Green phosphorescent divalent platinum complexes, their preparation methods and applications, and organic optoelectronic devices

Abstract

This invention relates to the field of optoelectronic materials technology, and discloses a green phosphorescent divalent platinum complex, its preparation method and application, as well as an organic optoelectronic device. The green phosphorescent platinum complex has the structure shown in formula (I): R a R b R c R d and R f Each can be independently monosubstituted or disubstituted, R e It is a single substituent, and R e Selected from alkyl, aryl-substituted alkyl, fluorine-substituted alkyl, aryl, or alkyl-substituted aryl; this green phosphorescent divalent platinum complex can effectively improve the color purity of native green light, thereby effectively increasing the proportion of green light emission in OLED panel manufacturing materials, and ultimately improving the luminous efficiency and reducing actual energy consumption in practical applications.

Description

Technical Field

[0001] This invention relates to the field of optoelectronic materials technology, specifically to a green phosphorescent divalent platinum complex, its preparation method and application, and organic optoelectronic devices. Background Technology

[0002] Compounds capable of absorption and / or emission are suitable for various optical and optoelectronic devices, including but not limited to light-absorbing devices such as solar cells and photosensitive devices, organic light-emitting diodes (OLEDs), light-emitting devices, or devices with both light absorption and emission capabilities, as well as related applications for biomarking. Much research has been conducted in this field specifically to discover organic and organometallic materials for optical and electroluminescent devices. Significant progress has been made in the research of optoelectronic materials applicable to light-emitting and lighting devices (red and green organometallic materials used as phosphorescent materials, and blue organometallic materials used as fluorescent materials), and these have been successfully applied in OLED lighting and advanced displays. Currently, the green phosphorescent materials used in OLED displays are mostly iridium complex systems. Due to the limitations of precious metal reserves and production, and price fluctuations, the large-scale use of iridium complex materials will lead to the depletion of iridium resources and an unlimited increase in price. Therefore, it is necessary to develop organic light-emitting materials other than iridium complex systems, including other types of metal complex materials. Furthermore, the ultra-high-definition display industry is constantly increasing its demands on the color gamut of the three primary colors, requiring the development of new, high-efficiency organic light-emitting materials with a wide color gamut, namely, a new generation of organic light-emitting materials based on the three primary colors, in order to better ensure that the intrinsic emission spectrum of the materials conforms to the International Telecommunication Union (ITU) 2020 color standard.

[0003] According to the International Commission on Illumination (CIE) chromaticity coordinates, monochromatic light with wavelengths between 510 and 540 nm is the most saturated green light. However, excellent organic light-emitting materials are currently scarce, especially high-efficiency phosphorescent materials that simultaneously possess a stable structure and a suitable emission spectrum.

[0004] Therefore, the development of green phosphorescent materials is the main demand direction for the current development of organic displays. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing OLED devices, which lack complex luminescent materials capable of emitting stable and efficient green light. This invention provides a green phosphorescent divalent platinum complex, its preparation method and application, as well as an organic optoelectronic device. This green phosphorescent divalent platinum complex can effectively improve the color purity of native green light, thereby effectively increasing the proportion of green light emission in the material application of OLED panel preparation, and ultimately improving the luminous efficiency and reducing the actual energy consumption in practical applications.

[0006] To achieve the above objectives, a first aspect of the present invention provides a green phosphorescent divalent platinum complex, wherein the green phosphorescent platinum complex has the structure shown in formula (I):

[0007]

[0008] In equation (I):

[0009] R a R b R c R d and R f Each can be independently monosubstituted or disubstituted, and R a R b R c R d and R f Each is independently selected from monatomic or polyatomic substituents; the monatomic substituent includes a hydrogen atom, an isotope of hydrogen, or a halogen atom; the polyatomic substituent includes alkyl, aryl-substituted alkyl, fluorine-substituted alkyl, aryl, alkyl-substituted aryl, aryl-substituted aryl, cycloalkyl, cycloalkenyl, heteroaryl, alkenyl, alkoxy, aryloxy, haloalkyl, silyl, or the above substituents containing isotope atoms;

[0010] R e It is a single substituent, and R e It is selected from alkyl, aryl-substituted alkyl, fluorine-substituted alkyl, aryl, or alkyl-substituted aryl.

[0011] A second aspect of the present invention provides a method for preparing the aforementioned green phosphorescent divalent platinum complex, wherein the method comprises:

[0012] (1) Under a protective gas, compound a shown in formula (a) and compound b of formula (b) are subjected to a first coupling reaction to obtain compound c shown in formula (c);

[0013] (2) Under a protective gas, compound c shown in formula (c) is reduced to obtain compound d shown in formula (d);

[0014] (3) Under a protective gas, compound d as shown in formula (d) is coupled with ortho-halogenated aniline with substituents in a second coupling reaction to obtain compound e as shown in formula (e);

[0015] (4) Under a protective gas, compound e, as shown in formula (e), is reacted with ammonium hexafluorophosphonate to obtain compound f, as shown in formula (f);

[0016] (5) Compound f, as shown in formula (f), is subjected to a cyclometalation reaction to obtain the divalent platinum complex shown in formula (I);

[0017]

[0018]

[0019] The definitions of the groups in formulas (I), (a), (b), (c), (d), (e), and (f) are the same as those described above.

[0020] A third aspect of the present invention provides an application of the aforementioned green phosphorescent divalent platinum complex in organic optoelectronic devices.

[0021] A fourth aspect of the present invention provides an organic optoelectronic device comprising a substrate, an anode layer, a hole transport layer, a light-emitting layer, an electron transport layer, and a metal cathode layer, wherein at least one of the light-emitting layer, the electron transport layer, and the hole transport layer comprises the aforementioned green phosphorescent divalent platinum complex.

[0022] The green phosphorescent divalent platinum complex provided by this invention is a carbene-coordinated green phosphorescent material. This green phosphorescent material is used as a dopant in OLED light-emitting devices and equipment, emitting green light with a peak value between 510-540 nm. Such complexes exhibit excellent spectral luminescence properties in photoluminescent and electroluminescent devices, which is beneficial for promoting the development of green phosphorescent materials and improving the performance of light-emitting devices. Attached Figure Description

[0023] Figure 1 This is the emission spectrum of the green phosphorescent divalent platinum complex 1 prepared according to Example 1 of the present invention in solution and thin film;

[0024] Figure 2 This is the UV-Vis absorption spectrum of the green phosphorescent divalent platinum complex 1 prepared according to Example 1 of the present invention in solution and thin film;

[0025] Figure 3 This is the green phosphorescent divalent platinum complex 1 prepared according to Example 1 of the present invention. 1 H NMR spectrum;

[0026] Figure 4 This is the mass spectrum of the green phosphorescent divalent platinum complex 1 prepared according to Example 1;

[0027] Figure 5 This is a cross-sectional view of an OLED device according to an embodiment of the present invention;

[0028] Figure 6 This is a structural diagram of a device prepared using the green phosphorescent divalent platinum complex 1 prepared in Example 1 of this invention;

[0029] Figure 7 This is the emission spectrum of the device using the green phosphorescent divalent platinum complex 1 prepared in Example 1 of the present invention;

[0030] Figure 8 The images show the current density-voltage diagram (a) and brightness-voltage diagram (b) of an OLED device prepared by doping with the green phosphorescent divalent platinum complex 1 prepared in Example 1 of this invention.

