Metal iridium complex and organic electroluminescent device

Abstract

The application discloses a metal iridium complex and an organic electroluminescent device, and relates to the technical field of organic electroluminescent materials. The structural general formula of the metal iridium complex is (La)2IrLb, and the structural formula is as shown in formula I: wherein at least one of R1 or R2 comprises a structure of formula II: the dotted line in formula II represents direct bonding with ring A or ring B; the organic electroluminescent device prepared from the metal iridium complex in the application can improve the intermolecular spatial configuration, increase the radiation transition, reduce the molecular stacking, and has good spatial torsion capacity, thereby avoiding the carrier migration; when the metal iridium complex is used as a specific doping material of a light-emitting layer and applied to the organic electroluminescent device, the metal iridium complex has the advantages of low evaporation temperature, high photoelectrochemical stability, high luminous efficiency, long device service life and the like, and is suitable for industrialized production.

Description

Technical Field

[0001] This invention relates to the field of organic electroluminescent materials technology, and more specifically, to a metal iridium complex and an organic electroluminescent device. Background Technology

[0002] Currently, organic light-emitting diodes (OLEDs), as a next-generation display technology, are receiving increasing attention in both display and lighting technologies, with a very broad application prospect. However, compared with market application requirements, the performance of OLED devices, such as luminous efficiency, driving voltage, and lifespan, still needs further improvement.

[0003] Generally, the basic structure of an OLED device consists of thin films of various functional organic materials sandwiched between metal electrodes. Driven by an electric current, holes and electrons are injected from the anode and cathode, respectively. After traveling a certain distance, the holes and electrons recombine in the light-emitting layer and are released as light or heat, thus producing OLED light emission. However, organic functional materials are the core component of organic electroluminescent devices, and their thermal stability, photochemical stability, electrochemical stability, quantum yield, film-forming stability, crystallinity, and color saturation are all major factors affecting device performance.

[0004] Generally, organic functional materials include fluorescent materials and phosphorescent materials. Fluorescent materials are usually small organic molecules that can only utilize 25% of their singlet state energy for emission, resulting in relatively low luminescence efficiency. Phosphorescent materials, due to the spin-orbit coupling effect caused by heavy atoms, can utilize not only the 25% singlet state energy but also the energy of the 75% triplet exciton energy, thus achieving higher luminescence efficiency.

[0005] Compared to fluorescent materials, phosphorescent materials are a relatively recent development, and the thermal stability, lifetime, and color saturation of currently disclosed organic phosphorescent materials all need improvement. CN107973823A discloses a class of quinoline-based iridium compounds; the color saturation and device performance of these compounds, especially luminous efficiency and lifetime, need further improvement. CN106459114A discloses a class of iridium compounds coordinated by β-diketone ligands; these compounds have high sublimation temperatures and poor color saturation, particularly in terms of device luminous efficiency and lifetime, requiring further improvement. CN111377969A discloses a class of dibenzofuran-isoquinoline iridium complexes; the device performance of these materials, especially their color saturation, does not meet the color gamut requirements of the BT2020 display and needs further improvement.

[0006] Therefore, developing a metal-iridium complex material with high luminous efficiency, low voltage, low evaporation temperature, high photo-electrochemical stability, high luminous efficiency, and long device life is a technical problem that needs to be solved.

[0007] In view of this, the present invention is proposed. Summary of the Invention

[0008] The purpose of this invention is to provide a metal iridium complex and an organic electroluminescent device.

