides the use of the above-mentioned boron-containing bis-hexacyclic spirocyclic derivatives as a host material for TADF (Temperature-Emitting Diodes). Specifically, it is used to prepare TADF organic electroluminescent devices (as the host material for the light-emitting layer in TADF organic electronic light-emitting devices).

[0028] The organic electroluminescent device of the present invention, comprising the boron-containing bis-six-membered spirocyclic derivative, includes a light-emitting layer comprising the boron-containing bis-six-membered spirocyclic derivative.

[0029] The organic electroluminescent device further includes at least one or more of the following: a substrate layer, an anode layer, a hole injection layer, a hole transport layer, an electron blocking layer, a hole blocking layer, an electron transport layer, an electron injection layer, and a cathode layer.

[0030] The beneficial technical effects of this invention are as follows:

[0031] By introducing B and P (=O or =S) units and combining them with a spirocyclic structure into the molecule, a non-planar rigid structure is formed, reducing molecular aggregation and quenching. This increases the electron transport capability of the material while ensuring fluorescence quantum efficiency, which is beneficial for constructing blue light-emitting materials with thermally excited delayed fluorescence (TADF) characteristics. The combination of electron donor (D) and electron acceptor (A) in the molecule can effectively improve the equilibrium migration of charge carriers, enhancing the luminous efficiency and lifetime of the device. The compound material described in this invention has good application effects in OLED light-emitting devices and has good industrialization prospects. Attached Figure Description

[0032] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0033] Figure 1 This is a structural diagram of an OLED device.

[0034] A: Organic light-emitting devices:

[0035] 01: Substrate, 02: Anode, 03: Hole injection layer, 04: Hole transport layer, 05: Light emission layer, 06: Electron transport layer, 07: Electron injection layer, 08: Cathode. Detailed Implementation

[0036] The present invention will be further described below with reference to specific embodiments, but the scope of protection of the present invention is not limited thereto:

[0037] Example 1: Synthesis of the parent nucleus BP-a

[0038]

[0039] Synthesis of Intermediate 1: Bis(2-bromophenyl)methane (16.3 g, 0.05 mol) was added to a dry two-necked flask. The flask was evacuated and purged with nitrogen three times (thus filling the three-necked flask with nitrogen, allowing the reaction to proceed under nitrogen protection). Dry tetrahydrofuran (90 mL) was added to the flask using a syringe, and the mixture was cooled to -80°C and stirred for 30 minutes. Then, n-butyllithium (6.73 g, 0.10 mol) was added to the flask using a syringe, and the mixture was stirred for 6 hours. Subsequently, 2,4,6-trimethyl(d9)phenyl dichloroborane (12.05 g, 0.06 mol) was added, and the mixture was cooled to -80°C and stirred for 12 hours. After the reaction was complete, the mixture was brought back to room temperature, filtered through diatomaceous earth, and washed with petroleum ether (50 mL x 3). The collected filtrate was then subjected to reduced pressure to remove the solvents (tetrahydrofuran and petroleum ether). Acetone (250 mL) was then added to the flask, heated (60 °C) to dissolve, and cooled to room temperature. The mixture was then placed in a refrigerator to cool (3 °C). After 4 hours, it was filtered, and the filter cake was collected and dried (50 °C to constant weight) to obtain intermediate 1 (11.92 g, 78%). Elemental Analysis: C, 86.56; H, 9.90; B, 3.54. HRMS (ESI, Positive) (m / z): [M] + Calcd for:C22H12D9B, 305.27, found: 305.15.

[0040] Synthesis of Intermediate 2: Intermediate 1 (6.1 g, 0.02 mol) was added to a dry two-necked flask, followed by 1,10-dibromodiphenyl sulfone (11.28 g, 0.03 mol), then anhydrous 1,4-dioxane (140 mL) was added and stirred until dissolved. KN(SiMe3)2 (14.37 g, 0.06 mol) was then added, and the mixture was evacuated and purged with nitrogen three times (thus filling the three-necked flask with nitrogen, allowing the reaction to proceed under nitrogen protection). The mixture was stirred at 80 °C for 17 hours. After the reaction was complete, the mixture was extracted with ethyl acetate (100 mL) and water (3 x 150 mL). The ethyl acetate phase was filtered and evaporated to dryness to obtain the crude product. The crude product was purified by silica gel column chromatography using petroleum ether / ethyl acetate (20 / 1, v / v) as the eluent. The resulting organic phase (i.e., all collected eluent) was evaporated to dryness to obtain pure Intermediate 2 (8.00 g, 65%). Elemental Analysis: C, 66.35; H, 5.89; B, 1.75; Br, 25.96. HRMS(ESI,Positive)(m / z):[M] + Calcd for:C34H18D9BBr2, 615.26, found: 615.23.

