Phosphorescent complex, preparation method thereof and organic electroluminescent device

Abstract

The invention provides a phosphorescent complex, a preparation method thereof and an organic electroluminescent device, the phosphorescent complex has a structure as shown in a formula LA, and the phosphorescent complex enables the organic electroluminescent device to have high current efficiency, low driving voltage, long phosphorescent lifetime and excellent color development effect.

Description

Technical Field

[0001] The invention belongs to the technical field of organic metal photoelectric materials and relates to a phosphorescent complex and a preparation method thereof and an organic electroluminescent device. Background Art

[0002] Display devices are important in many fields, and there is a continuous demand for improved performance. Currently, the efficiency and life of green and yellow organic phosphorescent materials basically meet the needs of industrial production, but high-performance red phosphorescent materials are still to be developed.

[0003] In the organic electroluminescent device, when charges are injected into a light-emitting layer formed between a positive electrode and a negative electrode, electrons and holes are recombined with each other in the light-emitting layer to form excitons, and thus energy of the excitons is converted into light.

[0004] Examples of organic optoelectronic devices include organic light emitting diodes / devices (OLEDs), organic phototransistors, organic photovoltaic cells, and organic photodetectors. For OLEDs, organic materials can have performance advantages over conventional materials. OLEDs are becoming an increasingly popular technology for applications such as flat panel displays, lighting, and backlighting.

[0005] At present, the main factor restricting the rapid development of organic electroluminescent materials is the lack of high-efficiency red light phosphorescent materials. Compared with the most widely used red light phosphorescent materials based on platinum complexes, regular octahedral cyclometallated iridium complexes have the characteristics of high efficiency, long life, simple synthesis, and easy dimming. They have become a very important research direction for the design of new high-efficiency red light phosphorescent materials. Summary of the invention

[0006] In view of the deficiencies of the prior art, the object of the present invention is to provide a phosphorescent complex and a preparation method thereof and an organic electroluminescent device. The phosphorescent complex of the present invention has more substituted benzene rings than other materials, so that it has stronger conductivity, requires less driving voltage when used, and is more energy-efficient. In addition, because the substitution of the benzene ring makes its luminous performance more superior and its service life longer, the substitution of the tert-butyl group makes the compound have better chirality and optical rotation, and the full width at half maximum is effectively reduced through experiments. In addition, the color gamut presented by the organic electroluminescent device is wider and closer to the natural color.

[0007] To achieve this object, the present invention adopts the following technical solutions:

[0008] In one aspect, the present invention provides a phosphorescent complex having a structure as shown in the following formula LA:

[0009]

[0010] Wherein ring Ra and ring Rb independently represent absence or are selected from unsubstituted C4-C12 aryl groups, preferably absence, benzene ring or naphthalene ring;

[0011] R1 to R3 each independently represent hydrogen, deuterium, halogen, substituted or unsubstituted C1-C10 alkyl, substituted or unsubstituted C6-C24 cycloalkyl, substituted or unsubstituted C3-C30 heteroalkyl, substituted or unsubstituted C6-C24 aralkyl, substituted or unsubstituted C1-C15 alkoxy, substituted or unsubstituted C6-C24 aryloxy, substituted or unsubstituted C1-C3 silyl, substituted or unsubstituted C1-C3 germyl, ester, nitrile, isonitrile, thiol, sulfinyl, sulfonyl, phosphino, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C6-C30 heteroaryl;

[0012] R4 to R7 represent substitutions at any position on the ring where they are located, and the substituents are selected from hydrogen, deuterium, halogen, substituted or unsubstituted C1-C10 alkyl, substituted or unsubstituted C6-C24 cycloalkyl, substituted or unsubstituted C3-C30 heteroalkyl, substituted or unsubstituted C6-C24 aralkyl, substituted or unsubstituted C1-C15 alkoxy, substituted or unsubstituted C6-C24 aryloxy, substituted or unsubstituted C1-C3 silyl, substituted or unsubstituted C1-C3 germyl, ester, nitrile, isonitrile, thio, sulfinyl, sulfonyl, phosphino, substituted or unsubstituted C6-C12 aryl, substituted or unsubstituted C6-C12 heteroaryl;

[0013] The substituents in the above-mentioned substituted groups can be selected from one or a combination of at least two of the following groups: deuterium, fluorine, methyl, ethyl, propyl, isopropyl, butyl, tert-butyl, isobutyl, pentyl, isopentyl, neopentyl, hexyl, 2-methylpentyl, 3-methylpentyl, 2,3-dimethylbutyl, 2,2-dimethylbutyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, methoxy, ethoxy, propoxy, phenoxy, C1-C3 silanyl, C1-C3 germanyl, ester group, nitrile group, isonitrile group, sulfide group, sulfinyl group, sulfonyl group, and phosphine group.

