Divalent metal complexes, methods of making and using the same, and organic optoelectronic devices

Abstract

The present application relates to the technical field of photoelectric material, specifically, to divalent metal complexes such as divalent platinum complexes and preparation method and application thereof and organic photoelectric devices containing the complexes. The divalent metal complexes have the structure shown in formula (I). The green light wavelength peak of the divalent metal complexes is 515-535 nm, CIE very good coverage green light interval, and has higher current efficiency and energy efficiency.

Description

Technical Field

[0001] This invention relates to the field of optoelectronic materials technology, specifically to divalent metal complexes, such as divalent platinum complexes, their preparation methods and applications, and organic optoelectronic devices comprising said complexes. Background Technology

[0002] In modern society, the development of optoelectronic materials occupies an increasingly important position, especially in the field of materials for optical or electroluminescent devices, where much research has been conducted. Organometallic complexes can emit light of different colors when energized, showing great promise in flat panel displays and solid-state lighting applications. Products based on molecular-level semiconductor technologies, represented by organic light-emitting diodes (OLEDs), offer numerous advantages in terms of applicability and low energy consumption.

[0003] In terms of light emission, green is one of the three primary colors of RGB. Currently, the main optoelectronic materials applicable to light-emitting and lighting devices are red and green phosphorescent organometallic materials and blue fluorescent organometallic materials. These materials have achieved great success in lighting and advanced display applications, but they still suffer from drawbacks such as short luminous lifespan, high heat generation, and low actual efficiency in large-size display devices. In addition to basic red, green, and blue primary color devices, there is also an urgent need for white light devices. White light is a combination of visible light, and high-efficiency and high-stability white phosphorescent light sources can be formed by the combination of blue, green, and red phosphorescence.

[0004] Therefore, high-efficiency green phosphorescent materials and devices have practical application value in organic optoelectronic devices, especially in display devices and / or lighting devices. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing OLED technology in terms of the insufficient luminescence color, efficiency, and stability of green phosphorescent complex materials. It provides divalent metal complexes, preferably divalent platinum complexes, their preparation methods and applications, as well as organic optoelectronic devices incorporating them. Light-emitting devices prepared using the green phosphorescent divalent metal complexes provided by this invention, such as divalent platinum complexes, exhibit green light wavelength peaks in the 530-540 nm range, and the CIE (Chemical Ion Emission Model) covers the green light range very well. Furthermore, they possess high current efficiency and energy efficiency, better meeting the requirements of flat panel displays.

[0006] To achieve the above objectives, a first aspect of the present invention provides a divalent metal complex having the structure shown in formula (I):

[0007]

[0008] In equation (I):

[0009] M is either Pt or Pd, preferably Pt;

[0010] A can be O or S, preferably O;

[0011] R1 is a trimethylsilyl group, optionally substituted C1-C. 30 Alkyl, optionally substituted C3-C 12 cycloalkyl, optionally substituted C5-C 30 Aryl, optionally substituted C2-C 30 Heteroaryl, optionally substituted C1-C 30 Alkoxy, optional substituted C3-C 12 Cycloalkyloxy, optionally substituted C5-C 30 aryloxy groups, optionally substituted C5-C 30 Aromatic amino groups, optionally substituted C5-C 30 Heteroaryl groups or optionally substituted C5-C 30 heteroaryl amino groups; and

[0012] R2-R 17 The atoms, whether identical or different, are independently selected from hydrogen atoms, hydrogen isotopes, halogen atoms, cyano groups, isocyano groups, thiocyano groups, isothiocyano groups, trimethylsilyl groups, or optionally substituted C1-C atoms. 30 Alkyl, optionally substituted C3-C 12 cycloalkyl, optionally substituted C5-C 30 Aryl, optionally substituted C2-C 30 Heteroaryl, optionally substituted C1-C 30 Alkoxy, optional substituted C3-C 12 Cycloalkyloxy, optionally substituted C5-C 30 aryloxy groups, optionally substituted C5-C 30 Aromatic amino groups, optionally substituted C5-C 30 Heteroaryl groups and optionally substituted C5-C 30 heteroaryl amino groups;

[0013] "Optionally substituted" means that the group may or may not be further substituted by one or more groups selected from C1-C1. 30 Alkyl, C3-C 12 cycloalkyl, C1-C 30 Alkoxy, C5-C 30 Aryl, C2-C 30 heteroaryl, C5-C 30 The substitution of aryloxy groups and halogen groups.

[0014] In some embodiments, the divalent metal complex is a divalent platinum complex with the structure shown in formula (I'):

[0015]

[0016] In equation (I'):

[0017] R1 is a trimethylsilyl group, optionally substituted C1-C. 30 Alkyl, optionally substituted C3-C 12 cycloalkyl, optionally substituted C5-C 30 Aryl, optionally substituted C2-C 30 Heteroaryl, optionally substituted C1-C 30 Alkoxy, optional substituted C3-C 12 Cycloalkyloxy, optionally substituted C5-C 30 aryloxy groups, optionally substituted C5-C 30 Aromatic amino groups, optionally substituted C5-C 30 Heteroaryl groups or optionally substituted C5-C 30 heteroaryl amino groups; and

[0018] R2-R 17 The atoms, whether identical or different, are independently selected from hydrogen atoms, hydrogen isotopes, halogen atoms, cyano groups, isocyano groups, thiocyano groups, isothiocyano groups, trimethylsilyl groups, or optionally substituted C1-C atoms. 30 Alkyl, optionally substituted C3-C 12 cycloalkyl, optionally substituted C5-C 30 Aryl, optionally substituted C2-C 30 Heteroaryl, optionally substituted C1-C 30 Alkoxy, optional substituted C3-C 12 Cycloalkyloxy, optionally substituted C5-C 30 aryloxy groups, optionally substituted C5-C 30 Aromatic amino groups, optionally substituted C5-C 30 Heteroaryl groups and optionally substituted C5-C 30 heteroaryl amino groups;

[0019] "Optionally substituted" means that the group may or may not be further substituted by one or more groups selected from C1-C1. 30 Alkyl, C3-C 12 cycloalkyl, C1-C 30 Alkoxy, C5-C 30 Aryl, C2-C 30 heteroaryl, C5-C 30 The substitution of aryloxy groups and halogen groups.

[0020] A second aspect of the present invention provides a method for preparing the above-described divalent metal complexes, the method comprising:

[0021] (1) Compound a shown in formula (a) is subjected to a first coupling reaction with phenol compound b shown in formula (b) to obtain compound c shown in formula (c);

[0022]

[0023] (2) The compound c shown in formula (c) is subjected to a functional group transformation reaction to obtain the compound shown in formula (d);

[0024]

[0025] (3) The compound d shown in formula (d) is subjected to a second coupling reaction with the compound h shown in formula (h) to obtain the compound shown in formula (e), and the compound e shown in formula (e) is subjected to a third coupling reaction with the amine compound i shown in formula (i) to obtain the compound f shown in formula (f); or, (4) The compound d shown in formula (d) is subjected to a third coupling reaction with the o-aniline compound j shown in formula (j) to obtain the compound f shown in formula (f);

[0026]

[0027] (5) The compound f shown in formula (f) is subjected to a ring-closure reaction to obtain the compound g shown in formula (g); preferably, the compound f shown in formula (f) is subjected to a ring-closure reaction with ammonium hexafluorophosphonate and triethyl orthoformate to obtain the compound g shown in formula (g);

[0028]

[0029] (6) In the presence of a divalent platinum or palladium compound, compound g of formula (g) is subjected to a cyclometalation reaction to obtain a divalent metal complex of formula (I);

[0030] Among them, the groups R1-R in formulas (I), (a), (b), (c), (d), (e), (f), (g), (h), (i), and (j) 17 The definition of A is the same as that described in the first aspect above;

[0031] In equations (a), (c), (e), (h), and (j), X may be the same or different, and may be F, Br, I, Cl, or OTf, respectively.

[0032] Preferably, the method of the present invention is a method for preparing divalent platinum complexes of formula (I'), the method comprising:

[0033] (1) Under a protective atmosphere, furan compound a shown in formula (a) and phenol compound b with a substituent shown in formula (b) are subjected to a first coupling reaction to obtain compound c shown in formula (c);

[0034] (2) Under a protective gas, compound c shown in formula (c) is subjected to a functional group transformation reaction, wherein the X group is changed to an amino group to obtain the compound shown in formula (d).

[0035] (3) Under a protective atmosphere, compound d of formula (d) is coupled with compound h of formula (h) which has a substituent to undergo a second coupling reaction to obtain compound (e); and compound e of formula (e) is coupled with amine compound i of formula R1-NH2 to undergo a third coupling reaction to obtain compound f of formula (f); or, (4) Under a protective atmosphere, compound d of formula (d) is coupled with o-aniline compound j of formula (j) to obtain compound f of formula (f);

[0036] (5) Under a protective atmosphere, compound f, as shown in formula (f), is reacted with ammonium hexafluorophosphonate and triethyl orthoformate to undergo a cyclization reaction to obtain compound f, as shown in formula (g).

[0037] (6) In the presence of cyclooctadienyl dichloride platinum(II) or dichloride platinum, compound g of formula (g) is subjected to a cyclometalation reaction to obtain the divalent platinum complex of formula (I');

[0038]

[0039] The definitions of the groups in formulas (I'), (a), (b), (c), (d), (e), (f), (g), (h), and (j) are the same as those described in the first aspect above;

[0040] X in equations (a), (c), (e), (h), and (j) may be the same or different, and may be F, Br, I, Cl, or OTf, respectively.

[0041] A third aspect of the present invention provides the application of the aforementioned divalent metal complexes, such as divalent platinum complexes, in organic optoelectronic devices, such as organic electroluminescent devices.

[0042] The fourth aspect of the present invention provides an application of the aforementioned divalent metal complexes, such as divalent platinum complexes, in green phosphorescent organic optoelectronic devices.

[0043] A fifth aspect of the present invention provides an organic optoelectronic device, preferably an organic electroluminescent device, comprising an anode layer, a light-emitting layer, and a cathode layer, wherein the light-emitting layer comprises the divalent metal complex described above, preferably a divalent platinum complex. In some embodiments, the device comprises a substrate, an anode layer, a hole transport layer, a light-emitting layer, an electron transport layer, and a metal cathode layer, wherein at least one of the light-emitting layer, the electron transport layer, and the hole transport layer comprises the aforementioned divalent metal complex, such as a divalent platinum complex.

[0044] The divalent metal complexes, such as divalent platinum complexes, provided by this invention can be used as electroluminescent or photoluminescent materials; for example, they can be used as green light-emitting or phosphorescent materials. Furthermore, the divalent metal complexes, such as divalent platinum complexes, provided by this invention can be used to prepare light-emitting devices with a green light wavelength peak in the 530-540 nm range and a spectrum mostly within the green light range; calculated chromaticity coordinates indicate that the light-emitting device is a green light-emitting device, covering the green light range very well; the highest current efficiency (CE) of the light-emitting device can reach 63.70 cd / A and the highest energy efficiency (PE) can reach 81.30 lm / W. In addition, the full width at half maximum (FWHM) of the green light spectrum obtained from the divalent metal complexes, such as divalent platinum complexes, provided by this invention can be less than 30 nm, and the photoluminescence quantum yield can be greater than 95%. Attached Figure Description

[0045] Figure 1 This is the emission spectrum of complex 2 prepared in Example 1 of the present invention in solution and thin film;

[0046] Figure 2 This is the emission spectrum of complex 4 prepared in Example 2 of the present invention in solution and thin film;

[0047] Figure 3 This is the emission spectrum of complex 16 prepared in Example 3 of the present invention in solution and thin film;

[0048] Figure 4 This is the UV-Vis absorption spectrum of complex 2 prepared in Example 1 of this invention;

[0049] Figure 5 It is the complex 2 prepared in Example 1 of this invention. 1 H NMR spectrum;

[0050] Figure 6 It is the complex 4 prepared in Example 2 of this invention. 1 H NMR spectrum;

[0051] Figure 7It is the complex 16 prepared in Example 3 of this invention. 1 H NMR spectrum;

[0052] Figure 8 This is a purity characterization diagram of complex 25 prepared in Example 4 of the present invention;

[0053] Figure 9 This is the mass spectrum of complex 25 prepared in Example 4 of the present invention;

[0054] Figure 10 This is the mass spectrum of complex 16 prepared in Example 3 of the present invention;

[0055] Figure 11 The diagram shows the structure of an OLED light-emitting device;

[0056] Figure 12 The emission spectrum of the device using complex 4 is shown;

[0057] Figure 13 This is the EQE-current density curve of the OLED device prepared by complex 4;

[0058] Figure 14 The graph shows the decay of electroluminescence over time in the device prepared by complex 4; and

[0059] Figure 15 A schematic diagram of the synthesis process of green phosphorescent divalent platinum complexes. Detailed Implementation

[0060] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0061] It is generally believed that the human eye can perceive green light with wavelengths between 500-560 nm. However, there are higher chromaticity standards for the green light required for displays. Currently, two standards are widely accepted: one is the CIE coordinate system (0.21, 0.71) for green light defined by the National Television Systems Committee (NTSC), and the other is the BT2020 standard proposed by the International Telecommunication Union (ITU) in 2016, with CIE coordinate requirements of (0.170, 0.797). The latter has higher chromaticity requirements than the former, thus placing higher demands on the monochromaticity of the light source. Monochromatic light with emission wavelengths within the 520-535 nm range better meets the chromaticity requirements of the BT2020 standard. In other words, the synthesized complexes need to have emission peaks in the 520-535 nm range and a narrow spectrum to better meet the chromaticity requirements of the BT2020 standard, and the better the monochromaticity of the material, the better it can be used in displays.

[0062] This invention provides a luminescent material that meets the above requirements.

