Metal complex, preparation method therefor, use thereof, and preparation method for olefin copolymer

Abstract

The present invention relates to the technical fields of materials and chemical engineering. Disclosed are a metal complex, a preparation method therefor, the use thereof, and a preparation method for an olefin copolymer. The metal complex has a structure shown as formula (I), wherein R has a structure shown as formula (II). The metal complex has high activity when being used to catalyze olefin copolymerization; and raw materials for preparing the catalyst are cheap and low in toxicity, thus facilitating industrial application.

Description

Metal complex, preparation method and application thereof, and preparation method of olefin copolymer

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of Chinese patent application No. 202311228537.9, filed on September 22, 2023, entitled “Metal complex, preparation method and application thereof, and preparation method of olefin copolymer”, the contents of which are incorporated herein by reference. Technical Field

[0003] The present invention relates to the technical field of materials and chemical engineering, and in particular to a metal complex and a preparation method and application thereof, as well as a preparation method of an olefin copolymer. Background Art

[0004] Under high temperature and high pressure conditions, copolymers of ethylene and polar group-containing vinyl monomers (acrylates, vinyl acetate, etc.) with many branches, low crystallinity and low mechanical properties can be obtained through free radical polymerization. In addition, by using a suitable catalyst, the harsh reaction conditions can be reduced, while reducing polymer branches, improving its crystallinity and mechanical properties. The use of late transition metals to prepare coordination compounds as catalysts is a method that has attracted widespread attention. The activity of such catalysts is largely determined by the ligand structure. In addition, the metal Pd is rare and precious, which greatly increases the cost of catalyst preparation, making it difficult for Pd-based catalysts to be promoted to industrial applications.

[0005] The SHOP (Shell Higher Olefins Process) catalyst developed by Shell uses a PO-type ligand and divalent nickel ions to form a neutral complex catalyst. When used for the copolymerization of polar monomers, it can only catalyze monomers in which the polar group and double bond are far apart, resulting in a limited range of applications.

[0006] The bis-imine ligand palladium complex catalyst disclosed in USP 4698403 can produce ethylene / acrylate copolymers with rich branching structures. "Mechanistic Studies of Catalytic Olefin Dimerization Reactions Using Electrophilic η3-Allyl-Palladium(II) Complexes" (GM Direnzo et al., J Am Chem Soc, 1996, 118, 6225) and "Mechanistic Studies of the Palladium-Catalyzed Copolymerization of Ethylene and α-Olefins with Methyl Acrylate" (S. Mecking et al., J Am Chem Soc, 1998, 120, 888) disclose bis-imine cationic catalysts (primarily iron and cobalt ions) that can be used for the copolymerization of ethylene and methyl methacrylate with methylaluminoxane as a cocatalyst. Polymers with a high degree of branching can also be obtained, but the polar monomer is only present at the polymer ends, not in the main chain. These highly branched copolymers all have low crystallinity.

[0007] "Functionalised polyolefin synthesis using [P,O]Ni catalysts" (VC Gibson et al., Chem Commun, 2001, 1964), "Late-Metal Catalysts for Ethylene Homo- and Copolymerization" (SD Ittelet et al., Chem Rev, 2000, 100, 1169), and "Palladium catalyzed copolymerization of ethene with alkylacrylates: polar comonomer built into the linear polymer chain" (E. Drent et al., Chem Commun, 2002, 744) disclose palladium complex catalysts with phosphinesulfonic acid ligands. These catalysts can be used for the copolymerization of ethylene with various polar monomers. However, as previously mentioned, the palladium metal used in these catalysts is extremely expensive, making them difficult to commercialize.

[0008] CN102197040A uses diphenylphosphine-substituted phenol as the core ligand structure, preferably nickel as the central metal, to prepare a catalyst for synthesizing α-olefins / (meth)acrylates. The resulting copolymer has few molecular branches and a high molecular weight; however, even under optimal conditions, the catalyst's copolymerization activity remains low, and the primary ligand raw material is phenol, which is acutely toxic.

[0009] CN106632507A uses diphenylphosphine as a core ligand instead of indole, preferably with nickel as the central metal, to prepare a catalyst for the copolymerization of α-olefins with one or more polar monomers such as acrylates, methacrylates, acrylic acid, unsaturated carboxylates, acrylamides, olefinonitriles, enols, and olefin ethers. The binary copolymers exhibit minimal molecular branching and high molecular weight. However, the catalyst still suffers from low copolymerization activity, and similarly, the primary ligand synthesis raw material is indole, which is acutely toxic.

