Metal complex and application thereof

Abstract

The invention relates to a metal complex and application thereof. The metal complex disclosed by the invention comprises a structure as shown in a formula (I). When the metal complex provided by the invention is applied to the organic electroluminescent device, especially in a blue light emission region, the organic electroluminescent device shows enhanced phosphorescence quantum yield, and is good in luminescence stability and high in luminescence efficiency. # imgabs0 #

Description

Technical Field

[0001] The present invention belongs to the technical field of luminescent materials, and particularly relates to a metal complex and its application. Background Art

[0002] OLED (organic light-emitting diode) utilizes an organic thin film that emits light when a voltage is applied to the device. OLED is becoming an increasingly concerned technology for applications such as flat panel displays, lighting, and backlighting.

[0003] One application of phosphorescent emission molecules is full-color displays. Industry standards for such displays require pixels suitable for emitting specific colors. Specifically, these standards require saturated red, green, and blue pixels. Currently, red and green phosphorescent materials with a luminous efficiency of 100% are used in OLEDs of various sizes. Although a variety of blue light materials have been widely researched and developed, so far no blue phosphorescent material has been commercialized. There are many dissipation pathways for triplet excitons in phosphorescent materials, such as non-radiative transitions, delayed fluorescence, triplet-triplet annihilation, quenching by oxygen and water vapor, etc., which seriously affect the improvement of phosphorescent performance. It has been found that crystal engineering can utilize strong intermolecular interactions to effectively inhibit non-radiative transitions of triplet excitons, and because of its dense molecular packing, it can reduce the quenching of triplet excitons by oxygen, water vapor, etc., which is an effective way to achieve high-efficiency room-temperature phosphorescence. However, in the crystal aggregate state, intermolecular π-π stacking easily leads to triplet-triplet annihilation, dissipating a large amount of triplet excitons and affecting the improvement of phosphorescent efficiency; and π-π stacking will increase the intermolecular conjugation degree and cause a red shift in luminescence, making it difficult to achieve blue phosphorescence. Therefore, how to construct long-lived and high-efficiency blue phosphorescence is still one of the challenges faced by the field of organic phosphorescent materials. Summary of the Invention

[0004] To solve the above problems existing in the prior art, the present invention provides a metal complex and its application. When the metal complex is used in an OLED, especially in the blue light emission region, it exhibits an enhanced phosphorescence quantum yield and is suitable as an emitter material in OLED applications.

[0005] In a first aspect, the present invention provides a metal complex, which includes the structure shown in formula (I):

[0006]

[0007] Wherein, ring A, ring B, ring C, and ring D are each a 5-membered carbon ring, 5-membered heterocyclic ring, 6-membered carbon ring, or 6-membered heterocyclic ring;

[0008] M represents a metal element with an atomic weight greater than 40;

[0009] X1 to X 7 each independently selected from C, CH or N;

[0010] R 1 , R 2 , R 5 , R 6 each represents mono-substituted or multi-substituted to saturated substitution, or unsubstituted;

[0011] R 3 , R 4 each represents mono-substituted or di-substituted;

[0012] L 1 selected from a single bond, O, S, S=O, SO2, Se, NR 7 , PR 7 , R 7 P=O, CR 7 R 8 , C=O, SiR 7 R 8 , GeR 7 R 8 or BR 7 ;

[0013] L 2 selected from O, S, S=O, SO2, Se, NR 7 , PR 7 , R 7 P=O, CR 7 R 8 , C=O, SiR 7 R 8 , GeR 7 R 8 or BR 7 ;

[0014] R 1 to R 8 each independently selected from hydrogen or the group consisting of: hydrogen, deuterium, halogen atom, nitrile group, acyl group, carboxyl group, ether group, ester group, isonitrile group, sulfur group, selenoalkyl group, sulfinyl group, sulfonyl group, phosphino group, C1-C 40 (such as C2, C3, C4, C5, C6, C7, C8, C9, C 10 , C 11 , C 12 , C 13 , C 14 , C 15 , C 16 , C 17 , C 18 , C 19 , C 20 , C 23, C 25 , C 27 , C 30 , C 33 , C 35 or C 37 and so on) linear alkyl groups, C1 - C 40 (such as C2, C3, C4, C5, C6, C7, C8, C9, C 10 , C 11 , C 12 , C 13 , C 14 , C 15 , C 16 , C 17 , C 18 , C 19 , C 20 , C 23 , C 25 , C 27 , C 30 , C 33 , C 35 or C 37 and so on) linear heteroalkyl groups, C3 - C 40 (such as C4, C5, C6, C7, C8, C9, C 10 , C 11 , C 12 , C 13 , C 14 , C 15 , C 16 , C 17 , C 18 , C 19 , C 20 , C 23 , C 25 , C 27 , C 30 , C 33 , C 35 or C 37 and so on) branched or cyclic alkyl groups, C1 - C 40 (such as C2, C3, C4, C5, C6, C7, C8, C9, C 10 , C 11 , C 12 , C 13 , C 14 , C 15 , C 16 , C 17 , C 18 , C 19 , C 20 , C 23 , C 25 , C 27 , C30 , C 33 , C 35 or C 37 such as alkoxy groups of C6 - C 60 (such as C6, C7, C8, C9, C 10 , C 11 , C 12 , C 13 , C 14 , C 15 , C 16 , C 17 , C 18 , C 19 , C 20 , C 23 , C 25 , C 27 , C 30 , C 33 , C 35 , C 37 , C 40 , C 43 , C 45 , C 47 , C 50 , C 53 , C 55 or C 57 such as arylalkyl groups of C6 - C 60 (such as C6, C7, C8, C9, C 10 , C 11 , C 12 , C 13 , C 14 , C 15 , C 16 , C 17 , C 18 , C 19 , C 20 , C 23 , C 25 , C 27 , C 30 , C 33 , C 35 , C 37 , C 40 , C 43 , C 45 , C 47 , C 50 , C 53 , C 55 or C 57 such as aryloxy groups of C6 - C 60 (such as C6, C7, C8, C9, C 10 , C 11 , C 12 , C13 , C 14 , C 15 , C 16 , C 17 , C 18 , C 19 , C 20 , C 23 , C 25 , C 27 , C 30 , C 33 , C 35 , C 37 , C 40 , C 43 , C 45 , C 47 , C 50 , C 53 , C 55 or C 57 etc.) arylamino group, C3 - C 40 silyl group, C2 - C 40 alkenyl group, C4 - C 40 cycloalkenyl group, C2 - C 40 heteroalkenyl group, C2 - C 40 (such as C2, C3, C4, C5, C6, C7, C8, C9, C 10 , C 11 , C 12 , C 13 , C 14 , C 15 , C 16 , C 17 , C 18 , C 19 , C 20 , C 23 , C 25 , C 27 , C 30 , C 33 , C 35 or C 37 etc.) alkynyl group, C6 - C 60 (such as C6, C7, C8, C9, C 10 , C 11 , C 12 , C 13 , C 14 , C 15 , C 16 , C 17 , C 18 , C 19 , C 20 , C 23 , C 25 , C 27 , C30 , C 33 , C 35 , C 37 , C 40 , C 43 , C 45 , C 47 , C 50 , C 53 , C 55 or C 57 etc.) aryl, C2-C 60 (such as C3, C4, C5, C6, C7, C8, C9, C 10 , C 11 , C 12 , C 13 , C 14 , C 15 , C 16 , C 17 , C 18 , C 19 , C 20 , C 23 , C 25 , C 27 , C 30 , C 33 , C 35 , C 37 , C 40 , C 43 , C 45 , C 47 , C 50 , C 53 , C 55 or C 57 etc.) heteroaryl, any two or more adjacent R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 and R 8 may optionally be joined or fused to form a substituted or unsubstituted ring;

[0015] Optionally, the groups in R 1 ~R 8 are substituted by one or more substituents selected from deuterium, halogen atoms, cyano groups, C1-C6 straight-chain alkyl groups (such as methyl, ethyl, n-propyl or n-butyl), C3-C6 branched-chain alkyl groups (such as isopropyl, isobutyl or tert-butyl).

[0016] Preferably, the ring A is a 5-membered heteroaromatic ring.

[0017] Preferably, the ring B is a 6-membered aromatic ring or a 6-membered heteroaromatic ring.

[0018] Preferably, the ring C is a 5-membered heteroaromatic ring, a 6-membered aromatic ring or a 6-membered heteroaromatic ring.

[0019] In some embodiments, the heteroatoms in the heterocyclic and heteroaromatic rings are N, O or S.