[0063] As previously stated, the present invention provides a divalent metal complex, characterized in that the divalent metal complex has the structure shown in formula (I):

[0064]

[0065] In equation (I):

[0066] M is either Pt or Pd, preferably Pt;

[0067] A can be O or S, preferably O;

[0068] R1 is a trimethylsilyl group, optionally substituted C1-C. 30 Alkyl, optionally substituted C3-C 12 cycloalkyl, optionally substituted C5-C 30 Aryl, optionally substituted C2-C 30 Heteroaryl, optionally substituted C1-C 30 Alkoxy, optional substituted C3-C 12 Cycloalkyloxy, optionally substituted C5-C 30 aryloxy groups, optionally substituted C5-C 30 Aromatic amino groups, optionally substituted C5-C 30 Heteroaryl groups or optionally substituted C5-C 30 heteroaryl amino groups; and

[0069] R2-R 17 The atoms, whether identical or different, are independently selected from hydrogen atoms, hydrogen isotopes, halogen atoms, cyano groups, isocyano groups, thiocyano groups, isothiocyano groups, trimethylsilyl groups, or optionally substituted C1-C atoms. 30Alkyl, optionally substituted C3-C 12 cycloalkyl, optionally substituted C5-C 30 Aryl, optionally substituted C2-C 30 Heteroaryl, optionally substituted C1-C 30 Alkoxy, optional substituted C3-C 12 Cycloalkyloxy, optionally substituted C5-C 30 aryloxy groups, optionally substituted C5-C 30 Aromatic amino groups, optionally substituted C5-C 30 Heteroaryl groups and optionally substituted C5-C 30 heteroaryl amino groups;

[0070] "Optionally substituted" means that the group may or may not be further substituted by one or more groups selected from C1-C1. 30 Alkyl, C3-C 12 cycloalkyl, C1-C 30 Alkoxy, C5-C 30 Aryl, C2-C 30 heteroaryl, C5-C 30 The substitution of aryloxy groups and halogen groups.

[0071] In a preferred embodiment, M is Pt and A is O in formula (I). In this case, the present invention provides a divalent platinum complex having the structure shown in formula (I'):

[0072]

[0073] In equation (I'):

[0074] R1-R 17 Each is as defined in equation (I) above.

[0075] The inventors have unexpectedly discovered that the divalent platinum or palladium complex molecules containing neutral tetradentate ligands with dibenzofuran or dibenzothiophene structures disclosed in this application can emit green light as phosphorescent materials, and have the characteristics of good stability, high efficiency and narrow emission range, making them particularly suitable as organic green light emitters in OLED-related products.

[0076] Furthermore, the divalent metal complexes provided by this invention are easy to prepare and purify by sublimation, soluble in common organic solvents, and suitable for vapor deposition and solution-based device fabrication processes. These complexes exhibit excellent color purity, which will address the lack of stable, efficient narrow-band green phosphorescent materials in the flat panel display field, while simultaneously achieving the effect of emitting green light and improving device performance.

[0077] The CIE coordinates and luminous efficiency of the stable complex luminescent materials provided by this invention indicate that they are more suitable for the needs of flat panel displays.

[0078] In some implementations, in formula (I) or formula (I') above, R1 is an optionally substituted C1-C 12 Alkyl, optionally substituted C3-C8 cycloalkyl, optionally substituted C5-C 30 Aryl, optionally substituted C2-C 30 Heteroaryl, optionally substituted C1-C 12 Alkoxy, optional substituted C5-C 30 aryloxy or optionally substituted C5-C 30 Aromatic amino groups; and R2-R 17 Whether identical or different, each is independently selected from hydrogen atoms, hydrogen isotopes, halogen atoms, cyano groups, isocyano groups, thiocyano groups, isothiocyano groups, or optionally substituted C1-C atoms. 12 Alkyl, optionally substituted C3-C8 cycloalkyl, optionally substituted C5-C 30 Aryl, optionally substituted C2-C 30 Heteroaryl, optionally substituted C1-C 12 Alkoxy, optional substituted C5-C 30 aryloxy groups and optionally substituted C5-C 30 Aromatic amine group; wherein "optionally substituted" means that the group may or may not be further substituted by one or more groups selected from C1-C2. 12 Alkyl, C3-C8 cycloalkyl, C1-C 12 Alkoxy, C5-C 30 Aryl, C2-C 30 heteroaryl, C5-C 30 The substitution of aryloxy groups and halogen groups.

[0079] In some implementations, in formula (I) or formula (I') above, R1 is an optionally substituted C1-C 10 Alkyl, optionally substituted C3-C7 cycloalkyl, optionally substituted C5-C 24 Aryl or optionally substituted C2-C 24 heteroaryl; R2-R 17 Whether identical or different, each is independently selected from hydrogen atoms, hydrogen isotopes, halogen atoms, cyano groups, or optionally substituted C1-C atoms. 10 Alkyl, optionally substituted C3-C7 cycloalkyl, optionally substituted C5-C 24 Aryl and optionally substituted C2-C 24 Heteroaryl; where "optionally substituted" means that the group may or may not be further substituted by one or more groups selected from C1-C2. 10 Alkyl, C3-C7 cycloalkyl, C1-C10 Alkoxy, C5-C 24 Aryl, C2-C 24 heteroaryl and C5-C 24 Aryloxy groups and halogen groups are substituted.

[0080] In some embodiments, in formula (I) or formula (I') above, R1 is an optionally substituted C1-C6 alkyl, optionally substituted C3-C6 cycloalkyl, or optionally substituted C5-C6 cycloalkyl. 14 Aryl or optionally substituted C2-C 14 heteroaryl; R2-R 17 The atoms, whether identical or different, are independently selected from hydrogen atoms, hydrogen isotopes, halogen atoms, cyano groups, optionally substituted C1-C6 alkyl groups, optionally substituted C3-C6 cycloalkyl groups, and optionally substituted C5-C6 cycloalkyl groups. 14 Aryl and optionally substituted C2-C 14 Heteroaryl; wherein "optionally substituted" means that the group may or may not be further substituted by one or more groups selected from C1-C6 alkyl, C3-C6 cycloalkyl, C5-C6 alkyl, C6-C6 cycloalkyl, C6-C6 ... 14 Aryl, C2-C 14 Substitution of heteroaryl and halogen groups. The C1-C6 alkyl groups may be selected from or include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl (including all isomers), and hexyl (including all isomers). The C3-C6 cycloalkyl groups may be selected from or include cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl. The C5-C... 14 The aryl group may be selected from or include phenyl, naphthyl, fluorenyl, anthraceneyl, and biphenyl. The C2-C... 14 The heteroaryl group may be selected from or include furanyl, imidazolyl, isothiazolyl, isoxazolyl, oxadiazolyl, oxadiazolyl, oxazolyl, pyrazinyl, pyrazolyl, pyridinyl, pyrimidinyl, pyrroleyl, thiadiazolyl, thiazolyl, thiophenyl, triazinyl, and triazolyl.

[0081] In some embodiments, in formula (I) or formula (I') above, R1 is an optionally substituted C1-C4 alkyl, optionally substituted C5-C6 cycloalkyl, optionally substituted C6-C 14 Aryl or optionally substituted C3-C 14 heteroaryl; R2-R 17 The atoms, whether identical or different, are independently selected from hydrogen atoms, hydrogen isotopes, halogen atoms, cyano groups, optionally substituted C1-C4 alkyl groups, optionally substituted C5-C6 cycloalkyl groups, and optionally substituted C6-C4 cycloalkyl groups. 14 Aryl and optionally substituted C3-C 14Heteroaryl; wherein "optionally substituted" means that the group may or may not be further substituted by one or more groups selected from C1-C4 alkyl, C5-C6 cycloalkyl, C6-C 14 Aryl, C3-C 14 Substitution of heteroaryl and halogen groups. The C1-C4 alkyl group may be selected from or include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and tert-butyl. The C5-C6 cycloalkyl group may be selected from or include cyclopentyl and cyclohexyl. The C6-C... 14 The aryl group may be selected from or include phenyl, naphthyl, fluorenyl, anthraceneyl, and biphenyl. The C3-C... 14 The heteroaryl group may be selected from or include furanyl, imidazolyl, isothiazolyl, isoxazolyl, oxazolyl, pyrazinyl, pyrazolyl, pyridinyl, pyridinyl, pyrimidinyl, pyrroleyl, thiazolyl, thiophenyl, and triazinyl.

[0082] In some implementations, in formula (I) or formula (I') above, R1 is a polyatomic substituent; and R2-R 17 Each of the following is independently selected from hydrogen atoms, hydrogen isotopes, halogen atoms, cyano groups, isocyano groups, thiocyano groups, isothiocyano groups, and polyatomic substituents; the polyatomic substituents include C1-C... 12 Alkyl, C5-C 30 Aromatic groups, C1-C 12 The alkoxy group or the above-mentioned substituents containing isotopic atoms; the alkyl group includes unsubstituted straight-chain alkyl, substituted straight-chain alkyl, unsubstituted cycloalkyl, or substituted cycloalkyl; the aromatic group includes unsubstituted aryl, substituted aryl, aryloxy, arylamine, or heteroaryl. According to the present invention, preferably, the polyatomic substituent includes C1-C1 substituents. 10 Alkyl or C5-C 24 Aromatic group. According to the present invention, preferably, the alkyl group includes aryl-substituted alkyl, trimethylsilyl, unsubstituted cycloalkyl, or substituted cycloalkyl. According to the present invention, preferably, the aromatic group may include alkyl-substituted aryl or aryl-substituted aryl.

[0083] In some embodiments, in formula (I) or formula (I') above, R1 is selected from methyl, trideuterated methyl, benzyl, diphenylmethyl, triphenylmethyl, ethyl, 2-phenylethyl, 2,2-diphenylethyl, 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, pentadeuterated phenyl, 2-methylphenyl, 2 - Isopropylphenyl, 2-ethylphenyl, 4-methylphenyl, 4-isopropylphenyl, 4-ethylphenyl, 4-tert-butylphenyl, 2,3-dimethylphenyl, 2,3-diethylphenyl, 2,3-diisopropylphenyl, 2,3-diisobutylphenyl, 2,3-dicyclohexylphenyl, 2,3-dicyclopropylphenyl, 2,3-dicyclobutylphenyl, 2,3-dicyclopentylphenyl, 2,4-dimethylphenyl, 2,4-diethylphenyl, 2,4-diisopropylphenyl, 2,4-diisobutylphenyl, 2,4-di Cyclohexylphenyl, 2,4-dicyclopropylphenyl, 2,4-dicyclobutylphenyl, 2,4-dicyclopentylphenyl, 2,6-dimethylphenyl, 2,6-diethylphenyl, 2,6-diisopropylphenyl, 2,6-diisobutylphenyl, 2,6-dicyclohexylphenyl, 2,6-dicyclopropylphenyl, 2,6-dicyclobutylphenyl, 2,6-dicyclopentylphenyl, 3,5-dimethylphenyl, 3,5-diethylphenyl, 3,5-diisopropylphenyl, 3,5-diisobutylphenyl, 3,5-dicyclohexylphenyl 2,3,5-dicyclopropylphenyl, 3,5-dicyclobutylphenyl, 3,5-dicyclopentylphenyl, 2,3,5,6-tetramethylphenyl, 2,4,6-trimethylphenyl, 2,4,6-triethylphenyl, 2,4,6-triisopropylphenyl, 2,4,6-triisobutylphenyl, 2,4,6-tricyclohexylphenyl, 2,4,6-tricyclopropylphenyl, 2,4,6-tricyclobutylphenyl, 2,4,6-tricyclopentylphenyl, biphenyl-2-yl and 4'-tert-butylbiphenyl-2-yl; and R2-R 17The atoms, whether identical or different, are independently selected from hydrogen, deuterium, halogen atoms, methyl, trideuterated methyl, benzyl, diphenylmethyl, triphenylmethyl, ethyl, 2-phenylethyl, 2,2-diphenylethyl, 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, pentadeuterated phenyl, 2-methylphenyl, 2-iso propylphenyl, 2-ethylphenyl, 4-methylphenyl, 4-isopropylphenyl, 4-ethylphenyl, 4-tert-butylphenyl, 2,3-dimethylphenyl, 2,3-diethylphenyl, 2,3-diisopropylphenyl, 2,3-diisobutylphenyl, 2,3-dicyclohexylphenyl, 2,3-dicyclopropylphenyl, 2,3-dicyclobutylphenyl, 2,3-dicyclopentylphenyl, 2,4-dimethylphenyl, 2,4-diethylphenyl, 2,4-diisopropylphenyl, 2,4-diisobutylphenyl, 2,4-di Cyclohexylphenyl, 2,4-dicyclopropylphenyl, 2,4-dicyclobutylphenyl, 2,4-dicyclopentylphenyl, 2,6-dimethylphenyl, 2,6-diethylphenyl, 2,6-diisopropylphenyl, 2,6-diisobutylphenyl, 2,6-dicyclohexylphenyl, 2,6-dicyclopropylphenyl, 2,6-dicyclobutylphenyl, 2,6-dicyclopentylphenyl, 3,5-dimethylphenyl, 3,5-diethylphenyl, 3,5-diisopropylphenyl, 3,5-diisobutylphenyl, 3,5-dicyclohexyl Phenyl, 3,5-dicyclopropylphenyl, 3,5-dicyclobutylphenyl, 3,5-dicyclopentylphenyl, 2,3,5,6-tetramethylphenyl, 2,4,6-trimethylphenyl, 2,4,6-triethylphenyl, 2,4,6-triisopropylphenyl, 2,4,6-triisobutylphenyl, 2,4,6-tricyclohexylphenyl, 2,4,6-tricyclopropylphenyl, 2,4,6-tricyclobutylphenyl, 2,4,6-tricyclopentylphenyl, cyano, biphenyl-2-yl and 4'-tert-butylbiphenyl-2-yl.

[0084] In some embodiments of the present invention, for the complex of formula (I) above, M is Pt; A is O; R1 is selected from isopropyl, pentadeuterated phenyl, 2,6-diisopropylphenyl and biphenyl-2-yl; and R2-R 17 They may be the same or different, and are each independently selected from hydrogen, deuterium, isopropyl, tert-butyl, and cyano groups.

[0085] In this invention, "hydrogen isotopes" can be selected from deuterium and tritium, with deuterium being preferred. In this invention, "halogen" refers to fluorine, chlorine, bromine, and / or iodine.

[0086] In some embodiments of the present invention, one or more hydrogen atoms in the divalent metal complex of formula (I) or formula (I') of the present invention may be replaced by deuterium.