[0014] Preferably, R1 to R7 are each independently selected from methyl, ethyl, propyl, isopropyl, halogen, deuterium, butyl, tert-butyl, isobutyl, At least one of a trimethylsilyl group, a cyclohexyl group, a cyano group, or a substituted or unsubstituted benzene ring.

[0015] Preferably, the phosphorescent complex is any one of the following complexes:

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[0045]

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[0049]

[0050]

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[0077]

[0078] Some specific structures are listed above, including but not limited to the above structures. Other specific structures can be obtained by simple transformation of the substitution positions between the groups, which will not be described one by one here.

[0079] The present invention also provides a method for synthesizing the above phosphorescent complex, which specifically comprises the following steps:

[0080] S1, dissolving the compound represented by formula A and iridium trichloride in ethylene glycol ether and water, and performing reflux reaction under the protection of inert gas, the reaction time is 12-28h, and after the reaction is completed, cooling, precipitating, filtering, washing and drying are performed to obtain the bridging ligand compound represented by formula B;

[0081] S2, the bridging ligand compound represented by formula B, the diketone derivative represented by formula C, anhydrous potassium carbonate and ethylene glycol ethyl ether are added to a three-necked flask in sequence, and reflux reaction is carried out under the protection of inert gas, and the reaction time is 12-28 hours. After the reaction is completed, cooling, precipitation, suction filtration, washing, drying, column chromatography, and concentration are performed to obtain the phosphorescent complex represented by formula LA;

[0082] The synthetic route of the phosphorescent complex is as follows:

[0083]

[0084] Preferably, in step S1, the reaction molar ratio of the compound represented by formula A to iridium trichloride is 2.0-3.0:1.0, for example, 2.0:1.0, 2.3:1.0, 2.5:1.0, 2.8:1.0 or 3.0:1.0.

[0085] Preferably, in step S2, the reaction molar ratio of the bridging ligand compound represented by formula B to the diketone derivative represented by formula C is 1.0:2.0-4.0, for example, 1.0:2.0, 1.0:2.2, 1.0:2.5, 1.0:2.8, 1.0:3.0, 1.0:3.3, 1.0:3.5, 1.0:3.8 or 1.0:4.0.

[0086] Preferably, in step S1, the reaction temperature is 105-120°C, for example, 105°C, 108°C, 110°C, 115°C, 118°C or 120°C.

[0087] Preferably, in step S2, the reaction temperature is 105-120°C, for example, 105°C, 108°C, 110°C, 115°C, 118°C or 120°C.

[0088] Preferably, in step S1, the post-treatment process is: cooling to room temperature, precipitating a precipitate, filtering under reduced pressure, rinsing with anhydrous ethanol and petroleum ether in sequence, and drying to obtain a bridging ligand compound represented by formula B.

[0089] Preferably, in step S2, the post-treatment process is: cooling to room temperature, filtering under reduced pressure, rinsing the filter cake with ethanol, drying at -0.1 MPa, 50°C, passing through a silica gel column, and spinning the obtained filtrate to obtain the phosphorescent complex represented by formula LA.

[0090] Preferably, the diketone derivative represented by formula C is selected from the following compounds:

[0091]

[0092] The present invention further provides the use of the above-mentioned phosphorescent complex in an organic electroluminescent device.

[0093] The invention also provides an organic electroluminescent device comprising the phosphorescent complex.

[0094] Preferably, the organic electroluminescent device comprises: a first electrode, a second electrode and at least one organic layer, wherein the organic layer is located between the first electrode and the second electrode, and at least one of the organic layers contains the phosphorescent complex as described above; the phosphorescent complex exists in the organic layer in a single form or mixed with other substances.

[0095] Preferably, the organic layer includes at least a hole injection layer, a hole transport layer, a layer having both hole injection and hole transport skills, an electron blocking layer, a light-emitting layer, a hole blocking layer, an electron transport layer, an electron injection layer and a layer having both electron transport and electron injection skills, or a combination of at least two of them.