[0020] In some embodiments, the metal complex is selected from the group consisting of:

[0021]

[0022]

[0023]

[0024] wherein Y independently represents O, S or NR 9 ;

[0025] R 1 ~R 6 、L 1 、L 2 are defined the same as in formula (I) above;

[0026] R 9 is selected from the group consisting of: hydrogen, C1-C 40 (such as C2, C3, C4, C5, C6, C7, C8, C9, C 10 、C 11 、C 12 、C 13 、C 14 、C 15 、C 16 、C 17 、C 18 、C 19 、C 20 、C 23 、C 25 、C 27 、C 30 、C 33 、C 35 or C 37 etc.) linear alkyl groups, C1-C 40 (such as C2, C3, C4, C5, C6, C7, C8, C9, C 10 、C 11 、C 12 、C 13 、C 14 、C 15 、C 16 、C 17 、C 18 、C 19 、C20 , C 23 , C 25 , C 27 , C 30 , C 33 , C 35 or C 37 etc.) linear heteroalkyl, C3 - C 40 (e.g., C4, C5, C6, C7, C8, C9, C 10 , C 11 , C 12 , C 13 , C 14 , C 15 , C 16 , C 17 , C 18 , C 19 , C 20 , C 23 , C 25 , C 27 , C 30 , C 33 , C 35 or C 37 etc.) branched or cyclic alkyl, C6 - C 60 (e.g., C6, C7, C8, C9, C 10 , C 11 , C 12 , C 13 , C 14 , C 15 , C 16 , C 17 , C 18 , C 19 , C 20 , C 23 , C 25 , C 27 , C 30 , C 33 , C 35 , C 37 , C 40 , C 43 , C 45 , C 47 , C 50 , C 53 , C 55 or C 57 etc.) arylalkyl, C3 - C 40 (e.g., C4, C5, C6, C7, C8, C9, C 10 , C 11 , C 12 , C 13 , C 14 , C 15, C 16 , C 17 , C 18 , C 19 , C 20 , C 23 , C 25 , C 27 , C 30 , C 33 , C 35 or C 37 etc.) silyl group, C2 - C 40 (such as C3, C4, C5, C6, C7, C8, C9, C 10 , C 11 , C 12 , C 13 , C 14 , C 15 , C 16 , C 17 , C 18 , C 19 , C 20 , C 23 , C 25 , C 27 , C 30 , C 33 , C 35 or C 37 etc.) alkenyl group, C4 - C 40 (such as C5, C6, C7, C8, C9, C 10 , C 11 , C 12 , C 13 , C 14 , C 15 , C 16 , C 17 , C 18 , C 19 , C 20 , C 23 , C 25 , C 27 , C 30 , C 33 , C 35 or C 37 etc.) cycloalkenyl group, C2 - C 40 (such as C3, C4, C5, C6, C7, C8, C9, C 10 , C 11 , C 12 , C 13 , C 14 , C 15 , C 16 , C 17 , C 18 , C19 , C 20 , C 23 , C 25 , C 27 , C 30 , C 33 , C 35 or C 37 and other heteroalkenyl groups of C, C2-C 40 (such as C3, C4, C5, C6, C7, C8, C9, C 10 , C 11 , C 12 , C 13 , C 14 , C 15 , C 16 , C 17 , C 18 , C 19 , C 20 , C 23 , C 25 , C 27 , C 30 , C 33 , C 35 or C 37 and other alkynyl groups of C, C6-C 60 (such as C6, C7, C8, C9, C 10 , C 11 , C 12 , C 13 , C 14 , C 15 , C 16 , C 17 , C 18 , C 19 , C 20 , C 23 , C 25 , C 27 , C 30 , C 33 , C 35 , C 37 , C 40 , C 43 , C 45 , C 47 , C 50 , C 53 , C 55 or C 57 and other aryl groups of C, C2-C 60 (such as C3, C4, C5, C6, C7, C8, C9, C 10 , C 11 , C 12 , C 13 , C 14 , C15 , C 16 , C 17 , C 18 , C 19 , C 20 , C 23 , C 25 , C 27 , C 30 , C 33 , C 35 , C 37 , C 40 , C 43 , C 45 , C 47 , C 50 , C 53 , C 55 or C 57 etc.) of heteroaryl.

[0027] Preferably, the R 9 is selected from C1-C 40 linear alkyl, C1-C 40 linear heteroalkyl, C3-C 40 branched or cyclic alkyl, C6-C 60 aryl, C2-C 60 heteroaryl and combinations thereof.

[0028] Preferably, the M is selected from Ir, Pt, Pd, Ru, Rh, Os, Au, Cu, Ni, Co, Ga or Ge. Further, the M is selected from Pt or Pd. Most preferably, the M is Pt.

[0029] Preferably, the L 1 is selected from a single bond, O, S, NR 7 , CR 7 R 8 or BR 7 .

[0030] Preferably, the L 2 is selected from O, S, NR 7 , CR 7 R 8 , or BR 7 .

[0031] Preferably, the ring C is selected from C6-C 60 aryl or C2-C 60 heteroaryl.

[0032] In some embodiments, the ring C is selected from the group consisting of the following groups:

[0033]

[0034] Among them, two adjacent "*" represent the bonding positions with L 2 and B;

[0035] G is selected from O, S, Se, NR 10 , SiR 10 R 11 , or GeR 10 R 11 ;

[0036] R 10 , R 11 are each independently selected from the group consisting of R A1 ~R A30 , R B1 ~R B195 , R C1 ~R C80 .

[0037] Furthermore, the R 1 , R 2 , R 3 , R 4 , R 5 , R 6 are each independently selected from the group consisting of a hydrogen atom, a deuterium atom, fluorine, a cyano group, an isocyano group, R A1 ~R A30 , R B1 ~R B195 , R C1 ~R C80 .

[0038] Furthermore, the R 7 , R 8 , R 9 are each independently selected from the group consisting of R A1 ~R A30 , R B1 ~R B195 , R C1 ~R C80 .

[0039] In this article, the structural formula represented by R A1 ~R A30 is as shown below:

[0040]

[0041]

[0042] R B1 ~R B195 is as shown below:

[0043]

[0044]

[0045]

[0046]

[0047]

[0048] R C1 ~R C80 The structure shown is as follows:

[0049]

[0050]

[0051] Each hydrogen atom in each substituent can be partially or completely replaced by a deuterium atom. In some embodiments, the metal complex is selected from the group consisting of,

[0052]

[0053] wherein ring C is selected from aryl groups of C6 - C 12 and is preferably More preferably, ring C is wherein two adjacent "*" represent the bonding positions to L 2 and B;

[0054] L 1 is selected from a single bond, O, NR 7 , R 7 has the definition described in the present invention. Preferably, R 1 in L 7 is selected from hydrogen, deuterium, a halogen atom, a nitrile group, a straight-chain alkyl group of C1 - C6, a branched-chain alkyl group of C3 - C6, a straight-chain alkoxy group of C1 - C6, a branched-chain alkoxy group of C3 - C6, an aryl group of C6 - C 12 . Optionally, R 7 is fused with an adjacent benzene ring (preferably a benzene ring substituted by R 2 ) to form a heteroaryl group of C6 - C 15 (such as The dotted line represents the fusion position with the benzene ring), and the R 7 group is optionally substituted by one or more substituents selected from deuterium, a halogen atom, a nitrile group, a straight-chain alkyl group of C1 - C6, and a branched-chain alkyl group of C3 - C6;

[0055] L 2 is selected from O, S, CR 7 R 8 , NR 7 , R7 and R 8 has the definition described in the present invention. Preferably, L 2 in R 7 and R 8 are each independently selected from hydrogen, deuterium, a halogen atom, a nitrile group, a linear alkyl group having 1 to 6 carbon atoms, a branched alkyl group having 3 to 6 carbon atoms, a linear alkoxy group having 1 to 6 carbon atoms, a branched alkoxy group having 3 to 6 carbon atoms, an aryl group having 6 to C 12 ; R 7 and R 8 each group in is optionally substituted by one or more substituents selected from deuterium, a halogen atom, a nitrile group, a linear alkyl group having 1 to 6 carbon atoms, and a branched alkyl group having 3 to 6 carbon atoms; More preferably, R 7 and R 8 are each independently selected from deuterium, fluorine, chlorine, bromine, a nitrile group, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, deuterated methyl, fluoromethyl, deuterated ethyl, fluoroethyl, phenyl, naphthyl, tolyl, ethylphenyl, propylphenyl, tert-butylphenyl, deuterated phenyl, fluorophenyl;

[0056] Y each independently represents O, S or NR 9 , R 9 has the definition described in the present invention. Preferably, R 9 are each independently selected from hydrogen, deuterium, a halogen atom, a nitrile group, a linear alkyl group having 1 to 6 carbon atoms, a branched alkyl group having 3 to 6 carbon atoms, a linear alkoxy group having 1 to 6 carbon atoms, a branched alkoxy group having 3 to 6 carbon atoms, an aryl group having 6 to C 12 ; the R 9 group is optionally substituted by one or more substituents selected from deuterium, a halogen atom, a nitrile group, a linear alkyl group having 1 to 6 carbon atoms, and a branched alkyl group having 3 to 6 carbon atoms; More preferably, R 9 is selected from deuterium, fluorine, chlorine, bromine, a nitrile group, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, deuterated methyl, fluoromethyl, deuterated ethyl, fluoroethyl, phenyl, naphthyl, tolyl, ethylphenyl, propylphenyl, tert-butylphenyl, deuterated phenyl, fluorophenyl;

[0057] R 1 ~R 6 has the same definition as formula (I). Preferably, R 1 ~R 6 are each independently selected from the group consisting of R A1 ~R A30 , R B1 ~R B195 , R C1 ~R C80 .

[0058] In some embodiments, each R 1Independently selected from hydrogen, deuterium, a halogen atom, a nitrile group, a C1-C6 straight-chain alkyl group, a C3-C6 branched-chain alkyl group, a C1-C6 straight-chain alkoxy group, a C3-C6 branched-chain alkoxy group, a C6-C 12 aryl, a C2-C 10 heteroaryl, optionally, adjacent R 1 fused to form a C6-C 15 aryl, a C3-C 15 heteroaryl, each group in R 1 is optionally substituted by one or more substituents selected from deuterium, a halogen atom, a nitrile group, a C1-C6 straight-chain alkyl group, and a C3-C6 branched-chain alkyl group;

[0059] Preferably, R 1 is independently selected from deuterium, fluorine, chlorine, bromine, a nitrile group, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, deuterated methyl, fluorinated methyl, deuterated ethyl, fluorinated ethyl, phenyl, naphthyl, tolyl, ethylphenyl, propylphenyl, tert-butylphenyl, deuterated phenyl, and fluorinated phenyl;

[0060] Preferably, adjacent R 1 is fused to form the following ring structure: (The dotted line indicates the fusion position), wherein, Ra and Rb are each independently selected from hydrogen, deuterium, a halogen atom, a nitrile group, a C1-C6 straight-chain alkyl group, a C3-C6 branched-chain alkyl group, a C1-C6 straight-chain alkoxy group, a C3-C6 branched-chain alkoxy group, a C6-C 12 aryl, and each group in Ra and R b is optionally substituted by one or more substituents selected from deuterium, a halogen atom, a nitrile group, a C1-C6 straight-chain alkyl group, and a C3-C6 branched-chain alkyl group; More preferably, Ra and Rb are each independently selected from deuterium, fluorine, chlorine, bromine, a nitrile group, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, deuterated methyl, fluorinated methyl, deuterated ethyl, fluorinated ethyl, phenyl, naphthyl, tolyl, ethylphenyl, propylphenyl, tert-butylphenyl, deuterated phenyl, and fluorinated phenyl.

