Yellow-green phosphorescent platinum(ii) complexes, methods of making and using the same, and organic optoelectronic devices

Abstract

The application relates to the technical field of light-emitting materials, and discloses a yellow-green phosphorescent divalent platinum complex, a preparation method and application thereof, and an organic photoelectric device. The divalent platinum complex has a structure shown in formula (I), R a , b , c , d and R e are each independently present or not present, single or multiple substitutions, and R a , b , c , d and R e are each independently selected from monatomic or polyatomic substituents; the divalent platinum complex is a high-efficiency yellow-green phosphorescent light-emitting material and can be used as an organic light-emitting diode device.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of light-emitting materials, in particular to a yellow-green phosphorescent divalent platinum complex, a preparation method and application thereof, and an organic optoelectronic device. BACKGROUND

[0002] Organic light-emitting diodes (OLEDs) can emit different colors of light when powered on, and have good prospects in the display field. The products related to the molecular level semiconductor technology represented by OLED technology have many advantages in applicability, low energy consumption, etc. Based on the principle of three primary colors of light emission, OLEDs need to have red, green and blue three primary colors, or broad-spectrum white light, in order to realize white light illumination and full-color display applications. In addition, due to the higher requirements for light-emitting color and brightness of large-size panels, their color matching schemes are also more abundant. Since the human eye is most sensitive to yellow-green light around 555 nm, it is necessary to add a yellow-green phosphorescent material to the red, green and blue three primary color color matching scheme in the OLED panel to improve the brightness of the panel.

[0003] High-efficiency phosphorescent yellow-green light material molecules with stable structure and suitable light-emitting spectrum are relatively rare and have a great demand. SUMMARY

[0004] The purpose of the present application is to overcome the lack of complex luminescent materials capable of emitting stable and efficient phosphorescent yellow-green light in OLED devices in the prior art, and to provide a yellow-green phosphorescent divalent platinum complex, a preparation method and application thereof, and an organic optoelectronic device. The divalent platinum complex is a high-efficiency phosphorescent light-emitting material and can be used as an organic light-emitting diode device.

[0005] To achieve the above-mentioned purpose, the first aspect of the present application provides a yellow-green phosphorescent divalent platinum complex, wherein the divalent platinum complex has a structure shown in formula (I):

[0006]

[0007] In formula (I), R

[0008] R a , R b , R c , R d and R e each independently exist or not exist, and R a , R b , R c , R d and R e each independently selected from a single-atom or multi-atom substituent.

[0009] The single atom includes a hydrogen atom, an isotopic atom of hydrogen, or a halogen atom;

[0010] The polyatomic substituent includes an alkyl group, an aryl-substituted alkyl group, a fluorine-substituted alkyl group, an aryl group, an alkyl-substituted aryl group, an aryl-substituted aryl group, a cycloalkyl group, a cycloalkenyl group, a heteroaryl group, an alkenyl group, an alkynyl group, an amino group, a hydroxyl group, a mercapto group, a nitro group, a cyano group, an isocyano group, a sulfinyl group, a sulfonyl group, a carboxyl group, a hydrazine group, a mono-hydrocarbylamino group, a di-hydrocarbylamino group, a mono-arylamino group, a di-arylamino group, an alkoxy group, an aryloxy group, a halogenated alkyl group, an ester group, an alkoxycarbonyl group, an amido group, an alkoxycarbonylamino group, an aryloxycarbonylamino group, a sulfonamide group, a carbamoyl group, an alkylthio group, a urea group, a phosphoramide group, a silyl group, a polymer group, or the above-mentioned substituent containing an isotopic atom.

[0011] The second aspect of the present application provides a method for preparing the aforementioned yellow-green phosphorescent divalent platinum complex, wherein the method comprises:

[0012] (1) contacting a carbazolyl bipyridine represented by formula (II) and a bipyridine represented by formula (III) under a protective gas to perform a first coupling reaction, to obtain a compound represented by formula (IV) having a carbazolyl bipyridine;

[0013] (2) contacting the compound represented by formula (IV) having a carbazolyl bipyridine with a boronic acid or an amino substituent under a protective gas to perform a second coupling reaction, to obtain a compound represented by formula (V); and (3) performing a cyclometallation reaction on the compound represented by formula (V) in the presence of potassium chloroplatinite and acetic acid, to obtain the yellow-green phosphorescent divalent platinum complex represented by formula (I);

[0014]

[0015] In formula (III), X is Br, I, Cl, or OTf;

[0016] In formula (I), formula (II), formula (III), formula (IV), and formula (V), the definitions of the groups are the same as the aforementioned definitions.

[0017] The third aspect of the present application provides an application of the aforementioned yellow-green phosphorescent divalent platinum complex in an organic optoelectronic device.

[0018] The fourth aspect of the present application provides an organic optoelectronic device, wherein 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, and at least one of the light-emitting layer, the electron transport layer, and the hole transport layer comprises the aforementioned yellow-green phosphorescent divalent platinum complex.

[0019] The bivalent platinum complex provided by the technical scheme can be used as a yellow-green light device of an organic light emitting diode; under high concentration doping, the material can be used as a white light device. The material also has the characteristics of high thermal decomposition temperature, high quantum effect, etc., and is very stable in photoluminescence and device electroluminescence, and the application thereof can improve the application performance of current green phosphor devices. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is a luminescence spectrum diagram of complex 2 in solution and thin film according to an embodiment of the present application;

[0021] Figure 2 is an ultraviolet-visible absorption spectrum diagram of complex 2 in solution and thin film according to an embodiment of the present application;

[0022] Figure 3 is a mass spectrum diagram of complex 2 according to an embodiment of the present application; 1 H NMR nuclear magnetic resonance spectrum;

[0023] Figure 4 is a mass spectrum diagram of complex 4 according to an embodiment of the present application;

[0024] Figure 5 is an electrochemical test diagram of complex 2 according to an embodiment of the present application;

[0025] Figure 6 is a cross-sectional diagram of an OLED device according to an embodiment of the present application;

[0026] Figure 7 is a schematic diagram of an OLED device of a specific embodiment of the present application;

[0027] Figure 8 is a luminescence spectrum of a green light device using complex 2 according to an embodiment of the present application;

[0028] Figure 9 is a photoelectric conversion current efficiency diagram of a device using complex 2 according to an embodiment of the present application;

[0029] Figure 10 is a photoluminescence stability diagram of complex 2 according to an embodiment of the present application;

[0030] Figure 11 is a power efficiency diagram of photoelectric conversion of a device of complex 2 according to an embodiment of the present application;

[0031] Figure 12 is a luminescence stability diagram of a device of complex 2 according to an embodiment of the present application.

