Production and application of tetradentate platinum(II) coordination compound

Abstract

Tetradentate platinum(II) coordination compound, having the structure shown in the following formula: where R1-R 20 independently selected from the group consisting of hydrogen, deuterium, halogen, silyl with 1-30 carbon atoms, cyano, saturated alkyl with 1-30 carbon atoms, substituted or unsubstituted aryl with 5-30 carbon atoms and substituted or unsubstituted heteroaryl with 5-30 carbon atoms; and where R 21 selected from the group consisting of substituted or unsubstituted aryl with 5-30 C atoms, or substituted or unsubstituted heteroaryl with 5-30 C atoms, wherein the substitution is substitution by halogen, deuterium, C1-C20 alkyl, C1-C10 silyl, or cyano, and wherein the heteroatoms in the heteroaryl group are one or more of N, O and S.

Description

Technical area

[0001] The present invention relates to a novel organometallic material made of tetradentate platinum(II) coordination compound, in particular a phosphorescent dopant used in the light-emitting layer of the OLED luminescent device to emit the photons. State of the art

[0002] The organic light-emitting diode (OLED), also known as organic electric laser display and organic light-emitting semiconductor, was discovered in 1987 by Professor Ching W. Tang, a Chinese-American scientist, in Kodak's laboratory (Appl Phys. Lett. 1987, 51, 913). Compared with traditional LCD (liquid crystal display) technology, OLED display technology has advantages such as self-luminous properties, a wide viewing angle, a near-infinitely high contrast ratio, low power consumption, extremely high response speed, and potential for flexibility and foldability, among others. OLED display technology has attracted much attention and research. The development of new OLED materials has always been the focus and challenge of OLED technology research.

[0003] Compared to LEDs (Light-Emitting Diodes) based on inorganic materials, OLEDs based on organic materials have many irreplaceable superior properties.The main reasons are: (1) organic materials can be easily filmed on any substrate and can be fabricated into ultra-thin flat panel displays; (2) the organic molecular structure can be molecularly designed to control the luminescence properties of the material and is easy to modify and transform; (3) the fluorescence quantum efficiency of organic luminescent materials is high, reaching almost 100%; (4) inorganic material-based LEDs are point light sources, while organic material-based OLED panels can be used to fabricate a surface light source; (5) the driving voltage of organic electroluminescent OLED devices is relatively low, while the driving voltage of inorganic LEDs is generally higher.

[0004] Among current OLED materials, transition metal-based phosphorescent materials are mainly used as doping layers of the light-emitting layer for photon emission. Among them, materials based on iridium(III) and platinum(II) coordination compounds have been widely studied. Generally, the metal coordination compound formed by the bidentate ligand and trivalent iridium has an octahedral coordination structure, with the iridium atom located at the center of the octahedron to chelate and coordinate with the bidentate ligand. The octahedral coordination structure of the iridium(III) coordination compound imparts strong three-dimensionality to the molecules and avoids stacking of the coordination compound molecules. In the fabrication of OLED devices, it is difficult to form excimer luminescence under high-concentration doping.However, with some asymmetric bidentate ligands, the iridium(III) coordination compound can produce isomers, and due to the different coordination orientations of the ligands, there are two types of structures - facet type and meridional type, which leads to difficulty in the deposition of the iridium(III) coordination compound and decrease the yield of the target iridium(III) coordination compound.

[0005] With the continuous breakthrough of phosphorescent materials made from iridium(III) coordination compounds, platinum(II)-based phosphorescent OLED materials have been gradually developed in recent years, achieving good research results. Unlike ordinary iridium(III), which forms an octahedral coordination structure, platinum(II) is quadruple coordinated, generally forming a coordination compound with a planar structure. Common ligands are mainly divided into bidentate, tridentate, and tetradentate ligands. Compared with bidentate or tridentate ligands, platinum(II) coordination compounds with a tetradentate ligand have the following advantages: 1) the platinum(II) coordination compound can be synthesized by a one-step reaction of the ligand, making the platinum(II) coordination compound easy to prepare and purify; 2) no isomers are produced during the synthesis of the platinum(II) coordination compound and the structure is specific; 3) Chelate coordination, stable structure; 4) there is a relatively good phosphorescence emission efficiency.

[0006] The platinum(II) coordination compound with a tetradentate ligand has attracted more research and attention due to its unique properties, in particular, the research group of Academician Zhiming Zhi from the University of Hong Kong has studied such coordination compounds in detail and achieved excellent results (Chem. Sci 2016, 7, 1653).