[0087] According to the present invention, in some embodiments, in the divalent metal complex, such as a divalent platinum complex, R1-R 17 Each can be independently selected from deuterated substituents -CDH2, -CD2H, -CD3, -CDR. a R b or -CD2R a , where R a and R b Each is independently selected from H, C1-C 12 Alkyl, C5-C 30 Aromatic groups, C1-C 12 The above-mentioned substituents include alkoxy groups or hydrogen isotopes; the alkyl group includes unsubstituted straight-chain alkyl groups, substituted straight-chain alkyl groups, unsubstituted cycloalkyl groups, or substituted cycloalkyl groups; the aromatic group includes unsubstituted aryl groups, substituted aryl groups, aryloxy groups, arylamine groups, or heteroaryl groups; preferably, R a and R b Each is independently selected from H, C1-C 10 Alkyl or C5-C 24 Aromatic group; preferably, the alkyl group includes aryl-substituted alkyl, trimethylsilyl or haloalkyl, wherein the halogen in the haloalkyl group is selected from fluorine, chlorine, bromine and iodine; preferably, the aromatic group may include alkyl-substituted aryl or aryl-substituted aryl.

[0088] In this invention, it should be noted that, for example, in the "-CDH2" group, "C" refers to carbon and "D" refers to deuterium (D), an isotope of hydrogen, also called heavy hydrogen; the same applies to others.

[0089] According to the present invention, in some embodiments, in the divalent metal complex, such as a divalent platinum complex, R1-R 17 Each can be independently selected from deuterated aryl or substituted deuterated aryl-Ar-dn, wherein Ar is selected from unsubstituted aryl, aryl-substituted aryl, or alkyl-substituted aryl; the deuterated hydrogen d n It is selected from one deuterium substitution, multiple deuterium substitutions, or all hydrogens being substituted with deuterium.

[0090] According to the present invention, the divalent platinum complex of the present invention can be complex 1 to complex 30:

[0091]

[0092]

[0093]

[0094] A second aspect of the present invention provides a method for preparing the aforementioned divalent metal complex, the method comprising:

[0095] (1) Compound a shown in formula (a) is subjected to a first coupling reaction with phenol compound b shown in formula (b) to obtain compound c shown in formula (c);

[0096]

[0097] (2) The compound c shown in formula (c) is subjected to a functional group transformation reaction to obtain the compound shown in formula (d);

[0098]

[0099] (3) The compound d shown in formula (d) is subjected to a second coupling reaction with the compound h shown in formula (h) to obtain the compound shown in formula (e), and the compound e shown in formula (e) is subjected to a third coupling reaction with the amine compound i shown in formula (i) to obtain the compound f shown in formula (f); or, (4) The compound d shown in formula (d) is subjected to a third coupling reaction with the o-aniline compound j shown in formula (j) to obtain the compound f shown in formula (f);

[0100]

[0101] (5) The compound f shown in formula (f) is subjected to a ring-closure reaction to obtain the compound g shown in formula (g); preferably, the compound f shown in formula (f) is subjected to a ring-closure reaction with ammonium hexafluorophosphonate and triethyl orthoformate to obtain the compound g shown in formula (g);

[0102]

[0103] (6) In the presence of a divalent platinum or palladium compound, compound g of formula (g) is subjected to a cyclometalation reaction to obtain a divalent metal complex of formula (I);

[0104] Among them, the groups R1-R in formulas (I), (a), (b), (c), (d), (e), (f), (g), (h), (i), and (j) 17 The definition of A is the same as that described in the first aspect above;

[0105] In equations (a), (c), (e), (h), and (j), X may be the same or different, and may be F, Br, I, Cl, or OTf, respectively.

[0106] Preferably, the method of the present invention is a method for preparing divalent platinum complexes of formula (I'), the method comprising:

[0107] (1) Under a protective atmosphere, furan compound a shown in formula (a) and phenol compound b with a substituent shown in formula (b) are subjected to a first coupling reaction to obtain compound c shown in formula (c);

[0108] (2) Under a protective gas, compound c shown in formula (c) is subjected to a functional group transformation reaction, wherein the X group is changed to an amino group to obtain the compound shown in formula (d).

[0109] (3) Under a protective atmosphere, compound d of formula (d) is coupled with compound h of formula (h) which has a substituent to undergo a second coupling reaction to obtain compound (e); and compound e of formula (e) is coupled with amine compound i of formula R1-NH2 to undergo a third coupling reaction to obtain compound f of formula (f); or, (4) Under a protective atmosphere, compound d of formula (d) is coupled with o-aniline compound j of formula (j) to obtain compound f of formula (f);

[0110] (5) Under a protective atmosphere, compound f, as shown in formula (f), is reacted with ammonium hexafluorophosphonate and triethyl orthoformate to undergo a cyclization reaction to obtain compound g, as shown in formula (g);

[0111] (6) In the presence of cyclooctadienyl dichloride platinum(II) or dichloride platinum, compound g of formula (g) is subjected to a cyclometalation reaction to obtain the divalent platinum complex of formula (I');

[0112]

[0113]

[0114] The definitions of the groups in formulas (I'), (a), (b), (c), (d), (e), (f), (g), (h), and (j) are the same as those described in the first aspect above;

[0115] X in equations (a), (c), (e), (h), and (j) may be the same or different, and may be F, Br, I, Cl, or OTf, respectively.

[0116] In this invention, the protective gas can be selected from nitrogen, helium, neon, argon, etc.

[0117] In the method of the present invention, step (1) may include adding compound a of formula (a) and compound b of formula (b) into a reaction vessel, such as a sealed tube. The first coupling reaction may be carried out in the presence of a first catalyst, a first ligand, a first base, and a first solvent. The first catalyst may be a copper catalyst; the copper catalyst may be selected from one or more of cuprous iodide, cuprous bromide, cuprous chloride, and cuprous oxide. The first ligand may be selected from N... 1 N 2 -Dimethylethane-1,2-diamine, 2,2,6,6-tetramethylheptanedione, N 1 N 2 -One or more of bis(5-methyl-[1,1'-biphenyl]-2-yl)oxalamide, trans-cyclohexanediamine, and 1-methylimidazole. The first base may be an inorganic base, wherein the inorganic base may be one or more selected from cesium carbonate, potassium carbonate, potassium phosphate, cesium fluoride, and potassium hydroxide. The first solvent may be one or more selected from dimethyl sulfoxide, N,N-dimethylformamide, 1,4-dioxane, ethylene glycol dimethyl ether, deionized water, and toluene.

[0118] According to the present invention, in step (1), the molar ratio of compound a shown in formula (a), compound b shown in formula (b), the first catalyst, the first ligand, and the first base can be (0.5-3):1:(0.01-0.3):(0.01-0.5):(1-5); preferably (1-1.5):1:(0.01-0.1):(0.01-0.4):(1.2-3), more preferably (1-1.2):1:(0.02-0.04):(0.02-0.04):(1.2-1.5).

[0119] According to the present invention, in step (1), the conditions for the first coupling reaction may include: a temperature of 90-130°C and a time of 5-36h; preferably, a temperature of 100-110°C and a time of 7-9h.

[0120] In the method of the present invention, step (2) may include adding compound c, representing formula (c), and an ammonia source (a substance that converts the X group, such as a halogen, into an amino group) into a reaction vessel, such as a sealed tube. The reaction in step (2) may be carried out in the presence of a second catalyst, a second ligand, a second base, and a second solvent. In the present invention, the ammonia source may be one or more selected from ammonia water, liquid ammonia, benzylamine, and trifluoroacetamide. The reaction that converts the X group, such as a halogen, into an amino group typically uses a second catalyst, which may be a copper catalyst or a palladium catalyst; preferably, the copper catalyst may be one or more selected from cuprous iodide, cuprous bromide, and cuprous chloride, and the palladium catalyst may be one or more selected from tris(dibenzylacetone)palladium, tetra(triphenylphosphine)palladium, and palladium acetate. The second ligand may be selected from phosphine ligands, N... 1 N 2 -Dimethylethane-1,2-diamine, transcyclohexanediamine, 1-methylimidazole, and L-proline; wherein the phosphine ligand may be one or more selected from 2-(di-tert-butylphosphine)biphenyl, 2-dicyclohexylphosphine-2',4',6'-triisopropylbiphenyl, 2-dicyclohexylphosphine-2',6'-dimethoxy-biphenyl, and 1,1'-binaphthyl-2,2'-bisdiphenylphosphine. The second base may be an inorganic base or an organic base, wherein the inorganic base may be one or more selected from cesium carbonate, potassium carbonate, potassium phosphate, cesium fluoride, and potassium hydroxide, and the organic base may be one or more selected from sodium tert-butoxide, potassium tert-butoxide, and lithium tert-butoxide. The second solvent may be one or more selected from dimethyl sulfoxide, N,N-dimethylformamide, 1,4-dioxane, ethylene glycol dimethyl ether, deionized water, and toluene.

[0121] According to the present invention, in step (2), the molar ratio of compound c shown in formula (c), ammonia source, second catalyst, second ligand and second base can be 1:(1-5):(0.01-1):(0.01-1.5):(1-6); preferably 1:(2.0-3.0):(0.01-0.5):(0.01-1.0):(1-4), more preferably 1:(2.0-2.5):(0.02-0.04):(0.04-0.06):(1.5-2.5).

[0122] According to the present invention, in step (2), the reaction conditions may include: a temperature of 90-130°C and a time of 8-25h, preferably a temperature of 100-120°C and a time of 12-15h.

[0123] In this invention, when the X group, such as a halogen, is converted to an amino group, it may become an amine with a protecting group, which requires the removal of the protecting group. To remove the protecting group, reduction can be performed under a protective H2 gas atmosphere using palladium / carbon reduction, or reduction can be performed using iron powder as a reducing agent. The solvent can be a protic solvent such as methanol, ethanol, or tetrahydrofuran. The molar ratio of the amine with the protecting group to the reducing agent can be 1:(0.01-0.5); preferably 1:(0.05-0.1), more preferably 1:(0.1-0.3); and the required temperature can be room temperature, and the time can be 8-25 h, preferably 12-15 h.

[0124] In the method of the present invention, step (3) may include adding compound d of formula (d) and compound h of formula (h) into a reaction vessel, such as a sealed tube, to carry out a second coupling reaction to obtain the compound of formula (e). The second coupling reaction may be carried out in the presence of a third catalyst, a third ligand, a third base, and a third solvent. The third catalyst in the reaction may be a copper catalyst or a palladium catalyst. The copper catalyst may be one or more selected from cuprous iodide, cuprous bromide, and cuprous chloride, and the palladium catalyst may be one or more selected from tris(dibenzylacetone)palladium, tetraphenylphosphine palladium, and palladium acetate. The third ligand may be selected from phosphine ligands, N... 1 N 2 -Dimethylethane-1,2-diamine, 2,2,6,6-tetramethylheptanedione, N 1 N 2 -One or more of bis(5-methyl-[1,1'-biphenyl]-2-yl)oxalamide, trans-cyclohexanediamine, 1-methylimidazolium, and L-proline, wherein the phosphine ligand may be one or more selected from 2-(di-tert-butylphosphine)biphenyl, 2-dicyclohexylphosphine-2',4',6'-triisopropylbiphenyl, 2-dicyclohexylphosphine-2',6'-dimethoxy-biphenyl, and 1,1'-binaphthyl-2,2'-bisdiphenylphosphine. The third base may be an inorganic or organic base; the inorganic base may be one or more selected from cesium carbonate, potassium carbonate, potassium phosphate, cesium fluoride, and potassium hydroxide, and the organic base may be one or more selected from sodium tert-butoxide, potassium tert-butoxide, and lithium tert-butoxide. The third solvent may be one or more selected from dimethyl sulfoxide, N,N-dimethylformamide, 1,4-dioxane, ethylene glycol dimethyl ether, deionized water, and toluene.

[0125] According to the present invention, in step (3), the molar ratio of compound d represented by formula (d), compound h represented by formula (h), the third catalyst, the third ligand and the third base can be 1:(1-3):(0.01-0.5):(0.01-1):(0.5-5); preferably 1:(1-1.5):(0.05-0.1):(0.1-0.2):(1-3), more preferably 1:(1.1-1.2):(0.05-0.08):(0.1-0.2):(1.5-2).

[0126] According to the present invention, in step (3), the conditions for the second coupling reaction may include: a temperature of 90-150°C and a time of 11-25h, preferably a temperature of 130-140°C and a time of 20-23h.

[0127] According to the present invention, step (3) may further include adding compound e of formula (e) and a substituent-containing amine (e.g., amine compound i of formula (i) or R1-NH2) to a reaction vessel, such as a sealed tube, to carry out a third coupling reaction to obtain compound f of formula (f); or, step (4) may include adding compound d of formula (d) and o-aniline compound j of formula (j) to a reaction vessel, such as a sealed tube, to carry out a third coupling reaction to obtain compound f of formula (f). The third coupling reaction may be carried out in the presence of a fourth catalyst, a fourth ligand, a fourth base, and a fourth solvent. The fourth catalyst in this reaction may be a copper catalyst or a palladium catalyst. The copper catalyst may be one or more selected from cuprous iodide, cuprous bromide, and cuprous chloride, and the palladium catalyst may be one or more selected from tris(dibenzylacetone)dipalladium, tetratriphenylphosphine palladium, and palladium acetate. The fourth ligand may be selected from phosphine ligands, N... 1 N 2 -Dimethylethane-1,2-diamine, 2,2,6,6-tetramethylheptanedione, N 1 N 2-One or more of bis(5-methyl-[1,1'-biphenyl]-2-yl)oxalamide, trans-cyclohexanediamine, 1-methylimidazolium, and L-proline, wherein the phosphine ligand may be one or more selected from 2-(di-tert-butylphosphine)biphenyl, 2-dicyclohexylphosphine-2',4',6'-triisopropylbiphenyl, 2-dicyclohexylphosphine-2',6'-dimethoxy-biphenyl, and 1,1'-binaphthyl-2,2'-bisdiphenylphosphine. The fourth base may be an inorganic or organic base; the inorganic base may be one or more selected from cesium carbonate, potassium carbonate, potassium phosphate, cesium fluoride, and potassium hydroxide; and the organic base may be one or more selected from sodium tert-butoxide, potassium tert-butoxide, and lithium tert-butoxide. The fourth solvent may be one or more selected from dimethyl sulfoxide, N,N-dimethylformamide, 1,4-dioxane, ethylene glycol dimethyl ether, deionized water, and toluene.

