A spirofluorene metal platinum complex containing N heteroatom and its electroluminescent device

Abstract

The present invention belongs to the field of organic light-emitting materials and semiconductor technology, and provides a spirofluorene metal platinum complex containing N heteroatom and an electroluminescent device thereof. The structure of the spirofluorene metal platinum complex containing N heteroatom is shown in formula (1): The electroluminescent device of the present invention uses the spirofluorene metal platinum complex containing N heteroatom as the guest light-emitting material in the light-emitting layer, which can not only emit blue light, but also has a good improvement in light-emitting efficiency and life.

Description

Technical Field

[0001] The invention belongs to the technical field of organic luminescent materials and semiconductors, and in particular relates to a spirofluorene metal platinum complex containing N heteroatoms and an electroluminescent device thereof. Background Art

[0002] Compared with liquid crystal displays (LCDs), organic light emitting diodes (OLEDs) have the advantages of being foldable or bendable, self-luminous, high contrast, wide operating temperature range, low material cost, high luminous efficiency, and low power consumption. With the breakthrough of OLED technology barriers and the reduction of costs, OLED displays will become the mainstream in the future display field.

[0003] The design and development of luminescent materials is the core of the OLED field. Traditional fluorescent luminescent materials can use up to 25% of singlet excitons, and the remaining 75% of triplet excitons will be inactivated due to transition inhibition. Phosphorescent materials with heavy atom effects can make full use of singlet and triplet excitons, and theoretically can achieve 100% utilization of excitons, providing broad space for the future development of high-efficiency luminescent materials. Phosphorescent materials play a decisive role in the efficiency of phosphorescent electroluminescent devices. The performance of electroluminescent devices can be adjusted by designing different types of organic ligands in phosphorescent materials.

[0004] At present, most of the phosphorescent materials that can meet commercial applications are cyclometallated iridium (III) complex phosphorescent materials, but metallic iridium is expensive and limited in quantity. The abundance of metallic platinum in the earth's crust is much higher than that of iridium, and metallic platinum is relatively cheap. In addition, the total yield of cyclometallated iridium (III) complex phosphorescent materials is low. In contrast, the utilization rate of platinum is high in the preparation process of cyclometallated platinum (II) complex phosphorescent materials. Therefore, the preparation cost of cyclometallated platinum (II) complex phosphorescent materials is much lower than that of cyclometallated iridium (III) complex phosphorescent materials.

[0005] Usually, metal platinum (II) and ligands can form cyclometal platinum (II) complexes using bidentate ligands, tridentate ligands or tetradentate ligands, but cyclometal platinum (II) complexes with bidentate ligands and tridentate ligands have lost their use value due to the instability of the compounds themselves. In contrast, the rigid molecular structure of cyclometal platinum (II) complexes based on tetradentate ligands can inhibit vibration coupling and reduce non-radiative transitions, thereby improving quantum efficiency; at the same time, tetradentate ligands have high chemical and thermal stability, making them ideal ligands for the development of new OLED phosphorescent materials.

[0006] Conventional OLED devices need materials that emit red, green and blue light to achieve full-color display. However, compared with red and green light-emitting materials, excellent blue light-emitting materials are relatively scarce, especially high-efficiency blue light phosphorescent material molecules with stable structure and suitable emission spectrum, which have greater commercial value.

[0007] US patent application publication number US 2020 / 0168817 A1 reports tetradentate ligand cyclometallated platinum complexes , The cyclometalated platinum complex is an excellent blue light phosphorescent material. When it is used as a guest material in the light-emitting layer of an OLED device, the OLED device exhibits a shorter emission wavelength, but has a lower luminous efficiency and a shorter service life.

[0008] Therefore, designing and developing blue light phosphorescent materials with long lifetime and high luminescence efficiency has been a long-term goal of development in this field. Summary of the invention

[0009] In order to solve the above problems of the prior art, the present invention provides a spirofluorene metal platinum complex containing N heteroatom and an electroluminescent device thereof, which improves the luminous efficiency and service life of the electroluminescent device.

[0010] The present invention is achieved through the following technical solutions:

[0011] The present invention provides a spirofluorene metal platinum complex containing a N heteroatom, the structure of which is shown in formula (1):

[0012]

[0013] Where:

[0014] A is selected from substituted or unsubstituted C3~C 15 N-containing heteroaryl; B is selected from substituted or unsubstituted C 12 ~C 30 an aryl group and a substituted or unsubstituted C 12 ~C 30 The heteroaryl group.

[0015] Z1 and Z2 are independently a C atom or a N atom, and Z1 and Z2 are not N atoms at the same time;

[0016] A through C3~C 15 The N-containing heteroaryl is bonded to the main structure, and B is bonded to the main structure in a spiro-carbon manner; the main structure is .

[0017] Preferably, in the spirofluorene metal platinum complex containing a N heteroatom, the substituted or unsubstituted C3~C 15 The N-containing heteroaryl group refers to the C3~C15 The N-containing heteroaryl group may be further substituted by a substituent or may not be substituted by a substituent; when the C3~C 15 When the N-containing heteroaryl is substituted by a substituent, the substituent is selected from methyl and phenyl.