[0061] In some embodiments, R 2 , R 3 and R 4 are each independently selected from hydrogen, deuterium, a halogen atom, a nitrile group, a C1-C6 straight-chain alkyl group, a C3-C6 branched-chain alkyl group, a C1-C6 straight-chain alkoxy group, a C3-C6 branched-chain alkoxy group, a C6-C 12 aryl, and each group in R 2 , R 3 and R 4 is optionally substituted by one or more substituents selected from deuterium, a halogen atom, a nitrile group, a C1-C6 straight-chain alkyl group, and a C3-C6 branched-chain alkyl group; More preferably, R2 , R 3 and R 4 are each independently selected from deuterium, fluorine, chlorine, bromine, cyano, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, deuterated methyl, fluorinated methyl, deuterated ethyl, fluorinated ethyl, phenyl, naphthyl, tolyl, ethylphenyl, propylphenyl, tert-butylphenyl, deuterated phenyl, fluorinated phenyl.

[0062] In some embodiments, R 5 is selected from hydrogen, deuterium, a halogen atom, cyano, a C1-C6 straight-chain alkyl group, a C3-C6 branched-chain alkyl group, a C1-C6 straight-chain alkoxy group, a C3-C6 branched-chain alkoxy group, an aryl group having C6-C 12 , and each group in R 5 is optionally substituted with one or more substituents selected from deuterium, a halogen atom, cyano, a C1-C6 straight-chain alkyl group, a C3-C6 branched-chain alkyl group; more preferably, R 5 are each independently selected from deuterium, fluorine, chlorine, bromine, cyano, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, deuterated methyl, fluorinated methyl, deuterated ethyl, fluorinated ethyl, phenyl, naphthyl, tolyl, ethylphenyl, propylphenyl, tert-butylphenyl, deuterated phenyl, fluorinated phenyl.

[0063] In some embodiments, each R 6 is independently selected from hydrogen, deuterium, a halogen atom, cyano, a C1-C6 straight-chain alkyl group, a C3-C6 branched-chain alkyl group, a C1-C6 straight-chain alkoxy group, a C3-C6 branched-chain alkoxy group, an aryl group having C6-C 12 , a heteroaryl group having C2-C 10 . Optionally, adjacent Rs 6 are fused into an aryl group having C6-C 15 , a heteroaryl group having C3-C 15 , and each group in R 6 is optionally substituted with one or more substituents selected from deuterium, a halogen atom, cyano, a C1-C6 straight-chain alkyl group, a C3-C6 branched-chain alkyl group;

[0064] Preferably, R 6 is independently selected from deuterium, fluorine, chlorine, bromine, cyano, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, deuterated methyl, fluorinated methyl, deuterated ethyl, fluorinated ethyl, phenyl, naphthyl, tolyl, ethylphenyl, propylphenyl, tert-butylphenyl, deuterated phenyl, fluorinated phenyl;

[0065] Preferably, adjacent Rs 6 are fused into the following ring structures: (The dotted line indicates the fusion position).

[0066] In the substituted or unsubstituted ring formed by the binding of adjacent groups to each other in the present invention, the "ring" refers to a substituted or unsubstituted hydrocarbon ring or a substituted or unsubstituted heterocyclic ring. A fused ring refers to a fused aliphatic ring, a fused aromatic ring, a fused aliphatic heterocyclic ring, a fused aromatic heterocyclic ring, or a form composed of their combinations.

[0067] The 5-membered carbon ring described in the present invention is a monocyclic and polycyclic system having 5 carbon atoms. The polycyclic ring has two or more rings in which two carbons are shared by two adjacent rings, for example, the 5-membered carbon ring can be cyclopentane, cyclopentene, indane, indene, etc. The 5-membered heterocyclic ring refers to a 5-membered carbon ring containing at least one heteroatom, and the total number of heteroatoms and carbon atoms constituting the ring is 5. The heteroatoms include, but are not limited to, oxygen, sulfur, nitrogen, phosphorus, boron, silicon, or selenium. In many cases, oxygen, sulfur, or nitrogen is a preferred heteroatom. Non-limiting examples of the 5-membered heterocyclic ring include pyrazole, imidazole, oxazole, thiazole, triazole, oxadiazole, oxatriazole, dioxazole, thiadiazole, benzimidazole, pyridinoimidazole, benzoxazole, benzotriazole, etc.

[0068] The 6-membered carbon ring described in the present invention is a monocyclic and polycyclic system having 6 carbon atoms. Preferably, the 6-membered carbon ring refers to the aryl group described in the present invention. The 6-membered heterocyclic ring refers to a ring system in which the total number of heteroatoms and carbon atoms is 6. Preferably, the 6-membered heterocyclic ring refers to a 6-membered heteroaryl group, such as pyridine, pyridazine, pyrimidine, pyrazine, triazine, oxazine, oxathiazine, oxadiazine, quinoline, isoquinoline, cinnoline, quinazoline, quinoxaline, naphthyridine, phthalazine, pteridine, etc.

[0069] The "aryl group" according to the present invention refers to and includes a monocyclic aromatic hydrocarbon group and a polycyclic aromatic ring system. The polycyclic ring can have two or more rings in which two carbons are shared by two adjacent rings (the rings are "fused"), and at least one of the rings is an aromatic hydrocarbon group. For example, the other rings can be cycloalkyl, cycloalkenyl, aryl, heterocyclic, and / or heteroaryl. The preferred aryl group is an aryl group containing 6 to 30 carbon atoms, preferably 6 to 20 carbon atoms, more preferably 6 to 12 carbon atoms. Particularly preferred are aryl groups having six carbons, ten carbons, or twelve carbons. Suitable aryl groups include phenyl, biphenyl, terphenyl, triphenylene, tetraphenylene, naphthyl, anthryl, phenanthryl, fluorenyl, pyrenyl, perylenyl, azulenyl, and preferably phenyl, biphenyl, terphenyl, triphenylene, fluorenyl, and naphthyl. Additionally, the aryl group can be optionally substituted.

[0070] "Heteroaryl" in the sense of the present invention means and includes monocyclic aromatic groups and polycyclic aromatic ring systems comprising at least one heteroatom. Heteroatoms include, but are not limited to, oxygen, sulfur, nitrogen, phosphorus, boron, silicon or selenium. In many cases, oxygen, sulfur or nitrogen are preferred heteroatoms. The monocyclic heteroaromatic system is preferably a monocyclic ring having 5 or 6 ring atoms, and the ring may have one to six heteroatoms. The heteropolycyclic system may have two or more rings in which two atoms are shared by two adjacent rings (the rings are "fused"), where at least one of the rings is a heteroaryl, for example the other rings may be cycloalkyl, cycloalkenyl, aryl, heterocyclic and / or heteroaryl. The heteropolycyclic aromatic ring system may have one to six heteroatoms on each ring of the polycyclic aromatic ring system. Preferred heteroaryls are heteroaryls containing from three to thirty carbon atoms, preferably from three to twenty carbon atoms, more preferably from three to twelve carbon atoms. Suitable heteroaryls include dibenzothienyl, dibenzofuranyl, dibenzoselenophenyl, furyl, thienyl, benzofuranyl, benzothienyl, benzoselenophenyl, carbazolyl, indolocarbazolyl, pyridylindolyl, pyrrolodipyridyl, pyrazolyl, imidazolyl, triazolyl, oxazolyl, thiazolyl, oxadiazolyl, oxatriazolyl, dioxazolyl, thiadiazolyl, pyridyl, pyridazinyl, pyrimidinyl, pyrazinyl, triazinyl, oxazinyl, oxathiazinyl, oxadiazinyl, indolyl, benzimidazolyl, indazolyl, indoxazinyl, benzoxazolyl, benzisoxazolyl, benzothiazolyl, quinolinyl, isoquinolinyl, cinnolinyl, quinazolinyl, quinoxalinyl, naphthyridinyl, phthalazinyl, pteridinyl, xanthenyl, acridinyl, phenazinyl, phenothiazinyl, phenoxazinyl, benzofuranopyridyl, furanodipyridyl, benzothiophenopyridyl, thiophenodipyridyl, benzoselenophenopyridyl, selenophenodipyridyl, 1,2-azaborolyl, 1,3-azaborolyl, 1,4-azaborolyl, borazanyl and their nitrogen analogues, preferably dibenzothienyl, dibenzofuranyl, dibenzoselenophenyl, carbazolyl, indolocarbazolyl, imidazolyl, pyridyl, triazinyl, benzimidazolyl, 1,2-azaborolyl, 1,3-azaborolyl, 1,4-azaborolyl, borazanyl and their nitrogen analogues. Additionally, the heteroaryl may optionally be substituted.

[0071] For the purposes of the present invention, the alkyl group contains 1 to 40 carbon atoms and may be a straight-chain or branched alkyl group in which a single hydrogen atom or -CH2- group may also be substituted, and the alkenyl or alkynyl group contains at least two carbon atoms. As non-limiting examples, the alkyl, alkenyl or alkynyl group is preferably considered to refer to the following groups: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, 2-methylbutyl, n-pentyl, sec-pentyl, neopentyl, cyclopentyl, n-hexyl, neohexyl, cyclohexyl, n-heptyl, cycloheptyl, n-octyl, cyclooctyl, 2-ethylhexyl, cyclohexenyl, heptenyl, cycloheptenyl, octenyl, cyclooctenyl, ethynyl, propynyl, butynyl, pentynyl, hexynyl, heptynyl or octynyl.