[0096] Preferably, the light-emitting layer includes a host material and a doping material, the host material includes a fluorescent host and a phosphorescent host, and the doping material is the above-mentioned phosphorescent complex.

[0097] Preferably, the organic electroluminescent device comprises a light-emitting layer, and the light-emitting layer contains the above-mentioned phosphorescent complex.

[0098] Preferably, the mixing ratio of the host material to the doping material is (85:15) to (99:1), for example, 85:15, 86:14, 87:13, 88:12, 89:11 or 90:10.

[0099] The organic light-emitting device provided by the present invention can be used in any of the following electronic devices for display or light emission: computers, tablet computers, televisions, phones, virtual reality or augmented reality displays, etc.

[0100] Compared with the prior art, the present invention has the following beneficial effects:

[0101] The phosphorescent complex of the present invention can make the organic electroluminescent device have higher current efficiency, lower driving voltage, longer phosphorescent life and excellent color rendering effect; the preparation process of the phosphorescent complex provided by the present invention is simple and efficient, and the obtained product has high purity. DETAILED DESCRIPTION

[0102] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0103] Example 1

[0104] The synthesis of compound LA-001, the specific steps are as follows:

[0105]

[0106] S1. Weigh A-001 (1.0 eq) and A-002 (3.0 eq), add xylene and sodium acetate (1.0 eq), replace twice with N2, add palladium acetate (0.05 eq) under N2 protection, replace twice with N2 again, heat to 110°C under N2 protection for 12 hours, cool the reaction to room temperature, wash with water, dry the organic phase with anhydrous sodium sulfate, evaporate xylene to obtain a crude product, and recrystallize the crude product with ethyl acetate to obtain B-001 (yield 96.8%).

[0107] S2. Weigh B-001 (2.3 eq), IrCl3·3H2O (1.0 eq), ethylene glycol ether and water respectively and add them into the reaction system. Heat and reflux for 24 h under N2 protection, then cool to room temperature. A precipitate is precipitated. It is filtered under reduced pressure, washed with anhydrous ethanol and petroleum ether in turn, and dried to obtain C-001 (yield 72.8%).

[0108] S3. Weigh C-001 (1.0 eq), K2CO3 (10.0 eq), and ethylene glycol ether and add them to the reaction system respectively. Under the protection of N2, add D-001 (3,7-diethyl-4,6-nonanedione) (3.0 eq), raise the temperature to 120°C, heat under reflux for 24 h, cool to room temperature, filter under reduced pressure, rinse the filter cake with ethanol, dry at -0.1 MPa, 50°C, pass through a silica gel column, and spin-dry the filtrate to obtain LA-001 (yield: 45.8%).

[0109] HPLC purity: >99%.

[0110] Mass spectrometry test value: 1204.57.

[0111] Elemental Analysis:

[0112] Theoretical value: C, 70.73%; H, 5.56%; N, 2.32%; O, 5.31%;

[0113] Test values: C, 70.74%; H, 5.58%; N, 2.33%; O, 5.32%.

[0114] H NMR spectrum: 1 H-NMR (400 MHz, deuterated chloroform) δ8.53 (d, 2H), 8.37-8.32 (m, 2H), 8.32-8.26 (m, 2H), 7.93-7.86 (m, 7H), 7.84 (s, 1H), 7.71 (dd, 2H), 7.50-7.39 (m, 4H), 7.36-7.29 (m, 6H), 5.94 (d, 1H), 2.70 (p, 1H), 2.48 (pd, 1H), 1.67-1.48 (m, 8H), 1.35 (s, 18H), 0.89 (q, 12H).

[0115] Example 2

[0116] The synthesis of compound LA-019, the specific steps are as follows:

[0117]

[0118] S1. Weigh A-019 (1.0 eq) and A-002 (3.0 eq), add xylene and sodium acetate (1.0 eq), replace twice with N2, add palladium acetate (0.05 eq) under N2 protection, replace twice with N2 again, heat to 110°C under N2 protection for 12 hours, cool the reaction to room temperature, wash with water, dry the organic phase with anhydrous sodium sulfate, evaporate xylene to obtain a crude product, and recrystallize the crude product with ethyl acetate to obtain B-019 (yield 92.1%).

