Divalent platinum complex, preparation method and application thereof, and organic photoelectric device

Abstract

The invention belongs to the technical field of photoelectric materials, and discloses a bivalent platinum complex, a preparation method and application thereof and an organic photoelectric device. The bivalent platinum complex has a structure as shown in a formula (I), wherein Ra is substituted or unsubstituted alkyl of three or more C; rb is a substituted or unsubstituted alkyl group; rc, Rd and Re are the same or different and are independently selected from monatomic substituent groups or polyatomic substituent groups; the monatomic substituent comprises hydrogen atoms and isotope atoms or halogen atoms thereof; the polyatomic substituent groups comprise one or more of substituted or unsubstituted alkyl groups, substituted or unsubstituted aryl groups, alkyl-substituted aryl groups, aryl-substituted aryl groups, cycloalkyl groups, cycloalkenyl groups, heteroaryl groups, alkenyl groups, alkynyl groups, alkoxy groups, aryloxy groups, ester groups, silane groups, polymer groups and the substituent groups containing isotope atoms; # imgabs0 #

Description

Technical Field

[0001] The present invention belongs to the technical field of optoelectronic materials, and in particular, relates to a divalent platinum complex, a preparation method and application thereof, and an organic optoelectronic device. Background Art

[0002] Organic Light-Emitting Diodes (OLEDs) materials can emit light of different colors when powered, and have great prospects in flat panel displays and solid-state lighting applications. Products related to molecular-level semiconductor technology represented by (OLED) technology have many advantages in terms of applicability and low energy consumption. OLED luminescence technology has been commercialized in display and lighting. Based on the principle of three primary colors of light, OLED as a light source needs to have three primary colors of red, green and blue, or a wide spectrum of white light, in order to achieve white light illumination and full-color display applications. At present, the efficiency and life indicators of red and green phosphorescent OLED devices have reached or exceeded the standards for industrial applications, but the life of blue and white light devices has always been a shortcoming in the development of the OLEDs industry. Excellent blue emitters and white light emitters based on high-efficiency blue emitters are particularly scarce. Therefore, blue phosphorescent materials are the most urgent problem to be solved in the development of OLEDs.

[0003] Compared with red and green light-emitting materials, high-efficiency phosphorescent blue light-emitting material molecules with stable structures and suitable emission spectra are more scarce and in great demand. Compared with the lowest triplet excited state energy of red and green phosphors, the lowest triplet excited state energy of blue phosphors is very high, which means that the lowest triplet excited state energy of the main material of the blue device must be higher. Therefore, the types of organic optoelectronic devices that can reach the blue light emission range are relatively limited. Correspondingly, it is more difficult to regulate the appropriate blue light spectrum so that the blue light-emitting device can show excellent performance during the light emission process. The latest research shows that platinum complex luminescent materials have advantages in the application of blue light devices. This is mainly because platinum complex materials have better spectral regulation performance and can achieve stable blue phosphorescence with a narrow spectrum. In addition, based on the study of the relationship between the structure and luminescence of organic light-emitting molecules (Ultrapure Blue Phosphorescent Organic Light-Emitting Diodes Employing a Twisted Pt(II) Complex, Yumeng Chen, Chunyue Qian, Ke Qin, Hongbo Li, Xiaobo Shi, Zhenzhong Lu, *Huili Ma, Tianshi Qin, Xiao-Chun Hang, Wei Huang, ACS Appl. Mater. Interfaces 2021, 13, 52833-52839), it was found that after introducing steric groups at some key sites of molecules with the same core structure, molecules with a highly twisted quasi-planar structure can be obtained, thereby inhibiting the intermolecular interaction and achieving a high-efficiency and stable single-molecule blue phosphorescent luminescence effect, thereby realizing a high-efficiency blue phosphorescent device.

[0004] In order to obtain better device effects, it is necessary to achieve a balance in the transmission of electrons and holes in the light-emitting layer as much as possible during the operation (power-on) of the device. Therefore, the light-emitting layer of the organic optoelectronic device and its light-emitting molecules need to have the ability to capture both holes and electrons. However, the weakness of organic light-emitting devices is that the hole transmission capacity is generally greater than the electron transmission capacity. The difference can reach 1 to 3 orders of magnitude from the comparison of mobility. Therefore, in the design of light-emitting materials, adding units with electron transmission capacity can increase the electron transmission and injection capacity, thereby obtaining better device effects. Among them, nitrogen-containing heterocyclic aromatic hydrocarbons are very excellent electron acceptor units. Representative materials include 1,3-bis(3,5-dipyrid-3-yl-phenyl)benzene (BmPyPB). The electron mobility of the two materials can reach 10 -4 ~10 -3 cm 2 V -1 s-1 The order of magnitude is very good for commercial electron transport materials. Introducing fragments that enhance electron migration and injection into luminescent materials is beneficial to the balance of charge capture of the material in the device. Therefore, similar concepts can be used in the design of OLED luminescent materials. For example, introducing nitrogen heteroaromatic groups with good electron transport into fluorescent materials can achieve excellent device effects. Especially in blue phosphorescent light-emitting devices, the introduction of non-coordinated pyridine units in the ligand can obtain ultra-long device stability and excellent luminescence effects, which is better than the overall effect of phenyl coordination. Summary of the invention

[0005] The purpose of the present invention is to overcome the problem that the OLED devices in the prior art lack stable and efficient blue light emitting materials or phosphorescent light emitting materials, and to provide a divalent platinum complex and a preparation method and application thereof, as well as an organic photoelectric device; the present invention generates a substituted pyrazole ligand by cyclization of a nitrile and a symmetrical diketone, and finally prepares a complex having a steric hindrance effect on the pyrazole structure; the ligand structure of the divalent platinum complex contains a pyrazole coordination structure with a large alkyl substituent, and these two structures can inhibit the interaction between molecules and have better single-molecule blue light emitting properties in a solid medium, so that this type of new compound has the effect of a narrow blue phosphorescent emission spectrum, which will be able to promote the emission color and improve the performance of blue phosphorescent devices.

[0006] In order to achieve the above object, the first aspect of the present invention provides a divalent platinum complex, wherein the divalent platinum complex has a structure shown in formula (I):

[0007]

[0008] Among them, R a is a substituted or unsubstituted alkyl group having 3 or more carbon atoms;

[0009] R b is a substituted or unsubstituted alkyl group;

[0010] R c , R d and R e are the same or different, and are each independently selected from a single atomic substituent or a polyatomic substituent; the single atomic substituent includes a hydrogen atom and its isotope atoms or a halogen atom; the polyatomic substituent includes a substituted or unsubstituted alkyl group, a substituted or unsubstituted 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 alkoxy group, an aryloxy group, an ester group, a silane group, a polymer group, and one or more of the above substituents containing isotope atoms.

[0011] The second aspect of the present invention provides a method for preparing a divalent platinum complex, wherein the preparation method comprises:

[0012] (1) mixing a first ligand represented by formula (a), hydrazine hydrate and methanol and reacting them to obtain an intermediate 1 represented by formula (b);

[0013]

[0014] wherein x is one or more of Br, I, Cl and OTf;

[0015] (2) subjecting the intermediate 1 and the second ligand represented by formula (c) to a cyclization reaction to obtain the intermediate 2 represented by formula (d):

[0016]

[0017] (3) subjecting the intermediate 2 and the third ligand represented by formula (e) to a coupling reaction to obtain the intermediate 2 represented by formula (f):

[0018]

[0019] (4) in the presence of a platinum salt, subjecting the intermediate 2 represented by formula (f) to a metal coordination cyclization reaction to obtain a divalent platinum complex represented by formula (I);

[0020]

[0021] Among them, in formula (a), formula (b), formula (c), formula (d), formula (e), formula (f) and formula (I), R a , R b , R c , R d and R e Same definition as above.

[0022] The third aspect of the present invention provides a divalent platinum complex prepared by the aforementioned preparation method.

[0023] A fourth aspect of the present invention provides a use of the aforementioned divalent platinum complex in an electroluminescent material and / or a photoluminescent material.

[0024] A fifth aspect of the present invention provides a use of the aforementioned divalent platinum complex in an organic optoelectronic device for lighting and / or display.

[0025] A sixth aspect of the present invention provides an organic photoelectric device, wherein the organic photoelectric device comprises a light-emitting layer, and the light-emitting layer comprises the aforementioned divalent platinum complex.

