An organic compound based on boron-nitrogen fused rings and an organic electroluminescent device prepared therefrom

Abstract

The present invention discloses an organic compound based on a boron-nitrogen fused ring and an organic electroluminescent device prepared therefrom, belonging to the technical field of semiconductors. The structure of the organic compound of the present invention is shown in general formula (1). By introducing substituent groups at specific positions on the boron-nitrogen fused ring parent nucleus, the compound has a narrow full width at half maximum, a high fluorescence quantum yield, a relatively high radiative transition rate, a suitable emission color, and suitable HOMO and LUMO energy levels, and can be used as a green light doping material for the light-emitting layer of an organic electroluminescent device, thereby improving the color purity and efficiency of the device.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and particularly to a boron-nitrogen fused-ring organic compound as an OLED doping material and an organic electroluminescent device containing the same. Background Art

[0002] Limited by early technologies, traditional fluorescent doping materials can only utilize 25% of singlet excitons formed by electrical excitation for luminescence, resulting in a relatively low internal quantum efficiency of the device (up to 25% at most), and the external quantum efficiency is generally lower than 5%, showing a significant gap compared with the efficiency of phosphorescent devices. Due to the strong spin-orbit coupling of heavy atom centers, phosphorescent materials can enhance intersystem crossing, effectively utilize both singlet excitons and triplet excitons formed by electrical excitation for luminescence, and achieve an internal quantum efficiency of 100% for the device. However, most phosphorescent materials are expensive, have poor material stability, poor color purity, and serious efficiency roll-off of the device, which limit their application in OLEDs.

[0003] With the advent of the 5G era, higher requirements are put forward for the color rendering standard. In addition to being efficient and stable, luminescent materials also require a narrower full width at half maximum to improve the color purity of device luminescence. Fluorescent doping materials can achieve high fluorescence quantum and narrow full width at half maximum through molecular engineering. Breakthroughs have been achieved in blue fluorescent doping materials, and the full width at half maximum of boron-based materials can be reduced to less than 30 nm. In the green light region, which is more sensitive to the human eye, research mainly focuses on phosphorescent doping materials, but it is difficult to narrow their emission peak shape through simple methods. Therefore, it is of great significance to study highly efficient green fluorescent doping materials with a narrow full width at half maximum to meet higher color rendering standards.

[0004] In addition, the TADF sensitized fluorescence technology (TSF) combines a TADF material with a fluorescent doping material. Using the TADF material as an exciton sensitization medium, triplet excitons formed by electrical excitation are converted into singlet excitons, and the energy is transferred to the fluorescent doping material through long-range energy transfer of singlet excitons, which can also achieve an internal quantum efficiency of 100% for the device. This technology can make up for the deficiency of the exciton utilization rate of fluorescent doping materials and effectively utilize the characteristics of high fluorescence quantum yield, high device stability, high color purity, and low cost of fluorescent doping materials, showing broad prospects in the application of OLEDs.

[0005] Boron-based compounds with resonance structures are more likely to achieve narrow full-width at half-maximum (FWHM) luminescence. When such materials are applied to thermally activated delayed fluorescence (TADF) sensitized fluorescence technology, devices with high efficiency and narrow FWHM emission can be fabricated. For example, in CN 107507921 A and CN110492006 A, a luminescent layer combination technology is disclosed, which uses a TADF material with a singlet-triplet energy gap less than or equal to 0.2 eV as the host and a boron-containing material as the dopant; in CN110492005A and CN 110492009A, a luminescent layer combination scheme with an exciplex as the host and a boron-containing material as the dopant is disclosed; both can achieve efficiency comparable to phosphorescence and a relatively narrow FWHM. Therefore, developing TADF sensitized fluorescence technology based on narrow FWHM boron-based luminescent materials has unique advantages and strong potential in meeting the BT.2020 display standards. Summary of the Invention

[0006] In view of the above problems existing in the prior art, the present invention provides an organic compound based on a boron-nitrogen fused ring and an organic electroluminescent device prepared therefrom. By introducing specific substituents at specific positions of the boron-nitrogen fused ring nucleus, the compound of the present invention can adjust the light color to the green region, and endow the compound with a narrow FWHM, a high fluorescence quantum yield, a relatively high radiative transition rate, and appropriate HOMO and LUMO energy levels, and can be used as a green light doping material for the luminescent layer of an organic electroluminescent device, thereby improving the color purity and lifespan of the device.

[0007] The technical solution of the present invention is as follows:

[0008] An organic compound based on a boron-nitrogen fused ring, the structure of the organic compound based on a boron-nitrogen fused ring is shown in general formula (1):

[0009]

[0010]

[0011] In general formula (1), Z1 and Z2 each independently represent C-R1; two adjacent Z2s can also be connected into a ring through a C-C bond; here, adjacent means the two Z2s with the closest distance;

[0012] X1 and X2 each independently represent a single bond, O, S, Se, Si(R1)2 or C(R1)2;

[0013] L represents a substituted or unsubstituted C6-C 30 arylene, or a substituted or unsubstituted C3-C 30 heteroarylene, n represents 0 or 1; R2 represents a structure shown in general formula (2) or general formula (3):

[0014]

[0015] In General Formula (2) and General Formula (3), Z3-Z5 each occurrence is the same or different and represents C-R1 or N; in General Formula (2), two adjacent Z4s can also be connected into a ring through a C-C bond; in General Formula (3), at least one Z5 represents N;

[0016] R1 each occurrence is the same or different and represents H, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted C1-C 10 alkyl group, a substituted amino group, a substituted or unsubstituted C6-C 30 aryl group, a substituted or unsubstituted C3-C 30 heteroaryl group, and adjacent R1s can also be connected into a ring;

[0017] The substituents of the "substituted or unsubstituted" above-mentioned groups are each independently selected from a deuterium atom, a halogen atom, a cyano group, a C1-C 10 alkyl group, a C3-C 10 cycloalkyl group, a C6-C 30 aryl group, a C2-C 30 heteroaryl group, one or more of them;

[0018] The heteroatoms in the heteroaryl group are each independently selected from one or more of oxygen, sulfur, and nitrogen atoms.