[0032] BRIEF DESCRIPTION OF DRAWINGS

[0033] 1000 organic optoelectronic device 1002 substrate 1004 anode layer

[0034] 1006 hole transport layer 1008 light emitting layer 1010 electron transport layer

[0035] 1012 metal cathode layer DETAILED DESCRIPTION

[0036] The endpoints of the ranges and any values disclosed herein are not limited to the precise values recited as exactly that endpoint. Any values that fall within common interpretations of the endpoints when the specification states a range of values will be interpreted as being included in that range in the application context. Individual values are included herein for numerical ranges irrespective of whether these values are recited or not.

[0037] As previously described, the first aspect of the present application provides a yellow-green phosphorescent divalent platinum complex, wherein the divalent platinum complex has a structure represented by Formula (I):

[0038]

[0039] wherein, in Formula (I):

[0040] R a , R b , R c , R d and R e each independently is present or absent, single or multiple substituents, and R a , R b , R c , R d and R e each independently is selected from a single atom substituent or a multiple atom substituent;

[0041] The single atom includes a hydrogen atom, an isotopic atom of hydrogen, or a halogen atom;

[0042] The multiple atom substituent includes an alkyl group, an aryl-substituted alkyl group, a fluorine-substituted alkyl group, an aryl group, an alkyl-substituted aryl group, an aryl-substituted aryl group, a cycloalkyl group, a cycloalkenyl group, a heteroaryl group, an alkenyl group, an alkynyl group, an amino group, a hydroxyl group, a mercapto group, a nitro group, a cyano group, an isocyano group, a sulfinyl group, a sulfonyl group, a carboxyl group, a hydrazine group, a mono-hydrocarbylamino group, a di-hydrocarbylamino group, a mono-arylamino group, a di-arylamino group, an alkoxy group, an aryloxy group, a haloalkyl group, an ester group, an alkoxycarbonyl group, an amido group, an alkoxycarbonylamino group, an aryloxycarbonylamino group, a sulfonamide group, a carbamoyl group, an alkylthio group, a urea group, a phosphoramide group, a silyl group, a polymer group, or the above substituents containing an isotopic atom.

[0043] The inventors of the present application found that: introducing pyridine-carbazole into the ligand structure of divalent platinum complex, the material has two excitation state characteristics, local ligand center and metal ligand transfer transition. The material is mainly local ligand center transition, the light emission is yellow-green light with a wave peak between 540-600 nm, which can be used as yellow-green light device of organic light emitting diode; under high concentration doping, the material can emit a wide spectrum, the half peak width of the light emission peak is greater than 70 nm, which can be used as white light device. The material also has the characteristics of high thermal decomposition temperature, quantum effect and the like, and is very stable in photoluminescence and device electroluminescence, and the application thereof can improve the application performance of the current green phosphor device.

[0044] According to a preferred embodiment, in formula (I):

[0045] R a , R b , R c , R d and R e are each independently selected from a hydrogen, deuterium, tritium, fluorine, chlorine, bromine or iodine atom.

[0046] According to a preferred embodiment, in formula (I):

[0047] R a , R b , R c , R d and R e are each independently selected from -CDH2, -CD2H, -CD3, -CDR1R2 or -CD2R1, wherein R1 and R2 are each independently selected from an alkyl, aryl-substituted alkyl, aryl, alkyl-substituted aryl, aryl-substituted aryl, cycloalkyl, cycloalkenyl, heteroaryl, alkenyl, alkynyl, amino, monoalkylamino, dialkylamino, monoarylamino, diarylamino, alkoxy, aryloxy, haloalkyl, ester, alkoxycarbonyl, amido, alkoxycarbonylamino, aryloxycarbonylamino, sulfonamide, carbamoyl, alkylthio, ureido, phosphonamidate or silyl group.

[0048] In the present application, it is necessary to point out that: for example, in the "-CDH2" group, "C" refers to carbon, and "D" refers to deuterium (D), an isotope of hydrogen, also called heavy hydrogen.

[0049] According to a preferred embodiment, in formula (I):

[0050] R a , R b , R c , R d and R eeach independently selected from the group consisting of methyl, deuterated 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, 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.

[0051] According to a preferred embodiment, the green phosphorescent divalent platinum complex is selected from at least one of the following:

[0052]

[0053]

[0054]

[0055]

[0056]

[0057]

[0058] According to a more preferred embodiment, the yellow-green phosphorescent divalent platinum complex is selected from at least one of the following:

[0059]

[0060] The method for preparing the divalent platinum complex is not particularly limited in the present application, and those skilled in the art can obtain suitable steps for synthesizing the complex according to the structural formula provided in the present application and known synthesis methods in the field of organic synthesis. The preparation methods of several specific compounds are exemplarily provided in the following of the present application, and those skilled in the art should not understand it as a limitation of the present application.

[0061] However, in order to make the yield and purity of the yellow-green phosphorescent divalent platinum complex of the present application higher, as described above, the second aspect of the present application further provides a method for preparing the aforementioned yellow-green phosphorescent divalent platinum complex, wherein the method comprises:

[0062] (1) contacting carbazolyl bipyridine represented by formula (II) and bispyridine represented by formula (III) under a protective gas to perform a first coupling reaction to obtain a compound represented by formula (IV) having carbazolyl bipyridine;

[0063] (2) contacting the compound represented by formula (IV) having carbazolyl bipyridine with boronic acid or amino substituent under a protective gas to perform a second coupling reaction to obtain a compound represented by formula (V); and

[0064]

[0065]

[0066] In formula (III), X is Br, I, Cl or OTf;

[0067] In formula (I), formula (II), formula (III), formula (IV) and formula (V), the definitions of the groups are the same as those described above.

[0068] In the present application, "OTf" refers to a trifluoromethanesulfonic acid group.