[0031] Figure 9 The diagram shows the luminous current efficiency (a) and power efficiency (b) of the OLED device using the green phosphorescent divalent platinum complex 1 prepared in Example 1 of this invention.

[0032] Explanation of reference numerals in the attached figures

[0033] 1000 Organic optoelectronic device 1002 Substrate 1004 Anode layer

[0034] 1006 Hole transport layer 1008 Emissive layer 1010 Electron transport layer

[0035] 1012 metal cathode layer Detailed Implementation

[0036] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0037] As previously stated, the first aspect of the present invention provides a green phosphorescent divalent platinum complex, wherein the green phosphorescent platinum complex has the structure shown in formula (I):

[0038]

[0039] In equation (I):

[0040] R a R b R c R d and R f Each can be independently monosubstituted or disubstituted, and R a R b R c R d and R fEach is independently selected from monatomic or polyatomic substituents; the monatomic substituent includes a hydrogen atom, an isotope of hydrogen, or a halogen atom; the polyatomic substituent includes alkyl, aryl-substituted alkyl, fluorine-substituted alkyl, aryl, alkyl-substituted aryl, aryl-substituted aryl, cycloalkyl, cycloalkenyl, heteroaryl, alkenyl, alkoxy, aryloxy, haloalkyl, silyl, or the above substituents containing isotope atoms;

[0041] R e It is a single substituent, and R e It is selected from alkyl, aryl-substituted alkyl, fluorine-substituted alkyl, aryl, or alkyl-substituted aryl.

[0042] The inventors of this invention have discovered that by introducing benzimidazole-type carbene into the ligands of divalent platinum complexes, a new and stable green phosphorescent material, namely a green phosphorescent divalent platinum complex, is provided, suitable as an organic green phosphorescent emitter in OLED-related products. When applied to OLED devices, this green emitter effectively improves the color purity of native green light, thereby increasing the effective green light emission ratio in OLED panel fabrication materials, ultimately improving luminous efficiency and reducing actual energy consumption. Furthermore, the green phosphorescent divalent platinum complex provided by the embodiments of this invention is easy to prepare and sublimate for purification, soluble in common organic solvents, and suitable for both vapor deposition and solution processing methods. This type of material exhibits low energy and high color purity, changing the situation of a lack of stable and efficient green doping materials in the flat panel display field, while simultaneously achieving the effect of emitting green light and improving device performance. The CIE coordinates of the intrinsic emission spectrum of this stable green phosphorescent divalent platinum complex provided by the embodiments of this invention are more in line with the requirements of flat panel displays.

[0043] Optionally, R a R b R c R d and R f Each atom is independently selected from deuterium atoms.

[0044] Optionally, R in the divalent platinum complex a R b R c R d R e and R fEach of the following is independently selected from methyl, benzyl, diphenylmethyl, triphenylmethyl, ethyl, 2-phenylethyl, 2,2-phenylethyl, 2,2,2-trifluoroethyl, propyl, isopropyl, 3,3,3-trifluoropropyl, 1,1,1,3,3,3-hexafluoro-2-propyl, butyl, isobutyl, hexafluoroisobutyl, tert-butyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, phenyl, 2-methylphenyl, 2-isopropylphenyl, 2-ethylphenyl, 4-methylphenyl 4-Isopropylphenyl, 4-Ethylphenyl, 4-tert-butylphenyl, 2,3-Dimethylphenyl, 2,3-Diethylphenyl, 2,3-Diisopropylphenyl, 2,3-Diisobutylphenyl, 2,3-Dicyclohexylphenyl, 2,3-Dicyclopropylphenyl, 2,3-Dicyclobutylphenyl, 2,3-Dicyclopentylphenyl, 2,4-Dimethylphenyl, 2,4-Diethylphenyl, 2,4-Diisopropylphenyl, 2,4-Diisobutylphenyl, 2,4-Dicyclohexylphenyl 2,4-Dicyclopropylphenyl, 2,4-Dicyclobutylphenyl, 2,4-Dicyclopentylphenyl, 2,6-Dimethylphenyl, 2,6-Diethylphenyl, 2,6-Diisopropylphenyl, 2,6-Diisobutylphenyl, 2,6-Dicyclohexylphenyl, 2,6-Dicyclopropylphenyl, 2,6-Dicyclobutylphenyl, 2,6-Dicyclopentylphenyl, 3,5-Dimethylphenyl, 3,5-Diethylphenyl, 3,5-Diisopropylphenyl, 3,5-Diisobutylphenyl 2,3,5-dicyclohexylphenyl, 3,5-dicyclopropylphenyl, 3,5-dicyclobutylphenyl, 3,5-dicyclopentylphenyl, 2,3,5,6-tetramethylphenyl, 2,4,6-trimethylphenyl, 2,4,6-triethylphenyl, 2,4,6-triisopropylphenyl, 2,4,6-triisobutylphenyl, 2,4,6-tricyclohexylphenyl, 2,4,6-tricyclopropylphenyl, 2,4,6-tricyclobutylphenyl or 2,4,6-tricyclopentylphenyl.

[0045] Optionally, R in the divalent platinum complex a R b R c R d R e and R f Each is independently selected from deuterated substituents -CDH2, -CD2H, -CD3, -CDR1R2 or -CD2R1, wherein R1 and R2 are substituents, and each of R1 and R2 is independently selected from alkyl, aryl-substituted alkyl, aryl, alkyl-substituted aryl, aryl-substituted aryl, cycloalkyl, cycloalkenyl, heteroaryl, alkenyl, alkoxy, aryloxy, haloalkyl or silyl.

[0046] In this invention, it should be noted that, for example, in the "-CDH2" group, "C" refers to carbon, "D" refers to deuterium (D), an isotope of hydrogen, also called heavy hydrogen, and so on.

[0047] Optionally, R in the divalent platinum complex a R b R c R d R e and R f Each is independently selected from deuterated aryl or substituted deuterated aryl-Ar-dn, wherein each Ar is independently selected from aryl, aryl-substituted aryl and alkyl-substituted aryl; the deuterated hydrogen dn is selected from one deuterated, multiple deuterated, or all hydrogens are deuterated.

[0048] According to the present invention, preferably, the divalent platinum complex has the structures shown in formulas (II) to (IV):

[0049]

[0050] In equation (I), when R e When an isopropyl group is selected as a substituent on the imidazole nitrogen atom, the divalent platinum complex has the structure shown in formula (II).

[0051] In equation (I), when R a When the 4-position of pyridine is a tert-butyl substituent, the divalent platinum complex has the structure shown in formula (III).

[0052] In equation (I), when R f When the 6-position substituent on the benzimidazole ring is isopropyl, the divalent platinum complex has the structure shown in formula (IV).