[0026] Through the above technical scheme, the divalent platinum complex provided by the present invention has the chemical structure described in formula (I), is a high-efficiency blue phosphorescent luminescent material, and can be used as an organic light-emitting diode device. The present invention generates a substituted pyrazole ligand by cyclization of a nitrile and a symmetrical diketone, and finally prepares a complex having a steric hindrance effect on the pyrazole structure. The ligand structure of the divalent platinum complex emits blue light with a peak between 450-465nm, has better luminous efficiency than molecules with low steric hindrance, and can therefore be used to prepare a high-efficiency organic light-emitting diode blue light device. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Luminescence spectrum of complex 1 prepared in Example 1 of the present invention in a thin film;

[0028] Figure 2 is a luminescence spectrum diagram of complex 2 prepared in Example 2 of the present invention in a thin film;

[0029] Figure 3 is the complex 1 prepared in Example 1 of the present invention 1 H NMR spectrum;

[0030] Figure 4 is the complex 2 prepared in Example 2 of the present invention 1 H NMR spectrum;

[0031] Figure 5 is the mass spectrum of complex 1 prepared in Example 1 of the present invention;

[0032] Figure 6 is the mass spectrum of complex 2 prepared in Example 2 of the present invention;

[0033] Figure 7 is the HPLC purity chart of complex 2 prepared in Example 2 of the present invention;

[0034] Figure 8 This is an electrochemical test diagram of complex 2 prepared in Example 2 of the present invention;

[0035] Fig. 9 is a cross-sectional view of an OLED device in a specific embodiment of the present invention;

[0036] Fig.10 is a schematic diagram of an OLED device according to a specific exemplary embodiment of the present invention;

[0037] Fig.11 is the luminescence spectrum of the blue light device using complex 1 in a specific embodiment of the present invention;

[0038] Fig.12It is a comparison chart of the photoelectric conversion current efficiency of the device using complex 1 of the present invention and Pt(pypzOczpy-3m) prepared in comparative example 1;

[0039] Fig.13 It is a comparison chart of the power efficiency of photoelectric conversion of complex 1 prepared in Example 1 of the present invention and Pt(pypzOczpy-3m) device prepared in Comparative Example 1. DETAILED DESCRIPTION

[0040] The endpoints and any values ​​of the ranges disclosed in this article 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 each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0041] As mentioned above, the first aspect of the present invention provides a divalent platinum complex, wherein the divalent platinum complex has a structure shown in formula (I):

[0042]

[0043] Among them, R a is a substituted or unsubstituted alkyl group having 3 or more carbon atoms;

[0044] R b is a substituted or unsubstituted alkyl group;

[0045] R c , R d and R e are the same or different, and are each independently selected from a single atomic substituent or a polyatomic substituent; the single atomic substituent includes a hydrogen atom and its isotope atoms or a halogen atom; the polyatomic substituent includes a substituted or unsubstituted alkyl group, a substituted or unsubstituted 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 alkoxy group, an aryloxy group, an ester group, a silane group, a polymer group, and one or more of the above substituents containing isotope atoms.

[0046] The inventors of the present invention have found that by introducing a pyrazole-linked pyridine substituted with a large sterically hindered alkyl group into a ligand of a divalent platinum complex, a new blue phosphorescent luminescent material is provided. In an embodiment of the present invention, the disclosed divalent platinum complex molecule coordinated by a neutral tetradentate ligand containing a pyrazole-linked pyridine structure can emit blue light as a phosphorescent luminescent material, and has good stability, high efficiency and is within the range of long-wavelength blue light, and is completely suitable as an organic blue light emitter in OLED-related products. In addition, the compounds provided by the embodiments of the present invention are easy to prepare and sublimate and purify, are soluble in general organic solvents, and can be suitable for device processes processed by evaporation and solution methods at the same time. The luminescent properties of this type of material have the characteristics of low energy and good color purity, which comprehensively surpasses various fluorescent materials in the prior art, and will change the situation of lack of stable and efficient blue light doping materials in the field of flat panel displays, while achieving the effect of emitting blue light color and improving device performance; the stable complex luminescent materials provided by the embodiments of the present invention have CIE coordinates and luminous efficiency that meet the requirements of flat panel displays.

[0047] According to the present invention, the substituted alkyl group is selected from one or more of an aryl-substituted alkyl group, a fluorine-substituted alkyl group and a halogenated alkyl group.

[0048] According to the present invention, the substituted aryl group is selected from an alkyl-substituted aryl group and / or an aryl-substituted aryl group.

[0049] According to the present invention, preferably, R b , R c , R d and R e Each of -CDH2, -CD2H, -CD3, -CDR1R2, and -CD2R1 is independently selected, wherein R1 and R2 are each independently selected from one or more of alkyl, substituted or unsubstituted aryl, alkyl-substituted aryl, aryl-substituted aryl, cycloalkyl, cycloalkenyl, heteroaryl, alkenyl, alkynyl, alkoxy, aryloxy, haloalkyl, ester, silane and polymer groups.

[0050] According to the present invention, R a C3-C 30 The alkyl group is preferably C3-C 11 of alkyl.

[0051] According to the present invention, R b , R c , R d and R e The alkyl groups in the groups are the same or different, and the alkyl groups are C1-C 30 The alkyl group is preferably C1-C 24 of alkyl.

[0052] According to the present invention, the isotope atoms are deuterium atoms and / or tritium atoms.

[0053] According to the present invention, the halogen atom is selected from one or more of a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

[0054] According to the present invention, preferably, R a Independently selected from but not limited to benzyl, diphenylmethyl, triphenylmethyl; 2-phenylethyl, 2,2-phenylethyl, 2-phenyl-2-propyl, propyl, isopropyl, 1,1,1,3,3,3-hexafluoro-2-propyl, butyl, isobutyl, hexafluoroisobutyl, tert-butyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, trimethylsilyl and triphenylsilyl;

[0055] According to the present invention, preferably, R b Independently selected from but not limited to 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; one or more of cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, trimethylsilyl and triphenylsilyl.

[0056] According to the present invention, preferably, R c , R d and R eeach independently selected from hydrogen, deuterium, fluorine atoms, 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 phenyl, 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, phenyl, 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-dicyclopropyl One or more of phenyl, 3,5-dicyclobutylphenyl, 3,5-dicyclopentylphenyl, 3,5-di-tert-butylphenyl, 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, 2,4,6-tricyclopentylphenyl, trimethylsilyl and triphenylsilyl.

[0057] According to the present invention, preferably, the divalent platinum complex is selected from at least one of the complexes 1-15 shown below:

[0058]

[0059]

[0060] According to the present invention, complexes 1-4 represent alkyl substituents R b It is a sterically hindered alkyl group.

[0061] The ligand structure of the present invention contains a pyrazole coordination structure with a large alkyl substituent. These two structures can inhibit the interaction between molecules and have better single-molecule blue light luminescence properties in a solid medium. This makes this type of new compound have a narrow blue phosphorescent emission spectrum, which will be able to promote the emission light color and improve the performance of blue phosphorescent devices.

[0062] The second aspect of the present invention provides a method for preparing a divalent platinum complex, wherein the preparation method comprises:

[0063] (1) mixing a first ligand represented by formula (a), hydrazine hydrate and methanol and reacting them to obtain an intermediate 1 represented by formula (b);

[0064]

[0065] wherein x is one or more of Br, I, Cl and OTf;

[0066] (2) subjecting the intermediate 1 and the second ligand represented by formula (c) to a cyclization reaction to obtain the intermediate 2 represented by formula (d):

[0067]

[0068] (3) subjecting the intermediate 2 and the third ligand represented by formula (e) to a coupling reaction to obtain the intermediate 2 represented by formula (f):

[0069]

[0070] (4) in the presence of a platinum salt, subjecting the intermediate 2 represented by formula (f) to a metal coordination cyclization reaction to obtain a divalent platinum complex represented by formula (I);

[0071]

[0072] Among them, in formula (a), formula (b), formula (c), formula (d), formula (e), formula (f) and formula (I), R a , R b , R c , R d and R e Same definition as above.

[0073] The present invention prepares a platinum complex blue phosphorescent material coordinated by a tetradentate ligand of 2-pyrazolylpyridyl through a new synthesis route. Through this synthesis method, large alkyl substituents can be introduced at both ends of the pyrazole of the ligand, and a more stable and efficient blue phosphorescent luminescence effect can be obtained.