[0069] According to the present application, the synthesis flowchart of the divalent platinum complex is as follows:

[0070]

[0071] According to the present application, in step (1), the conditions of the first coupling reaction include a temperature of 100-200°C and a time of 24-60h.

[0072] According to the present application, the first coupling reaction further comprises being carried out in the presence of a catalyst, a ligand, a base and a solvent; wherein the catalyst is selected from one or more of tris(dibenzylideneacetone)dipalladium, tetrakis(triphenylphosphine)palladium and palladium acetate; the ligand is selected from one or more of 2-(di-tert-butylphosphino)biphenyl, 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl, 2-dicyclohexylphosphino-2',6'-dimethoxy-biphenyl and 1,1'-binaphthalene-2,2'-bisdiphenylphosphine; the base is selected from one or more of sodium tert-butoxide, potassium tert-butoxide and lithium tert-butoxide; and the solvent is dimethyl sulfoxide and / or N,N-dimethylformamide.

[0073] According to the present application, the molar ratio of the carbazolyl dipyridine of formula (II), the bipyridine of formula (III), the catalyst, the ligand and the base used in the present application is 1:(0.5-1.5):(0.01-0.1):(0.01-0.5):(0.5-5).

[0074] According to the present application, in step (2), the second coupling reaction is carried out under the conditions of a temperature of 100-200°C and a time of 24-60h.

[0075] According to the present application, the second coupling reaction further comprises being carried out in the presence of a catalyst, a ligand, a base and a solvent; wherein the catalyst is selected from one or more of tris(dibenzylideneacetone)dipalladium, tetrakis(triphenylphosphine)palladium, palladium acetate, cuprous iodide, cuprous bromide and cuprous chloride; the ligand is selected from one or more of tri-tert-butylphosphine, 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl, 2-dicyclohexylphosphino-2',6'-dimethoxy-biphenyl, tricyclohexylphosphine, 2,2,6,6-tetramethylheptanedione, N 1 ,N 2 - bis(5-methyl-[1,1'-biphenyl]-2-yl)oxalamide, trans-cyclohexanediamine, 1-methylimidazole, L-Proline; the base is selected from one or more of sodium tert-butoxide, potassium tert-butoxide, lithium tert-butoxide, cesium carbonate, potassium carbonate, potassium phosphate, cesium fluoride and potassium hydroxide; and 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.

[0076] According to the present application, the molar ratio of the carbazolyl dipyridine of formula (IV), the boronic acid or amino substituent, the catalyst, the ligand and the base used in the present application is 1:(0.8-5):(0.01-0.5):(0.1-1):(0.8-5).

[0077] According to the present application, in step (3), the conditions of the cyclometallation reaction include stirring at a temperature of 100-200°C for 36-100 hours in the presence of nitrogen.

[0078] According to the present application, the molar ratio of the compound of formula (V) to potassium chloroplatinate is 1:(0.8-2), and the concentration of acetic acid is 0.01-0.05 mmol / ml.

[0079] As mentioned above, the third aspect of the present application provides an application of the aforementioned yellow-green phosphorescent divalent platinum complex in an organic optoelectronic device.

[0080] As mentioned above, the fourth aspect of the present application provides an organic optoelectronic device, wherein 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, and at least one of the light-emitting layer, the electron transport layer and the hole transport layer comprises the aforementioned yellow-green phosphorescent divalent platinum complex.

[0081] Figure 6 is a cross-sectional view of an OLED device according to an embodiment of the present application; Figure 7 is a schematic view of an OLED device according to a specific example of the present application; in a preferred embodiment of the present application, as shown in Figure 6 and Figure 7 the OLED device can employ the divalent platinum complex of the present application as a light-emitting material. The OLED device 1000 comprises 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 host. The EIL refers to an electron injection layer, which can be considered as a part of the electron transport layer 1010. The HIL refers to a hole injection layer, which can be considered as a part of the hole transport layer 1006. The CPL is a cathode capping layer.

[0082] The complex 101 of the present application is used as a blue light-emitting dopant material in the light-emitting layer 1008.

[0083] According to a particularly preferred specific embodiment, the divalent platinum complex is comprised in the light-emitting layer.

[0084] More preferably, the divalent platinum complex is a light-emitting material, a host material or a guest material in the light-emitting layer.

[0085] Preferably, the thickness of the light-emitting layer is 30-100 nm, for example, it can be 50 nm.

[0086] In a preferred embodiment of the present application, the material of the light-emitting layer is a mixture of 3,3'-bis(9H-carbazol-9-yl)-1,1'-biphenyl or 2,6-di(9-carbazolyl)pyridine and the platinum(II) complex containing a carboline structure according to the present application in a weight ratio of 10:1.

[0087] In the present application, the anode material in the anode layer can be a conventional material in the art, for example, can be ITO (indium tin oxide).

[0088] In the present application, the hole transport layer can be a conventional material in the art, for example, can be PEDOT:PSS (poly 3,4-ethylenedioxythiophene / polystyrene sulfonate). Preferably, the thickness of the hole transport layer is 50-100 nm, preferably 70 nm.

[0089] In the present application, the material of the electron transport layer can be a conventional material in the art, for example, can be TmPyPB (3,3'-[5'-[3-(3-pyridyl)phenyl][1,1':3',1"-terphenyl]-3,3"-diyl]dipyridine). Preferably, the thickness of the electron transport layer is 30-80 nm, preferably 50 nm.

[0090] In the present application, the material of the metal cathode layer can be a conventional material in the art, for example, can be Al / Liq (aluminum and 8-hydroxyquinoline lithium), wherein the thickness of the Al layer can be 50-150 nm, preferably 100 nm, and the thickness of the Liq can be 0.5-2 nm, preferably 1 nm.

[0091] When the divalent platinum complex is used as a doping material in an OLED device, the device is prepared by a spin coating method, and the structure is ITO / PEDOT:PSS (70 nm) / host material:divalent platinum complex (1000-x:x, 40 nm) / DPEPO (10 nm) / TmPyPB (50 nm) / Liq (1 nm) / Al (100 nm).