[0053] According to the present invention, preferably, the divalent platinum complex has the structure shown in complexes 1 to 30:

[0054]

[0055]

[0056]

[0057] A second aspect of the present invention provides a method for preparing the aforementioned green phosphorescent divalent platinum complex, wherein the method comprises:

[0058] (1) Under a protective gas, compound a shown in formula (a) and compound b of formula (b) are subjected to a first coupling reaction to obtain compound c shown in formula (c);

[0059] (2) Under a protective gas, compound c shown in formula (c) is reduced to obtain compound d shown in formula (d);

[0060] (3) Under a protective gas, compound d as shown in formula (d) is coupled with ortho-halogenated aniline with substituents in a second coupling reaction to obtain compound e as shown in formula (e);

[0061] (4) Under a protective gas, compound e, as shown in formula (e), is reacted with ammonium hexafluorophosphonate to obtain compound f, as shown in formula (f);

[0062] (5) Compound f, as shown in formula (f), is subjected to a cyclometalation reaction to obtain the divalent platinum complex shown in formula (I);

[0063]

[0064]

[0065] The definitions of the groups in formulas (I), (a), (b), (c), (d), (e), and (f) are the same as those described above.

[0066] According to the present invention, the schematic diagram of the synthesis process of the green phosphorescent divalent platinum complex is as follows:

[0067]

[0068] According to the present invention, in step (1), under a protective gas, compound a of formula (a) and compound b of formula (b) are introduced into a sealed tube, in addition to a catalyst, ligand, base and solvent, to carry out a first coupling reaction to obtain compound c of formula (c).

[0069] In this invention, all protective gases are nitrogen (N2).

[0070] In this invention, the catalyst is a copper catalyst or a palladium catalyst; the copper catalyst is selected from one or more of cuprous iodide, cuprous bromide and cuprous chloride, and the palladium catalyst is selected from one or more of tris(dibenzylacetone)palladium, tetratriphenylphosphine palladium and palladium acetate.

[0071] In this invention, the ligand is selected from one or more phosphine ligands such as 2-(di-tert-butylphosphine)biphenyl, 2-dicyclohexylphosphine-2',4',6'-triisopropylbiphenyl, 2-dicyclohexylphosphine-2′,6′-dimethoxy-biphenyl, and 1,1'-binaphthyl-2,2'-bisdiphenylphosphine, or selected from N 1 N 2 -Dimethylethane-1,2-diamine, 2,2,6,6-tetramethylheptanedione, N 1 N 2 One or more of bis(5-methyl-[1,1'-biphenyl]-2-yl)oxalamide, trans-cyclohexanediamine, 1-methylimidazole and L-Proline.

[0072] In this invention, the alkali is selected from one or more inorganic alkalis such as cesium carbonate, potassium carbonate, potassium phosphate, cesium fluoride, and potassium hydroxide, or from one or more organic alkalis such as sodium tert-butoxide, potassium tert-butoxide, and lithium tert-butoxide.

[0073] In this invention, the solvent is selected from one or more of dimethyl sulfoxide, N,N-dimethylformamide, 1,4-dioxane, ethylene glycol dimethyl ether, deionized water, and toluene.

[0074] In this invention, the molar ratio of compound a (a) shown in formula (b), compound b (b) of formula, catalyst, ligand and base is 1:(1.2-3):(0.02-0.2):(0.2-1):(1.2-3), preferably 1:1.2:0.02:0.2:1.2.

[0075] In this invention, the conditions for the first coupling reaction include: a temperature of 110-130°C and a time of 11-13 hours; preferably, the temperature is 120°C and the time is 12 hours.

[0076] According to the present invention, in step (2), under the protective gas N2, compound c shown in formula (c) is introduced into a sealed tube. It is usually reduced by palladium / carbon, but can also be reduced by other reducing agents such as iron powder. The solvent is a proton solvent such as methanol, ethanol, tetrahydrofuran, etc., to carry out the reduction reaction and obtain compound d shown in formula (d).

[0077] In this invention, the molar ratio of compound c shown in formula (c) to reducing agent is 1:(0.05-0.2), preferably 1:0.05.

[0078] In this invention, the conditions for the reduction reaction include: a temperature of room temperature and a time of 23-25 ​​hours, preferably a temperature of 15-35°C and a time of 24 hours.

[0079] According to the present invention, in step (3), compound d of formula (d) and various substituent ortho-halogen aniline are added to a sealed tube, in addition to a catalyst, ligand, base and solvent, to carry out a second coupling reaction to obtain compound e of formula (e).

[0080] In this invention, the reaction can be carried out using either a copper catalyst or a palladium catalyst. The reaction may require one or more copper catalysts such as cuprous iodide, cuprous bromide and cuprous chloride, or one or more palladium catalysts such as tris(dibenzylacetone)palladium, tetratriphenylphosphine palladium and palladium acetate.

[0081] In this invention, the ligand is selected from one or more of phosphine ligands such as 2-(di-tert-butylphosphine)biphenyl, 2-dicyclohexylphosphine-2',4',6'-triisopropylbiphenyl, 2-dicyclohexylphosphine-2′,6′-dimethoxy-biphenyl and 1,1'-binaphthyl-2,2'-bisdiphenylphosphine, or from one or more of N1,N2-dimethylethane-1,2-diamine, 2,2,6,6-tetramethylheptanedione, N1,N2-bis(5-methyl-[1,1'-biphenyl]-2-yl)oxalamide, transcyclohexanediamine, 1-methylimidazole and L-Proline.

[0082] In this invention, the alkali is selected from one or more inorganic alkalis such as cesium carbonate, potassium carbonate, potassium phosphate, cesium fluoride, and potassium hydroxide, or from one or more organic alkalis such as sodium tert-butoxide, potassium tert-butoxide, and lithium tert-butoxide.

[0083] In this invention, the solvent is selected from one or more of dimethyl sulfoxide, N,N-dimethylformamide, 1,4-dioxane, ethylene glycol dimethyl ether, deionized water, and toluene.

[0084] In this invention, the molar ratio of compound d (d) shown in formula (d), ortho-halogen aniline, catalyst, ligand and base is 1:(2-10):(0.1-2):(0.5-5):(2-8), preferably 1:2.0:0.1:0.5:2.

[0085] In this invention, the conditions for the second coupling reaction include: a temperature of 110-130°C and a time of 22-25 h, preferably a temperature of 120°C and a time of 24 h.

[0086] According to the present invention, in step (4), in addition to adding compound e of formula (e) and ammonium hexafluorophosphonate into the sealed tube, only triethyl orthoformate is added as a solvent to carry out the ring-closure reaction to obtain compound f of formula (f).

[0087] In this invention, the molar ratio of compound e (represented by formula (e)), ammonium hexafluorophosphonate and triethyl orthoformate is 1:(1.2-3):(0.25-2), preferably 1:1.2:0.25.

[0088] In this invention, the conditions for the ring-closing reaction include: a temperature of 110-130°C and a time of 23-25 ​​h, preferably a temperature of 120°C and a time of 24 h.

[0089] According to the present invention, in step (5), compound f of formula (f) is subjected to a cyclometalation reaction to obtain the divalent platinum complex of formula (I).

[0090] In this invention, the cyclometalation reaction step includes: mixing compound f shown in formula (f), cyclooctadienyl diplatinum(II) chloride and tetrahydrofuran evenly, wherein the molar ratio of compound f shown in formula (f) and cyclooctadienyl diplatinum(II) chloride is 1:(1.1-5), preferably 1:1.1; the concentration of tetrahydrofuran is preferably 0.01 mmol / ml.

[0091] In this invention, the conditions for the ring metallization reaction include: heating to 120-140°C and stirring for 71-73 hours in a nitrogen atmosphere, preferably, heating to 130°C and stirring for 72 hours in the presence of a protective gas, for example, in a nitrogen atmosphere.