[0018] Preferably, in the spirofluorene metal platinum complex containing a N heteroatom, the substituted or unsubstituted C 12 ~C 30 The aryl group refers to the C 12 ~C 30 The aryl group may be further substituted by a substituent or may not be substituted by a substituent; when the C 12 ~C 30 When the aryl group is substituted by a substituent, the substituent is selected from a methyl group and an oxy group.

[0019] Preferably, in the spirofluorene metal platinum complex containing a N heteroatom, the substituted or unsubstituted C 12 ~C 30 The heteroaryl group refers to the C 12 ~C 30 The heteroaryl group may be further substituted by a substituent or may not be substituted by a substituent; when the C 12 ~C 30 When the heteroaryl group is substituted by a substituent, the substituent is selected from methyl, isopropyl, phenyl and oxy.

[0020] In the present invention, the term "aryl" refers to an all-carbon monocyclic or fused polycyclic (ie, rings that share adjacent pairs of carbon atoms) group having a conjugated π electron system.

[0021] In the present invention, the term "heteroaryl" refers to a general term for groups in which one or more aromatic carbon atoms or non-aromatic carbon atoms in an aromatic group are replaced by heteroatoms, wherein the heteroatoms include but are not limited to oxygen, sulfur, nitrogen, silicon, germanium, selenium, boron, arsenic or phosphorus atoms, and the heteroaryl group may be a monocyclic heteroaryl group, a polycyclic heteroaryl group or a condensed-ring heteroaryl group.

[0022] Preferably, in the spirofluorene metal platinum complex containing a N heteroatom, the A is selected from one of the following groups Y1 to Y13:

[0023] .

[0024] In the groups Y1 to Y13, " indicates the bonding position between A and the Pt atom in the main structure. The " ” indicates the bonding position of A to the benzene ring in the main structure.

[0025] Preferably, in the spirofluorene metal platinum complex containing a N heteroatom, B is selected from one of the following groups R1 to R17:

[0026]

[0027] In the groups R1 to R17, " is the bonding position between B and the main structure, and R in the group R17 is selected from phenyl, m-methylphenyl and p-methylphenyl.

[0028] Preferably, the spirofluorene metal platinum complex containing a N heteroatom is selected from one of the following compounds 1 to 316:

[0029]

[0030] The present invention also provides an electroluminescent device, comprising a cathode, an anode and an organic layer located between the cathode and the anode, wherein the organic layer comprises a hole transport layer, a light-emitting layer and an electron transport layer, wherein the hole transport layer is located between the anode and the light-emitting layer, and the electron transport layer is located between the cathode and the light-emitting layer; the components of the light-emitting layer include a host light-emitting material and a guest light-emitting material, wherein the guest light-emitting material comprises a spirofluorene metal platinum complex containing a N heteroatom as shown in formula (1).

[0031] Preferably, the mass of the guest luminescent material accounts for 0.5% to 3% of the mass of the entire luminescent layer, and more preferably 2%.

[0032] Preferably, the host light-emitting material includes a first host material and a second host material, and the mass ratio of the first host material to the second host material is in the range of (40~60):(40~60).

[0033] Preferably, the first host material is selected from any one of the following RH1-1 to RH1-4:

[0034] .

[0035] Preferably, the second main material is selected from any one of the following RH2-1 to RH2-4:

[0036] .

[0037] Preferably, a substrate may be disposed outside the anode or cathode, and the substrate may be glass or a polymer material having excellent mechanical strength, thermal stability, water resistance, and transparency. In addition, the substrate used as a display may also have a thin film transistor (TFT) array and a specific display image formed by the combination of the thin film transistor array.

[0038] The anode can be obtained by sputtering or depositing a specific functional layer material on a substrate, and the functional layer material can be an oxide transparent conductive material such as indium tin oxide (ITO), indium zinc oxide (IZO), tin dioxide (SnO2), zinc oxide (ZnO) and any combination thereof. The cathode can be a metal single substance or alloy with good electrical conductivity. Preferably, the cathode can be magnesium (Mg), silver (Ag), aluminum (Al), aluminum-lithium (Al-Li), calcium (Ca), magnesium-indium (Mg-In), magnesium-aluminum (Mg-Al) and any combination thereof.

[0039] Preferably, the organic layer can be formed on the hole transport layer by vacuum thermal evaporation, spin coating or inkjet printing.

[0040] The hole transport layer of the present invention can be a single-layer hole transport layer (HTL), that is, it only contains one hole transport material (a hole transport layer that has both hole injection function and hole transport effect), or it can be a composite hole transport layer containing multiple compounds. The composite hole transport layer is mainly an organic combination of a hole injection layer (HIL) and a hole transport layer in a common industry arrangement.

[0041] The electroluminescent device of the present invention is applied to the fields of luminous illumination, image display or photoelectric signal transmission.

