An iridium metal complex and its applications, and organic electroluminescent devices

Abstract

This invention relates to the field of organic electroluminescent materials, specifically to an iridium metal complex, and more particularly to an iridium metal complex for deep red-near-infrared emission and its applications, as well as organic electroluminescent devices using the iridium metal complex of this invention. The iridium metal complex of this invention has the structure shown in formula (1). OLED devices prepared using the iridium metal complex of this invention exhibit higher luminous efficiency and better lifespan, demonstrating promising application prospects.

Description

Technical Field

[0001] This invention relates to the field of organic electroluminescent materials technology, specifically to an iridium metal complex, and more particularly to an iridium metal complex for deep red-near-infrared emission and its applications, as well as organic electroluminescent devices using the iridium metal complex of this invention. Background Technology

[0002] The near-infrared region refers to the electromagnetic spectrum range from 700 nanometers to 2500 nanometers. In recent years, near-infrared materials and technologies have attracted increasing attention and investment from the scientific community. In military applications, near-infrared technology is used for heat source target locking, regional defense, night vision equipment, missile positioning, and target tracking. In civilian applications, near-infrared technology can be used for thermal efficiency analysis, temperature remote sensing transmission, short-range wireless communication, and weather forecasting. In biological tissues and cells, near-infrared light can penetrate the surface and enter the tissues, avoiding interference from autofluorescence signals, making the near-infrared spectrum the optimal window for biological analysis. The near-infrared spectrum is also a window for fiber optic communication; near-infrared light sources with wavelengths of 1.31 and 1.55 micrometers can minimize fiber optic losses. Furthermore, nearly 50% of solar energy falls in the near-infrared region; to fully utilize this energy, it is necessary to develop new near-infrared photovoltaic materials.

[0003] Iridium metal complexes are excellent phosphorescent dyes due to their superior photophysical properties, and are widely used in organic light-emitting devices, sensors, and lasers. Currently, iridium metal complexes have achieved successful applications in the visible light region, including red, green, and blue light. However, research on iridium metal complexes in the near-infrared region still faces bottlenecks. The two main challenges are further redshifting the emission wavelength and improving near-infrared luminescence efficiency. To further redshift the emission wavelength of near-infrared luminescent materials, it is necessary to adjust the molecular structure to reduce the band gap between HOMO and LUMO. However, according to the band gap rule, as the band gap narrows, the rate of nonradiative relaxation of the excited state increases exponentially, leading to a sharp decrease in luminescence efficiency. Resolving the contradiction between wavelength redshift and decreased luminescence efficiency to obtain iridium metal complexes with pure near-infrared emission and high luminescence efficiency remains a key challenge in near-infrared luminescent material research.

[0004] Furthermore, achieving a redshift in the emission wavelength of iridium metal complexes typically requires the introduction of ligands with a higher degree of conjugation. The complex structure of these highly conjugated ligands not only increases the difficulty of synthesis and purification but also reduces the proportion of charge-transfer components between iridium and ligands in the frontier orbitals of the iridium metal complex, thus lowering the radiative transition rate of the excited state and leading to a further decrease in luminescence efficiency. Therefore, achieving a redshift in the emission wavelength to obtain near-infrared luminescent iridium metal complexes while maintaining a high proportion of charge-transfer components between iridium and ligands in the frontier orbitals requires careful consideration in molecular design. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides an iridium metal complex of near-infrared luminescent material that exhibits pure light color, simple structure, and high luminous efficiency.

[0006] Specifically, the present invention provides an iridium metal complex with the molecular formula L2IrA, wherein Ir is the central metal atom, L is the main ligand, and A is the auxiliary ligand. The general structural formula of the iridium metal complex of the present invention is shown in the following formula (1):

[0007]

[0008] In formula (1), Ar is selected from one of substituted or unsubstituted C6-C60 aryl or substituted or unsubstituted C4-C60 heteroaryl, and Ar is not selected from substituted or unsubstituted phenyl or substituted or unsubstituted pyridyl.

[0009] In formula (1), R represents a single substituted group up to the maximum permissible number of substituted groups, and R may be the same as or different from Ar; R is selected from one of hydrogen, deuterium, halogen, cyano, nitro, hydroxyl, aldehyde, silyl, amino, substituted or unsubstituted C1-C30 alkyl or cycloalkyl, substituted or unsubstituted C1-C30 haloalkyl or halocycloalkyl, substituted or unsubstituted C1-C30 alkoxy or thioalkoxy, substituted or unsubstituted C1-C30 carboxyl, substituted or unsubstituted C1-C30 ester, substituted or unsubstituted C1-C30 acyl, substituted or unsubstituted C6-C30 arylamino, substituted or unsubstituted C4-C30 heteroarylamino, substituted or unsubstituted C6-C30 aryl, and substituted or unsubstituted C4-C30 heteroaryl.

[0010] In formula (1), the auxiliary ligand A is selected from one of N^COOH, N^OH, β-diketone or N^NH;

[0011] When Ar and R are independently selected from groups having substituents, the substituents are selected from one or a combination of two of the following: deuterium, halogen, cyano, C1-C12 alkyl or haloalkyl, C3-C12 cycloalkyl or halocycloalkyl, C1-C12 alkoxy or thioalkoxy, C1-C10 silyl, amino, C6-C30 arylamino, C3-C30 heteroarylamino, C6-C30 aryl, and C3-C30 heteroaryl.

[0012] Furthermore, the iridium metal complex of the present invention has the structure shown in formula (2):

[0013]

[0014] In formula (2), the ranges of Ar, R and A are the same as those in general formula (1).

[0015] Preferably, in formulas (1) and (2), the Ar is selected from one of substituted or unsubstituted C6-C30 aryl and substituted or unsubstituted C4-C30 heteroaryl. When Ar has a substituent, the substituent is selected from one or a combination of two of the following: deuterium, fluorine, chlorine, cyano, C1-C6 alkyl, C1-C3 fluoroalkyl, C1-C3 chloroalkyl, C3-C10 cycloalkyl, C3-C10 fluorocycloalkyl, C3-C10 chlorocycloalkyl, C1-C12 alkoxy or thioalkoxy, C1-C10 silyl, amino, C6-C30 arylamino, C6-C30 aryl, and C3-C30 heteroaryl.

[0016] More preferably, the Ar is selected from the following groups, substituted or unsubstituted: thienyl, benzothienyl, dithienyl, trithienyl, dithienylphenyl, dibenzothienyl, N-phenyl-2-carbazolyl, naphthyl, anthraceneyl, phenanthryl, pyrene, furanyl, benzofuranyl, thiazolyl, benzothiazolyl, isothiazolyl, benzoisothiazolyl, pyrroleyl, benzopyrroleyl, imidazolyl, benzoimidazolyl, pyrazolyl, benzopyrazolyl, oxazolyl, benzooxazolyl, isoxazolyl, benzoisooxazolyl, pyrimidinyl, benzopyrimidinyl, pyrazinyl, benzopyrazinyl, pyridazinyl, benzopyridazinyl, quinolinyl, isoquinolinyl, purinyl, pteridinyl, pyridazinyl, indolyl, triphenylamine;

[0017] Preferably, the Ar is selected from the following groups, whether substituted or unsubstituted: thienyl, benzothienyl, dithienyl, trithienyl, dithienylphenyl, N-phenyl-2-carbazolyl, naphthyl, pyrene, benzofuranyl, triphenylamino;

[0018] More preferably, in formulas (1) and (2), R is selected from hydrogen, deuterium, halogen, cyano, nitro, hydroxyl, aldehyde, amino, substituted or unsubstituted C1-C20 alkyl or cycloalkyl, substituted or unsubstituted C1-C20 fluoroalkyl, substituted or unsubstituted C1-C20 chloroalkyl, substituted or unsubstituted C1-C20 alkoxy or thioalkoxy, substituted or unsubstituted C1-C20 carboxyl, substituted or unsubstituted C1-C20 ester, substituted or unsubstituted C1-C20 The R group is selected from one or a combination of two of the following: acyl, substituted or unsubstituted C6-C18 aryl, substituted or unsubstituted C4-C18 heteroaryl; when R has a substituent, the substituent is selected from one or a combination of two of the following: fluorine, chlorine, cyano, C1-C6 alkyl, C1-C3 fluoroalkyl, C1-C3 chloroalkyl, C3-C10 cycloalkyl, C3-C10 fluorocycloalkyl, C3-C10 chlorocycloalkyl, C1-C12 alkoxy or thioalkoxy, and C1-C10 silyl.

[0019] More preferably, R is selected from hydrogen, deuterium, fluorine, chlorine, cyano, C1-C6 alkyl, C1-C6 fluoroalkyl, C1-C6 chloroalkyl, or one of the following groups, substituted or unsubstituted: phenyl, biphenyl, thienyl, benzothienyl, dithienyl, trithienyl, dithienophenyl, dibenzothienyl, naphthyl, anthracene, phenanthrene, pyrene, furanyl, benzofuranyl, thiazolyl, benzothiazolyl, isothiazolyl, benzoisothiazolyl, pyridine Pyrrolyl, benzopyrrolyl, imidazolyl, benzoimidazolyl, pyrazolyl, benzopyrazole, oxazolyl, benzooxazolyl, isoxazolyl, benzoisooxazolyl, pyridyl, pyrimidinyl, benzopyrimidinyl, pyrazinyl, benzopyrazinyl, pyridazinyl, benzopyridazinyl, quinolinyl, isoquinolinyl, purine, pteridinyl, pyridazinyl, indolyl, carbazoleyl, diphenylamino, triphenylamino, phenoxazinyl, phenoxy, diphenylboryl, diphenylphosphino, diphenylphosphinooxy, triphenylsilyl.

[0020] More preferably, when Ar and R are each independently selected from groups having substituents, the substituents are selected from one or a combination of two of the following: deuterium, fluorine, chlorine, cyano, C1-C6 alkyl, C1-C3 fluoroalkyl, C1-C3 chloroalkyl, C3-C10 cycloalkyl, C3-C10 fluorocycloalkyl, C3-C10 chlorocycloalkyl, C1-C12 alkoxy or thioalkoxy, and C1-C10 silyl.

[0021] The iridium metal complex of the present invention is preferably a structure shown in any one of the following formulas (2-1), (2-2), (2-3), (2-4), (2-5), and (2-6):

[0022]

[0023] In equations (2-1), (2-2), (2-3), (2-4), (2-5), and (2-6), the ranges of R and A are the same as those in general equation (1);

[0024] R1 represents a single substituted group up to the maximum permissible number of substituted groups, and R1 is selected from hydrogen, deuterium, halogen, cyano, C1-C12 alkyl or haloalkyl, C3-C12 cycloalkyl or halocycloalkyl, C1-C12 alkoxy or thioalkoxy, C1-C12 silyl, amino, C6-C30 arylamino, C3-C30 heteroarylamino, C6-C30 aryl, and C3-C30 heteroaryl.

[0025] Preferably, in formulas (2-1), (2-2), (2-3), (2-4), (2-5), and (2-6), R and R1 are each independently selected from hydrogen, deuterium, fluorine, chlorine, cyano, C1-C6 alkyl, C1-C6 fluoroalkyl, C1-C6 chloroalkyl, or substituted or unsubstituted groups of the following: phenyl, thienyl, benzothienyl, dithienyl, trithienyl, dithienophenyl, dibenzothienyl, naphthyl, anthraceneyl, phenanthryl, pyrene, furanyl, benzofuranyl, thiazolyl, etc. Azolyl, benzothiazolyl, isothiazolyl, benzoisothiazolyl, pyrrolyl, benzopyrrolyl, imidazolyl, benzoimidazolyl, pyrrolyl, benzopyrrolyl, oxazolyl, benzooxazolyl, isoxazolyl, benzoisooxazolyl, pyridyl, pyrimidinyl, benzopyrimidinyl, pyrazinyl, benzopyrazinyl, pyridazinyl, benzopyridazinyl, quinolinyl, isoquinolinyl, purinel, pteridinyl, pyridazinyl, indolyl, carbazole, diphenylamino, triphenylamino, phenoxazinyl, phenoxy, diphenylboryl, diphenylphosphino, diphenylphosphinooxy, or triphenylsilyl;

[0026] When R and R1 are selected from substituents, the substituent is selected from one or a combination of two of the following: deuterium, fluorine, chlorine, cyano, C1-C6 alkyl, C1-C3 fluoroalkyl, C1-C3 chloroalkyl, C3-C10 cycloalkyl, C3-C10 fluorocycloalkyl, C3-C10 chlorocycloalkyl, C1-C12 alkoxy or thioalkoxy, and C1-C10 silyl.

[0027] More preferably, in formulas (2-1), (2-2), (2-3), (2-4), (2-5), and (2-6), R is selected from hydrogen, deuterium, or substituted or unsubstituted phenyl groups. When R is selected from substituted phenyl groups, the substituent on the phenyl group is selected from deuterium, methyl, trifluoromethyl, tert-butyl, phenyl, tert-butylphenyl, or trifluoromethylphenyl. R1 is selected from hydrogen, deuterium, methyl, trifluoromethyl, tert-butyl, hexyl, phenyl, tert-butylphenyl, or trifluoromethylphenyl.

[0028] In this specification, the "substituted or unsubstituted" group can replace one substituent or multiple substituents. When there are multiple substituents, they can be selected from different substituents. When the same expression is used in this invention, they all have the same meaning, and the selection range of substituents is as shown above and will not be repeated one by one.

[0029] In this specification, the expression Ca to Cb represents that the group has a to b carbon atoms. Unless otherwise specified, the number of carbon atoms generally does not include the number of carbon atoms of the substituents.

[0030] In this specification, the way a ring structure is represented by "—" indicates that the connection point is located at any position on the ring structure where bonding can occur.

[0031] In this specification, "each independently" means that when there are multiple subjects, they may be the same or different from each other.

[0032] In this specification, unless otherwise specified, the description of chemical elements usually includes the concept of their isotopes. For example, the description of "hydrogen (H)" includes its isotopes. 1 H (protium or H), 2 The concept of H (deuterium or D); carbon (C) includes... 12 C 13 C, etc., will not be elaborated further.

[0033] In this specification, the heteroatom in the heteroaryl group refers to an atom or group of atoms selected from N, O, S, P, Si and Se, preferably N, O and S.

[0034] Examples of halogens in this specification include fluorine, chlorine, bromine, and iodine.

[0035] In this specification, C6-C30 can be C6, C9, C10, C12, C14, C16, C18, C20, C22, C24, C26 or C28, etc.

[0036] C3-C30 can all be C3, C4, C5, C6, C9, C10, C12, C14, C16, C18, C20, C22, C24, C26 or C28, etc.

[0037] Each of C1-C12 can be C2, C3, C4, C5, C6, C7, C8, C9, C10, C11 or C12.

[0038] C3-C12 can all be C4, C5, C6, C7, C8, C9, C10, C11 or C12.

[0039] C2-C20 can all be C3, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C16, C17 or C18, etc.

[0040] C1-C30 can all be C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C16, C17, C18, C20, C22, C24, C26 or C28, etc.

[0041] C2-C30 can all be C3, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C16, C17, C18, C20, C22, C24, C26 or C28, etc.

[0042] C6-C60 can all be C6, C9, C10, C12, C14, C16, C18, C20, C22, C24, C26, C28, C30, C32, C34, C36, C38, C40, C42, C44, C46, ​​C48, C50, C52, C54, C56 or C58, etc.

[0043] The C3-C60 can all be C3, C4, C5, C6, C9, C10, C12, C14, C16, C18, C20, C22, C24, C26, C28, C30, C32, C34, C36, C38, C40, C42, C44, C46, ​​C48, C50, C52, C54, C56, or C58, etc.