[0019] Preferably, General Formula (2) is represented by the following structure:

[0020]

[0021] General Formula (3) is represented by the following structure:

[0022]

[0023] R1 each occurrence is the same or different and represents H, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted C1-C 10 alkyl group, a substituted amino group, a substituted or unsubstituted C6-C 30 aryl group, a substituted or unsubstituted C3-C 30 heteroaryl group, one of them.

[0024] Preferably, the structure of the organic compound is shown as any one of General Formula (4) to General Formula (9):

[0025]

[0026]

[0027] In General Formula (4) - General Formula (9), the meanings of Z1-Z5, X1, and X2 are the same as those defined above.

[0028] Further preferably, R1 is represented by one of H, deuterium atom, cyano group, fluorine atom, adamantyl group, methyl group, trifluoromethyl group, ethyl group, isopropyl group, isobutyl group, tert-butyl group, cyclopentyl group, methyl-substituted cyclopentyl group, cyclohexyl group, phenyl group, deuterated phenyl group, biphenyl group, deuterated biphenyl group, terphenyl group, diphenyl ether group, methyl-substituted diphenyl ether group, naphthyl group, anthracenyl group, phenanthryl group, pyridyl group, phenyl-substituted pyridyl group, quinolinyl group, furyl group, thienyl group, benzofuryl group, dibenzofuryl group, dibenzothienyl group, carbazolyl group, N-phenylcarbazolyl group, 9,9-dimethylfluorenyl group, phenyl-substituted amino group, tert-butylbenzene-substituted amino group, tert-butyl-substituted dibenzofuryl group, methyl-substituted phenyl group, ethyl-substituted phenyl group, isopropyl-substituted phenyl group, tert-butyl-substituted phenyl group, methyl-substituted biphenyl group, ethyl-substituted biphenyl group, isopropyl-substituted biphenyl group, tert-butyl-substituted biphenyl group, phenyl-substituted tert-butyl group, xanthenone group, phenyl-substituted triazine group.

[0029] Further preferably, at most 3 of Z3 are represented by N; preferably, X1 and X2 are the same.

[0030] Further preferably, the structure of the organic compound is represented by any one of general formulas (5) to (8).

[0031] In a preferred embodiment, the specific structural formula of the organic compound is any one of the following structures:

[0032]

[0033]

[0034]

[0035]

[0036]

[0037]

[0038]

[0039]

[0040]

[0041]

[0042]

[0043]

[0044]

[0045]

[0046]

[0047]

[0048]

[0049] An organic electroluminescent device includes a cathode and an anode, and an organic light-emitting functional layer therebetween. The organic light-emitting functional layer includes a light-emitting layer, and the light-emitting layer contains the organic compound based on boron-nitrogen fused rings.

[0050] In a preferred embodiment, the light-emitting layer contains a host material and a dopant material, and the dopant material contains the organic compound based on boron-nitrogen fused rings.

[0051] More preferably, the light-emitting layer contains a first host material, a second host material and a dopant material. At least one of the first host material and the second host material is a TADF material, and the dopant material is the organic compound based on boron-nitrogen fused rings.

[0052] The beneficial technical effects of the present invention are as follows:

[0053] (1) The compound of the present invention can be used as a dopant material for the light-emitting layer material in an OLED device, and can emit green fluorescence under the action of an electric field, and can be applied to the fields of OLED lighting or OLED display;

[0054] (2) By introducing specific groups at specific positions in the compound of the present invention, the light color can be adjusted to the green light region, the resonance intensity of the structure itself can be enhanced, and the light-emitting efficiency of the material and the device efficiency can be improved;

[0055] (3) The compound of the present invention has a high fluorescence quantum efficiency as a dopant material, and the fluorescence quantum efficiency of the material is close to 100%;

[0056] (4) As a dopant material, the compound of the present invention introduces a TADF sensitizer as the second host, which can effectively improve the device efficiency;

[0057] (5) The spectral FWHM of the compound of the present invention is narrow, which can effectively improve the device color gamut and the light-emitting efficiency of the device;

[0058] (6) The evaporation decomposition temperature of the compound of the present invention is high, which can inhibit the evaporation decomposition of the material and effectively improve the device life.

[0059] (7) The radiative transition rate of the compound of the present invention is relatively high, which can effectively improve the lifespan of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 It is a schematic structural diagram of the materials listed in the present invention applied to an OLED device;

[0061] Among them, 1 is a transparent substrate layer, 2 is an anode layer, 3 is a hole injection layer, 4 is a hole transport layer, 5 is an electron blocking layer, 6 is a light-emitting layer, 7 is a hole blocking layer, 8 is an electron transport layer, 9 is an electron injection layer, and 10 is a cathode layer. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0062] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other. The present invention will be further described below in conjunction with the drawings and specific embodiments, but it is not a limitation of the present invention.

[0063] The following embodiments are intended to better explain the present invention, but the scope of the present invention is not limited thereto.

[0064] The raw materials involved in the synthesis examples of the present invention can all be purchased from the market or prepared by conventional preparation methods in the art;

[0065] Synthesis of Compound 33 in Example 1:

[0066] (1) Preparation of Intermediate c-1:

[0067]

[0068] Under nitrogen protection, 0.90 mmol of raw material A-1, 2.70 mmol of raw material B-1, 5.20 mmol of K2CO3 and 20 mL of DMF were added to a three-necked flask, and then heated to 110 °C. After stirring for 3 hours, the reaction mixture was cooled to room temperature, and the reaction mixture was poured into a large amount of MeOH to produce a precipitate. After filtration, the obtained solid was washed with MeOH, and the obtained filtrate was evaporated in vacuo. The obtained residue was purified by silica gel column chromatography (eluent: PE:DCM = 5:1) to obtain Intermediate a-1. LC-MS: Measured value: 702.85 ([M+H] + )), theoretical value: 701.92.