[0092] A third aspect of the present invention provides an application of the aforementioned green phosphorescent divalent platinum complex in organic optoelectronic devices.

[0093] In this invention, the green light wavelength peak of the green phosphorescent divalent platinum complex provided by the embodiments of this invention is in the range of 510-540 nm.

[0094] A fourth aspect of the present invention provides an organic optoelectronic device comprising a substrate, an anode layer, a hole transport layer, a light-emitting layer, an electron transport layer, and a metal cathode layer, wherein at least one of the light-emitting layer, the electron transport layer, and the hole transport layer comprises the aforementioned green phosphorescent divalent platinum complex.

[0095] According to the present invention, the light-emitting layer contains a blue phosphorescent divalent platinum complex.

[0096] According to the present invention, the green phosphorescent divalent platinum complex is the luminescent material, host material, or guest material in the luminescent layer.

[0097] Figure 5 A cross-sectional view of an OLED light-emitting device 1000 is shown, which can use the divalent platinum complex described herein as the light-emitting material. The OLED device 1000 includes a substrate 1002, an anode layer 1004, a hole transport layer 1006, a light-emitting layer 1008, an electron transport layer 1010, and a metal cathode layer 1012. The anode 1004 is generally a transparent material, such as indium tin oxide. The light-emitting layer 1008 can be a light-emitting material comprising an emitter and a substrate. Here, EIL refers to the electron injection layer and can be considered as part of the electron transport layer 1010. HIL is the hole injection layer and can be considered as part of the hole transport layer 1006. CPL is the cathode capping layer. The divalent platinum complex described in this invention is used as a blue light-emitting dopant in the 1008 light-emitting layer.

[0098] The emitting layer 1008 may contain one or more divalent platinum complexes as described in this invention, and may optionally be associated with a host material. The ETL layer 1010 and HTL 1006 may also contain one or more divalent platinum complexes and another injection layer adjacent to the electrode. The material of the injection layer may include EIL (electron injection layer), HIL (hole injection layer), and CPL (cathode capping layer), and may be a single layer or dispersed in an electron or hole transport material. The host material may be any suitable host material known in the art. The emission color of the OLED is determined by the emission energy (optical bandgap) of the emitting layer 1008 material, and the emission energy (optical bandgap) of the emitting layer 1008 material can be tuned as described above by tuning the electronic structure of the emitting platinum complexes and / or the host material. The hole transport material in the HTL layer 1006 and the electron transport material in the ETL layer 1010 may include any suitable hole transporter known in the art.

[0099] The present invention will be described in detail below through embodiments.

[0100] Recorded in CDCl3 or DMSO-d6 solution using a liquid NMR spectrometer 1 HNMR (hydrogen nuclear magnetic resonance) and 13 C10 NMR (carbon nuclear magnetic resonance) spectra were recorded at 300, 400, or 500 MHz, with chemical shifts based on residual protonated solvent. If CDCl3 was used as the solvent, tetramethylsilane (δ = 0.00 ppm) was used as an internal reference for recording. 1 1H NMR (hydrogen nuclear magnetic resonance) spectroscopy; CDCl3 (δ = 77.00 ppm) was used as an internal reference for recording. 13 C10 NMR (carbon nuclear magnetic resonance) spectroscopy. If DMSO-d6 is used as the solvent, residual H2O (δ = 3.33 ppm) is used as an internal reference for recording. 1 1H NMR (hydrogen nuclear magnetic resonance) spectroscopy; DMSO-d6 (δ = 39.52 ppm) was used as an internal reference for recording. 13 C10 NMR (carbon nuclear magnetic resonance) spectroscopy. The following abbreviations are used for explanation. 1 Diversity of H NMR (hydrogen nuclear magnetic resonance): s = singlet state, d = doublet state, t = triplet state, q = tetrat state, p = pentatonic state, m = multitonic state, br = broad.

[0101] Material purification: The final product, a platinum complex, was separated by column chromatography and preparative HPLC, and then purified under ultra-high vacuum (10... -4 Pa to 10 -5 Pa) Sublimation purification equipment is used to sublimate and purify the material to the purity required for device fabrication.

[0102] High performance liquid chromatography analysis: The purity of platinum complex samples was analyzed using methanol / water (10% / 90%) as the mobile phase.

[0103] UV-Vis absorption spectroscopy: The absorption spectra of the platinum complex in dichloromethane solution at room temperature were measured, with a scanning range of 250-500 nm and an interval of 1 nm.

[0104] Steady-state spectroscopy tests were performed on the room-temperature dichloromethane solution spectrum of the platinum complex, the luminescence / excitation spectrum at 77 K 2-methyltetrahydrofuran, and the spectrum of the 5 wt% doped polymethyl methacrylate (PMMA) film. The dichloromethane solution spectrum was tested after thoroughly purging the solvent with nitrogen. The polymer-doped film was prepared by spin-coating in a glove box using chloroform as the solvent and a quartz sheet as the film carrier. Film samples were tested in a glove box or vacuum chamber to reduce the quenching effect of oxygen on the luminescence of the complex. Additionally, the photoluminescence quantum yield (PLQY) of the platinum complex solution and film was measured using an integrating sphere.

[0105] Transient spectroscopy and phosphorescence lifetime testing: Time-resolved spectroscopy and luminescence lifetime half-life testing of room temperature dichloromethane solutions of platinum complexes were performed using the Fluorolog-3 full-spectrum optical platform. Lifetime testing was also conducted on 5 wt% doped PMMA films. All tests were performed under nitrogen or vacuum conditions.

[0106] Example 1

[0107] This embodiment illustrates the preparation of complex 1.

[0108] Synthesis of 2-nitro-9-(3-(pyridin-2-yl)phenyl)-9H-carbazole:

[0109]

[0110] 2-Nitrocarbazole (15 mmol), 2-bromopyridine (18 mmol), cuprous iodide (0.3 mmol), L-proline (0.3 mmol), potassium carbonate (18 mmol), and dimethyl sulfoxide (50 mL) were added sequentially to a 48 mL sealed tube equipped with a magnetic rotor. The resulting mixture was bubbled under nitrogen for 10 minutes and then heated to 120 °C with stirring for 8 hours. After cooling to room temperature, the reaction was quenched with water, extracted with ethyl acetate, and the combined organic phases were washed with an appropriate amount of saturated sodium chloride aqueous solution and dried over anhydrous sodium sulfate. The solvent was removed by vacuum distillation, and the crude product was purified by silica gel column chromatography with petroleum ether:ethyl acetate = 25:1 as the eluent to give 2-nitro-9-(3-(pyridin-2-yl)phenyl)-9H-carbazole in 95% yield.

[0111] Synthesis of 9-(3-(pyridin-2-yl)phenyl)-9H-carbazole-2-amine:

[0112]

[0113] To a 100 mL round-bottom flask, add intermediate 2-nitro-9-(3-(pyridin-2-yl)phenyl)-9H-carbazole (10 mmol), palladium / carbon (0.5 mmol), and ethanol (50 mL). The resulting mixture is stirred at room temperature under hydrogen atmosphere for 24 hours. After the reaction is complete, filter and evaporate to dryness to give intermediate 9-(3-(pyridin-2-yl)phenyl)-9H-carbazole-2-amine (brown viscous liquid, 90% yield).