[0044] In this specification, the substituted or unsubstituted C6-C30 aryl groups include monocyclic aryl groups and fused-ring aryl groups, with C6-C20 aryl groups being more preferred. A monocyclic aryl group refers to a molecule containing at least one phenyl group. When a molecule contains at least two phenyl groups, the phenyl groups are independent of each other and connected by a single bond, exemplarily including phenyl, biphenyl, and terphenyl. Specifically, the biphenyl group includes 2-biphenyl, 3-biphenyl, and 4-biphenyl; the terphenyl group includes p-terphenyl-4-yl, p-terphenyl-3-yl, p-terphenyl-2-yl, meta-terphenyl-4-yl, meta-terphenyl-3-yl, and meta-terphenyl-2-yl. A fused-ring aryl group refers to a molecule containing at least two aromatic rings, where the aromatic rings are not independent of each other but share two adjacent carbon atoms fused together. Examples include: naphthyl, anthracene, phenanthrene, indene, fluorenyl, fluoranthyl, triphenylene, pyrene, perylene, etc. Naphthyl, 2-naphthyl, and their derivative groups, etc. The naphthyl includes 1-naphthyl or 2-naphthyl; the anthraceneyl is selected from 1-anthrayl, 2-anthrayl, and 9-anthrayl; the fluorenyl is selected from 1-fluorenyl, 2-fluorenyl, 3-fluorenyl, 4-fluorenyl, and 9-fluorenyl; the pyrene is selected from 1-pyrene, 2-pyrene, and 4-pyrene; the 2-tetraphenyl is selected from 1-2 ... The fluorene derivative group is selected from 9,9-dimethylfluorenyl, 9,9-diethylfluorenyl, 9,9-dipropylfluorenyl, 9,9-dibutylfluorenyl, 9,9-dipentylfluorenyl, 9,9-dihexylfluorenyl, 9,9-diphenylfluorenyl, 9,9-dinaphthylfluorenyl, 9,9'-spirodifluorenyl, and benzo[a]fluorenyl.

[0045] In this specification, the substituted or unsubstituted C3-C30 heteroaryl groups include monocyclic heteroaryl groups and fused-ring heteroaryl groups, more preferably C4-C20 heteroaryl groups, and more preferably C5-C12 heteroaryl groups. A monocyclic heteroaryl group refers to a molecule containing at least one heteroaryl group. When a molecule contains one heteroaryl group and other groups (such as aryl, heteroaryl, alkyl, etc.), the heteroaryl group and the other groups are independent of each other and connected by a single bond. Examples of monocyclic heteroaryl groups include furanyl, thiophene, pyrrole, and pyridyl. A fused-ring heteroaryl group refers to a molecule containing at least one aromatic heterocycle and an aromatic ring (aromatic heterocycle or aromatic ring), and the two are not independent of each other but share a group consisting of two adjacent atoms fused together. Examples of fused-ring heteroaryl groups include: benzofuranyl, benzothiophenyl, isobenzofuranyl, indolyl, dibenzofuranyl, dibenzothiophenyl, carbazoyl, acridineyl, isobenzofuranyl, isobenzothiophenyl, benzocarbazoyl, azircarbazoyl, phenothiazinyl, phenothiazinyl, 9-phenylcarbazoyl, 9-naphthylcarbazoyl, dibenzocarbazoyl, indolocarbazoyl, etc.

[0046] In the ligand L of the iridium metal complex of this invention, the pyrido[3,4-b]pyrazine is used as the ligand backbone at the coordinating nitrogen end, which is equivalent to introducing two nitrogen heteroatoms onto the benzene ring of isoquinoline. This specifically lowers the energy level of the LUMO orbitals of the iridium complex molecule, effectively reducing the band gap between the HOMO and LUMO orbitals, thus achieving a redshift in the emission of the complex. Simultaneously, the molecule is modified by using nitrogen heteroatoms rather than expanding the conjugation scale or introducing additional substitutions, resulting in a simpler molecular structure. Its relative molecular mass is comparable to that of common red-emitting iridium complexes, ensuring the sublimation performance of the material and making it suitable for vacuum evaporation processes. In the structural design of the coordinating carbon end of the compound of this invention, rigid and relatively electron-rich groups are used, preferably including but not limited to thiophene, benzothiophene, dithiophene, N-phenyl-2-carbazolyl, dibenzofuran, and naphthyl groups, effectively raising the HOMO energy level of the complex, reducing the optical band gap, and further redshifting the emission.

[0047] Existing literature and patents report that most near-infrared luminescent iridium complexes have emission peaks below 750 nm, with many even around 700 nm. Considering the peak broadening of iridium complex emission, near-infrared luminescent iridium complexes with emission peaks below 750 nm exhibit visible red residual emission, limiting the material's technological applications. Compared to existing iridium complexes with substituted or unsubstituted phenyl or substituted or unsubstituted pyridyl groups at the ligand coordination carbon terminus, the carbon terminus used in the iridium metal complex of this invention has a significantly stronger electron-donating ability, contributing more to the HOMOs orbitals of the complex molecule and effectively raising the HOMOs energy level. This allows for pure near-infrared emission with emission peaks above 780 nm when combined with pyrido[3,4-b]pyrazine, with the overall emission peak above 700 nm.

[0048] Meanwhile, in the iridium metal complex of the present invention, the coordinated nitrogen-terminal backbone is controlled to consist of two fused aromatic rings, avoiding the problem of decreased contribution of metallic iridium in HOMOs due to the expansion of ligand conjugation in highly conjugated ligands. This maintains a high proportion of inter-ligand charge transfer (MLCT) components in the triplet state of phosphorescent emission, and the complex maintains a high radiative transition rate while exhibiting a redshift in emission. Furthermore, the rigid structure of the ligands effectively controls the geometric isomerization of the iridium metal complex of the present invention and restricts rotation within the complex molecule, controlling the non-radiative transition rate and improving the luminescence efficiency of the iridium metal complex of the present invention. Simultaneously, the protection of the octahedral three-dimensional coordination structure and the ligand periphery structure can also reduce the quenching of triplet excitons in OLED devices, ensuring that the iridium metal complex of the present invention does not suffer from efficiency roll-off at high current densities when used for luminescence.

[0049] Furthermore, in the iridium metal complex of the present invention, the preferred substitution site of the substituent R designed on the pyrazine ring is located in the direction of the Ir-N bond axis of the coordination bond, which is consistent with the direction of the triplet transition dipole moment of such iridium complexes. This is beneficial to the horizontal dipole orientation of the complex molecule in the light-emitting device, thereby significantly improving the light extraction efficiency of the device and the final external quantum efficiency of the device.

[0050] Furthermore, the compounds described in the general formula of this invention can preferably include the following specific structural compounds, which are merely representative. The numbering design rule for these representative specific compounds is as follows: the prefix C represents a compound; the following letters represent the coordinating carbon terminus: T represents thiophene, BT represents benzothiophene, TT represents thieno[3,2-b]thiophene, CZ represents N-phenyl-2-carbazolyl, BF represents dibenzofuran, and NP represents 4-tert-butyl-2-naphthyl.

[0051]

[0052]

[0053]

[0054]

[0055]

[0056]

[0057]

[0058]

[0059]

[0060] Another aspect of the present invention provides the use of the above-described iridium metal complex in an organic electroluminescent device. Specifically, its use as a light-emitting functional layer material in an organic electroluminescent device is preferred. It is more preferably used as a material in the light-emitting layer of the light-emitting functional layer, and most preferably as a light-emitting material in the light-emitting layer.

[0061] In another aspect, the present invention provides an organic electroluminescent device comprising a first electrode, a second electrode, and one or more light-emitting functional layers located between the first electrode and the second electrode, wherein the organic layer contains an iridium metal complex represented by formula (1) of the present invention.

[0062] Specifically, one embodiment of the present invention provides an organic electroluminescent device, including a substrate, and a first electrode, a plurality of light-emitting functional layers, and a second electrode sequentially formed on the substrate; the light-emitting functional layers include a hole transport region, a light-emitting layer, and an electron transport region, wherein the hole transport region is formed on the anode layer, the cathode layer is formed on the electron transport region, and the light-emitting layer is located between the hole transport region and the electron transport region; wherein the light-emitting layer contains compounds represented by the various general formulas described above, or contains compounds represented by the various specific structural formulas described above. Preferably, the compounds represented by the various general formulas of the present invention, or containing compounds represented by the various specific structural formulas described above, can be used as light-emitting dyes in the light-emitting layer.

[0063] The iridium metal complex of the present invention exhibits excellent performance when used in organic electroluminescent devices, and the reasons for this are presumed to be as follows:

[0064] First, in the iridium metal complex of the present invention, the L ligand adopts the pyrido[3,4-b]pyrazine ligand, which is a small conjugated system of electron-withdrawing nitrogen heteroatoms. While maintaining the contribution of metal iridium to the charge transfer between metal ligands in the frontier orbitals HOMOs, the energy level of LUMOs is specifically reduced, and the band gap between the molecular HOMO orbitals and LUMO orbitals is significantly reduced. This results in the iridium metal complex having a high MLCT component and a significant redshift in wavelength, thus enabling it to be used as a near-infrared luminescent material.

[0065] Secondly, compared with the compounds reported in the prior art that use substituted or unsubstituted phenyl / pyridyl groups as coordinating carbon ends, the iridium metal complex of the present invention has a more electron-rich carbon end, which causes a very significant red shift in the emission wavelength. It can achieve pure near-infrared emission and has higher irradiance and external quantum efficiency.

[0066] Third, in the iridium metal complex of the present invention, the L ligand has a rigid structure, which can effectively control the geometric isomerization of the iridium metal complex and restrict the rotation within the iridium metal complex molecule, improve the luminous efficiency of the iridium metal complex, and also reduce the quenching between triplet excitons in the iridium metal complex, thus overcoming the problem of efficiency roll-off of organic electroluminescent devices containing the iridium metal complex at high current densities.

[0067] Fourth, in the iridium metal complex of the present invention, the direction of the Ir-N bond axis of the substitution on the pyrazine ring of the L ligand is consistent with the direction of the triplet transition dipole moment of this type of iridium complex. This is beneficial to the horizontal dipole orientation of the complex molecule in the light-emitting device, which can significantly improve the light extraction efficiency of the device and improve the final external quantum efficiency of the device.

[0068] Fifth, the iridium metal complex of the present invention employs a heterocoordinate complex structure with two main ligands and one auxiliary ligand. The auxiliary ligand can be an aliphatic acetylacetone derivative or a more electron-rich nitrogen-containing auxiliary ligand. Increasing the electron-richness of the auxiliary ligand can raise the occupied orbital energy level of the iridium metal center. On the one hand, this can reduce the emission bandgap, causing a redshift in emission; on the other hand, it can reduce the energy difference between the occupied orbital energy levels of the iridium metal center and the ligand portion, promoting indirect spin-orbit coupling in the iridium complex, increasing the radiative transition rate, improving the luminescence efficiency of the iridium complex, and ultimately improving the external quantum efficiency of the device.

[0069] Sixth, in the iridium metal complex of the present invention, the main ligand L is deuterated. The main ligand L plays a role in the distribution of frontier orbitals in the complex, directly affecting the radiative and nonradiative luminescence rates. The high-frequency vibration of the CH bond in the deuterated main ligand L is transformed into CD bond vibration with a significantly reduced frequency, reducing the nonradiative loss caused by CH bond vibrational coupling, lowering the nonradiative luminescence rate of the complex, improving the luminescence efficiency of the complex, and ultimately improving the external quantum efficiency of the device.

[0070] OLED devices prepared using the iridium metal complex of this invention have higher luminous efficiency and better lifespan, which can meet the current requirements of panel manufacturers for high-performance materials and show good application prospects. Attached Figure Description

[0071] Figure 1 This is a device structure diagram of the electroluminescent device prepared by the iridium metal complex of the present invention;

[0072] Wherein: 110-substrate, 120-anode, 130-hole injection transport layer, 140-organic light-emitting layer, 150-electron transport layer, 160-cathode;

[0073] Figure 2 The electroluminescence spectrum of the OLED-5 device prepared in Device Example 5 of the present invention is shown.

[0074] Figure 3 This is a voltage-current density diagram of the OLED-5 device prepared in Device Example 5 of the present invention;

[0075] Figure 4 This is a voltage-irradiance diagram of the OLED-5 device prepared in Device Example 5 of the present invention;

[0076] Figure 5 This is a current density-external quantum efficiency diagram of the OLED-5 device prepared in Example 5 of the present invention. Detailed Implementation

[0077] To enable those skilled in the art to better understand the present invention, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The technical effects of the present invention will become clearer and easier to understand from the following detailed description of the embodiments of the invention with reference to the accompanying drawings.

[0078] Compound synthesis implementation methods:

[0079] The specific preparation methods of the above-mentioned new compounds of the present invention will be described in detail below using several synthetic examples, but the preparation methods of the present invention are not limited to these synthetic examples.

[0080] The compounds synthesized using methods not mentioned in the embodiments of this invention are all commercially available raw material products. The solvents and reagents used in this invention, such as ethyl acetate, toluene, petroleum ether, etc., can all be purchased from the domestic chemical product market, for example, from Sinopharm Reagent Company, TCI Company, Shanghai Bid Pharmaceutical Company, Bailingwei Reagent Company, etc. Alternatively, those skilled in the art can synthesize them using well-known methods.

[0081] The synthesis method of the compounds of the present invention will be briefly described below.

[0082] Compound Synthesis Examples

[0083] Representative synthetic pathways:

[0084] (a) The synthesis of the main ligand L is required before the synthesis of the complex. The structure of the main ligand L has a modular feature:

[0085] The starting material for the synthesis of the main ligand is 3,4-diamino-2-chloropyridine.

[0086] (1) Combine with different o-dialdehyde or o-diketone hydrates to perform two-molecule dehydration condensation to form a ring:

[0087]

[0088] The specific synthesis method is as follows:

[0089] Under a nitrogen atmosphere, 3,4-diamino-2-chloropyridine and an equal amount of o-dialdehyde / benzoylcarboxaldehyde hydrate / 4-trifluoromethylbenzoylcarboxaldehyde hydrate / 4'-tert-butyl-4-phenylbenzoylcarboxaldehyde hydrate were dissolved in an appropriate amount of 1,4-dioxane. The mixture was stirred and heated under reflux for 6 hours. After cooling to room temperature, the solvent was removed by rotary evaporation and dried to obtain a reddish-brown solid. No further purification was required, and it was directly used as the chlorine substrate for the next step of the Suzuki / Stille reaction.

[0090] (2) Synthesize the host ligand L via the Suzuki / Stille coupling reaction:

[0091]

[0092] The specific synthesis method is as follows:

[0093] Suzuki's reaction:

[0094] Under a nitrogen atmosphere, 1 part of chlorine substrate, 1.2 parts of boric acid, 0.05 parts of tetraphenylphosphine palladium, and 3 parts of potassium carbonate were dissolved in an appropriate amount of 1,4-dioxane:water mixed solvent with a volume ratio of 3:1. The mixture was heated and stirred at 90°C for 24 hours. After the reaction was completed, the mixture was cooled to room temperature, filtered with diatomaceous earth, and washed with ethyl acetate. The organic phase was then separated by liquid chromatography, washed three times with saturated brine, dried over anhydrous magnesium sulfate, and purified by rotary evaporation using silica gel adsorption. The eluent was petroleum ether:ethyl acetate, with 2% triethylamine added to reduce the adsorption of the target product on the silica gel column. Molecules with substituents on opposite sides of the coordinating carbon terminus were less polar and eluted first, while molecules with substituents on the same side of the coordinating carbon terminus were more polar and eluted subsequently. The products were collected separately and the solvent was removed by rotary evaporation, yielding solid products ranging from yellow to pale green.