[0007] The platinum(II) coordination compound with a tetradentate ligand shows good performance, at the same time, due to the characteristics of the planar structure of the platinum(II) coordination compounds, it also leads to easy stacking between molecules and easy formation of excimers, etc., which degrades the performance of OLED device.

[0008] Further generic coordination compounds are disclosed in US 2019 / 0100 546 A1 and US 2019 / 0074454 A1. Content of the invention

[0009] The present application provides a novel Pt(II) coordination compound based on tetradentate ligands that emits green light and is used in OLED devices as a green phosphorescent OLED material. This new type of Pt(II) coordination compound has an ONCN chelate coordination model and a spiral ring structure on the molecular backbone, which greatly improves the three-dimensionality of the molecule, promotes the weakening of intermolecular interactions, avoids molecular stacking of the coordination compounds, suppresses the formation of excimers, and improves the efficiency and lifetime of OLED devices.

[0010] The novel organometallic material of tetradentate platinum(II) coordination compound according to the present invention has the structure shown in the following formula:wherein R1-R 20are independently selected from the group consisting of hydrogen, deuterium, halogen, cyano, silyl having 1-30 C atoms, saturated alkyl having 1-30 C atoms, substituted or unsubstituted aryl having 5-30 C atoms, and substituted or unsubstituted heteroaryl having 5-30 C atoms; and wherein R 21 is selected from the group consisting of substituted or unsubstituted aryl having 5-30 C atoms, or substituted or unsubstituted heteroaryl having 5-30 C atoms, wherein the substitution is substitution by halogen, C1-C20 alkyl, or cyano, and wherein the heteroatoms in the heteroaryl group are one or more of N, O and S.

[0011] Preferred are R1-R 20independently selected from the group consisting of hydrogen, halogen, cyano, saturated alkyl having 1-10 C atoms, aryl having 5-20 C atoms which is substituted or unsubstituted by halogen or one or more C1-C4 alkyl, heteroaryl having 5-20 C atoms which is substituted or unsubstituted by halogen or one or more C1-C4 alkyl, and R 21 selected from the group consisting of aryl having 5-20 C atoms which is substituted or unsubstituted by halogen or one or more C1-C4 alkyl, or heteroaryl having 5-20 C atoms which is substituted or unsubstituted by halogen or one or more C1-C4 alkyl, wherein the halogen is F, Cl or Br.

[0012] Preferred are 1-3 groups among the 21 groups from R1-R 21independently represented as aryl having 5-10 C atoms which is substituted or unsubstituted by halogen or 1-3 C1-C4 alkyl, N-containing heteroaryl having 5-10 C atoms which is substituted or unsubstituted by halogen or 1-3 C1-C4 alkyl; wherein other groups are independently represented as hydrogen or saturated alkyl having 1-8 C atoms, wherein the halogen is F or Cl.

[0013] Preferred are 1-3 groups among the 21 groups from R1-R 21 independently represented as phenyl, pyridyl and carbazolyl, and where other groups are independently represented as hydrogen, fluorine or saturated alkyl with 1-4 C atoms.

[0014] In one embodiment, the coordination compound has the structure shown in the following formula:

[0015] Wherein R1' is hydrogen, halogen or a saturated alkyl having 1-10 C atoms, R2'-R6' are independently selected from the group consisting of hydrogen, halogen, saturated alkyl having 1-10 C atoms, aryl having 5-20 C atoms which is substituted or unsubstituted by halogen or one or more C1-C4 alkyl, heteroaryl having 5-20 C atoms which is substituted or unsubstituted by halogen or one or more C1-C4 alkyl, wherein the halogen is F, Cl or Br, and wherein the heteroatom in the heteroaryl group is any of N, O and S.

[0016] Preferably, 0-3 groups among the 6 groups of R1'-R6' are independently represented as aryl having 5-10 C atoms, which is substituted or unsubstituted by halogen or 1-3 C1-C4 alkyl, heteroaryl having 5-10 C atoms, which is substituted or unsubstituted by halogen or 1-3 C1-C4 alkyl; with other groups independently represented as hydrogen, halogen or saturated alkyl having 1-8 C atoms, wherein the halogen is F or Cl.