[0069] Dissolve 1.0 mmol of intermediate a-1 in 250 ml of acetic acid, add 1.5 mmol of HBr solution simultaneously, heat to reflux for 1 hour, monitor the reaction progress by TLC. After the reaction is complete, add saturated NaHCO3 solution to neutralize the reaction, extract the reaction solution with DCM, combine the organic phases, evaporate the solvent to obtain the crude product, and recrystallize with ethanol to obtain intermediate b-1. LC-MS: Measured value: 674.92 ([M+H] + ), theoretical value: 673.88.

[0070] Under nitrogen protection, in a three-necked flask, add 10 mmol of intermediate b-1, 0.2 mmol of Pd(OAc)2, 1.38 g of K2CO3, and add 150 ml of toluene. Heat to 110 °C and reflux for 12 hours. After the reaction is complete, add water to quench the reaction, extract the organic phase with dichloromethane at the same time, combine the organic phases, dry with anhydrous magnesium sulfate, filter, evaporate the solvent to obtain the crude product, and purify by silica gel column chromatography (eluent: PE:DCM = 5:1) to obtain intermediate c-1. LC-MS: Measured value: 515.09 ([M+H] + ), theoretical value: 514.03.

[0071] (2) Synthesis of compound 33:

[0072]

[0073] Under nitrogen protection, in a three-necked flask, add 11.0 mmol of intermediate c-1, 10.0 mmol of raw material C-1, 16.0 mmol of K2CO3 and 140 ml of DMSO. After adding, stir evenly, then add 1.0 mmol of CuI and 1.0 mmol of trans-cyclohexanediamine. After stirring evenly, heat to 140 °C and react overnight (about 10 hours). Confirm the reaction is complete by HPLC detection. Filter through diatomaceous earth, evaporate the solvent under reduced pressure, add 11 mL of ethyl acetate and extract twice, wash with hydrochloric acid, then combine the ethyl acetate layers, evaporate the solvent, and slurry with heptane / toluene (5 / 1) to obtain intermediate d-1. LC-MS: Measured value: 714.23 ([M+H] + ), theoretical value: 713.30.

[0074] In a three-necked flask, under nitrogen protection, 2.20 mmol of boron triiodide and 1.10 mmol of intermediate d-1 were dissolved in 30 mL of 1,2,4-trichlorobenzene. After stirring at 180 °C for 20 hours, the reaction mixture was diluted with dichloromethane (50 mL), and 100 mL of sodium phosphate buffer solution with pH = 6 was added at 0 °C. The aqueous layer was separated and the organic layer was extracted with dichloromethane (100 mL, three times). The crude product was purified by silica gel column chromatography (eluent: hexane / CH2Cl2 = 5 / 1) to obtain the target compound 33.

[0075] Example 2 Synthesis of Compound 47:

[0076] (1) Preparation of Intermediate f-2:

[0077]

[0078] In a three-necked flask, 2.3 g of NaH and 60 ml of DMSO were added. Then, 10.1 g of 2-bromophenol was slowly added to the stirred mixture. After the evolution of hydrogen stopped, 6.4 g of raw material A-2 was added, and the reaction was heated at 90 °C for 90 minutes under nitrogen protection; after natural cooling to room temperature, the reaction mixture was poured into cold water and extracted with ethyl acetate. Then, the organic layer was dried over anhydrous sodium sulfate, filtered, and concentrated in vacuo. The obtained crude product was recrystallized from ethanol to obtain intermediate a-2. LC-MS: Measured value: 542.88 ([M+H] + ), theoretical value: 541.85.

[0079] In a three-necked flask, 47.4 g of SnCl2·H2O and 200 ml of ethanol were added. The ethanol solution of intermediate a-2 was slowly dropped into the solution, and the reaction was heated at 70 °C for 40 minutes under nitrogen flow; after natural cooling to room temperature, the reaction mixture was poured into water and neutralized by dropwise addition of 1 M sodium hydroxide solution. The obtained mixture was extracted with ether, dried, and the solvent was evaporated to obtain intermediate b-2. LC-MS: Measured value: 482.93 ([M+H] + ), theoretical value: 481.90.

[0080] Intermediate b-2 was treated with Ac2O at 0 °C for 15 minutes under nitrogen protection, then the reaction mixture was poured into water and alkalinized by dropwise addition of NaOH solution. The resulting precipitate was washed with water, filtered, and dried in vacuo. The crude product was recrystallized from ethanol to obtain intermediate c-2. LC-MS: Measured value: 566.81 ([M+H] + ), theoretical value: 565.92.

[0081] In a three-necked flask, add 240 mg of copper powder, 2.7 g of K2CO3, 5 g of intermediate c-2 and 50 ml of o-dichlorobenzene, and heat the reaction at 190 °C for 2 hours under a nitrogen atmosphere; after natural cooling to room temperature, filter off the insoluble matter, concentrate the filtrate in vacuo, and purify the crude product by silica gel column chromatography (eluent: ethane:ethyl acetate = 1:1 v / v) to obtain intermediate d-2. LC-MS: measured value: 407.85 ([M+H] + ), theoretical value: 406.82.

[0082] In a three-necked flask, add 1.0 g of intermediate d-2 and an ethanol solution (38 ml) of KOH (2.6 g), and stir the reaction at room temperature for 25 minutes under a nitrogen atmosphere. Then, pour the reaction mixture into 200 ml of water, filter, wash the resulting precipitate with ethanol, and dry it with P2O5 to obtain intermediate e-2. LC-MS: measured value: 323.11 ([M+H] + ), theoretical value: 322.05.

[0083] In a three-necked flask, add 300 mg of intermediate e-2, 467 mg of iodobenzene, 300 mg of NaO t Bu, 9.4 mg of Pd(OAc)2, 20 ml of toluene and 1.1 ml of P t Bu3 in toluene solution (0.0296 mol / L), reflux for 4 hours under nitrogen protection, then add ~20 ml of toluene to the hot suspension to dissolve the product, filter, and dry and concentrate the solution in vacuo, and recrystallize to obtain intermediate f-2. LC-MS: measured value: 475.18 ([M+H] + ), theoretical value: 474.11.