[0095] Stille reaction

[0096] Under a nitrogen atmosphere, 1 part of chlorine substrate, 1.2 parts of 2-thiophenetributyltin reagent, 0.05 parts of tetrakis(triphenylphosphine)palladium, and 3 parts of potassium fluoride were dissolved in an appropriate amount of 1,4-dioxane. The mixture was stirred and heated at 110°C for 48 hours. After the reaction was completed, the mixture was cooled to room temperature, filtered through diatomaceous earth, and washed with ethyl acetate. The solvent was removed by rotary evaporation using silica gel adsorption. The product was then purified by silica gel column chromatography using petroleum ether:ethyl acetate as the eluent, with 2% triethylamine added to reduce the adsorption of the target product on the silica gel column. Molecules with substituents on opposite sides of the coordinating carbon segment were less polar and eluted first, while molecules with substituents on the same side of the coordinating carbon segment were more polar and eluted subsequently. The molecules were collected separately and the solvent was removed by rotary evaporation to obtain a yellow solid product.

[0097] (ii) After obtaining the main ligand, the corresponding complex is synthesized.

[0098] (1) Synthesis of dichloro-bridged complexes:

[0099]

[0100] Synthesis method:

[0101] Under a nitrogen atmosphere, 1 part hydrated iridium trichloride and 2.2 parts of the main ligand were dissolved in an appropriate amount of a mixed solvent of ethylene glycol monomethyl ether and water in a volume ratio of 3:1, and the mixture was stirred at 110°C for 24 hours. After cooling to room temperature, a large amount of water was added, resulting in the formation of a black precipitate. The precipitate was filtered, washed with n-hexane, diethyl ether, and methanol, and then dried to obtain a black dichloro-bridged product.

[0102] (2) Synthesis of heterozygous complexes with β-diketone as the auxiliary ligand:

[0103]

[0104] Synthesis method:

[0105] Take 1 part of dichlorobridged substrate, 3 parts of acetylacetone or its derivative, and 3 parts of potassium tert-butoxide, and dissolve them in a dichloromethane:ethanol solvent with a volume ratio of 3:1. Stir the mixture at 30°C for 24 hours. After the reaction is complete and cooled, extract the organic phase with dichloromethane, wash with saturated brine, dry with anhydrous magnesium sulfate, concentrate, and purify by neutral alumina column chromatography to obtain a black solid product.

[0106] (3) Synthesize heterocohesive complexes with 4-(phenylimino)-2-pentanone as the auxiliary ligand.

[0107]

[0108] Synthesis method:

[0109] Under a nitrogen atmosphere, 4-(phenylimino)-2-pentanone was dissolved in a suitable amount of diethyl ether. The colorless solution was frozen in cold hydrazine. The freezing apparatus was removed, and one equivalent of solid potassium benzyl was added during melting to obtain a colorless suspension, which was stirred at room temperature for 1 hour. Volatiles were removed under vacuum, and the colorless solid was suspended in a suitable amount of pentane and cooled to -35°C. The cold mixture was filtered, the product was washed with pentane, and dried under vacuum to obtain the auxiliary ligand potassium salt.

[0110] Under a nitrogen atmosphere, one part of the dichloro-bridged substrate was suspended in an appropriate amount of tetrahydrofuran, and a tetrahydrofuran solution containing two parts of the aforementioned potassium salt was added. After stirring at room temperature for 2.5 hours, the solvent was removed by vacuum concentration, and the product was purified by neutral alumina column chromatography to obtain a black solid product.

[0111] (4) Synthesis of heterocoordinates with amidine as the auxiliary ligand:

[0112]

[0113] Synthesis method:

[0114] Under a nitrogen atmosphere, 0.31 mmol of bromobenzene was dissolved in 2 mL of tetrahydrofuran. Under liquid nitrogen cooling, 0.1 mL of a 2.5 mol / L n-butyllithium solution in n-hexane was added to the reaction mixture, and the mixture was stirred for 30 minutes. The resulting reaction mixture was then added dropwise to 0.31 mmol of N,N'-diisopropylcarbodiimide, and the mixture was reacted for another 30 minutes under liquid nitrogen cooling. The resulting reaction mixture was then added dropwise to a Teflon-sealed glass tube containing 0.079 mmol of a dichlorobridged complex and 5 mL of tetrahydrofuran. The mixture was stirred overnight at 80°C and then cooled to room temperature. After removing the volatile solvent by rotary evaporation, the crude solid product was dissolved in a minimal amount of tetrahydrofuran. n-Pentane was added dropwise to the solution, and a black solid precipitated. The product was then dissolved in a minimal amount of dichloromethane, and cyclohexane was added to precipitate the byproduct. The dichloromethane / n-hexane solution was then evaporated by rotary evaporation to obtain the black solid product.

[0115] (5) Synthesis of heterocomplexes with 8-hydroxyquinoline as the auxiliary ligand:

[0116]

[0117] Synthesis method:

[0118] Take 1 part of dichlorobridged substrate and 3.8 parts of 8-hydroxyquinoline, dissolve them in an appropriate amount of dichloromethane:ethanol:triethylamine solvent in a volume ratio of 2:2:1, and stir the reaction at 80 degrees Celsius for 16 hours. After the reaction is completed and cooled, remove the solvent by rotary evaporation, and purify the product by neutral alumina column chromatography to obtain a black solid product.

[0119] The following embodiments are further illustrations of the present invention and are not intended to limit the invention.

[0120] Example 1: Synthesis of 5-chloropyrido[3,4-b]pyrazine

[0121]

[0122] The specific synthesis method is as follows:

[0123] Under a nitrogen atmosphere, 3,4-diamino-2-chloropyridine and an equal amount of glyoxal were dissolved in an appropriate amount of 1,4-dioxane. The mixture was stirred and heated under reflux for 6 hours. After cooling to room temperature, the solvent was removed by rotary evaporation and dried to obtain a reddish-brown solid. No further purification was required, and it was directly used as the chlorine substrate for the subsequent coupling reaction.

[0124] ESI-HRMS (High-resolution electrospray ionization mass spectrometry) [m / z]: 166.02 [M+H] + .

[0125] Example 2: Synthesis of 5-chloro-2-phenylpyrido[3,4-b]pyrazine and 5-chloro-3-phenylpyrido[3,4-b]pyrazine

[0126]

[0127] The specific synthesis method is as follows:

[0128] Under a nitrogen atmosphere, 3,4-diamino-2-chloropyridine and an equal amount of benzoyl formaldehyde hydrate were dissolved in an appropriate amount of 1,4-dioxane. The mixture was stirred and heated under reflux for 6 hours. After cooling to room temperature, the solvent was removed by rotary evaporation and dried to obtain a reddish-brown solid. No further purification was required, and it was directly used as the chlorine substrate for the subsequent coupling reaction.

[0129] ESI-HRMS (High-resolution electrospray ionization mass spectrometry) [m / z]: 242.05 [M+H] + .

[0130] Example 3: Synthesis of 5-chloro-2-(4-trifluoromethylphenyl)pyrido[3,4-b]pyrazine and 5-chloro-3-(4-trifluoromethylphenyl)pyrido[3,4-b]pyrazine

[0131]

[0132] The specific synthesis method is as follows:

[0133] Under a nitrogen atmosphere, 3,4-diamino-2-chloropyridine and an equal amount of 4-trifluoromethylbenzoyl aldehyde hydrate were dissolved in an appropriate amount of 1,4-dioxane. The mixture was stirred and heated under reflux for 6 hours. After cooling to room temperature, the solvent was removed by rotary evaporation and dried to obtain a reddish-brown solid. No further purification was required, and it was directly used as the chlorine substrate for the subsequent coupling reaction.

[0134] ESI-HRMS (High-resolution electrospray ionization mass spectrometry) [m / z]: 310.04 [M+H] + .

[0135] Example 4: Synthesis of 5-chloro-2-(4'-tert-butyl-4-phenylphenyl)pyrido[3,4-b]pyrazine and 5-chloro-3-(4'-tert-butyl-4-phenylphenyl)pyrido[3,4-b]pyrazine

[0136]

[0137] The specific synthesis method is as follows:

[0138] Under a nitrogen atmosphere, 3,4-diamino-2-chloropyridine and an equal amount of 4'-tert-butyl-4-phenylbenzoyl aldehyde hydrate were dissolved in an appropriate amount of 1,4-dioxane. The mixture was stirred and heated under reflux for 6 hours. After cooling to room temperature, the solvent was removed by rotary evaporation and dried to obtain a reddish-brown solid. No further purification was required, and it was directly used as the chlorine substrate for the subsequent coupling reaction.

[0139] ESI-HRMS (High-resolution electrospray ionization mass spectrometry) [m / z]: 374.14 [M+H] + .

[0140] Example 5: Synthesis of 5-(2-thienyl)pyrido[3,4-b]pyrazine

[0141]

[0142] Under a nitrogen atmosphere, 1 part of 5-chloropyrido[3,4-b]pyrazine, 1.2 parts of 2-thiophene tributyltin reagent, 0.05 parts of tetrakis(triphenylphosphine)palladium, and 3 parts of potassium fluoride were dissolved in an appropriate amount of 1,4-dioxane, and the mixture was stirred and heated at 110°C for 48 hours. After the reaction was completed, the mixture was cooled to room temperature, filtered through diatomaceous earth, and washed with ethyl acetate. The solvent was removed by rotary evaporation using silica gel adsorption, and the product was purified by silica gel column chromatography with petroleum ether:ethyl acetate as the eluent. 2% triethylamine was added to reduce the adsorption of the target product on the silica gel column. The solvent was collected and removed by rotary evaporation to give a yellow solid product with a yield of 72%.

[0143] ESI-HRMS (High-resolution electrospray ionization mass spectrometry) [m / z]: 214.04 [M+H] + .

[0144] Elemental analysis (C 11 H7N3S):

[0145] Anal.Calcd (theoretical values): C, 61.95; H, 3.31; N, 19.70; S, 15.03;

[0146] Found (measured values): C, 61.92; H, 3.31; N, 19.72; S, 15.04.

[0147] Example 6: Synthesis of 5-(2-benzothienyl)pyrido[3,4-b]pyrazine

[0148]

[0149] Under a nitrogen atmosphere, 1 part of 5-chloropyrido[3,4-b]pyrazine, 1.2 parts of 2-benzothiophene boric acid, 0.05 parts of tetraphenylphosphine palladium, and 3 parts of potassium carbonate were dissolved in an appropriate amount of 1,4-dioxane:water mixed solvent with a volume ratio of 3:1. The mixture was heated and stirred at 90°C for 24 hours. After the reaction was completed, the mixture was cooled to room temperature, filtered with diatomaceous earth, and washed with ethyl acetate. The organic phase was then separated by liquid chromatography, washed three times with saturated brine, dried over anhydrous magnesium sulfate, and purified by rotary evaporation using silica gel adsorption. The eluent was petroleum ether:ethyl acetate, with 2% triethylamine added to reduce the adsorption of the target product on the silica gel column. The solvent was removed by rotary evaporation, yielding a yellow solid product with a yield of 71%.

[0150] ESI-HRMS (High-resolution electrospray ionization mass spectrometry) [m / z]: 264.06 [M+H] + .

[0151] Elemental analysis (C 15 H9N3S):

[0152] Anal.Calcd (theoretical values): C, 68.42; H, 3.45; N, 15.96; S, 12.18;

[0153] Found (measured values): C, 68.43; H, 3.43; N, 15.96; S, 12.19.

[0154] Example 7: Synthesis of 5-(2-thienothienyl)pyrido[3,4-b]pyrazine

[0155]

[0156] Under a nitrogen atmosphere, 1 part of 5-chloropyrido[3,4-b]pyrazine, 1.2 parts of 2-thiophenothiophene boric acid, 0.05 parts of tetraphenylphosphine palladium, and 3 parts of potassium carbonate were dissolved in a suitable amount of 1,4-dioxane:water mixed solvent with a volume ratio of 3:1. The mixture was heated and stirred at 90°C for 24 hours. After the reaction was completed, the mixture was cooled to room temperature, filtered with diatomaceous earth, and washed with ethyl acetate. The organic phase was then separated by liquid chromatography, washed three times with saturated brine, dried over anhydrous magnesium sulfate, and purified by rotary evaporation using silica gel adsorption. The eluent was petroleum ether:ethyl acetate, with 2% triethylamine added to reduce the adsorption of the target product on the silica gel column. The solvent was removed by rotary evaporation, yielding a yellow solid product with a yield of 61%.

[0157] ESI-HRMS (High-resolution electrospray ionization mass spectrometry) [m / z]: 270.02 [M+H] + .

[0158] Elemental analysis (C 13 H7N3S2):

[0159] Anal.Calcd (theoretical values): C, 57.97; H, 2.62; N, 15.60; S, 23.81;

[0160] Found (measured values): C, 57.98; H, 2.63; N, 15.59; S, 23.80.

[0161] Example 8: Synthesis of 5-(9-phenylcarbazole)-2-ylpyridino[3,4-b]pyrazine

[0162]

[0163] Under a nitrogen atmosphere, 1 part of 5-chloropyrido[3,4-b]pyrazine, 1.2 parts of 9-phenyl-2-carbazoleboric acid, 0.05 parts of tetraphenylphosphine palladium, and 3 parts of potassium carbonate were dissolved in a suitable amount of 1,4-dioxane:water mixed solvent with a volume ratio of 3:1. The mixture was heated and stirred at 90°C for 24 hours. After the reaction was completed, the mixture was cooled to room temperature, filtered with diatomaceous earth, and washed with ethyl acetate. The organic phase was then separated by liquid chromatography, washed three times with saturated brine, dried over anhydrous magnesium sulfate, and purified by rotary evaporation using silica gel adsorption. The eluent was petroleum ether:ethyl acetate, with 2% triethylamine added to reduce the adsorption of the target product on the silica gel column. The solvent was removed by rotary evaporation, yielding a pale green solid product in 59% yield.

[0164] ESI-HRMS (High-resolution electrospray ionization mass spectrometry) [m / z]: 373.15 [M+H] + .

[0165] Elemental analysis (C 25 H 16 N4):

[0166] Anal.Calcd (theoretical values): C, 80.63; H, 4.33; N, 15.04;

[0167] Found (measured values): C, 80.65; H, 4.32; N, 15.03.

[0168] Example 9: Synthesis of 5-dibenzofuran-2-ylpyridino[3,4-b]pyrazine

[0169]

[0170] Under a nitrogen atmosphere, 1 part of 5-chloropyridino[3,4-b]pyrazine, 1.2 parts of dibenzofuran-2-boric acid, 0.05 parts of tetraphenylphosphine palladium, and 3 parts of potassium carbonate were dissolved in a suitable amount of 1,4-dioxane:water mixed solvent with a volume ratio of 3:1. The mixture was heated and stirred at 90°C for 24 hours. After the reaction was completed, the mixture was cooled to room temperature, filtered with diatomaceous earth, and washed with ethyl acetate. The organic phase was then separated by liquid chromatography, washed three times with saturated brine, dried over anhydrous magnesium sulfate, and purified by rotary evaporation using silica gel adsorption. The eluent was petroleum ether:ethyl acetate, with 2% triethylamine added to reduce the adsorption of the target product on the silica gel column. The solvent was removed by rotary evaporation after collection, yielding a pale green solid product with a yield of 72%.

[0171] ESI-HRMS (High-resolution electrospray ionization mass spectrometry) [m / z]: 298.10 [M+H] + .

[0172] Elemental analysis (C 19 H11 N3O):

[0173] Anal.Calcd (theoretical values): C, 76.76; H, 3.73; N, 14.13; O, 5.38;

[0174] Found (measured values): C, 76.77; H, 3.74; N, 14.12; O, 5.37.