[0041] Synthesis of Intermediate 3: Intermediate 2 (6.15 g, 0.01 mol) was added to a dry three-necked flask. The flask was evacuated and purged with nitrogen three times (to ensure the three-necked flask was filled with nitrogen, and the reaction was carried out under nitrogen protection). Dry tetrahydrofuran (80 mL) was added to the reaction flask using a syringe, and the mixture was cooled to -80 °C and stirred for 30 minutes. Then, n-butyllithium (1.35 g, 0.02 mol) was added to the reaction flask using a syringe, and the mixture was stirred for 6 hours. Subsequently, 3-(dichlorophospho)fluorene (3.23 g, 0.012 mol) was added, the mixture was cooled to -80 °C, and stirred for 12 hours. After the reaction was completed, the mixture was brought back to room temperature, filtered with diatomaceous earth, and washed with petroleum ether (50 mL * 3). The collected filtrate was then subjected to reduced pressure to remove the solvents (tetrahydrofuran and petroleum ether). Then, 30% hydrogen peroxide (15 mL) and dichloromethane (60 mL) were added to the flask, and the mixture was stirred at room temperature for 4 hours. Extraction was performed using ethyl acetate (150 mL) and saturated sodium bicarbonate aqueous solution (150 mL * 3). The ethyl acetate phase was evaporated to dryness to obtain the crude product. The crude product was purified by silica gel column chromatography using petroleum ether / ethyl acetate (12 / 1, v / v) as the eluent. The obtained organic phase was evaporated to dryness to obtain pure intermediate 3 (4.7 g, 70%). Elemental Analysis: C, 82.50; H, 6.44; B, 1.59; O, 4.77; P, 4.63. HRMS (ESI, Positive) (m / z): [M] + Calcd for: C46H25D9BO2P, 669.61, found: 669.57.

[0042] Synthesis of BP-a: Intermediate 3 (6.69 g, 0.01 mol) was added to a dry three-necked flask, followed by glacial acetic acid (70 mL). The flask was covered with aluminum foil to protect it from light. N-bromosuccinimide (3.74 g, 0.021 mol) was then added. The mixture was heated to 60 °C and stirred for 8 hours. The mixture was then allowed to return to room temperature, and water (50 mL) was added to quench the reaction. Extraction was performed using ethyl acetate (100 mL) and saturated sodium bicarbonate solution (120 mL x 3). The ethyl acetate phase was evaporated to dryness to obtain the crude product. The crude product was recrystallized from methanol, filtered, and dried to obtain pure BP-a (7.03 g, 85%). Elemental Analysis: C, 66.78; H, 4.99; B, 1.31; Br, 19.31; O, 3.87; P, 3.74. HRMS(ESI,Positive)(m / z):[M]+Calcdfor:C46H23D9BBr2O2P, 827.41, found: 827.38.

[0043] Example 2: Synthesis of the parent nucleus BP-b

[0044]

[0045] Synthesis of Intermediate 4: Intermediate 2 (6.15 g, 0.01 mol) was added to a dry three-necked flask. The flask was evacuated and purged with nitrogen three times (to ensure the three-necked flask was filled with nitrogen, and the reaction was carried out under nitrogen protection). Dry tetrahydrofuran (80 mL) was added to the reaction flask using a syringe, and the mixture was cooled to -80 °C and stirred for 30 minutes. Then, n-butyllithium (1.35 g, 0.02 mol) was added to the reaction flask using a syringe, and the mixture was stirred for 6 hours. Subsequently, 3-(dichlorophospho)fluorene (3.23 g, 0.012 mol) was added, the mixture was cooled to -80 °C, and stirred for 12 hours. After the reaction was completed, the mixture was brought back to room temperature, filtered with diatomaceous earth, and washed with petroleum ether (50 mL * 3). The collected filtrate was then subjected to reduced pressure to remove the solvents (tetrahydrofuran and petroleum ether). Sulfur powder (4.16 g, 0.13 mol) and dichloromethane (60 mL) were then added to the flask, and the mixture was stirred at room temperature for 3 hours. The sample was filtered through diatomaceous earth, washed with ethyl acetate (150 mL), and the filtrate was evaporated to dryness to obtain the crude product. The crude product was purified by silica gel column chromatography using petroleum ether / ethyl acetate (12 / 1, v / v) as the eluent. The obtained organic phase was evaporated to dryness to obtain pure intermediate 4 (5.34 g, 78%). Elemental Analysis: C, 80.58; H, 6.32; B, 1.58; O, 2.33; P, 4.50; S, 4.65. HRMS (ESI, Positive) (m / z): [M] + Calcd for: C46H25D9BOPS, 685.68, found: 685.65.