[0042] Compared with the prior art, the present invention has the following beneficial effects:

[0043] The spirofluorene metal platinum complex containing N heteroatom provided by the present invention has a strong spin-orbit coupling effect between the singlet and triplet states of the complex molecule, thereby enhancing the intra-molecule intersystem crossing (ISC) capability, showing the potential of utilizing singlet excitons and triplet excitons at the same time, so that the internal quantum efficiency can reach 100%, thereby improving the luminous efficiency of the electroluminescent device. At the same time, the spirofluorene metal platinum complex containing N heteroatom of the present invention introduces a spirocyclic B-containing N-fluorene group and its derivatives with a large volume and rigid structure. Such a design is conducive to inhibiting molecular stacking, reducing intermolecular interactions, and further reducing triplet-triplet annihilation (Triplet-triplet Annihilation, TTA), thereby improving the external quantum efficiency of the electroluminescent device and extending the service life of the electroluminescent device, and can inhibit the red shift of the spectrum, while achieving high luminous efficiency and long service life while emitting blue light. In addition, the molecules of the spirofluorene metal platinum complex containing N heteroatoms of the present invention have a spatial cross conformation, and such a structural design is conducive to improving its solubility in organic solvents, and can effectively improve the poor solubility of the metal complex. Such materials are expected to be used in the preparation of OLED flexible display screens. The spirofluorene metal platinum complex containing N heteroatoms provided by the present invention has the characteristics of narrow-band luminescence, can be used as a blue light phosphorescent material in an electroluminescent device, and can effectively improve the color purity of the electroluminescent device.

[0044] Furthermore, when the B group in the N-heteroatom-containing spirofluorene metal platinum complex of the present invention contains an electron-withdrawing group, its emission wavelength can be blue-shifted, so that an electroluminescent device with bluer emission light can be obtained based on the N-heteroatom-containing spirofluorene metal platinum complex.

[0045] The electroluminescent device of the present invention uses the spirofluorene metal platinum complex containing N heteroatom as the guest luminescent material in the luminescent layer, which can not only emit blue light, but also has a good improvement in luminous efficiency and life. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0047] Figure 1 is a cross-sectional view of an electroluminescent device of the present invention;

[0048] Explanation of the reference numerals: 1. substrate, 2. anode, 3. hole injection layer, 4. hole transport layer, 5. light-emitting layer, 6. electron transport layer, 7. electron injection layer, 8. cathode. DETAILED DESCRIPTION

[0049] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0050] It should be noted that the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products or apparatus.

[0051] The specific implementation modes of the present invention are described below in conjunction with the examples. The raw materials and reagents used in the present invention are all commercially available.

[0052] The structures of the intermediates (L series intermediates L1-L13 and M series intermediates M1-M53) involved in the present invention are shown in Table 1 below.

[0053] Table 1 The important intermediate structures involved in the present invention

[0054]

[0055] Among them, the synthesis process of some intermediates is as follows:

[0056] Intermediate L1:

[0057]

[0058] Operation process:

[0059] Under argon protection, 1,3-dibromobenzene (236 g, 1.0 mol), imidazole (68 g, 1.0 mol), CuI (19 g, 0.1 mol), K2CO3 (276 g, 2.0 mol), ligand (trans-1,2-cyclohexanediamine) (23 g, 0.2 mol) and 2.5 L of dimethyl sulfoxide (DMSO) were added to a 5 L three-necked flask, and refluxed at 110 ° C for 72 h, and then cooled to room temperature. The resulting reaction solution was filtered through diatomaceous earth, and the filter cake was washed with ethyl acetate. After the filtrate was concentrated, it was passed through a silica gel column with n-hexane and ethyl acetate to obtain intermediate L1, weighing 134 g, as a light brown oil, with a yield of 60.2%, a GC (gas chromatography, Gas Chromatography) purity of 98%, and a GC-MS (gas chromatography-mass spectrometry) showing a molecular weight of 222.0.

[0060] Intermediate L2:

[0061]

[0062] Operation process: The synthesis process of intermediate L2 is consistent with that of intermediate L1, except that imidazole is replaced with benzimidazole (1 g, 1.0 mol) to obtain intermediate L2, weighing 168 g, as a light brown oil, with a yield of 61.5%, a GC purity of 98%, and a molecular weight of 272.0 as shown by GC-MS.

[0063] The synthesis of intermediates L3 to L11 all refer to the synthesis of intermediate L1, and the synthesis process will not be repeated here.

[0064] Synthesis of intermediate L12:

[0065]

[0066] Operation process:

[0067] Under argon protection, m-bromoiodobenzene (71 g, 0.3 mol), benzoxazole (43 g, 0.36 mol), Pd(dppf)Cl2 .CH2Cl2 (12.2 g, 0.015 mol), PPh3 (7.9 g, 0.03 mol), Ag2CO3 (165 g, 0.6 mol) and acetonitrile 1.0 L were refluxed at 65 ° C for 96 h and then cooled to room temperature. The reaction solution was filtered through diatomaceous earth and the filter cake was washed with ethyl acetate. After concentrating the filtrate, it was passed through a silica gel column with n-hexane and ethyl acetate to obtain intermediate L12, weighing 49 g, a light brown solid, with a yield of 59.3%, a GC purity of 98%, and a molecular weight of 272.9 according to GC-MS.