[0009] This invention is implemented as follows:

[0010] In a first aspect, the present invention provides a metallic iridium complex with the general structural formula (La)₂IrLb, as shown in Formula I:

[0011] ;

[0012] In La, ring A and ring B are each independently selected from one or more 5-6 membered rings that form a monocyclic or polycyclic fused ring, wherein the 5-6 membered ring is a carbon ring or a heterocyclic ring;

[0013] In La, R1 and R2 independently represent monosubstitution up to the maximum permissible substitution, and any two of R1 and R2 are joined or fused to form a ring; and at least one of R1 or R2 contains a II structure: The dashed line in Formula II indicates a direct bond with ring A or ring B;

[0014] X is selected from O, S, SiR'R" or GeR'R";

[0015] Y1 and Y2 are independently selected from SiR'R" or GeR'R" respectively;

[0016] R', R", R1, and R2 are each independently selected from hydrogen, deuterium, halogen, boron group, silyl group, germanyl group, cyano group, isonitrile group, thio group, sulfinyl group, sulfonyl group, phosphinyl group, selenyl group, substituted or unsubstituted C1-C10 alkyl group, substituted or unsubstituted C3-C10 cycloalkyl group, substituted or unsubstituted C3-C10 heterocycloalkyl group, substituted or unsubstituted dimethylpentyl group, substituted or unsubstituted aralkyl group, substituted or unsubstituted alkoxy group, substituted or unsubstituted aryloxy group, substituted or unsubstituted amino group, etc. The group may contain any one or combination of substituted or unsubstituted alkenyl, substituted or unsubstituted cycloalkenyl, substituted or unsubstituted alkynyl, substituted or unsubstituted aryl, substituted or unsubstituted N-heteroaryl, substituted or unsubstituted acyl, substituted or unsubstituted carboxyl, substituted or unsubstituted ether, or substituted or unsubstituted ester; any two adjacent R', R", R1, and R2 may be joined or fused together to form a ring; the hydrogen atoms in the groups R', R", R1, and R2 may be deuterated or unsubstituted.

[0017] In Lb, R3, R4, and R5 are independently selected from hydrogen, substituted or unsubstituted C1 atoms, respectively. Any one or combination of C10 alkyl, substituted or unsubstituted C3-C6 cycloalkyl, -D, -CD3, -CF3, -F, -CN, and the hydrogen atoms in the groups R3, R4, and R5 may be deuterated or undeuterated.

[0018] The substitution in the context of substituted or unsubstituted means substitution by a substituent selected from one or at least two of the following groups linked together: methyl, ethyl, propyl, butyl, pentyl, hexyl, cyclopropyl, cyclobutyl, cyclopentyl, dimethylcyclopentyl, cyclohexyl, silyl, germanyl, or the following structures, where * indicates a linking bond;

[0019] .

[0020] In a second aspect, the present invention provides an organic electroluminescent device comprising a metal iridium complex as described in any of the above embodiments.

[0021] The present invention has the following beneficial effects:

[0022] The organic electroluminescent device prepared by the metal iridium complex in this invention is formed by directly fused with any one of the ligands of siloxane, silthioalkyl, silgeranyl, or hexamethyltrisilane. This metal iridium complex improves the intermolecular spatial configuration, increases radiative transitions, reduces molecular stacking, and has good spatial torsion capability, thereby avoiding carrier migration. When used as a specific dopant material for the light-emitting layer in organic electroluminescent devices, it promotes electron injection and transport, regulates the conjugated structure and electron distribution, and optimizes the singlet state. The triplet energy level difference and the reverse intersystem crossing rate enhance spin-orbit coupling. By controlling the data matching energy levels of HOMO and LUMO, the wavelength of the metal iridium complex can be adjusted. It has a lower voltage and significantly improved power efficiency. It has advantages such as low evaporation temperature, high photochemical stability, high luminous efficiency, and long device life. Moreover, the preparation method provided in the embodiments of the invention is simple and produces high-purity products, which is suitable for industrial production. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1The image shows the hydrogen nuclear magnetic resonance spectrum of the iridium complex Z-1 prepared in Example 1 of this invention. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions indicated by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0026] This invention provides a metallic iridium complex with the general structural formula (La)₂IrLb, as shown in Formula I:

[0027] ;

[0028] In La, ring A and ring B are each independently selected from one or more 5-6 membered rings, which are either monocyclic or polycyclic fused rings, and the 5-6 membered rings are carbon rings or heterocyclic rings.