[0119] S2. Weigh B-019 (1.0eq) and B-020 (1.1eq), add xylene and potassium carbonate (3.0eq), replace twice with N2, add palladium acetate (0.05eq) under N2 protection, replace twice with N2 again, heat to 90°C under N2 protection for 12h, cool the reaction to room temperature, wash with water, dry the organic phase with anhydrous sodium sulfate, evaporate xylene to obtain a crude product, and recrystallize the crude product with ethyl acetate to obtain C-019 (yield 90.5%).

[0120] S3. Weigh C-019 (2.3 eq), IrCl3·3H2O (1.0 eq), ethylene glycol ether and water respectively and add them into the reaction system. Heat and reflux for 24 h under N2 protection, then cool to room temperature. A precipitate is precipitated. Reduce the pressure and filter it. Wash it with anhydrous ethanol and petroleum ether in turn, and dry it to obtain D-019 (yield 74.6%).

[0121] S4. Weigh D-019 (1.0 eq), K2CO3 (10.0 eq), and ethylene glycol ether and add them to the reaction system respectively. Under N2 protection, add D-001 (3,7-diethyl-4,6-nonanedione) (3.0 eq), raise the temperature to 120°C, heat under reflux for 12 hours, cool to room temperature, filter under reduced pressure, rinse the filter cake with ethanol, dry at -0.1 MPa, 50°C, pass through a silica gel column, and spin-dry the filtrate to obtain LA-019 (yield: 44.6%).

[0122] HPLC purity: >99%.

[0123] Mass spectrometry test value: 1256.73.

[0124] Elemental Analysis:

[0125] Theoretical value: C, 71.62%; H, 5.65%; N, 2.22%; O, 5.09%;

[0126] Test values: C, 71.63%; H, 5.66%; N, 2.23%; O, 5.10%.

[0127] H NMR spectrum:

[0128] 1 H-NMR (400 MHz, deuterated chloroform) δ8.54 (d, 2H), 8.35 (dd, 2H), 7.95-7.88 (m, 4H), 7.72-7.63 (m, 4H), 7.59-7.52 (m, 4H), 7.50-7.29 (m, 14H), 5.81 (d, 1H), 2.76 (p, 1H), 2.61 (pd, 1H), 1.67-1.47 (m, 8H), 1.35 (s, 18H), 0.89 (t, 12H).

[0129] Example 3

[0130] The synthesis of compound LA-002 is as follows:

[0131]

[0132] S1. Weigh A-002 (1.0 eq) and add it to DCM. Add Br2 (5.0 eq) dropwise at a rate of 0.5 drops per second at -78°C. After the addition is completed, warm the temperature to room temperature and react for 15 minutes. After the reaction is completed, slowly pour the system into an iced 70% sodium bisulfite solution to quench, add DCM for extraction, wash the organic phase with water, dry the organic phase with anhydrous sodium sulfate, and then evaporate the solvent at -0.1 mPa, 50°C to obtain a crude product. Dissolve the crude product with a small amount of DCM and evaporate it repeatedly. Then recrystallize it with EA to obtain B-002 (yield 42.3%).

[0133] S2. Weigh B-002 (1.0eq), B-003 (1.05eq), and potassium carbonate (3.0eq), add to dioxane, replace with N2 twice, add tetrakistriphenylphosphine palladium under N2 protection, replace with N2 again, react for 16 hours under N2 protection, and after the reaction is completed, filter the system hot, pour the filtrate slowly into water, filter, collect the filter cake, and dry it in vacuo at 80°C to obtain the crude product, which is purified by column chromatography to obtain C-002 (yield 33.7%).

[0134] S3. Weigh C-002 (1.0 eq) and A-002 (3.0 eq), add xylene and sodium acetate (1.0 eq), replace twice with N2, add palladium acetate (0.05 eq) under N2 protection, replace twice with N2 again, heat to 110°C under N2 protection for 12 hours, cool the reaction to room temperature, wash with water, dry the organic phase with anhydrous sodium sulfate, evaporate xylene to obtain a crude product, and recrystallize the crude product with ethyl acetate to obtain D-002 (yield 93.7%).

[0135] S4. Weigh D-002 (2.3 eq), IrCl3·3H2O (1.0 eq), ethylene glycol ether and water respectively and add them into the reaction system. Heat and reflux for 24 h under N2 protection, then cool to room temperature. A precipitate is precipitated. Reduce the pressure and filter it. Wash it with anhydrous ethanol and petroleum ether in turn, and dry it to obtain E-002 (yield 77.8%).