[0084] (2) Synthesis of compound 47:

[0085]

[0086] Under nitrogen protection, in a three-necked flask, add 11.0 mmol of intermediate f-2, 10.0 mmol of raw material C-1, 16.0 mmol of K2CO3 and 140 ml of DMSO. After adding, stir evenly, then add 1.0 mmol of CuI and 1.0 mmol of trans-cyclohexanediamine, stir evenly, heat up to 140 °C, and react overnight (about 10 hours). Confirm the completion of the reaction by HPLC detection. Filter through diatomaceous earth, evaporate the solvent under reduced pressure, add 20 mL of ethyl acetate for extraction twice, wash with hydrochloric acid, then combine the ethyl acetate layers, spin-dry the solvent, and slurry with heptane / toluene (5 / 1) to obtain intermediate g-2. LC-MS: measured value: 718.41 ([M+H] + ), theoretical value: 717.34.

[0087] In a three-necked flask, under nitrogen protection, 2.20 mmol of boron triiodide and 1.10 mmol of intermediate g-2 were dissolved in 30 mL of 1,2,4-trichlorobenzene. After stirring at 180 °C for 20 hours, the reaction mixture was diluted with dichloromethane (50 mL), and 100 mL of sodium phosphate buffer solution with pH = 6 was added at 0 °C. The aqueous layer was separated and extracted with dichloromethane (50 mL, three times). The organic phases were combined and concentrated, and the crude product was purified by silica gel column chromatography (eluent: hexane / CH2Cl2 = 5 / 1) to obtain the target compound 47.

[0088] Synthesis of Compound 101 in Example 3:

[0089] (1) Preparation of Intermediate f-3:

[0090]

[0091] The preparation method of intermediate a-3 is the same as that of intermediate a-2, except that 2-bromobenzenethiol is used to replace 2-bromophenol to obtain intermediate a-3. LC-MS: Measured value: 574.87 ([M+H] + ), theoretical value: 573.81.

[0092] The preparation method of intermediate b-3 is the same as that of intermediate b-2, except that intermediate a-3 is used to replace intermediate a-2 to obtain intermediate b-3. LC-MS: Measured value: 514.87 ([M+H] + ), theoretical value: 513.86.

[0093] The preparation method of intermediate c-3 is the same as that of intermediate c-2, except that intermediate b-3 is used to replace intermediate b-2 to obtain intermediate c-3. LC-MS: Measured value: 598.95 ([M+H] + ), theoretical value: 597.88.

[0094] The preparation method of intermediate d-3 is the same as that of intermediate d-2, except that intermediate c-3 is used to replace intermediate c-2 to obtain intermediate d-3. LC-MS: Measured value: 439.07 ([M+H] + ), theoretical value: 438.03.

[0095] The preparation method of intermediate e-3 is the same as that of intermediate e-2, except that intermediate d-3 is used to replace intermediate d-2 to obtain intermediate e-3. LC-MS: Measured value: 355.10 ([M+H] + ), theoretical value: 354.01.

[0096] The preparation method of intermediate f-3 is the same as that of intermediate f-2, except that intermediate e-3 is used to replace intermediate e-2 to obtain intermediate f-3. LC-MS: Measured value: 507.04 ([M+H] + ), theoretical value: 506.07.

[0097] (2) Synthesis of compound 101:

[0098]

[0099] The preparation method of intermediate g-3 is the same as that of intermediate g-2, except that intermediate f-3 is used to replace intermediate f-2 to obtain intermediate g-3. LC-MS: Measured value: 750.35 ([M+H] + ), theoretical value: 749.29.

[0100] The preparation method of compound 101 is the same as that of compound 47, except that intermediate g-3 is used to replace intermediate g-2 to obtain compound 101.

[0101] Example 4 Synthesis of compound 150:

[0102] (1) Preparation of intermediate c-4:

[0103]

[0104] The preparation method of intermediate a-4 is the same as that of intermediate a-1, except that raw material B-4 is used to replace raw material B-1 to obtain intermediate a-4. LC-MS: Measured value: 730.98 ([M+H] + ), theoretical value: 729.95.

[0105] In a three-necked flask, 1.0 mmol of intermediate a-4 and 150 ml of anhydrous solvent THF were added in sequence. After complete dissolution, 5.0 mmol of CH3Li solution was slowly added dropwise under an ice bath. After the addition was completed, the ice bath was removed and stirring was continued at room temperature for 4 hours. The reaction was monitored by TLC. After the reaction was complete, the reaction was slowly quenched with water. The reaction solution was washed with water, extracted with dichloromethane, the organic phases were combined, dried over anhydrous sodium sulfate, filtered, and the solvent was evaporated to obtain intermediate b-4. LC-MS: Measured value: 763.03 ([M+H] + ), theoretical value: 762.01.

[0106] Under nitrogen protection, 1.0 mmol of intermediate b-4 was added to a three-necked flask, dissolved in 100 ml of THF solvent, gradually heated to reflux, 20.0 ml of concentrated hydrochloric acid was slowly added dropwise, and the reaction continued for 2 h under reflux. The reaction solution was cooled to room temperature, saturated NaHCO3 solution was added to neutralize the unreacted hydrochloric acid, extracted with dichloromethane, the organic phases were combined, dried over anhydrous sodium sulfate, filtered, the solvent was evaporated, purified, and intermediate c-4 was obtained. LC-MS: Measured value: 571.19 ([M+H] + )), theoretical value: 570.17.

[0107] (2) Synthesis of compound 150:

[0108]

[0109] The preparation method of intermediate d-4 is the same as that of intermediate d-1, except that raw material intermediate c-1 is replaced with intermediate c-4 to obtain intermediate d-4. LC-MS: Measured value: 770.50 ([M+H] + )), theoretical value: 769.44.