[0175] Example 10: Synthesis of 2-phenyl-5-(2-thienyl)pyrido[3,4-b]pyrazine and 3-phenyl-5-(2-thienyl)pyrido[3,4-b]pyrazine

[0176]

[0177] Under a nitrogen atmosphere, 1 part of a mixture of 2-phenyl-5-chloropyrido[3,4-b]pyrazine and 3-phenyl-5-chloropyrido[3,4-b]pyrazine, 1.2 parts of 2-thiophene tributyltin reagent, 0.05 parts of tetrakis(triphenylphosphine)palladium, and 3 parts of potassium fluoride were dissolved in an appropriate amount of 1,4-dioxane. The mixture was stirred and heated at 110°C for 48 hours. After the reaction was completed, the mixture was cooled to room temperature, filtered with diatomaceous earth, and washed with ethyl acetate. The solvent was removed by rotary evaporation using silica gel adsorption, and the product was purified by silica gel column chromatography. The eluent was petroleum ether:ethyl acetate, and 2% triethylamine was added to reduce the adsorption of the target product on the silica gel column. 2-Phenylacetylpyrido[3,4-b]pyrazine, being less polar, was eluted first, while 3-Phenylacetylpyrido[3,4-b]pyrazine, being more polar, was eluted subsequently. Both were collected and the solvent was removed by rotary evaporation to give yellow solid products, with the former yielding 47% and the latter yielding 22%.

[0178] ESI-HRMS (High-resolution electrospray ionization mass spectrometry) [m / z]: 290.08 [M+H] + .

[0179] Elemental analysis (C 17 H 11 N3S):

[0180] Anal.Calcd (theoretical values): C, 70.57; H, 3.83; N, 14.52; S, 11.08;

[0181] Found (measured values): C, 70.55; H, 3.84; N, 14.51; S, 11.10.

[0182] Example 11: Synthesis of 2-(4-trifluoromethylphenyl)-5-(2-benzothienyl)pyrido[3,4-b]pyrazine and 3-(4-trifluoromethylphenyl)-5-(2-benzothienyl)pyrido[3,4-b]pyrazine

[0183]

[0184] Under a nitrogen atmosphere, 1 part of a mixture of 2-(4-trifluoromethylphenyl)-5-chloropyrido[3,4-b]pyrazine and 3-(4-trifluoromethylphenyl)-5-chloropyrido[3,4-b]pyrazine, 1.2 parts of 2-benzothiophene boric acid, 0.05 parts of tetraphenylphosphine palladium, and 3 parts of potassium carbonate were dissolved in an appropriate amount of 1,4-dioxane:water mixed solvent with a volume ratio of 3:1. The mixture was heated and stirred at 90°C for 24 hours. After the reaction was completed, the mixture was cooled to room temperature, filtered with diatomaceous earth, and washed with ethyl acetate. The organic phase was then separated by liquid chromatography, washed three times with saturated brine, dried over anhydrous magnesium sulfate, and purified by rotary evaporation using silica gel adsorption. The eluent was petroleum ether:ethyl acetate, with 2% triethylamine added to reduce the adsorption of the target product on the silica gel column. 2-(4-trifluoromethylphenyl)-5-(2-benzothienyl)pyrido[3,4-b]pyrazine, being less polar, was eluted first, while 3-(4-trifluoromethylphenyl)-5-(2-benzothienyl)pyrido[3,4-b]pyrazine, being more polar, was eluted subsequently. The solvents were removed by rotary evaporation from each product, yielding yellow solids. The former had a yield of 42%, and the latter a yield of 20%.

[0185] ESI-HRMS (High-resolution electrospray ionization mass spectrometry) [m / z]: 408.08 [M+H] + .

[0186] Elemental analysis (C 22 H 12 F3N3S):

[0187] Anal.Calcd (theoretical values): C, 64.86; H, 2.97; N, 10.31; S, 7.87;

[0188] Found (measured values): C, 64.85; H, 2.98; N, 10.30; S, 7.88.

[0189] Example 12: Synthesis of 2-(4'-tert-butyl-4-phenylphenyl)-5-(2-thienothienoyl)pyrido[3,4-b]pyrazine and 3-(4'-tert-butyl-4-phenylphenyl)-5-(2-thienothienoyl)pyrido[3,4-b]pyrazine

[0190]

[0191] Under a nitrogen atmosphere, 1 part of a mixture of 2-(4'-tert-butyl-4-phenylphenyl)-5-chloropyrido[3,4-b]pyrazine and 3-(4'-tert-butyl-4-phenylphenyl)-5-(2-thienothienoyl)pyrido[3,4-b]pyrazine, 1.2 parts of 2-thienothienoboric acid, 0.05 parts of tetraphenylphosphine palladium, and 3 parts of potassium carbonate were dissolved in an appropriate amount of 1,4-dioxane:water mixed solvent with a volume ratio of 3:1. The mixture was heated and stirred at 90°C for 24 hours. After the reaction was completed, the mixture was cooled to room temperature, filtered with diatomaceous earth, and washed with ethyl acetate. The organic phase was then separated by liquid chromatography, washed three times with saturated brine, dried over anhydrous magnesium sulfate, and purified by rotary evaporation using silica gel adsorption. The eluent was petroleum ether:ethyl acetate, with 2% triethylamine added to reduce the adsorption of the target product on the silica gel column. 2-(4'-tert-butyl-4-phenylphenyl)-5-(2-thienothienoyl)pyrido[3,4-b]pyrazine, being less polar, was eluted first, while 3-(4'-tert-butyl-4-phenylphenyl)-5-(2-thienothienoyl)pyrido[3,4-b]pyrazine, being more polar, was eluted subsequently. Both were collected and the solvent was removed by rotary evaporation to give yellow solid products, with the former yielding 39% and the latter yielding 18%.

[0192] ESI-HRMS (High-resolution electrospray ionization mass spectrometry) [m / z]: 478.14 [M+H] + .

[0193] Elemental analysis (C 29 H 23 N3S2):

[0194] Anal.Calcd (theoretical values): C, 72.92; H, 4.85; N, 8.80; S, 13.42;

[0195] Found (measured values): C, 72.91; H, 4.84; N, 8.81; S, 13.41.

[0196] Example 13: Synthesis of deuterated 5-(2-benzothienyl)pyrido[3,4-b]pyrazine

[0197]

[0198] The Teflon liner of the reaction vessel was removed, and 1 part of 5-(2-benzothienyl)pyrido[3,4-b]pyrazine, 0.05 parts of platinum dioxide, and excess heavy water (7.5 mL of heavy water per 1 mmol of ligand substrate) were added. The reaction vessel was sealed and placed in a furnace at 250°C for 14 hours. After the reaction was stopped, it was completely cooled to room temperature. The resulting reaction solution was extracted with chloroform, and the Teflon liner was sonicated with chloroform. The resulting organic phases were combined, dried over anhydrous sodium sulfate, and the solvent was removed by rotary evaporation. The product was purified by silica gel column chromatography to obtain a yellow solid product in 83% yield.

[0199] ESI-HRMS (High-resolution electrospray ionization mass spectrometry) [m / z]: 273.12 [M+H] + .

[0200] Elemental analysis (C 15 D9N3S):

[0201] Anal.Calcd (theoretical values): C, 66.15; D, 6.66; N, 15.43; S, 11.77;

[0202] Found (measured values): C, 66.13; D, 6.67; N, 15.42; S, 11.79.

[0203] Example 14: Synthesis of deuterated 5-(2-thienothienyl)pyrido[3,4-b]pyrazine

[0204]

[0205] The Teflon liner of the reaction vessel was removed, and 1 part of 5-(2-thienothienoyl)pyrido[3,4-b]pyrazine, 0.05 parts of platinum dioxide, and excess heavy water (7.5 mL of heavy water per 1 mmol of ligand substrate) were added. The reaction vessel was sealed and placed in a furnace at 250°C for 14 hours. After the reaction was stopped, it was completely cooled to room temperature. The resulting reaction solution was extracted with chloroform, and the Teflon liner was sonicated with chloroform. The resulting organic phases were combined, dried over anhydrous sodium sulfate, and the solvent was removed by rotary evaporation. The product was purified by silica gel column chromatography to obtain a yellow solid product in 79% yield.

[0206] ESI-HRMS (High-resolution electrospray ionization mass spectrometry) [m / z]: 277.06 [M+H] + .

[0207] Elemental analysis (C 13 D7N3S2):

[0208] Anal.Calcd (theoretical values): C, 56.50; D, 5.10; N, 15.20; S, 23.20;

[0209] Found (measured values): C, 56.51; D, 5.10; N, 15.19; S, 23.20.

[0210] Example 15: Synthesis of deuterated 2-phenyl-5-(2-thienyl)pyrido[3,4-b]pyrazine

[0211]

[0212] The Teflon liner of the reaction vessel was removed, and 1 part of 2-phenyl-5-(2-thienyl)pyrido[3,4-b]pyrazine, 0.05 parts of platinum dioxide, and excess heavy water (7.5 mL of heavy water per 1 mmol of ligand substrate) were added. The reaction vessel was sealed and placed in a furnace at 250°C for 14 hours. After the reaction was stopped, it was completely cooled to room temperature. The resulting reaction solution was extracted with chloroform, and the Teflon liner was sonicated with chloroform. The resulting organic phases were combined, dried over anhydrous sodium sulfate, and the solvent was removed by rotary evaporation. The product was purified by silica gel column chromatography to obtain a yellow solid product in 73% yield.

[0213] ESI-HRMS (High-resolution electrospray ionization mass spectrometry) [m / z]: 301.14 [M+H] + .

[0214] Elemental analysis (C 17 D 11 N3S):

[0215] Anal.Calcd (theoretical values): C, 67.97; D, 7.37; N, 13.99; S, 10.67;

[0216] Found (measured values): C, 67.99; D, 7.35; N, 13.98; S, 10.68.

[0217] Example 16: Synthesis of dichlorobridged intermediates corresponding to CT1,5,9,13,17,21

[0218]

[0219] Synthesis method:

[0220] Under a nitrogen atmosphere, 1 part iridium trichloride hydrate and 2.2 parts 5-(2-thienyl)pyridino[3,4-b]pyrazine were dissolved in a suitable amount of ethylene glycol monomethyl ether:water mixed solvent with a volume ratio of 3:1. The mixture was stirred at 110°C for 24 hours. After cooling to room temperature, a large amount of water was added, resulting in the formation of a black precipitate. The precipitate was filtered, washed with n-hexane, diethyl ether, and methanol, and dried to obtain a black dichloro-bridged product. No further purification was required, and it was directly used as a substrate for subsequent auxiliary ligand reactions.

[0221] ESI-HRMS (High-resolution electrospray ionization mass spectrometry) [m / z]: 617.02 [1 / 2M-Cl] - ] + .

[0222] Example 17: Synthesis of dichlorobridged intermediates corresponding to CBT1,5,9,13,17,21

[0223]

[0224] Synthesis method:

[0225] Under a nitrogen atmosphere, 1 part iridium trichloride hydrate and 2.2 parts 5-(2-benzothiophene)pyrido[3,4-b]pyrazine were dissolved in a suitable amount of ethylene glycol monomethyl ether:water mixed solvent with a volume ratio of 3:1. The mixture was stirred at 110°C for 24 hours. After cooling to room temperature, a large amount of water was added, resulting in the formation of a black precipitate. The precipitate was filtered, washed with n-hexane, diethyl ether, and methanol, and dried to obtain a black dichloro-bridged product. No further purification was required, and this product was used directly as a substrate for subsequent auxiliary ligand reactions.

[0226] ESI-HRMS (High-resolution electrospray ionization mass spectrometry) [m / z]: 717.05 [1 / 2M-Cl] - ] + .

[0227] Example 18: Synthesis of dichlorobridged intermediates corresponding to CTT1,5,9,13,17,21

[0228]

[0229] Synthesis method:

[0230] Under a nitrogen atmosphere, 1 part iridium trichloride hydrate and 2.2 parts 5-(2-thienothienoyl)pyridino[3,4-b]pyrazine were dissolved in a suitable amount of ethylene glycol monomethyl ether:water mixed solvent with a volume ratio of 3:1. The mixture was stirred at 110°C for 24 hours. After cooling to room temperature, a large amount of water was added, resulting in the formation of a black precipitate. The precipitate was filtered, washed with n-hexane, diethyl ether, and methanol, and dried to obtain a black dichloro-bridged product. No further purification was required, and this product was used directly as a substrate for subsequent auxiliary ligand reactions.

[0231] ESI-HRMS (High-resolution electrospray ionization mass spectrometry) [m / z]: 728.96 [1 / 2M-Cl] - ] + .

[0232] Example 19: Synthesis of dichlorobridged intermediates corresponding to CCZ1,5,9,13,17,21

[0233]

[0234] Synthesis method:

[0235] Under a nitrogen atmosphere, 1 part iridium trichloride hydrate and 2.2 parts 5-(9-phenylcarbazole)-2-ylpyridino[3,4-b]pyrazine were dissolved in an appropriate amount of ethylene glycol monomethyl ether:water mixed solvent with a volume ratio of 3:1. The mixture was stirred at 110°C for 24 hours. After cooling to room temperature, a large amount of water was added, resulting in the formation of a black precipitate. The precipitate was filtered, washed with n-hexane, diethyl ether, and methanol, and dried to obtain a black dichloro-bridged product. No further purification was required, and this product was used directly as a substrate for subsequent auxiliary ligand reactions.

[0236] ESI-HRMS (High-resolution electrospray ionization mass spectrometry) [m / z]: 935.22 [1 / 2M-Cl] - ] + .

[0237] Example 20: Synthesis of dichlorobridged intermediates corresponding to CBF1,5,9,13,17,21

[0238]

[0239] Synthesis method:

[0240] Under a nitrogen atmosphere, 1 part iridium trichloride hydrate and 2.2 parts 5-dibenzofuran-2-ylpyridino[3,4-b]pyrazine were dissolved in an appropriate amount of ethylene glycol monomethyl ether:water mixed solvent with a volume ratio of 3:1. The mixture was stirred at 110°C for 24 hours. After cooling to room temperature, a large amount of water was added, resulting in the formation of a black precipitate. The precipitate was filtered, washed with n-hexane, diethyl ether, and methanol, and dried to obtain a black dichloro-bridged product. No further purification was required, and this product was used directly as a substrate for subsequent auxiliary ligand reactions.

[0241] ESI-HRMS (High-resolution electrospray ionization mass spectrometry) [m / z]: 785.13 [1 / 2M-Cl] - ] + .

[0242] Example 21: Synthesis of dichlorobridged intermediates corresponding to CT2,6,10,14,18,22

[0243]

[0244] Synthesis method:

[0245] Under a nitrogen atmosphere, 1 part iridium trichloride hydrate and 2.2 parts 2-phenyl-5-(2-thienyl)pyridino[3,4-b]pyrazine were dissolved in a suitable amount of ethylene glycol monomethyl ether:water mixed solvent with a volume ratio of 3:1. The mixture was stirred at 110°C for 24 hours. After cooling to room temperature, a large amount of water was added, resulting in the formation of a black precipitate. The precipitate was filtered, washed with n-hexane, diethyl ether, and methanol, and dried to obtain a black dichloro-bridged product. No further purification was required, and it was directly used as a substrate for subsequent auxiliary ligand reactions.

[0246] ESI-HRMS (High-resolution electrospray ionization mass spectrometry) [m / z]: 769.08 [1 / 2M-Cl] - ] + .

[0247] Example 22: Synthesis of dichlorobridged intermediates corresponding to CT27,30

[0248]

[0249] Synthesis method:

[0250] Under a nitrogen atmosphere, 1 part iridium trichloride hydrate and 2.2 parts 3-phenyl-5-(2-thienyl)pyridino[3,4-b]pyrazine were dissolved in a suitable amount of ethylene glycol monomethyl ether:water mixed solvent with a volume ratio of 3:1. The mixture was stirred at 110°C for 24 hours. After cooling to room temperature, a large amount of water was added, resulting in the formation of a black precipitate. The precipitate was filtered, washed with n-hexane, diethyl ether, and methanol, and dried to obtain a black dichloro-bridged product. No further purification was required, and this product was used directly as a substrate for subsequent auxiliary ligand reactions.

[0251] ESI-HRMS (High-resolution electrospray ionization mass spectrometry) [m / z]: 769.08 [1 / 2M-Cl] - ] + .