[0072] Alkoxy groups preferably having 1 to 40 carbon atoms are considered to be methoxy, trifluoromethoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy, n-pentyloxy, sec-pentyloxy, 2-methylbutoxy, n-hexyloxy, cyclohexyloxy, n-heptyloxy, cycloheptyloxy, n-octyloxy, cyclooctyloxy, 2-ethylhexyloxy, pentafluoroethoxy and 2,2,2-trifluoroethoxy.

[0073] Heteroalkyl groups preferably having 1 to 40 carbon atoms are alkyl groups in which a single hydrogen atom or -CH2- group is replaced by an oxygen, sulfur or halogen atom, and are considered to be alkoxy, alkylthio, fluoroalkoxy, fluoroalkylthio, especially methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy, methylthio, ethylthio, n-propylthio, isopropylthio, n-butylthio, isobutylthio, sec-butylthio, tert-butylthio, trifluoromethylthio, trifluoromethoxy, pentafluoroethoxy, pentafluoroethylthio, 2,2,2-trifluoroethoxy, 2,2,2-trifluoroethylthio, vinyloxy, vinylthio, allyloxy, allylthio, butenylthio, butenyloxy, pentenyloxy, pentenylthio, cyclopentenoxy, cyclopentenylthio, hexenyloxy, hexenylthio, cyclohexenoxy, cyclohexenylthio, ethynyloxy, ethynylthio, propynyloxy, propynylthio, butynyloxy, butynylthio, pentynyloxy, pentynylthio, hexynyloxy, hexynylthio.

[0074] Generally, the cycloalkyl and cycloalkenyl groups according to the present invention may be cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cyclobutenyl, cyclopentenyl, cyclohexenyl, cycloheptyl, cycloheptenyl, in which one or more -CH2- groups may be replaced by the above groups; in addition, one or more hydrogen atoms may also be replaced by deuterium atoms, halogen atoms or nitrile groups.

[0075] The alkenyl or alkynyl group according to the present invention has 2 to 40 carbon atoms, and the alkenyl or alkynyl group in which a single hydrogen atom can be substituted is preferably vinyl, propenyl, butenyl, isobutenyl, styryl, stilbenyl, ethynyl, propynyl, butynyl, phenylacetylenyl; in addition, one or more hydrogen atoms can also be replaced by deuterium atoms, halogen atoms or nitrile groups.

[0076] The aryl or heteroaryl group according to the present invention particularly refers to a group derived from the following substances: phenyl, naphthyl, anthryl, benzanthryl, phenanthryl, pyrenyl, fluorenyl, perylenyl, fluoranthenyl, tetraphenyl, pentaphenyl, benzopyrenyl, biphenyl, azobenzene, terphenyl, triphenyl, quaterphenyl, fluorene, spirobifluorene, dihydrophenanthryl, triphenylene, dihydropyrenyl, tetrahydropyrenyl, cis- or trans-indeno[1,2-b]fluorene, cis- or trans-indeno[2,3-b]carbazole, cis- or trans-indolo[2,3-b]carbazole, trindene, isotrindene, spirotrindene, spiroisotrindene, furyl, benzofuryl, isobenzofuryl, dibenzofuryl, thienyl, benzothienyl, isobenzothienyl, dibenzothienyl, pyrrolyl, indolyl, isoindolyl, carbazolyl, pyridyl, quinolinyl, isoquinolinyl, acridinyl, phenanthridinyl, benzo[5,6]quinolinyl, benzo[6,7]quinolinyl, benzo[7,8]quinolinyl, phenothiazinyl, phenoxazinyl, pyrazolyl, indazolyl, imidazolyl, benzimidazolyl, naphthimidazolyl, phenanthrimidazolyl, pyridinimidazolyl, pyrazinimidazolyl, quinoxalinimidazolyl, oxazolyl, benzoxazolyl, naphthoxazolyl, anthroxazolyl, phenanthroxazolyl, isoxazolyl, 1,2-thiazolyl, 1,3-thiazolyl, benzothiazolyl, pyridazinyl, hexaazatriphenylene, benzopyridazinyl, pyrimidinyl, benzopyrimidinyl, quinoxalinyl, 1,5-diazaanthracenyl, 2,7-diazapyrenyl, 2,3-diazapyrenyl, 1,6-diazapyrenyl, 1,8-diazapyrenyl, 4,5-diazapyrenyl, 4,5,9,10-tetraazaperylenyl, pyrazinyl, phenazinyl, phenoxazinyl, phenothiazinyl, fluoranthen-9-one, naphthyridinyl, azacarbazolyl, benzocarbolinyl, carbolinyl, phenanthrolinyl, 1,2,3-triazolyl, 1,2,4-triazolyl, benzotriazolyl, 1,2,3-oxadiazolyl, 1,2,4-oxadiazolyl, 1,2,5-oxadiazolyl, 1,3,4-oxadiazolyl, 1,2,3-thiadiazolyl, 1,2,4-thiadiazolyl, 1,2,5-thiadiazolyl, 1,3,4-thiadiazolyl, 1,3,5-triazinyl, 1,2,4-triazinyl, 1,2,3-triazinyl, tetrazolyl, 1,2,4,5-tetrazinyl, 1,2,3,4-tetrazinyl, 1,2,3,5-tetrazinyl, purinyl, pteridinyl, indolizinyl, quinazolinyl, benzothiadiazolyl or a group derived from a combination of these systems.

[0077] "Acyl" in the sense of the present invention refers to a substituted carbonyl group (COR).

[0078] "Ester group" in the sense of the present invention refers to a substituted oxycarbonyl group (-OCOR or CO2R).

[0079] "Ether group" in the sense of the present invention refers to an -OR group.

[0080] The "thio group" or "thioether" described herein is used interchangeably and refers to an -SR group.

[0081] "Sulfinyl group" in the sense of the present invention refers to an -SOR group.

[0082] "Sulfonyl group" in the sense of the present invention refers to an -SO2R group.

[0083] "Phosphino group" in the sense of the present invention refers to a -PR3 group, where each R can be the same or different.

[0084] "Silyl group" in the sense of the present invention refers to a -SiR3 group, where each R can be the same or different.

[0085] Each of the above Rs is preferably selected from the group consisting of alkyl, cycloalkyl, aryl, and heteroaryl.

[0086] The aryloxy used in the present invention refers to a monovalent functional group represented by R'O - wherein R' is an aryl group having 6 to 60 carbon atoms. Non-limiting examples of such aryloxy groups include phenoxy, naphthoxy, biphenyloxy, etc.

[0087] The alkylsilyl used in the present invention refers to a silyl group substituted with an alkyl group having 1 to 40 carbon atoms, and the number of carbon atoms constituting the alkylsilyl is at least 3. Non-limiting examples of alkylsilyl groups include trimethylsilyl, triethylsilyl, etc. Arylsilyl refers to a silyl group substituted with an aryl group having 6 to 60 carbon atoms.

[0088] The arylphosphino used in the present invention refers to a diarylphosphino group substituted with an aryl group having 6 to 60 carbon atoms. Non-limiting examples of arylphosphino groups include diphenylphosphino, bis(4-trimethylsilylphenyl)phosphino, etc. Aryloxyphosphino is the arylphosphino group in which the phosphorus atom is oxidized to the highest valence state.

[0089] The arylboron used in the present invention refers to a diarylboron group substituted with an aryl group having 6 to 60 carbon atoms. Non-limiting examples of arylboron groups include diphenylboron, bis(2,4,6-trimethylphenyl)boron, etc. Alkylboron refers to a dialkylboron group substituted with an alkyl group having 1 to 40 carbon atoms. Non-limiting examples of alkylboron groups include di-tert-butylboron, diisobutylboron, etc.

[0090] As used interchangeably herein, "halogen", "halo", "halo atom", and "halo group" refer to fluorine, chlorine, bromine, or iodine.

[0091] As used herein, "a combination thereof" or "a group" means that one or more members of a list of applicable members are combined to form a known or chemically stable arrangement that can be envisioned by one of ordinary skill in the art from the applicable list. For example, an alkyl group and deuterium can be combined to form a partially or fully deuterated alkyl group; a halogen and an alkyl group can be combined to form a haloalkyl substituent such as trifluoromethyl, etc.; and a halogen, an alkyl group, and an aryl group can be combined to form a haloarylalkyl group.

[0092] As used herein, the term "substituted or unsubstituted" means being substituted or unsubstituted by one or more substituents selected from hydrogen, deuterium, halo atom, hydroxy group, nitrile group, nitro group, amino group, amidino group, hydrazino group, hydrazono group, carboxyl group or its carboxylate, sulfonic acid group or its sulfonate, phosphoric acid group or its phosphate, C1-C 40 alkyl group, C2-C 40 alkenyl group, C2-C 40 alkynyl group, C1-C 40 alkoxy group, C3-C 40 cycloalkyl group, C3-C 40 cycloalkenyl group, C6-C 60 aryl group, C6-C 60 aryloxy group, C6-C 60 arylthioether group, and C2-C 60 heteroaryl group, or being substituted or unsubstituted by a substituent formed by linking two or more of the above-exemplified substituents.

[0093] In one example, the term substitution includes a combination of two to four of the listed groups.

[0094] In another example, the term substitution includes a combination of two to three groups. In yet another example, the term substitution includes a combination of two groups. Preferred combinations of substituents are combinations containing up to fifty atoms that are not hydrogen or deuterium, or combinations including up to forty atoms that are not hydrogen or deuterium, or combinations including up to thirty atoms that are not hydrogen or deuterium. In many cases, the preferred combination of substituents will include up to twenty atoms that are not hydrogen or deuterium.