[0110] The preparation method of compound 150 is the same as that of compound 33, except that intermediate d-1 is replaced with intermediate d-4 to obtain compound 150.

[0111] Synthesis of compound 201 in Example 5:

[0112] ((1) Preparation of intermediate b-5:

[0113]

[0114] The preparation method of intermediate a-5 is the same as that of intermediate a-1, except that raw material B-1 is replaced with raw material B-5 to obtain intermediate a-5. LC-MS: Measured value: 802.82 ([M+H] + )), theoretical value: 801.75.

[0115] Under nitrogen protection, 10.0 mmol of intermediate a-5, 0.2 mmol of Pd(OAc)2, 1.38 g of K2CO3, and 150 ml of toluene were added to a three-necked flask, heated to 110 °C until the reaction solution refluxed, reacted for 12 hours, after the reaction was complete, dried over anhydrous magnesium sulfate, filtered, the solvent was rotary evaporated to obtain a crude product, and purified to obtain intermediate b-5. LC-MS: Measured value: 487.01 ([M+H] + )), theoretical value: 486.07.

[0116] ((2) Synthesis of compound 201:

[0117]

[0118] The preparation method of intermediate d-5 is the same as that of intermediate d-1, except that intermediate c-1 is replaced by intermediate b-5 to obtain intermediate d-5. LC-MS: Measured value: 686.27 ([M+H] + ) and the theoretical value is 685.35.

[0119] The preparation method of compound 201 is the same as that of compound 33, except that intermediate d-1 is replaced by intermediate d-5 to obtain compound 201.

[0120] Synthesis of compound 251 in Example 6:

[0121]

[0122] Under nitrogen protection, 10.0 mmol of intermediate f-2 and 12.0 mmol of raw material C-2 were added to a three-necked flask, dissolved in a mixed solvent (90 ml of toluene, 45 ml of ethanol), and then 1×10- 4 mol of Pd(PPh3)4 and 20 mL of a 3 mol / L aqueous solution of K2CO3 were added. The reaction was heated under reflux for 25 hours. Samples were taken for TLC to confirm the completion of the reaction. After cooling to room temperature, the reaction mixture was filtered through a diatomaceous earth pad, rinsed with chloroform, and the resulting filtrate was evaporated under vacuum. The crude product was purified by silica gel column chromatography (eluent: PE:DCM = 5:2) to obtain intermediate g-6. LC-MS: Measured value: 748.20 ([M+H] + ) and the theoretical value is 747.26.

[0123] The preparation method of compound 251 is the same as that of compound 47, except that intermediate g-2 is replaced by intermediate g-6 to obtain compound 251.

[0124] Synthesis of compound 298 in Example 7:

[0125]

[0126] The preparation method of intermediate g-7 is the same as that of intermediate g-6, except that intermediate f-2 is replaced by intermediate f-3 to obtain intermediate g-7. LC-MS: Measured value: 780.15 ([M+H] + ) and the theoretical value is 779.22.

[0127] The preparation method of compound 298 is the same as that of compound 47, except that intermediate g-2 is replaced by intermediate g-7 to obtain compound 298.

[0128] Synthesis of compound 338 in Example 8:

[0129]

[0130] The preparation method of intermediate d-8 is the same as that of intermediate g-6, except that intermediate c-4 is used to replace intermediate f-2 to obtain intermediate d-8. LC-MS: Measured value: 800.30 ([M+H] + ) and the theoretical value is 799.37.

[0131] The preparation method of compound 338 is the same as that of compound 47, except that intermediate d-8 is used to replace intermediate g-2 to obtain compound 338.

[0132] Synthesis of compound 377 in Example 9:

[0133]

[0134] The preparation method of intermediate d-9 is the same as that of intermediate g-6, except that intermediate b-5 is used to replace intermediate f-2 to obtain intermediate d-9. LC-MS: Measured value: 716.32 ([M+H] + ) and the theoretical value is 715.27.

[0135] The preparation method of compound 377 is the same as that of compound 47, except that intermediate d-9 is used to replace intermediate g-2 to obtain compound 377.

[0136] Synthesis of compound 422 in Example 10:

[0137] (1) Preparation of intermediate f-10:

[0138]

[0139] The preparation method of intermediate a-10 is the same as that of intermediate a-2, except that raw material A-10 is used to replace raw material A-2 to obtain intermediate a-10. LC-MS: Measured value: 450.88 ([M+H] + ) and the theoretical value is 449.83.

[0140] The preparation method of intermediate a-11 is the same as that of intermediate a-10, except that 2-bromobenzenethiol is used to replace 2-bromophenol to obtain intermediate a-11. LC-MS: Measured value: 558.90 ([M+H] + ) and the theoretical value is 557.83.

[0141] The preparation method of intermediate b-10 is the same as that of intermediate b-2, except that intermediate a-11 is used to replace intermediate a-2 to obtain intermediate b-10. LC-MS: Measured value: 498.92 ([M+H] + ) and the theoretical value is 497.88.

[0142] The preparation method of intermediate c-10 is the same as that of intermediate c-2, except that intermediate b-10 is used to replace intermediate b-2 to obtain intermediate c-10. LC-MS: Measured value: 582.97 ([M+H] + ) and the theoretical value is 581.90.

[0143] The preparation method of intermediate d-10 is the same as that of intermediate d-2, except that intermediate c-10 is used to replace intermediate c-2 to obtain intermediate d-10. LC-MS: Measured value: 423.07 ([M+H] + ) and the theoretical value is 422.05.

[0144] The preparation method of intermediate e-10 is the same as that of intermediate e-2, except that intermediate d-10 is used to replace intermediate d-2 to obtain intermediate e-10. LC-MS: Measured value: 339.08 ([M+H] + ) and the theoretical value is 338.03.

[0145] The preparation method of intermediate f-10 is the same as that of intermediate f-2, except that intermediate e-10 is used to replace intermediate e-2 to obtain intermediate f-10. LC-MS: Measured value: 491.02 ([M+H] + ) and the theoretical value is 490.09.