[0128] According to the present invention, in step (3), the molar ratio of compound e shown in formula (e), amine compound i with substituents, fourth catalyst, fourth ligand and fourth base can be 1:(1-5):(0.05-1):(0.01-1):(1-6); preferably 1:(1-2.5):(0.05-0.6):(0.01-1):(1-4), more preferably 1:(1.1-1.5):(0.05-0.2):(0.05-0.08):(1.5-3).

[0129] According to the present invention, in step (4), the molar ratio of compound d represented by formula (d), o-aniline compound j represented by formula (j), the fourth catalyst, the fourth ligand and the fourth base can be 1:(1-5):(0.05-1):(0.01-1):(1-6); preferably 1:(1-2.5):(0.05-0.6):(0.01-1):(1-4), more preferably 1:(1.1-1.5):(0.05-0.2):(0.05-0.08):(1.5-3).

[0130] According to the present invention, in steps (3) and (4), the conditions for the third coupling reaction may include: a temperature of 100-150°C and a time of 8-25h, preferably a temperature of 120-130°C and a time of 20-23h.

[0131] In the method of the present invention, step (5) may include adding compound f of formula (f) into a reaction vessel, such as a sealed tube, to carry out a ring-closure reaction to obtain compound g of formula (g); preferably, step (5) includes adding compound f of formula (f), ammonium hexafluorophosphonate, and triethyl orthoformate into a reaction vessel, such as a sealed tube, to carry out a ring-closure reaction to obtain compound g of formula (g). Triethyl orthoformate may also be used as a solvent in the ring-closure reaction.

[0132] According to the present invention, in step (5), the molar ratio of compound f shown in formula (f) to ammonium hexafluorophosphonate can be 1: (1-3); preferably 1: (1-1.5), more preferably 1: (1.1-1.3).

[0133] According to the present invention, in step (5), the conditions for the ring-closing reaction may include: a temperature of 110-130°C and a time of 23-25h, preferably a temperature of 120-125°C and a time of 24-25h.

[0134] According to the present invention, step (6) may include cyclometalating compound g as shown in formula (g) in the presence of a divalent platinum or palladium compound to obtain a divalent metal complex as shown in formula (I); preferably, step (6) may include cyclometalating compound g as shown in formula (g) in the presence of cyclooctadienyl dichloride platinum(II) or platinum dichloride to obtain a divalent platinum complex as shown in formula (I'). The cyclometalation reaction may include mixing compound g as shown in formula (g), a divalent platinum or palladium compound such as cyclooctadienyl dichloride platinum(II) or platinum dichloride, sodium acetate, and a solvent tetrahydrofuran or N,N-dimethylformamide uniformly and reacting them.

[0135] According to the present invention, in step (6), the molar ratio of compound g represented by formula (g), divalent platinum or palladium compound such as cyclooctadienyl dichloride (II) or dichloride is 1:(0.5-3), preferably 1:(0.5-1.1), and more preferably 1:(0.9-1).

[0136] According to the present invention, in step (6), the conditions for the ring metallization reaction may include: heating to 100-140°C and stirring for 71-75 h in the presence of a protective gas, such as in a nitrogen environment, preferably heating to 120-130°C and stirring for 72-74 h.

[0137] According to the present invention, in some embodiments, the method for synthesizing the divalent platinum complex of the present invention may include, for example: Figure 15 The process shown; preferably, in this invention, according to Figure 15 The process shown is used to synthesize the divalent platinum complex of the present invention.

[0138] In this invention, the first coupling reaction may be a Ullmann coupling reaction; and / or the second coupling reaction may be a Ullmann coupling reaction or a Buchwald-Hartwig coupling reaction; and / or the third coupling reaction may be a Ullmann coupling reaction or a Buchwald-Hartwig coupling reaction. Ullmann coupling reactions and Buchwald-Hartwig coupling reactions are known in the art, and therefore those skilled in the art can select appropriate reaction conditions and parameters accordingly.

[0139] A third aspect of this invention provides the application of the divalent metal complex of this invention, such as a divalent platinum complex, in organic optoelectronic devices. The organic optoelectronic device may be a green phosphorescent organic optoelectronic device or a green phosphorescent organic electroluminescent device.

[0140] According to some embodiments of the present invention, the organic optoelectronic device includes a display device and / or a lighting device.

[0141] A fourth aspect of the present invention provides an organic optoelectronic device, preferably an organic electroluminescent device such as an OLED, wherein the device includes an anode layer, a light-emitting layer, and a cathode layer, the light-emitting layer comprising the divalent metal complex of the present invention, preferably a divalent platinum complex. In some embodiments, the device may include a substrate, an anode layer, a hole transport layer, a light-emitting layer, an electron transport layer, and a metal cathode layer, wherein at least one of the light-emitting layer, the electron transport layer, and the hole transport layer comprises the divalent metal complex of the present invention, preferably a divalent platinum complex; in some embodiments, preferably, the light-emitting layer comprises the divalent metal complex, preferably a divalent platinum complex.

[0142] According to the present invention, in some embodiments, the light-emitting layer contains the green phosphorescent divalent platinum complex of the present invention.

[0143] According to the present invention, the divalent metal complex, preferably the divalent platinum complex, is the luminescent material, host material, or guest material in the luminescent layer.

[0144] In some embodiments, the organic electroluminescent device of the present invention is an OLED. The structure of OLEDs is known in the art. The present invention can employ various OLED structures known in the art.

[0145] Figure 11 A structural diagram of an exemplary OLED light-emitting device is shown. Figure 11As shown, the OLED device includes an anode (typically a conductive and transparent material, such as indium tin oxide (ITO)), a hole injection layer (P-HIL or HIL), a hole transport layer (HTL), an emissive layer (EML), an electron transport layer (ETL), an electron injection layer (EIL), and a metal cathode layer (cathode). As is known to those skilled in the art, one or more layers may be omitted; for example, one or more of the hole injection layer (P-HIL or HIL), hole transport layer (HTL), electron transport layer (ETL), and electron injection layer (EIL) may be omitted.

[0146] As is known in the art, an EML can comprise one or more luminescent materials and one or more host materials. In this invention, the EML can comprise the divalent metal complex of this invention.

[0147] As is known in the art, EIL refers to the electron injection layer; it can also be considered part of ETL. HIL can be considered part of HTL. EIL, ETL, HTL, and HIL can be single-layered or multi-layered. In addition, the device may also include a cathode capping layer (CPL); its function is to adjust the optical path to improve light extraction efficiency.

[0148] In some implementations, ITO is used as the anode of the OLED device, and Al is used as the cathode. Therefore, the device structure can be: ITO / HIL (10nm) / HTL-1 (30nm) / HTL-2 (10nm) / EML (20nm, doped with 5wt% green light complex) / ETL (60nm) / EIL (2nm) / Al; where HIL is the hole injection layer, which may contain, but is not limited to, materials such as HATCN and MoO3; HTL is the hole transport layer, which may contain, but is not limited to, materials such as HATCN and MoO3. Limited to materials such as TAPC, NPD, TCTA, BPBPA, and 2,6-tBu-mCPy; the EML layer is the light-emitting layer, which is a blend layer of coordination compound and host material in a ratio of 5%:95%, wherein the host material may include, but is not limited to, CBP, mCBP, 2,6mCPy, mCP, DMIC-CZ, BQDBC, etc.; the EIL layer is the electron injection layer, which may include, but is not limited to, materials such as LiQ and LiF; the ETL layer is the electron transport layer, which may include, but is not limited to, TmPyPb, TPBi, DPPS, Bphen, BmPyPb, etc. As is known to those skilled in the art, the device may use materials known in the art other than those mentioned above.

[0149] The abbreviations and full names of the above materials are as follows:

[0150] HATCN (2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazabenzanphenanthrene, 2,3,6,7,10,11-Hexaazatriphenylenehexacabonitrile);

[0151] MoO3 (Molybdenum trioxide, Molybdenum(VI) oxide);

[0152] TAPC(4,4'-cyclohexylbis[N,N-bis(4-methylphenyl)aniline], 4,4'-cyclohexylidenebis[N,N-bis(p-tolyl)aniline];

[0153] NPD (N,N'-diphenyl-N,N'-bis(1-naphthalenyl)-1,1'-biphenyl-4,4'-diamine, N,N'-Bis-(1-naphthalenyl)-N,N'-bis-phenyl-(1,1'-biphenyl)-4,4'-diamine);

[0154] TCTA (4,4',4”-Tris(carbazol–9-yl)triphenylamine);

[0155] BPBPA (4,4'-bis[N,N-di(biphenyl-4-yl)amino]-1,1'-biphenyl, 4,4'-Bis[N,N-di(biphenyl-4-yl)amino]-1,1'-biphenyl);

[0156] 2,6-tBu-mCPy(2,6-bis(3,6-di-tert-butyl-9H-carbazol-9-yl)pyridine, 2,6-bis(3,6-di-tert-butyl-9H-carbazol-9-yl)pyridine);

[0157] CBP (4,4'-bis(9-carbazolyl)biphenyl, 4,4'-Bis(9-carbazolyl)-1,1'-biphenyl);

[0158] mCBP(3,3'-di(9H-carbazol-9-yl)-1,1'-biphenyl, 3,3'-Di(9H-carbazol-9-yl)-1,1'-biphenyl);

[0159] 2,6mCPy(2,6-Di(9H-carbazol-9-yl)pyridine);

[0160] mCP (1,3-Di-9-carbazolylbenzene, 1,3-Di-9-carbazolylbenzene)

[0161] DMIC-CZ(7,7-dimethyl-5-phenyl-2-(9-phenyl-9H-carbazole-3-yl)-5,7-dihydroindolo[2,1-b]carbazole,

[0162] 7,7-dimethyl-5-phenyl-2-(9-phenyl-9H-carzole-3-yl)-5,7-dihydroindeno[2,1-b]carbazole);

[0163] BQDBC(7-(4-([1,1'-biphenyl]-4-yl)quinazolin-2-yl)-7H-dibenzo[c,g]carbazole,CAS:1831055-87-80);

[0164] LiQ (8-Hydroxyquinolinolato-lithium);

[0165] LiF (Lithium fluoride);

[0166] TmPyPb(1,3,5-tri[(3-pyridyl)-phen-3-yl]benzene, 1,3,5-tri[(3-pyridyl)-phen-3-yl]benzene);

[0167] TPBi(1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene, 1,3,5-Tris(1-phenyl-1H-benzimidazol-2-yl)benzene);

[0168] DPPS (Diphenylbis(4-(pyridin-3-yl)phenyl)silane);

[0169] Bphen (4,7-diphenyl-1,10-phenanthroline);

[0170] BmPyPb(1,3-bis(3,5-dipyridin-3-yl)phenyl)benzene, 1,3-bis[3,5-di(pyridin-3-yl)phenyl]benzene);

[0171] Example

[0172] The present invention will be described in detail below through embodiments.

[0173] Testing of the luminescent properties of electroluminescent materials: CIE uses chromaticity coordinate parameters according to the International Commission on Illumination (ICI) standards.

[0174] 1H NMR spectroscopy was performed using a JEOL JNM-ECZ400S / L1 instrument. The complex was dissolved in deuterated chloroform or deuterated dimethyl sulfoxide containing tetramethylsilane (TMS) for 1H NMR analysis. 1 HNMR), with a frequency of 300MHz or 400MHz.

[0175] Mass spectrometry was performed using a Waters Corporation ACQUITY UPLCH-Class instrument; intermediate compounds were analyzed by electrospray ionization mass spectrometry (ESI-MS), and the final product was analyzed by matrix-assisted ionization time-of-flight mass spectrometry (MALDI-TOF-MS).

[0176] The photoluminescence peak, lifetime, and efficiency of the complex solution or thin film were measured using a Horiba Fluorolog-3 instrument. Room temperature dichloromethane solution spectra of platinum complexes and 5 wt% doped polymethyl methacrylate (PMMA) thin films were measured. Dichloromethane solution spectra were measured in a glove box after thorough nitrogen purging of the solvent. Polymer-doped thin films were prepared by spin-coating in a glove box using chloroform as solvent and a quartz sheet as the film carrier. Thin film samples were tested in a glove box or vacuum chamber to reduce the quenching effect of oxygen on the luminescence of the complexes. The photoluminescence quantum yield of the platinum complex solution was measured using an integrating sphere. Time-resolved spectroscopy and lifetime measurements were performed on room temperature dichloromethane solutions of platinum complexes, and lifetime measurements were performed on doped PMMA thin films. All tests were conducted under nitrogen or vacuum conditions.

[0177] The energy levels of the complexes were measured using an electrochemical workstation (model CHI600D) from Shanghai Chenhua Instrument Co., Ltd. A three-electrode system was used: a platinum column as the working electrode, a platinum wire as the counter electrode, and silver / silver chloride as the reference electrode. The samples were tested under a nitrogen atmosphere using ultra-dry dimethylformamide containing 0.1 M tetrabutylammonium hexafluorophosphate as the solvent, with ferrocene as the internal standard, at a scan rate of 100 mV / s.

[0178] Example 1

[0179] This example illustrates the preparation of complex 2.

[0180] Synthesis of c1:

[0181]

[0182] Add 3-(pyridin-2-yl)phenol (2.56 g, 15 mmol), 2-bromo-4-chlorodibenzo[b,d]furan (4.18 g, 15 mmol), cuprous iodide (0.3 mmol, 0.02 equiv), and BPPO (N) sequentially to a 200 mL sealed tube equipped with a magnetic rotor. 1 N 2 The mixture of bis(5-methyl-[1,1'-biphenyl]-2-yl)oxalamide (0.3 mmol, 0.02 equiv), K3PO4 (18 mmol, 1.2 equiv), and N,N-dimethylformamide (60 mL) was bubbled under nitrogen for 10 minutes and then heated to 100 °C and stirred for 8 hours. After cooling to room temperature, the reaction was quenched with water, extracted with ethyl acetate, and the combined organic phases were washed with a suitable amount of saturated sodium chloride aqueous solution and dried over anhydrous sodium sulfate. The solvent was removed by vacuum distillation, and the crude product was purified by silica gel column chromatography with petroleum ether:ethyl acetate = 15:1 as the eluent, yielding product c1 in 65% yield.