[0252] Example 23: Synthesis of dichlorobridged intermediates corresponding to CBT3,7,11,15,19,23

[0253]

[0254] Synthesis method:

[0255] Under a nitrogen atmosphere, 1 part iridium trichloride hydrate and 2.2 parts 2-(4-trifluoromethylphenyl)-5-(2-benzothiophene)pyrido[3,4-b]pyrazine were dissolved in a suitable volume ratio of ethylene glycol monomethyl ether:water mixed solvent of 3:1. The mixture was stirred at 110°C for 24 hours. After cooling to room temperature, a large amount of water was added, resulting in the formation of a black precipitate. The precipitate was filtered, washed with n-hexane, diethyl ether, and methanol, and dried to obtain a black dichloro-bridged product. No further purification was required, and this product was used directly as a substrate for subsequent auxiliary ligand reactions.

[0256] ESI-HRMS (High-resolution electrospray ionization mass spectrometry) [m / z]: 1005.09 [1 / 2M-Cl] - ] + .

[0257] Example 24: Synthesis of dichlorobridged intermediates corresponding to CBT28,31

[0258]

[0259] Synthesis method:

[0260] Under a nitrogen atmosphere, 1 part iridium trichloride hydrate and 2.2 parts 3-(4-trifluoromethylphenyl)-5-(2-benzothiophene)pyrido[3,4-b]pyrazine were dissolved in a suitable volume ratio of ethylene glycol monomethyl ether:water. The mixture was stirred at 110°C for 24 hours. After cooling to room temperature, a large amount of water was added, resulting in the formation of a black precipitate. The precipitate was filtered, washed with n-hexane, diethyl ether, and methanol, and dried to obtain a black dichloro-bridged product. This product, without further purification, was used directly as a substrate for subsequent auxiliary ligand reactions.

[0261] ESI-HRMS (High-resolution electrospray ionization mass spectrometry) [m / z]: 1005.09 [1 / 2M-Cl] - ] + .

[0262] Example 25: Synthesis of dichlorobridged intermediates corresponding to CTT4,8,12,16,20,24

[0263]

[0264] Synthesis method:

[0265] Under a nitrogen atmosphere, 1 part iridium trichloride hydrate and 2.2 parts 2-(4'-tert-butyl-4-phenylphenyl)-5-(2-thienothienoyl)pyridino[3,4-b]pyrazine were dissolved in a suitable amount of ethylene glycol monomethyl ether:water mixed solvent with a volume ratio of 3:1. The mixture was stirred at 110°C for 24 hours. After cooling to room temperature, a large amount of water was added, resulting in the formation of a black precipitate. The precipitate was filtered, washed with n-hexane, diethyl ether, and methanol, and dried to obtain a black dichloro-bridged product. No further purification was required, and this product was used directly as a substrate for subsequent auxiliary ligand reactions.

[0266] ESI-HRMS (High-resolution electrospray ionization mass spectrometry) [m / z]: 1145.21 [1 / 2M-Cl] - ] + .

[0267] Example 26: Synthesis of the dichlorobridged intermediate corresponding to CBT25

[0268]

[0269] Synthesis method:

[0270] Under a nitrogen atmosphere, 1 part iridium trichloride hydrate and 2.2 parts deuterated 5-(2-benzothiophene)pyrido[3,4-b]pyrazine were dissolved in a suitable amount of ethylene glycol monomethyl ether:water mixed solvent with a volume ratio of 3:1. The mixture was stirred at 110°C for 24 hours. After cooling to room temperature, a large amount of water was added, resulting in the formation of a black precipitate. The precipitate was filtered, washed with n-hexane, diethyl ether, and methanol, and dried to obtain a black dichloro-bridged product. No further purification was required, and this product was used directly as a substrate for subsequent auxiliary ligand reactions.

[0271] ESI-HRMS (High-resolution electrospray ionization mass spectrometry) [m / z]: 733.15 [1 / 2M-Cl] - ] + .

[0272] Example 27: Synthesis of the dichlorobridged intermediate corresponding to CTT25

[0273]

[0274] Synthesis method:

[0275] Under a nitrogen atmosphere, 1 part iridium trichloride hydrate and 2.2 parts deuterated 5-(2-thienothienoyl)pyridino[3,4-b]pyrazine were dissolved in a suitable amount of ethylene glycol monomethyl ether:water mixed solvent with a volume ratio of 3:1. The mixture was stirred at 110°C for 24 hours. After cooling to room temperature, a large amount of water was added, resulting in the formation of a black precipitate. The precipitate was filtered, washed with n-hexane, diethyl ether, and methanol, and dried to obtain a black dichloro-bridged product. No further purification was required, and this product was used directly as a substrate for subsequent auxiliary ligand reactions.

[0276] ESI-HRMS (High-resolution electrospray ionization mass spectrometry) [m / z]: 741.04 [1 / 2M-Cl] - ] + .

[0277] Example 28: Synthesis of the dichlorobridged intermediate corresponding to CT26

[0278]

[0279] Synthesis method:

[0280] Under a nitrogen atmosphere, 1 part iridium trichloride hydrate and 2.2 parts deuterated 2-phenyl-5-(2-thienyl)pyridino[3,4-b]pyrazine were dissolved in a suitable amount of ethylene glycol monomethyl ether:water mixed solvent with a volume ratio of 3:1. The mixture was stirred at 110°C for 24 hours. After cooling to room temperature, a large amount of water was added, resulting in the formation of a black precipitate. The precipitate was filtered, washed with n-hexane, diethyl ether, and methanol, and dried to obtain a black dichloro-bridged product. No further purification was required, and this product was used directly as a substrate for subsequent auxiliary ligand reactions.

[0281] ESI-HRMS (High-resolution electrospray ionization mass spectrometry) [m / z]: 789.21 [1 / 2M-Cl] - ] + .

[0282] Example 29: Synthesis of CT1

[0283]

[0284] Synthesis method:

[0285] One part of dichlorobridged substrate, three parts of acetylacetone, and three parts of potassium tert-butoxide were dissolved in a dichloromethane:ethanol solvent with a volume ratio of 3:1. The mixture was stirred at 30°C for 24 hours. After the reaction was completed and cooled, the organic phase was extracted with dichloromethane, washed with saturated brine, dried over anhydrous magnesium sulfate, concentrated, and purified by neutral alumina column chromatography to obtain a black solid product. The combined yield of the two steps was 45%.

[0286] ESI-HRMS (High-resolution electrospray ionization mass spectrometry) [m / z]: 717.07 [M+H] + .

[0287] Elemental analysis (C 27 H 19 IrN6O2S2):

[0288] Anal.Calcd (theoretical values): C, 45.30; H, 2.68; N, 11.74; O, 4.47; S, 8.96;

[0289] Found (measured values): C, 45.31; H, 2.66; N, 11.75; O, 4.47; S, 8.95.

[0290] Example 30: Synthesis of CT2

[0291]

[0292] Synthesis method:

[0293] One part of dichlorobridged substrate, three parts of acetylacetone, and three parts of potassium tert-butoxide were dissolved in a dichloromethane:ethanol solvent with a volume ratio of 3:1. The mixture was stirred at 30°C for 24 hours. After the reaction was completed and cooled, the organic phase was extracted with dichloromethane, washed with saturated brine, dried over anhydrous magnesium sulfate, concentrated, and purified by neutral alumina column chromatography to obtain a black solid product. The combined yield of the two steps was 43%.

[0294] ESI-HRMS (High-resolution electrospray ionization mass spectrometry) [m / z]: 869.13 [M+H] + .

[0295] Elemental analysis (C 39 H 27 IrN6O2S2):

[0296] Anal.Calcd (theoretical values): C, 53.97; H, 3.14; N, 9.68; O, 3.69; S, 7.39;

[0297] Found (measured values): C, 53.95; H, 3.15; N, 9.67; O, 3.70; S, 7.40.

[0298] Example 31: Synthesis of CT27

[0299]

[0300] Synthesis method:

[0301] One part of dichlorobridged substrate, three parts of acetylacetone, and three parts of potassium tert-butoxide were dissolved in a dichloromethane:ethanol solvent with a volume ratio of 3:1. The mixture was stirred at 30°C for 24 hours. After the reaction was completed and cooled, the organic phase was extracted with dichloromethane, washed with saturated brine, dried over anhydrous magnesium sulfate, concentrated, and purified by neutral alumina column chromatography to obtain a black solid product. The combined yield of the two steps was 43%.

[0302] ESI-HRMS (High-resolution electrospray ionization mass spectrometry) [m / z]: 869.13 [M+H] + .

[0303] Elemental analysis (C 39 H 27 IrN6O2S2):

[0304] Anal.Calcd (theoretical values): C, 53.97; H, 3.14; N, 9.68; O, 3.69; S, 7.39;

[0305] Found (measured values): C, 53.95; H, 3.15; N, 9.67; O, 3.70; S, 7.40.

[0306] Example 32: Synthesis of CBT1

[0307]

[0308] Synthesis method:

[0309] One part of dichlorobridged substrate, three parts of acetylacetone, and three parts of potassium tert-butoxide were dissolved in a dichloromethane:ethanol solvent with a volume ratio of 3:1. The mixture was stirred at 30°C for 24 hours. After the reaction was completed and cooled, the organic phase was extracted with dichloromethane, washed with saturated brine, dried over anhydrous magnesium sulfate, concentrated, and purified by neutral alumina column chromatography to obtain a black solid product. The combined yield of the two steps was 48%.

[0310] ESI-HRMS (High-resolution electrospray ionization mass spectrometry) [m / z]: 817.10 [M+H] + .

[0311] Elemental analysis (C 35 H 23 IrN6O2S2):

[0312] Anal.Calcd (theoretical values): C, 51.52; H, 2.84; N, 10.30; O, 3.92; S, 7.86;

[0313] Found (measured values): C, 51.53; H, 2.85; N, 10.29; O, 3.91; S, 7.86.

[0314] Example 33: Synthesis of CTT1

[0315]

[0316] Synthesis method:

[0317] One part of dichlorobridged substrate, three parts of acetylacetone, and three parts of potassium tert-butoxide were dissolved in a dichloromethane:ethanol solvent with a volume ratio of 3:1. The mixture was stirred at 30°C for 24 hours. After the reaction was completed and cooled, the organic phase was extracted with dichloromethane, washed with saturated brine, dried over anhydrous magnesium sulfate, concentrated, and purified by neutral alumina column chromatography to obtain a black solid product. The combined yield of the two steps was 39%.

[0318] ESI-HRMS (High-resolution electrospray ionization mass spectrometry) [m / z]: 829.02 [M+H] + .

[0319] Elemental analysis (C 31 H 19 IrN6O2S4):

[0320] Anal.Calcd (theoretical values): C, 44.97; H, 2.31; N, 10.15; O, 3.86; S, 15.49;

[0321] Found (measured values): C, 44.99; H, 2.30; N, 10.16; O, 3.84; S, 15.50.

[0322] Example 34: Synthesis of CCZ1

[0323]

[0324] Synthesis method:

[0325] One part of dichlorobridged substrate, three parts of acetylacetone, and three parts of potassium tert-butoxide were dissolved in a dichloromethane:ethanol solvent with a volume ratio of 3:1. The mixture was stirred at 30°C for 24 hours. After the reaction was completed and cooled, the organic phase was extracted with dichloromethane, washed with saturated brine, dried over anhydrous magnesium sulfate, concentrated, and purified by neutral alumina column chromatography to obtain a black solid product. The combined yield of the two steps was 37%.

[0326] ESI-HRMS (High-resolution electrospray ionization mass spectrometry) [m / z]: 1035.27 [M+H] + .

[0327] Elemental analysis (C 55 H 37 IrN8O2):

[0328] Anal.Calcd (theoretical values): C, 63.88; H, 3.61; N, 10.84; O, 3.09;

[0329] Found (measured values): C, 63.87; H, 3.60; N, 10.86; O, 3.09.

[0330] Example 35: Synthesis of CBF1

[0331]

[0332] Synthesis method:

[0333] One part of dichlorobridged substrate, three parts of acetylacetone, and three parts of potassium tert-butoxide were dissolved in a dichloromethane:ethanol solvent with a volume ratio of 3:1. The mixture was stirred at 30°C for 24 hours. After the reaction was completed and cooled, the organic phase was extracted with dichloromethane, washed with saturated brine, dried over anhydrous magnesium sulfate, concentrated, and purified by neutral alumina column chromatography to obtain a black solid product. The combined yield of the two steps was 37%.

[0334] ESI-HRMS (High-resolution electrospray ionization mass spectrometry) [m / z]: 885.18 [M+H] + .

[0335] Elemental analysis (C 43 H 27 IrN6O4):

[0336] Anal.Calcd (theoretical values): C, 58.43; H, 3.08; N, 9.51; O, 7.24;

[0337] Found (measured values): C, 58.44; H, 3.07; N, 9.52; O, 7.23.

[0338] Example 36: Synthesis of CT13

[0339]

[0340] Synthesis method:

[0341] Under a nitrogen atmosphere, 4-(phenylimino)-2-pentanone was dissolved in a suitable amount of diethyl ether. The colorless solution was frozen in cold hydrazine. The freezing apparatus was removed, and one equivalent of solid potassium benzyl was added during melting to obtain a colorless suspension, which was stirred at room temperature for 1 hour. Volatiles were removed under vacuum, and the colorless solid was suspended in a suitable amount of pentane and cooled to -35°C. The cold mixture was filtered, the product was washed with pentane, and dried under vacuum to obtain the auxiliary ligand potassium salt.

[0342] Under a nitrogen atmosphere, one part of the dichloro-bridged substrate was suspended in an appropriate amount of tetrahydrofuran, and a tetrahydrofuran solution containing two parts of the aforementioned potassium salt was added. After stirring at room temperature for 2.5 hours, the solvent was removed by vacuum concentration, and the product was purified by neutral alumina column chromatography to obtain a black solid product with an overall yield of 35%.

[0343] ESI-HRMS (High-resolution electrospray ionization mass spectrometry) [m / z]: 792.12 [M+H] + .

[0344] Elemental analysis (C 33 H 24 IrN7OS2):

[0345] Anal.Calcd (theoretical values): C, 50.11; H, 3.06; N, 12.40; O, 2.02; S, 8.11;

[0346] Found (measured values): C, 50.10; H, 3.05; N, 12.41; O, 2.02; S, 8.13.

[0347] Example 37: Synthesis of CT17

[0348]

[0349] Synthesis method:

[0350] Under a nitrogen atmosphere, 0.31 mmol of bromobenzene was dissolved in 2 mL of tetrahydrofuran. Under liquid nitrogen cooling, 0.1 mL of a 2.5 mol / L n-butyllithium solution in n-hexane was added to the reaction mixture, and the mixture was stirred for 30 minutes. The resulting reaction mixture was then added dropwise to 0.31 mmol of N,N'-diisopropylcarbodiimide, and the mixture was reacted for another 30 minutes under liquid nitrogen cooling. The resulting reaction mixture was then added dropwise to a Teflon-sealed glass tube containing 0.079 mmol of dichlorobridged complex and 5 mL of tetrahydrofuran. The mixture was stirred overnight at 80°C and then cooled to room temperature. After removing the volatile solvent by rotary evaporation, the crude solid product was dissolved in a minimal amount of tetrahydrofuran. n-Pentane was added dropwise to the solution, and a black solid precipitated. The product was then dissolved in a minimal amount of dichloromethane, and cyclohexane was added to precipitate the byproduct. The dichloromethane / n-hexane solution was evaporated by rotary evaporation to obtain the black solid product, with an overall yield of 31%.

[0351] ESI-HRMS (High-resolution electrospray ionization mass spectrometry) [m / z]: 821.18 [M+H] + .

[0352] Elemental analysis (C 35 H 31 IrN8S2):

[0353] Anal.Calcd (theoretical values): C, 51.26; H, 3.81; N, 13.66; S, 7.82;

[0354] Found (measured values): C, 51.25; H, 3.82; N, 13.67; S, 7.81.