[0092] In the specific embodiments described above, the light-emitting layer 1008 may contain one or more divalent platinum complexes provided by the present invention, and may selectively include 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 material of the light-emitting layer 1008, and the emission energy (optical bandgap) of the light-emitting layer 1008 can be tuned as described above by tuning the electronic structure of the emission divalent platinum complex 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.

[0093] In this invention, in order to improve the luminous efficiency of organic optoelectronic devices, preferably, a hole blocking layer is also provided in the hole transport layer. The material of the hole blocking layer can be a conventional material in the art, such as DPEPO (bis[2-((oxo)diphenylphosphino)phenyl] ether). Preferably, the thickness of the hole blocking layer is 30-60 nm, and more preferably 40 nm.

[0094] OLED device structure can be Figure 7 A charge-blocking layer, such as a hole-blocking layer (HBL) or an electron-blocking layer (EBL), is added to the basic structure to improve device efficiency. The device structure is ITO / P-doping HT / HTL / EBL / Main material: divalent 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. BD refers to the green light-doping material, i.e., the platinum complex of this invention.

[0095] In addition, the complexes of the present invention can also be used in the following common device structures:

[0096] ITO / HATCN (10 nm) / NPD (40 nm) / TAPC (10 nm) / 2,6-mCPy: divalent platinum complex / DPPS (40 nm) / LiF / Al; ITO / HATCN (10 nm) / NPD (40 nm) / TAPC (10 nm) / TAPC: PO15: divalent platinum complex (25 nm) / PO15 (10 nm) / BmPyPB / LiF / Al; ITO / HATCN (10 nm) / NPD (40 nm) / mCBP: divalent platinum complex / BAlq (10 nm) / Alq (30 nm) / LiF / Al; ITO / HATCN (10 nm) / NPD (40 nm) / TAPC (10 nm) / host material: divalent platinum complex / DPPS (40 nm) / BmPyPB or TmPyPB / LiF / Al; ITO / HATCN (10 nm) / HTL / EBL / bipolar host material: divalent platinum complex / bipolar host material / BmPyPB or TmPyPB / LiF / Al; divalent platinum complex / DPPS (40 nm) / BmPyPB or TmPyPB / LiF / Al; ITO / HATCN (10 nm) / NPD (40 nm) / TrisPCz (10 nm) / mCBP: divalent platinum complex (25 nm) / Balq (10 nm) or mCBT (8 nm) / BPyTP (40 nm) / LiF / Al, and the like.

[0097] The present application will be described in detail below by way of examples.

[0098] Example 1

[0099] This example is directed to the preparation of complex 2 and its structural characterization.

[0100] (1) Synthesis of intermediate 9-(6'-chloro-[2,4'-bipyridine]-2'-yl)-2-(pyridin-2-yl)-9H-carbazole:

[0101]

[0102] To a 48 mL flask was added 2',6'-dichloro-2,4'-bipyridine (1.2 mmol), 2-(pyridin-2-yl)-9H-carbazole (1 mmol), tris(dibenzylideneacetone)dipalladium (0.05 mmol), 2-(di-tert-butylphosphine)biphenyl (0.1 mmol), sodium tert-butoxide 2 mmol) and toluene (10 mL), the resulting mixture was bubbled with nitrogen and heated with stirring overnight; cooled to room temperature, the reaction was quenched with water, extracted with ethyl acetate, the organic phases were combined, washed with an appropriate amount of saturated aqueous sodium chloride solution and dried over anhydrous sodium sulfate; the solvent was removed under reduced pressure, the resulting crude product was purified by column chromatography on silica gel using petroleum ether: ethyl acetate = 10: 1 as eluent to obtain 9-(6'-chloro-[2,4'-bipyridine]-2'-yl)-2-(pyridin-2-yl)-9H-carbazole as a yellow solid; 1 H NMR (400 MHz, CDC13) δ 8.78 (d, J = 4.7 Hz, 1H), 8.70 (d, J = 4.1 Hz, 1H), 8.59 (d, J = 0.9 Hz, 1H), 8.27 (d, J = 1.0 Hz, 1H), 8.20 (d, J = 8.2 Hz, 1H), 8.15 (d, J = 7.6 Hz, 1H), 7.99 (dd, J = 8.1, 1.3 Hz, 2H), 7.94 (d, J = 8.3 Hz, 1H), 7.87 (dd, J = 8.3, 4.7 Hz, 3H), 7.78 (td, J = 7.7, 1.8 Hz, 1H), 7.54 - 7.47 (m, 1H), 7.41 (dd, J = 8.4, 5.0 Hz, 2H), 7.37 (t, J = 7.5 Hz, 1H), 7.23 (ddd, J = 7.3, 4.9, 1.0 Hz, 1H).

[0103] (2) Synthesis of intermediate 9-(6'-(prop-1-en-2-yl)-[2,4'-bipyridine]-2'-yl)-2-(pyridin-2-yl)-9H-carbazole:

[0104]

[0105] Into a 50 mL round bottom flask was added 9-(6'-chloro-[2,4'-bipyridine]-2'-yl)-2-(pyridin-2-yl)-9H-carbazole (1 mmol), 4,4,5,5-tetramethyl-2-(prop-l-en-2-yl)-l,3,2-dioxaborolane (2.5 mmol), tetrakis(triphenylphosphine)palladium (0.05 mmol), potassium carbonate K2CO3(1.5 mmol), ethyleneglycol dimethyl ether (1 mL) and water (1 mL), the resulting mixture was bubbled with nitrogen and heated with stirring overnight; cooled to room temperature, quenched with water, extracted with ethyl acetate, combined the organic phase, washed with a suitable amount of saturated aqueous sodium chloride solution and dried over anhydrous sodium sulfate; the solvent was removed by distillation under reduced pressure, the resulting crude product was purified by column chromatography on silica gel using petroleum ether: ethyl acetate = 15: 1 as eluent to give 9-(6'-(prop-l-en-2-yl)-[2,4'-bipyridine]-2'-yl)-2-(pyridin-2-yl)-9H-carbazole as a white solid.