[0010] CN109320558A uses a naphthol skeleton as the core ligand structure and nickel as the central metal to prepare polar monomers for ethylene and acrylates. Copolymerization activity is improved. However, the technical drawbacks or shortcomings of this invention are that the copolymerization activity of the catalyst in the optimal embodiment still needs to be further improved. However, the catalyst is only suitable for homopolymerization or copolymerization of ethylene, limiting its application range. The primary ligand raw materials are highly toxic pyridine and naphthol, and toxicity issues remain unaddressed.

[0011] Despite the improved performance of current catalysts, their copolymerization activity remains significantly lower than that achieved using Ziegler-Natta catalysts, and even lower than homopolymerization. Furthermore, significant toxicity remains a concern during catalyst preparation. From an industrial application perspective, continued efforts should be made to develop and enhance the copolymerization activity of these catalysts.

[0012] Summary of the Invention

[0013] The purpose of the present invention is to overcome the problems of low activity of catalysts in the prior art when catalyzing olefin copolymerization, expensive raw materials for preparing the catalysts, and high toxicity. A metal complex, a preparation method and application thereof, and a preparation method of an olefin copolymer are provided. When the metal complex is used to catalyze olefin copolymerization, the activity is high, and the raw materials for preparing the catalysts are cheap and low in toxicity, which is more conducive to industrial application.

[0014] In order to achieve the above object, the first aspect of the present invention provides a metal complex having a structure shown in formula (I):

[0015] Wherein, R has the structure shown in formula (II),

[0016] wherein M is selected from at least one of metals of Groups IVB, VB, VIB, VIIB and VIII, X is oxygen or sulfur, and E1 is nitrogen or phosphorus;

[0017] R1 and R1' are each independently selected from hydrogen, a hydrocarbon group having 1 to 20 carbon atoms and optionally containing a heteroatom substituent; or, R1, R1' and the central carbon atom in formula (I) together form a 5-8 membered ring optionally containing a heteroatom substituent;

[0018] R3 and R4 are each independently selected from hydrogen, a chain hydrocarbon group having 1 to 20 carbon atoms and optionally containing a substituent, and a 5-8 membered ring with or without a substituent and containing or not containing a heteroatom;

[0019] R7 is selected from one of hydrogen, halogen, and a hydrocarbon group having 1-20 carbon atoms and optionally containing a heteroatom substituent; L1 is selected from one of a hydrocarbon group having 1-10 carbon atoms, a pyridine substituent, a piperidine substituent, an alkyl ether substituent, an aryl ether substituent, an alkyl aryl ether substituent, a cyclic ether substituent, an alkyl nitrile derivative substituent, an alcohol substituent, an amide substituent, an aliphatic ester substituent, an aromatic ester substituent, an amine substituent, a halogen, and a cyclic unsaturated hydrocarbon substituent; or L1 and R7 form a ring with each other, and the ring optionally has a substituent;

[0020] R2, R5, and R6 are each independently selected from hydrogen, halogen, a hydrocarbon group having 1 to 30 carbon atoms and optionally containing a heteroatom or a heteroatom substituent, OR8, CO2R8, CO2A, C(O)N(R9)2, C(O)R8, SR8, SO2R8, SOR8, OSO2R8, P(O)(OR8) 2-y (R9) y , CN, NHR8, N(R8)2, Si(OR9) 3-x (R9) x 、OSi(OR9) 3-x (R9) x , NO2, SO3A, PO3A2, P(O)(OR8)2A and at least one of an epoxy-containing group, wherein the epoxy-containing group is a ring-containing C1-C6 alkyl group, and the number of ring carbon atoms in the oxygen-containing ring group is 2-10; R8 is selected from a hydrocarbon group having 1-20 carbon atoms, R9 is selected from hydrogen or a hydrocarbon group having 1-20 carbon atoms, A is selected from an alkali metal, an alkaline earth metal, ammonium, a quaternary ammonium or phosphonium, x is a natural number of 0-3, and y is a natural number of 0-2;

[0021] The heteroatoms are selected from oxygen, nitrogen, sulfur, phosphorus and silicon.