[0114] Synthesis of 2-bromo-N-isopropylaniline:

[0115]

[0116] Add 15 ml of acetone and 75 ml of acetic acid to a solution of 8 g of o-bromoaniline in 150 ml of dichloromethane. Add 6 ml of borane dimethyl sulfide solution at 0 °C, then stir overnight at room temperature. After the reaction is complete, adjust the pH to 8 with 25 wt% ammonia solution. Add 50 ml of water and extract three times with dichloromethane. Collect the organic phase and dry it with anhydrous sodium sulfate. Rotate the dryness to obtain the crude product of compound 2-bromo-N-isopropylaniline, which can be used directly in the next step (yellow oil, 95% yield).

[0117] N 1 -Isopropyl-N 2 Synthesis of -(9-(3-(pyridin-2-yl)phenyl)-9H-carbazole-2-yl)phenyl-1,2-diamine:

[0118]

[0119] Intermediate 2-bromo-N-isopropylaniline (5 mmol), intermediate 9-(3-(pyridin-2-yl)phenyl)-9H-carbazole-2-amine (5.5 mmol), tris(dibenzylacetone)palladium (0.25 mmol), 1,1'-binaphthyl-2,2'-bis(diphenylphosphine) (0.5 mmol), sodium tert-butoxide (7.5 mmol), and toluene (25 ml) were added to a sealed tube in a glove box. After bubbling the mixture for 15 minutes, it was heated at 130 °C for 20 hours. After cooling, ethyl acetate was added, and the mixture was filtered. The aqueous phase was extracted with ethyl acetate, and the organic phases were mixed, washed with brine, and dried over anhydrous Na₂SO₄. The obtained solution was purified by silica gel chromatography using petroleum ether:ethyl acetate = 6:1 as the eluent. The eluent was evaporated to dryness to give product N. 1 -Isopropyl-N 2 -(9-(3-(pyridin-2-yl)phenyl)-9H-carbazole-2-yl)phenyl-1,2-diamine (yellow viscous liquid, yield 85%).

[0120] Synthesis of carbene hexafluorophosphate:

[0121]

[0122] Add intermediate N to a sealing tube 1 -Isopropyl-N 2 1,2-Diamine (9-(3-(pyridin-2-yl)phenyl)-9H-carbazole-2-yl)phenyl-1,2-diamine (1 mmol), ammonium hexafluorophosphate (1.1 mmol), and triethyl orthoformate (2 mL) were added. The mixture was heated overnight at 120 °C. After cooling to room temperature, ethyl acetate was added to precipitate a yellow precipitate, which was filtered to give carbene hexafluorophosphate (brown solid, 50% yield).

[0123] Synthesis of Complex 1:

[0124]

[0125] Carbene hexafluorophosphate (0.5 mmol), cyclooctadienyl dichloroplatinum (0.55 mmol), and tetrahydrofuran (50 mL) were added to a sealed tube. The mixture was heated at 120 °C for 3 days. After cooling to room temperature, the solution was evaporated to dryness. The solution was purified by silica gel chromatography using dichloromethane:petroleum ether = 4:1 as the eluent to obtain the target product: complex 1 (bright yellow powder, yield 40%). 1 H NMR (500MHz, CDCl3) δ9.13(s,1H),8.43(d,J=8.3Hz,1H),8.31(d,J=8.3Hz,1H),8.00(d,J=8.0Hz,1H),7.88(d,J=9.9Hz,2H),7.77(d,J=22.8Hz, 2H),7.47–7.25(m,8H),7.06(dd,J=8.0,2.2Hz,1H),6.76(d,J=8.0Hz,1H),6.16–6.04(m,1H),1.61(dd,J=7.0,4.1Hz,6H).MS(ESI):672.2[M+H] + .

[0126] Figure 1 The emission spectra of the green phosphorescent divalent platinum complex 1 prepared in Example 1 of this invention in dichloromethane solution and PMMA film are shown. The peak emission wavelength of the film is 518 nm, which has a redshift effect compared to the emission wavelength of 517 nm in the solution. Both show better green light emission spectra, indicating that the green phosphorescent divalent platinum complex 1 is suitable for green light emission applications.

[0127] Figure 2 This is the UV-Vis absorption spectrum of the green phosphorescent divalent platinum complex 1 prepared in Example 1 of this invention in dichloromethane solution and PMMA film; from Figure 2It can be seen that the absorption spectrum intensity peak in the solution is significantly stronger than that in the thin film, indicating that the concentration of molecules in the thin film is too high, which may have caused an aggregation quenching effect.

[0128] Figure 3 This is the green phosphorescent divalent platinum complex 1 prepared in Example 1 of this invention. 1 The 1H NMR spectrum, through the proton spectrum, demonstrates that the green phosphorescent divalent platinum complex 1 can exist independently and stably, and can be separated, purified, and characterized.

[0129] Figure 4 The mass spectrum of the green phosphorescent divalent platinum complex 1 prepared according to Example 1 is shown. The molecular signal of the mass spectrometry shows that the M / C peak is 761.2, which is consistent with the molecular ion peak of the green phosphorescent divalent platinum complex 1, indicating that the structure of the green phosphorescent divalent platinum complex 1 is the designed structure.

[0130] Figure 6 This is a diagram showing the device structure prepared using the green phosphorescent divalent platinum complex 1 prepared in Example 1; complex 1 is used as a luminescent material and doped into the host material to prepare an OLED device. The OLED device structure can be... Figure 5 Adding charge blocking layers, such as hole blocking layers (HBLs) or electron blocking layers (EBLs), to the basic structure can improve device efficiency. The device structure is as follows: Figure 6 As shown: ITO / P-doping HT / HTL / EBL / Main material: Platinum complex / HBL / N-doping ET / Metal electrode. P-doping and N-doping refer to doping with P-type and N-type materials, respectively, which can be organic or inorganic materials. The platinum complex is the green light doping material of this invention. In addition, the complexes of the present invention can also be used in the following common device structures: ITO (150nm) / HATCN (10nm) / DBTPBDIA (50nm) / FSFA (60nm) / Host: Platinum complex (40nm) / NAPI:LiQ=1:1 (35nm) / Al (80nm); ITO / 4wt%ReO3:SimCP (60nm) / SimCP (15nm) / SimCP: Platinum complex (20nm) / PO-T2T (50nm) / Liq / Al; ITO / DNTPP / BPBPA / PCZAC / host: Platinum complex / DBFTrz / ZADN / LiF / Al; ITO / HATCN (10nm) / TAPC (10nm) / TCTA (8nm) / Host: Platinum complex (20nm) / TmPyPb (10nm) / Liq (2nm) / Al (120nm), etc. Figure 6The schematic diagram of the OLED structure containing EBL and HBL layers is shown in the present invention. By adding a barrier layer, the electron utilization rate and luminous efficiency can be improved, and the stability of the device can also be increased.