[0029] In La, R1 and R2 independently represent monosubstitution up to the maximum permissible substitution, and any two of R1 and R2 are joined or fused to form a ring; and at least one of R1 or R2 contains a II structure: The dashed line in Formula II indicates a direct bond with ring A or ring B;

[0030] X is selected from O, S, SiR'R" or GeR'R";

[0031] Y1 and Y2 are independently selected from SiR'R" or GeR'R" respectively;

[0032] R', R", R1, and R2 are each independently selected from hydrogen, deuterium, halogen, boron group, silyl group, germanyl group, cyano group, isonitrile group, thio group, sulfinyl group, sulfonyl group, phosphinyl group, selenyl group, substituted or unsubstituted C1-C10 alkyl group, substituted or unsubstituted C3-C10 cycloalkyl group, substituted or unsubstituted C3-C10 heterocycloalkyl group, substituted or unsubstituted dimethylpentyl group, substituted or unsubstituted aralkyl group, substituted or unsubstituted alkoxy group, substituted or unsubstituted aryloxy group, substituted or unsubstituted amino group, etc. The group may contain any one or combination of substituted or unsubstituted alkenyl, substituted or unsubstituted cycloalkenyl, substituted or unsubstituted alkynyl, substituted or unsubstituted aryl, substituted or unsubstituted N-heteroaryl, substituted or unsubstituted acyl, substituted or unsubstituted carboxyl, substituted or unsubstituted ether, or substituted or unsubstituted ester; any two adjacent R', R", R1, and R2 may be joined or fused together to form a ring; the hydrogen atoms in the groups R', R", R1, and R2 may be deuterated or unsubstituted.

[0033] In Lb, R3, R4, and R5 are independently selected from hydrogen, substituted or unsubstituted C1 atoms, respectively. Any one or combination of C10 alkyl, substituted or unsubstituted C3-C6 cycloalkyl, -D, -CD3, -CF3, -F, -CN, and the hydrogen atoms in the groups R3, R4, and R5 may be deuterated or undeuterated.

[0034] The substitution in the context of substituted or unsubstituted means substitution by a substituent selected from one or at least two of the following groups linked together: methyl, ethyl, propyl, butyl, pentyl, hexyl, cyclopropyl, cyclobutyl, cyclopentyl, dimethylcyclopentyl, cyclohexyl, silyl, germanyl, or the following structures, where * indicates a linking bond;

[0035] .

[0036] Preferably, the heterocyclic alkyl group is dimethylpentyl, and the N-heteroaryl group is pyridine or pyrimidine.

[0037] The metal iridium complex provided by this invention is formed by directly fused with any one of the ligands of siloxane, siloxane, silgermanyl, or hexamethyltrisilane. This improves the intermolecular spatial configuration, increases radiative transitions, reduces molecular stacking, and exhibits good spatial torsion capability. It also reduces the intermolecular bond angle, increases lifetime, and thus avoids carrier migration. When used as a specific dopant material for the light-emitting layer in organic electroluminescent devices, the wavelength of the metal iridium complex can be tuned, resulting in lower voltage and significantly improved power efficiency. It also has advantages such as low deposition temperature, high photochemical and electrochemical stability, high luminous efficiency, and long device lifetime. Furthermore, the preparation method of the metal iridium complex of this invention is simple, produces high-purity products, and is suitable for industrial production.

[0038] It should be noted that the phrase "from monosubstituted to the maximum permissible substitution" in "R1 and R2 independently represent monosubstituted to the maximum permissible substitution" means that the substitution sites corresponding to R1 and R2 can be connected to one, two, three, or more substituents, up to the maximum number allowed by the chemical structure at that site. The "maximum permissible substitution" here is determined by the structure of the parent compound: for example, if a carbon atom is saturated carbon (sp...). 3(Hybridization), with a maximum of 3 remaining bonding sites (if one bond is already attached to the parent skeleton), the upper limit for the number of substituents at that site is 3; if it is a carbon atom on an aromatic ring, mono- to penta-substituted substitutions are usually allowed (depending on the number of hydrogen atoms that can be substituted on the aromatic ring). "Independently" means that the number and type of substituents in R1 are completely unrelated to R2, and the two do not affect each other; if R1 or R2 is polysubstituted, the multiple substituents at the same substitution site are also independent of each other (for example, when R1 is disubstituted, the two substituents can be the same or different).