[0106] (3) Preparation of intermediate 9-(6'-isopropyl-[2,4'-bipyridine]-2'-yl)-2-(pyridin-2-yl)-9H-carbazole, synthesis of ligand L2:

[0107]

[0108] Into a 50 mL round bottom flask was added 9-(6'-(prop-l-en-2-yl)-[2,4'-bipyridine]-2'-yl)-2-(pyridin-2-yl)-9H-carbazole (1 mmol), palladium on carbon (0.005 mmol), tetrahydrofuran (10 mL) and methanol (5 mL), the resulting mixture was stirred at room temperature under a hydrogen atmosphere; after the reaction was complete, the reaction system was subjected to suction filtration and washed with a large amount of ethyl acetate, the filtrate obtained by suction filtration was subjected to solvent removal by distillation under reduced pressure, the resulting crude product was purified by column chromatography on silica gel using petroleum ether: ethyl acetate = 25: 1 as eluent to give ligand L2 as a white solid; 1H NMR (400 MHz, DMSO-d6) δ 8.78 (ddd, J = 4.7, 1.8, 0.9 Hz, 1H), 8.72 (d, J = 1.0 Hz, 1H), 8.64 (ddd, J = 4.7, 1.8, 0.8 Hz, 1H), 8.37 (d, J = 8.3 Hz, 1H), 8.32 (d, J = 7.5 Hz, 1H), 8.28 (dd, J = 4.6, 3.4 Hz, 2H), 8.08 (dd, J = 8.2, 1.4 Hz, 2H), 8.05 - 7.99 (m, 2H), 7.89 (dd, J = 11.1, 5.1 Hz, 2H), 7.56 - 7.51 (m, 2H), 7.41 - 7.36 (m, 1H), 7.34 (ddd, J = 7.4, 4.8, 0.9 Hz, 1H), 3.32 - 3.28 (m, 1H), 1.43 (d, J = 6.9 Hz, 6H).

[0109] (4) Synthesis of complex 2:

[0110]

[0111] To a 350 mL flask was added ligand L2, potassium chloroplatinate (0.55 mmol) and acetic acid (50 mL), the resulting mixture was bubbled with nitrogen, after stirring, heated; cooled to room temperature, the reaction was quenched with water, extracted with dichloromethane, the organic phase was combined, washed with saturated sodium chloride aqueous solution, and dried over anhydrous sodium sulfate. The solvent was removed by distillation under reduced pressure, and the obtained crude product was purified by silica gel column chromatography, eluent dichloromethane:methanol = 400:1, to obtain yellow solid complex 2; 1 H NMR (300 MHz, DMSO) δ 8.89 (m, 1H), 8.56 (m, 1H), 8.40 - 8.20 (m, 3H), 8.01 - 7.95 (m, 2H), 7.85 (d, J = 8.1 Hz, 2H), 7.50 - 7.30 (m, 3H), 7.22 (s, 1H), 6.96 (s, 1H), 3.44 (m, 1H), 1.32 (d, J = 6.9 Hz, 6H). MS (ESI) 634.42 [M+1] + .

[0112] Example 2

[0113] This example is directed to the preparation of complex 4 and its structural characterization.

[0114] (1) Synthesis of intermediate 2-((2-mesityl-6-(1H-pyrazol-1-yl)pyridin-4-yl)oxy)-9-(pyridin-2-yl)-9H-carbazole, i.e. L4:

[0115]

[0116] Into a 15 mL sealed tube was added 9-(6'-chloro-[2,4'-bipyridine]-2'-yl)-2-(pyridin-2-yl)-9H-carbazole (1 mmol), phenylboronic acid, tris(dibenzylideneacetone)dipalladium (0.1 mmol), tricyclohexylphosphonium (0.8 mmol), potassium hydroxide (2.5 mmol) and 1,4-dioxane (2 mL). The resulting mixture was bubbled with nitrogen and stirred at room temperature overnight. The reaction was quenched with water and extracted with ethyl acetate. The organic phase was combined and washed with saturated aqueous sodium chloride solution and dried over anhydrous sodium sulfate. The solvent was removed under reduced pressure. The resulting crude product was purified by silica gel column chromatography using petroleum ether: ethyl acetate = 25: 1 as eluent to give a white solid;

[0117] (2) Synthesis of complex 4:

[0118]

[0119] Into a 350 mL sealed tube was added ligand L4 (0.5 mmol), potassium chloroplatinate (0.55 mmol) and acetic acid HOAc (55 mL). The resulting mixture was bubbled with nitrogen and stirred at room temperature for 24 hours. The reaction was quenched with water and extracted with dichloromethane. The organic phase was combined and washed with saturated aqueous sodium chloride solution and dried over anhydrous sodium sulfate. The solvent was removed under reduced pressure. The resulting crude product was purified by silica gel column chromatography using dichloromethane: methanol = 400: 1 as eluent to give a yellow solid complex 4. 1 H NMR (300 MHz, DMSO) δ 8.81-8.77 (m, 2H), 8.60 (m, 2H), 8.05-7.80 (m, 4H), 7.60-7.20 (m, 6H), 7.20 (s, 1H), 6.90 (s, 1H). MS (ESI) 668.48 [M+1] + .

[0120] Example 3

[0121] This example is directed to the preparation of complex 8 and its structural characterization.

[0122] (1) Synthesis of intermediate 9-(6'-(9H-carbazol-9-yl)-[2,4'-bipyridine]-2'-yl)-2-(pyridin-2-yl)-9H-carbazole, i.e. L8

[0123]

[0124] Into a 15 mL vial was placed 9-(6'-chloro-[2,4'-bipyridine]-2'-yl)-2-(pyridin-2-yl)-9H-carbazole (1 mmol), carbazole (2 mmol), tris(dibenzylideneacetone)dipalladium (0.05 mmol), 2-(di-tert-butylphosphine)biphenyl (0.1 mmol), sodium tert-butoxide (NaoBu-t) (2 mmol) and 1,4-dioxane (2 mL). The resulting mixture was bubbled with nitrogen and stirred at room temperature overnight. The reaction was quenched with water and extracted with ethyl acetate. The organic phases were combined, washed with saturated aqueous sodium chloride solution and dried over anhydrous sodium sulfate. The solvent was removed under reduced pressure and the resulting crude product was purified by column chromatography on silica gel using petroleum ether: ethyl acetate = 5: 1 as eluent to give ligand L8 as a white solid.