[0136] S5. Weigh E-002 (1.0 eq), K2CO3 (10.0 eq), and ethylene glycol ether and add them to the reaction system respectively. Add D-001 (3,7-diethyl-4,6-nonanedione) (3.0 eq) under N2 protection, raise the temperature to 120°C, heat under reflux for 24 h, cool to room temperature, filter under reduced pressure, rinse the filter cake with ethanol, dry at -0.1 MPa, 50°C, pass through a silica gel column, and spin-dry the filtrate to obtain LA-002 (yield: 43.1%).

[0137] HPLC purity: >99%.

[0138] Mass spectrometry test value: 1304.58.

[0139] Elemental Analysis:

[0140] Theoretical values: C, 72.66%; H, 5.44%; N, 2.14%; O, 4.90%;

[0141] Test values: C, 72.67%; H, 5.45%; N, 2.15%; O, 4.91%.

[0142] H NMR spectrum:

[0143] 1 H NMR (400 MHz, deuterated chloroform) δ 8.54 (d, 2H), 8.35 (dd, 2H), 8.00-7.93 (m, 3H), 7.93-7.86 (m, 7H), 7.83-7.74 (m, 4H), 7.70 (dd, 2H), 7.49-7.38 (m, 4H), 7.38-7.29 (m, 6H), 5.81 (d, 1H), 2.82-2.55 (m, 2H), 1.67-1.47 (m, 8H), 1.35 (s, 18H), 0.89 (t, 12H).

[0144] Example 4

[0145] The synthesis of compound LA-074, the specific steps are as follows:

[0146]

[0147] S1. Weigh A-074 (1.0 eq) and A-075 (3.0 eq), add xylene and sodium acetate (1.0 eq), replace twice with N2, add palladium acetate (0.05 eq) under N2 protection, replace twice with N2 again, heat to 110°C under N2 protection for 12 hours, cool the reaction to room temperature, wash with water, dry the organic phase with anhydrous sodium sulfate, evaporate xylene to obtain a crude product, and recrystallize the crude product with ethyl acetate to obtain B-074 (yield 93.5%).

[0148] S2. Weigh B-074 (1.0 eq) and B-020 (1.1 eq), add xylene and potassium carbonate (3.0 eq), replace twice with N2, add palladium acetate (0.05 eq) under N2 protection, replace twice with N2 again, heat to 90 ° C under N2 protection for 12 hours, cool the reaction to room temperature, wash with water, dry the organic phase with anhydrous sodium sulfate, evaporate xylene to obtain a crude product, and recrystallize the crude product with ethyl acetate to obtain C-074 (yield 88.7%).

[0149] S3. Weigh C-074 (2.3 eq), IrCl3·3H2O (1.0 eq), ethylene glycol ether and water respectively and add them into the reaction system. Heat and reflux for 24 h under N2 protection, then cool to room temperature. A precipitate is precipitated. Reduce the pressure and filter it. Wash it with anhydrous ethanol and petroleum ether in turn, and dry it to obtain D-074 (yield 75.6%).

[0150] S4. Weigh D-074 (1.0 eq), K2CO3 (10 eq), and ethylene glycol ether and add them to the reaction system respectively. Under N2 protection, add D-001 (3,7-diethyl-4,6-nonanedione) (3.0 eq), raise the temperature to 120°C, heat under reflux for 12 h, cool to room temperature, filter under reduced pressure, rinse the filter cake with ethanol, dry at -0.1 MPa, 50°C, pass through a silica gel column, and spin-dry the filtrate to obtain LA-074 (yield 45.2%).

[0151] HPLC purity: >99%.

[0152] Mass spectrum: Test value 1344.56.

[0153] Elemental Analysis:

[0154] Theoretical value: C, 74.07%; H, 4.68%; N, 2.08%; O, 4.76%;

[0155] Test values: C, 74.08%; H, 4.70%; N, 2.09%; O, 4.76%.

[0156] H NMR spectrum:

[0157] 1 H-NMR (400 MHz, deuterated chloroform) δ8.50 (d, 2H), 8.32–8.26 (m, 2H), 8.11 (t, 2H), 7.95-7.91 (m, 4H), 7.91-7.83 (m, 8H), 7.81-7.72 (m, 8H), 7.55-7.50 (m, 3H), 7.50-7.43 (m, 3H), 7.43-7.35 (m, 4H), 7.35-7.29 (m, 4H), 5.93 (d, 1H), 2.70 (p, 1H), 2.48 (pd, 1H), 1.67-1.48 (m, 8H), 0.92-0.85 (m, 12H).