[0068] The synthesis of intermediate L13 refers to the synthesis of intermediate L12, and the synthesis process is not repeated here.

[0069] Synthesis of intermediate M1:

[0070]

[0071] Synthesis of intermediate M1-1:

[0072] Operation process: take a 10L three-necked flask, add 2-bromophenanthroline (118g, 0.5mol) and 2.5L of 0.2mol / L KOH aqueous solution, reflux reaction for 1h, wait until the solution cools to room temperature, then slowly add 1.5L of 0.03mol / L potassium permanganate (KMnO4) aqueous solution, and the reaction solution refluxes for 2h. After the reaction is completed, the reaction solution is heated and filtered, and the filtrate is cooled to room temperature. When a large amount of needle-shaped crystals are precipitated, filter. The filtrate is extracted three times with chloroform, and the organic phase is combined. Concentrate the organic phase to obtain a yellow solid, which is the intermediate M1-1, weighing 66g, with a yield of 50.3%, HPLC (High Performance Liquid Chromatography) purity 98%, and LC-MS (Liquid Chromatograph-Mass Spectrometer) shows a molecular weight of 260.9.

[0073] Synthesis of intermediate M1-2:

[0074] Operation process: Under argon protection, take a 1000mL three-necked flask, add 2-iodo-biphenyl (62g, 0.22mol) and THF (tetrahydrofuran) 200mL, stir and cool to -95℃, drop 200mL of n-butyl lithium (n-BuLi, 2.0mol / L) into the system, keep warm at -95℃ for 1h, then slowly drop 100mL of intermediate M1-1 (52g, 0.2mol) THF solution into the above system, keep warm for 0.5h after the addition, then naturally warm to room temperature, add 10mL of water to quench, and the reaction is complete. When the reaction solution is concentrated to a small amount of THF under reduced pressure, add 200mL of toluene and 150mL of water, stir and wash with water, separate the liquids, wash the organic phase with water until neutral and dry it with anhydrous magnesium sulfate. After drying, the organic phase was filtered and collected, transferred to another 500mL three-necked flask, and methylsulfonic acid (38.5g, 0.4mol) was slowly added dropwise under stirring, and the reaction was continued at room temperature for 2h until the reaction was completed. Then 150mL of water was added to quench, the organic phase was separated, and then washed with water in small amounts several times until neutral, the organic phase was concentrated under reduced pressure, and 150mL of n-heptane was used to reflux, boil and disperse, and then cooled to room temperature and filtered, and the off-white solid was dried to obtain the intermediate M1-2, weighing 61g, HPLC content 99%, yield 76.2%, LC-MS molecular weight 397.0.

[0075] Synthesis of intermediate M1:

[0076] Operation process: Under argon protection, take a 1000mL three-necked flask, add intermediate M1-2 (60g, 0.15mol), CuI (0.29g, 1.5mmol), ligand 8-hydroxy-2-methylquinoline (0.48g, 3mmol), tetrabutylammonium hydroxide pentahydrate (157g, 0.45mol), DMSO (dimethyl sulfoxide) 200mL and water 300mL, reflux at 130℃ for 14h until the reaction is complete, wait for the reaction solution to cool to room temperature, extract the reaction solution three times with 900mL ethyl acetate (300mL each time), and combine the organic phases. Concentrate the organic phase and recrystallize with ethyl acetate-n-heptane to obtain an off-white solid M1, weighing 46g, with a yield of 92.4%, HPLC purity of 99%, and LC-MS showing a molecular weight of 335.1.

[0077] Synthesis of intermediate M2:

[0078]

[0079] Synthesis of intermediate M2-1:

[0080] Operation process: take a 2000mL three-necked flask, add methanesulfonic acid (192g, 2.0mol), stir, slowly drip 300mL of o-dichlorobenzene solution containing intermediate M1-1 (52g, 0.2mol), after the addition is complete, stir at room temperature for 1h, and then slowly drip 600mL of o-dichlorobenzene solution containing phenol (94.11g, 1.0mol), after the addition is complete, react at 35℃ for 2h, heat to 150℃, react for 24h until the reaction is complete, concentrate the reaction solution and pass it through column chromatography to obtain intermediate M2-1, weighing 41g, off-white solid, yield 49.9%, HPLC purity 98%, LC-MS shows molecular weight 412.9.

[0081] Synthesis of intermediate M2:

[0082] Operation process: The synthesis process of intermediate M2 is consistent with that of intermediate M1, except that intermediate M1-2 is replaced by intermediate M2-1 (41 g, 0.1 mol) to obtain intermediate M2, weighing 30 g, off-white solid, with a yield of 89.6%, HPLC purity of 99%, and LC-MS showing a molecular weight of 335.1.