[0074] According to the present invention, in step (1), the first ligand represented by the formula (a), hydrazine hydrate and methanol are added to a sealed tube, the obtained mixture is heated and stirred after nitrogen bubbling; cooled to room temperature, water is added to quench the reaction, extracted with ethyl acetate, the organic phases are combined, washed with an appropriate amount of saturated sodium chloride aqueous solution and then dried over anhydrous sodium sulfate; the solvent is distilled off under reduced pressure to obtain a crude white solid, i.e., the intermediate 1 represented by the formula (b); wherein, relative to 10-50 mL of methanol, the molar amount of the first ligand represented by the formula (a) is 2-8 mmol, and the molar amount of the hydrazine hydrate is 5-10 mmol.

[0075] According to the present invention, the reaction conditions include: temperature of 80-150° C. and time of 8-15 h.

[0076] According to the present invention, in step (2), the cyclization reaction further comprises carrying out the reaction in the presence of 1,4-dioxane; adding the intermediate 1 represented by formula (b), the second ligand represented by formula (c) and 1,4-dioxane into the sealed tube, heating and stirring the obtained mixture overnight after bubbling with nitrogen; cooling to room temperature, adding water to quench the reaction, extracting with ethyl acetate, combining the organic phases, washing with an appropriate amount of saturated sodium chloride aqueous solution and drying with anhydrous sodium sulfate; distilling under reduced pressure to remove the solvent, separating and purifying the obtained crude product by silica gel column chromatography, the eluent being petroleum ether: ethyl acetate = 25:1, to obtain a white solid, i.e., the intermediate 2 represented by formula (d).

[0077] According to the present invention, relative to 10-50 mL of 1,4-dioxane, the molar amount of the intermediate 1 is 2-8 mmol, and the molar amount of the second ligand represented by formula (c) is 1-8 mmol.

[0078] According to the present invention, the conditions of the cyclization reaction include: temperature of 80-150° C. and time of 8-30 h.

[0079] According to the present invention, in step (3), the coupling reaction further comprises carrying out the reaction in the presence of cuprous bromide, 2,2,6,6-tetramethylheptane-3,5-dione, cesium carbonate and N,N-dimethylformamide; adding the intermediate 2 represented by formula (d), the third ligand represented by formula (e), cuprous bromide, 2,2,6,6-tetramethylheptane-3,5-dione, cesium carbonate and N,N-dimethylformamide to the sealed tube, heating and stirring the obtained mixture overnight after bubbling with nitrogen; cooling to room temperature, adding water to quench the reaction, extracting with ethyl acetate, combining the organic phases, washing with an appropriate amount of saturated sodium chloride aqueous solution and drying with anhydrous sodium sulfate; distilling under reduced pressure to remove the solvent, separating and purifying the obtained crude product by silica gel column chromatography, the eluent being petroleum ether: ethyl acetate = 5:1, to obtain a white solid, i.e., the intermediate 2 represented by formula (f).

[0080] According to the present invention, relative to 10-50 mL of N,N-dimethylformamide, the molar amount of the intermediate 2 is 1-10 mmol, the molar amount of the third ligand shown in formula (e) is 1-10 mmol, the molar amount of cuprous bromide is 0.1-1 mmol, the molar amount of 2,2,6,6-tetramethylheptane-3,5-dione is 1-10 mmol, and the molar amount of cesium carbonate is 5-20 mmol.

[0081] According to the present invention, the conditions of the coupling reaction include: temperature of 100-150° C. and time of 12-48 h.

[0082] According to the present invention, in step (4), the metal coordination cyclization reaction also includes the presence of acetic acid; adding intermediate 2 shown in formula (f), potassium chloroplatinite and acetic acid to the sealed tube, bubbling the obtained mixture with nitrogen, stirring and heating; cooling to room temperature, adding water to quench the reaction, extracting with dichloromethane, combining the organic phases, washing with an appropriate amount of saturated sodium chloride aqueous solution and drying with anhydrous sodium sulfate. The solvent is removed by distillation under reduced pressure, and the obtained crude product is separated and purified by silica gel column chromatography, the eluent is dichloromethane: methanol = 400: 1, and a yellow solid complex is obtained.

[0083] According to the present invention, the platinum metal salt comprises potassium chloroplatinite.

[0084] According to the present invention, relative to 50-150 mL of acetic acid, the molar amount of the intermediate 2 represented by formula (f) is 0.5-3 mmol, and the molar amount of potassium chloroplatinite is 0.5-3 mmol.

[0085] According to the present invention, the conditions of the metal coordination cyclization reaction include: in a N2 atmosphere, first stirring at a temperature of 10-50°C for 12-36h; then heating to 100-150°C for 24-72h.

[0086] According to the present invention, preferably, the reaction formula of the provided complex is as follows:

[0087]

[0088] Among them, R a , R b , R c , R d and R e The definition of is the same as that of formula (I).

[0089] In terms of reaction path, compared with CN111943987A, the synthesis method has the advantages of being simple and efficient. The substituted pyrazole ligand is generated by the reaction of nitrile and symmetrical diketone, and finally a complex with a steric hindrance effect on the pyrazole structure is prepared, which cannot be synthesized by the reaction path of CN111943987A. The ligand structure of the divalent platinum complex emits blue light with a peak between 450-465nm, and has better luminous efficiency than low steric hindrance molecules, so it can be used to prepare high-efficiency organic light-emitting diode blue light devices.

[0090] The third aspect of the present invention provides a divalent platinum complex prepared by the aforementioned preparation method.

[0091] The blue light wavelength peak of the divalent platinum complex provided by the embodiment of the present invention is in the range of 450 to 470 nm.

[0092] A fourth aspect of the present invention provides a use of the aforementioned divalent platinum complex in an electroluminescent material and / or a photoluminescent material.

[0093] According to the present invention, the divalent platinum complex is a blue light emitting material or a phosphorescent light emitting material.

[0094] A fifth aspect of the present invention provides a use of the aforementioned divalent platinum complex in an organic optoelectronic device for lighting and / or display.

[0095] A sixth aspect of the present invention provides an organic photoelectric device, wherein the organic photoelectric device comprises a light-emitting layer, and the light-emitting layer comprises the aforementioned divalent platinum complex.

[0096] According to the present invention, the organic photoelectric device further comprises a substrate, an anode layer, a hole transport layer, an electron transport layer and a metal cathode layer, wherein at least one of the electron transport layer and the hole transport layer comprises the aforementioned divalent platinum complex.

[0097] According to the present invention, the divalent platinum complex is the light-emitting material, host material or guest material in the light-emitting layer.

[0098] The present invention will be described in detail below through examples.

[0099] In the following examples and comparative examples:

[0100] (1) Nuclear magnetic resonance spectroscopy analysis: in CDCl3 or DMSO-d6 solution, recorded by Varian liquid nuclear magnetic resonance instrument 1 HNMR (hydrogen nuclear magnetic resonance) and 13C NMR spectra were recorded at 300 MHz, 400 MHz or 500 MHz, and chemical shifts were based on residual protonated solvent. If CDCl3 was used as solvent, tetramethylsilane (δ = 0.00 ppm) was used as an internal reference. 1 H NMR (hydrogen nuclear magnetic resonance) spectrum; recorded using CDCl3 (δ = 77.00 ppm) as an internal reference 13 C NMR (carbon nuclear magnetic resonance) spectrum. If DMSO-d6 is used as solvent, residual H2O (δ=3.33 ppm) is used as an internal reference to record 1 H NMR (hydrogen nuclear magnetic resonance) spectrum; recorded using DMSO-d6 (δ = 39.52 ppm) as an internal reference 13 C NMR (carbon nuclear magnetic resonance) spectroscopy. The following abbreviations are used to explain 1 H NMR (hydrogen nuclear magnetic resonance) multiplicity: s = singlet, d = doublet, t = triplet, q = quadruplet, p = quintet, m = multitet, br = broad.

[0101] (2) Mass spectrometry analysis: Some compounds were tested by electrospray ionization mass spectrometry (ESI-MS) using a Waters Aquity Qda ultrahigh pressure liquid chromatography-mass spectrometry instrument, or by high-resolution mass spectrometry using a matrix-assisted ionization time-of-flight mass spectrometer (MALDI-TOF-MS).

[0102] (3) Material purification: The final product, the platinum complex, was separated by column chromatography and preparative HPLC, and then purified by ultra-high vacuum (10 -4 ~10 -5 Pa) sublimation purification equipment is used to perform sublimation purification to the purity requirement for device production.