[0183] Synthesis of d1:

[0184]

[0185] Add C1 (3.71 g, 10 mmol), benzylamine (2.14 g, 20 mmol), tris(dibenzylacetone)palladium (0.2 mmol, 0.02 equiv), 2-(di-tert-butylphosphine)biphenyl (0.4 mmol, 0.04 equiv), sodium tert-butoxide (15 mmol, 1.5 equiv), and toluene (50 ml) to a 150 mL Shrek tube. Bubble the resulting mixture under nitrogen for 10 minutes and stir at 100 °C for 12 hours. After cooling, add water and ethyl acetate (EA), and filter the mixture. Extract the aqueous phase with ethyl acetate, combine the organic phases, wash with brine, and dry with anhydrous Na₂SO₄. Purify the obtained solution by silica gel chromatography using PE:EA = 10:1 as the eluent to give an intermediate (brown viscous liquid, 80% yield).

[0186] An intermediate (442 mg, 1 mmol), Pd / C (0.1 equiv), and ethanol (10 mL) were added to a 100 mL round-bottom flask. The resulting mixture was stirred at room temperature for 12 hours under hydrogen atmosphere. After the reaction was complete, the mixture was filtered and evaporated to dryness to give product d1 (pale yellow viscous liquid, 90% yield).

[0187] The synthesis of f1:

[0188]

[0189] Intermediate d1 (352 mg, 1 mmol), 2-bromo-N-isopropylaniline (234 mg, 1.1 mmol), tris(dibenzylacetone)palladium (45.5 mg, 0.05 mmol), 1,1'-binaphthyl-2,2'-bis(diphenylphosphine) (31.1 mg, 0.05 mmol), sodium tert-butoxide (144 mg, 1.5 mmol), and toluene (4 mL) were added to a sealed tube in a glove box. After bubbling with nitrogen for 15 minutes, the mixture was heated at 130 °C for 20 hours. After cooling, ethyl acetate was added, and the mixture was filtered. The aqueous phase was extracted with ethyl acetate, and the organic phases were mixed, washed with brine, and dried over anhydrous Na₂SO₄. The obtained solution was purified by silica gel chromatography using PE:EA = 6:1 as the eluent. The eluent was evaporated to dryness to give product f1 (a yellow viscous liquid, 85% yield).

[0190] Synthesis of g1:

[0191]

[0192] Intermediate f1 (485 mg, 1 mmol), ammonium hexafluorophosphate (180 mg, 1.1 mmol), and triethyl orthoformate (2 mL) were added to a sealed tube. The tube was heated at 120 °C overnight. After cooling to room temperature, ethyl acetate was added to precipitate a yellow precipitate, which was filtered to give product g1 (brown solid, 50% yield).

[0193] Synthesis of Complex 2:

[0194]

[0195] Carbene hexafluorophosphate g1 (641 mg, 1 mmol), dichloro(1,5-cyclooctadiene)platinum(II) (Pt(COD)Cl2, 336 mg, 0.9 mmol), sodium acetate (86 mg, 1.05 mmol), and THF (2 mL) were added to a sealed tube. The tube was heated at 120 °C for 3 days. After cooling to room temperature, the solution was evaporated to dryness. The solution was purified by silica gel chromatography using DCM:PE = 4:1 as the eluent to obtain the target product complex 2 (bright yellow powder, yield 40%).

[0196] The proton NMR spectra of complex 2 are as follows: 1H NMR (400MHz, CDCl3) δ9.24(d,J=8.4Hz,1H),9.00(d,J=4.8Hz,1H),7.98(d, J=7.6Hz,1H),7.89-7.81(m,2H),7.71(s,1H),7.65(d,J=8.4Hz,1H),7.59(d ,J=8.4Hz,1H),7.51-7.48(m,2H),7.45-7.41(m,1H),7.38-7.34(m,2H),7.3 1-7.27(m,2H),7.14-7.10(m,1H),5.63-5.56(m,1H),1.77(d,J=7.2Hz,6H).

[0197] MS(ESI): 689.3[M+H]+.

[0198] The emission peak in dichloromethane (DCM) solution is 533 nm with a half-width at half-maximum (FWHM) of 55 nm, while the emission peak in polymethyl methacrylate (PMMA) solution is 532 nm with an FWHM of 71 nm.

[0199] Example 2

[0200] This example illustrates the preparation of complex 4.

[0201] Synthesis of e2:

[0202]

[0203] Add d1 (3.52 g, 10 mmol), 1,2-dibromobenzene (2.57 g, 11 mmol), tris(dibenzylacetone)palladium (455 mg, 0.5 mmol), 2-(di-tert-butylphosphine)biphenyl (298 mg, 1 mmol), sodium tert-butoxide (1.44 g, 15 mmol), and toluene (40 mL) to a sealed tube in a glove box. After bubbling the mixture with nitrogen for 15 minutes, heat the mixture at 130 °C for 20 hours. After cooling, add ethyl acetate and filter the mixture. Extract the aqueous phase with ethyl acetate, and mix the organic phases, wash with brine, and dry with anhydrous Na2SO4. Use PE:EA = 6:1 as the eluent, and purify the obtained solution by silica gel chromatography. Rotate the eluent to dryness to give product e2 (yellow viscous liquid, yield 85%).

[0204] Composition of f2:

[0205]

[0206] Add e2 (506 mg, 1 mmol), 2,6-diisopropylaniline (195 mg, 1.1 mmol), tris(dibenzylacetone)palladium (45.5 mg, 0.05 mmol), 1,1'-binaphthyl-2,2'-bis(diphenylphosphine) (31.1 mg, 0.05 mmol), sodium tert-butoxide (144 mg, 1.5 mmol), and toluene (4 mL) to a sealed tube in a glove box. After bubbling the mixture under nitrogen for 15 minutes, heat the mixture at 130 °C for 20 hours. After cooling, add ethyl acetate and filter the mixture. Extract the aqueous phase with ethyl acetate, and mix the organic phases, wash with brine, and dry with anhydrous Na2SO4. Use PE:EA = 6:1 as the eluent, and purify the obtained solution by silica gel chromatography. Rotate the eluent to dryness to give product f2 (yellow viscous liquid, yield 85%).

[0207] Synthesis of g2:

[0208]

[0209] Add f2 (603 mg, 1 mmol), ammonium hexafluorophosphate (180 mg, 1.1 mmol), and triethyl orthoformate (2 mL) to a sealed tube. Heat at 120 °C for 24 hours. After cooling to room temperature, add ethyl acetate to precipitate a yellow precipitate, and filter to give product g2 (brown solid, 50% yield).

[0210] Synthesis of complex 4:

[0211]

[0212] Add g2 (760 mg, 1 mmol), dichloro(1,5-cyclooctadiene)platinum(II) (Pt(COD)Cl2, 336 mg, 0.9 mmol), sodium acetate (86 mg, 1.05 mmol), and THF (2 mL) to a sealed tube. Heat at 120 °C for 3 days. After cooling to room temperature, evaporate to dryness. Use DCM:PE = 4:1 as the eluent and purify the obtained solution by silica gel chromatography to obtain the target product complex 4 (bright yellow powder, yield 30%).

[0213] The proton NMR spectrum of complex 4: 1H NMR (400MHz, CDCl3) δ9.28 (d, J = 8.4Hz, 1H), 8.05-8.03 (m, 1H), 7.83 (s, 1H), 7. 79-7.70(m,3H),7.65-7.61(m,1H),7.56-7.53(m,2H),7.51-7.47(m,3H),7.42 -7.37(m,2H),7.35-7.29(m,2H),6.99-6.96(m,1H),6.90(d,J=8.0Hz,1H),6.4 5-6.41(m,1H),2.82-2.75(m,2H),1.07(d,J=6.8Hz,6H),1.04(d,J=6.8Hz,6H).

[0214] MS(ESI): 828.6 [M+Na] + .

[0215] The emission peak in dichloromethane (DCM) solution is 523 nm with a half-width at half-maximum (FWHM) of 26 nm, while the emission peak in polymethyl methacrylate (PMMA) solution is 522 nm with an FWHM of 24 nm.

[0216] Example 3

[0217] This example illustrates the preparation of complex 16.

[0218] Synthesis of c3:

[0219]

[0220] 3-(4-(tert-butyl)pyridin-2-yl)phenol (3.41 g, 15 mmol), 2-bromo-4-chlorodibenzo[b,d]furan (4.18 g, 15 mmol), cuprous iodide (0.3 mmol, 0.02 equiv), BPPO (0.3 mmol, 0.02 equiv), K3PO4 (18 mmol, 1.2 equiv), and N,N-dimethylformamide (60 mL) were added sequentially to a 200 mL sealed tube equipped with a magnetic rotor. The resulting mixture was bubbled under nitrogen for 10 minutes and then heated to 100 °C and stirred for 8 hours. After cooling to room temperature, the reaction was quenched with water, extracted with ethyl acetate, and the combined organic phases were washed with an appropriate amount of saturated sodium chloride aqueous solution and dried over anhydrous sodium sulfate. The solvent was removed by vacuum distillation, and the crude product was purified by silica gel column chromatography with petroleum ether:ethyl acetate = 15:1 as the eluent to give product c3 in 65% yield.

[0221] Synthesis of d3:

[0222]

[0223] Intermediate C3 (4.27 g, 10 mmol), benzylamine (2.14 g, 20 mmol), tris(dibenzylacetone)palladium (183 mg, 0.2 mmol), 2-(di-tert-butylphosphine)biphenyl (119 mg, 0.4 mmol), sodium tert-butoxide (1.44 g, 15 mmol), and toluene (40 mL) were added to a 150 mL Shrek tube. The resulting mixture was bubbled under nitrogen for 10 minutes and stirred at 100 °C for 12 hours. After cooling, water and ethyl acetate (EA) were added, and the mixture was filtered. The aqueous phase was extracted with ethyl acetate, and the organic phases were combined, washed with brine, and dried over anhydrous Na₂SO₄. The obtained solution was purified by silica gel chromatography using PE:EA = 10:1 as the eluent to give the intermediate (brown viscous liquid, yield 80%).

[0224] The intermediate (498 mg, 1 mmol), Pd / C (0.1 equiv), and ethanol (10 mL) were added to a 100 mL round-bottom flask. The resulting mixture was stirred at room temperature for 12 hours under hydrogen atmosphere. After the reaction was complete, the mixture was filtered and evaporated to dryness to give d3 (a pale yellow viscous liquid, 90% yield).

[0225] Synthesis of e3:

[0226]

[0227] Add d3 (4.08 g, 10 mmol), 1,2-dibromobenzene (2.57 g, 11 mmol), tris(dibenzylacetone)dipalladium (455 mg, 0.5 mmol), 2-(di-tert-butylphosphine)biphenyl (298 mg, 1 mmol), sodium tert-butoxide (1.44 g, 15 mmol), and toluene (40 mL) to a sealed tube in a glove box. After bubbling the mixture under nitrogen for 15 minutes, heat the mixture at 130 °C for 20 hours. After cooling, add ethyl acetate and filter the mixture. Extract the aqueous phase with ethyl acetate, and mix the organic phases, wash with brine, and dry with anhydrous Na2SO4. Use PE:EA = 6:1 as the eluent, and purify the obtained solution by silica gel chromatography. Rotate the eluent to dryness to give product e3 (yellow viscous liquid, yield 85%).

[0228] The synthesis of f3:

[0229]

[0230] Add e3 (562 mg, 1 mmol), 2,6-diisopropylaniline (195 mg, 1.1 mmol), tris(dibenzylacetone)palladium (45.5 mg, 0.05 mmol), 1,1'-binaphthyl-2,2'-bis(diphenylphosphine) (31.1 mg, 0.05 mmol), sodium tert-butoxide (144 mg, 1.5 mmol), and toluene (4 mL) to a sealed tube in a glove box. After bubbling the mixture under nitrogen for 15 minutes, heat the mixture at 130 °C for 20 hours. After cooling, add ethyl acetate and filter the mixture. Extract the aqueous phase with ethyl acetate, and mix the organic phases, wash with brine, and dry with anhydrous Na2SO4. Use PE:EA = 6:1 as the eluent, and purify the obtained solution by silica gel chromatography. Rotate the eluent to dryness to give product f3 (yellow viscous liquid, yield 85%).

[0231] Synthesis of g3:

[0232]

[0233] Add f3 (659 mg, 1 mmol), ammonium hexafluorophosphate (180 mg, 1.1 mmol), and triethyl orthoformate (2 mL) to a sealed tube. Heat at 120 °C for 24 hours. After cooling to room temperature, add ethyl acetate to precipitate a yellow precipitate, and filter to give product g3 (brown solid, 50% yield).

[0234] Synthesis of complex 16:

[0235]

[0236] Add g3 (816 mg, 1 mmol), dichloro(1,5-cyclooctadiene)platinum(II) (Pt(COD)Cl2, 336 mg, 0.9 mmol), sodium acetate (86 mg, 1.05 mmol), and THF (2 mL) to a sealed tube. Heat at 120 °C for 3 days. After cooling to room temperature, evaporate to dryness. Use DCM:PE = 4:1 as the eluent and purify the obtained solution by silica gel chromatography to obtain the target product complex 16 (bright yellow powder, yield 40%).

[0237] The proton NMR spectra of complex 16 are as follows: 1H NMR (400MHz, CDCl3) δ9.27 (d, J = 8.4Hz, 1H), 8.04 (d, J = 7.6Hz, 1H), 7.82 (s, 1H ),7.78-7.74(m,2H),7.71(d,J=8.0Hz,1H),7.55-7.49(m,5H),7.41-7.28(m, 5H),6.89(d,J=8.0Hz,1H),6.82(d,J=6.0Hz,1H),6.37(dd,J=6.0,2.4Hz,1H) ,2.83-2.76(m,2H),1.33(s,9H),1.05(d,J=6.8Hz,6H),1.03(d,J=6.8Hz,6H).

[0238] MS(ESI): 885.0 [M+Na] + .

[0239] The emission peak in dichloromethane (DCM) solution is 519 nm with a half-width at half-maximum (FWHM) of 24 nm, while the emission peak in polymethyl methacrylate (PMMA) solution is 521 nm with an FWHM of 23 nm.