[0046] Synthesis of BP-b: Intermediate 4 (6.86 g, 0.01 mol) was added to a dry three-necked flask, followed by glacial acetic acid (70 mL). The flask was covered with aluminum foil to protect it from light. N-bromosuccinimide (3.74 g, 0.021 mol) was then added. The mixture was heated to 60 °C and stirred for 8 hours. The mixture was then allowed to return to room temperature, and water (50 mL) was added to quench the reaction. Extraction was performed using ethyl acetate (100 mL) and saturated sodium bicarbonate solution (120 mL x 3). The ethyl acetate phase was evaporated to dryness to obtain the crude product. The crude product was recrystallized from methanol, filtered, and dried to obtain pure BP-b (7.0 g, 83%). Elemental Analysis: C, 65.48; H, 4.90; B, 1.25; Br, 18.93; O, 1.90; P, 3.66; S, 3.80. HRMS(ESI,Positive)(m / z):[M]+Calcd for: C46H23D9BBr2OPS, 843.47, found: 843.46.

[0047] Example 3: Synthesis of BP-I-2

[0048]

[0049] BP-a (1.65 g, 2 mmol), p-pyridine borosilicate (1.23 g, 6 mmol), and Pd(PPh3)4 (0.023 g, 0.02 mmol) were added to a dry three-necked flask. The mixture was evacuated and purged with nitrogen three times. K2CO3 (1 M, 0.6 mL) and 1,4-dioxane (40 mL) were added to the reaction flask using a syringe. The mixture was heated to reflux in an oil bath with stirring and the reaction was continued for 12 h. After the reaction was complete, it was cooled to room temperature, filtered through a short silica gel column, washed with ethyl acetate (100 mL), and the organic phase was evaporated to dryness (at room temperature) to obtain the crude product. The crude product was purified by silica gel column chromatography using petroleum ether / ethyl acetate (20 / 1, v / v) as the eluent. The resulting organic phase was evaporated to dryness to obtain pure BP-I-2 (1.17 g, 71%). Elemental Analysis: C, 81.65; H, 5.99; B, 1.31; N, 3.40; O, 3.88; P, 3.76. HRMS(ESI,Positive)(m / z):[M]+Calcdfor:C56H31D9BN2O2P, 823.79, found: 823.77.

[0050] Example 4: Synthesis of BP-I-3

[0051]

[0052] BP-a (2.48 g, 3 mmol), diphenylamine (1.35 g, 8 mmol), and sodium tert-butoxide (1.44 g, 15 mmol) were weighed into a 250 mL two-necked flask and dissolved thoroughly in 100 mL of anhydrous toluene. PdCl2(Amphos)2 (0.106 g, 0.15 mmol) was weighed and quickly added to the flask, which was then sealed with a rubber stopper. Nitrogen gas was bubbled through the flask for 30 min, and the mixture was stirred and heated under reflux for 9 h. After the reaction was complete, the mixture was cooled to room temperature, filtered through diatomaceous earth, washed with ethyl acetate (100 mL), and the organic phase was evaporated to dryness (at room temperature) to obtain the crude product. The crude product was purified by silica gel column chromatography using petroleum ether / ethyl acetate (18 / 1, v / v) as the eluent. The resulting organic phase was evaporated to dryness to obtain pure BP-I-3 (2.5 g, 83%). Elemental Analysis: C, 83.74; H, 6.12; B, 1.08; N, 2.79; O, 3.19; P, 3.08. HRMS(ESI,Positive)(m / z):[M]+Calcd for:C70H43D9BN2O2P, 1004.04, found: 1004.01.

[0053] Example 5: Synthesis of BP-I-4

[0054]

[0055] Weigh BP-a (2.48 g, 3 mmol), carbazole (1.34 g, 8 mmol), and potassium carbonate (2.07 g, 15 mmol) into a 250 mL two-necked flask and dissolve them thoroughly in dry DMPU (60 mL). Add cuprous iodide (0.057 g, 0.3 mmol), purge the flask with nitrogen for 10 minutes, stir, and heat under reflux for 17 h. After the reaction is complete, cool to room temperature, filter with diatomaceous earth, wash with ethyl acetate (100 mL), and evaporate the organic phase to dryness (at room temperature) to obtain the crude product. The crude product is purified by silica gel column chromatography using petroleum ether / ethyl acetate (18 / 1, v / v) as the eluent. Evaporate the organic phase to dryness to obtain pure BP-I-4 (2.4 g, 80%). Elemental Analysis: C, 84.08; H, 5.74; B, 1.08; N, 2.80; O, 3.20; P, 3.10. HRMS(ESI,Positive)(m / z):[M]+Calcd for:C70H39D9BN2O2P, 999.41, found: 999.35.