[0103] (4) High performance liquid chromatography analysis: using methanol / water (1 / 9) as the mobile phase, the purity of the platinum complex sample was analyzed.

[0104] (5) Cyclic voltammetry curve test and energy level calculation: The test uses a three-electrode system, with a platinum column as the working electrode, a platinum wire as the counter electrode, and silver / silver chloride (Ag / AgCl) as the reference electrode. Under a nitrogen atmosphere, the sample was tested using N,N-dimethylformamide containing 0.1M tetrabutylammonium hexafluorophosphate as the solvent, ferrocene as the internal standard, and a scan rate of 100mV / s. According to formulas 5-1, 5-2 and the CV test results, the highest occupied orbital (HOMO) and lowest unoccupied orbital (LUMO) energy levels of the platinum complex molecule can be calculated. Since the measured potential of ferrocene relative to the reference electrode in DMF solution is not a fixed value, but has slight differences in different platinum complex solutions, we choose the ferrocene redox potential measured in the test for calculation.

[0105] HOMO=-[E ox -E Fc / Fc+ox +4.8]eV 5-1

[0106] LUMO=-[E red -E Fc / Fc+red +4.8]eV 5-2

[0107] Where: E ox 、E red are the oxidation peak onset potential and reduction peak onset potential of the sample, E Fc / Fc+ox 、E Fc / Fc+red are the onset potential of the oxidation peak and the reduction peak of ferrocene, respectively, and 4.8 is the vacuum energy level of ferrocene.

[0108] (6) UV-Vis absorption spectrum test: The absorption spectrum of the platinum complex in dichloromethane solution at room temperature was tested with a scanning range of 250 to 500 nm and an interval of 1 nm.

[0109] (7) Steady-state spectrum test: The room temperature dichloromethane solution spectrum of the platinum complex, the 77K 2-methyltetrahydrofuran luminescence spectrum / excitation spectrum, and the 5wt% doped polymethyl methacrylate (PMMA) film spectrum were tested. The dichloromethane solution spectrum was tested after the solvent was fully bubbling 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; the film sample was tested in a glove box or a vacuum chamber to reduce the quenching effect of oxygen on the luminescence of the complex. In addition, the photoluminescence quantum yield (PLQY) of the platinum complex solution and film was tested using an integrating sphere.

[0110] (8) Transient spectrum and phosphorescence lifetime test: The Fluorolog-3 full spectrum optical platform was used to perform time-resolved spectrum test and luminescence lifetime half-life test on the room temperature dichloromethane solution of the platinum complex, and lifetime test on the 5wt% doped PMMA film. All tests were carried out under nitrogen or vacuum conditions.

[0111] Example 1

[0112] Preparation of complex 1.

[0113] (1) Synthesis of 4-chloro-2-hydrazino-6-methylpyridine:

[0114]

[0115] 2,4-dichloro-6-methylpyridine (5 mmol), hydrazine hydrate (7.5 mmol) and methanol (25 mL) were added to a 75 mL sealed tube, and the obtained mixture was heated and stirred at 100° C. for 12 h after nitrogen bubbling; cooled to room temperature, water was added to quench the reaction, extracted with ethyl acetate, the organic phases were combined, washed with an appropriate amount of saturated sodium chloride aqueous solution, and dried over anhydrous sodium sulfate; the solvent was removed by distillation under reduced pressure to obtain a crude white solid 4-chloro-2-hydrazinyl-6-methylpyridine;

[0116] (2) Synthesis of 4-chloro-2-(3,5-isopropyl-1H-pyrazol-1-yl)-6-methylpyridine:

[0117]

[0118] 4-chloro-2-hydrazino-6-methylpyridine (5 mmol), 2,6-dimethylheptane-3,5-dione (5.5 mmol) and 1,4-dioxane (25 mL) were added to a 75 mL sealed tube, and the obtained mixture was heated and stirred at 110°C for 12 h after nitrogen bubbling; cooled to room temperature, water was added to quench the reaction, extracted with ethyl acetate, the organic phases were combined, washed with an appropriate amount of 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 separated and purified by silica gel column chromatography, the eluent was petroleum ether: ethyl acetate = 25:1, and a white solid 4-chloro-2-(3,5-diisopropyl-1H-pyrazol-1-yl)-6-methylpyridine was obtained;

[0119] (3) Synthesis of 2-(2-(3,5-diisopropyl-1H-pyrazol-1-yl)-6-methylpyridin-4-yl)oxy)-9-(pyridin-2-yl)-9H carbazole, ie, ligand L1:

[0120]

[0121] To a 25 mL sealed tube were added 4-chloro-2-(3,5-diisopropyl-1H-pyrazol-1-yl)-6-methylpyridine (5.5 mmol), 9-(pyridin-2-yl)-9H-carbazole-2-ol (5 mmol), cuprous bromide (0.5 mmol), 2,2,6,6-tetramethylheptane-3,5-dione (4 mmol), cesium carbonate (12.5 mmol) and N,N-dimethylformamide (25 mL). The resulting mixture was bubbled with nitrogen and heated at 120 °C. The mixture was heated and stirred at ℃ for 24 hours; cooled to room temperature, water was added to quench the reaction, extracted with ethyl acetate, the organic phases were combined, washed with an appropriate amount of saturated sodium chloride aqueous solution, and then dried over anhydrous sodium sulfate; the solvent was removed by distillation under reduced pressure, and the obtained crude product was separated and purified by silica gel column chromatography, the eluent was petroleum ether: ethyl acetate = 5:1, and a white solid 2-(2-(3,5-diisopropyl-1H-pyrazol-1-yl)-6-methylpyridin-4-yl)oxy)-9-(pyridin-2-yl)-9H-carbazole was obtained;

[0122] (4) Synthesis of Complex 1:

[0123]

[0124] Add ligand L1 (1 mmol), potassium chloroplatinate (1.1 mmol) and acetic acid (100 mL) to a 350 mL sealed tube, and the resulting mixture is bubbled with nitrogen, stirred at 30°C for 24 h, and then heated at 120°C for 48 h; cooled to room temperature, quenched with water, extracted with dichloromethane, combined organic phases, washed with an appropriate amount of saturated sodium chloride aqueous solution, and dried over anhydrous sodium sulfate. The solvent is removed by distillation under reduced pressure, and the resulting crude product is separated and purified by silica gel column chromatography, with the eluent being dichloromethane: methanol = 400: 1, to obtain a yellow solid complex 1.

[0125] Figure 3 The divalent platinum complex 1 of the present invention is shown. 1 H NMR spectrum: 1 H NMR(400MHz, DMSO-d6)δ9.18(d,J=6.0Hz,1H),8.25-8.12(m,4H),7.89(d,J=8.4Hz,1H),7.51-7.47(m,1H),7.43-7.40(m,1H),7.35-7 .30(m,1H),7.16-7.14(m,2H),6.76(s,1H),3.76-3.70(m,1H),3.20-3.14(m,1H),2.46(s,3H),1.42-1.36(m,8H),1.23-1.16(m,4H).

[0126] MS(ESI):694.20[M+H] +.

[0127] Example 2

[0128] Preparation of complex 2.

[0129] (1) The synthesis method of 4-chloro-2-hydrazino-6-methylpyridine is the same as that in Example 1.