[0083] Synthesis of intermediate M3:

[0084]

[0085] Synthesis of intermediate M3-1:

[0086] Operation process: The synthesis process of intermediate M3-1 is consistent with that of intermediate M1-2, except that 2-iodo-biphenyl is replaced by (2-bromophenyl)(phenyl)sulfide (58 g, 0.22 mol) to obtain intermediate M3-1, weighing 65 g, off-white solid, with a yield of 75.9%, HPLC purity of 99%, and LC-MS showing a molecular weight of 430.2.

[0087] Synthesis of intermediate M3:

[0088] Operation process: The synthesis process of intermediate M3 is consistent with that of intermediate M1, except that intermediate M1-2 is replaced by intermediate M3-1 (43 g, 0.1 mol) to obtain intermediate M3, weighing 33 g, off-white solid, with a yield of 90.3%, HPLC purity of 99%, and LC-MS showing a molecular weight of 367.1.

[0089] Synthesis of intermediate M35:

[0090]

[0091] Synthesis of intermediate M35-1:

[0092] Operation process: Under argon protection, take a 5000mL three-necked flask, add 2-chloropyrazine (115g, 1.0mol), o-nitroboronic acid pinacol ester (262g, 1.05mol), Pd(PPh3)4 (11.6g, 0.01mol), K2CO3 (276g, 2.0mol), THF2000mL and water 500mL, heat to 80℃, react for 15 hours until the reaction is complete, cool down, distill most of THF at low temperature under reduced pressure, add 800mL water and 2000mL ethyl acetate for extraction, dry the obtained organic phase, and distill under reduced pressure. The obtained residue is purified by silica gel column chromatography to obtain intermediate M35-1, weighing 152g, brown oil, with a yield of 75.4%, GC purity of 98%, and GC-MS showing a molecular weight of 200.9.

[0093] Synthesis of intermediate M35-2:

[0094] Operation process: Take a 5000mL three-necked flask, add intermediate M35-1 (151g, 0.75mol), 80% hydrazine hydrate (187g, 3.0mol), catalyst Co3O4@Al2O3 / SiO2 (6g, 0.015 mol) and 2000mL EtOH, and stir at 60℃ for 2h until the reaction is complete. Filter the reaction solution, evaporate the filtrate to semi-dryness, add 800mL water and 1000mL dichloromethane for extraction, dry the organic phase, concentrate, and purify the residue by silica gel column chromatography to obtain intermediate M35-2, weighing 112g, brown oil, yield 87.2%, GC purity 98%, GC-MS shows molecular weight 170.9.

[0095] Synthesis of intermediate M35-3:

[0096] Operation process: Under argon protection, take a 5000mL three-necked flask, add intermediate M35-2 (111g, 0.65mol), NBS (N-bromosuccinimide, N-Bromosuccinimide) (236g, 0.72mol), 1500mL chloroform and 1500mL glacial acetic acid. React at room temperature for 15h until the reaction is complete, pour the reaction solution into 2000mL deionized water, and extract with dichloromethane several times. Combine the organic phases, dry with anhydrous sodium sulfate, and distill under reduced pressure. The resulting residue is purified by silica gel column chromatography to obtain intermediate M35-3, weighing 139g, brown oil, yield 85.4%, GC purity 98%, GC-MS shows molecular weight 248.9.

[0097] Synthesis of intermediate M35-4:

[0098] Operation process: Under argon protection, take a 3000mL three-necked flask, add intermediate M35-3 (138g, 0.55mol) and 1000mL of 50% hydrochloric acid aqueous solution, cool to below 0℃ in an ice-salt bath, slowly add 200mL of sodium nitrite (42g, 0.61mol) aqueous solution, react for 0.5h after the addition is complete, remove the ice-salt bath, slowly add 200mL of potassium iodide (100g, 0.61mol) aqueous solution, react at 30℃ for 1h after the addition is complete until the reaction is complete. Take 3000mL of dichloromethane to extract the reaction solution three times, each time using 1000mL, combine the organic phases, dry, concentrate, and pass through a silica gel column to obtain intermediate M35-4, weighing 130g, brown oil, with a yield of 65.3%, GC purity of 98%, and GC-MS showing a molecular weight of 359.8.

[0099] Synthesis of intermediate M35-5:

[0100] Operation process: The synthesis process of intermediate M35-5 is consistent with that of intermediate M1-2, except that intermediate M1-1 is replaced by intermediate M35-4 (79 g, 0.22 mol), and 2-iodo-biphenyl is replaced by 9-fluorenone (36 g, 0.2 mol) to obtain intermediate M35-5, weighing 58 g, brown solid, with a yield of 73.2%, HPLC purity of 98%, and LC-MS showing a molecular weight of 396.9.

[0101] Synthesis of intermediate M35:

[0102] Operation process: The synthesis process of intermediate M35 is consistent with that of intermediate M1, except that intermediate M1-2 is replaced by intermediate M35-5 (40 g, 0.1 mol) to obtain intermediate M35, weighing 30 g, brown solid, with a yield of 89.6%, HPLC purity of 99%, and LC-MS showing a molecular weight of 335.0.