[0056] Example 6: Synthesis of BP-I-5

[0057]

[0058] BP-a (3.31 g, 4 mmol), phenothiazine (1.99 g, 10 mmol), CuI (0.076 g, 0.4 mmol), and potassium tert-butoxide (2.69 g, 24 mmol) were weighed into a 250 mL two-necked flask and dissolved thoroughly in 100 mL of anhydrous DMF. Nitrogen gas was bubbled through the flask for 30 min, and the mixture was stirred and refluxed for 12 h. After the reaction was complete, the mixture was cooled to room temperature, filtered through diatomaceous earth, and the organic phase was evaporated to dryness (at room temperature) to obtain the crude product. The crude product was purified by silica gel column chromatography using petroleum ether / ethyl acetate (16 / 1, v / v) as the eluent. The resulting organic phase was evaporated to dryness to obtain pure BP-I-5 (3.83 g, 90%). Elemental Analysis: C, 79.01; H, 5.40; B, 1.02; N, 2.63; O, 3.01; P, 2.91; S, 6.03. HRMS(ESI,Positive)(m / z):[M]+Calcd for:C70H39D9BN2O2PS2, 1064.12, found: 1064.04.

[0059] Example 6: Synthesis of BP-I-19

[0060]

[0061] Synthesis of Intermediate 5: Dichloro(4-iodophenyl)phosphine (9.12 g, 0.3 mol) and potassium carbonate (6.7 g, 0.5 mol) were weighed and dissolved completely in anhydrous acetonitrile (200 mL). Then, 2-phenylbenzoindole (5.83 g, 0.3 mol) was added to the flask, and the mixture was heated to 60 °C and stirred for 8 hours. After the reaction was complete, the mixture was cooled to room temperature and extracted with ethyl acetate (200 mL) and a saturated sodium chloride solution (200 mL x 3). The organic phase was evaporated to dryness to obtain the crude product. Petroleum ether was added to the crude product for recrystallization, and the mixture was filtered to obtain pure intermediate 5 (5.68 g, 51%). Elemental Analysis: C, 61.48; H, 3.53; Cl, ​​19.10; N, 7.55; P, 8.34. HRMS(ESI,Positive)(m / z):[M]+Calcd for:C19H13Cl2N2P, 371.20, found: 371.15.

[0062] Synthesis of Intermediate 6: The synthetic route followed that of Intermediate 3, except that the 3-(dichlorophospho)oxofluorene starting material was replaced with Intermediate 5, while other parameters remained unchanged, to obtain Intermediate 6. Elemental Analysis: C, 82.49; H, 6.40; B, 1.40; N, 3.63; O, 2.07; P, 4.01. HRMS (ESI, Positive) (m / z): [M] + Calcd for: C53H31D9BN2OP, 771.75, found: 771.70.

[0063] Synthesis of BP-c: The synthetic route follows the method of BP-a, but intermediate 3 is replaced with intermediate 6, while other parameters remain unchanged, to obtain BP-c. Elemental Analysis: C, 68.48; H, 5.09; B, 1.16; Br, 17.19; N, 3.01; O, 1.72; P, 3.33. HRMS (ESI, Positive) (m / z): [M] + Calcd for: C53H29D9BBr2N2OP, 929.55, found: 929.53.

[0064] Synthesis of BP-I-19: BP-c (7.72 g, 0.01 mol), naphthalene 1-borate (4.3 g, 0.025 mol), and Pd(dppf)₂Cl₂ (0.24 g, 0.3 mmol) were added to a dry three-necked flask. The mixture was evacuated and purged with nitrogen three times. K₂CO₃ (2 M, 3 mL) and anhydrous tetrahydrofuran (110 mL) were added to the reaction flask using a syringe. The mixture was evacuated and purged with nitrogen three times. The mixture was heated in an oil bath to 110 °C with stirring and reacted for 12 h. After the reaction was complete, it was cooled to room temperature, filtered through a short silica gel column, washed with ethyl acetate (150 mL), and the organic phase was evaporated to dryness (at room temperature) to obtain the crude product. The crude product was purified by silica gel column chromatography using petroleum ether / ethyl acetate (18 / 1, v / v) as the eluent. The resulting organic phase was evaporated to dryness to obtain pure BP-I-2 (1.17 g, 71%). Elemental Analysis: C, 85.62; H, 6.00; B, 1.06; N, 2.74; O, 1.56; P, 3.02. HRMS(ESI,Positive)(m / z):[M]+Calcd for:C73H43D9BN2OP,1024.07,found:1024.04.