[0017] Preferably, 0-3 groups among the 6 groups of R1'-R6' are independently represented as phenyl substituted or unsubstituted by C1-C4 alkyl, pyridyl or carbazolyl, and wherein other groups are independently represented as hydrogen, fluorine or saturated alkyl having 1-4 C atoms.

[0018] The precursor of the above-mentioned coordination compound is as shown in the following formula:

[0019] For the purposes of this application, the terms halogen, alkyl, alkenyl, aryl, acyl, alkoxy and heterocyclic aromatic systems or heterocyclic aromatic groups, unless otherwise stated, may have the following meanings: the above halogen or halo includes fluorine, chlorine, bromine and iodine, preferably F, Cl, Br, more preferably F or Cl, most preferably F.

[0020] The above-mentioned alkyl includes alkyl having 1-30 carbon atoms, preferably 1-10 carbon atoms, and more preferably 1-4 carbon atoms. The alkyl may be branched, straight-chain, or cyclic and may be interrupted by one or more heteroatoms, preferably N, O, or S. Furthermore, the alkyl may be substituted, for example, by one or more halogens. The alkyl is particularly preferably selected from a group consisting of methyl, ethyl, isopropyl, n-propyl, isobutyl, n-butyl, tert-butyl, sec-butyl, isopentyl, cyclopropyl, cyclopentyl, and cyclohexyl.

[0021] The above-mentioned heteroaryl groups should be understood as being related to aromatic series and C3-C8 ring groups and containing one oxygen or sulfur atom or 1-4 nitrogen atoms or a combination of one oxygen or sulfur atom and up to two nitrogen atoms, as well as their substituted and benzo- and pyrido-fused derivatives.

[0022] In certain embodiments, a heteroaryl may be a heterocyclic system bearing the above independent five- or six-membered aromatic series with 0, 1 or 2 substituents. Typical examples of heteroaryl include, but are not limited to: unsubstituted furans, benzofuran, thiophene, benzothiophene, pyrrole, pyridine, indole, azole, benzoxazole, isoxazole, benzisoxazole, thiazole, benzothiazole, isothiazole, imidazole, benzimidazole, pyrazole, indazole, tetrazole, quinoline, isoquinoline, pyridazine, pyrimidine, purine and pyrazine, furan, 1,2,3-oxadiazole, 1,2,3-thiadiazole, 1,2,4-thiadiazole, triazole, benzotriazole, pteridine, benzoxazole, diazole, benzopyrazole, quinazine, cinnoline, phthalazine, quinazoles and quinoxalines and their mono- or disubstituted derivatives. In certain embodiments, the substituents are halogen, hydroxy, cyano, OC 1-6 -Alkyl, C 1-6 -Alkyl, Hydroxy-C 1-6 -Alkyl and amino-C 1-6-Alkyl.

[0023] Specific examples are shown below, including but not limited to the following structures:

[0024] An application of the above coordination compound in the organic OLED luminescent devices.

[0025] Using platinum(II) coordination compounds with the above structures, thermally deposited and solution-processed OLED devices can be fabricated.

[0026] An organic luminescent device containing one or more of the above-mentioned coordination compounds.

[0027] The coordination compound is deposited in the form of a layer in the device by thermal deposition.

[0028] The coordination compound is applied in the form of a layer in the device by spin coating.

[0029] The coordination compound is applied in the form of a layer in the device by inkjet printing.

[0030] The above organic luminescent device emits orange-red light when a current is applied.

[0031] The organic metal coordination compound in the present invention has high fluorescence quantum efficiency, good thermal stability and low quenching constant, and can fabricate orange-red light OLED devices with high luminous efficiency and low waste. Short description of the drawing Fig. 1 shows a schematic structural view of the organic electroluminescent device of the present invention. Detailed embodiments

[0032] The present invention is explained in more detail below in connection with exemplary embodiments.

[0033] A process for preparing the above coordination compound, comprising the following steps: As shown below, the initial substrates S1 and S2 are subjected to a Suzuki-Miyaura coupling reaction to obtain a substrate S3, S3 and S4 are subjected to a Buchwald-Hartwig coupling reaction to obtain a substrate S5, and S5 and S6 are subjected to a Buchwald-Hartwig coupling reaction to obtain a substrate S7, and S7 is demethylated by high-temperature heating under the action of pyridine hydrochloride to obtain S8, and S8 is chelated with K2PtCl4 to obtain the target platinum(II) coordination compound TM.