[0130] (2) Synthesis of 4-chloro-2-(3,5-tert-butyl-1H-pyrazol-1-yl)-6-methylpyridine:

[0131]

[0132] 4-chloro-2-hydrazino-6-methylpyridine (5 mmol), 2,2,6,6-tetramethylheptane-3,5-dione (5.5 mmol) and 1,4-dioxane (25 mL) were added to a 75 mL sealed tube, and the obtained mixture was heated and stirred at 110°C for 12 h after nitrogen bubbling; cooled to room temperature, water was added to quench the reaction, extracted with ethyl acetate, the organic phases were combined, washed with an appropriate amount of 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 separated and purified by silica gel column chromatography, the eluent was petroleum ether: ethyl acetate = 15:1, and a white solid 4-chloro-2-(3,5-di-tert-butyl-1H-pyrazol-1-yl)-6-methylpyridine was obtained;

[0133] (3) Synthesis of 2-(2-(3,5-di-tert-butyl-1H-pyrazol-1-yl)-6-methylpyridin-4-yl)oxy)-9-(pyridin-2-yl)-9H carbazole, ie, ligand L2:

[0134]

[0135] To a 75 mL sealed tube were added 4-chloro-2-(3,5-di-tert-butyl-1H-pyrazol-1-yl)-6-methylpyridine (5.5 mmol), 9-(pyridin-2-yl)-9H-carbazole-2-ol (5 mmol), cuprous bromide (0.5 mmol), 2,2,6,6-tetramethylheptane-3,5-dione (4 mmol), cesium carbonate (12.5 mmol) and N,N-dimethylformamide (25 mL). The resulting mixture was bubbled with nitrogen and heated at 120 °C. The mixture was heated and stirred at ℃ for 24 hours; cooled to room temperature, water was added to quench the reaction, extracted with ethyl acetate, the organic phases were combined, washed with an appropriate amount of saturated sodium chloride aqueous solution, and then dried over anhydrous sodium sulfate; the solvent was removed by distillation under reduced pressure, and the obtained crude product was separated and purified by silica gel column chromatography, the eluent was petroleum ether: ethyl acetate = 5:1, and a white solid 2-(2-(3,5-di-tert-butyl-1H-pyrazol-1-yl)-6-methylpyridin-4-yl)oxy)-9-(pyridin-2-yl)-9H-carbazole was obtained;

[0136] (4) Synthesis of Complex 2:

[0137]

[0138] Add ligand L2 (1 mmol), potassium chloroplatinate (1.1 mmol) and acetic acid (100 mL) to a 350 mL sealed tube, and the resulting mixture is bubbling with nitrogen, stirred at 30 ° C for 24 h, and then heated at 120 ° C for 48 h; cooled to room temperature, quenched with water, extracted with dichloromethane, combined organic phases, washed with an appropriate amount of saturated sodium chloride aqueous solution, and dried over anhydrous sodium sulfate. The solvent is removed by distillation under reduced pressure, and the resulting crude product is separated and purified by silica gel column chromatography, the eluent is dichloromethane: methanol = 500: 1, and a yellow solid complex 2 is obtained.

[0139] Complex 2 1 H NMR spectrum: 1 H NMR(400MHz,DMSO-d6)δ8.9(s,1H),8.18-8.15(m,3H),8.08-8.06(m,1H),7.92-7.88(m,1H),7.50-7.33(m,3H),7.29(d,J=1.6H z,1H),7.15-7.12(m,1H),6.9(d,J=2.8Hz,1H),2.45(d,J=2.8Hz,3H),1.65(s,9H),1.37(d,J=2.8Hz,9H).MS(ESI):722.23[M+H] + .

[0140] Example 3

[0141] Preparation of complex 3.

[0142] (1) Synthesis of 4-chloro-2-hydrazino-6-isopropylpyridine:

[0143]

[0144] 2,4-dichloro-6-isopropylpyridine (5 mmol), hydrazine hydrate (7.5 mmol) and methanol (25 mL) were added to a 75 mL sealed tube, and the obtained mixture was heated and stirred at 100° C. for 12 h after nitrogen bubbling; cooled to room temperature, water was added to quench the reaction, extracted with ethyl acetate, the organic phases were combined, washed with an appropriate amount of saturated sodium chloride aqueous solution, and dried over anhydrous sodium sulfate; the solvent was distilled off under reduced pressure to obtain a crude white solid 4-chloro-2-hydrazinyl-6-isopropylpyridine;

[0145] (2) Synthesis of 4-chloro-2-(3,5-diisopropylpyrazol-1-yl)-6-isopropylpyridine:

[0146]

[0147] 4-chloro-2-hydrazino-6-isopropylpyridine (5 mmol), 2,6-dimethylheptane-3,5-dione (5.5 mmol) and 1,4-dioxane (25 mL) were added to a 75 mL sealed tube, and the obtained mixture was heated and stirred at 110°C for 12 h after nitrogen bubbling; cooled to room temperature, water was added to quench the reaction, extracted with ethyl acetate, the organic phases were combined, washed with an appropriate amount of 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 separated and purified by silica gel column chromatography, the eluent was petroleum ether: ethyl acetate = 15:1, and a white solid 4-chloro-2-(3,5-diisopropylpyrazol-1-yl)-6-isopropylpyridine was obtained;

[0148] (3) Synthesis of 2-(3,5-diisopropyl-1H-pyrazol-1-yl)-6-isopropylpyridin-4-yl)oxy-9-pyridine-2-carbazole, ie, ligand L3:

[0149]

[0150] To a 75 mL sealed tube were added 4-chloro-2-(3,5-diisopropylpyrazol-1-yl)-6-isopropylpyridine (5.5 mmol), 9-(pyridin-2-yl)-9H-carbazole-2-ol (5 mmol), cuprous bromide (0.5 mmol), 2,2,6,6-tetramethylheptane-3,5-dione (4 mmol), cesium carbonate (12.5 mmol) and N,N-dimethylformamide (25 mL), and the resulting mixture was purged with nitrogen. After bubbling, heat and stir for 12 hours; cool to room temperature, add water to quench the reaction, extract with ethyl acetate, combine the organic phases, wash with an appropriate amount of saturated sodium chloride aqueous solution, and then add anhydrous sodium sulfate to dry; distill under reduced pressure to remove the solvent, and separate and purify the obtained crude product by silica gel column chromatography, the eluent is petroleum ether: ethyl acetate = 5:1, and a white solid 2-(3,5-diisopropyl-1H-pyrazol-1-yl)-6-isopropylpyridin-4-yl)oxy-9-pyridine-2-carbazole is obtained;

[0151] (4) Synthesis of Complex 3:

[0152]

[0153] Add ligand L3 (1 mmol), potassium chloroplatinate (1.1 mmol) and acetic acid (100 mL) to a 350 mL sealed tube, and the resulting mixture is bubbled with nitrogen, stirred at 30 ° C for 24 h, and then heated at 120 ° C for 48 h; cooled to room temperature, quenched with water, extracted with dichloromethane, combined organic phases, washed with an appropriate amount of saturated sodium chloride aqueous solution, and dried over anhydrous sodium sulfate. The solvent is removed by distillation under reduced pressure, and the resulting crude product is separated and purified by silica gel column chromatography, with the eluent being dichloromethane: methanol = 400: 1, to obtain a yellow solid complex 3.

[0154] Complex 3 1 H NMR spectrum: 1 H NMR (400MHz, DMSO-d6) δ9.17(d,J=6.0Hz,1H),8.24-8.11(m,4H),7.88(d,J=8.4Hz,1H),7.50-7.46(m,1H),7.42-7.40(m,1H),7.34-7.30( m,1H),7.15-7.13(m,2H),6.75(s,1H),3.76-3.70(m,2H),3.20-3.14(m,1H),1.41-1.35(m,14H),1.22-1.15(m,4H).MS(ESI):722.23[M+H] + .

[0155] Example 4

[0156] Preparation of complex 4.

[0157] (1) The synthesis method of 4-chloro-2-hydrazino-6-methylpyridine is the same as that in Example 1.

[0158] (2) The synthesis method of 4-chloro-2-(3,5-tert-butyl-1H-pyrazol-1-yl)-6-methylpyridine is the same as that in Example 2.

[0159] (3) Synthesis of 9-(4-tert-butyl)pyridin-2-yl)-2-(2-(3,5-di-tert-butyl-1H-pyrazol-1-yl)-6-methylpyridin-4-yl)oxy)-9H-carbazole, i.e., ligand L4:

[0160]

[0161] To a 75 mL sealed tube were added 4-chloro-2-(3,5-di-tert-butyl-1H-pyrazol-1-yl)-6-methylpyridine (5.5 mmol), 9-tert-butylpyridin-2-yl-9H-carbazole-2-ol (5 mmol), cuprous bromide (0.5 mmol), 2,2,6,6-tetramethylheptane-3,5-dione (4 mmol), cesium carbonate (12.5 mmol) and N,N-dimethylformamide (25 mL). The resulting mixture was bubbled with nitrogen and heated at 12 The mixture was heated and stirred at 0°C for 24 hours; cooled to room temperature, water was added to quench the reaction, extracted with ethyl acetate, the organic phases were combined, washed with an appropriate amount of saturated sodium chloride aqueous solution, and then dried over anhydrous sodium sulfate; the solvent was removed by distillation under reduced pressure, and the obtained crude product was separated and purified by silica gel column chromatography, the eluent was petroleum ether: ethyl acetate = 5:1, and a white solid 2-(2-(3,5-di-tert-butyl-1H-pyrazol-1-yl)-6-methylpyridin-4-yl)oxy)-9-(pyridin-2-yl)-9H-carbazole was obtained;

[0162] (4) Synthesis of complex 4:

[0163]

[0164] Add ligand L4 (1 mmol), potassium chloroplatinate (1.1 mmol) and acetic acid (100 mL) to a 350 mL sealed tube, and the resulting mixture is bubbling with nitrogen, stirred at 30°C for 24 h, and then heated at 120°C for 48 h; cooled to room temperature, quenched with water, extracted with dichloromethane, combined organic phases, washed with an appropriate amount of saturated sodium chloride aqueous solution, and dried over anhydrous sodium sulfate. The solvent is removed by distillation under reduced pressure, and the resulting crude product is separated and purified by silica gel column chromatography, with the eluent being dichloromethane: methanol = 500: 1, to obtain a yellow solid complex 4.