[0065] Example 7: Synthesis of BP-I-120

[0066]

[0067] Synthesis of Intermediate 7: Dichloro(4-iodophenyl(d4))boron (5.78 g, 0.02 mol), cesium carbonate (9.75 g, 0.03 mol), and cuprous iodide (0.38 g, 0.002 mol) were weighed and dissolved completely in anhydrous xylene (150 mL). Carbazole (3.34 g, 0.02 mol) was then added to the flask, and the mixture was heated to 130 °C and stirred for 11 hours. After the reaction was complete, the mixture was cooled to room temperature. The mixture was filtered through diatomaceous earth, washed with ethyl acetate (200 mL), and the lower filtrate was used to remove the solvents (ethyl acetate and xylene) to obtain the crude product. Petroleum ether was added to the crude product for recrystallization, and the mixture was filtered to obtain pure intermediate 7 (6.57 g, 73%). Elemental Analysis: C, 65.91; H, 4.91; B, 3.30; Cl, ​​21.61; N, 4.27. HRMS(ESI,Positive)(m / z):[M]+Calcd for:C18H8D4BCl2N, 328.04, found: 328.04.

[0068] Synthesis of Intermediate 8: The synthetic route followed that of Intermediate 1, except that the 2,4,6-trimethyl(d9)phenyl dichloroborane starting material was replaced with Intermediate 7 (molar amount unchanged), while the remaining reactants remained the same, to obtain Intermediate 8. Elemental Analysis: C, 87.95; H, 6.19; B, 2.55; N, 3.31. HRMS (ESI, Positive) (m / z): [M] + Calcd for: C31H18D4BN, 423.36, found: 423.33.

[0069] Synthesis of Intermediate 9: The synthetic route follows the method for Intermediate 2, but the starting material of Intermediate 1 is replaced with Intermediate 8 (molar amount remains unchanged), while the remaining reactants remain the same, to obtain Intermediate 9. Elemental Analysis: C, 70.43; H, 4.40; B, 1.47; Br, 21.79; N, 1.91. HRMS (ESI, Positive) (m / z): [M] + Calcd for: C43H24D4BBr2N, 733.35, found: 733.34.

[0070] Synthesis of Intermediate 10: The synthetic route followed that of Intermediate 5, except that the dichloro(4-iodophenyl)phosphine starting material was replaced with dichloro(4-iodopyridyl)phosphine (molar amount remained unchanged), while the remaining reactants remained the same, to obtain Intermediate 10. Elemental Analysis: C, 58.09; H, 3.25; Cl, ​​19.05; N, 11.29; P, 8.32. HRMS (ESI, Positive) (m / z): [M] + Calcd for:

[0071] C18H12Cl2N3P, 372.19, found: 372.19.

[0072] Synthesis of Intermediate 11: The synthetic route follows the method for Intermediate 4, except that the 3-(dichlorophospho)oxofluorene starting material is replaced with Intermediate 10 (molar amount remains unchanged), and Intermediate 2 is replaced with Intermediate 9 (molar amount remains unchanged), while the remaining reactants remain the same, to obtain Intermediate 11. Elemental Analysis: C, 81.91; H, 4.93; B, 1.23; N, 4.78; P, 3.52; S, 3.64. HRMS (ESI, Positive) (m / z): [M] + Calcd for: C60H35D4BN3PS, 879.86, found: 372.19.

[0073] Synthesis of BP-d: The synthetic route follows the method of BP-a, except that intermediate 3 is replaced with intermediate 11 (molar amount remains the same), while the other raw materials remain unchanged, to obtain BP-d. Elemental Analysis: C, 69.45; H, 3.98; B, 1.04; Br, 15.40; N, 4.05; P, 2.98; S, 3.09. HRMS (ESI, Positive) (m / z): [M] + Calcd for: C60H33D4BBr2N3PS, 1037.65, found: 1037.64.

[0074] Synthesis of BP-II-120: The synthetic route followed the method of BP-I-5, replacing BP-a with BP-d (molar amounts unchanged), and phenothiazine with phenotoxazine (molar amounts unchanged), while keeping the other starting materials unchanged, to obtain BP-II-120. Elemental Analysis: C, 81.22; H, 4.62; B, 0.87; N, 5.64; O, 2.58; P, 2.49; S, 2.58. HRMS (ESI, Positive) (m / z): [M] + Calcd for: C84H49D4BN5O2PS, 1242.25, found: 1242.19.

[0075] Comparative Example 1: Synthesis of the comparative compound CA

[0076]

[0077] Synthesis of intermediate C-1: Di(4-bromophenyl)amine (6.54 g, 0.02 mol), potassium carbonate (5.52 g, 0.04 mol), and cuprous iodide (0.38 g, 0.002 mol) were weighed and dissolved completely in anhydrous N,N-dimethylformamide (100 mL). Then, 2-iodo-1,3,5-trimethyl(d9)benzene (7.65 g, 0.03 mol) was added to the flask, and the mixture was heated to 130 °C and stirred for 16 hours. After the reaction was complete, the mixture was cooled to room temperature. The mixture was filtered through diatomaceous earth, washed with ethyl acetate (200 mL), and the lower filtrate was used to remove the solvent to obtain the crude product. Petroleum ether was added to the crude product for recrystallization, and the mixture was filtered to obtain pure intermediate C-1 (6.45 g, 71%). Elemental Analysis: C, 55.53; H, 6.21; Br, 35.18; N, 3.08. HRMS(ESI,Positive)(m / z):[M]+Calcdfor:C21H10D9Br2N, 454.25, found: 454.25.