[0034] The initial substrates, intermediates, solvents, and other reagents involved in the synthesis of the compounds in the present invention can be obtained from suppliers known to those skilled in the art, such as Energy Chemical, J&K, and Aladdin. Example 1

[0035] Synthesizing Compound 3: Take 20.0 g (0.10 mol) of Compound 1, 19.8 g (0.125 mol) of Compound 2, 3.46 g (0.03 eq., 3.0 mmol) of tetrakis(triphenylphosphine)palladium, 27.6 g (2.0 eq., 0.20 mol) of potassium carbonate and add them to a flask, 210 ml of dioxane and 60 ml of water are added, and the mixture is heated under nitrogen protection and reacted under reflux for 8 hours. After completion of the reaction, the mixture was cooled to room temperature, the solvent was removed by rotary evaporation, an appropriate amount of water and ethyl acetate was added for extraction, the organic phase was collected and dried, after removal of the solvent by rotary evaporation, a flash silica gel column (n-hexane / liquid phase ethyl acetate = 10:1) was used for separation, then the mixture was recrystallized to obtain 20.0 g of the target product compound 3 with a yield of 85% and a purity of 99.9%.

[0036] Synthesizing Compound 5: Take 11.7 g (50 mmol) of Compound 3, 9.3 g (50 mmol) of Compound 4, 450 mg (0.04 eq., 2 mmol) of palladium acetate, 0.40 g (0.08 eq., 4 mmol) of tri-tert-butylphosphine, 11.22 g (2.0 eq., 0.10 mol) of potassium tert-butoxide and add them to a flask, 200 ml of toluene is added, and the mixture is heated under nitrogen protection and reacted under reflux for 8 hours.After completion of the reaction, the mixture was cooled to room temperature, the solvent was removed by rotary evaporation, an appropriate amount of water and ethyl acetate was added for extraction, the organic phase was collected and dried, after removal of the solvent by rotary evaporation, a flash silica gel column (n-hexane / liquid phase ethyl acetate = 15:1) was used for separation, then the mixture was recrystallized to obtain 23.83 g of the target product compound 5 with a yield of 88% and a purity of 99.9%.

[0037] Synthesizing compound 7: Take 4.9 g (20 mmol) of compound 5, 7.9 g (20 mmol) of compound 6, 225 mg (0.02 eq., 1 mmol) of palladium acetate, 0.20 g (0.04 eq., 2 mmol) of tri-tert-butylphosphine, 4.5 g (2.0 eq., 0.04 mol) of potassium tert-butoxide and add them to a flask, 100 ml of toluene is added, and the mixture is heated under nitrogen protection and reacted under reflux for 8 hours. After completion of the reaction, the mixture was cooled to room temperature, the solvent was removed by rotary evaporation, an appropriate amount of water and ethyl acetate was added for extraction, the organic phase was collected and dried, after removal of the solvent by rotary evaporation, a flash silica gel column (n-hexane / liquid phase ethyl acetate = 10:1) was used for separation, then the mixture was recrystallized to obtain 8.9 g of the target product compound 7 with a yield of 75% and a purity of 99.9%.

[0038] Synthesize Compound 8: Take 5.9 g (10 mmol) of Compound 7 and 50 g of pyridine hydrochloride, heat under nitrogen protection at 200°C, and react for 8 hours. After the reaction, an appropriate amount of water and ethyl acetate were added for extraction. The organic phase was collected and dried. After removing the solvent by rotary evaporation, a flash silica gel column (n-hexane / liquid phase ethyl acetate = 15:1) was used for separation. Then, the mixture was recrystallized with methanol to obtain 5.0 g of the target product Compound 8 in 86% yield and 99.9% purity. Mass spectrum (ESI-) ([MH]-) C41H27N3O, theoretical value: 576.22, actual value: 576.21.