[0240] Example 4

[0241] This example illustrates the preparation of complex 25.

[0242] F4 synthesis:

[0243]

[0244] Add e2 (562 mg, 1 mmol), [1,1'-biphenyl]-2-amine (186 mg, 1.1 mmol), tris(dibenzylacetone)dipalladium (45.5 mg, 0.05 mmol), 1,1'-binaphthyl-2,2'-bis(diphenylphosphine) (31.1 mg, 0.05 mmol), sodium tert-butoxide (144 mg, 1.5 mmol), and toluene (4 mL) to a sealed tube in a glove box. After bubbling the mixture under nitrogen for 15 minutes, heat the mixture at 130 °C for 20 hours. After cooling, add ethyl acetate and filter the mixture. Extract the aqueous phase with ethyl acetate, and mix the organic phases, wash with brine, and dry with anhydrous Na2SO4. Use PE:EA = 6:1 as the eluent, and purify the obtained solution by silica gel chromatography. Rotate the eluent to dryness to give product f4 (yellow viscous liquid, yield 85%).

[0245] Synthesis of g4:

[0246]

[0247] Add f4 (595 mg, 1 mmol), ammonium hexafluorophosphate (180 mg, 1.1 mmol), and triethyl orthoformate (2 mL) to a sealed tube. Heat at 120 °C for 24 hours. After cooling to room temperature, add ethyl acetate to precipitate a yellow precipitate, and filter to give product g4 (brown solid, 50% yield).

[0248] Synthesis of complex 25:

[0249]

[0250] Add g4 (752 mg, 1 mmol), dichloro(1,5-cyclooctadiene)platinum(II) (Pt(COD)Cl2, 336 mg, 0.9 mmol), sodium acetate (86 mg, 1.05 mmol), and THF (2 mL) to a sealed tube. Heat at 120 °C for 3 days. After cooling to room temperature, evaporate to dryness. Use DCM:PE = 4:1 as the eluent and purify the obtained solution by silica gel chromatography to obtain the target product complex 25 (bright yellow powder, yield 40%).

[0251] The proton NMR spectra of complex 25 are as follows: 1 H NMR (400MHz, CDCl3) δ9.16 (d, J = 8.4 Hz, 1H), 8.02 (d, J = 7.6, 1H), 7.87-7.81 (m, 3H), 7.77-7.72 (m, 2H), 7.65-7.61 (m, 2H), 7.56-7 .48(m,5H),7.47-7.38(m,3H),7.36-7.30(m,2H),7.23-7.13(m,3H),7.11-7.07(m,1H),6.80(d,J=8.0Hz,1H),6.46-6.43(m,1H).

[0252] MS (ESI): 828.3 [M+CH3OH] + .

[0253] The emission peak in dichloromethane (DCM) solution is 527 nm with a half-width at half-maximum (FWHM) of 28 nm. The emission peak in polymethyl methacrylate (PMMA) solution is also 527 nm with an FWHM of 28 nm.

[0254] Example 5

[0255] This embodiment illustrates the preparation of complex 19.

[0256] Synthesis of e5:

[0257]

[0258] Add d3 (4.08 g, 10 mmol), 1,2-dibromo-4-isocumene (3.34 g, 12 mmol), tris(dibenzylacetone)dipalladium (733 mg, 0.8 mmol), 2-(di-tert-butylphosphine)biphenyl (596 mg, 2 mmol), sodium tert-butoxide (1.92 g, 20 mmol), and toluene (40 mL) to a sealed tube in a glove box. After bubbling the mixture with nitrogen for 15 minutes, heat the mixture at 130 °C for 20 hours. After cooling, add ethyl acetate and filter the mixture. Extract the aqueous phase with ethyl acetate, and mix the organic phases, wash with brine, and dry with anhydrous Na2SO4. Use PE:EA = 6:1 as the eluent, and purify the obtained solution by silica gel chromatography. Rotate the eluent to dryness to give product e5 (yellow viscous liquid, yield 68%).

[0259] F5 synthesis:

[0260]

[0261] Add e5 (605 mg, 1 mmol), phenyl-d5-amine (148 mg, 1.5 mmol), tris(dibenzylacetone)palladium (183 mg, 0.2 mmol), 2-(di-tert-butylphosphine)biphenyl (31.1 mg, 0.08 mmol), sodium tert-butoxide (144 mg, 1.5 mmol), and toluene (4 mL) to a sealed tube in a glove box. After bubbling the mixture under nitrogen for 15 minutes, heat the mixture at 130 °C for 20 hours. After cooling, add ethyl acetate and filter the mixture. Extract the aqueous phase with ethyl acetate, and mix the organic phases, wash with brine, and dry with anhydrous Na₂SO₄. Use PE:EA = 6:1 as the eluent, and purify the obtained solution by silica gel chromatography. Rotate the eluent to dryness to give product f5 (yellow viscous liquid, yield 60%).

[0262] Synthesis of g5:

[0263]

[0264] Add f5 (623 mg, 1 mmol), ammonium hexafluorophosphate (212 mg, 1.3 mmol), and triethyl orthoformate (2 mL) to a sealed tube. Heat at 120 °C for 25 hours. After cooling to room temperature, add ethyl acetate to precipitate a yellow precipitate, and filter to give product g5 (brown solid, yield 55%).

[0265] Synthesis of complex 19:

[0266]

[0267] Add g5 (780 mg, 1 mmol), dichloro(1,5-cyclooctadiene)platinum(II) (Pt(COD)Cl2, 370 mg, 1 mmol), sodium acetate (86 mg, 1.05 mmol), and THF (2 mL) to a sealed tube. Heat at 120 °C for 3 days. After cooling to room temperature, evaporate to dryness. Use DCM:PE = 4:1 as the eluent and purify the obtained solution by silica gel chromatography to obtain the target product complex 19 (bright yellow powder, yield 40%).

[0268] MS (ESI): 856.3 [M+CH3OH] + .

[0269] The emission peak in dichloromethane (DCM) solution is 530 nm with a half-width at half-maximum (FWHM) of 48 nm, while the emission peak in polymethyl methacrylate (PMMA) solution is 532 nm with an FWHM of 45 nm.

[0270] Example 6

[0271] This example illustrates the preparation of complex 20.

[0272] Synthesis of e6:

[0273]

[0274] Add d3 (4.08 g, 10 mmol), 3,4-dibromobenzyl nitrile (3.13 g, 12 mmol), tris(dibenzylacetone)dipalladium (733 mg, 0.8 mmol), 2-(di-tert-butylphosphine)biphenyl (596 mg, 2 mmol), sodium tert-butoxide (1.92 g, 20 mmol), and toluene (40 mL) to a sealed tube in a glove box. After bubbling the mixture under nitrogen for 15 minutes, heat the mixture at 130 °C for 20 hours. After cooling, add ethyl acetate and filter the mixture. Extract the aqueous phase with ethyl acetate, and mix the organic phases, wash with brine, and dry with anhydrous Na₂SO₄. Use PE:EA = 6:1 as the eluent, and purify the obtained solution by silica gel chromatography. Rotate the eluent to dryness to give product e6 (yellow viscous liquid, yield 62%).

[0275] F6 synthesis:

[0276]

[0277] Add e6 (588 mg, 1 mmol), 2,6-diisopropylaniline (265 mg, 1.5 mmol), tris(dibenzylacetone)palladium (183 mg, 0.2 mmol), 2-(di-tert-butylphosphine)biphenyl (31.1 mg, 0.08 mmol), sodium tert-butoxide (144 mg, 1.5 mmol), and toluene (4 mL) to a sealed tube in a glove box. After bubbling the mixture for 15 minutes, heat the mixture at 130 °C for 20 hours. After cooling, add ethyl acetate and filter the mixture. Extract the aqueous phase with ethyl acetate, and mix the organic phases, wash with brine, and dry with anhydrous Na₂SO₄. Use PE:EA = 6:1 as the eluent, and purify the obtained solution by silica gel chromatography. Rotate the eluent to dryness to give product f6 (yellow viscous liquid, 50% yield).

[0278] Synthesis of g6:

[0279]

[0280] Add f6 (685 mg, 1 mmol), ammonium hexafluorophosphate (212 mg, 1.3 mmol), and triethyl orthoformate (2 mL) to a sealed tube. Heat at 120 °C for 25 hours. After cooling to room temperature, add ethyl acetate to precipitate a yellow precipitate, and filter to give product g6 (brown solid, yield 55%).

[0281] Synthesis of complex 20:

[0282]

[0283] Add g6 (842 mg, 1 mmol), dichloro(1,5-cyclooctadiene)platinum(II) (Pt(COD)Cl2, 370 mg, 1 mmol), sodium acetate (86 mg, 1.05 mmol), and THF (2 mL) to a sealed tube. Heat at 120 °C for 3 days. After cooling to room temperature, evaporate to dryness. Use DCM:PE = 4:1 as the eluent and purify the obtained solution by silica gel chromatography to obtain the target product complex 20 (bright yellow powder, yield 40%).

[0284] MS(ESI): 888.7 [M+H] + .

[0285] The emission peak in dichloromethane (DCM) solution is 526 nm with a half-width at half-maximum (FWHM) of 34 nm, while the emission peak in polymethyl methacrylate (PMMA) solution is 530 nm with an FWHM of 30 nm.

[0286] Example 7

[0287] This example illustrates the preparation of complex 28.

[0288] F7 synthesis:

[0289]

[0290] Add e6 (588 mg, 1 mmol), [1,1'-biphenyl]-2-amine (254 mg, 1.5 mmol), tris(dibenzylacetone)palladium (183 mg, 0.2 mmol), 2-(di-tert-butylphosphine)biphenyl (31.1 mg, 0.08 mmol), sodium tert-butoxide (144 mg, 1.5 mmol), and toluene (4 mL) to a sealed tube in a glove box. After bubbling the mixture under nitrogen for 15 minutes, heat the mixture at 130 °C for 20 hours. After cooling, add ethyl acetate and filter the mixture. Extract the aqueous phase with ethyl acetate, and mix the organic phases, wash with brine, and dry with anhydrous Na₂SO₄. Use PE:EA = 6:1 as the eluent, and purify the obtained solution by silica gel chromatography. Rotate the eluent to dryness to give product f7 (yellow viscous liquid, yield 55%).

[0291] Synthesis of g7:

[0292]

[0293] Add f7 (677 mg, 1 mmol), ammonium hexafluorophosphate (212 mg, 1.3 mmol), and triethyl orthoformate (2 mL) to a sealed tube. Heat at 120 °C for 25 hours. After cooling to room temperature, add ethyl acetate to precipitate a yellow precipitate, and filter to give product g7 (brown solid, yield 53%).

[0294] Synthesis of complex 28:

[0295]

[0296] Add g7 (834 mg, 1 mmol), dichloro(1,5-cyclooctadiene)platinum(II) (Pt(COD)Cl2, 370 mg, 1 mmol), sodium acetate (86 mg, 1.05 mmol), and THF (2 mL) to a sealed tube. Heat at 120 °C for 3 days. After cooling to room temperature, evaporate to dryness. Use DCM:PE = 4:1 as the eluent and purify the obtained solution by silica gel chromatography to obtain the target product complex 28 (bright yellow powder, yield 34%).

[0297] MS(ESI): 880.8 [M+H] + .

[0298] The emission peak in dichloromethane (DCM) solution is 533 nm with a half-width at half-maximum (FWHM) of 42 nm, while the emission peak in polymethyl methacrylate (PMMA) solution is 535 nm with an FWHM of 34 nm.

[0299] Comparative Example 1

[0300] The complex of Comparative Example 1 was prepared using the same method as in Example 1, except that the main structure of the complex of Example 1 contained a dibenzofuran structural unit, while the complex of Comparative Example 1 was phenyl (see CN112125932A); both Example 1 and Comparative Example 1 had the same isopropyl substituent, and the complex of Comparative Example 1 had the following structure:

[0301]

[0302] Comparative Example 2

[0303] The complex of Comparative Example 2 was prepared using the same method as in Example 2, except that the main structure of the complex of Example 2 contained a dibenzofuran structural unit, while the complex of Comparative Example 2 was phenyl (see CN112125932A); both Example 2 and Comparative Example 2 had the same substituent 2,6-diisopropylphenyl, and the complex of Comparative Example 2 had the following structure:

[0304]

[0305] Test Example 1

[0306] Photophysical properties of platinum complexes 2, 4, 16, 19, 20, 25, and 28.

[0307] Representative data on emitter color purity were obtained from the emission spectra of PMMA (polymethyl methacrylate) films and dichloromethane solutions prepared using a 5% complex. Specifically, the complex was dissolved at 5% by weight in dichloromethane (DCM) to form a solution and in polymethyl methacrylate (PMMA) to obtain a film, and then the resulting solution or film was tested.

[0308] Parallel tests were conducted and compared with those of Comparative Examples 1-2; Table 1 shows the emission spectrum data of the complex.

[0309] The peak wavelengths of complexes 2, 4, 16, 19, 20, 25, and 28 prepared in Examples 1-7 of this invention are between 515 nm and 535 nm. The full width at half maximum (FWHM) of complexes 4, 16, and 25 prepared in Examples 2-4 are between 20 and 30 nm, all belonging to narrow-band green luminescent materials. Although the FWHM of complex 2 prepared in Example 1 is 55 nm / 71 nm, the luminescence lifetime of the film of complex 2 is slightly lower, and the photoluminescence quantum yield Φ is higher.

[0310] In Table 1, λ represents the peak wavelength of the divalent platinum complex dissolved in dichloromethane and doped in polymethyl methacrylate (PMMA) films, with FWHM being its full width at half maximum. Table 1 also provides the luminescence lifetime τ and photoluminescence quantum yield Φ in solution and film.

[0311] Table 1

[0312]

[0313] a / b Measurement data in dichloromethane solution / PMMA film.

[0314] The data above shows that the peak green light wavelength of the divalent platinum complex provided in the embodiments of the present invention is in the range of 515-535 nm. Compared with comparative examples 1 and 2 with the same substituents, the green light wavelength is red-shifted by about 10 nm, and the luminous efficiency is significantly improved, thus obtaining green light with higher saturation. Therefore, the divalent platinum complex can be used as a green phosphorus photoluminescent material or photoluminescent material that meets the requirements of high color purity luminescence for high-definition displays.