[0078] Synthesis of intermediate C-2: Intermediate C-1 (4.54 g, 0.01 mol) was dissolved in anhydrous THF (80 mL) and added to a dry single-necked flask. The mixture was cooled to -78 °C, and n-BuLi (0.76 g, 0.012 mol) was added dropwise. The mixture was kept at this temperature for 1 hour. 10,10-Dimethylanthrone (4 g, 0.018 mol) was dissolved in anhydrous tetrahydrofuran (60 mL) and added to the mixture. The reaction was carried out for 12 hours. The mixture was extracted with dichloromethane (200 mL) and water (200 mL * 3). The organic phase was evaporated to dryness to obtain the crude product. The crude product was recrystallized from petroleum ether, filtered, and dried to obtain pure intermediate C-2 (3.92 g, 58%). Elemental Analysis: C, 65.69; H, 6.26; Br, 23.62; N, 2.07; O, 2.36. HRMS(ESI,Positive)(m / z):[M]+Calcd for:C37H24D9Br2NO, 676.54, found: 676.54.

[0079] Synthesis of intermediate C-3: Intermediate C-2 (1.35 g, 0.002 mol) was weighed into a three-necked flask, followed by the addition of glacial acetic acid (20 mL) and reflux for 2 hours. Then, 2 mL of concentrated hydrochloric acid was added until a solid precipitate formed. The precipitate was filtered, washed with petroleum ether, and dried to obtain intermediate C-3 (1.19 g, 90%). Elemental Analysis: C, 67.49; H, 6.12; Br, 24.27; N, 2.13. HRMS (ESI, Positive) (m / z): [M] + Calcd for: C37H22D9Br2N, 658.52, found: 658.52.

[0080] Synthesis of CA: The synthetic route followed the method of BP-I-19, replacing the BP-c starting material with intermediate C-3 (molar amounts remained unchanged), while keeping the other starting materials the same, to obtain CA. Elemental Analysis: C, 90.91; H, 7.23; N, 1.85. HRMS (ESI, Positive) (m / z): [M] + Calcd for: C57H36D9N, 753.05, found: 753.03.

[0081] Comparative Example 2: Synthesis of the comparative compound CB

[0082]

[0083] Synthesis of intermediate C-4: The synthetic route followed the method for intermediate 1, except that the 2,4,6-trimethyl(d9)phenyl dichloroborane starting material was replaced with intermediate 5 (molar amounts remained unchanged), while the amounts of other starting materials remained the same, to obtain intermediate C-4. Elemental Analysis: C, 82.39; H, 4.97; N, 6.00; P, 6.64. HRMS (ESI, Positive) (m / z): [M] + Calcd for: C32H23N2P, 466.52, found: 466.50.

[0084] Synthesis of intermediate C-5: The synthetic route follows the method for intermediate 2, but the starting material of intermediate 1 is replaced with intermediate C-4 (molar amounts remain unchanged), while the amounts of other starting materials remain the same, to obtain intermediate C-5. Elemental Analysis: C, 68.06; H, 3.76; Br, 20.58; N, 3.61; P, 3.99. HRMS (ESI, Positive) (m / z): [M] + Calcd for: C44H29Br2N2P, 776.51, found: 776.51.

[0085] Synthesis of intermediate C-6: Intermediate C-5 (7.76 g, 0.01 mol), 30% hydrogen peroxide (25 mL), and dichloromethane (100 mL) were added to a three-necked flask and stirred at room temperature for 4 hours. Extraction was performed using ethyl acetate (200 mL) and saturated sodium bicarbonate aqueous solution (200 mL x 3). The ethyl acetate phase was evaporated to dryness to obtain the crude product. The crude product was purified by silica gel column chromatography using petroleum ether / ethyl acetate (12 / 1) as the eluent. The obtained organic phase was evaporated to dryness to obtain pure intermediate C-6 (6.57 g, 83%). Elemental Analysis: C, 66.68; H, 3.69; Br, 20.16; N, 3.53; O, 2.02; P, 3.91. HRMS(ESI,Positive)(m / z):[M]+Calcd for:C44H29Br2N2OP, 792.51, found: 792.50.

[0086] Synthesis of CB: The synthetic route followed the method of BP-I-19, replacing the BP-c starting material with intermediate C-6 (molar amounts remained unchanged), while keeping the other starting materials the same, to obtain CB. Elemental Analysis: C, 86.66; H, 4.89; N, 3.16; O, 1.80; P, 3.49. HRMS (ESI, Positive) (m / z): [M] + Calcd for: C64H43N2OP, 887.03, found: 886.97.