[0146] (2) Synthesis of compound 422:

[0147]

[0148] The preparation method of intermediate g-10 is the same as that of intermediate d-1, except that intermediate f-10 is used to replace intermediate c-1 to obtain intermediate g-10. LC-MS: Measured value: 734.36 ([M+H] + ) and the theoretical value is 733.31.

[0149] The preparation method of compound 422 is the same as that of compound 47, except that intermediate g-10 is used to replace intermediate g-2 to obtain compound 422.

[0150] Synthesis of compound 7 in Example 11:

[0151]

[0152] The preparation method of intermediate d-11 is the same as that of intermediate d-1, except that raw material C-3 is used to replace raw material C-1 to obtain intermediate d-11. LC-MS: Measured value: 756.35 ([M+H] + ) and the theoretical value is 755.26.

[0153] The preparation method of Compound 7 is the same as that of Compound 33, except that Intermediate d-11 is used to replace Intermediate d-1 to obtain Compound 7.

[0154] Synthesis of Compound ref-1 in Example 12:

[0155] (1) Preparation of Intermediate f-12:

[0156]

[0157] The preparation method of Intermediate f-12 is the same as that of Intermediate f-2, except that Raw Material A-12 is used to replace Raw Material A-2, and finally Intermediate f-12 is obtained. LC-MS: Measured value: 441.26 ([M+H] + )), Theoretical value: 440.15.

[0158] (2) Synthesis of Compound ref-1:

[0159]

[0160] The preparation method of Compound ref-1 is the same as that of Compound 33, except that Intermediate f-12 is used to replace Intermediate d-1 to obtain Compound ref-1.

[0161] Synthesis of Compound ref-2 in Example 13:

[0162] (1) Preparation of Intermediate f-13:

[0163]

[0164] The preparation method of Intermediate f-13 is the same as that of Intermediate f-3, except that Raw Material A-13 is used to replace Raw Material A-2, and finally Intermediate f-13 is obtained. LC-MS: Measured value: 473.05 ([M+H] + )), Theoretical value: 472.11.

[0165] (2) Synthesis of Compound ref-2:

[0166]

[0167] The preparation method of Compound ref-2 is the same as that of Compound 33, except that Intermediate f-13 is used to replace Intermediate d-1 to obtain Compound ref-2.

[0168] Synthesis of Compound ref-3 in Example 14:

[0169] (1) Preparation of Intermediate c-14:

[0170]

[0171] The preparation method of intermediate c-14 is the same as that of intermediate c-4, except that raw material A-14 is used to replace raw material A-1, and finally intermediate c-14 is obtained. LC-MS: Measured value: 493.39 ([M+H] + ) and the theoretical value is 492.26.

[0172]

[0173] The preparation method of compound ref-3 is the same as that of compound 33, except that intermediate c-14 is used to replace intermediate d-1 to obtain compound ref-3.

[0174] Synthesis of compound ref-4 in Example 15:

[0175] (1) Preparation of intermediate b-15:

[0176]

[0177] The preparation method of intermediate b-15 is the same as that of intermediate b-5, except that raw material A-15 is used to replace raw material A-1, and finally intermediate b-15 is obtained. LC-MS: Measured value: 409.12 ([M+H] + ) and the theoretical value is 408.16.

[0178]

[0179] The preparation method of compound ref-4 is the same as that of compound 33, except that intermediate b-15 is used to replace intermediate d-1 to obtain compound ref-4.

[0180] The structural characterizations of the compounds obtained in each example are shown in Table 1

[0181] Table 1

[0182]

[0183] The compounds of the present invention can be used in light-emitting devices and can be used as a dopant material for the light-emitting layer. The physical and chemical properties of the compounds prepared in the above examples of the present invention were tested, and the test results are shown in Table 2:

[0184] Table 2

[0185]

[0186]

[0187] Note: Glass transition temperature T gDetermined by differential scanning calorimetry (DSC, DSC204F1 differential scanning calorimeter from Netzsch, Germany), with a heating rate of 10 °C / min; the thermal weight loss temperature T d is the temperature at which the weight loss is 1% in a nitrogen atmosphere, measured on a TGA-50H thermogravimetric analyzer from Shimadzu, Japan, with a nitrogen flow rate of 20 mL / min; the highest occupied molecular orbital (HOMO) energy level is tested by an ionization energy test system (IPS-3), and the test is carried out in a nitrogen environment; Eg is tested by a double-beam ultraviolet-visible spectrophotometer (model: TU-1901), and LUMO = HOMO + Eg; PLQY (fluorescence quantum yield) and FWHM (full width at half maximum) are obtained by testing with a Fluorolog-3 series fluorescence spectrometer from Horiba in the thin film state. τ (transient) is obtained by testing with a Fluorolog-3 series fluorescence spectrometer from Horiba in the thin film state, and k r (radiative transition rate) = 1 / τ.

[0188] As can be seen from the data in Table 2 above, the compounds of the present invention have relatively high glass transition temperatures and decomposition temperatures. When used as a doping material for the light-emitting layer, it can inhibit the crystallization and phase separation of the material; at the same time, it can also inhibit the decomposition of the material at high brightness, improving the working life of the device. In addition, the compounds of the present application have appropriate HOMO energy levels. When doped into the host material as a doping material, it is beneficial to inhibit the generation of carrier traps, improve the main guest energy transfer efficiency, and thus improve the light-emitting efficiency of the device.

[0189] The compounds of the present invention have relatively high fluorescence quantum efficiencies as doping materials, and the fluorescence quantum efficiency of the materials is close to 100%; at the same time, the spectral FWHM of the materials is relatively narrow, which can effectively improve the color gamut of the device and improve the light-emitting efficiency of the device; finally, the evaporation decomposition temperature of the materials is relatively high, which can inhibit the evaporation decomposition of the materials, and the radiative transition rate of the materials is relatively high, which can effectively improve the device life.