[0315] Figure 1-3 The emission spectra of divalent platinum complexes 2, 4, and 16 in solution and thin film are shown in turn. Under 380 nm ultraviolet light excitation, the emission wavelengths of the three complexes in dichloromethane solution are between 519 and 533 nm, and the emission wavelengths in polymethyl methacrylate (PMMA) are between 521 and 532 nm. The peak wavelengths of all complexes are in the green light region, and the full width at half maximum (FWHM) of the spectra is relatively narrow, indicating that these complexes are excellent green phosphorescent materials.

[0316] Figure 1This is a photoluminescence spectrum of complex 2 prepared in Example 1 of this invention in solution and film. The spectrum is a photoluminescence spectrum under 380 nm ultraviolet light excitation, i.e., a photoluminescence spectrum. The peak wavelength of the emission spectrum in the 5% mass concentration dichloromethane solution is 533 nm, and the half-width at half-maximum (WHM) is 55 nm. The peak wavelength of the emission spectrum in the polymethyl methacrylate (PMMA) film under 5% mass concentration doping is 532 nm, and the WHM is 71 nm. Both show a narrow-band green light spectrum, indicating that complex 2 is suitable for green phosphorescence applications. Under 380 nm ultraviolet light excitation, the emission wavelength in the dichloromethane solution is 533 nm, and the emission range of the complex mainly includes green and yellow regions. Due to the large intermolecular space in the solution, there is no obvious aggregated emission, exhibiting obvious single-molecule emission. In the PMMA film, the emission peak does not change significantly, but the WHM is significantly increased, and the emission region extends into the red region compared to the solution, indicating that the molecules have a significant aggregated emission effect. The width of the spectrum can be controlled by adjusting the doping concentration, which is also very beneficial for the preparation during the subsequent evaporation process.

[0317] Figure 2 This is the emission spectrum of complex 4 prepared in Example 2 of the present invention in solution and film; wherein, the peak wavelength of the emission spectrum of the dichloromethane solution is 523 nm and the half-width at half-maximum (WHM) is 26 nm; the peak wavelength of the emission spectrum of the polymethyl methacrylate (5%) film is 522 nm and the WHM is 24 nm. Figure 2 As shown, under 380 nm ultraviolet light excitation, the solution and the thin film exhibited similar emission spectra with comparable emission wavelengths and full width at half maximum (FWHM). Compared to the spectrum of complex 2, the emission peak was significantly blue-shifted by 10 nm, and the FWHM was significantly narrowed. Figure 2 This indicates that complex 4 has the advantages of stable emission spectrum and high color purity.

[0318] Figure 3 This is the emission spectrum of complex 16 prepared in Example 3 of this invention in solution and film. The peak wavelength of the emission spectrum from the dichloromethane solution is 519 nm, and the full width at half maximum (FWHM) is 24 nm. The peak wavelength of the emission spectrum from the polymethyl methacrylate (5%) film is 521 nm, and the FWHM is 23 nm. The emission spectrum of complex 16 is blue-shifted by 2-4 nm and narrower by 1-2 nm compared to complex 4, indicating that the introduction of the tert-butyl group in complex 16 can slightly improve the emission energy level and structural rigidity during the emission process. Under 380 nm ultraviolet light excitation, the solution and film showed similar emission spectra, with comparable emission wavelengths and FWHMs. This molecule is based on complex 4 with the addition of a tert-butyl group. Compared to the spectrum of complex 4, the emission peak is blue-shifted by 2-4 nm, and the FWHM is narrower; this indicates that this type of complex can control the overall emission range by adjusting the substituents, while retaining its high efficiency, narrow spectrum, and stable emission characteristics.

[0319] Figure 4 This is the UV-Vis absorption spectrum of complex 2 prepared in Example 1 of this invention. According to the absorption spectrum, the absorption spectrum of the dichloromethane solution of this complex has very high intensity in the 200-400 nm range, which is due to the transition at the ligand center. Specifically, the absorption at 300-400 nm belongs to the π-π* transition centered on furan in the complex, and the absorption peaks after 400 nm can be attributed to valence transfer transitions (MLCT) between the metal ion at the complex center and the ligand, and charge transfer transitions (LLCT) between different ligand parts. This indicates that such molecules have complex excitation transition characteristics and very efficient energy absorption, making them a preferred molecular structure for doping materials. The absorption peak between 400-480 nm is related to the charge transfer from the metal to the ligand (…). 1 The presence of MLCT transitions and a very pronounced absorption band indicates that this series of compounds exhibits strong [transition characteristics / attention]. 1 MLCT effect. This effect is believed to increase the phosphorescence efficiency of the molecules, making these complex molecules preferred as dopant materials for phosphorescent devices. Therefore, these complexes exhibit distinct ligand centers and metal-to-ligand charge transfer transition absorption characteristics, resulting in highly efficient energy absorption and making them a preferred molecular structure for dopant materials.

[0320] Figure 5 It is the complex 2 prepared in Example 1 of this invention. 1 H NMR spectrum; Figure 6 It is the complex 4 prepared in Example 2 of this invention. 1 H NMR spectrum; Figure 7 It is the complex 16 prepared in Example 3 of this invention. 1 H NMR spectrum. Figure 5 , Figure 6 and Figure 7 The proton nuclear magnetic resonance (NMR) spectrum confirmed that the complex was successfully prepared according to the present invention, and that the complex can exist independently and stably and can be separated, purified and characterized.

[0321] Figure 8 This is a purity characterization chromatogram of complex 25 prepared in Example 4 of the present invention. Ultra-high performance liquid chromatography (UHPLC) was used with a Waters ACQUITY H-class chromatograph, USA, with 100% water or methanol / water (10% / 90%) as the mobile phase for detection.

[0322] The figure shows a purity of 99.29%, indicating that the method provided by this invention can produce a product with ultra-high purity, and that the complex can be scaled up in a suitable manner.

[0323] Figure 9This is the mass spectrum of complex 25 prepared in Example 4 of the present invention; the mass spectrometry molecular signal shows that the M / Z (mass-to-charge ratio of ions) peak is 828.3, which is consistent with the molecular ion peak of compound 25, indicating that the structure of this complex is the designed structure.

[0324] Figure 10 This is the mass spectrum of complex 16 prepared in Example 3 of the present invention; the mass spectrometry molecular signal shows that the M / Z peak is 885.0, which is consistent with the molecular ion peak of compound 16, indicating that the structure of this complex is the designed structure.

[0325] Test Example 2

[0326] The band gap and related optical properties of coordination compounds 2, 4, 16, 19, 20, 25, 28 and comparative examples 1-2 are characterized as shown in Table 2 below.

[0327] Photoelectric energy level testing of electroluminescent materials: band gap value (E) of the material g The values ​​of the lowest unoccupied molecular orbital (LUMO) and highest occupied molecular orbital (HOMO) were determined by cyclic voltammetry (CV). The entire test was conducted in a glove box (Lab2000, Etelux) on a CHI600D electrochemical workstation (Shanghai Chenhua Instrument Co., Ltd.). A three-electrode system was constructed using a Pt column as the working electrode, Ag / AgCl as the reference electrode, and a Pt wire as the auxiliary electrode. The test medium was a 0.1M tetrabutylammonium hexafluorophosphate (Bu4NPF6) solution in dimethylformamide (DMF), and the measured potentials were all measured with ferrocene (Fc) added as an internal standard. In Table 2, the unit is electron volt (eV).

[0328] Table 2

[0329] coordination compounds <![CDATA[E HOMO / eV]]> <![CDATA[E LUMO / eV]]> Eg / eV Complex 2 -5.11 -2.55 2.56 Complex 4 -5.41 -2.50 2.91 Complex 16 -5.39 -2.42 2.97 Complex 19 -5.38 -2.43 2.95 Complex 20 -5.40 -2.48 2.92 Complex 25 -5.32 -2.53 2.79 Complex 28 -5.35 -2.41 2.94 Comparative Example 1 -5.11 -2.49 2.62 Comparative Example 2 -5.19 -2.42 2.77

[0330] As shown in Table 2, the complexes 2, 4, 16, 19, 20, 25, and 28 prepared in Examples 1-7 of this invention have different structures from those in Comparative Examples 1-2, resulting in different band gap values ​​(E). g The LUMO values ​​of complex 2 are not significantly different from those of complexes 4, 16, 19, 20, 25, and 28, but their HOMO values ​​differ considerably.

[0331] Application examples

[0332] OLED devices were fabricated by doping complexes 2, 4, 16, 19, 20, 25, 28, and comparative examples 1 and 2 into the host material, with a doping amount of 5%.

[0333] Figure 12The emission spectrum of the device prepared using platinum complex 4 is shown. The structure used is ITO / HATCN (10 nm) / TAPC (10 nm) / TCTA (8 nm) / 2,6mCPy:5wt% platinum complex (20 nm) / 2,6-tBumCPy (10 nm) / LiQ (2 nm) / Al (120 nm). As shown in the electroluminescence spectrum, the emission peak is located at 531 nm; compared with its photoluminescence peak in PMMA medium, it is redshifted by 9 nm, and the full width at half maximum (FWHM) is 29 nm, which is almost unchanged; it retains the luminescent properties of the luminescent complex itself; its chromaticity coordinates are calculated to be CIE (0.35, 0.63). The spectrum shown indicates that this device has a narrow band electroluminescence effect and is suitable for use as a green light-emitting device.

[0334] Figure 13 This is the EQE-current density curve of the OLED device prepared by complex 4.

[0335] The EQE plot shows that the external quantum efficiency of the device exceeds 15% at low current densities; as the current density increases, the device roll-off is small, especially at 1 mA / cm². 2 The external quantum efficiency at the current density is 14.8%, indicating that the device prepared by complex 4 has good luminescence stability. Figure 14 The graph shows the time-dependent decay of photoluminescence in the device prepared using complex 4. The OLED device prepared using complex 4 exhibits slow photoluminescence decay, with a lifetime of LT at a brightness of 1760 nits. 95 It can reach 160 hours.

[0336] The electroluminescence performance of the device was tested using an IVL testing device, and the device lifetime was measured using a lifetime testing device. The IVL testing device was a Fostar FS-MP96-H16, and the lifetime testing device was a Fostar FS-2000GA4-X16-H8.

[0337] Application test cases

[0338] As described in the application examples above, OLED light-emitting devices were prepared in place of complex 4 using complexes 2, 16, 19, 20, 25, 28, and the complexes prepared in comparative examples 1-2, and their performance was tested.

[0339] The performance data of the light-emitting devices prepared using divalent platinum complexes are shown in Table 3. CIE(x,y) refers to the chromaticity coordinate parameters according to the International Commission on Illumination (ICI) standard. The current efficiency (CE) and energy efficiency (PE) data are provided at a device luminance of 1000 cd·m². -2 The values ​​below.

[0340] Table 3

[0341]

[0342] Table 3 shows a comparison of the luminescent performance data of the light-emitting devices prepared from various platinum complexes. The electroluminescence wavelength of the light-emitting devices is mainly determined by the photoluminescence of the platinum complex itself, and the purity of the photoluminescence spectrum of the platinum complex itself is directly related to the spectral purity of the electroluminescence. Under the same conditions, the efficiency of the light-emitting devices also follows the trend of the luminescence quantum efficiency of the platinum complex itself, and the color purity of the light emitted by the light-emitting devices is directly related to the spectral color purity of the emitted light under photoexcitation of the doped material itself. A comparison of the electroluminescence spectrum of the platinum complex light-emitting devices and the photoluminescence spectrum in the thin film shows that, compared with the photoluminescence spectrum of the thin film, the electroluminescence spectrum of the light-emitting devices has a slight redshift, but the peak wavelength is still located in the green light region (530-540 nm), and most of the spectrum is also located in the green light range. The calculated chromaticity coordinates indicate that the light-emitting devices are green light-emitting devices and cover the green light range very well. The highest current efficiency (CE) of the light-emitting devices is 63.70 cd / A, and the highest energy efficiency (PE) is 81.30 lm / W.

[0343] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A divalent metal complex, characterized in that, The divalent metal complex has the structure shown in formula (I): In equation (I): M is Pt; A is O; R1 is a trideuterated methyl, a pentadeuterated phenyl, an optionally substituted C1-C6 alkyl group, or an optionally substituted C6-C6 alkyl group. 14 Aryl; R2-R 17 They may be the same or different, and each is independently selected from hydrogen atoms, hydrogen isotopes, halogen atoms, trideuterated methyl, cyano or optionally substituted C1-C6 alkyl groups; "Optionally substituted" means that the group is further substituted by or not by one or more groups selected from C1-C6 alkyl and halogen groups.

2. The divalent metal complex according to claim 1, wherein R1 is a trideuterated methyl, a pentadeuterated phenyl, an optionally substituted C1-C4 alkyl group, or an optionally substituted C6-C4 alkyl group. 14 Aryl; R2-R 17 They may be the same or different, and each is independently selected from hydrogen atoms, hydrogen isotopes, halogen atoms, trideuterated methyl, cyano or optionally substituted C1-C4 alkyl groups; "Optionally substituted" means that the group is further substituted by or not by one or more groups selected from C1-C4 alkyl and halogen groups.