[0039] "Any two of R1 and R2 can join or fused to form a ring" means that different atoms within the R1 group, different atoms within the R2 group, or atoms between R1 and R2 can interact to form a ring, provided the bonding conditions are met. Joining to form a ring means that an atom on R1 is directly connected to an atom on R2 by a chemical bond, or connected by one or more bridging atoms (such as C, N, O, S, etc.), together forming a ring structure. This ring can be an aliphatic ring (such as cycloalkanes, heterocyclic alkanes) or an aromatic ring (such as benzene rings, heteroaromatic rings). Fusing to form a ring means that the groups corresponding to R1 or R2 themselves have a cyclic structure, and the two cyclic structures share an edge (two adjacent atoms) to form a fused ring system. For example, a benzene ring fused with a pyridine ring forms a quinoline ring.

[0040] In some cases, a pair of adjacent substituents may optionally join or fused into a ring. Preferred rings are five-, six-, or seven-membered carbon rings or heterocyclic rings, including both cases where a portion of the ring formed by the pair of substituents is saturated and a portion of the ring formed by the pair of substituents is unsaturated. As used herein, “adjacent” means that the two substituents involved may be adjacent to each other on the same ring, or on two neighboring rings having two closest available substitutable positions, provided that a stable fused ring system can be formed.

[0041] Cycle A is selected from imidazole, benzimidazole, pyridine, pyrimidine, pyrazole, quinoline, isoquinoline, thiophenepyridine, benzothiophenepyridine, isopyrimidine, benzoisoquinoline, naphthiophenepyridine and naphthiophenepyrimidine, benzene, pyridazine, pyrazine, triazine, imidazole-derived carbenes, pyrrole, oxazole, furan, thiophene, thiazole, triazole, naphthalene, quinazoline, benzofuran, and azazolinium. Benzofuran, benzoxazole, aza Benzoxazole, benzothiophene, aza Benzothiophene, benzothiazole, aza Benzothiazole, benzo[selenyl]phenanthrene, aza Benzo[selenide]phenanthrene, indene, and azirconium Indene, indole, and azirconium Indole, benzimidazole-derived carbene, aza Benzimidazole, aza Benzimidazole-derived carbene, naphtho Imidazole, aza Naphthylene Imidazole, Carbazole, Aza Carbazole, dibenzofuran, aza Dibenzofuran, phenanthrene[2,3] b] Benzofuran, dibenzothiophene, aza Dibenzothiophene, quinoxaline, phthalazine, phenanthrene, azirconium phenanthrene, anthracene, and azirmones Anthracene, phenanthrene, fluorene and aza A group composed of fluorene.

[0042] Ring B is selected from benzene, pyridine, carbazole, benzimidazole, benzothiophene, dibenzothiophene, benzofuran, dibenzofuran, dibenzofluorene, naphthalene, phenazine, anthracene, phenanthrene, furan, thiophene, selenophene, benzoselenophene, naphthobenzofuran, and benzofuranpyridine.

[0043] The structure of Formula II is as follows:

[0044] ,

[0045] In Equation II, the dashed lines indicate direct connection to ring A or ring B.

[0046] In this invention, La coordinates with metal Ir to form a 5- or 6-membered chelate ring; Ir coordinates with Lb; La optionally binds with Lb to form tridentate, tetradentate, pentadentate or hexadentate ligands.

[0047] The structural formula of La is as follows:

[0048] .

[0049] The structural formula of Lb is as follows:

[0050]

[0051] Where D represents deuterium.

[0052] The hydrogen in the above groups or substituents can be replaced with deuterium.

[0053] Furthermore, the metallic iridium complex is selected from any of the following structures, but is not limited thereto:

[0054] .

[0055] It should be noted that only some specific structural forms have been listed above. However, this series of metal iridium complexes is not limited to the molecular structures mentioned above. Other specific molecular structures can be obtained by simply changing some simple groups and their substituted groups and substitution positions. These will not be elaborated on here.