[0095] According to an embodiment of the present invention, the metal complex is selected from the group consisting of:

[0096]

[0097]

[0098]

[0099]

[0100]

[0101]

[0102]

[0103]

[0104]

[0105]

[0106]

[0107] Some or all of the hydrogen atoms in the above structure may be replaced by deuterium atoms.

[0108] In a second aspect, the present invention provides an organic electroluminescent device, which includes an anode, a cathode, and at least one organic layer disposed between the anode and the cathode, and the organic layer contains a metal complex of formula (I).

[0109] The organic layer of the present invention may be an emission layer, and the metal complex as described herein may be an emission dopant or a non-emission dopant.

[0110] Furthermore, the organic layer may further contain a host material and a dopant, wherein the dopant contains a metal complex of formula (I).

[0111] The organic electroluminescent device of the present invention may further include an emission region, and the emission region contains a compound as disclosed in the above compound portion of the present disclosure.

[0112] Further, the host material is selected from the group consisting of triphenylene, carbazole, indolocarbazole, dibenzothiophene, dibenzofuran, fluorene, dibenzoselenophene, 5,9-dioxa-13b-boranaphtho[3,2,1-de]anthracene, aza-triphenylene, aza-carbazole, aza-indolocarbazole, aza-dibenzothiophene, aza-dibenzofuran, aza-dibenzoselenophene, and aza-(5,9-diaza-13b-boranaphtho[3,2,1-de]anthracene) or a combination derived from these systems.

[0113] Preferably, the host material is selected from the group consisting of the following structures:

[0114]

[0115]

[0116] Materials described herein as suitable for use in specific layers in an organic light emitting device can be used in combination with a variety of other materials present in the device. For example, the emissive dopants disclosed herein can be used in combination with a wide variety of hosts, transport layers, blocking layers, injection layers, electrodes, and other layers that may be present. The materials described or mentioned below are non-limiting examples of materials that can be used in combination with the compounds disclosed herein, and those skilled in the art can readily consult the literature to identify other materials that can be used in combination.

[0117] In some embodiments, the mass ratio of the host material to the doping material is from 99:1 to 1:99.

[0118] Preferably, the mass ratio of the host material to the doping material is from 98:2 to 50:50.

[0119] Further, the mass ratio of the host material to the doping material is from 98:2 to 90:10.

[0120] In a third aspect, the present invention provides a consumer product comprising the organic electroluminescent device described in the second aspect.

[0121] The consumer product of the present invention can be one of the following products: flat panel display, computer monitor, medical monitor, television, billboard, lamp for internal or external lighting and / or signaling, head-up display, fully transparent or partially transparent display, flexible display, laser printer, telephone, cellular phone, tablet computer, phablet, personal digital assistant (PDA), wearable device, laptop computer, digital camera, video camera, viewfinder, microdisplay with a diagonal of less than 2 inches, 3-D display, virtual reality or augmented reality display, vehicle, video wall comprising a plurality of tiled together displays, theater or stadium screen, light therapy device, and sign.

[0122] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0123] (1) When the metal complex of the present invention is used in an OLED, especially in the blue light emission region, it exhibits enhanced phosphorescence quantum yield, good luminescence stability, high luminescence efficiency, and is suitable as an emissive dopant in OLED applications. The metal complex of the present invention can obtain an organic electroluminescent device with blue phosphorescent electroluminescence and improved luminescence efficiency, and the luminescent device has good thermal stability. The consumer product of the organic light emitting device of the present invention can obtain an electronic device with blue phosphorescent electroluminescence and improved luminescence efficiency by containing the organic electroluminescent device of the present invention;

[0124] (2) The metal complex of the present invention regulates its photophysical properties by adjusting the structure of the ligands around the metal center and controlling the structure of the substituents on the ligands, and has the advantages of narrow emission spectrum, high stability and high efficiency, and has broad application prospects in many fields such as OLED displays and lighting lamps. Description of the Drawings

[0125] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0126] Figure 1 Show a schematic diagram of an organic electroluminescent device 100. The device 100 may include a substrate 101, an anode 102, a hole injection layer 103, a hole transport layer 104, an electron blocking layer 105, a light emitting layer 106, a hole blocking layer 107, an electron transport layer 108, an electron injection layer 109, a cathode 110, and a capping layer (CPL) 111. The device 100 can be fabricated by sequentially depositing the described layers.

[0127] Figure 2 Show a schematic diagram of an organic electroluminescent device 200 with two light emitting layers. The device includes a substrate 201, an anode 202, a hole injection layer 203, a hole transport layer 204, a first light emitting layer 205, an electron transport layer 206, a charge generation layer 207, a hole injection layer 208, a hole transport layer 209, a second light emitting layer 210, an electron transport layer 211, an electron injection layer 212, and a cathode 213. The emission peak shapes of the first light emitting layer and the second light emitting layer can be overlapping or cross-overlapping or non-overlapping. Detailed Description of the Embodiments

[0128] To make the objectives, technical solutions and advantages of the present invention clearer, the following will describe the technical solutions of the present invention in detail. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

[0129] "EQE" in the present invention refers to the external quantum efficiency of an element, that is, the ratio of the number of photons emitted by the element to the number of electrons injected into the element.

[0130] Figure 1 and Figure 2The simple layer structure described herein is provided as a non-limiting example, and it should be understood that embodiments of the present invention can be used in combination with a variety of other structures. The names given to the various layers herein are not intended to be strictly limiting. For example, in device 200, the hole transport layer 204 transports holes and injects holes into the light-emitting layer 205, and can be described as a hole transport layer or an electron blocking layer. In one embodiment, an OLED can be described as having an organic layer disposed between a cathode and an anode. This organic layer can include a single layer or can further include multiple layers of different organic materials as described, for example, Figure 1 and Figure 2 multiple layers of different organic materials.

[0131] Structures and materials not specifically described can also be used, such as PLEDs containing polymer materials. As another example, an OLED having a single organic layer or multiple stacks can be used. The OLED structure can deviate from Figure 1 and Figure 2 the simple layer structure described therein. For example, the substrate can include angled reflective surfaces to improve light coupling.

[0132] In any of the above-mentioned compounds used in each layer of the above OLED device, the hydrogen atoms can be partially or fully deuterated. Thus, any specifically listed substituents, such as (but not limited to) methyl, phenyl, pyridyl, etc., can be in their non-deuterated, partially deuterated, and fully deuterated forms. Similarly, substituent classes (such as (but not limited to) alkyl, aryl, cycloalkyl, heteroaryl, etc.) can also be in their non-deuterated, partially deuterated, and fully deuterated forms.

[0133] The materials and structures described herein can be applied to devices other than OLEDs. For example, other optoelectronic devices such as organic solar cells and organic photodetectors can use the materials and structures.

[0134] Furthermore, organic devices such as organic transistors can use the materials and structures.

[0135] In the following embodiments of the present invention, unless otherwise specified, conventional preparation methods are used. The raw materials used can be obtained from public commercial sources unless otherwise specified, and the percentages are mass percentages unless otherwise specified.

[0136] To more clearly illustrate the present invention, the technical solutions of the present invention are described below in conjunction with some specific embodiments:

[0137] In the embodiments of the present invention, the performance detection conditions of the prepared electroluminescent device are as follows:

[0138] Chromaticity coordinates: Measured using a spectral scanner PhotoResearch PR-715;

[0139] Current - voltage: Measured using a digital source meter Keithley 2420;

[0140] Power efficiency: Measured using NEWPORT 1931 - C;

[0141] Luminance: Measured using a luminance meter Minolta Cs - 1000A.

[0142] Example 1

[0143] A method for preparing the metal complex P5, which comprises the following steps:

[0144] The first step: Preparation of compound Int - 1

[0145]

[0146] Under nitrogen protection, 25.0 mmol of compound S1 was dissolved in 110 mL of toluene, and then 75.0 mmol of anhydrous potassium carbonate, 5.0 mmol of copper(I) iodide, 30.0 mmol of compound S2 and 15.0 mmol of N,N’ - dimethylethylenediamine were added. The temperature was raised to reflux and stirred for 15 hours. After cooling to room temperature, filtration was carried out, and the filtrate was concentrated to dryness and purified by silica gel column chromatography to obtain intermediate Int - 1, a yellow solid, with a yield of 86%.

[0147] The second step: Preparation of compound Int - 2

[0148]

[0149] Under nitrogen protection, 22.0 mmol of compound Int - 1 and 20.0 mmol of compound S3 were dissolved in 50 mL of DMF, and then 40.0 mmol of anhydrous potassium carbonate was added. The temperature was raised to 125 °C and stirred for 15 hours. After cooling to room temperature, the reaction solution was poured into 200 mL of water, filtered, and the filter cake was washed with water and purified by silica gel column chromatography to obtain intermediate Int - 2, a yellow solid, with a yield of 90%.

[0150] The third step: Preparation of compound Int - 3

[0151]

[0152] Under nitrogen protection, 20.0 mmol of compound Int-2 was dissolved in 80 mL of dichloromethane. The temperature was lowered to 0 °C, and 30.0 mmol of boron tribromide was added dropwise. The mixture was stirred at room temperature for 2 hours. 100 mL of saturated ammonium chloride aqueous solution was added dropwise, and the organic phase was separated. The aqueous phase was extracted with dichloromethane, and the organic phases were combined, dried, filtered, and the filtrate was concentrated and dried under reduced pressure. It was separated and purified by silica gel column chromatography to obtain intermediate Int-3, a yellow solid, with a yield of 92%.

[0153] Step 4: Preparation of compound Int-4

[0154]

[0155] Under nitrogen protection, 20.0 mmol of compound Int-3 was dissolved in 60 mL of DMF, and then 30.0 mmol of 5-tert-butyl-2-bromofluorobenzene and 60.0 mmol of anhydrous cesium carbonate were added. The temperature was raised to 120 °C and the mixture was stirred for 12 hours. After cooling to room temperature, the reaction solution was poured into 200 mL of water, filtered, and the filter cake was washed with water and dried. It was separated and purified by silica gel column chromatography to obtain yellow solid Int-4, with a yield of 87%.