[0131] The compound names for device-doped functional materials are as follows:

[0132] HATCN is 1,4,5,8,9,12-hexaazabenzohexacarbonitrile;

[0133] DBTPBDIA is N,N′-diphenyl-N,N′-bis[(4′-diphenylamino)biphenyl-4-yl]benzidine;

[0134] FSFA is N-((1,1′-biphenyl)-2-yl)-N-(9,9-dimethyl-9H-fluorene-2-yl)-9,9′-spirocyclic[fluorene]-2-amino;

[0135] NAPI is 2-(4-(9,10-bis(naphthyl-2-yl)anthracene-2-yl)phenyl)-1-phenyl-1H-benzo[d]imidazolium;

[0136] SimCP is 3,5-bis(9-carbazolyl)tetraphenylsilane; PO-T2T is 1,3,5-triazine-(2,4,6-triyl)tris(phenyl-3,1-diyl)tris(diphenylphosphine oxide);

[0137] DNTPP is N,N′-diphenyl-N,N′-bis[4(phenyl-m-tolyl-amino)-phenyl]-biphenyl-4,4′-diamine;

[0138] BPBPA is N,N,N',N'-tetra[(1,10-biphenyl)-4-yl]-(1,10-biphenyl)-4,4'-diamine;

[0139] PCZAC is 9,9-dimethyl-10-(9-phenyl-9H-carbazol-3-yl)-9,10-dihydroacridine;

[0140] DBFTrz is 2,8-bis(4,6-diphenyl-1,3,5-triazin-2-yl)dibenzo[b,d]furan;

[0141] ZADN is 2-[4-(9,10-dinaphth-2-ylanthracene-2-yl)-phenyl]-1-phenyl-1H-benzimidazole;

[0142] TAPC is bis-[4-(N,N-diamino)-phenyl]cyclohexane;

[0143] TCTA is 4,4',4'-tris(N-carbazolyl)-triphenylamine;

[0144] TmPyPB is 1,3,5-tris(m-pyridin-3-ylphenyl)benzene; Liq is 8-hydroxyquinoline lithium.

[0145] Figure 7 The image shows the emission spectrum of a device using the green phosphorescent divalent platinum complex 1 prepared in Example 1 of this invention. The structure is ITO / HATCN (10nm) / TAPC (10nm) / TCTA (8nm) / mCBP:platinum complex (20nm) / TmPyPb (10nm) / Liq (2nm) / Al (120nm). The electroluminescence spectrum of the device with an 8% platinum complex doped in the luminescent layer shows that the emission peak is located at 523nm, a 5nm redshift relative to its photoluminescence peak in PMMA medium. The full width at half maximum (FWHM) is similar, maintaining the luminescent properties of the complex itself. The calculated chromaticity coordinates are CIE (0.30, 0.65), indicating that this device is suitable for use as a green light-emitting device.

[0146] The full Chinese names of the device compounds are as follows:

[0147] HATCN (Chinese name: 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazabenzophenanthrene material);

[0148] TCTA (Chinese name: 4,4′,4”-tris(carbazole-9-yl)triphenylamine);

[0149] TAPC (Chinese name: 4,4′-cyclohexylbis[N,N-di(4-methylphenyl)aniline]);

[0150] TmPyPb (Chinese name: 3,3'-[5'-[3-(3-pyridyl)phenyl][1,1':3',1”-terphenyl]-3,3”-diyl]dipyridine);

[0151] mCBP (Chinese name: 3,3'-bis(9H-carbazole-9-yl)-1,1'-biphenyl).

[0152] Figure 8 The images show the current density-voltage diagram (a) and brightness-voltage diagram (b) of an OLED device prepared by doping with the green phosphorescent divalent platinum complex 1 prepared in Example 1 of this invention. Figure 8 (a) The results of current density-voltage testing using a photoelectric testing system were obtained for an OLED device fabricated using coordination compound 1 as a green light doping material at room temperature. The test results show that the light-emitting device using the coordination compound of the present invention can perform charge transport very well.

[0153] Figure 8(b) The image shows the brightness-voltage test results of an OLED device prepared using coordination compound 1 as a green light doping material at room temperature, conducted using a photoelectric testing system. The test results indicate that the light-emitting device using the coordination compound of this invention has a low turn-on voltage, thereby reducing power consumption and improving device efficiency. As shown in the figure, the turn-on voltage of the green OLED device prepared using this invention is 2.9V.

[0154] Figure 9 The luminous current efficiency of the OLED device using the green phosphorescent divalent platinum complex 1 prepared in Example 1 of this invention is... Figure 9 (a) and power efficiency Figure 9 (b); Figure 9 (a) The current efficiency of the prepared light-emitting device was tested using a photoelectric testing system. The test results show that the light-emitting device using the platinum complex of this invention has high current efficiency. From Figure 9 (a) It can be seen that the current efficiency of the light-emitting device prepared by complex 1 is 1000 cd / m 2 It can reach 81.2 cd·A -1 The maximum current efficiency is 85.5 cd·A. -1 .

[0155] Figure 9 (b) The power efficiency of the prepared light-emitting device was tested using a photoelectric testing system. The test results show that the light-emitting device using the platinum complex of this invention has high power efficiency. From Figure 9 (b) It can be seen that the power efficiency of the light-emitting device prepared by complex 1 is 1000 cd / m². 2 It can reach 60.0 lm / W, with a maximum power efficiency of 94.3 lm / W.

[0156] Example 2

[0157] This embodiment illustrates the preparation of complex 2.

[0158] Synthesis of 9-(3-(4-(tert-butyl)pyridin-2-yl)phenyl)-2-nitro-9H-carbazole:

[0159]

[0160] To a 25 mL Shrek tube, add intermediates 2-(3-bromophenyl)-4-(tert-butyl)pyridine (10 mmol), 2-nitrocarbazole (12 mmol), cuprous iodide (1 mmol), L-proline (2 mmol), cesium carbonate (20 mmol), and dimethyl sulfoxide (20 mL). The resulting mixture was bubbled under nitrogen for 10 minutes and stirred at 120 °C for 3 days. After cooling, water and ethyl acetate were added, and the mixture was filtered. The aqueous phase was extracted with ethyl acetate, and the organic phases were combined, washed with brine, and dried over anhydrous sodium sulfate. The resulting solution was purified by silica gel chromatography using petroleum ether:ethyl acetate = 8:1 as the eluent to give the product 9-(3-(4-(tert-butyl)pyridin-2-yl)phenyl)-2-nitro-9H-carbazole (green solid, 70% yield).

[0161] Synthesis of 9-(3-(4-(tert-butyl)pyridin-2-yl)phenyl)-9H-carbazole-2-amine:

[0162]

[0163] To a 100 mL round-bottom flask, add intermediate 9-(3-(4-(tert-butyl)pyridin-2-yl)phenyl)-2-nitro-9H-carbazole (5 mmol), Pd / C (0.5 mmol), and ethanol (50 mL). The resulting mixture is stirred at room temperature under hydrogen atmosphere for 12 hours. After the reaction is complete, filter and evaporate to dryness to give intermediate 9-(3-(4-(tert-butyl)pyridin-2-yl)phenyl)-9H-carbazole-2-amine (brown viscous liquid, 90% yield).