[0190] The application effects of the OLED materials synthesized by the present invention in the device are described in detail below through Device Examples 1-11 and Device Comparative Examples 1-6. The manufacturing processes of Device Examples 2-11 and Device Comparative Examples 1-6 of the present invention are exactly the same as those of Device Example 1, and the same substrate materials and electrode materials are used, and the film thicknesses of the electrode materials are also kept consistent. The difference is that the light-emitting layer materials in the devices are replaced. The layer structures and test results of each device example are shown in Tables 3 and 4 respectively.

[0191] Device Example 1

[0192] As Figure 1As shown, the transparent substrate layer 1 is a transparent PI film. The ITO anode layer 2 (with a film thickness of 150 nm) is washed, that is, washed successively with a cleaning agent (Semiclean M-L20), pure water, and then dried, and then washed with ultraviolet-ozone to remove organic residues on the surface of the transparent ITO. On the ITO anode layer 2 after the above washing, using a vacuum evaporation device, HT-1 and HI-1 with a film thickness of 10 nm are evaporated as the hole injection layer 3, and the mass ratio of HT-1 and HI-1 is 97:3. Then, HT-1 with a thickness of 60 nm is evaporated as the hole transport layer 4. Subsequently, EB-1 with a thickness of 30 nm is evaporated as the electron blocking layer 5. After the evaporation of the above electron blocking material is completed, the light-emitting layer 6 of the OLED light-emitting device is fabricated. CBP is used as the host material, and compound 33 is used as the doping material. The mass ratio of CBP and compound 33 is 97:3, and the film thickness of the light-emitting layer is 30 nm. After the above light-emitting layer 6, HB-1 is continuously vacuum-evaporated with a film thickness of 5 nm, and this layer is the hole blocking layer 7. After the above hole blocking layer 7, ET-1 and Liq are continuously vacuum-evaporated, and the mass ratio of ET-1 and Liq is 1:1, with a film thickness of 30 nm. This layer is the electron transport layer 8. On the electron transport layer 8, a LiF layer with a film thickness of 1 nm is fabricated through a vacuum evaporation device, and this layer is the electron injection layer 9. On the electron injection layer 9, a Mg:Ag electrode layer with a film thickness of 80 nm is fabricated through a vacuum evaporation device, and the mass ratio of Mg and Ag is 1:9. This layer is used as the cathode layer 10.

[0193] The application effects of the synthesized OLED materials of the present invention in devices are described in detail below through device examples 12-22 and device comparative examples 7-12. The manufacturing processes of devices in device examples 13-22 and device comparative examples 7-12 of the present invention are exactly the same as those of device example 12, and the same substrate materials and electrode materials are used, and the film thicknesses of the electrode materials are also kept consistent. The difference is that the light-emitting layer materials in the devices are replaced. The layer structures and test results of each device example are shown in Tables 3 and 4 respectively.

[0194] Device Example 12

[0195] The transparent substrate layer 1 is a transparent PI film. The ITO anode layer 2 (with a film thickness of 150 nm) is washed, that is, washed successively with a cleaning agent (Semiclean M-L20), pure water, and then dried, and then washed with ultraviolet-ozone to remove organic residues on the surface of the transparent ITO. On the ITO anode layer 2 after the above-mentioned washing, using a vacuum evaporation device, HT-1 and HI-1 with a film thickness of 10 nm are evaporated as the hole injection layer 3, and the mass ratio of HT-1 and HI-1 is 97:3. Then, HT-1 with a thickness of 60 nm is evaporated as the hole transport layer 4. Subsequently, EB-1 with a thickness of 30 nm is evaporated as the electron blocking layer 5. After the evaporation of the above-mentioned electron blocking material is completed, the light-emitting layer 6 of the OLED light-emitting device is fabricated, using CBP and DMAC-BP as the double host materials and compound 33 as the doping material, and the mass ratio of CBP, DMAC-BP, and compound 33 is 67:30:3, and the film thickness of the light-emitting layer is 30 nm. After the above light-emitting layer 6, HB-1 is continuously vacuum-evaporated with a film thickness of 5 nm, and this layer is the hole blocking layer 7. After the above hole blocking layer 7, ET-1 and Liq are continuously vacuum-evaporated, and the mass ratio of ET-1 and Liq is 1:1, and the film thickness is 30 nm, and this layer is the electron transport layer 8. On the electron transport layer 8, a LiF layer with a film thickness of 1 nm is fabricated through a vacuum evaporation device, and this layer is the electron injection layer 9. On the electron injection layer 9, a Mg:Ag electrode layer with a film thickness of 80 nm is fabricated through a vacuum evaporation device, and the mass ratio of Mg and Ag is 1:9, and this layer is used as the cathode layer 10.

[0196] The molecular structural formulas of the related materials are as follows:

[0197]

[0198] After the OLED light-emitting device is completed as described above, the anode and the cathode are connected by a well-known drive circuit, and the current efficiency, external quantum efficiency, and the lifetime of the device are measured. The device examples and comparative examples prepared by the same method are shown in Table 3; the test results of the current efficiency, external quantum efficiency, and lifetime of the obtained devices are shown in Table 4.

[0199] Table 3

[0200]

[0201]

[0202]

[0203] Table 4

[0204]

[0205]

[0206] Note: The voltage, current efficiency, and emission peak are measured using an IVL (current-voltage-luminance) test system (Suzhou FushiDa Scientific Instrument Co., Ltd.); the lifetime test system is the EAS-62C type OLED device lifetime tester from System Technology Research Co., Ltd. of Japan; LT95 refers to the time when the device luminance decays to 95%; all data are measured at 10 mA / cm 2 under the test.

[0207] From the device data results in Table 4, it can be seen that compared with device Comparative Examples 1-12, for the compounds of the present invention in single-host system devices (Examples 1-11), the current efficiency of the devices is relatively high compared with the comparative examples; in double-host system devices (Examples 12-22), the device efficiency shows good results; compared with device Comparative Examples 1-12, for the compounds of the present invention in single-host system devices (Examples 1-11) and double-host system devices (Examples 12-22), the device lifetimes are all greatly improved compared with the OLED devices of known materials.