[0056] The aforementioned iridium complex can be widely used in the preparation of organic electroluminescent devices. Correspondingly, the present invention also provides an organic electroluminescent device comprising the aforementioned iridium complex.

[0057] An organic electroluminescent device includes: a first electrode, a second electrode, and an organic layer disposed between the first electrode and the second electrode. The organic layer includes a light-emitting layer, which includes a metal iridium complex.

[0058] The light-emitting layer comprises a host material and a dopant material, wherein the dopant material is a metallic iridium complex, and the mass ratio of the host material to the dopant material is 90:10 to 99.5:0.5. For example, 90:10, 91:9, 92:8, 93:7, 94:6, 95:5, 96:4, 97:3, 98:2, or 99:1.

[0059] In this invention, the iridium complex exists in a single form or mixed with other substances in the organic layer.

[0060] Preferably, the organic layer further includes one or a combination of at least two of the following: a hole injection layer, a hole transport layer, a layer that has both hole injection and hole transport functions, an electron blocking layer, a hole blocking layer, an electron transport layer, an electron injection layer, and a layer that has both electron transport and electron injection functions.

[0061] The features and performance of the present invention will be further described in detail below with reference to embodiments. Those skilled in the art should understand that the embodiments are merely illustrative of the invention and should not be construed as limiting the invention.

[0062] Additionally, it should be noted that the values ​​given in the following embodiments are as accurate as possible. However, those skilled in the art will understand that due to unavoidable measurement errors and experimental issues, each number should be understood as an approximation rather than an absolutely accurate value.

[0063] Example 1

[0064] This embodiment provides a metallic iridium complex Z-1, whose structural formula is as follows: .

[0065] Its preparation method includes the following steps:

[0066] S1. Under nitrogen protection, take 1,3-dibromo-tetramethyldisiloxane (1 eq, CAS: 5290-08-4), K3PO4·3H2O (3 eq) were added to the reaction system, 1,4-dioxane was added, and DBA palladium (tris(dibenzylacetone)dipalladium, 0.01 eq) and S-Phos (2-dicyclohexylphosphine-2',6'-dimethoxybiphenyl, 0.1 eq) were added in three batches every 1 hour. After the addition was complete, the mixture was refluxed at 100°C for 24 h under nitrogen protection, then cooled to 25°C and concentrated under reduced pressure. The crude product was then subjected to column chromatography (200-300 mesh, 500 g) to remove impurities. The developing solvent was EA (ethyl acetate):PE (petroleum ether) in a volume ratio of 1:15. The receiving liquid was vortexed until no liquid flowed out and dried under vacuum to obtain intermediate 1 of the compound shown, with a yield of 91.7%.

[0067] The reaction formula is as follows:

[0068] .

[0069] S2. Under nitrogen protection, intermediate 1 (1 eq) and anhydrous potassium carbonate (3 eq) were added to the reaction system, along with toluene, anhydrous ethanol, and purified water. Under nitrogen protection, Pd(PPh3)4 (tetra(triphenylphosphine)palladium, 0.015 eq) was added. 2,3-dibromo-6-chloroaniline (1 eq, CAS: 1692746-63-6) was added in three batches every hour. After the addition was complete, the mixture was refluxed at 70°C for 24 hours under nitrogen protection, then cooled to 25°C. After the reaction cooled, the mixture was extracted with ethyl acetate, washed three times with saturated brine, dried over anhydrous magnesium sulfate, and concentrated under reduced pressure. The crude product was then subjected to column chromatography (200-300 mesh, 500 g) to remove impurities. The developing solvent was EA:PE (volume ratio) = 1:10. The receiving liquid was vortexed until no liquid flowed out, and then dried under vacuum to obtain intermediate 2 of the compound shown, with a yield of 91.7%.

[0070] The reaction formula is as follows:

[0071] .