[0125] (2) Synthesis of complex 8:

[0126]

[0127] Into a 350 mL vial was placed ligand L8 (0.5 mmol), potassium chloroplatinate (0.55 mmol) and acetic acid (50 mL). The resulting mixture was bubbled with nitrogen and stirred at room temperature overnight. The reaction was quenched with water and extracted with dichloromethane. The organic phases were combined, washed with saturated aqueous sodium chloride solution and dried over anhydrous sodium sulfate. The solvent was removed under reduced pressure and the resulting crude product was purified by column chromatography on silica gel using dichloromethane: methanol = 600: 1 as eluent to give complex 8 as a yellow solid; MS (ESI) 757.76 [M+1] + .

[0128] Example 4

[0129] This example is directed to the preparation of complex 9 and its structural characterization.

[0130] (1) Synthesis of intermediate N,N-diphenyl-6'-(2-(pyridin-2-yl)-9H-carbazol-9-yl)- [2,4'-bipyridine]-2'-amine, ligand L9:

[0131]

[0132] Into a 15 mL vial was added 9-(6'-chloro-[2,4'-bipyridine]-2'-yl)-2-(pyridin-2-yl)-9H- carbazole (1 mmol), diphenylamine (1.5 mmol), tris(dibenzylideneacetone)dipalladium Pd2(dba)3(0.1 mmol), 2-(di-tert-butylphosphino)biphenyl (0.2 mmol), sodium tert-butoxide (2 mmol) and 1,4-dioxane (2 mL). The resulting mixture was bubbled with nitrogen and stirred at room temperature overnight. The reaction was quenched with water and extracted with ethyl acetate. The organic phase was combined and washed with saturated aqueous sodium chloride solution and dried over anhydrous sodium sulfate. The solvent was removed under reduced pressure. The resulting crude product was purified by silica gel column chromatography using petroleum ether: ethyl acetate = 5: 1 as eluent to give ligand L9 as a white solid.

[0133] (2) Synthesis of complex 9:

[0134]

[0135] Into a 350 mL vial was added ligand L9 (0.5 mmol), potassium chloroplatinate (0.55 mmol) and acetic acid (50 mL). The resulting mixture was bubbled with nitrogen and stirred at room temperature overnight. The reaction was quenched with water and extracted with dichloromethane. The organic phase was combined and washed with saturated aqueous sodium chloride solution and dried over anhydrous sodium sulfate. The solvent was removed under reduced pressure. The resulting crude product was purified by silica gel column chromatography using dichloromethane: methanol = 800: 1 as eluent to give complex 9 as a yellow solid; MS (ESI) 759.61 [M+1] + .

[0136] Test Example

[0137] This test example is directed to illustrate the luminescent property characterization of the complexes.

[0138] Representative data of the color purity of the emitters can be obtained from the thin film emission spectra prepared using 5% and 50% PMMA (polymethyl methacrylate) dichloromethane solutions.

[0139] Table 1 is the emission spectrum data of the divalent platinum complexes prepared in Examples 1-4. In Table 1, λ is the peak wavelength, CIE (x, y) is the chromaticity coordinate parameter according to the International Commission on Illumination standard, and the CRI index is measured according to the international standard. The peak wavelength of the divalent platinum complex 2, the divalent platinum complex 4, the divalent platinum complex 8, and the divalent platinum complex 9 prepared in Examples 1-4 of the present application is between 540-570, which meets the application requirements of yellow-green; at a doping concentration of 50%, the white light emission region is from 450-650 nm, which can meet the application requirements of lighting and display.

[0140] Table 1

[0141]

[0142] in addition, Figure 1 The emission spectra of divalent platinum complex 2 in solution and thin film are shown. Under 420 nm UV excitation, the emission wavelengths of the complex in dichloromethane solution and polymethyl methacrylate (PMMA) are between 540-565 nm, with both complexes in the yellow-green region. Figure 1 The emission spectrum of divalent platinum complex 2 in PMMA film shows an emission peak of 543 nm and a half-width of 82 nm, which is a very good yellow-green light emitting material.

[0143] Figure 2 The UV-Vis absorption spectra of the aforementioned divalent platinum complex 2 in dichloromethane solution are shown. According to the absorption spectra, both platinum complexes exhibit very strong absorption in the 250-420 nm range. The absorption below 330 nm can be attributed to π-π* transitions centered on the ligand within the complex, while the absorption peaks above 370 nm can be attributed to valence state transfer transitions (MLCT) between the central metal ion and the ligand. These transitions are very strong in this type of divalent platinum complex, with peak intensity reaching half that of the ligand absorption peak and extinction coefficients reaching 2.5 × 10⁻⁶. -4 ·M -1 ·cm -1 This demonstrates that the energy absorption of this type of molecule is highly efficient, making it a preferred molecular structure for doping materials. Wavelengths below 280 nm represent π-π* transitions allowed by the pyridine ring spin, while 280-370 nm represents π-π* transitions in the carbazole ligand moiety. Absorption above 370 nm originates from d-π* transitions in the metal-to-ligand transfer state.

[0144] The band gaps and related optical properties of the above-mentioned divalent platinum complexes 2, 4, 8, and 9 are characterized as follows:

[0145] The band gap value of the material (E) g The LUMO and HOMO values ​​were measured using cyclic voltammetry (CV). The entire test was conducted on a CHI600D electrochemical workstation (Shanghai Chenhua Instrument Co., Ltd.) in a glove box (Lab2000, Etelux). A three-electrode system was constructed using a Pt column as the working electrode, Ag / AgCl as the reference electrode, and a Pt wire as the auxiliary electrode. The medium used in the test was a 0.1M tetrabutylammonium hexafluorophosphate dimethylformamide solution. Ferrocene was added as an internal standard for all measured potentials. In Table 2, λ is the peak wavelength of the divalent platinum complex dissolved in dichloromethane, FWHM is its full width at half maximum, and the triplet photon energy (E) of the material is...T1 ) calculated from formula 1240 / λ 0-0 0-0 77K, in electron volt (eV).