[0208] In summary, the above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. An organic compound based on boron-nitrogen fused rings, characterized in that, The structure of the boron-nitrogen fused ring-based organic compound is shown in general formula (1): In general formula (1), Z1 and Z2 each independently represent C-R1; Two adjacent Z2s can also be connected into a ring through a C-C bond; X1 and X2 each independently represent a single bond, O, S, or C(R1)2; L represents one of C6 arylene groups, and n represents 0 or 1; R2 represents the structure shown in general formula (2) or general formula (3): In general formula (2) and general formula (3), Z3-Z5 each appear the same or differently and represent C-R1 or N; In general formula (2), two Z4s can also be connected into a ring through a C-C bond; In general formula (3), at least one Z5 represents N; R1 each appears the same or differently and represents one of H, deuterium atom, halogen atom, cyano group, adamantyl group, methyl group, trifluoromethyl group, ethyl group, isopropyl group, isobutyl group, tert-butyl group, cyclopentyl group, methyl-substituted cyclopentyl group, cyclohexyl group, phenyl group, deuterated phenyl group, biphenyl group, deuterated biphenyl group, terphenyl group, naphthyl group, pyridyl group, phenyl-substituted pyridyl group, benzofuranyl group, dibenzofuranyl group, dibenzothiophenyl group, carbazolyl group, N-phenylcarbazolyl group, 9,9-dimethylfluorenyl group, phenyl-substituted amino group, tert-butylbenzene-substituted amino group, tert-butyl-substituted dibenzofuranyl group, methyl-substituted phenyl group, ethyl-substituted phenyl group, isopropyl-substituted phenyl group, tert-butyl-substituted phenyl group, methyl-substituted biphenyl group, ethyl-substituted biphenyl group, isopropyl-substituted biphenyl group, tert-butyl-substituted biphenyl group, phenyl-substituted tert-butyl group, phenyl-substituted triazinyl group.

2. The organic compound based on boron-nitrogen fused rings according to claim 1, wherein The general formula (2) is represented by the following structure: The general formula (3) is represented by the following structure: R1 each appears the same or differently and represents one of H, deuterium atom, halogen atom, cyano group, adamantyl group, methyl group, trifluoromethyl group, ethyl group, isopropyl group, isobutyl group, tert-butyl group, cyclopentyl group, methyl-substituted cyclopentyl group, cyclohexyl group, phenyl group, deuterated phenyl group, biphenyl group, deuterated biphenyl group, terphenyl group, naphthyl group, pyridyl group, phenyl-substituted pyridyl group, benzofuranyl group, dibenzofuranyl group, dibenzothiophenyl group, carbazolyl group, N-phenylcarbazolyl group, 9,9-dimethylfluorenyl group, phenyl-substituted amino group, tert-butylbenzene-substituted amino group, tert-butyl-substituted dibenzofuranyl group, methyl-substituted phenyl group, ethyl-substituted phenyl group, isopropyl-substituted phenyl group, tert-butyl-substituted phenyl group, methyl-substituted biphenyl group, ethyl-substituted biphenyl group, isopropyl-substituted biphenyl group, tert-butyl-substituted biphenyl group, phenyl-substituted tert-butyl group, phenyl-substituted triazinyl group.

3. The organic compound based on a boron-nitrogen fused ring according to claim 1, wherein The structure of the organic compound is shown in any one of general formulas (4) to (9): In general formulas (4) to (9), the meanings of Z1-Z5, X1, and X2 are the same as those defined in claim 1.

4. The organic compound based on a boron-nitrogen fused ring according to claim 1, characterized in that, R1 is one of H, deuterium atom, cyano group, fluorine atom, adamantyl group, methyl group, trifluoromethyl group, ethyl group, isopropyl group, isobutyl group, tert-butyl group, cyclopentyl group, methyl-substituted cyclopentyl group, cyclohexyl group, phenyl group, deuterated phenyl group, biphenyl group, deuterated biphenyl group, terphenyl group, naphthyl group, anthracenyl group, phenanthryl group, pyridyl group, phenyl-substituted pyridyl group, benzofuranyl group, dibenzofuranyl group, dibenzothiophenyl group, carbazolyl group, N-phenylcarbazolyl group, 9,9-dimethylfluorenyl group, phenyl-substituted amino group, tert-butylbenzene-substituted amino group, tert-butyl-substituted dibenzofuranyl group, methyl-substituted phenyl group, ethyl-substituted phenyl group, isopropyl-substituted phenyl group, tert-butyl-substituted phenyl group, methyl-substituted biphenyl group, ethyl-substituted biphenyl group, isopropyl-substituted biphenyl group, tert-butyl-substituted biphenyl group, phenyl-substituted tert-butyl group, phenyl-substituted triazinyl group.

5. The organic compound based on boron-nitrogen fused rings according to claim 1, wherein The number of Z3 represented as N is 1, 2 or 3; X1 and X2 are the same.

6. The organic compound based on a boron-nitrogen fused ring according to claim 3, characterized in that, The structure of the organic compound is any one of general formulas (5) to (8).

7. An organic compound based on boron-nitrogen fused rings, characterized in that, The specific structural formula of the organic compound is any one of the following structures:

8. An organic electroluminescent device, comprising a cathode and an anode, and an organic light-emitting functional layer therebetween, the organic light-emitting functional layer including a light-emitting layer, characterized in that, The light-emitting layer contains the boron-nitrogen fused-ring-based organic compound according to any one of claims 1-7.

9. The organic electroluminescent device according to claim 8, wherein The light-emitting layer comprises a host material and a doping material, characterized in that the doping material contains the boron-nitrogen fused-ring-based organic compound according to any one of claims 1-7.

10. The organic electroluminescent device according to claim 8, wherein the light-emitting layer comprises a first host material, a second host material, and a doping material, characterized in that, At least one of the first host material and the second host material is a TADF material, and the doping material is the boron-nitrogen fused-ring-based organic compound according to any one of claims 1-7.

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