[0072] S3. Under nitrogen protection, 2-bromo-4-chloro-3-methylthiopyridine (1 eq) and anhydrous potassium carbonate (3 eq) were added to the reaction system, along with toluene, anhydrous ethanol, and purified water. Under nitrogen protection, Pd(PPh3)4 (tetra(triphenylphosphine)palladium, 0.015 eq) was added. 2-Naphthoboric acid (1 eq, CAS: 32316-92-0) was added in three batches every hour. After the addition was complete, the mixture was refluxed at 70°C for 24 hours under nitrogen protection, then cooled to 25°C. After the reaction cooled, the mixture was extracted with ethyl acetate, washed three times with saturated brine, dried over anhydrous magnesium sulfate, and concentrated under reduced pressure. The crude product was then subjected to column chromatography (200-300 mesh, 500 g) to remove impurities. The developing solvent was EA:PE (volume ratio) = 1:15. The receiving liquid was vortexed until no liquid flowed out, and then dried under vacuum to obtain intermediate 3 of the compound shown, with a yield of 51.6%.

[0073] The reaction formula is as follows:

[0074] .

[0075] S4. Under nitrogen protection, intermediate 3 (1 eq) and K3PO4·3H2O (3 eq) were added to the reaction system. 1,4-Dioxane was added, followed by DBA palladium (tris(dibenzylacetone)dipalladium, 0.01 eq) and S-Phos (2-dicyclohexylphosphine-2',6'-dimethoxybiphenyl, 0.1 eq) in three batches every 1 hour. Pinacol diboronic acid ester (2 eq, CAS:73183-34-3) was added in three batches every 1 hour. After the addition was complete, the mixture was refluxed at 100°C for 24 h under nitrogen protection, then cooled to 25°C and concentrated under reduced pressure. The crude product was then subjected to column chromatography (200-300 mesh, 500 g) to remove impurities. The developing solvent was EA (ethyl acetate):PE (petroleum ether) in a volume ratio of 1:12. The receiving liquid was vortexed until no liquid flowed out and dried under vacuum to obtain intermediate 4 of the compound shown, with a yield of 93.5%.

[0076] The reaction formula is as follows:

[0077] .

[0078] S5. Under nitrogen protection, intermediate 4 (1 eq) and anhydrous potassium carbonate (3 eq) were added to the reaction system, along with toluene, anhydrous ethanol, and purified water. Under nitrogen protection, Pd(PPh3)4 (tetra(triphenylphosphine)palladium, 0.015 eq) was added. Intermediate 2 (1 eq) was added in three batches every hour. After the addition was complete, the mixture was refluxed at 70°C for 24 hours under nitrogen protection, then cooled to 25°C. After the reaction cooled, the mixture was extracted with ethyl acetate, washed three times with saturated brine, dried over anhydrous magnesium sulfate, and concentrated under reduced pressure. The crude product was then subjected to column chromatography (200-300 mesh, 500 g) to remove impurities. The developing solvent was EA:PE (volume ratio) = 1:10. The receiving liquid was vortexed until no liquid flowed out, and then dried under vacuum to obtain intermediate 5 of the compound shown, with a yield of 66.8%.

[0079] The reaction formula is as follows:

[0080] .

[0081] S6. Under nitrogen protection, take intermediate 5 (1 eq), add tetrahydrofuran and glacial acetic acid, stir at -10℃ for 10 minutes, add tert-butyl nitrite under nitrogen protection, react at -10℃ for 2 hours, then restore to room temperature for 2 hours. After the reaction is complete, dilute with water, and column chromatography (200-300 mesh, 500 g) is used to remove impurities. The developing solvent EA:PE volume ratio is 1:20. Rotate the receiving liquid until no liquid flows out, and dry under vacuum to obtain intermediate 6 of the compound shown, with a yield of 49.6%.

[0082] The reaction formula is as follows:

[0083] .

[0084] S7. Under nitrogen protection, intermediate 6 (2.5 eq) and IrCl3·3H2O (1 eq) were added to the reaction system, and a mixed solution of ethylene glycol ethyl ether and purified water was added. The mixture was refluxed at 120°C for 24 h under nitrogen protection, and then cooled to room temperature. A precipitate was formed. The precipitate was filtered, washed sequentially with water, anhydrous ethanol, and petroleum ether, and dried at 50°C for at least 10 h to obtain bridged ligand intermediate 7 with a yield of 53.0%.