[0146] Table 2 shows the energy level data of the divalent platinum complexes prepared in Examples 1-4. From the data in Table 2, it can be seen that the energy level of the HOMO orbit of divalent platinum complex 4, divalent platinum complex 8, and divalent platinum complex 9 is lower than that of divalent platinum complex 2, indicating that a bulky aryl group can lower the HOMO energy level of the material. The triplet energy of the four divalent platinum complexes is 2.22-2.29 eV, which is mainly related to the structure of the mother nucleus, indicating that the triplet state radiation transition is consistent under low temperature conditions, i.e., when the molecular thermal motion is limited. This also indicates that the energy level and emission spectrum of these divalent platinum complexes can be adjusted within a small range by introducing substituents, so as to obtain an optimal luminescence spectral range.

[0147] Figure 5 The cyclic voltammogram of the electrochemical analysis of divalent platinum complex 2 is shown. The oxidation / reduction half-potential E ox and E re of divalent platinum complex 2 is 1.11 and -1.67 V, respectively, and the oxidation / reduction half-potential E Fc / Fc+ of the reference ferrocene is 0.70 / 0.61 V, respectively. The HOMO and LUMO values of divalent platinum complex 2 can be obtained by formula E HOMO / LUMO =-[E ox / re,onset -E (Fc / Fc+) +4.8] eV, which are -5.21 eV and -2.52 eV, respectively. The electrochemical method measurement values of the HOMO / LUMO of other examples are shown in Table 2.

[0148] Table 2

[0149] Complex E HOMO / eV]]> E LUMO / eV]]> Eg / eV λ / nm E T1 / eV]]> Complex 2 -5.21 -2.52 2.69 542 2.29 Complex 4 -5.34 -2.60 2.74 552 2.25 Complex 8 -5.38 -2.57 2.81 559 2.22 Complex 9 -5.38 -2.66 2.72 556 2.23

[0150] In addition, Figure 3 The mass spectrum of divalent platinum complex 2 is shown, indicating that the compound is successfully prepared. 1 The HNMR spectrum of divalent platinum complex 2 is shown, indicating that the compound is successfully prepared and purified by the method provided in the present patent, and thus, the present example indicates that the small molecule is effective and feasible in practical application and preparation process.

[0151] In addition, Figure 4 The mass spectrum of divalent platinum complex 2 is shown, indicating that the compound is successfully prepared.

[0152] In addition, Figure 5 ​Electrochemical test characterization of the above bivalent platinum complex 2 is shown in the figure, which shows a reversible oxidation peak, indicating that the complex 2 has good stability under oxidation conditions.

[0153] Application Example

[0154] Performance comparison experiment of light emitting devices prepared by using bivalent platinum complexes prepared in Examples 1-4.

[0155] Figure 8 The luminescence spectrum of the device using the bivalent platinum complex 2 is shown. The device structure is ITO / HATCN (10 nm) / NPD (40 nm) / TAPC (10 nm) / 2,6-mCPy:5% complex 2 (25 nm) / 2,6-mCPy (10 nm) / TmPyPB (30 nm) / LiF (1 nm) / Al (100 nm). The electroluminescence spectrum of the device doped with 5% complex according to the luminescence layer shows that the luminescence peak is red-shifted by 5 nm relative to its photoluminescence peak in PMMA medium, and the half-peak width becomes a little smaller, maintaining the luminescence characteristics of the luminescent bivalent platinum complex 2 itself. The calculated chromaticity coordinate value is CIE (0.42, 0.54), indicating that this device is suitable for use as a yellow-green light emitting device.

[0156] Figure 9 The photoelectric conversion current efficiency curve of the device using the bivalent platinum complex 2 of the present application is shown. The device structure is ITO / HATCN (10 nm) / NPD (40 nm) / TAPC (10 nm) / 2,6-mCPy:5% complex 2 (25 nm) / 2,6-mCPy (10 nm) / TmPyPB (30 nm) / LiF (1 nm) / Al (100 nm). Figure 9 The photoelectric conversion current efficiency curve of the device using the complex 2 is shown to be very stable. From 0 mA / cm 2 to 20 mA / cm 2 The current roll-off is less than 5% under the change of current density, and the device of the doped material has high efficiency, in which the 5% doped device has a current efficiency of 20.45 cd / A at 10 mA / cm 2 , indicating that the complex 2 as a yellow-green light emitting doped material has high efficient and stable light conversion performance.

[0157] Figure 10 The photoluminescence decay curve over time of the bivalent platinum complex 2 of the present application is shown. Figure 10The change in luminescence intensity of a 5 wt% doped polystyrene (PS) film using the divalent platinum complex 2 of this invention under 375 nm UV light irradiation over time is shown. This indicates that the device using complex 2 maintains a spectral attenuation of no more than 2% for 60 minutes under strong luminescence conditions, and a spectral attenuation of less than 8% over 6 hours. This experiment demonstrates the excellent luminescence stability of the complex. The attenuation test was conducted using 50 mW / cm² light. 2 A stable polystyrene polymer film doped with 5% of the material was irradiated with ultraviolet light, and the intensity of photoluminescence was recorded. The relationship between the luminescence decay of the compound and time was then obtained. The test results indicate that the complex 2 has excellent photostability and is well-suited for device fabrication.

[0158] Figure 11 The power efficiency of a device fabricated using the divalent platinum complex 2 of this invention in photoelectric conversion is shown. The device structure is ITO / HATCN (10nm) / NPD (40nm) / TAPC (10nm) / 2,6-mCPy:5% complex 2 (25nm) / 2,6-mCPy (10nm) / TmPyPB (30nm) / LiF (1nm) / Al (100nm), with complex 2 comprising 2% and 5% of the emitting layer material. The power efficiency cutoff in the 2% doped device is 1629 cd / m². 2 The brightness is 15.4 lm / W, and the power efficiency cutoff in a 5% doped device is 1039 cd / m². 2 The brightness is 20.7 lm / W, indicating that complex 2, as a yellow-green light-emitting dopant, has efficient and stable light conversion performance.

[0159] Figure 12 The image shows the decay curve of photoluminescence over time for the device fabricated using the divalent platinum complex 2 of this invention. The device structure is ITO / HATCN (10nm) / NPD (40nm) / TAPC (10nm) / 2,6-mCPy:5% complex 2 (25nm) / 2,6-mCPy (10nm) / TmPyPB (30nm) / LiF (1nm) / Al (100nm), composed of... Figure 12 It can be seen that the electroluminescence decay of the device based on complex 2 is slower, resulting in better device stability. LT97@50mA / cm 2 The lifetime is 130 minutes, which indicates that the device doped with complex 2 has great stability.