[0355] Example 38: Synthesis of CT21

[0356]

[0357] Synthesis method:

[0358] One part of dichlorobridged substrate and 3.8 parts of 8-hydroxyquinoline were dissolved in an appropriate amount of dichloromethane:ethanol:triethylamine solvent in a volume ratio of 2:2:1. The mixture was stirred at 80°C for 16 hours. After the reaction was completed and cooled, the solvent was removed by rotary evaporation. The product was purified by neutral alumina column chromatography to obtain a black solid product with an overall yield of 37%.

[0359] ESI-HRMS (High-resolution electrospray ionization mass spectrometry) [m / z]: 762.07 [M+H] +.

[0360] Elemental analysis (C 31 H 18 IrN7OS2):

[0361] Anal.Calcd (theoretical values): C, 48.94; H, 2.38; N, 12.89; O, 2.10; S, 8.43;

[0362] Found (measured values): C, 48.92; H, 2.39; N, 12.90; O, 2.11; S, 8.41.

[0363] Example 39: Synthesis of CBT23

[0364]

[0365] Synthesis method:

[0366] One part of dichlorobridged substrate and 3.8 parts of 8-hydroxyquinoline were dissolved in an appropriate amount of dichloromethane:ethanol:triethylamine solvent in a volume ratio of 2:2:1. The mixture was stirred at 80°C for 16 hours. After the reaction was completed and cooled, the solvent was removed by rotary evaporation. The product was purified by neutral alumina column chromatography to obtain a black solid product with an overall yield of 35%.

[0367] ESI-HRMS (High-resolution electrospray ionization mass spectrometry) [m / z]: 1150.14 [M+H] + .

[0368] Elemental analysis (C 53 H 28 F6IrN7OS2):

[0369] Anal.Calcd (theoretical values): C, 55.39; H, 2.46; N, 8.53; O, 1.39; S, 5.58;

[0370] Found (measured values): C, 55.38; H, 2.47; N, 8.53; O, 1.38; S, 5.59.

[0371] Example 40: Synthesis of CTT20

[0372]

[0373] Synthesis method:

[0374] Under a nitrogen atmosphere, 0.31 mmol of bromobenzene was dissolved in 2 mL of tetrahydrofuran. Under liquid nitrogen cooling, 0.1 mL of a 2.5 mol / L n-butyllithium solution in n-hexane was added to the reaction mixture, and the mixture was stirred for 30 minutes. The resulting reaction mixture was then added dropwise to 0.31 mmol of N,N'-diisopropylcarbodiimide, and the mixture was reacted for another 30 minutes under liquid nitrogen cooling. The resulting reaction mixture was then added dropwise to a Teflon-sealed glass tube containing 0.079 mmol of dichlorobridged complex and 5 mL of tetrahydrofuran. The mixture was stirred overnight at 80°C and then cooled to room temperature. After removing the volatile solvent by rotary evaporation, the crude solid product was dissolved in a minimal amount of tetrahydrofuran. n-Pentane was added dropwise to the solution, and a black solid precipitated. The product was then dissolved in a minimal amount of dichloromethane, and cyclohexane was added to precipitate the byproduct. The dichloromethane / n-hexane solution was evaporated by rotary evaporation to obtain the black solid product, with an overall yield of 29%.

[0375] ESI-HRMS (High-resolution electrospray ionization mass spectrometry) [m / z]: 1349.38 [M+H] + .

[0376] Elemental analysis (C 71 H 63 IrN8S4):

[0377] Anal.Calcd (theoretical values): C, 63.23; H, 4.71; N, 8.31; S, 9.51;

[0378] Found (measured values): C, 63.24; H, 4.72; N, 8.30; S, 9.50.

[0379] Example 41: Synthesis of CBT25

[0380]

[0381] Synthesis method:

[0382] One part of dichlorobridged substrate, three parts of acetylacetone, and three parts of potassium tert-butoxide were dissolved in a dichloromethane:ethanol solvent with a volume ratio of 3:1. The mixture was stirred at 30°C for 24 hours. After the reaction was completed and cooled, the organic phase was extracted with dichloromethane, washed with saturated brine, dried over anhydrous magnesium sulfate, concentrated, and purified by neutral alumina column chromatography to obtain a black solid product. The combined yield of the two steps was 47%.

[0383] ESI-HRMS (High-resolution electrospray ionization mass spectrometry) [m / z]: 833.20 [M+H] + .

[0384] Elemental analysis (C 35 H7H 16IrN6O2S2):

[0385] Anal.Calcd (theoretical values): C, 50.52; H / D, 4.72; N, 10.10; O, 3.85; S, 7.71;

[0386] Found (measured values): C, 50.53; H / D, 4.70; N, 10.11; O, 3.85; S, 7.72.

[0387] Example 42: Synthesis of CTT25

[0388]

[0389] Synthesis method:

[0390] One part of dichlorobridged substrate, three parts of acetylacetone, and three parts of potassium tert-butoxide were dissolved in a dichloromethane:ethanol solvent with a volume ratio of 3:1. The mixture was stirred at 30°C for 24 hours. After the reaction was completed and cooled, the organic phase was extracted with dichloromethane, washed with saturated brine, dried over anhydrous magnesium sulfate, concentrated, and purified by neutral alumina column chromatography to obtain a black solid product. The combined yield of the two steps was 41%.

[0391] ESI-HRMS (High-resolution electrospray ionization mass spectrometry) [m / z]: 841.09 [M+H] + .

[0392] Elemental analysis (C 31 H7D 12 IrN6O2S4):

[0393] Anal.Calcd (theoretical values): C, 44.32; H / D, 3.72; N, 10.00; O, 3.81; S, 15.27;

[0394] Found (measured values): C, 44.34; H / D, 3.70; N, 10.01; O, 3.81; S, 15.26.

[0395] Example 43: Synthesis of CT26

[0396]

[0397] Synthesis method:

[0398] One part of dichlorobridged substrate, three parts of acetylacetone, and three parts of potassium tert-butoxide were dissolved in a dichloromethane:ethanol solvent with a volume ratio of 3:1. The mixture was stirred at 30°C for 24 hours. After the reaction was completed and cooled, the organic phase was extracted with dichloromethane, washed with saturated brine, dried over anhydrous magnesium sulfate, concentrated, and purified by neutral alumina column chromatography to obtain a black solid product. The combined yield of the two steps was 39%.

[0399] ESI-HRMS (High-resolution electrospray ionization mass spectrometry) [m / z]: 889.26 [M+H] + .

[0400] Elemental analysis (C 39 H7D 20 IrN6O2S2):

[0401] Anal.Calcd (theoretical values): C, 52.74; H / D, 5.33; N, 9.46; O, 3.60; S, 7.22;

[0402] Found (measured values): C, 52.75; H / D, 5.31; N, 9.47; O, 3.61; S, 7.21.

[0403] Example 44: Synthesis of CBT28

[0404]

[0405] Synthesis method:

[0406] One part of dichlorobridged substrate, three parts of acetylacetone, and three parts of potassium tert-butoxide were dissolved in a dichloromethane:ethanol solvent with a volume ratio of 3:1. The mixture was stirred at 30°C for 24 hours. After the reaction was completed and cooled, the organic phase was extracted with dichloromethane, washed with saturated brine, dried over anhydrous magnesium sulfate, concentrated, and purified by neutral alumina column chromatography to obtain a black solid product. The combined yield of the two steps was 45%.

[0407] ESI-HRMS (High-resolution electrospray ionization mass spectrometry) [m / z]: 1105.14 [M+H] + .

[0408] Elemental analysis (C 49 H 29 F6IrN6O2S2):

[0409] Anal.Calcd (theoretical values): C, 53.30; H, 2.65; N, 7.61; O, 2.90; S, 5.81;

[0410] Found (measured values): C, 53.32; H, 2.63; N, 7.61; O, 2.91; S, 5.80.

[0411] Example 45: Synthesis of CCZ5

[0412]

[0413] Synthesis method:

[0414] One part of dichlorobridged substrate, three parts of 2,2,6,6-tetramethyl-3,5-heptadecane, and three parts of potassium tert-butoxide were dissolved in a dichloromethane:ethanol solvent with a volume ratio of 3:1. The mixture was stirred at 30°C for 24 hours. After the reaction was completed and cooled, the organic phase was extracted with dichloromethane, washed with saturated brine, dried over anhydrous magnesium sulfate, concentrated, and purified by neutral alumina column chromatography to obtain a black solid product. The combined yield of the two steps was 36%.

[0415] ESI-HRMS (High-resolution electrospray ionization mass spectrometry) [m / z]: 1119.37 [M+H] + .

[0416] Elemental analysis (C 61 H 49 IrN8O2):

[0417] Anal.Calcd (theoretical values): C, 65.51; H, 4.42; N, 10.02; O, 2.86;

[0418] Found (measured values): C, 65.50; H, 4.43; N, 10.01; O, 2.87.

[0419] Example 46: Synthesis of CBF9

[0420]

[0421] Synthesis method:

[0422] One part of dichlorobridged substrate, three parts of 3,7-diethyl-4,6-nonanedione, and three parts of potassium tert-butoxide were dissolved in a dichloromethane:ethanol solvent with a volume ratio of 3:1. The mixture was stirred at 30°C for 24 hours. After the reaction was completed and cooled, the organic phase was extracted with dichloromethane, washed with saturated brine, dried over anhydrous magnesium sulfate, concentrated, and purified by neutral alumina column chromatography to obtain a black solid product. The combined yield of the two steps was 39%.

[0423] ESI-HRMS (High-resolution electrospray ionization mass spectrometry) [m / z]: 997.31 [M+H] + .

[0424] Elemental analysis (C 51 H 43 IrN6O4):

[0425] Anal.Calcd (theoretical values): C, 61.49; H, 4.35; N, 8.44; O, 6.42;

[0426] Found (measured values): C, 61.48; H, 4.34; N, 8.45; O, 6.43.

[0427] Example 47: Synthesis of 5-(4-tert-butyl-2-naphthyl)pyrido[3,4-b]pyrazine

[0428]

[0429] Under a nitrogen atmosphere, 1 part of 5-chloropyridino[3,4-b]pyrazine, 1.2 parts of 4-tert-butyl-2-naphthylboronic acid, 0.05 parts of tetrakis(triphenylphosphine)palladium, and 3 parts of potassium carbonate were dissolved in a suitable amount of 1,4-dioxane:water mixed solvent with a volume ratio of 3:1. The mixture was heated and stirred at 90°C for 24 hours. After the reaction was completed, the mixture was cooled to room temperature, filtered with diatomaceous earth, and washed with ethyl acetate. The organic phase was then separated by liquid chromatography, washed three times with saturated brine, dried over anhydrous magnesium sulfate, and purified by rotary evaporation of silica gel to remove the solvent. The product was then purified by silica gel column chromatography with petroleum ether:ethyl acetate as the eluent, and 2% triethylamine was added to reduce the adsorption of the target product on the silica gel column. The solvent was removed by rotary evaporation after collection, yielding a pale yellow solid product with a yield of 81%.

[0430] ESI-HRMS (High-resolution electrospray ionization mass spectrometry) [m / z]: 314.17 [M+H] + .

[0431] Elemental analysis (C 21 H 19 N3):

[0432] Anal.Calcd (theoretical values): C, 80.48; H, 6.11; N, 13.41;

[0433] Found (measured values): C, 80.48; H, 6.10; N, 13.42.

[0434] Example 48: Synthesis of dichlorobridged intermediates corresponding to CNP1,5,9,13,17,21

[0435]

[0436] Synthesis method:

[0437] Under a nitrogen atmosphere, 1 part iridium trichloride hydrate and 2.2 parts 5-(4-tert-butyl-2-naphthyl)pyridino[3,4-b]pyrazine were dissolved in a suitable amount of ethylene glycol monomethyl ether:water mixed solvent with a volume ratio of 3:1. The mixture was stirred at 110°C for 24 hours. After cooling to room temperature, a large amount of water was added, resulting in the formation of a black precipitate. The precipitate was filtered, washed with n-hexane, diethyl ether, and methanol, and dried to obtain a black dichloro-bridged product. No further purification was required, and this product was used directly as a substrate for subsequent auxiliary ligand reactions.

[0438] ESI-HRMS (High-resolution electrospray ionization mass spectrometry) [m / z]: 817.26 [1 / 2M-Cl] - ] + .

[0439] Example 49: Synthesis of CNP1

[0440]

[0441] Synthesis method:

[0442] One part of dichlorobridged substrate, three parts of acetylacetone, and three parts of potassium tert-butoxide were dissolved in a dichloromethane:ethanol solvent with a volume ratio of 3:1. The mixture was stirred at 30°C for 24 hours. After the reaction was completed and cooled, the organic phase was extracted with dichloromethane, washed with saturated brine, dried over anhydrous magnesium sulfate, concentrated, and purified by neutral alumina column chromatography to obtain a black solid product. The combined yield of the two steps was 42%.

[0443] ESI-HRMS (High-resolution electrospray ionization mass spectrometry) [m / z]: 917.32 [M+H] + .

[0444] Elemental analysis (C 47 H 43 IrN6O2):

[0445] Anal.Calcd (theoretical values): C, 61.62; H, 4.73; N, 9.17; O, 3.49;

[0446] Found (measured values): C, 61.63; H, 4.74; N, 9.16; O, 3.48.

[0447] Example 50: Synthesis of 2-(4-trifluoromethylphenyl)-5-(4-tert-butyl-2-naphthyl)pyrido[3,4-b]pyrazine and 3-(4-trifluoromethylphenyl)-5-(4-tert-butyl-2-naphthyl)pyrido[3,4-b]pyrazine

[0448]

[0449] Under a nitrogen atmosphere, 1 part of a mixture of 2-(4-trifluoromethylphenyl)-5-chloropyrido[3,4-b]pyrazine and 3-(4-trifluoromethylphenyl)-5-chloropyrido[3,4-b]pyrazine, 1.2 parts of 4-tert-butyl-2-naphthoboric acid, 0.05 parts of tetraphenylphosphine palladium, and 3 parts of potassium carbonate were dissolved in an appropriate amount of 1,4-dioxane:water mixed solvent with a volume ratio of 3:1. The mixture was heated and stirred at 90°C for 24 hours. After the reaction was completed, the mixture was cooled to room temperature, filtered with diatomaceous earth, and washed with ethyl acetate. The organic phase was then separated by liquid chromatography, washed three times with saturated brine, dried over anhydrous magnesium sulfate, and purified by rotary evaporation using silica gel adsorption. The eluent was petroleum ether:ethyl acetate, with 2% triethylamine added to reduce the adsorption of the target product on the silica gel column. 2-(4-trifluoromethylphenyl)-5-(4-tert-butyl-2-naphthyl)pyrido[3,4-b]pyrazine, being less polar, was eluted first, while 3-(4-trifluoromethylphenyl)-5-(4-tert-butyl-2-naphthyl)pyrido[3,4-b]pyrazine, being more polar, was eluted subsequently. Both were collected and the solvent was removed by rotary evaporation to give yellow solid products, with the former yielding 39% and the latter yielding 18%.

[0450] ESI-HRMS (High-resolution electrospray ionization mass spectrometry) [m / z]: 458.18 [M+H] + .

[0451] Elemental analysis (C 28 H 22 F3N3):

[0452] Anal.Calcd (theoretical values): C, 73.51; H, 4.85; N, 9.18;

[0453] Found (measured values): C, 73.52; H, 4.86; N, 9.19.

[0454] Example 51: Synthesis of dichlorobridged intermediates corresponding to CNP3,7,11,15,19,23

[0455]

[0456] Synthesis method:

[0457] Under a nitrogen atmosphere, 1 part iridium trichloride hydrate and 2.2 parts 2-(4-trifluoromethylphenyl)-5-(4-tert-butyl-2-naphthyl)pyridino[3,4-b]pyrazine were dissolved in a suitable amount of ethylene glycol monomethyl ether:water mixed solvent with a volume ratio of 3:1. The mixture was stirred at 110°C for 24 hours. After cooling to room temperature, a large amount of water was added, resulting in the formation of a black precipitate. The precipitate was filtered, washed with n-hexane, diethyl ether, and methanol, and dried to obtain a black dichloro-bridged product. No further purification was required, and this product was used directly as a substrate for subsequent auxiliary ligand reactions.