[0103] Synthesis of intermediate M18:

[0104]

[0105] Synthesis of intermediate M18-1:

[0106] Operation process: The synthesis process of intermediate M18-1 is consistent with that of intermediate M1-2, except that intermediate M1-1 is replaced by 8-chloro-5H-indeno[1,2-b]pyridine-5-one (43 g, 0.2 mol) to obtain intermediate M18-1, weighing 52 g, light brown solid, with a yield of 73.6%, HPLC purity of 98%, and LC-MS showing a molecular weight of 352.0.

[0107] Synthesis of intermediate M18:

[0108] Operation process: The synthesis process of intermediate M18 is consistent with that of intermediate M1, except that intermediate M1-2 is replaced by intermediate M18-1 (35 g, 0.1 mol) to obtain intermediate M18, weighing 30 g, light brown solid, with a yield of 89.9%, HPLC purity of 99%, and LC-MS showing a molecular weight of 334.0.

[0109] The synthesis of other M series intermediates can refer to the synthesis process of the above intermediates.

[0110] Using the above key intermediates, the synthesis implementation process of the preferred compound 1 and compound 105 is exemplified as follows:

[0111] Synthesis of compound 1:

[0112]

[0113] Synthesis of intermediate 1-1:

[0114] Operation process: Under argon protection, take a 1000mL dry three-necked flask, add intermediate M1 (67g, 0.2mol), intermediate L1 (45g, 0.2mol), CuI (3.8g, 0.02mol), picolinic acid (4.9g, 0.04mol), K3PO4 (127g, 0.6mol) and DMSO (400mL). Stir the mixture in an oil bath at 100°C for 3 days and then cool to room temperature. Add water (500mL) and stir, extract the mixture three times with ethyl acetate, combine the organic phases, wash the organic phases three times with distilled water, then dry with anhydrous sodium sulfate, filter, concentrate, and purify the residue by silica gel column chromatography (solvent: toluene / n-heptane) to obtain intermediate 1-1, a light brown solid, weighing 38g, with a yield of 39.6%, HPLC purity of 97%, and LC-MS showing a molecular weight of 477.1.

[0115] Synthesis of intermediate 1-2:

[0116] Operation process: Take a 500mL sealed container, quickly add intermediate 1-1 (38g, 0.08mol), toluene (200mL), CH3I (6.0mL, 0.096mol), seal, and stir the reaction solution at 100℃ for 2 days until the reaction is complete. The reaction solution is cooled to room temperature, and the solvent is removed by vacuum distillation. The residue is purified by silica gel column chromatography (solvent: toluene / n-heptane) to obtain a brown solid (39g), which is directly used in the next step. The brown solid is added to a mixture of methanol-water (120mL / 80mL) and stirred until the solid is completely dissolved. Then NH4PF6 (14g, 0.088mol) is added to the solution. The reaction solution is stirred at room temperature (rt) for 3 days and then diluted with deionized water. Filter, wash the filter cake with H2O and Et2O, and dry to obtain intermediate 1-2, weighing 28.4g, light brown solid, with a total yield of 72.3%, HPLC purity of 98%, and LC-MS showing a molecular weight of 637.1.

[0117] Synthesis of compound 1:

[0118] Operation process: Take a 100mL pressure vessel, add intermediate 1-2 (13g, 0.02mmol), catalyst Pt(COD)Cl2 (3.4g, 0.021mmol), NaOAc (9.8g, 0.06 mmol), acetonitrile (50mL), fill with nitrogen and quickly seal, heat the reaction system to 120℃, stir for 44h until the reaction is complete, and cool the reaction solution to room temperature. The solvent is removed by vacuum distillation, and the residue is purified by silica gel column chromatography (solvent: toluene / n-heptane) to obtain compound 1, weighing 6.2g, with a yield of 45.3%. At 3.0×10 -6 Under the condition of 2000 ℃ and 8000 ℃, 6.2 g of the product was further purified by sublimation in a four-zone thermal gradient sublimator (280℃, 275℃, 190℃, 150℃) to obtain 5.4 g of yellow solid with a yield of 86.9%, HPLC purity of 99%, and LC-MS showing a molecular weight of 686.0.

[0119] Synthesis of compound 105:

[0120]

[0121] Synthesis of intermediate 105-1:

[0122] Operation process: The synthesis process of intermediate 105-1 is consistent with that of intermediate 1-1, except that intermediate L1 is replaced by intermediate L3 (45 g, 0.2 mol), and intermediate M1 is replaced by intermediate M3, to obtain intermediate 105-1, weighing 37 g, light brown solid, with a yield of 38.9%, HPLC purity of 98%, and LC-MS showing a molecular weight of 476.2.