[0039] Synthesize compound Pt-1: Take 1.15 g (2.0 mmol) of compound 8, 160 mg (0.25 eq., 0.5 mmol) of tetrabutylammonium bromide, and 930 mg (1.2 eq., 2.4 mmol) of potassium tetrachloroplatinate and dissolve them in 50 mL of acetic acid, vacuum, introduce nitrogen and replace it with nitrogen several times, stir, and heat to 130°C and react for 12 hours.After the reaction, the solvent was removed by cooling and rotary evaporation. Then, an appropriate amount of water and ethyl acetate were added for extraction. The organic phase was collected. The mixture was dried over anhydrous magnesium sulfate, and the solvent was removed by rotary evaporation. A flash silica gel column (n-hexane / dichloromethane liquid phase = 10:1) was used for separation. Afterward, the mixture was recrystallized with methanol. The crude product was subjected to vacuum sublimation to obtain 616 mg of red solid with an overall yield of 40% and a purity of 99.95%. Mass spectrum (ESI-) ([M+H]-) C41H25N3OPt, theoretical value: 771.16, actual value: 771.19. Example 2

[0040] The preparation method of Pt-2 is the same as the synthesis route of Pt-1, the only difference being that compound 9 is used instead of compound 4. The molecular formula of compound 9 is shown below: Example 3

[0041] The preparation method of Pt-3 is the same as the synthesis route of Pt-1, the only difference being that compound 9 is used instead of compound 4 and compound 10 is used instead of compound 6. The molecular formula of compound 10 is shown below:

[0042] The preparation method of Pt-12 is the same as the synthesis route of Pt-1, the only difference being that compound 11 is used instead of compound 2, compound 12 is used instead of compound 4, and compound 10 is used instead of compound 6. The molecular formula of compound 11 is shown below:

[0043] Below are application examples of the compounds of the present invention: ITO / TAPC (70nm) / TCTA:Pt(II) (40nm) / TmPyPb (30nm) / LiF (1nm) / Al (90nm) Manufacturing process of the device:

[0044] The transparent anodized indium tin oxide (ITO) (10 Ω / sq) glass substrate is ultrasonically cleaned using acetone, ethanol, and distilled water sequentially and then treated with oxygen plasma for 5 min.

[0045] The ITO substrate is then mounted on the substrate holder of a vacuum gas phase evaporation device. In the evaporation device, the system pressure is set to 10 -6 Torr regulated.

[0046] The hole transfer layer (HTL) material TAPC is then evaporated onto the ITO substrate with a thickness of 70 nm.

[0047] Subsequently, the material of the light-emitting layer (EML)TCTA is evaporated with a thickness of 40 nm, which is doped with the platinum(II) coordination compound with a mass fraction of 10%.

[0048] The electron transfer layer (ETL) material TmPyPb is then evaporated to a thickness of 30 nm.

[0049] Then, LiF is evaporated to a thickness of 1 nm to form the electron injection layer (EIL).

[0050] Finally, Al is evaporated to a thickness of 90 nm as a cathode to complete the encapsulation of the device. As shown in Fig. 1 shown.

[0051] Device STD, Device 1, Device 2, Device 3, and Device 4 are fabricated sequentially. The structure and fabrication process of the devices are exactly the same. The difference is that the platinum(II) coordination compounds STD, Pt-1, Pt-2, Pt-3, and Pt-12 are used sequentially as dopants in the light-emitting layer. The reference material STD is a classic green light material with an ONCN coordination structure.

[0052] The device comparison results are shown in Table 1 and are based on the performance of the STD device; - means that the data is flat, - means that the relative benchmark performance deteriorates by more than 5%, + means that the relative benchmark performance improves by 5%, and ++ means that the relative benchmark performance improves by 10%. Device 1 Device 2 Device 3 Device 1 Maximum external quantum efficiency + + ++ ++ External quantum efficiency at 100nit + + + ++ Starting voltage - - - - Power efficiency at 100nit + + + ++

[0053] As shown in the table above, the performance of the organic electroluminescent device fabricated based on the platinum(II) coordination compound of the present invention exhibits varying degrees of performance improvement compared to the reference device. This new type of Pt(II) coordination compound has strong molecular three-dimensionality and weak intermolecular interaction, which prevents the stacking of the coordination compound molecules and greatly inhibits the formation of excimers, thus improving the efficiency of OLED devices. In summary, the performance of the organic electroluminescent device fabricated by the present invention exhibits greater performance improvement compared to the reference device, and the novel tetradentate platinum(II) coordination compound metal-organic material concerned has great application value.