[0156] Step 5: Preparation of compound Int-5

[0157]

[0158] Under nitrogen protection, 10.0 mmol of the compound Int-4 prepared in the previous step was mixed with 80 mL of dry anisole, and the temperature was lowered to -78 °C. 12.0 mmol of 2.5 M n-butyllithium in n-hexane solution was slowly added dropwise, and the mixture was stirred for 30 minutes. 12.0 mmol of boron tribromide was added dropwise, and the mixture was stirred for 30 minutes. Then it was stirred at room temperature for 30 minutes, and 0.1 mol of diisopropylethylamine was added dropwise. The temperature was raised to above 150 °C and the mixture was stirred for 15 hours. After cooling to room temperature, it was concentrated and dried under reduced pressure. It was separated and purified by silica gel column chromatography to obtain compound Int-4, a yellow solid, with a yield of 52%.

[0159] Step 6: Preparation of compound Int-6

[0160]

[0161] Under nitrogen protection, 10.0 mmol of compound Int-5 was dissolved in 50 mL of DMF, and 22.0 mmol of S4 [bis(3,5-di-tert-butylphenyl)iodonium trifluoromethanesulfonate] and 0.4 mmol of anhydrous copper acetate were added. The temperature was raised to reflux and the mixture was stirred for 2 hours. After cooling to room temperature, it was filtered, and the filtrate was poured into 150 mL of ice water, filtered, and the filter cake was washed with water and ethanol to obtain yellow solid Int-6, with a yield of 77%.

[0162] Step 7: Preparation of Compound P5

[0163]

[0164] Under nitrogen protection, 15.0 mmol of Compound Int-6 was dissolved in 200 mL of DMF. 15.0 mmol of Pt(COD)Cl2 and 45.0 mmol of anhydrous sodium acetate were added. The mixture was stirred and heated to reflux for 15 hours, then cooled to room temperature. The solvent was concentrated under reduced pressure until dry. Dichloromethane was added to dissolve the residue, and the organic phase was collected, washed with water, dried, filtered, and the filtrate was concentrated under reduced pressure until dry. The residue was separated and purified by silica gel column chromatography to obtain Compound P5 as a brown solid with a yield of 36%. HRMS(ESI): 1018.3765 [M+H]. 1 HNMR(δ, CDCl3): 8.04 - 8.02 (1H, d); 7.89 - 7.87 (1H, d); 7.84 - 7.82 (1H, d); 7.59 (1H, s); 7.51 - 7.48 (1H, m); 7.34 - 7.30 (1H, m); 7.27 - 7.20 (5H, m); 7.17 - 7.15 (1H, d); 7.07 (1H, s); 7.03 - 7.00 (1H, m); 6.93 (1H, s); 6.90 - 6.88 (1H, dd); 6.84 - 6.82 (1H, d); 6.78 - 6.76 (1H, d); 2.15 (3H, s); 2.02 (3H, s); 1.40 (18H, s); 1.26 (9H, s).

[0165] Example 2

[0166] A method for preparing metal complex P35, which comprises the following steps:

[0167] Step 1: Preparation of Compound Int-7

[0168]

[0169] Under nitrogen protection, 25.0 mmol of 2-methoxy-7-bromocarbazole (Compound S5), 2.5 mmol of copper(I) iodide, 50.0 mmol of lithium tert-butoxide and 80 mL of toluene were mixed. Then 27.5 mmol of 2-bromo-5-tert-butylpyridine (Compound S6) and 5.0 mmol of 1-methylimidazole were added. The mixture was heated to reflux and stirred for 48 hours. After cooling to room temperature, 50 mL of water was added and stirred to dissolve. The organic phase was separated, and the aqueous phase was extracted with ethyl acetate. The combined organic phases were washed with saturated brine, dried, filtered, and the filtrate was concentrated until dry. The residue was separated and purified by silica gel column chromatography to obtain Compound Int-7 as a white solid with a yield of 95%.

[0170] Step 2: Preparation of Compound Int-8

[0171]

[0172] Under nitrogen protection, 20.0 mmol of Compound Int-7 was dissolved in 80 mL of dry THF. 24.0 mmol of potassium tert-butoxide was added, and the temperature was lowered to -78 °C. A solution of 22.0 mmol of 2.5 M n-butyllithium in n-hexane was added dropwise, and the mixture was stirred for 10 minutes. A THF solution of 2-bromo-4-tert-butylbenzyl bromide was added dropwise, and the mixture was stirred for 30 minutes. The temperature was raised to room temperature and stirred for 2 hours. 100 mL of saturated ammonium chloride aqueous solution was added dropwise, and the organic phase was separated. The aqueous phase was extracted with ethyl acetate. The organic phases were combined, dried, filtered, and the filtrate was concentrated and dried under reduced pressure. It was separated and purified by silica gel column chromatography to obtain Compound Int-8, a yellow solid, yield: 90%.

[0173] Step 3: Preparation of Compound Int-9

[0174]

[0175] Under nitrogen protection, 20.0 mmol of Compound Int-8 was dissolved in 50 mL of dry DMSO. The temperature was lowered to 0 °C, 60.0 mmol of potassium hydroxide was added, and the mixture was stirred for 30 minutes. 60.0 mmol of methyl iodide was added, and the mixture was stirred for 2 hours. 10.0 mmol of methyl iodide was added additionally, and the temperature was raised to room temperature and stirred for 12 hours. The reaction solution was poured into 150 mL of saturated ammonium chloride aqueous solution, filtered, and the filter cake was washed with water. It was separated and purified by silica gel column chromatography to obtain Compound Int-9, a yellow solid, yield: 94%.

[0176] Step 4: Preparation of Compound Int-10

[0177]

[0178] Under nitrogen protection, 10.0 mmol of Compound Int-9 prepared in the previous step, 12.0 mmol of potassium tert-butoxide and 100 mL of dry tert-butylbenzene were mixed, and the temperature was lowered to -78 °C. A solution of 14.0 mmol of 2.5 M n-butyllithium in n-hexane was added dropwise slowly, and the mixture was stirred for 1 hour. 15.0 mmol of boron tribromide was added dropwise slowly, and the mixture was stirred for 1 hour. The temperature was raised to room temperature. Then 0.1 mol of diisopropylethylamine was added dropwise, and the temperature was raised to 155 °C and stirred for 48 hours. It was cooled to room temperature. The reaction solution was poured into 200 mL of ethanol, filtered, and the filter cake was washed with ethanol. The solid was separated and purified by silica gel column chromatography to obtain Compound Int-10, a yellow solid, yield 52%.

[0179] Step 5: Preparation of Compound Int-11

[0180]

[0181] Under nitrogen protection, 20.0 mmol of compound Int-10 was dissolved in 80 mL of dry dichloromethane, the temperature was lowered to 0 °C, 30.0 mmol of boron tribromide was added dropwise, and the mixture was stirred at room temperature for 2 hours. 100 mL of saturated ammonium chloride aqueous solution was added dropwise, the organic phase was separated, the aqueous phase was extracted with dichloromethane, the organic phases were combined, dried, filtered, the filtrate was concentrated and dried under reduced pressure, and purified by silica gel column chromatography to obtain compound Int-11, a yellow solid, yield: 95%.

[0182] Step 6: Preparation of compound Int-12

[0183]

[0184] Under nitrogen protection, 20.0 mmol of compound Int-11, 24.0 mmol of compound S7, 2.0 mmol of cuprous iodide, 40.0 mmol of anhydrous potassium phosphate, 4.0 mmol of 2-pyridinecarboxylic acid and 50 mL of DMSO were mixed, the temperature was raised to 110 °C, and the mixture was stirred and reacted for 48 hours. The temperature was lowered to room temperature, 150 mL of saturated ammonium chloride aqueous solution of 5% acetic acid was added, extracted with ethyl acetate, the organic phases were combined and washed with saturated brine, dried, filtered, the filtrate was concentrated and dried under reduced pressure, and purified by silica gel column chromatography to obtain compound Int-12, a yellow solid, yield: 86%.

[0185] Step 7: Preparation of compound P35

[0186]

[0187] Under nitrogen protection, 15.0 mmol of compound Int-12 was dissolved in 100 mL of acetic acid, 16.5 mmol of K2PtCl4 and 45.5 mmol of anhydrous sodium acetate were added, and the mixture was stirred and heated to reflux for 48 hours. The temperature was lowered to room temperature, concentrated to dryness under reduced pressure, extracted with dichloromethane, filtered, the filtrate was concentrated to dryness under reduced pressure, and purified by silica gel column chromatography to obtain compound P35, a brown solid, yield: 57%. HRMS(ESI): 910.3192[M+H]. 1HNMR (δ, CDCl3): 8.75 (1H, s); 8.46 (1H, s); 8.25 (1H, s); 8.07 (1H, s); 7.89 - 7.87 (1H, d); 7.78 - 7.76 (1H, d); 7.68 - 7.66 (1H, d); 7.49 - 7.45 (3H, m); 7.27 - 7.22 (3H, m); 7.16 - 7.10 (3H, m); 6.96 - 6.94 (1H, d); 6.88 - 6.86 (1H, d); 6.65 (1H, s); 1.68 (3H, s); 1.64 (3H, s); 1.36 (9H, s); 1.11 (9H, s).