[0158] Example 5

[0159] The synthesis of compound LA-028, the specific steps are as follows:

[0160]

[0161] S1. Weigh A-028 (1.0 eq) and A-029 (3.0 eq), add xylene and sodium acetate (1.0 eq), replace twice with N2, add palladium acetate (0.05 eq) under N2 protection, replace twice with N2 again, heat to 110 ° C under N2 protection for 12 hours, cool the reaction to room temperature, wash with water, dry the organic phase with anhydrous sodium sulfate, evaporate xylene to obtain a crude product, and recrystallize the crude product with ethyl acetate to obtain B-028 (yield 96.8%).

[0162] S2. Weigh B-028 (2.3 eq), IrCl3·3H2O (1.0 eq), ethylene glycol ether and water respectively and add them into the reaction system. Heat and reflux for 24 h under N2 protection, then cool to room temperature. A precipitate is precipitated. Reduce the pressure and filter it. Wash it with anhydrous ethanol and petroleum ether in turn, and dry it to obtain C-028 (yield 70.4%).

[0163] S3. Weigh C-028 (1.0 eq), K2CO3 (10.0 eq), and ethylene glycol ether and add them to the reaction system respectively. Add D-028 (3.0 eq) under N2 protection, raise the temperature to 120°C, heat under reflux for 24 h, cool to room temperature, filter under reduced pressure, rinse the filter cake with ethanol, dry at -0.1 MPa, 50°C, pass through a silica gel column, and spin-dry the filtrate to obtain LA-028 (yield 45.3%).

[0164] HPLC purity: >99%.

[0165] Mass spectrum: Test value 1092.45.

[0166] Elemental Analysis:

[0167] Theoretical value: C, 69.21%; H, 4.67%; N, 2.56%; O, 5.86%;

[0168] Test values: C, 69.22%; H, 4.68%; N, 2.58%; O, 5.87%.

[0169] H NMR spectrum:

[0170] 1 H NMR (400 MHz, deuterated chloroform) δ 8.54 (d, 2H), 8.35 (dd, 2H), 8.32-8.26 (m, 2H), 7.93-7.82 (m, 8H), 7.78 (dd, 2H), 7.50-7.39 (m, 4H), 7.39-7.29 (m, 6H), 5.80 (hept, 1H), 2.56 (d, 3H), 2.20 (d, 3H), 1.35 (s, 18H).

[0171] Example 6

[0172] The synthesis of compound LA-092 is as follows:

[0173]

[0174] S1. Weigh A-092 (1.0 eq) and A-093 (3.0 eq), add xylene and sodium acetate (1.0 eq), replace twice with N2, add palladium acetate (0.05 eq) under N2 protection, replace twice with N2 again, heat to 110°C under N2 protection for 12 hours, cool the reaction to room temperature, wash with water, dry the organic phase with anhydrous sodium sulfate, evaporate xylene to obtain a crude product, and recrystallize the crude product with ethyl acetate to obtain B-092 (yield 71.2%).

[0175] S2. Weigh B-092 (2.3 eq), IrCl3·3H2O (1.0 eq), ethylene glycol ether and water respectively and add them into the reaction system. Heat and reflux for 24 h under N2 protection, then cool to room temperature. A precipitate is precipitated. Reduce the pressure and filter it. Wash it with anhydrous ethanol and petroleum ether in turn, and dry it to obtain C-092 (yield 75.6%).

[0176] S3. Weigh C-092 (1.0 eq), K2CO3 (10.0 eq), and ethylene glycol ether and add them to the reaction system respectively. Add D-092 (3.0 eq) under N2 protection, raise the temperature to 120°C, heat under reflux for 24 h, cool to room temperature, filter under reduced pressure, rinse the filter cake with ethanol, dry at -0.1 MPa, 50°C, pass through a silica gel column, and spin-dry the filtrate to obtain LA-092 (yield 42.6%).

[0177] HPLC purity: >99%.

[0178] Mass spectrometry test value: 1052.43.

[0179] Elemental Analysis:

[0180] Theoretical values: C, 67.69%; H, 4.25%; N, 2.43%; O, 5.55%; F, 1.56%

[0181] Test values: C, 67.70%; H, 4.26%; N, 2.44%; O, 5.56%; F, 1.57%.