Claims

[1] Tetradentate platinum(II) coordination compound having the structure shown in the following formula: where R1-R 20 are independently selected from the group consisting of hydrogen, deuterium, halogen, silyl having 1-30 C atoms, cyano, saturated alkyl having 1-30 C atoms, substituted or unsubstituted aryl having 5-30 C atoms and substituted or unsubstituted heteroaryl having 5-30 C atoms; and where R 21 is selected from the group consisting of substituted or unsubstituted aryl having 5-30 C atoms, or substituted or unsubstituted heteroaryl having 5-30 C atoms, wherein the substitution is substitution by halogen, deuterium, C1-C20 alkyl, C1-C10 silyl, or cyano, and wherein the heteroatoms in the heteroaryl group are one or more of N, O and S. [2] A coordination compound according to claim 1, wherein R1-R 20are independently selected from the group consisting of hydrogen, halogen, cyano, saturated alkyl having 1-10 C atoms, aryl having 5-20 C atoms which is substituted or unsubstituted by halogen or one or more C1-C4 alkyl, heteroaryl having 5-20 C atoms which is substituted or unsubstituted by halogen or one or more C1-C4 alkyl, and R 21 selected from the group consisting of aryl having 5-20 C atoms which is substituted or unsubstituted by halogen or one or more C1-C4 alkyl, or heteroaryl having 5-20 C atoms which is substituted or unsubstituted by halogen or one or more C1-C4 alkyl, wherein the halogen is F, Cl or Br. [3] A coordination compound according to claim 2, wherein 1-3 groups among the 21 groups of R1-R 21are independently represented as aryl having 5-10 C atoms, which is substituted or unsubstituted by halogen or 1-3 C1-C4 alkyl, N-containing heteroaryl having 5-10 C atoms, which is substituted or unsubstituted by halogen or 1-3 C1-C4 alkyl; and wherein other groups are independently represented as hydrogen or saturated alkyl having 1-8 C atoms, and wherein the halogen is F or Cl. [4] A coordination compound according to claim 3, wherein 1-3 groups among the 21 groups of R1-R 21 are independently represented as phenyl, pyridyl and carbazolyl, and other groups are independently represented as hydrogen, fluorine or saturated alkyl having 1-4 C atoms. [5] A coordination compound according to claim 1, having the structure represented by the following formula: wherein R1' is hydrogen, halogen, or saturated alkyl having 1-10 C atoms, R2'-R6' are independently selected from the group consisting of hydrogen, halogen, saturated alkyl having 1-10 C atoms, aryl having 5-20 C atoms which is substituted or unsubstituted by halogen or one or more C1-C4 alkyl, heteroaryl having 5-20 C atoms which is substituted or unsubstituted by halogen or one or more C1-C4 alkyl, and wherein the halogen is F, Cl or Br, and wherein the heteroatom in the heteroaryl group is any of N, O and S. [6] A coordination compound according to claim 5, wherein 0-3 groups among the 6 groups of R1'-R6' are independently represented as aryl having 5-10 C atoms which is substituted or unsubstituted by halogen or 1-3 C1-C4 alkyl, heteroaryl having 5-10 C atoms which is substituted or unsubstituted by halogen or 1-3 C1-C4 alkyl; and wherein other groups are independently represented as hydrogen, halogen or saturated alkyl having 1-8 C atoms, wherein the halogen is F or Cl. [7] A coordination compound according to claim 6, wherein 0-3 groups among the 6 groups of R1'-R6' are independently represented as phenyl substituted or unsubstituted by C1-C4 alkyl, pyridyl or carbazolyl, and wherein other groups are independently represented as hydrogen, fluorine or saturated alkyl having 1-4 C atoms. [8] A coordination compound according to claim 1, having the structure shown below: [9] Precursor of the coordination compound according to any one of claims 1 to 8, namely ligand having a structural formula shown below:wherein R1-R 21 as defined in claim 1. [10] A synthesis process for the tetradentate platinum coordination compound according to claim 5, comprising the following steps: the initial substrates S1 and S2 are subjected to a Suzuki-Miyaura coupling reaction to obtain a substrate S3, wherein S3 and S4 are subjected to a Buchwald-Hartwig coupling reaction to obtain a substrate S5, and wherein S5 and S6 are subjected to a Buchwald-Hartwig coupling reaction to obtain a substrate S7, and wherein S7 is demethylated by high-temperature heating under the action of pyridine hydrochloride to obtain S8, and wherein S8 is chelated with K2PtCl4 to obtain the target platinum(II) coordination compound TM, [11] Use of the coordination compound according to any one of claims 1 to 8 in the OLED luminescent device. [12] Use according to claim 9, wherein the coordination compound according to any one of claims 1 to 8 is a phosphorescent dopant used in the light-emitting layer to emit the photons.

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