[0188] Example 3

[0189] Preparation of metal complex P100, which comprises the following steps:

[0190] First step: Preparation of compound Int-13

[0191]

[0192] Under nitrogen protection, 25.0 mmol of 85% potassium hydroxide was dissolved in 50 mL of DMSO, cooled to 0 °C, and 20.0 mmol of compound S8 was added. The mixture was stirred for 1 hour. Then 24.0 mmol of 1-benzyl-2-chloro-benzimidazole (compound S9) was added, and the temperature was raised to 45 °C and stirred for 48 hours. The reaction solution was poured into 150 mL of ice water, filtered, the filter cake was washed with water, dried and purified by silica gel column chromatography to obtain compound Int-12, a yellow solid, yield: 94%.

[0193] Second step: Preparation of compound Int-14

[0194]

[0195] Under nitrogen protection, 20.0 mmol of compound Int-13 was dissolved in 80 mL of dry dichloromethane and cooled to 0 °C. 60.0 mmol of boron tribromide was added dropwise, and the mixture was stirred at room temperature for 2 hours. 100 mL of saturated ammonium chloride aqueous solution was added dropwise, the organic phase was separated, the aqueous phase was extracted with dichloromethane, the organic phases were combined, dried, filtered, and the filtrate was concentrated and dried under reduced pressure and purified by silica gel column chromatography to obtain compound Int-14, a yellow solid, yield: 92%.

[0196] Third step: Preparation of compound Int-15

[0197]

[0198] Under nitrogen protection, 20.0 mmol of compound Int-14, 24.0 mmol of 3-tert-butylbromobenzene (compound S10), 2.0 mmol of cuprous iodide, 40.0 mmol of anhydrous potassium carbonate, 4.0 mmol of 2-pyridinecarboxylic acid and 50 mL of DMSO were mixed, heated to 110 °C, and stirred for reaction for 48 hours. After cooling to room temperature, 150 mL of saturated ammonium chloride aqueous solution of 5% acetic acid was added, extracted with ethyl acetate, the organic phases were combined, washed with saturated brine, dried, filtered, the filtrate was concentrated and dried under reduced pressure, and separated and purified by silica gel column to obtain compound Int-15, a yellow solid, yield: 83%.

[0199] Step 4: Preparation of compound Int-16

[0200]

[0201] 20.0 mmol of compound Int-15 was dissolved in 80 mL of ethanol, 10 mL of THF and 10 mL of concentrated hydrochloric acid, then 0.5 g of 10% Pd / C was added, hydrogen was introduced at atmospheric pressure, and the mixture was stirred for reaction for 12 hours. Filtered, the filter cake was washed with THF, the filtrate was concentrated and dried under reduced pressure, and separated and purified by silica gel column to obtain compound Int-16, a yellow solid, yield: 90%.

[0202] Step 5: Preparation of compound Int-17

[0203]

[0204] Under nitrogen protection, 10.0 mmol of compound Int-16, 60.0 mmol of diisopropylethylamine and 100 mL of dry anisole were mixed, 22.0 mmol of boron tribromide was slowly added dropwise, stirred for reaction for 1 hour, heated to above 150 °C and stirred for reaction for 48 hours, and cooled to room temperature. The reaction solution was poured into 200 mL of ethanol, filtered, the filter cake was washed with ethanol, and the solid was separated and purified by silica gel column to obtain compound Int-17, a yellow solid, yield 73%.

[0205] Step 6: Preparation of compound Int-18

[0206]

[0207] Referring to the synthesis method of Step 3, compound Int-14 in Step 3 was replaced with compound Int-17, and compound S10 was replaced with compound S11 to prepare compound Int-18, a yellow solid, yield: 89%.

[0208] Step 7: Preparation of compound Int-19

[0209]

[0210] Referring to the synthesis method of the sixth step of Example 1, only replace the compound Int-5 in the sixth step of Example 1 with the compound Int-18 to prepare the compound Int-19, yellow solid, yield: 68%.

[0211] Eighth step: Preparation of compound P100

[0212]

[0213] Referring to the synthesis method of the seventh step of Example 1, only replace the compound Int-6 in the seventh step of Example 1 with the compound Int-19 to prepare the compound P100, yield: 46%, HRMS(ESI): 1029.3563[M+H]. 1 HNMR(δ, DMSO-d6): 8.37~8.35(1H, d); 8.06~8.03(1H, d); 7.64~7.62(1H, d); 7.55~7.51(2H, m); 7.22~7.16(4H, m); 7.14~7.07(4H, m); 7.05(1H, s); 7.02(1H, s); 6.98(1H, s); 6.96~6.92(2H, m); 6.90~6.88(1H, dd); 6.86~6.84(1H, d); 6.82~6.80(1H, dd); 1.39(18H, s); 1.26(9H, s).

[0214] Example 4

[0215] Preparation of metal complex P207, which comprises the following steps:

[0216] First step: Preparation of compound Int-20

[0217]

[0218] Referring to the synthesis method of the first step of Example 3, replace the compound S8 in the first step of Example 3 with the compound S5, and replace the compound S9 with the compound S12 to prepare the compound Int-20, yellow solid, yield: 93%.

[0219] Second step: Preparation of compound Int-21

[0220]

[0221] Under nitrogen protection, 22.0 mmol of compound Int-20, 20.0 mmol of 3,6-di-tert-butylcarbazole, 30.0 mmol of sodium tert-butoxide and 80 mL of xylene were mixed, and then 0.1 mmol of Pd2(dba)3 and 0.2 mmol of 10% tri-tert-butylphosphine toluene solution were added. The temperature was raised to 110 °C and the mixture was stirred for reaction for 15 hours. After cooling to room temperature, 50 mL of saturated ammonium chloride aqueous solution was added, and the organic phase was separated. The aqueous phase was extracted with ethyl acetate, and the combined organic phases were washed with water, dried, filtered, and the filtrate was concentrated and dried under reduced pressure, and then separated and purified by silica gel column chromatography to obtain compound Int-21, a white solid, yield: 85%.

[0222] Step 3: Preparation of compound Int-22

[0223]

[0224] Referring to the synthesis method in the fourth step of Example 3, only replacing compound Int-15 in the fourth step of Example 3 with compound Int-21, compound Int-22 was prepared, a yellow solid, yield: 95%.

[0225] Step 4: Preparation of compound Int-23

[0226]

[0227] Referring to the synthesis method in the fifth step of Example 3, only replacing compound Int-16 in the fifth step of Example 3 with compound Int-22, compound Int-23 was prepared, a yellow solid, yield: 55%.

[0228] Step 5: Preparation of compound Int-24

[0229]

[0230] Referring to the synthesis method in the fifth step of Example 2, only replacing compound Int-10 in the fifth step of Example 2 with compound Int-23, compound Int-24 was prepared, a yellow solid, yield: 91%.

[0231] Step 6: Preparation of compound Int-25

[0232]

[0233] Under nitrogen protection, 20.0 mmol of compound Int-24, 24.0 mmol of compound S11, 2.0 mmol of copper(I) iodide, 40.0 mmol of anhydrous potassium carbonate, 4.0 mmol of 2-pyridinecarboxylic acid and 50 mL of DMSO were mixed, heated to 110 °C, and stirred for reaction for 48 hours. After cooling to room temperature, the reaction solution was poured into 150 mL of saturated ammonium chloride aqueous solution of 5% acetic acid, filtered, the filter cake was washed with water, separated and purified by silica gel column to obtain compound Int-25, a yellow solid, yield: 80%.

[0234] Step 7: Preparation of compound Int-26

[0235]

[0236] Referring to the synthesis method of Step 6 in Example 1, only replacing compound Int-5 in Step 6 of Example 1 with compound Int-25, compound Int-26 was prepared, a yellow solid, yield: 52%.

[0237] Step 8: Preparation of compound P207

[0238]

[0239] Under nitrogen protection, 15.0 mmol of compound Int-26 was dissolved in 100 mL of DMF and 100 mL of ethylene glycol monomethyl ether, 15.0 mmol of Pt(COD)Cl2 and 45.0 mmol of anhydrous potassium acetate were added, and the mixture was stirred and heated to reflux for reaction for 48 hours. After cooling to room temperature, it was concentrated to dryness under reduced pressure, dissolved in dichloromethane, the organic phase was collected, washed with water, dried, filtered, the filtrate was concentrated to dryness under reduced pressure, and separated and purified by silica gel column to obtain compound P207, a yellow solid, yield: 44%. HRMS(ESI): 1160.4412[M+H]. 1 HNMR(δ, CDCl3): 8.65~8.64(1H, d); 8.56~8.55(1H, d); 8.52~8.50(1H, d); 7.92(1H, s); 7.60~7.58(2H, m); 7.52~7.48(2H, m); 7.41~7.38(2H, m); 7.34~7.30(1H, m); 7.27~7.23(3H, m); 7.21~7.19(1H, m); 7.14~7.10(2H, m); 7.08~7.05(2H, m); 7.03~7.00(1H, m); 6.97~6.95(1H, d); 1.40(18H, s); 1.39(9H, s); 1.33(9H, s).

[0240] Examples 5 to 204

[0241] Prepare the following compounds by a synthetic method similar to that of the above-mentioned embodiments:

[0242]

[0243]

[0244]

[0245]

[0246]

[0247]

[0248]

[0249]

[0250]

[0251]

[0252]

[0253]

[0254]

[0255]

[0256]

[0257]

[0258]

[0259]

[0260] Preparation of Organic Electroluminescent Devices

[0261] Ultrasonically treat the glass substrate with the patterned ITO electrode in a cleaning agent for 30 minutes, rinse it in deionized water, ultrasonically treat it in an acetone / ethanol mixed solvent for 30 minutes, and bake it in a clean environment until completely dry. Irradiate it with an ultraviolet light cleaning machine for 10 minutes, and bombard the surface with a low-energy cation beam.