[0182] H NMR spectrum:

[0183] 1 H NMR (400 MHz, deuterated chloroform) δ 8.82 (d, 2H), 8.15 (ddd, 2H), 8.01-7.78 (m, 10H), 7.75-7.63 (m, 6H), 7.47 (td, 2H), 7.40 (td, 2H), 7.25 (dtd, 2H), 5.65 (d, 1H), 2.67-2.52 (m, 2H), 1.79-1.39 (m, 20H).

[0184] Embodiment 7-20

[0185] According to the synthesis method in Example 1, only the corresponding reactants are replaced to synthesize the target compounds of Examples 7 to 20, and their specific structural chemical formulas and MS (i.e., mass spectrometry) results are shown in Table 1.

[0186] Table 1. Chemical formulas and MS results of target compounds of Examples 7 to 20

[0187]

[0188]

[0189] The organic light-emitting device provided in the application example of the present invention includes an anode, a cathode and an organic layer, wherein the organic layer at least includes a light-emitting layer, and the organic layer may further include at least one of a hole injection layer, a hole transport layer, a hole blocking layer, an electron injection layer, and an electron transport layer.

[0190] Application Example 1

[0191] In this application example 1, an organic electroluminescent device is prepared based on the iridium complex LA-001 prepared in Example 1, which includes the following layers stacked in sequence: glass / anode / hole injection layer / hole transport layer / electron blocking layer / luminescent layer / electron transport layer / electron injection layer / cathode.

[0192] The transparent conductive ITO glass substrate with an anode is treated in ultrasound, rinsed in deionized water, and then washed with ethanol, acetone and deionized water in sequence, baked in a clean environment until the water is completely removed, cleaned with ultraviolet photosynthetic ozone, and then treated with oxygen plasma for 30 seconds. First, CuPc is evaporated on the ITO (anode), followed by NPB, and the main material 4,4'-N,N'-biphenyl dicarbazole ("CBP") and the dopant compound LA-001 are mixed and evaporated, wherein the weight ratio of CBP to the dopant compound LA-001 is 95:5; the electron transport layer "Alq3" is evaporated, the electron injection layer LiF is evaporated, and the cathode Al is evaporated to prepare an organic electroluminescent device.

[0193] Referring to the above method, LA-001 was replaced by LA-002, LA-008, LA-013, LA-019, LA-022, LA-028, LA-046, LA-074, LA-077, LA-085, LA-092, LA-111, LA-143, LA-186, LA-194, LA-256, LA-334, LA-589, and LA-603, respectively, to prepare organic electroluminescent devices of the corresponding compounds.

[0194] Comparative Example

[0195] An organic electroluminescent device was prepared in the same manner as in Application Example 1, except that the dopant compound LA-001 of the organic light-emitting layer was replaced by compound RD, RD' or RD", and the structure of the obtained organic electroluminescent device, compound RD, RD', RD" was as follows:

[0196]

[0197]

[0198] The organic electroluminescent elements prepared in Examples 1 to 20 and Comparative Example RD, RD′, and RD″ were connected to an external power source, and the characteristics of the organic electroluminescent elements were evaluated at room temperature using a current source and a photometer.

[0199] Specifically, at 10 mA / cm 2 The driving voltage, external quantum efficiency (EQE), lifetime characteristics (LT95) and full width at half maximum (FWHM) were measured at currents of 2 , the results are shown in Table 2 below.

[0200] LT95 lifetime is the time it takes for a display element to lose 5% of its initial brightness. LT95 lifetime is the most difficult customer specification to meet and determines whether a display will experience image burn-in.

[0201] The full width at half maximum (FWHM) refers to the wavelength width corresponding to 1 / 2 of the maximum value of the curve (kr) representing the wavelength. A narrow FWHM means that a wide range of colors can be presented, thus meaning that colors closer to natural colors can be achieved and the color gamut can be improved.

[0202] Table 2. Test results of organic electroluminescent devices in Examples 1 to 20 and Comparative Example 1

[0203]

[0204] RD, RD' and RD" are doping compounds of the light-emitting layer in the comparative example of the present invention, and their structural differences from the compound represented by the chemical formula LA-001 in the embodiment of the present invention are that the substitution positions of the benzene rings in the ligand parent cores are different, and the number of substitutions of the benzene rings is also different.

[0205] From the results of Table 1 and Table 2, it can be seen that the driving performance of the organic electroluminescent element using the organic metal compound of Examples 1 to 20 of the present invention as the dopant of the light-emitting layer is reduced. Compared with the comparative example, the driving voltage is reduced, the external quantum efficiency (EQE) and life (LT95) are increased, and the color purity is improved due to the narrower full width at half maximum (FWHM).