[0123] Synthesis of compound 105:

[0124] Operation process: The synthesis process of compound 105 is consistent with that of compound 1, except that intermediate 1-2 is replaced by intermediate 105-1 (10 g, 0.02 mmol) to obtain compound 105, weighing 6.0 g, with a yield of 44.8%; after sublimation purification, 5.2 g of yellow solid was obtained, with a yield of 87.5%, HPLC purity of 99%, and LC-MS showing a molecular weight of 669.0.

[0125] The synthesis processes of other compounds all refer to the synthesis processes of compound 1 and compound 105. The reactants involved in the reaction process of the compounds of the present invention are shown in Table 2.

[0126] Table 2 Reactants involved in the reaction process of the compounds of the present invention

[0127]

[0128] Table 3 Test results of some compounds of the present invention

[0129]

[0130] Based on the above-mentioned spirofluorene metal platinum complex containing N heteroatom of the present invention, an electroluminescent device is prepared, wherein the spirofluorene metal platinum complex containing N heteroatom is used as a guest luminescent material in the electroluminescent device.

[0131] The schematic diagram of the structure of the electroluminescent device used in the experimental process of the present invention is as follows Figure 1 As shown, it comprises a substrate 1, an anode 2, a hole injection layer 3, a hole transport layer 4, a light-emitting layer 5, an electron transport layer 6, an electron injection layer 7 and a cathode 8. The spirofluorene metal platinum complex containing a N heteroatom is used in the light-emitting layer as a guest light-emitting material to evaluate the performance of the electroluminescent device.

[0132] In the embodiment of the present invention, after the preparation of the above-mentioned main functional layers is completed, the electroluminescent device is packaged using the packaging device method currently commonly used in the industry, and the electroluminescent device is prepared into a 30mm×30mm sample, and then the various luminescence performance indicators of the above-mentioned sample are tested.

[0133] Comparative Example 1

[0134] The electroluminescent device was prepared as follows:

[0135] Under high vacuum conditions, indium tin oxide with a thickness of 25nm is deposited as an anode, F4CNQ with a thickness of 20nm is deposited as a hole injection layer, and NPD with a thickness of 120nm is deposited as a hole transport layer on the cleaned substrate conductive glass. After the hole transport layer is deposited, a light-emitting layer with a film thickness of 40nm is prepared. The light-emitting layer includes a main light-emitting material formed by a composite of RH1-3 and RH2-2, and a traditional phosphorescent material FIrtaz with excellent performance is used as a guest light-emitting material. RH1-3, RH2-2, and the guest light-emitting material are co-deposited at a mass ratio of 40:60:2 to form a light-emitting layer. On the light-emitting layer, BCP is deposited as an electron transport layer, and the vacuum-deposited film thickness of the material is 26nm. On the electron transport layer, a LiF layer with a film thickness of 16nm is prepared by a vacuum evaporation device. This layer is an electron injection layer. On the electron injection layer, a 50nm thick Mg-Al (molar ratio Mg:Al=1:9) electrode layer is produced by vacuum sputtering technology. This layer is the cathode. Finally, the obtained electroluminescent device is packaged after evaporating the covering layer material to complete the preparation process of the electroluminescent device.

[0136] Comparative Example 2

[0137] An electroluminescent device was prepared according to the steps of Comparative Example 1, except that the guest luminescent material FIrtaz in the luminescent layer was replaced by FIrN4.

[0138] Comparative Example 3

[0139] An electroluminescent device was prepared according to the steps of Comparative Example 1, except that the guest luminescent material FIrtaz in the luminescent layer was replaced by the comparative document compound 1.

[0140] The detailed structures of the electroluminescent devices of Comparative Examples 1 to 3 are as follows:

[0141] Comparative Example 1: Conductive glass / indium tin oxide (25nm) / F4CNQ (20nm) / NPD (120nm) / RH1-3:RH2-2:FIrtaz =40:60:2 (40nm) / BCP (26nm) / LiF (16nm) / Mg-Al (50nm);

[0142] Comparative Example 2: Conductive glass / indium tin oxide (25nm) / F4CNQ (20nm) / NPD (120nm) / RH1-3:RH2-2:FIrN4 =40:60:2 (40nm) / BCP (26nm) / LiF (16nm) / Mg-Al (50nm);

[0143] Comparative Example 3: Conductive glass / indium tin oxide (25nm) / F4CNQ (20nm) / NPD (120nm) / RH1-3:RH2-2: Comparative document compound 1 = 40:60:2 (40nm) / BCP (26nm) / LiF (16nm) / Mg-Al (50nm).

[0144] The structure of the guest luminescent material involved in the above comparative example is as follows:

[0145]

[0146] Embodiment 1~10:

[0147] The preparation method of Comparative Example 1 was followed, except that the guest luminescent material FIrtaz in the luminescent layer was replaced in sequence with the spirofluorene metal platinum complex containing N heteroatom described in the present invention: Compound 105, Compound 56, Compound 58, Compound 59, Compound 99, Compound 100, Compound 101, Compound 298, Compound 299, and Compound 300.

[0148] The electroluminescent devices of Examples 1 to 10 and Comparative Examples 1 to 3 were tested, and the test data are shown in Table 4.