[0262] Place the above-treated ITO glass substrate in a vacuum chamber, evacuate it to less than 1×10 -5 Pa, and deposit metallic silver as the anode on the above ITO film. The deposited film thickness is Continuously deposit the compound HATCN by evaporation as the hole injection layer, with the evaporation film thickness being On the above hole injection layer film, continuously deposit the compound HTM by evaporation as the hole transport layer, with the evaporation film thickness being

[0263] On the above hole transport layer, deposit the compound BPrime by evaporation as the electron blocking layer, with the evaporation film thickness being

[0264] On the above electron blocking layer, deposit the metal complex of the present invention and PH032 by evaporation as the organic light-emitting layer of the device. Among them, PH032 is the host material and the metal complex of the present invention is the doping material, with the doping concentration being 5%, and the evaporation film thickness being

[0265] On the above organic light-emitting layer, continue to deposit a layer of the compound DPO by evaporation as the hole blocking layer of the device, with the evaporation film thickness being

[0266] On the above hole blocking layer, continue to deposit a layer of LiQ and the compound ET325 by evaporation as the electron transport layer of the device. Among them, LiQ is 50% of the mass of ET325, and the evaporation film thickness is

[0267] On the above electron transport layer, continue to deposit a layer of LiF by evaporation as the electron injection layer of the device, with the evaporation film thickness being

[0268] On the above electron injection layer, deposit metal magnesium and silver by evaporation as the cathode layer of the device. Among them, the mass ratio of magnesium to silver is 1:10, and the evaporation film thickness is

[0269] Finally, on the cathode layer, deposit the compound HTM by evaporation as the capping layer, with the evaporation film thickness being Fabricate the organic electroluminescent element of the present invention, as shown in the attached Figure 1 device 100.

[0270] Comparative Example 1

[0271] Use the compound shown by the compound BD012 to replace the metal complex of the above organic electroluminescent device, and the other steps are the same as above to fabricate Comparative Element 1. The structural formulas of the aforementioned HATCN, HTM, BPrime, PH032, BD012, DPO, and ET325 are as follows:

[0272]

[0273] For the above-prepared organic electroluminescent device, a digital source meter and a luminance meter were used to measure the driving voltage, current efficiency, and roll-off ratio of the light-emitting device. Specifically, the voltage was increased at a rate of 0.1 V per second, and the voltage when the current density of the organic electroluminescent device reached 10 mA / cm 2 was measured as the driving voltage, and the luminance at this time was also measured; the ratio of luminance to current density was the current efficiency; the roll-off ratio was calculated according to the following process:

[0274] Roll-off ratio = [1 - (efficiency at a current density of 50 mA / cm 2 / maximum efficiency of the device)] × 100%;

[0275] Some of the results are summarized in Table 1, *The data is normalized compared to Comparative Element 1 for easy comparison.

[0276] Table 1

[0277]

[0278]

[0279]

[0280]

[0281]

[0282] As can be seen from Table 1, compared with Comparative Element 1, the organic electroluminescent device prepared with the metal complex of the present invention has a lower driving voltage, a higher emission efficiency, and a relatively gentle roll-off curve.

[0283] Compared with the metal complex BD012 of Comparative Element 1, in the metal-to-ligand charge transfer (MLCT) process of the metal complex of the present invention, the boron-carbon-nitrogen ligand is used to replace the boron-nitrogen-nitrogen ligand, and the conjugation effect of boron-carbon-nitrogen is fully utilized to achieve the TADF effect, enhance the charge rate in the metal polarization direction of Pt^C, and at the same time reduce the relaxation degree of the excited state. Therefore, the efficiency of the metal complex of the present invention is significantly improved compared with BD012, and the efficiency roll-off phenomenon is significantly improved.

[0284] As described above, only the representative examples of the specific embodiments of the present invention are given, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, and all should be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claimed rights.

Claims

1. A metal complex, characterized in that, The metal complex contains the structure shown in formula (I): Wherein, ring A, ring B, ring C, and ring D are each a 5-membered carbon ring, a 5-membered heterocyclic ring, a 6-membered carbon ring, or a 6-membered heterocyclic ring; Metal M represents a metal element with an atomic weight greater than 40; X 1 ~X 7 Each independently selected from C, CH or N; R 1 、R 2 、R 5 、R 6 each represents mono-substituted, multi-substituted up to fully saturated substitution, or unsubstituted; R 3 and R 4 each represents mono-substitution or di-substitution; L 1 Selected from a single bond, O, S, S═O, SO2, Se, NR 7 , PR 7 , R 7 P═O, CR 7 R 8 , C═O, SiR 7 R 8 , GeR 7 R 8 or BR 7 ; L 2 selected from O, S, S=O, SO2, Se, NR 7 , PR 7 , R 7 P=O, CR 7 R 8 , C=O, SiR 7 R 8 , GeR 7 R 8 or BR 7 ; R 1 to R 8 each independently selected from hydrogen or the group consisting of: hydrogen, deuterium, a halogen atom, a nitrile group, an acyl group, a carboxyl group, an ether group, an ester group, an isonitrile group, a sulfur group, a selenoalkyl group, a sulfinyl group, a sulfonyl group, a phosphino group, a C1-C 40 linear alkyl group, a C1-C 40 linear heteroalkyl group, a C3-C 40 branched or cyclic alkyl group, a C1-C 40 alkoxy group, a C6-C 60 arylalkyl group, a C6-C 60 aryloxy group, a C6-C 60 arylamino group, a C3-C 40 silyl group, a C2-C 40 alkenyl group, a C4-C 40 cycloalkenyl group, a C2-C 40 heteroalkenyl group, a C2-C 40 alkynyl group, a C6-C 60 aryl group, a C2-C 60 heteroaryl group, and any two or more adjacent R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 and R 8 may optionally be joined or fused to form a substituted or unsubstituted ring; Optionally, the group(s) of R 1 ~R 8 is / are substituted with one or more substituents selected from deuterium, a halogen atom, a nitrile group, a linear alkyl group having 1 to 6 carbon atoms, and a branched alkyl group having 3 to 6 carbon atoms.

2. The metal complex according to claim 1, wherein The metal complex is selected from the group consisting of: wherein, each Y independently represents O, S or NR 9 ; R 1 ~R 6 、L 1 、L 2 are defined in the same manner as those in formula (I); R 9 selected from the group consisting of: hydrogen, C1-C 40 linear alkyl, C1-C 40 linear heteroalkyl, C3-C 40 branched or cyclic alkyl, C6-C 60 arylalkyl, C3-C 40 silyl, C2-C 40 alkenyl, C4-C 40 cycloalkenyl, C2-C 40 heteroalkenyl, C2-C 40 alkynyl, C6-C 60 aryl, C2-C 60 heteroaryl; Ring C is selected from an aromatic ring of C6-C 60 or a heteroaromatic ring of C2-C 60 ; M is selected from Ir, Pt, Pd, Ru, Rh, Os, Au, Cu, Ni, Co, Ga, or Ge.

3. The metal complex according to claim 1 or 2, wherein The M is selected from Pt or Pd; R 9 Selected from straight-chain alkyls of C1 to C 40 , straight-chain heteroalkyls of C1 to C 40 , branched or cyclic alkyls of C3 to C 40 , aryls of C6 to C 60 , heteroaryls of C2 to C 60 and combinations thereof.

4. The metal complex according to any one of claims 1 to 3, characterized in that, The M is Pt; R 1 、R 2 、R 3 、R 4 、R 5 、R 6 Each independently selects from the group consisting of a hydrogen atom, a deuterium atom, fluorine, a cyano group, an isocyano group, R A1 to R A30 、R B1 to R B195 、R C1 to R C80 ; R 7 、R 8 、R 9 Each independently selects from the group consisting of R A1 to R A30 、R B1 to R B195 、R C1 to R C80 ; Among them, R A1 ~R A30 The structural formulas are shown as follows: R B1 ~R B195 The structure shown is as follows: R C1 ~R C80 The structure shown is as follows: Wherein each hydrogen atom in each substituent can be partially or completely replaced by a deuterium atom.

5. The metal complex according to any one of claims 1 to 4, characterized in that, The said L 1 is selected from a single bond, O, S, NR 7 , CR 7 R 8 or BR 7 ; L 2 selected from O, S, NR 7 , CR 7 R 8 or BR 7 ; R 7 and R 8 each independently selected from the group consisting of R A1 to R A30 and R B1 to R B195 and R C1 to R C80 ; Ring C is selected from the group consisting of the following groups: Among them, two adjacent "*" represent the bonding positions with L 2 and B; G is selected from O, S, Se, NR 10 , SiR 10 R 11 or GeR 10 R 11 ; R 10 and R 11 each independently selected from the group consisting of R A1 to R A30 , R B1 to R B195 , R C1 to R C80 .

6. The metal complex according to any one of claims 1 to 5, characterized in that, The described metal complex is selected from the group consisting of: Some or all of the hydrogen atoms in the above structure can be replaced by deuterium atoms.

7. An organic electroluminescent device, the organic electroluminescent device includes an anode, a cathode, and at least one organic layer disposed between the anode and the cathode, and the organic layer includes the metal complex according to any one of claims 1 to 6.

8. The organic electroluminescent device according to claim 7, wherein, The organic layer further includes a host material and a doping material, the doping material includes the metal complex according to any one of claims 1 to 6; the host material is selected from the group consisting of triphenylene, carbazole, indolocarbazole, dibenzothiophene, dibenzofuran, fluorene, dibenzoselenophene, 5,9-dioxa-13b-boranaphtho[3,2,1-de]anthracene, aza-triphenylene, aza-carbazole, aza-indolocarbazole, aza-dibenzothiophene, aza-dibenzofuran, aza-dibenzoselenophene, and aza-(5,9-diaza-13b-boranaphtho[3,2,1-de]anthracene) or a combination derived from these systems.

9. The organic electroluminescent device according to claim 8, wherein The host material is selected from the group consisting of the following structures:

10. The organic electroluminescent device according to claim 8 or 9, characterized in that, The mass ratio of the host material to the doping material is 99:1 to 1:99.

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