[0206] The applicant declares that the present invention uses the above-mentioned embodiments to illustrate the phosphorescent complex and its preparation method and the organic electroluminescent device of the present invention, but the present invention is not limited to the above-mentioned embodiments, that is, it does not mean that the present invention must rely on the above-mentioned embodiments to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of various raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A phosphorescent complex, characterized in that: The phosphorescent complex has a structure shown in the following formula LA: wherein ring Ra and ring Rb independently represent absence or selection from unsubstituted C4-C12 aryl; R1 to R3 each independently represent hydrogen, deuterium, halogen, substituted or unsubstituted C1-C10 alkyl, substituted or unsubstituted C6-C24 cycloalkyl, substituted or unsubstituted C3-C30 heteroalkyl, substituted or unsubstituted C6-C24 aralkyl, substituted or unsubstituted C1-C15 alkoxy, substituted or unsubstituted C6-C24 aryloxy, substituted or unsubstituted C1-C3 silyl, substituted or unsubstituted C1-C3 germyl, ester, nitrile, isonitrile, thiol, sulfinyl, sulfonyl, phosphino, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C6-C30 heteroaryl; R4 to R7 represent substitutions at any position on the ring where they are located, and the substituents are selected from hydrogen, deuterium, halogen, substituted or unsubstituted C1-C10 alkyl, substituted or unsubstituted C6-C24 cycloalkyl, substituted or unsubstituted C3-C30 heteroalkyl, substituted or unsubstituted C6-C24 aralkyl, substituted or unsubstituted C1-C15 alkoxy, substituted or unsubstituted C6-C24 aryloxy, substituted or unsubstituted C1-C3 silyl, substituted or unsubstituted C1-C3 germyl, ester, nitrile, isonitrile, thio, sulfinyl, sulfonyl, phosphino, substituted or unsubstituted C6-C12 aryl, substituted or unsubstituted C6-C12 heteroaryl; The substituents in the above-mentioned substituted groups can be selected from one or a combination of at least two of the following groups: deuterium, fluorine, methyl, ethyl, propyl, isopropyl, butyl, tert-butyl, isobutyl, pentyl, isopentyl, neopentyl, hexyl, 2-methylpentyl, 3-methylpentyl, 2,3-dimethylbutyl, 2,2-dimethylbutyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, methoxy, ethoxy, propoxy, phenoxy, C1-C3 silanyl, C1-C3 germanyl, ester group, nitrile group, isonitrile group, sulfide group, sulfinyl group, sulfonyl group, and phosphine group.

2. The phosphorescent complex according to claim 1, characterized in that Ring Ra and ring Rb independently represent absence or selection from a benzene ring or a naphthalene ring.

3. The phosphorescent complex according to claim 1, characterized in that R1 to R7 are each independently selected from methyl, ethyl, propyl, isopropyl, halogen, deuterium, butyl, tert-butyl, isobutyl, At least one of a trimethylsilyl group, a cyclohexyl group, a cyano group, or a substituted or unsubstituted benzene ring.

4. The phosphorescent complex according to claim 1, characterized in that The phosphorescent complex is any one of the following complexes:

5. An organic electroluminescent device, characterized in that: The organic electroluminescent device comprises a first electrode, a second electrode and at least one organic layer, wherein the organic layer is located between the first electrode and the second electrode, and at least one organic layer comprises the phosphorescent complex according to any one of claims 1 to 4.

6. The organic electroluminescent device according to claim 5, characterized in that: The organic layer at least includes a hole injection layer, a hole transport layer, a layer having both hole injection and hole transport skills, an electron blocking layer, a light-emitting layer, a hole blocking layer, an electron transport layer, an electron injection layer and a layer having both electron transport and electron injection skills, or a combination of at least two of them.

7. The organic electroluminescent device according to claim 6, characterized in that: The light-emitting layer comprises a host material and a doping material, wherein the host material comprises a fluorescent host and a phosphorescent host, and the doping material is the phosphorescent complex according to any one of claims 1 to 5.

8. The organic electroluminescent device according to claim 7, characterized in that: The mixing ratio of the main material to the doping material is (85:15) to (99:1).

9. Use of the organic electroluminescent device according to any one of claims 5 to 9 in a display device or a light-emitting device.

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