[0165] Complex 2 1 H NMR spectrum: 1 H NMR(400MHz, DMSO-d6)δ8.8(s,1H),8.18-8.14(m,3H),8.08-8.05(m,1H),7.92-7.87(m,1H),7.50-7.32(m,3H),7.28(d,J=1.6Hz,1H), 7.15-7.11(m,1H),6.9(d,J=2.8Hz,1H),2.44(d,J=2.8Hz,3H),1.65(s,9H),1.55(s,9H),1.37(d,J=2.8Hz,9H).MS(ESI):778.30[M+H] + .

[0166] Comparative Example 1

[0167] The complex structure used in Comparative Example 1 is shown below:

[0168]

[0169] In addition, the preparation method of the complex of Comparative Example 1 includes:

[0170] Comparative Example Complex 1 was prepared.

[0171] (1) Synthesis of 4-chloro-2-(3,5-dimethyl-1H-pyrazol-1-yl)-6-methylpyridine:

[0172]

[0173] 2,4-dichloro-6-methylpyridine (5mmol), 3,5-dimethylpyrazole (6mmol), cuprous iodide (0.75mmol), LP proline (1mmol), potassium carbonate (10mmol) and dimethyl sulfoxide (25mL) were added to a 75mL sealed tube. The obtained mixture was heated and stirred at 120°C for 12h after nitrogen bubbling; cooled to room temperature, water was added to quench the reaction, extracted with ethyl acetate, the organic phases were combined, washed with an appropriate amount of 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 separated and purified by silica gel column chromatography, the eluent was petroleum ether: ethyl acetate = 25:1, and a white solid 4-chloro-2-(3,5-dimethyl-1H-pyrazol-1-yl)-6-methylpyridine was obtained;

[0174] (3) Synthesis of 2-(2-(3,5-dimethyl-1H-pyrazol-1-yl)-6-methylpyridin-4-yl)oxy)-9-(pyridin-2-yl)-9H carbazole, ie, comparative example ligand L1:

[0175]

[0176] 4-Chloro-2-(3,5-methyl-1H-pyrazol-1-yl)-6-methylpyridine (5.5 mmol), 9-(pyridin-2-yl)-9H-carbazole-2-ol (5 mmol), cuprous bromide (0.5 mmol), 2,2,6,6-tetramethylheptane-3,5-dione (4 mmol), cesium carbonate (12.5 mmol) and N,N-dimethylformamide (25 mL) were added to a 75 mL sealed tube, and the resulting mixture was bubbled with nitrogen and heated at 120 °C. The mixture was heated and stirred for 24 hours under the conditions; cooled to room temperature, water was added to quench the reaction, extracted with ethyl acetate, the organic phases were combined, washed with an appropriate amount of saturated sodium chloride aqueous solution, and then dried over anhydrous sodium sulfate; the solvent was removed by distillation under reduced pressure, and the obtained crude product was separated and purified by silica gel column chromatography, the eluent was petroleum ether: ethyl acetate = 5: 1, and a white solid 2-(2-(3,5-diisopropyl-1H-pyrazol-1-yl)-6-methylpyridin-4-yl)oxy)-9-(pyridin-2-yl)-9H-carbazole was obtained;

[0177] (4) Synthesis of Comparative Example Complex 1:

[0178]

[0179] Comparative example ligand L1 (1 mmol), potassium chloroplatinate (1.1 mmol) and acetic acid (100 mL) were added to a 350 mL sealed tube. The resulting mixture was stirred at 30 ° C for 24 h after nitrogen bubbling, and then heated at 120 ° C for 48 h; cooled to room temperature, water was added to quench the reaction, extracted with dichloromethane, and the organic phases were combined, washed with an appropriate amount of saturated sodium chloride aqueous solution, and then dried over anhydrous sodium sulfate. The solvent was removed by distillation under reduced pressure, and the resulting crude product was separated and purified by silica gel column chromatography, with the eluent being dichloromethane: methanol = 400: 1, to obtain a yellow solid complex 1.

[0180] The complex prepared in Comparative Example 1 1 H NMR spectrum: 1 H NMR (400MHz, DMSO-d6) δ9.24-9.22(m,1H),8.21-8.13(m,3H),8.09(d,J=8.4Hz,1H),7.87(d,J=8.4Hz,1H),7.50-7.46(m,1H),7 .42-7.38(m,1H),7.32-7.28(m,1H),7.16-7.13(m,2H),6.49(s,1H),2.77(s,3H),2.45(d,J=4.8Hz,6H).MS(ESI):638.14[M+H] + .

[0181] Test Example 1

[0182] Characterization of luminescence properties of the complex

[0183] Representative data of the color purity of the emitter can be obtained from the emission spectrum of a thin film prepared using a 5% PMMA (polymethyl methacrylate) dichloromethane solution. Table 1 shows the emission spectrum data of the above complex. In the following Table 1, λ is the peak wavelength, CIE (x, y) is the chromaticity coordinate parameter based on the International Commission on Illumination standard, and the display index (CRI index) adopts the internationally accepted measurement standard. The peak wavelengths of complexes 1, 2, 3, and 4 prepared in the embodiments of the present invention are between 450 and 460, which meets the requirements for the application of blue light. The half-peak width of the complex prepared in Comparative Example 1 is significantly wider, and the luminous efficiency is only 55%, and its overall luminous performance is poor.

[0184] Table 1

[0185]

[0186] in: a Dichloromethane solution, b PMMA film

[0187] like Figure 1 and Figure 2 The luminescence spectra of the divalent platinum complex in solution and film are shown; under 340nm ultraviolet light excitation, the luminescence wavelengths of the two complexes in dichloromethane solution and polymethyl methacrylate (PMMA) are between 450-500nm, and the wavelengths of the two complexes are both in the deep blue light region. This shows that this series of complexes are very good blue luminescent materials. Compared with the same core compound structure of CN 111943987 A, this type of complex with alkyl substitution on pyrazole has a higher energy level and a higher luminescence peak.

[0188] Figure 2 It shows that the emission peak of the emission spectrum of the divalent platinum complex 2 in the PMMA film is 452nm and the half-peak width is 54nm, which is a very good blue light emitting material.

[0189] Test Example 2

[0190] Characterization of band gap and related optical properties of the complex

[0191] The band gaps and related optical properties of the above divalent platinum complexes 1, 2, 3, and 4 are characterized as follows:

[0192] The band gap value of the material (E g), LUMO and HOMO values ​​were measured by cyclic voltammetry (CV). The entire test process was carried out on a CHI600D electrochemical workstation (Shanghai Chenhua Instrument Co., Ltd.) in a glove box (Lab2000, Etelux). A three-electrode system was formed with 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 process was a 0.1M tetrabutylammonium hexafluorophosphate (Bu4NPF6) dimethylformamide (DMF) solution, and the measured potentials were all based on the added ferrocene (Fc) as the internal standard. In the table below, λ is the peak wavelength of the divalent platinum complex dissolved in dichloromethane, FWHM is its half-peak width, and the triplet photon energy of the material (E T1 ) is calculated from the formula 1240 / λ 0-0 Calculated from (λ 0-0 is the first vibration peak under 77K conditions), and its unit is electron volt (eV).