[0160] In addition, the performance data of the light-emitting devices prepared using the divalent platinum complexes prepared in Examples 1-4 above are shown in Table 3.

[0161] Table 3

[0162]

[0163] The luminescent performance data of the luminescent devices prepared by the divalent platinum complexes prepared in Examples 1-4 are shown in Table 3. The electroluminescent wavelength of the luminescent device is mainly determined by the photoluminescence of the divalent platinum complex itself, and the purity of the photoluminescence spectrum of the divalent platinum complex itself is directly related to the spectral purity of the electroluminescence. Under the same conditions, the efficiency of the luminescent device is also consistent with the luminescence quantum efficiency of the divalent platinum complex itself, and the color purity of the luminescence of the luminescent device is directly related to the spectral color purity of the emitted light under photoexcitation of the doped material itself. By comparing the electroluminescence spectrum of the divalent platinum complex luminescent device with the photoluminescence spectrum in the thin film, it can be seen that compared with the photoluminescence spectrum in the thin film, the electroluminescence spectrum of the luminescent device has a slight red shift, but the peak wavelength is still in the yellow-green light region (540-565 nm), and the calculated chromaticity coordinates show that the luminescent device belongs to a yellow-green light luminescent device.

[0164] The above describes the preferred embodiments of the present application, but the present application is not limited thereto. Within the technical concept of the present application, various simple modifications can be made to the technical solutions of the present application, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be considered as disclosed by the present application and fall within the protection scope of the present application.

Claims

1. A yellow-green phosphorescent d8 platinum complex, characterized in that, The divalent platinum complex has a structure shown in formula (I): In formula (I), X is Br, I, Cl or OTf; R a , R b , R c , R d and R e are each independently selected from methyl, deuterated 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, 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.

2. The bivalent platinum complex of claim 1, wherein, The divalent platinum complex is selected from at least one of the following:

3. The bivalent platinum complex of claim 2, wherein, The divalent platinum complex is selected from at least one of the following:

4. A process for the preparation of the green-yellow phosphorescent divalent platinum complex according to any one of claims 1 to 3, characterized in that, The method comprises: (1) contacting carbazolyl bipyridine shown in formula (II) and bispyridine shown in formula (III) under protective gas to perform a first coupling reaction to obtain a compound with carbazolyl bipyridine shown in formula (IV); (2) contacting the compound with carbazolyl bipyridine shown in formula (IV) with boronic acid or amino substituent under protective gas to perform a second coupling reaction to obtain a compound shown in formula (V); (3) performing ring metallation reaction on the compound shown in formula (V) in the presence of potassium chloroplatinite and acetic acid to obtain the yellow-green phosphorescent divalent platinum complex shown in formula (I); In formula (III), X is Br, I, Cl or OTf; In formula (I), formula (II), formula (III), formula (IV) and formula (V), the definitions of the groups are the same as those in any one of claims 1-3.

5. The method of claim 4, wherein, In step (1), the conditions of the first coupling reaction include: temperature is 100-200℃, time is 24-60h; And / or, the first coupling reaction further comprises being performed in the presence of a catalyst, a ligand, a base and a solvent; And / or, the catalyst is selected from one or more of tris(dibenzylideneacetone)dipalladium, tetrakis(triphenylphosphine)palladium and palladium acetate; And / or, the ligand is selected from one or more of 2-(di-tert-butylphosphino)biphenyl, 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl, 2-dicyclohexylphosphino-2',6'-dimethoxy-biphenyl and 1,1'-binaphthalene-2,2'-bisdiphenylphosphine; And / or, the base is selected from one or more of sodium tert-butoxide, potassium tert-butoxide and lithium tert-butoxide; And / or, the solvent is dimethyl sulfoxide and / or N,N-dimethylformamide; And / or, the molar ratio of the amount of carbazolyl bipyridine shown in formula (II), bispyridine shown in formula (III), the catalyst, the ligand and the base is 1:(0.5-1.5):(0.01-0.1):(0.01-0.5):(0.5-5).

6. The method of claim 4, wherein, In step (2), the conditions of the second coupling reaction include: temperature is 100-200℃, time is 24-60h; And / or, the second coupling reaction further comprises being performed in the presence of a catalyst, a ligand, a base and a solvent; And / or, the catalyst is selected from one or more of tris(dibenzylideneacetone)dipalladium, tetrakis(triphenylphosphine)palladium, palladium acetate, cuprous iodide, cuprous bromide and cuprous chloride; and / or the ligand is selected from tri-tert-butylphosphine, 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl, 2-dicyclohexylphosphino-2',6'-dimethoxy-biphenyl, tricyclohexylphosphine, 2,2,6,6-tetramethylheptanedione, N 1 , 2 - one or more of bis(5-methyl-[1,1 '-biphenyl]-2-yl)oxal amide, trans-cyclohexanediamine, 1 -methylimidazole and L-Proline; And / or, the base is selected from one or more of sodium tert-butoxide, potassium tert-butoxide, lithium tert-butoxide, cesium carbonate, potassium carbonate, potassium phosphate, cesium fluoride and potassium hydroxide; And / or, 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; And / or, the molar ratio of the carbazole dipyridine, boronic acid or amino substituent of formula (IV), the catalyst, the ligand and the base is 1:(0.8-5):(0.01-0.5):(0.1-1):(0.8-5).

7. The method of claim 4, wherein, In step (3), the conditions of the cyclometallation reaction include stirring at a temperature of 100-200°C for 36-100h in the presence of nitrogen; And / or, the molar ratio of the compound of formula (V) and potassium chloroplatinate is 1:(0.8-2).

8. Use of the yellow-green phosphorescent divalent platinum complex according to any one of claims 1-3 in an organic optoelectronic device.

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, and at least one of the light emitting layer, the electron transport layer and the hole transport layer comprises the yellow-green phosphorescent divalent platinum complex according to any one of claims 1-3.

10. The organic optoelectronic device according to claim 9, wherein, The yellow-green phosphorescent divalent platinum complex is contained in the light emitting layer.

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

Images