[0164] N 1 -(9-(3-(4-(tert-butyl)pyridin-2-yl)phenyl)-9H-carbazole-2-yl)-N 2 - Isopropylphenyl-1,2-diamine Synthesis

[0165]

[0166] Intermediate 9-(3-(4-(tert-butyl)pyridin-2-yl)phenyl)-9H-carbazole-2-amine (2 mmol), 9-(3-(pyridin-2-yl)phenyl)-9H-carbazole-2-amine (2.2 mmol), tris(dibenzylacetone)palladium (0.1 mmol), 1,1'-binaphthyl-2,2'-bis(diphenylphosphine) (0.1 mmol), sodium tert-butoxide (3 mmol), and toluene (10 ml) were added to a sealed tube in a glove box. After bubbling the mixture for 15 minutes, it was heated at 130 °C for 20 hours. After cooling, ethyl acetate was added, and the mixture was filtered. The aqueous phase was extracted with ethyl acetate, and the organic phases were mixed, washed with brine, and dried over anhydrous sodium sulfate. The obtained solution was purified by silica gel chromatography using petroleum ether:ethyl acetate = 6:1 as the eluent. The eluent was evaporated to dryness to give product N. 1-(9-(3-(4-(tert-butyl)pyridin-2-yl)phenyl)-9H-carbazole-2-yl)-N 2 - Isopropylphenyl-1,2-diamine (yellow viscous liquid, yield 85%).

[0167] Synthesis of carbene hexafluorophosphate:

[0168]

[0169] Add intermediate N to a sealing tube 1 -(9-(3-(4-(tert-butyl)pyridin-2-yl)phenyl)-9H-carbazole-2-yl)-N 2 - Isopropylbenzene-1,2-diamine (1 mmol), ammonium hexafluorophosphate (1.1 mmol), and triethyl orthoformate (2 ml). Heat at 120 °C overnight. After cooling to room temperature, add ethyl acetate to precipitate a yellow precipitate, which is then filtered to give carbene hexafluorophosphate (brown solid, 50% yield).

[0170] Synthesis of Complex 2:

[0171]

[0172] Carbene hexafluorophosphate (0.5 mmol), dichloro(1,5-cyclooctadiene)platin(II) (0.55 mmol), sodium acetate (0.525 mmol), and tetrahydrofuran (50 mL) were added to a sealed tube. The mixture was heated at 120 °C for 3 days. After cooling to room temperature, the solution was evaporated to dryness and purified by silica gel chromatography using dichloromethane:petroleum ether = 4:1 as the eluent to give complex 2 (bright yellow powder, yield 39%). 1 H NMR (500MHz, CDCl3) δ10.68–10.63(s,1H),9.27–9.22(s,1H),8.70–8.62(d,J=7.2Hz,2H),8.53–8.38(d,J=8.2Hz,2H),8.31–8.07(m,6H) ,8.02–7.89(s,1H),7.88–7.69(m,5H),7.64–7.50(m,5H),2.41–2.32(s,1H),1.51–1.42(m,9H),1.16–1.01(m,6H).MS(ESI):728.3[M+H] + .

[0173] Example 3

[0174] This embodiment illustrates the preparation of complex 3.

[0175] Synthesis of 2-chloro-N,5-diisopropylaniline:

[0176]

[0177] Add 15 ml of acetone and 25 ml of acetic acid to a solution of 8.2 g of 2-chloro-5-isopropylaniline in 20 ml of dichloromethane. Add 6 ml of borane dimethyl sulfide solution at 0 °C, then stir overnight at room temperature. After the reaction is complete, adjust the pH to 8 with 25 wt% ammonia solution. Add 50 ml of water and extract three times with dichloromethane. Collect the organic phase and dry it with anhydrous sodium sulfate. The crude product of 2-chloro-N,5-diisopropylaniline (yellow oil) is used directly in the next step.

[0178] N 2,4 -Diisopropyl-N 1 Synthesis of 9-(3-(pyridin-2-yl)phenyl)-9H-carbazole-2-yl)phenyl-1,2-diamine

[0179]

[0180] Add 2-chloro-N,5-diisopropylaniline (1 mmol), 9-(3-(pyridin-2-yl)phenyl)-9H-carbazole-2-amine (1.1 mmol), tris(dibenzylacetone)palladium (0.05 mmol), 1,1'-binaphthyl-2,2'-bis(diphenylphosphine) (0.05 mmol), sodium tert-butoxide (0.15 mmol), and toluene (5 ml) to a sealed tube in a glove box. After bubbling the mixture for 15 minutes, heat the mixture at 130 °C for 20 hours. After cooling, add ethyl acetate and filter the mixture. Extract the aqueous phase with ethyl acetate, and mix the organic phases, wash with brine, and dry with anhydrous sodium sulfate. Use petroleum ether:ethyl acetate = 6:1 as the eluent, and purify the obtained solution by silica gel chromatography. Rotate the eluent to dryness to give product N. 2,4 -Diisopropyl-N 1 -(9-(3-(pyridin-2-yl)phenyl)-9H-carbazole-2-yl)phenyl-1,2-diamine (yellow viscous liquid, yield 85%).

[0181] Synthesis of carbene hexafluorophosphate:

[0182]

[0183] Add intermediate N to a sealing tube 2,4 -Diisopropyl-N 1 1,2-Diamine (9-(3-(pyridin-2-yl)phenyl)-9H-carbazole-2-yl)phenyl-1,2-diamine (1 mmol), ammonium hexafluorophosphate (1.1 mmol), and triethyl orthoformate (2 ml) were added. The mixture was heated overnight at 120 °C. After cooling to room temperature, ethyl acetate was added to precipitate a yellow precipitate, which was filtered to give carbene hexafluorophosphate (brown solid, 50% yield).

[0184] Synthesis of complex 3:

[0185]

[0186] Carbene hexafluorophosphate (0.5 mmol), dichloro(1,5-cyclooctadiene)platinum (0.55 mmol), sodium acetate (0.525 mmol), and tetrahydrofuran (50 mL) were added to a sealed tube. The mixture was heated at 120 °C for 3 days. After cooling to room temperature, the solution was evaporated to dryness. The solution was purified by silica gel chromatography using dichloromethane:petroleum ether = 4:1 as the eluent to give complex 3 (bright yellow powder, yield 30%). 1 H NMR (500MHz, CDCl3) δ10.33–10.19(s,1H),9.36–9.28(s,1H),8.78–8.69(d,J=8.1 Hz,2H),8.55–8.48(m,J=7.6Hz,1H),8.39–8.34(m,1H),8.34–8.24(d,J=8.3Hz,2H) ,8.21–8.16(m,1H),8.09–8.03(m,1H),7.90–7.75(m,4H),7.73–7.62(m,1H),7.60– 7.45(d,J=7.2Hz,2H),3.68–3.55(m,2H),1.82–1.69(m,12H).MS(ESI):714.3[M+H] + .

[0187] Test Example 1

[0188] Photophysical properties characterization of complexes 1, 2, and 3

[0189] Representative data on emitter color purity can be obtained from the emission spectra of thin films prepared using a 5% PMMA or dichloromethane solution.

[0190] Table 1 shows the emission spectra of the green phosphorescent divalent platinum complexes prepared in Examples 1-3. In Table 1, λ is the peak wavelength and FWHM is the full width at half maximum (FWHM).

[0191] Table 1

[0192]

[0193] a / b Measurement data in dichloromethane solution / PMMA.

[0194] The data above shows that the peak green light wavelength of the divalent platinum complexes provided in Examples 1-3 of the present invention is in the range of 510-530 nm. Under 340 nm ultraviolet light excitation, the emission wavelengths of the three complexes in dichloromethane solution are between 505-540 nm, and the emission wavelengths in PMMA are between 510-540 nm. This indicates that the green phosphorescent divalent platinum complexes prepared in Examples 1-3 of the present invention are excellent green luminescent materials.