[0193] Table 2 shows the energy level data of the above complexes. From the data in Table 2, it can be seen that the energy levels of the HOMO orbitals of complexes 1, 2, 3, and 4 are lower than those of the comparative complexes, indicating that large steric hindrance aromatic groups can reduce the HOMO energy level of the material. The triplet energy of the four divalent platinum complexes is 2.79-2.82 eV, which is mainly related to the parent core structure, indicating that under low temperature conditions, that is, when the molecular thermal motion is restricted, the triplet radiation transition is consistent. This also shows that these divalent platinum complexes can be regulated within a small range by introducing substituents to regulate their energy levels and emission spectra, thereby obtaining the optimal luminescence spectrum range. Figure 8 The cyclic voltammetry curve of the electrochemical analysis of complex 2 is shown. The oxidation / reduction half potential E obtained from the cyclic voltammetry test ox and E re The oxidation / reduction half potentials of reference ferrocene are 1.18 and -2.16 V, respectively. Fc / Fc+ is 0.63 / 0.52v, through formula E HOMO / LUMO =-[E ox / re,onset -E (Fc / Fc+) The values ​​of HOMO / LUMO of other examples measured by electrochemical method are shown in Table 2.

[0194] Table 2

[0195]

[0196]

[0197] Figure 3 , Figure 4 The above divalent platinum complexes 1 and 2 show 1The H NMR nuclear magnetic hydrogen spectrum shows that the compound can be successfully prepared and separated and purified by the method provided by the present invention. Therefore, this embodiment shows that the preparation process of this type of small molecule is effective and feasible in practical application.

[0198] Figure 5 , Figure 6 The mass spectrometry characterization diagrams of the above-mentioned divalent platinum complexes 1 and 2 are shown, indicating that we have successfully prepared this type of compound.

[0199] Figure 7 The HPLC purity chart of the above divalent platinum complex 2 is shown, indicating that this type of compound can be effectively separated and purified.

[0200] Figure 8 The electrochemical characterization diagram of the above-mentioned divalent platinum complex 2 is shown, and the diagram shows a reversible oxidation peak, indicating that the complex 2 has good stability under oxidative conditions.

[0201] Application Example 1

[0202] Application of divalent platinum complexes in blue light OLED devices

[0203] Fig. 9 A cross-sectional view of an OLED light-emitting device 1000 is shown, and the OLED device can use the divalent platinum complex described in this article as a 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 including an emitter and a host. Wherein EIL refers to an electron injection layer, which can be regarded as a part of the electron transport layer 1010. HIL is a hole injection layer, which can be regarded as a part of the hole transport layer 1006. CPL is a cathode cover layer. The complex 101 disclosed in this article is used in the light-emitting layer 1008 as a blue light-emitting doping material.

[0204] In the above specific embodiments, the light-emitting layer 1008 may include one or more divalent platinum complexes provided by the present invention, optionally with a host material. The ETL layer 1010 and the HTL 1006 may also include one or more divalent platinum complexes and another injection layer close to the electrode. The materials of the injection layer may include an EIL (electron injection layer), a HIL (hole injection layer) and a CPL (cathode cover layer), which may be in the form of 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 luminescent color of the OLED is determined by the luminescent energy (optical energy gap) of the light-emitting layer 1008 material, and the luminescent energy (optical energy gap) of the light-emitting layer 1008 material may be tuned by tuning the electronic structure of the emitting divalent platinum complex and / or the host material as described above. 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.

[0205] The complex of the present invention is doped into a host material as a light-emitting material to prepare an OLED device, and the device data are compared under parallel conditions. The structures of complexes 1 to 4 are superior to the structure of the comparative example complex in device performance.

[0206] OLED device structure can be Fig.10 On the basis of the charge blocking layer, such as the hole blocking layer HBL and the electron blocking layer EBL, the efficiency of the device is improved. Fig.10Device structure: 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 P-type and N-type materials respectively, and the materials can be organic materials or inorganic materials. BD refers to blue light doping material, that is, the platinum complex of the present invention. In addition, the complex of the present invention can also be used in the following common device structures: ITO / HATCN (10nm) / NPD (40nm) / TAPC (10nm) / 2,6-mCPy: divalent platinum complex / DPPS (40nm) / LiF / Al; ITO / HATCN (10nm) / NPD (40nm) / TAPC (10nm) / TAPC: PO15: divalent platinum complex (25nm) / PO15 (10nm) / BmPyPB / LiF / Al; ITO / HATCN (10nm) / NPD (40nm) / mCBP: divalent platinum complex / BAlq (10nm) / Alq (30nm) / LiF / Al; ITO / HATCN (10nm) / NPD (40nm) / TAPC (10nm) / host material: divalent platinum complex / DPPS (40nm) / BmPyPB or TmPyPB / LiF / Al; ITO / HATCN (10nm) / HTL / EBL / bipolar host material: divalent platinum complex / bipolar host material / BmPyPB or TmPyPB / LiF / Al; divalent platinum complex / DPPS (40nm) / BmPyPB or TmPyPB / LiF / Al; ITO / HATCN (10nm) / NPD (40nm) / TrisPCz (10nm) / mCBP: divalent platinum complex (25nm) / Balq (10nm) or mCBT (8nm) / BPyTP (40nm) / LiF / Al, etc. Fig.10 This is one of the schematic diagrams of the structure of an OLED containing EBL and HBL layers using the complex 1 of the present invention as an electroluminescent material. By adding a barrier layer, the charge utilization rate and luminous efficiency can be improved, and the stability of the device can also be increased.

[0207] Fig.11The luminescence spectrum of the device using platinum complex 1 is shown. The blue light with the structure of ITO / HATCN (10nm) / NPD (40nm) / TAPC (10nm) / 2,6-mCPy: 5% complex 2 (25nm) / 2,6-mCPy (10nm) / TmPyPB (30nm) / LiF (1nm) / Al (100nm) is used. According to the electroluminescence spectrum of the device with 5% complex doped in the light-emitting layer, the luminescence peak is red-shifted by 6nm relative to its photoluminescence peak in the PMMA medium, and the half-peak width is equivalent, maintaining the luminescence characteristics of the luminescent complex 2 itself. The chromaticity coordinate value calculated is CIE (0.14, 0.14), indicating that this device is suitable for use as a deep blue light emitting device. According to the normalized integral, the component of irritating blue light less than 450nm is only 2.3%. 97.7% of the photon energy is above 450nm. According to traditional blue light attribution, blue light photons between 450-500 nm account for 38.7% of the number of all emitted photons.

[0208] Comparative experiment on the photoelectric conversion current efficiency of devices prepared by complex 1 and comparative example complex materials

[0209] Fig.12 The photoelectric conversion current efficiency diagram of the device prepared using the complex 1 of the present invention and the complex of comparative example 1 is shown in FIG. Fig.12 It can be seen that the current efficiency of the device prepared using complex 1 is slightly higher than that of the comparative material Pt(pypzOczpy-3m). 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). Fig.12 The photoelectric conversion current efficiency of the device using complex 1 was very stable, from 0mA / cm 2 Up to 20mA / cm 2 Under the change of current density, the current roll-off is 22.6%, and the device of this doped material has a high efficiency, among which the 5% doped device has a high efficiency of 10mA / cm 2 The current efficiency is 8.4 cd / A, indicating that complex 1 has efficient and stable luminescent light conversion performance as a blue light emitting doping material.

[0210] Power efficiency of devices with complex 2 in photoelectric conversion

[0211] Fig.13The power efficiency of the photoelectric conversion of the device prepared by the comparative material Pt(pypzOczpy-3m) prepared by using complex 2 and comparative 1 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). Fig.13 From the comparison of the photoelectric conversion power efficiency of the device prepared with complex 2 and the comparative material Pt(pypzOczpy-3m), it can be seen that the device prepared with complex 2 has higher power efficiency, which means that complex 2 has efficient and stable luminescent photoconversion performance as a blue light emitting doping material.

[0212] Performance comparison experiment of light-emitting devices prepared using divalent platinum complexes

[0213] The performance data of the light-emitting device prepared using the above platinum complex is shown in Table 3 Device Light Emitting Performance.