3. The divalent metal complex according to claim 1, wherein, R1 is selected from methyl, trideuterated methyl, ethyl, 2,2,2-trifluoroethyl, n-propyl, isopropyl, 3,3,3-trifluoropropyl, 1,1,1,3,3,3-hexafluoro-2-propyl, n-butyl, isobutyl, hexafluoroisobutyl, tert-butyl, phenyl, pentadeuterated phenyl, 2-methylphenyl, 2-isopropylphenyl, 2-ethylphenyl, 4-methylphenyl, 4-isopropylphenyl, 4-ethylphenyl, 4-tert-butylphenyl, 2,3-dimethylphenyl, 2,3-diethylphenyl, 2,3-diisopropylphenyl, 2,3-diisobutylphenyl, 2,4-dimethylphenyl, 2 4-Diethylphenyl, 2,4-Diisopropylphenyl, 2,4-Diisobutylphenyl, 2,6-Dimethylphenyl, 2,6-Diethylphenyl, 2,6-Diisopropylphenyl, 2,6-Diisobutylphenyl, 3,5-Dimethylphenyl, 3,5-Diethylphenyl, 3,5-Diisopropylphenyl, 3,5-Diisobutylphenyl, 2,3,5,6-Tetramethylphenyl, 2,4,6-Trimethylphenyl, 2,4,6-Triethylphenyl, 2,4,6-Triisopropylphenyl, 2,4,6-Triisobutylphenyl, biphenyl-2-yl and 4'-tert-butylbiphenyl-2-yl; R2-R 17 The same or different, each independently selected from hydrogen atom, deuterium, halogen atom, methyl, trideuterated methyl, ethyl, 2,2,2-trifluoroethyl, n-propyl, isopropyl, 3,3,3-trifluoropropyl, 1,1,1,3,3,3-hexafluoro-2-propyl, n-butyl, isobutyl, hexafluoroisobutyl, tert-butyl and cyano.

4. The divalent metal complex according to any one of claims 1-2, wherein, R1 is selected from isopropyl, pentadeuterated phenyl, 2,6-diisopropylphenyl, and biphenyl-2-yl; and R2-R 17 They may be the same or different, and are each independently selected from hydrogen, deuterium, isopropyl, tert-butyl, and cyano groups.

5. The divalent metal complex according to any one of claims 1-2, wherein one or more hydrogen atoms in the divalent metal complex of formula (I) are replaced by deuterium.

6. The divalent metal complex according to any one of claims 1-2, wherein, The divalent metal complexes have the structures shown in complexes 1 to 30: 。 7. A method for preparing the divalent metal complex according to any one of claims 1-6, characterized in that, The method includes: (1) Compound a shown in formula (a) is subjected to a first coupling reaction with phenol compound b shown in formula (b) to obtain compound c shown in formula (c); (2) The compound c shown in formula (c) is subjected to a functional group transformation reaction to obtain the compound shown in formula (d); (3) The compound d shown in formula (d) is subjected to a second coupling reaction with the compound h shown in formula (h) to obtain the compound shown in formula (e), and the compound e shown in formula (e) is subjected to a third coupling reaction with the amine compound i shown in formula (i) to obtain the compound f shown in formula (f); or, (4) The compound d shown in formula (d) is subjected to a third coupling reaction with the o-aniline compound j shown in formula (j) to obtain the compound f shown in formula (f); (5) Compound f, as shown in formula (f), undergoes a ring-closure reaction to obtain compound g, as shown in formula (g); (6) In the presence of a divalent platinum compound, compound g shown in formula (g) is subjected to a cyclometalation reaction to obtain a divalent metal complex shown in formula (I); Among them, the groups R1-R in formulas (I), (a), (b), (c), (d), (e), (f), (g), (h), (i), and (j) 17 The definition of A is the same as that described in any one of claims 1-6; In equations (a), (c), (e), (h), and (j), X may be the same or different, and may be F, Br, I, Cl, or OTf, respectively.

8. The method according to claim 7, wherein the compound f shown in formula (f) is subjected to a cyclization reaction with ammonium hexafluorophosphate and triethyl orthoformate to obtain the compound g shown in formula (g).

9. The method according to claim 7 or 8, wherein the divalent metal complex is a divalent platinum complex of formula (I'), the method comprising: (1) Under a protective gas, furan compound a shown in formula (a) and phenol compound b shown in formula (b) are subjected to a first coupling reaction to obtain compound c shown in formula (c); (2) Under a protective gas, compound c shown in formula (c) is subjected to a functional group transformation reaction, wherein the X group is changed to an amino group to obtain the compound shown in formula (d). (3) Under a protective gas, compound d of formula (d) and compound h of formula (h) undergo a second coupling reaction to obtain compound (e); and compound e of formula (e) undergoes a third coupling reaction with amine compound i of formula R1-NH2 to obtain compound f of formula (f); or, (4) Under a protective gas, compound d of formula (d) and o-aniline compound j of formula (j) undergo a third coupling reaction to obtain compound f of formula (f); (5) Under a protective atmosphere, compound f, as shown in formula (f), is reacted with ammonium hexafluorophosphate and triethyl orthoformate to undergo a ring-closure reaction to obtain compound g, as shown in formula (g); (6) In the presence of cyclooctadienyl dichloride platinum(II) or dichloride platinum, compound g of formula (g) is subjected to a cyclometalation reaction to obtain the divalent platinum complex of formula (I'); Wherein, the definitions of the groups in formulas (I'), (a), (b), (c), (d), (e), (f), (g), (h), and (j) are the same as those in any one of claims 1-5; X in equations (a), (c), (e), (h), and (j) may be the same or different, and may be F, Br, I, Cl, or OTf, respectively.

10. The method according to claim 7 or 8, wherein: The first coupling reaction is an Ullmann coupling reaction; and / or The second coupling reaction is an Ullmann coupling reaction or a Buchwald-Hartwig coupling reaction; and / or The third coupling reaction is either the Ullmann coupling reaction or the Buchwald-Hartwig coupling reaction.

11. The method according to any one of claims 7-8, wherein, In step (1), the first coupling reaction is carried out in the presence of a first catalyst, a first ligand, a first base, and a first solvent; The first catalyst is a copper catalyst; the copper catalyst is selected from one or more of cuprous iodide, cuprous bromide, cuprous chloride, and cuprous oxide; The first ligand is selected from N 1 N 2 -Dimethylethane-1,2-diamine, 2,2,6,6-tetramethylheptanedione, N 1 N 2 One or more of bis(5-methyl-[1,1'-biphenyl]-2-yl)oxalamide, trans-cyclohexanediamine, and 1-methylimidazole; The first base is an inorganic base; the inorganic base is selected from one or more of cesium carbonate, potassium carbonate, potassium phosphate, cesium fluoride, and potassium hydroxide; The first solvent is selected from one or more of dimethyl sulfoxide, N,N-dimethylformamide, 1,4-dioxane, ethylene glycol dimethyl ether, deionized water and toluene; The molar ratio of compound a shown in formula (a), compound b shown in formula (b), the first catalyst, the first ligand, and the first base is (0.5-3):1:(0.01-0.3):(0.01-0.5):(1-5); The conditions for the first coupling reaction include: a temperature of 90-130℃ and a time of 5-36h.

12. The method according to any one of claims 7-8, wherein, In step (2), the functional group conversion reaction is carried out in the presence of an ammonia source, a second catalyst, a second ligand, a second base, and a second solvent; The ammonia source is selected from one or more of ammonia water, liquid ammonia, benzylamine, and trifluoroacetamide; The second catalyst is a copper catalyst or a palladium catalyst; The copper catalyst is selected from one or more of cuprous iodide, cuprous bromide and cuprous chloride; The palladium catalyst is selected from one or more of tris(dibenzylacetone)dipalladium, tetratriphenylphosphine palladium, and palladium acetate. The second ligand is selected from phosphine ligands, N 1 N 2 One or more of dimethylethane-1,2-diamine, transcyclohexanediamine, 1-methylimidazole, and L-proline; The phosphine ligand is selected from one or more of 2-(di-tert-butylphosphine)biphenyl, 2-dicyclohexylphosphine-2',4',6'-triisopropylbiphenyl, 2-dicyclohexylphosphine-2',6'-dimethoxy-biphenyl and 1,1'-binaphine-2,2'-bisdiphenylphosphine; The second base is an inorganic base or an organic base; The inorganic base is selected from one or more of cesium carbonate, potassium carbonate, potassium phosphate, cesium fluoride, and potassium hydroxide; The organic base is selected from one or more of sodium tert-butoxide, potassium tert-butoxide, and lithium tert-butoxide; The second solvent is selected from one or more of dimethyl sulfoxide, N,N-dimethylformamide, 1,4-dioxane, ethylene glycol dimethyl ether, deionized water, and toluene; The molar ratio of compound c shown in formula (c), ammonia source, second catalyst, second ligand and second base is 1:(1-5):(0.01-1):(0.01-1.5):(1-6); The conditions for the functional group transformation reaction include: a temperature of 90-130℃ and a time of 8-25h.

13. The method according to claim 9, wherein, The functional group transformation reaction further includes: removing the protection of the amino group generated in the halogen-to-amino conversion, wherein palladium / carbon or iron powder is used as a reducing agent for reduction; The molar ratio of the amine with the protecting group to the reducing agent is 1:(0.01-0.5).

14. The method according to any one of claims 7-8, wherein, In step (3), the second coupling reaction is carried out in the presence of a third catalyst, a third ligand, a third base, and a third solvent; The third catalyst is a copper catalyst or a palladium catalyst; The copper catalyst is selected from one or more of cuprous iodide, cuprous bromide and cuprous chloride; The palladium catalyst is selected from one or more of tris(dibenzylacetone)dipalladium, tetratriphenylphosphine palladium, and palladium acetate; The third ligand is selected from phosphine ligands, N... 1 N 2 -Dimethylethane-1,2-diamine, 2,2,6,6-tetramethylheptanedione, N 1 N 2 One or more of bis(5-methyl-[1,1'-biphenyl]-2-yl)oxalamide, trans-cyclohexanediamine, 1-methylimidazolium and L-proline; The phosphine ligand is selected from one or more of 2-(di-tert-butylphosphine)biphenyl, 2-dicyclohexylphosphine-2',4',6'-triisopropylbiphenyl, 2-dicyclohexylphosphine-2',6'-dimethoxy-biphenyl and 1,1'-binaphine-2,2'-bisdiphenylphosphine; The third alkali is an inorganic alkali or an organic alkali; The inorganic base is selected from one or more of cesium carbonate, potassium carbonate, potassium phosphate, cesium fluoride, and potassium hydroxide; The organic base is selected from one or more of sodium tert-butoxide, potassium tert-butoxide, and lithium tert-butoxide; The third solvent is selected from one or more of dimethyl sulfoxide, N,N-dimethylformamide, 1,4-dioxane, ethylene glycol dimethyl ether, deionized water and toluene; The molar ratio of compound d (shown in formula (d), compound h (shown in formula (h)), the third catalyst, the third ligand, and the third base is 1:(1-3):(0.01-0.5):(0.01-1):(0.5-5); The conditions for the second coupling reaction include: a temperature of 90-150℃ and a time of 11-25h.

15. The method according to any one of claims 7-8, wherein, In steps (3) and (4), the third coupling reaction is carried out in the presence of a fourth catalyst, a fourth ligand, a fourth base, and a fourth solvent; The fourth catalyst is a copper catalyst or a palladium catalyst; The copper catalyst is selected from one or more of cuprous iodide, cuprous bromide and cuprous chloride; The palladium catalyst is selected from one or more of tris(dibenzylacetone)dipalladium, tetratriphenylphosphine palladium, and palladium acetate; The fourth ligand is selected from phosphine ligands, N... 1 N 2 -Dimethylethane-1,2-diamine, 2,2,6,6-tetramethylheptanedione, N 1 N 2 One or more of bis(5-methyl-[1,1'-biphenyl]-2-yl)oxalamide, trans-cyclohexanediamine, 1-methylimidazolium and L-proline; The phosphine ligand is selected from one or more of 2-(di-tert-butylphosphine)biphenyl, 2-dicyclohexylphosphine-2',4',6'-triisopropylbiphenyl, 2-dicyclohexylphosphine-2',6'-dimethoxy-biphenyl and 1,1'-binaphine-2,2'-bisdiphenylphosphine; The fourth base is an inorganic base or an organic base; The inorganic base is selected from one or more of cesium carbonate, potassium carbonate, potassium phosphate, cesium fluoride, and potassium hydroxide; The organic base is selected from one or more of sodium tert-butoxide, potassium tert-butoxide, and lithium tert-butoxide; The fourth solvent is selected from one or more of dimethyl sulfoxide, N,N-dimethylformamide, 1,4-dioxane, ethylene glycol dimethyl ether, deionized water and toluene; The molar ratio of compound e (as shown in formula (e), amine compound i, fourth catalyst, fourth ligand, and fourth base) is 1:(1-5):(0.05-1):(0.01-1):(1-6), and / or the molar ratio of compound d (as shown in formula (d), o-aniline compound j (as shown in formula (j), fourth catalyst, fourth ligand, and fourth base) is 1:(1-5):(0.05-1):(0.01-1):(1-6); The conditions for the third coupling reaction include: a temperature of 110-150℃ and a time of 8-25h.

16. The method according to claim 8, wherein, In step (5), the molar ratio of compound f of formula (f) to ammonium hexafluorophosphate is 1:(1-3); The conditions for the ring-closing reaction include: a temperature of 110-130℃ and a time of 23-25h.

17. The method according to any one of claims 7-8, wherein, In step (6), the ring metallization reaction includes: mixing compound g (shown in formula (g), divalent platinum compound, sodium acetate, and solvent tetrahydrofuran or N,N-dimethylformamide evenly and reacting them; The molar ratio of compound g (shown in formula (g)) to divalent platinum compound is 1:(0.5-3); The conditions for the ring metallization reaction include: heating to 100-140°C and stirring for 71-75 hours in a nitrogen atmosphere.

18. The method of claim 17, wherein the divalent platinum compound is selected from cyclooctadienyl platinum dichloride and platinum dichloride.

19. The application of a divalent metal complex according to any one of claims 1-6 in organic optoelectronic devices.

20. The application according to claim 19, wherein the organic optoelectronic device is a green phosphorescent organic optoelectronic device.

21. The application according to claim 19, wherein the organic optoelectronic device is a green phosphorescent organic electroluminescent device.

22. An organic optoelectronic device, characterized in that, The device includes an anode layer, a light-emitting layer, and a cathode layer, wherein the light-emitting layer comprises a divalent metal complex as described in any one of claims 1-6.

23. The organic optoelectronic device according to claim 22, wherein the organic optoelectronic device is an organic electroluminescent device.

24. The organic optoelectronic device according to claim 22 or 23, characterized in that, The device comprises a substrate, an anode layer, a hole transport layer, a light-emitting layer, an electron transport layer, and a cathode layer, wherein the light-emitting layer comprises the divalent metal complex.

25. The organic optoelectronic device according to any one of claims 22-23, wherein, The divalent metal complex is the luminescent material in the luminescent layer.

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