[0458] ESI-HRMS (High-resolution electrospray ionization mass spectrometry) [m / z]: 1105.30 [1 / 2M-Cl] - ] + .

[0459] Example 52: Synthesis of CNP3

[0460]

[0461] Synthesis method:

[0462] One part of dichlorobridged substrate, three parts of acetylacetone, and three parts of potassium tert-butoxide were dissolved in a dichloromethane:ethanol solvent with a volume ratio of 3:1. The mixture was stirred at 30°C for 24 hours. After the reaction was completed and cooled, the organic phase was extracted with dichloromethane, washed with saturated brine, dried over anhydrous magnesium sulfate, concentrated, and purified by neutral alumina column chromatography to obtain a black solid product. The combined yield of the two steps was 42%.

[0463] ESI-HRMS (High-resolution electrospray ionization mass spectrometry) [m / z]: 1205.35 [M+H] + .

[0464] Elemental analysis (C 61 H 49 F6IrN6O2):

[0465] Anal.Calcd (theoretical values): C, 60.84; H, 4.10; N, 6.98; O, 2.66;

[0466] Found (measured values): C, 60.85; H, 4.11; N, 6.97; O, 2.67.

[0467] Example 53: Synthesis of 5-(5-n-hexyl-2-thienyl)pyrido[3,4-b]pyrazine

[0468]

[0469] Under a nitrogen atmosphere, 1 part of 5-chloropyrido[3,4-b]pyrazine, 1.2 parts of 5-n-hexyl-2-thiophene tributyltin reagent, 0.05 parts of tetrakis(triphenylphosphine)palladium, and 3 parts of potassium fluoride were dissolved in an appropriate amount of 1,4-dioxane, and the mixture was stirred and heated at 110°C for 48 hours. After the reaction was completed, the mixture was cooled to room temperature, filtered through diatomaceous earth, and washed with ethyl acetate. The solvent was removed by rotary evaporation using silica gel adsorption, and the product was purified by silica gel column chromatography with petroleum ether:ethyl acetate as the eluent. 2% triethylamine was added to reduce the adsorption of the target product on the silica gel column. The solvent was collected and removed by rotary evaporation to give a yellow solid product with a yield of 70%.

[0470] ESI-HRMS (High-resolution electrospray ionization mass spectrometry) [m / z]: 298.14 [M+H] + .

[0471] Elemental analysis (C 17 H 19 N3S):

[0472] Anal.Calcd (theoretical values): C, 68.65; H, 6.44; N, 14.13; S, 10.78;

[0473] Found (measured values): C, 68.64; H, 6.43; N, 14.15; S, 10.79.

[0474] Example 54: Synthesis of 5-(5-trifluoromethyl-2-benzothienyl)pyrido[3,4-b]pyrazine

[0475]

[0476] Under a nitrogen atmosphere, 1 part of 5-chloropyrido[3,4-b]pyrazine, 1.2 parts of 5-trifluoromethyl-2-benzothiophene boric acid, 0.05 parts of tetraphenylphosphine palladium, and 3 parts of potassium carbonate were dissolved in an appropriate amount of 1,4-dioxane:water mixed solvent with a volume ratio of 3:1. The mixture was heated and stirred at 90°C for 24 hours. After the reaction was completed, the mixture was cooled to room temperature, filtered with diatomaceous earth, and washed with ethyl acetate. The organic phase was then separated by liquid chromatography, washed three times with saturated brine, dried over anhydrous magnesium sulfate, and purified by rotary evaporation using silica gel adsorption. The eluent was petroleum ether:ethyl acetate, with 2% triethylamine added to reduce the adsorption of the target product on the silica gel column. The solvent was removed by rotary evaporation, yielding a yellow solid product with a yield of 72%.

[0477] ESI-HRMS (High-resolution electrospray ionization mass spectrometry) [m / z]: 332.05 [M+H] + .

[0478] Elemental analysis (C 16 H8F3N3S):

[0479] Anal.Calcd (theoretical values): C, 58.00; H, 2.43; N, 12.68; S, 9.68;

[0480] Found (measured values): C, 58.01; H, 2.42; N, 12.67; S, 9.69.

[0481] Example 55: Synthesis of 2-phenyl-5-(5-trifluoromethyl-2-thienyl)pyrido[3,4-b]pyrazine and 3-phenyl-5-(5-trifluoromethyl-2-thienyl)pyrido[3,4-b]pyrazine

[0482]

[0483] Under a nitrogen atmosphere, 1 part of a mixture of 2-phenyl-5-chloropyrido[3,4-b]pyrazine and 3-phenyl-5-chloropyrido[3,4-b]pyrazine, 1.2 parts of 5-trifluoromethyl-2-thiophene tributyltin reagent, 0.05 parts of tetrakis(triphenylphosphine)palladium, and 3 parts of potassium fluoride were dissolved in an appropriate amount of 1,4-dioxane. The mixture was stirred and heated at 110°C for 48 hours. After the reaction was completed, the mixture was cooled to room temperature, filtered with diatomaceous earth, and washed with ethyl acetate. The solvent was removed by rotary evaporation using silica gel adsorption, and the product was purified by silica gel column chromatography with petroleum ether:ethyl acetate as the eluent. 2% triethylamine was added to reduce the adsorption of the target product on the silica gel column. 2-Phenylacetyl-5-(5-trifluoromethyl-2-thienyl)pyrido[3,4-b]pyrazine, being less polar, was eluted first, while 3-Phenylacetyl-5-(5-trifluoromethyl-2-thienyl)pyrido[3,4-b]pyrazine, being more polar, was eluted subsequently. Both were collected and the solvent was removed by rotary evaporation to give yellow solid products, with the former yielding 44% and the latter yielding 20%.

[0484] ESI-HRMS (High-resolution electrospray ionization mass spectrometry) [m / z]: 358.06 [M+H] + .

[0485] Elemental analysis (C 18 H 10 F3N3S):

[0486] Anal.Calcd (theoretical values): C, 60.50; H, 2.82; N, 11.76; S, 8.97;

[0487] Found (measured values): C, 60.49; H, 2.83; N, 11.75; S, 8.98.

[0488] Example 56: Synthesis of dichlorobridged intermediates corresponding to CT33,37,41

[0489]

[0490] Synthesis method:

[0491] Under a nitrogen atmosphere, 1 part iridium trichloride hydrate and 2.2 parts 5-(5-n-hexyl-2-thienyl)pyrido[3,4-b]pyrazine were dissolved in a suitable amount of ethylene glycol monomethyl ether:water mixed solvent with a volume ratio of 3:1. The mixture was stirred at 110°C for 24 hours. After cooling to room temperature, a large amount of water was added, resulting in the formation of a black precipitate. The precipitate was filtered, washed with n-hexane, diethyl ether, and methanol, and dried to obtain a black dichloro-bridged product. No further purification was required, and this product was used directly as a substrate for subsequent auxiliary ligand reactions.

[0492] ESI-HRMS (High-resolution electrospray ionization mass spectrometry) [m / z]: 785.21 [1 / 2M-Cl] - ] + .

[0493] Example 57: Synthesis of dichlorobridged intermediates corresponding to CBT33,37,41

[0494]

[0495] Synthesis method:

[0496] Under a nitrogen atmosphere, 1 part iridium trichloride hydrate and 2.2 parts 5-(5-trifluoromethyl-2-benzothiophene)pyrido[3,4-b]pyrazine were dissolved in a suitable amount of ethylene glycol monomethyl ether:water mixed solvent with a volume ratio of 3:1. The mixture was stirred at 110°C for 24 hours. After cooling to room temperature, a large amount of water was added, resulting in the formation of a black precipitate. The precipitate was filtered, washed with n-hexane, diethyl ether, and methanol, and dried to obtain a black dichloro-bridged product. No further purification was required, and this product was directly used as a substrate for subsequent auxiliary ligand reactions.

[0497] ESI-HRMS (High-resolution electrospray ionization mass spectrometry) [m / z]: 853.03 [1 / 2M-Cl] - ] + .

[0498] Example 58: Synthesis of dichlorobridged intermediates corresponding to CT46,50,54

[0499]

[0500] Synthesis method:

[0501] Under a nitrogen atmosphere, 1 part iridium trichloride hydrate and 2.2 parts 2-phenyl-5-(5-trifluoromethyl-2-thienyl)pyridino[3,4-b]pyrazine were dissolved in a suitable amount of ethylene glycol monomethyl ether:water mixed solvent with a volume ratio of 3:1. The mixture was stirred at 110°C for 24 hours. After cooling to room temperature, a large amount of water was added, resulting in the formation of a black precipitate. The precipitate was filtered, washed with n-hexane, diethyl ether, and methanol, and dried to obtain a black dichloro-bridged product. No further purification was required, and this product was used directly as a substrate for subsequent auxiliary ligand reactions.

[0502] ESI-HRMS (High-resolution electrospray ionization mass spectrometry) [m / z]: 905.06 [1 / 2M-Cl] - ] + .

[0503] Example 59: Synthesis of CT33

[0504]

[0505] Synthesis method:

[0506] One part of dichlorobridged substrate, three parts of acetylacetone, and three parts of potassium tert-butoxide were dissolved in a dichloromethane:ethanol solvent with a volume ratio of 3:1. The mixture was stirred at 30°C for 24 hours. After the reaction was completed and cooled, the organic phase was extracted with dichloromethane, washed with saturated brine, dried over anhydrous magnesium sulfate, concentrated, and purified by neutral alumina column chromatography to obtain a black solid product. The combined yield of the two steps was 43%.

[0507] ESI-HRMS (High-resolution electrospray ionization mass spectrometry) [m / z]: 885.26 [M+H] + .

[0508] Elemental analysis (C 39 H 43 IrN6O2S2):

[0509] Anal.Calcd (theoretical values): C, 52.98; H, 4.90; N, 9.51; O, 3.62; S, 7.25;

[0510] Found (measured values): C, 52.97; H, 4.90; N, 9.50; O, 3.64; S, 7.24.

[0511] Example 60: Synthesis of CT46

[0512]

[0513] Synthesis method:

[0514] One part of dichlorobridged substrate, three parts of acetylacetone, and three parts of potassium tert-butoxide were dissolved in a dichloromethane:ethanol solvent with a volume ratio of 3:1. The mixture was stirred at 30°C for 24 hours. After the reaction was completed and cooled, the organic phase was extracted with dichloromethane, washed with saturated brine, dried over anhydrous magnesium sulfate, concentrated, and purified by neutral alumina column chromatography to obtain a black solid product. The combined yield of the two steps was 39%.

[0515] ESI-HRMS (High-resolution electrospray ionization mass spectrometry) [m / z]: 1005.11 [M+H] + .

[0516] Elemental analysis (C 41 H 25 F6IrN6O2S2):

[0517] Anal.Calcd (theoretical values): C, 49.05; H, 2.51; N, 8.37; O, 3.19; S, 6.39;

[0518] Found (measured values): C, 49.04; H, 2.52; N, 8.37; O, 3.18; S, 6.40.

[0519] Example 61: Synthesis of CBT33

[0520]

[0521] Synthesis method:

[0522] One part of dichlorobridged substrate, three parts of acetylacetone, and three parts of potassium tert-butoxide were dissolved in a dichloromethane:ethanol solvent with a volume ratio of 3:1. The mixture was stirred at 30°C for 24 hours. After the reaction was completed and cooled, the organic phase was extracted with dichloromethane, washed with saturated brine, dried over anhydrous magnesium sulfate, concentrated, and purified by neutral alumina column chromatography to obtain a black solid product. The combined yield of the two steps was 42%.

[0523] ESI-HRMS (High-resolution electrospray ionization mass spectrometry) [m / z]: 953.08 [M+H] + .

[0524] Elemental analysis (C 37 H 21 F6IrN6O2S2):

[0525] Anal.Calcd (theoretical values): C, 46.68; H, 2.22; N, 8.83; O, 3.36; S, 6.74;

[0526] Found (measured values): C, 46.67; H, 2.21; N, 8.85; O, 3.37; S, 6.73.

[0527] Applications and implementation methods of the iridium metal complex prepared by this invention:

[0528] The iridium metal complex of the present invention can be used as a light-emitting material in organic electroluminescent devices, i.e., OLED devices.

[0529] An OLED includes a first electrode and a second electrode, and an organic material layer located between the electrodes. This organic material layer can be further divided into multiple regions. For example, the organic material layer may include a hole transport region, a light-emitting layer, and an electron transport region.

[0530] In specific embodiments, a substrate can be used below the first electrode or above the second electrode. The substrate is typically made of glass or polymer material with excellent mechanical strength, thermal stability, water resistance, and transparency. Furthermore, thin-film transistors (TFTs) can also be incorporated into the substrate used for displays.

[0531] The first electrode can be formed by sputtering or depositing the material to be used as the first electrode on a substrate. When the first electrode is used as the anode, it can be a transparent conductive oxide material such as indium tin oxide (ITO), indium zinc oxide (IZO), tin dioxide (SnO2), zinc oxide (ZnO), or any combination thereof. When the first electrode is used as the cathode, it can be a metal or alloy such as magnesium (Mg), silver (Ag), aluminum (Al), aluminum-lithium (Al-Li), calcium (Ca), magnesium-indium (Mg-In), magnesium-silver (Mg-Ag), or any combination thereof.

[0532] Organic material layers can be formed on electrodes using methods such as vacuum thermal evaporation, spin coating, and printing. The compounds used as organic material layers can be small organic molecules, large organic molecules, polymers, and combinations thereof.

[0533] The hole transport region is located between the anode and the light-emitting layer. The hole transport region can be a single-layer hole transport layer (HTL), including a single-layer hole transport layer containing only one compound and a single-layer hole transport layer containing multiple compounds. The hole transport region can also be a multilayer structure including at least one of a hole injection layer (HIL), a hole transport layer (HTL), and an electron blocking layer (EBL).

[0534] The material for the hole transport region can be selected from, but is not limited to, phthalocyanine derivatives such as CuPc, conductive polymers or polymers containing conductive dopants such as polyphenylene oxide, polyaniline / dodecylbenzenesulfonic acid (Pani / DBSA), poly(3,4-ethylenedioxythiophene) / poly(4-styrenesulfonate) (PEDOT / PSS), polyaniline / camphorsulfonic acid (Pani / CSA), polyaniline / poly(4-styrenesulfonate) (Pani / PSS), and aromatic amine derivatives.

[0535] The hole injection layer is located between the anode and the hole transport layer. The hole injection layer can be a single compound or a combination of multiple compounds.

[0536] The OLED organic material layer may also include an electron transport region between the light-emitting layer and the cathode. The electron transport region can be a single-layer electron transport layer (ETL), including single-layer electron transport layers containing only one compound and single-layer electron transport layers containing multiple compounds. Alternatively, the electron transport region can be a multilayer structure including at least one of an electron injection layer (EIL), an electron transport layer (ETL), and a hole blocking layer (HBL).

[0537] The device may also include an electron injection layer located between the electron transport layer and the cathode. The electron injection layer material includes, but is not limited to, one or more combinations of the following: LiQ, LiF, NaCl, CsF, Li2O, Cs2CO3, BaO, Na, Li, Ca.

[0538] The technical effects and advantages of the present invention will be demonstrated and verified by specifically applying the compounds of the present invention to organic electroluminescent devices and testing their actual performance.

[0539] To facilitate comparison of the device application performance of the luminescent materials of the present invention, comparative device examples were prepared using the prior art compounds TCNIr, M1, M2 and M3 as comparative materials in the application examples of the present invention, as shown below. These were compared with organic electroluminescent devices prepared using the compounds CT1, CBT1, CTT1, CCZ1, CT2, CT27, CT21, CBT23, CTT20, CBF1, CBT25, CTT25, CT26, CT13, CT17, CBT28, CCZ5, CBF9, CNP1, CNP3, CT33, CT46 and CBT33 of the present invention.