[0087] Comparative Example 3: Synthesis of the comparative compound CC

[0088]

[0089] Synthesis of intermediate C-7: The synthetic route followed the method for intermediate C-1, except that the di(4-bromophenyl)amine starting material was replaced with di(4-bromophenyl)borane (molar amounts remained unchanged), while the other starting materials remained the same, to obtain intermediate C-7. Elemental Analysis: C, 55.92; H, 6.25; B, 2.40; Br, 35.43. HRMS (ESI, Positive) (m / z): [M] + Calcd for:

[0090] C21H10D9BBr2, 451.06, found: 451.00.

[0091] Synthesis of intermediate C-8: The synthetic route followed the method for intermediate C-2, but the starting material of intermediate C-1 was replaced with intermediate C-7 (molar amount remained the same), and the starting material of 10,10-dimethylanthrone was replaced with benzophenone (molar amount remained the same), while other starting materials remained unchanged, to obtain intermediate C-8. Elemental Analysis: C, 64.49; H, 6.05; B, 1.71; Br, 25.24; O, 2.53. HRMS (ESI, Positive) (m / z): [M] + Calcd for: C34H20D9BBr2O, 633.28, found: 633.26.

[0092] Synthesis of intermediate C-9: The synthetic route follows the method for intermediate C-3, but intermediate C-2 is replaced with intermediate C-8 (molar amounts remain unchanged), while other raw materials remain the same, to obtain intermediate C-9. Elemental Analysis: C, 66.37; H, 5.90; B, 1.76; Br, 25.97. HRMS (ESI, Positive) (m / z): [M] + Calcd for: C34H18D9BBr2, 615.26, found: 615.19.

[0093] Synthesis of CC: The synthetic route follows the method of CB, replacing intermediate C-6 with intermediate C-9 (molar amounts remain unchanged), while keeping other raw materials the same, to obtain CC. Elemental Analysis: C, 91.38; H, 7.10; B, 1.52. HRMS (ESI, Positive) (m / z): [M] + Calcd for: C54H32D9B, 709.79, found: 709.70.

[0094] The compounds of the present invention can be used as the host of the luminescent layer or as doping materials. The thermal properties, triplet energy levels and cyclic voltammetric stability of the compounds BP-I-1, BP-I-3, BP-I-4, BP-I-5, BP-I-10, BP-I-16 of the present invention and the comparative compounds CA, CB and CC were determined.

[0095] In OLED devices, it is generally believed that the transport of charge carriers involves repeated redox reactions of molecules. Therefore, the electrochemical properties of OLED materials are an important factor affecting device stability: (1) the electrochemical instability of unipolar materials is one of the essential reasons for device degradation; (2) the high electrochemical stability of bipolar materials helps to improve device stability, but does not necessarily guarantee high device stability; (3) the influence of the stability of the molecular structure of materials on device stability and the intrinsic decay mechanism of devices still need to be studied in depth.

[0096] Note: The thermal properties, triplet energy levels, and cyclic voltammetric stability of the material can be determined by referring to the published literature: Materials 2015, 8(12), 8793-8803, Thermochimica Acta 540(2012) 1-6, CHEMICAL SOCIETY REVIEWS 2013, 42(3), 845-856, and JOURNAL OF PHYSICAL CHEMISTRY, 1993, 97(24), 6564-6572. The test results are shown in Table 1 below:

[0097] Table 1

[0098]

[0099]

[0100] As can be seen from the data in the table above, the compounds of the present invention have high thermal stability and triplet energy levels, which improves the efficiency and lifetime of OLED devices using the compounds of the present invention as the main material.

[0101] The following detailed description of the application effects of the materials synthesized in this invention on OLED devices is provided through device embodiments and comparative examples. The fabrication processes of the devices are identical, and the same substrate and electrode materials are used, with consistent electrode film thicknesses. The only difference is that some adjustments were made to some of the materials used in the devices.

[0102] Device Example 1: OLED devices can be prepared using the boron-containing double six-membered spirocyclic derivative obtained according to the present invention, referring to the method of the published patent CN 106831745 A.

[0103] The OLED device (i.e., device A) is as follows: Figure 1 The device comprises, from bottom to top, a substrate 01, an anode 02, a hole injection layer 03, a hole transport layer 04, a light-emitting layer 05, an electron transport layer 06, an electron injection layer 07, and a cathode 08, which are stacked sequentially. The substrate 01 and the anode 02 are integrally fabricated. When the device is in operation, an external current is applied to the anode 02 and the cathode 08.

[0104] The anode 02 is made of indium tin oxide; the hole injection layer 03 is made of HI; the hole transport layer 04 is made of HT; the light-emitting layer 05 is composed of a host and a guest in a specific ratio, the host material is a boron-containing bis-six-membered spirocyclic derivative prepared in this invention, and the guest material is BD; the electron transport layer 06 is made of ET; the electron injection layer 07 is made of EI; and the cathode 08 is made of aluminum.