[0195] Test Example 2

[0196] The performance of the light-emitting devices prepared from the green phosphorescent divalent platinum complexes 1, 2, and 3 prepared in Examples 1-3 is shown in Table 2.

[0197] Table 2

[0198]

[0199] The electroluminescence wavelength of a light-emitting device is primarily determined by the photoluminescence of the platinum complex itself, and the purity of the photoluminescence spectrum of the platinum complex is directly related to the spectral purity of its electroluminescence. Under the same conditions, the efficiency of the light-emitting device also follows the trend of the quantum efficiency of the platinum complex's own light emission, and the color purity of the emitted light is directly related to the spectral color purity of the emitted light under photoexcitation of the doped material itself. A comparison of the electroluminescence spectrum of the platinum complex light-emitting device and that of a thin-film photoluminescent device reveals a slight redshift, with most of the spectrum falling within the green light range. The calculated chromaticity coordinates indicate that this light-emitting device is a green light-emitting device. Since most of the light is in the green light region, only a small amount of long-wavelength light needs to be filtered out, indicating that the platinum compound material provided in the embodiments of this invention can fully meet the chromaticity requirements of high-efficiency pure green light devices in displays.

[0200] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A green phosphorescent divalent platinum complex, characterized in that, The green phosphorescent divalent platinum complexes have the structures shown in complexes 1 to 30:

2. A method for preparing the green phosphorescent divalent platinum complex according to claim 1, characterized in that, The preparation method includes: (1) Under a protective gas, compound a shown in formula (a) and compound b shown in formula (b) are subjected to a first coupling reaction to obtain compound c shown in formula (c); (2) Under a protective gas, compound c shown in formula (c) is reduced to obtain compound d shown in formula (d); (3) Under a protective gas, compound d as shown in formula (d) is coupled with ortho-halogenated aniline with substituents in a second coupling reaction to obtain compound e as shown in formula (e); (4) Under a protective gas, compound e, as shown in formula (e), is reacted with ammonium hexafluorophosphonate to obtain compound f, as shown in formula (f); (5) Compound f, as shown in formula (f), is subjected to a cyclometalation reaction to obtain the divalent platinum complex shown in formula (I); The definitions of the groups in formulas (I), (a), (b), (c), (d), (e), and (f) enable the prepared green phosphorescent platinum complexes to have the structures shown in complexes 1 to 30 of claims 1.

3. The method according to claim 2, wherein, In step (1), the first coupling reaction further includes being carried out in the presence of a catalyst, a ligand, a base, and a solvent; The catalyst is a copper catalyst or a palladium catalyst; the copper catalyst is selected from one or more of cuprous iodide, cuprous bromide and cuprous chloride, and the palladium catalyst is selected from one or more of tris(dibenzylacetone)palladium, tetratriphenylphosphine palladium and palladium acetate. The ligand is selected from phosphine ligands, N... 1 N 2 -Dimethylethane-1,2-diamine, 2,2,6,6-tetramethylheptanedione, N 1 N 2 One or more of bis(5-methyl-[1,1'-biphenyl]-2-yl)oxalamide, trans-cyclohexanediamine, 1-methylimidazolium and L-proline; The phosphine ligand is selected from one or more of 2-(di-tert-butylphosphine)biphenyl, 2-dicyclohexylphosphine-2',4',6'-triisopropylbiphenyl, 2-dicyclohexylphosphine-2',6'-dimethoxy-biphenyl and 1,1'-binaphthyl-2,2'-bisdiphenylphosphine; The base is an inorganic base or an organic base; wherein the inorganic base is selected from one or more of cesium carbonate, potassium carbonate, potassium phosphate, cesium fluoride and potassium hydroxide, and the organic base is selected from one or more of sodium tert-butoxide, potassium tert-butoxide and lithium tert-butoxide. The solvent is selected from one or more of dimethyl sulfoxide, N,N-dimethylformamide, 1,4-dioxane, ethylene glycol dimethyl ether, deionized water and toluene; The molar ratio of compound a (shown in formula (a)), compound b (shown in formula (b)), catalyst, ligand, and base is 1:(1.2-3):(0.02-0.2):(0.2-1):(1.2-3); The conditions for the first coupling reaction include: a temperature of 110-130℃ and a time of 11-13h.

4. The method according to claim 2, wherein, In step (2), the reduction reaction further includes being carried out in the presence of a solvent: The solvent is selected from one or more of methanol, ethanol, and tetrahydrofuran; In the reduction reaction, the reducing agent is either palladium / carbon reduction or iron powder reduction; The molar ratio of compound c shown in formula (c) to the reducing agent is 1:(0.05-0.2); The conditions for the reduction reaction include: room temperature and 23-25 ​​hours.

5. The method according to claim 2, wherein, In step (3), the second coupling reaction further includes being carried out in the presence of a catalyst, a ligand, a base, and a solvent; The catalyst is a copper catalyst or a palladium catalyst; The ligand is selected from phosphine ligands, N... 1 N 2 -Dimethylethane-1,2-diamine, 2,2,6,6-tetramethylheptanedione, N 1 N 2 One or more of bis(5-methyl-[1,1'-biphenyl]-2-yl)oxalamide, trans-cyclohexanediamine, 1-methylimidazolium and L-proline; The alkali is an inorganic alkali or an organic alkali; The solvent is selected from one or more of dimethyl sulfoxide, N,N-dimethylformamide, 1,4-dioxane, ethylene glycol dimethyl ether, deionized water and toluene; The molar ratio of compound d (shown in formula (d)), o-halogen aniline, catalyst, ligand, and base is 1:(2-10):(0.1-2):(0.5-5):(2-8); The conditions for the second coupling reaction include: a temperature of 110-130℃ and a time of 22-25h.

6. The method according to claim 2, wherein, In step (4), the cyclization reaction further includes being carried out in the presence of the solvent triethyl orthoformate; The molar ratio of compound e (represented by formula (e)), ammonium hexafluorophosphonate, and triethyl orthoformate is 1:(1.2-3):(0.25-2); The conditions for the ring-closing reaction include: a temperature of 110-130℃ and a time of 23-25h.

7. The method according to claim 2, wherein, In step (5), the cyclometalation reaction further includes: mixing compound f (shown in formula (f), cyclooctadienyl dichloride, and tetrahydrofuran) uniformly; The molar ratio of compound f shown in formula (f) to cyclooctadienyl platinum dichloride is 1:(1.1-5); The conditions for the ring metallization reaction include: heating to 120-140°C and stirring for 71-73 hours in a nitrogen atmosphere.

8. The application of the green phosphorescent divalent platinum complex according to claim 1 in organic optoelectronic devices.

9. An organic optoelectronic device, characterized in that, The device comprises a substrate, an anode layer, a hole transport layer, a light-emitting layer, an electron transport layer, and a metal cathode layer, wherein at least one of the light-emitting layer, the electron transport layer, and the hole transport layer contains the green phosphorescent divalent platinum complex as described in claim 1.

10. The organic optoelectronic device according to claim 9, wherein, The luminescent layer contains a blue phosphorescent divalent platinum complex.

11. The organic optoelectronic device according to claim 9 or 10, wherein, The green phosphorescent divalent platinum complex is the luminescent material, host material, or guest material in the luminescent layer.

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