[0149] Table 4 Electroluminescent device test data

[0150]

[0151] Note: EQE refers to the external quantum efficiency of electroluminescent devices, T95 refers to the current density at 20mA / cm 2 The decay time of an electroluminescent device from its initial maximum brightness to 95% brightness under certain conditions.

[0152] As shown in Table 4, by comparing Example 1 with Comparative Example 3, it can be seen that the electroluminescent device prepared by using the spirofluorene metal platinum complex containing N heteroatom of the present invention (Compound 105) as the guest luminescent material has a lower starting voltage, an EQE increased by more than 30%, and a lifespan extended by more than 2 times compared with the electroluminescent device prepared by using the comparative document Compound 1 as the guest luminescent material. This indicates that the compounds of the present invention introduce a large volume rigid structure of the spirocyclic B-N-containing fluorene group and its derivatives, which can reduce intermolecular interactions and thus reduce triplet-triplet annihilation, thereby improving the external quantum efficiency of the electroluminescent device and extending the service life of the electroluminescent device.

[0153] Comparing Examples 1 to 10 with Comparative Examples 1 to 3, the electroluminescent devices prepared by using the preferred compounds of the present invention as the guest luminescent materials have significantly lower driving voltages, significantly narrower half-peak widths, increased EQE by about 40%, and extended lifetimes by about 2 times, compared with the electroluminescent devices of Comparative Examples 1 to 3. This indicates that the overall efficiency of the electroluminescent devices prepared by using the compounds of the present invention as the guest luminescent materials is improved.

[0154] Comparing Examples 5 to 10 with Examples 2 to 4, it can be seen that the color coordinates of the electroluminescent devices of Examples 5 to 10 are significantly blue-shifted compared to those of the electroluminescent devices of Examples 2 to 4, and the external quantum efficiency is also slightly improved. This is because the M series intermediates of the corresponding compounds (Compound 99, Compound 100, Compound 101, Compound 298, Compound 299, Compound 300) of Examples 5 to 10 all contain electron-withdrawing groups, and the M series intermediates of the corresponding compounds (Compound 56, Compound 58, Compound 59) of Examples 2 to 4 all contain electron-donating groups, indicating that the electron-donating substituents (such as isopropylamino, dimethyl, dimethylsilyl) increase the electron cloud density around the competing ligand (metal Pt element), because the competing ligand (metal Pt element) itself is positively charged, and its electron-withdrawing properties cause the highest occupied molecular orbital (HOMO) level of the compound to be unstable, thereby producing a wavelength red shift phenomenon.

[0155] In summary, it can be seen that the spirofluorene metal platinum complex containing N heteroatom of the present invention is used as the guest luminescent material in the luminescent layer in the electroluminescent device, and compared with the comparative example, an electroluminescent device with bluer emission light, lower starting voltage, better luminous efficiency and life is obtained. It shows that the spirofluorene metal platinum complex containing N heteroatom of the present invention has certain application value.

[0156] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge scope of ordinary technicians in this field without departing from the purpose of the present invention.

Claims

1. A spirofluorene metal platinum complex containing a N heteroatom, characterized in that: The structure of the spirofluorene metal platinum complex containing N heteroatom is shown in formula (1): In the formula: Z1 and Z2 are independently C atoms or N atoms, and Z1 and Z2 are not N atoms at the same time; A is selected from one of the following groups Y1 to Y13: " " indicates the bonding position between A and the Pt atom in the main structure, and " ” indicates the bonding position of A to the benzene ring in the main structure; B is selected from one of the following groups R1 to R17: " " is the bonding position between B and the main structure, and R in the group R17 is selected from phenyl, m-methylphenyl and p-methylphenyl.

2. The spirofluorene metal platinum complex containing N heteroatom according to claim 1, characterized in that: The spirofluorene metal platinum complex containing a N heteroatom is selected from one of the following compounds 1 to 316: 。 3. An electroluminescent device, characterized in that: It comprises a cathode, an anode and an organic layer located between the cathode and the anode, wherein the organic layer comprises a hole transport layer, a light-emitting layer and an electron transport layer, wherein the hole transport layer is located between the anode and the light-emitting layer, and the electron transport layer is located between the cathode and the light-emitting layer; the components of the light-emitting layer comprise a host light-emitting material and a guest light-emitting material, wherein the guest light-emitting material comprises the spirofluorene metal platinum complex containing a N heteroatom according to any one of claims 1 to 2.

4. The electroluminescent device according to claim 3, characterized in that The mass of the guest luminescent material accounts for 0.5% to 3% of the mass of the luminescent layer.

5. The electroluminescent device according to claim 3, characterized in that: The host luminescent material comprises a first host material and a second host material; The first host material is selected from any one of the following RH1-1 to RH1-4: The second main material is selected from any one of the following RH2-1 to RH2-4: 。 6. The electroluminescent device according to claim 5, characterized in that The mass ratio of the first host material to the second host material is (40~60):(40~60).

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