[0085] The reaction formula is as follows:

[0086] .

[0087] S8. Under nitrogen protection, take intermediate 7 (1 eq), add anhydrous potassium carbonate (10 eq), then add ethylene glycol ethyl ether to the system, replace the nitrogen three times, add 3,7-diethylnon-4,6-dione (CAS: 872802-98-7, 2.5 eq) under nitrogen protection, reflux at 120°C for 24 h, cool, filter, wash with alcohol, dry at 50°C for at least 10 h, use dichloromethane as solvent, use silica gel column chromatography, concentrate the filtrate to precipitate the solid, and give the final compound Z-1 (11.78 g, yield 59.6%).

[0088] The reaction formula is as follows:

[0089]

[0090] HPLC purity: greater than 99.5%; MS (ESI, m / Z): [M+H]+: 1284.41, its 1H NMR spectrum is as follows: Figure 1 As shown.

[0091] In addition, it should be noted that other compounds of the present invention can be obtained by referring to the synthesis methods of the examples listed above, so they will not be listed one by one here.

[0092] Device Example 1

[0093] Organic electroluminescent devices were fabricated using the iridium complex Z-1 prepared in Example 1. The specific method is as follows:

[0094] An ITO glass substrate with a coating thickness of 1500 Å was rinsed three times in distilled water, ultrasonically cleaned for 30 minutes, and then rinsed three times with distilled water, ultrasonically cleaned for 30 minutes each time. After the distilled water rinsing, it was ultrasonically cleaned in sequence with solvents such as isopropanol, acetone, and methanol, dried, and transferred to a plasma cleaner. The ITO glass substrate was then cleaned for 5 minutes and sent to a vapor deposition machine. Under vacuum conditions, the standard pressure was set to 1 × 10⁻⁶. -6 Subsequently, an organic layer was formed on the ITO glass substrate in the order of CuPc (200Å), NPB (400Å), CBP+ iridium complex Z-1 (200Å), Alq3 (300Å), LiF (5Å), and Al (1000Å).

[0095] Among them, CBP+ metallic iridium complex Z-1 is represented as CBP doped with 5% (by mass) metallic iridium complex Z-1 and then vapor-deposited.

[0096] The structural formulas of CuPc, NPB, CBP, and Alq3 used in the device embodiments are as follows:

[0097] Device Examples 2-25

[0098] The method described in Device Example 1 is the same as above, except that the doping material compound Z-1 is used to replace Z-9, Z-19, Z-23, Z-58, Z-79, Z-101, Z-145, Z-167, Z-174, Z-207, Z-256, Z-271, Z-312, Z-342, Z-357, Z-414, Z-431, Z-465, Z-481, Z-504, Z-520, Z-554, and Z-586 respectively. The organic electroluminescent device is then prepared using the same method as in Device Example 1.

[0099] Device Comparison Examples 1-6

[0100] Organic electroluminescent devices were prepared using the same method as in Device Example 1, except that the dopant compound Z-1 in Example 1 was replaced with compounds shown in Comparative Examples 1, 2, 3, 4, 5, and 6, respectively. The specific structures are as follows:

[0101] .

[0102] The driving voltage, luminous efficiency, and lifetime of the organic electroluminescent devices obtained from the above-described device embodiments and device comparative examples were characterized at a brightness of 3000 nits. The test results are shown in Table 1. The driving voltage, luminous efficiency, and lifetime are all characterized as relative values ​​between this example and device comparative example 1. The relative value is calculated by taking each data point of device comparative example 1 as 1, and then comparing other data with device comparative example 1, expressed as a percentage. The relative value is a comparison between numbers, usually expressed as a percentage or decimal, used to indicate the degree of change of one number relative to other numbers. Furthermore, in industrial applications, relative values ​​can also be used to measure the degree of change in production efficiency and to evaluate product quality and stability.