[0105] The transparent glass substrate 01 is made of transparent material. The ITO anode layer 02 (film thickness is 100nm) is washed by successively performing alkaline washing, pure water washing, drying, and then ultraviolet-ozone washing to remove organic residues on the surface of the transparent ITO.

[0106] After the above washing process, HI was deposited on the ITO anode layer 02 using a vacuum evaporation apparatus, with a film thickness of 10 nm. This organic material was used as the hole injection layer 03.

[0107] Next, a 60nm thick HT layer was deposited as the hole transport layer 04.

[0108] After the hole transport material is deposited, the light-emitting layer 05 of the OLED light-emitting device is fabricated. Its structure includes the compound BP-I-1 of the present invention as the main material and BD as the doping material, with a doping ratio of 7% by weight and a film thickness of 25nm.

[0109] Following the aforementioned light-emitting layer 05, an electron transport layer material of ET is further vacuum-deposited. The vacuum-deposited film of this material has a thickness of 28 nm, and this layer is the electron transport layer 06.

[0110] On electron transport layer 06, EI material is deposited by vacuum evaporation device to form an EI layer with a film thickness of 1nm. This layer is electron injection layer 07.

[0111] An 80 nm thick aluminum (Al) layer is fabricated on the electron injection layer 07 using a vacuum evaporation apparatus. This layer is used for the cathode reflective electrode layer 08. The material structures of each layer are shown below:

[0112]

[0113] Device Example 2: The difference between Device Example 2 and Example 1 is that BP-I-1 in the light-emitting layer 05 of the OLED light-emitting device is changed to BP-I-3.

[0114] Device Example 3: The difference between Device Example 3 and Example 1 is that BP-I-1 in the light-emitting layer 05 of the OLED light-emitting device is changed to BP-II-4.

[0115] Device Example 4: The difference between Device Example 4 and Example 1 is that BP-I-1 in the light-emitting layer 05 of the OLED light-emitting device is changed to BP-I-5.

[0116] Device Example 5: Device Example 5 differs from Example 1 in that BP-I-1 in the emitting layer 05 of the OLED light-emitting device is changed to BP-II-10.

[0117] Device Example 6: The difference between Device Example 6 and Example 1 is that BP-I-1 in the light-emitting layer 05 of the OLED light-emitting device is changed to BP-I-16.

[0118] Device Example 7: Device Example 7 differs from Example 1 in that BP-I-1 in the emitting layer 05 of the OLED light-emitting device is changed to BP-I-73.

[0119] Device Example 8: Device Example 8 differs from Example 1 in that BP-I-1 in the emitting layer 05 of the OLED light-emitting device is changed to BP-I-90.

[0120] Device Example 9: The difference between Device Example 9 and Example 1 is that BP-I-1 in the light-emitting layer 05 of the OLED light-emitting device is changed to BP-II-90.

[0121] Device Example 10: Device Example 10 differs from Example 1 in that BP-I-1 in the emitting layer 05 of the OLED light-emitting device is changed to BP-II-117.

[0122] Device Comparison Example 1: The difference between Example 1 and Example 2 is that BP-I-1 in the light-emitting layer 05 of the OLED light-emitting device is changed to CA.

[0123] Device Comparison Example 2: The difference between Example 1 and Example 2 is that BP-I-1 in the light-emitting layer 05 of the OLED light-emitting device is replaced with CB.

[0124] Device Comparison Example 3: The difference between Example 1 and Example 2 is that BP-I-1 in the light-emitting layer 05 of the OLED light-emitting device is changed to CC.

[0125] Table 2 shows the details of each functional layer in Device Examples 1-10 and Device Comparative Examples 1-3:

[0126] Table 2

[0127]

[0128]

[0129] Table 3

[0130]

[0131] As can be seen from the results of devices 1-10 in Table 3, the compound described in this invention, when used as the main material in the fabrication of OLED light-emitting devices, can achieve excellent device performance. The current efficiency, external quantum efficiency, and device lifetime are also significantly improved (compared to comparative devices). The compound described in this invention has good application effects in OLED light-emitting devices and shows promising industrialization prospects.

[0132] Finally, it should be noted that the above examples are merely some specific embodiments of the present invention. Obviously, the present invention is not limited to the above embodiments and many variations are possible. All variations that can be directly derived or conceived by those skilled in the art from the disclosure of the present invention should be considered within the scope of protection of the present invention.

Claims

1. Boron-containing derivatives of the bicyclohexane class, characterized in that having any one of the following structural formulae: 、 、 、 、 、 。 2. Use of boron-containing bis-hexacyclic spiro derivatives according to claim 1, characterized by the fact that: as a TADF host material.

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