[0214] Table 3

[0215]

[0216] As shown in Table 3, the luminescence performance data of the light-emitting devices prepared by various platinum complexes are compared. The electroluminescence wavelength of the light-emitting 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 light-emitting device is also consistent with the trend of the luminescence quantum efficiency of the divalent platinum complex itself, and the color purity of the light emitted by the light-emitting device is directly related to the spectral color purity of the light emitted under the light excitation of the doping material itself. It can be seen from the comparison of the electroluminescence spectrum of the divalent platinum complex light-emitting device and the photoluminescent device in the thin film that the electroluminescence spectrum of the light-emitting device is slightly red-shifted compared to the photoluminescence spectrum of the thin film, but the peak wavelength is still in the blue light region (460-470nm), and most of the spectrum is also in the blue light range. The calculated chromaticity coordinates show that the light-emitting device belongs to a pure blue light-emitting device. Since most of the light is in the blue light range, only a small amount of long-wavelength light needs to be filtered out, which means that the complex material provided by the embodiments of the present invention can fully meet the chromaticity requirements of high-efficiency pure blue light CIE (0.14, 0.08) of the top-emitting device in the display.

[0217] Combining the experimental process and results, complex 1-4 has the following characteristics compared with the control example: 1. Better solubility and stability, which can be speculated in principle to have advantages in the preparation of wet displays; 2. Complex 1-4 has better spectral stability and is more suitable for solving the bottleneck problem of current OLED blue phosphorescent materials and devices; 3. Experimental data show that complex 1-4 under 5% doping concentration conditions does not emit light from the excited complex, and a higher doping concentration can be used to make blue phosphorescent OLED display devices.

[0218] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A divalent platinum complex, characterized in that The divalent platinum complex has a structure shown in formula (I): Among them, R a is a substituted or unsubstituted alkyl group having 3 or more carbon atoms; R b is a substituted or unsubstituted alkyl group; R c , R d and R e are the same or different, and are each independently selected from a single atomic substituent or a polyatomic substituent; the single atomic substituent includes a hydrogen atom and its isotope atoms or a halogen atom; the polyatomic substituent includes a substituted or unsubstituted alkyl group, a substituted or unsubstituted 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 alkoxy group, an aryloxy group, an ester group, a silane group, a polymer group, and one or more of the above substituents containing isotope atoms.

2. The divalent platinum complex according to claim 1, wherein The substituted alkyl group is selected from one or more of an aryl-substituted alkyl group, a fluorine-substituted alkyl group and a haloalkyl group; And / or, the substituted aryl group is selected from an alkyl-substituted aryl group and / or an aryl-substituted aryl group.

3. The divalent platinum complex according to claim 1, wherein R b , R c , R d and R e Each of -CDH2, -CD2H, -CD3, -CDR1R2, and -CD2R1 is independently selected, wherein R1 and R2 are each independently selected from one or more of alkyl, substituted or unsubstituted aryl, alkyl-substituted aryl, aryl-substituted aryl, cycloalkyl, cycloalkenyl, heteroaryl, alkenyl, alkynyl, alkoxy, aryloxy, haloalkyl, ester, silane and polymer groups.

4. The divalent platinum complex according to any one of claims 1 to 3, wherein R a C3-C 30 The alkyl group is preferably C3-C 11 The alkyl group; and / or, R b , R c , R d and R e The alkyl groups in the groups are the same or different, and the alkyl groups are C1-C 30 The alkyl group is preferably C1-C 24 The alkyl group; and / or, the isotope atoms are selected from deuterium atoms and / or tritium atoms; And / or, the halogen atom is selected from one or more of a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

5. The divalent platinum complex according to any one of claims 1 to 4, wherein R a Independently selected from but not limited to benzyl, diphenylmethyl, triphenylmethyl; 2-phenylethyl, 2,2-phenylethyl, 2-phenyl-2-propyl, propyl, isopropyl, 1,1,1,3,3,3-hexafluoro-2-propyl, butyl, isobutyl, hexafluoroisobutyl, tert-butyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, trimethylsilyl and triphenylsilyl; and / or, R b Independently selected from but not limited to 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; one or more of cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, trimethylsilyl and triphenylsilyl; and / or, R c , R d and R e Each of the following is independently selected from hydrogen, deuterium, fluorine atoms, 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 phenyl, 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, phenyl, 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-dicyclopropyl One or more of phenyl, 3,5-dicyclobutylphenyl, 3,5-dicyclopentylphenyl, 3,5-di-tert-butylphenyl, 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, 2,4,6-tricyclopentylphenyl, trimethylsilyl and triphenylsilyl.

6. The divalent platinum complex according to any one of claims 1 to 5, wherein The divalent platinum complex is selected from at least one of the complexes 1-15 shown below:

7. A method for preparing a divalent platinum complex, characterized in that: The preparation method comprises: (1) mixing a first ligand represented by formula (a), hydrazine hydrate and methanol and reacting them to obtain an intermediate 1 represented by formula (b); wherein x is one or more of Br, I, Cl and OTf; (2) subjecting the intermediate 1 and the second ligand represented by formula (c) to a cyclization reaction to obtain the intermediate 2 represented by formula (d): (3) subjecting the intermediate 2 and the third ligand represented by formula (e) to a coupling reaction to obtain the intermediate 2 represented by formula (f): (4) in the presence of a platinum salt, subjecting the intermediate 2 represented by formula (f) to a metal coordination cyclization reaction to obtain a divalent platinum complex represented by formula (I); Among them, in formula (a), formula (b), formula (c), formula (d), formula (e), formula (f) and formula (I), R a , R b , R c , R d and R e Same as the definition in any one of claims 1 to 5.

8. The preparation method according to claim 7, wherein: In step (1), relative to 10-50 mL of methanol, the molar amount of the first ligand represented by formula (a) is 2-8 mmol, and the molar amount of hydrazine hydrate is 5-10 mmol; And / or, the reaction conditions include: temperature of 80-150° C. and time of 8-15 h.

9. The preparation method according to claim 7, wherein: In step (2), the cyclization reaction further comprises being carried out in the presence of 1,4-dioxane; and / or, relative to 10-50 mL of 1,4-dioxane, the molar amount of the intermediate 1 is 2-8 mmol, and the molar amount of the second ligand represented by formula (c) is 1-8 mmol; And / or, the conditions of the cyclization reaction include: temperature of 80-150° C. and time of 8-30 h.

10. The preparation method according to claim 7, wherein: In step (3), the coupling reaction further comprises carrying out in the presence of cuprous bromide, 2,2,6,6-tetramethylheptane-3,5-dione, cesium carbonate and N,N-dimethylformamide; and / or, relative to 10-50 mL of N,N-dimethylformamide, the molar amount of the intermediate 2 is 1-10 mmol, the molar amount of the third ligand represented by formula (e) is 1-10 mmol, the molar amount of cuprous bromide is 0.1-1 mmol, the molar amount of 2,2,6,6-tetramethylheptane-3,5-dione is 1-10 mmol, and the molar amount of cesium carbonate is 5-20 mmol; And / or, the conditions of the coupling reaction include: temperature of 100-150° C. and time of 12-48 h.

11. The preparation method according to claim 7, wherein: In step (4), the metal coordination cyclization reaction further comprises being carried out in the presence of acetic acid; And / or, the platinum metal salt comprises potassium chloroplatinite; and / or, relative to 50-150 mL of acetic acid, the molar amount of the intermediate 2 represented by formula (f) is 0.5-3 mmol, and the molar amount of potassium chloroplatinite is 0.5-3 mmol; And / or, the conditions of the metal coordination cyclization reaction include: in a N2 atmosphere, first stirring at a temperature of 10-50°C for 12-36 hours; then heating to 100-150°C for 24-72 hours.

12. A divalent platinum complex prepared by the preparation method according to any one of claims 7 to 11.

13. Use of the divalent platinum complex according to any one of claims 1 to 6 and 12 in electroluminescent materials and / or photoluminescent materials.

14. The use according to claim 13, wherein: The divalent platinum complex is used as a blue light emitting material and / or a phosphorescent light emitting material.

15. Use of the divalent platinum complex according to any one of claims 1 to 6 and 12 in an organic optoelectronic device for lighting and / or display.

16. An organic optoelectronic device, characterized in that: The organic optoelectronic device comprises a light-emitting layer, wherein the light-emitting layer comprises the divalent platinum complex according to any one of claims 1 to 6 and 12.

17. The organic optoelectronic device according to claim 16, wherein: The organic photoelectric device further comprises a substrate, an anode layer, a hole transport layer, an electron transport layer and a metal cathode layer, wherein at least one of the electron transport layer and the hole transport layer comprises the divalent platinum complex according to any one of claims 1 to 5 and 11.

18. The organic optoelectronic device according to claim 16 or 17, wherein: The divalent platinum complex is a light-emitting material, a host material or a guest material in the light-emitting layer.

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