[0103] Table 1. Statistical table of device test data for different examples

[0104]

[0105] As can be seen from the structures of the above embodiments and comparative examples, this application directly fuses siloxane groups. Although the comparative examples also have siloxane groups, they are fused to a benzene ring, and the benzene ring is connected to another ring through a single bond. The data results of the embodiments and comparative examples are shown in Table 1. Under the same current, the organic electroluminescent device prepared by the metal iridium complex in this invention generates a metal iridium complex by directly fusing any of the ligands of siloxane, silylsulfane, silaniumgeryl, and hexamethyltrisilane. This improves the intermolecular spatial configuration, increases radiative transitions, reduces molecular stacking, and has better spatial torsion ability, thereby avoiding carrier migration. When used as a specific dopant material for the light-emitting layer and applied to organic electroluminescent devices, the wavelength of the metal iridium complex can be adjusted, resulting in a lower voltage and significantly improved power efficiency. It also has advantages such as low evaporation temperature, high photochemical and electrochemical stability, high luminous efficiency, and long device life. Furthermore, the preparation method provided by the embodiments of the invention is simple, and the prepared product has high purity, making it suitable for industrial production.

[0106] Specifically, taking compound Z-1 as an example, its La-containing heteroaromatic rings (containing Si, S, and N) introduce siloxane groups, with silicon simultaneously connecting to three carbons. These siloxane groups fuse with thienopyridine-type heteroaromatic rings to form highly sterically hindered groups. Furthermore, the heteroaromatic rings themselves exhibit non-planar / twisted configurations, disrupting the coplanarity of the molecule and inhibiting intermolecular stacking. After the La heteroaromatic rings coordinate with Ir, steric hindrance occurs through the torsion of CN and CS bonds. Simultaneously, Lb utilizes the oxygen atom of the ester group to form a coordinate bond with Ir, while the double-bond conjugated system of the alkenyl group participates in electron delocalization. The isopropyl group further increases the molecular volume, making close molecular stacking difficult. Reduced intermolecular stacking avoids unnecessary migration of charge carriers (electrons / holes) (reducing non-radiative recombination) and lowers the leakage current of the device. The highly conjugated system of compound Z-1 is conducive to increasing radiative transitions and improving luminescence efficiency. The heteroatoms (N, S) of the ligands can optimize the hole / electron transport capability of the molecule, making the injection of electrons and holes in the luminescent layer more balanced, reducing "charge accumulation", and thus reducing the driving voltage of the device. Ultimately, it achieves low voltage, high luminescence efficiency and high stability, making it suitable as a doping material for the luminescent layer of organic electroluminescent devices.

[0107] This invention illustrates the iridium metal complex, its preparation method, and the organic electroluminescent device through the above embodiments. However, this invention is not limited to the above embodiments, meaning that it does not necessarily depend on the above embodiments for implementation. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of the raw materials used, additions of auxiliary components, selection of specific methods, etc., all modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention, fall within the protection and disclosure scope of this invention.

Claims

1. A metallic iridium complex, characterized in that, Its general structural formula is (La)2IrLb, The structural formula of La is as follows: ； The structural formula of Lb is as follows: ； Where D represents deuterium; Both La and Lb are coordinated with Ir through the dashed coordinate bond in the structural formula.

2. The iridium complex according to claim 1, characterized in that, The metallic iridium complex is selected from any of the following structures: 。 3. An organic electroluminescent device, characterized in that, The organic electroluminescent device comprises the metallic iridium complex as described in any one of claims 1-2.

4. The organic electroluminescent device according to claim 3, characterized in that, The organic electroluminescent device includes: a first electrode, a second electrode, and an organic layer disposed between the first electrode and the second electrode, wherein the organic layer includes a light-emitting layer, and the light-emitting layer includes the metal iridium complex.

5. The organic electroluminescent device according to claim 4, characterized in that, The light-emitting layer comprises a host material and a dopant material, wherein the dopant material is the metal iridium complex, and the mass ratio of the host material to the dopant material is 90:10 to 99.5:0.5.

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