[0540]

[0541]

[0542] The following device examples 1 to 23 and comparative device examples 1-4 all fabricated an organic electroluminescent device 10, and the specific structure of the device is as follows: Figure 1 As shown.

[0543] The organic light-emitting devices 10 are numbered OLED-1 (CT1), OLED-2 (CBT1), OLED-3 (CTT1), OLED-4 (CCZ1), OLED-5 (CT2), OLED-6 (CT27), OLED-7 (CT21), OLED-8 (CBT23), OLED-9 (CTT20), OLED-10 (CBF1), OLED-11 (CBT25), OLED-12 (CTT25), OLED-13 (CT26), OLED-14 (CT13), OLED-15 (CT17), OLED-16 (CBT28), OLED-17 (CCZ5), OLED-18 (CBF9), OLED-19 (CNP1), OLED-20 (CNP3), OLED-21 (CT33), OLED-22 (CT46), OLED-23 (CBT33), OLED-24 (TCNIr), OLED-25 (M1), OLED-26 (M2), and OLED-27 (M3).

[0544] Device Example 1: Fabrication of OLED-1 (CT1)

[0545] The device structure is: ITO / HATCN (20nm) / TAPC (40nm) / mCP (5nm) / CBP:15wt%CT1 (30nm) / TPBi (40nm) / LiF (1nm) / Al (100nm), which means: HATCN forms a film with a thickness of 20nm; TAPC forms a film with a thickness of 40nm; mCP forms a film with a thickness of 5nm; CBP and 15wt%CT1 form a film with a thickness of 30nm; TPBi forms a film with a thickness of 40nm; LiF forms a film with a thickness of 1nm; and Al forms a film with a thickness of 100nm.

[0546] The structural formulas of the various organic materials used in each embodiment are as follows:

[0547]

[0548] The specific fabrication process of this device embodiment is as follows:

[0549] A glass plate coated with an ITO transparent conductive layer is ultrasonically treated in a commercial cleaning agent, rinsed in deionized water, ultrasonically degreased in an acetone:ethanol mixed solvent, baked in a clean environment until all moisture is removed, cleaned with ultraviolet light and ozone, and bombarded with a low-energy cation beam to obtain a glass plate with an anode 120, wherein the ITO transparent conductive layer is the anode 120.

[0550] The glass plate with the anode 120 was placed in a vacuum chamber and evacuated to a vacuum level of 1×10⁻⁶. -5 ~9×10 -3 Pa, HATCN, TAPC, and mCP are sequentially vacuum-deposited on the anode 120 as hole transport layer 130, with a deposition rate of 0.1 nm / s and a deposition film thickness of 20 / 40 / 5 nm.

[0551] A CBP thin film doped with the compound CT1 of the present invention is vacuum-deposited on the surface of the hole transport layer 130 away from the glass plate as the organic light-emitting layer 140 of the device. The evaporation rate ratio of CT1 to CBP is 15:85, the doping concentration of CT1 in CBP is 15wt%, the total evaporation rate is 0.1nm / s, and the total film thickness is 30nm.

[0552] A layer of TPBi material is vacuum-deposited on the organic light-emitting layer 140 as the electron transport layer 150 of the organic electroluminescent device 10. The deposition rate is 0.1 nm / s and the total film thickness is 40 nm.

[0553] On the surface of the electron transport layer 150 away from the organic light-emitting layer 140, LiF and Al layers are sequentially vacuum-deposited as the cathode 160 of the organic electroluminescent device 10. The deposition rate of LiF is 0.1 nm / s and the thickness is 1 nm, while the deposition rate of the Al layer is 0.3 nm / s and the thickness is 100 nm.

[0554] Device Example 2: Fabrication of OLED-2 (CBT1)

[0555] This embodiment is basically the same as device embodiment 1, except that the iridium metal complex is CBT1.

[0556] Device Example 3: Fabrication of OLED-3 (CTT1)

[0557] This embodiment is basically the same as device embodiment 1, except that the iridium metal complex is CTT1.

[0558] Device Example 4: Fabrication of OLED-4 (CCZ1)

[0559] This embodiment is basically the same as device embodiment 1, except that the iridium metal complex is CCZ1.

[0560] Device Example 5: Fabrication of OLED-5 (CT2)

[0561] This embodiment is basically the same as the device embodiment 1, except that the iridium metal complex is CT2.

[0562] Device Example 6: Fabrication of OLED-6 (CT27)

[0563] This embodiment is basically the same as the device embodiment 1, except that the iridium metal complex is CT27.

[0564] Device Example 7: Fabrication of OLED-7 (CT21)

[0565] This embodiment is basically the same as the device embodiment 1, except that the iridium metal complex is CT21.

[0566] Device Example 8: Fabrication of OLED-8 (CBT23)

[0567] This embodiment is basically the same as device embodiment 1, except that the iridium metal complex is CBT23.

[0568] Device Example 9: Fabrication of OLED-9 (CTT20)

[0569] This embodiment is basically the same as device embodiment 1, except that the iridium metal complex is CTT20.

[0570] Device Example 10: Fabrication of OLED-10 (CBF1)

[0571] This embodiment is basically the same as device embodiment 1, except that the iridium metal complex is CBF1.

[0572] Device Example 11: Fabrication of OLED-11 (CBT25)

[0573] This embodiment is basically the same as the device embodiment 1, except that the iridium metal complex is CBT25.

[0574] Device Example 12: Fabrication of OLED-12 (CTT25)

[0575] This embodiment is basically the same as the device embodiment 1, except that the iridium metal complex is CTT25.

[0576] Device Example 13: Fabrication of OLED-13 (CT26)

[0577] This embodiment is basically the same as the device embodiment 1, except that the iridium metal complex is CT26.

[0578] Device Example 14: Fabrication of OLED-14 (CT13)

[0579] This embodiment is basically the same as the device embodiment 1, except that the iridium metal complex is CT13.

[0580] Device Example 15: Fabrication of OLED-15 (CT17)

[0581] This embodiment is basically the same as the device embodiment 1, except that the iridium metal complex is CT17.

[0582] Device Example 16: Fabrication of OLED-16 (CBT28)

[0583] This embodiment is basically the same as device embodiment 1, except that the iridium metal complex is CBT28.

[0584] Device Example 17: Fabrication of OLED-17 (CCZ5)

[0585] This embodiment is basically the same as the device embodiment 1, except that the iridium metal complex is CCZ5.

[0586] Device Example 18: Fabrication of OLED-18 (CBF9)

[0587] This embodiment is basically the same as device embodiment 1, except that the iridium metal complex is CBF9.

[0588] Device Example 19: Fabrication of OLED-19 (CNP1)

[0589] This embodiment is basically the same as device embodiment 1, except that the iridium metal complex is CNP1.

[0590] Device Example 20: Fabrication of OLED-20 (CNP3)

[0591] This embodiment is basically the same as device embodiment 1, except that the iridium metal complex is CNP3.

[0592] Device Example 21: Fabrication of OLED-21 (CT33)

[0593] This embodiment is basically the same as device embodiment 1, except that the iridium metal complex is CT33.

[0594] Device Example 22: Fabrication of OLED-22 (CT46)

[0595] This embodiment is basically the same as device embodiment 1, except that the iridium metal complex is CT46.

[0596] Device Example 23: Fabrication of OLED-23 (CBT33)

[0597] This embodiment is basically the same as device embodiment 1, except that the iridium metal complex is CBT33.

[0598] Comparative Device Example 1: Fabrication of OLED-24 (TCNIr)

[0599] This embodiment is basically the same as device embodiment 1, except that the iridium metal complex is TCNIr.

[0600] Comparative Device Example 2: Fabrication of OLED-25 (M1)

[0601] This embodiment is basically the same as device embodiment 1, except that the iridium metal complex is M1.

[0602] Comparative Device Example 3: Fabrication of OLED-26 (M2)

[0603] This embodiment is basically the same as the device embodiment 1, except that the iridium metal complex is M2.

[0604] Comparative Device Example 4: Fabrication of OLED-27 (M3)

[0605] This embodiment is basically the same as the device embodiment 1, except that the iridium metal complex is M3.

[0606] The device performance of OLED-1 to OLED-27 prepared above is detailed in Table 1 below.

[0607] Table 1:

[0608]

[0609]

[0610] Figures 2 to 5 This is a characterization diagram of the OLED-5, from which the emission wavelength, current density, irradiance, and maximum external quantum efficiency of the OLED-5 can be determined. Figure 5 It can be seen that the maximum external quantum efficiency of the OLED-5 can reach 11.4%. Under high current density conditions, the OLED-5 still maintains a high external quantum efficiency, and the efficiency rolls off very slowly with the increase of current density.

[0611] Therefore, from Table 1 and Figures 2 to 4 It has been found that the organic electroluminescent device prepared by this invention can emit light in the near-infrared region. Compared with the compound TCNIr reported in the prior art, which uses cyano-substituted isoquinoline as the coordinating nitrogen terminator, the diazapyrogenation significantly red-shifts the emission wavelength. Meanwhile, the organic electroluminescent device using the compound CT2 of this invention has an irradiance of 100 W / m².2 (20V) and above, it has higher luminous efficiency and very low efficiency roll-off.

[0612] Compared to existing compounds M1, M2, and M3, which employ substituted or unsubstituted phenyl / pyridyl groups as coordinating carbon terminals, the complexes of this invention possess electron-rich carbon terminals that result in a significant redshift in emission wavelength, with peak values ​​all above 780 nm, achieving pure near-infrared emission. When the coordinating carbon terminal is an N-phenylcarbazole group, the emission peak wavelength can reach above 900 nm. Compared to existing compounds, devices fabricated using the iridium metal complexes of this application exhibit higher irradiance and external quantum efficiency while achieving pure near-infrared emission with a significant redshift in wavelength.

[0613] The performance comparison results of the devices prepared according to the present invention above show that the organic electroluminescent devices prepared using the compounds of the present invention have the advantage of significantly improved luminous efficiency compared with devices prepared using the prior art compound TCNIr. The specific reasons are as follows: First, because the main ligand of the compounds of the present invention adopts a double N-heteromorphic modification method rather than an exocyclic cyano substitution, compared with the main ligand of the prior art compound TCNIr, it more directly and effectively reduces the overall LUMO energy level of the complex, resulting in a significant redshift of the emission wavelength of the complex under the premise of similar ligand conjugation scale.

[0614] Furthermore, the emission wavelength of the complex can be further redshifted by replacing the coordinating carbon terminal with a more electron-rich one, such as benzothiophene, bis(thiophene), N-phenylcarbazole, and dibenzofuran groups, resulting in the reddest emission wavelength of OLED-4 shifting to 916 nm. The efficiency of devices fabricated using iridium complexes can also be improved by increasing substitution along the Ir-N bond axis, with OLED-5 and OLED-6 showing a significant efficiency improvement over OLED-1. Replacing the aliphatic auxiliary ligand with an electron-rich aromatic auxiliary ligand can raise the occupied orbital energy level of the iridium metal center in the iridium complex, narrowing the emission bandgap and further redshifting the emission wavelength. Simultaneously, it can reduce the energy level difference between the occupied orbitals of the iridium metal center and the occupied orbitals of the ligands, promoting indirect spin-orbit coupling within the iridium complex, increasing the radiative transition rate, improving the luminescence efficiency of the iridium complex, and ultimately enhancing the luminescence performance of iridium complex devices. In comparison, OLED-7 shows a redshift in wavelength and improved performance compared to OLED-1. By combining the two methods, OLED-8 shows a significant performance improvement compared to OLED-2, and OLED-9 shows a significant performance improvement compared to OLED-3.

[0615] Furthermore, after deuteration of the main ligand of the complex, the emission wavelength remains unchanged, but the use of low-frequency CD bonds to replace high-frequency CH bonds reduces non-radiative losses caused by high-frequency CH bond vibrational coupling, thereby improving the luminescence efficiency of the complex and the device efficiency. In comparison, OLED-11 shows significant performance improvements over OLED-2, OLED-12 over OLED-3, and OLED-13 over OLED-5.

[0616] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0617] It should be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present invention will not describe the various possible combinations separately. Different embodiments of the present invention can also be arbitrarily combined, as long as they do not violate the spirit of the present invention, and should also be considered as part of the content disclosed in the present invention.

Claims

1. An iridium metal complex with the molecular formula L₂IrA, wherein Ir is the central metal atom, L is the main ligand, and A is the auxiliary ligand, having a structure shown in any one of the following formulas (2-1), (2-2), (2-3), (2-4), (2-5), or (2-6): In formulas (2-1), (2-2), (2-3), (2-4), (2-5), and (2-6), R represents a single substituted group up to the maximum permissible number of substituted groups, and R is selected from one of hydrogen, deuterium, halogen, substituted or unsubstituted C1-C30 alkyl or cycloalkyl, substituted or unsubstituted C1-C30 haloalkyl or halocycloalkyl, and substituted or unsubstituted C6-C30 aryl. The auxiliary ligand A is selected from one of N^COOH, N^OH, β-diketone or N^NH; R1 represents a single substituted group up to the maximum allowed number of substituted groups, and R1 is selected from hydrogen, deuterium, halogen, C1-C12 alkyl or haloalkyl, and C6-C30 aryl. When R is selected from a group having a substituent, the substituent is selected from one or a combination of two of the following: deuterium, halogen, C1-C12 alkyl or haloalkyl, and C6-C30 aryl.

2. The iridium metal complex according to claim 1, characterized in that, In formulas (2-1), (2-2), (2-3), (2-4), (2-5), or (2-6), at least one hydrogen atom is replaced by a deuterium atom.

3. The iridium metal complex according to claim 1, characterized in that, In equations (2-1), (2-2), (2-3), (2-4), (2-5), and (2-6): The R is selected from hydrogen, deuterium, fluorine, chlorine, C1-C6 alkyl, C1-C6 fluoroalkyl, C1-C6 chloroalkyl, or substituted or unsubstituted groups of the following: phenyl, biphenyl, naphthyl, anthracene; when R is selected from a substituent, the substituent is selected from one or a combination of two of deuterium, fluorine, chlorine, C1-C6 alkyl, C1-C3 fluoroalkyl, and C1-C3 chloroalkyl. R1 is selected from one or a combination of two of the following: hydrogen, deuterium, fluorine, chlorine, C1-C6 alkyl, C1-C6 fluoroalkyl, C1-C6 chloroalkyl, phenyl, biphenyl, naphthyl, and anthracene.

4. The iridium metal complex according to claim 1, characterized in that, In formulas (2-1), (2-2), (2-3), (2-4), (2-5), and (2-6), R is selected from hydrogen, deuterium, or substituted or unsubstituted phenyl groups. When R is selected from substituted phenyl groups, the substituents on the phenyl group are selected from deuterium, methyl, trifluoromethyl, tert-butyl, phenyl, tert-butylphenyl, or trifluoromethylphenyl. R1 is selected from hydrogen, deuterium, methyl, trifluoromethyl, tert-butyl, hexyl, phenyl, tert-butylphenyl or trifluoromethylphenyl.

5. The iridium metal complex according to claim 1, characterized in that, It is an iridium metal complex as follows:

6. The application of the iridium metal complex according to any one of claims 1-5, characterized in that, The application is as a luminescent material in organic electroluminescent devices.

7. An organic electroluminescent device, comprising a first electrode, a second electrode, and one or more light-emitting functional layers inserted between the first electrode and the second electrode, characterized in that, The light-emitting functional layer includes at least one iridium metal complex as described in any one of claims 1-5.

8. The organic electroluminescent device according to claim 7, wherein the light-emitting functional layer comprises a hole transport region, a light-emitting layer, and an electron transport region, wherein the hole transport region is formed on the first electrode layer, the second electrode layer is formed on the electron transport region, and the light-emitting layer is located between the hole transport region and the electron transport region; wherein, The light-emitting layer contains an iridium metal complex as described in any one of claims 1-5.

Images