[0022] A second aspect of the present invention provides a method for preparing the metal complex as described above, the method comprising: reacting a compound represented by formula (III) with a complex C represented by the general formula ML′ to obtain a metal complex having a structure represented by formula (I);

[0023] Wherein, R' has the structure shown in formula (IV),

[0024] Wherein, the definitions of M and X, E1, R1, R1', R2, R3, R4, R5 and R6 in formula (III) and formula (IV) are the same as those in the first aspect;

[0025] Z is selected from hydrogen or a sulfinic acid group with a substituent, wherein the substituent is selected from hydrogen or C1-C 20 of hydrocarbon groups;

[0026] L' is the general formula (R 10 )p(L2)q, wherein R 10 L2 is selected from the group consisting of hydrogen, halogen, a hydrocarbon group having 1-20 carbon atoms and optionally containing a heteroatom substituent, L2 is selected from the group consisting of a hydrocarbon group having 1-10 carbon atoms, a pyridine substituent, a piperidine substituent, an alkyl ether substituent, an aryl ether substituent, an alkyl aryl ether substituent, a cyclic ether substituent, an alkyl nitrile derivative substituent, an alcohol substituent, an amide substituent, an aliphatic ester substituent, an aromatic ester substituent, an amine substituent, a halogen, and a cyclic unsaturated hydrocarbon substituent, and p and q are each independently an integer of 1-5;

[0027] Alternatively, L′ is two cyclooctadienyl ligands;

[0028] Alternatively, L' is three ligands, one of which is a cyclooctadienyl ligand, and the other two ligands are each independently selected from halogen and a hydrocarbon group having 1 to 10 carbon atoms.

[0029] The third aspect of the present invention provides use of the metal complex as described above in olefin copolymerization.

[0030] A fourth aspect of the present invention provides a method for preparing an olefin copolymer, the method comprising: copolymerizing a comonomer in the presence of a catalyst to obtain an olefin copolymer;

[0031] Wherein, the catalyst contains the metal complex described in the first aspect.

[0032] The metal complex provided by the present invention has significantly higher copolymerization activity when used to catalyze olefin copolymerization. In addition, the raw materials used to prepare the metal complex are cheap and low in toxicity, making it more suitable for use and having greater industrial application prospects. DETAILED DESCRIPTION

[0033] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0034] The following is a detailed description of the specific embodiments of the present invention. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention and are not intended to limit the present invention.

[0035] In a first aspect, the present invention provides a metal complex having a structure shown in formula (I):

[0036] Wherein, R has the structure shown in formula (II),

[0037] wherein M is selected from at least one of metals of Groups IVB, VB, VIB, VIIB and VIII, X is oxygen or sulfur, and E1 is nitrogen or phosphorus;

[0038] R1 and R1' are each independently selected from hydrogen, a hydrocarbon group having 1-20 (e.g., 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 20) carbon atoms and optionally containing a heteroatom substituent; or, R1, R1' and the central carbon atom in formula (I) (in formula (I), the central carbon atom connecting the two R groups and R1 and R1') together form a 5-8 (e.g., 5, 6, 7, 8) membered ring optionally containing a heteroatom substituent (i.e., the ring may or may not have a heteroatom substituent, and the ring may be an aliphatic ring, an aromatic ring, or a ring containing a heteroatom selected from oxygen, nitrogen, and sulfur, etc.);

[0039] R3 and R4 are each independently selected from hydrogen, a chain hydrocarbon group having 1 to 20 (e.g., 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 20) carbon atoms and optionally containing a substituent (e.g., a heteroatom substituent), and a 5-8 membered ring with or without a substituent containing a heteroatom;

[0040] R7 is selected from one of hydrogen, halogen, and a hydrocarbon group having 1-20 carbon atoms and optionally containing a heteroatom substituent; L1 is selected from one of a hydrocarbon group having 1-10 carbon atoms, a pyridine substituent, a piperidine substituent, an alkyl ether substituent, an aryl ether substituent, an alkyl aryl ether substituent, a cyclic ether substituent, an alkyl nitrile derivative substituent, an alcohol substituent, an amide substituent, an aliphatic ester substituent, an aromatic ester substituent, an amine substituent, a halogen, and a cyclic unsaturated hydrocarbon substituent; or L1 and R7 form a ring (which may form a ring having 4-10 carbon atoms), and the ring optionally has a substituent;

[0041] R2, R5, and R6 are each independently selected from hydrogen, halogen, a hydrocarbon group having 1 to 30 carbon atoms and optionally containing a heteroatom or a heteroatom substituent (which may be a chain hydrocarbon group or a 5-8 membered ring with or without a substituent), OR8, CO2R8, CO2A, C(O)N(R9)2, C(O)R8, SR8, SO2R8, SOR8, OSO2R8, P(O)(OR8) 2-y (R9) y , CN, NHR8, N(R8)2, Si(OR9) 3-x (R9) x 、OSi(OR9) 3-x (R9) x , NO2, SO3A, PO3A2, P(O)(OR8)2A and at least one of an epoxy-containing group, wherein the epoxy-containing group is an oxygen-containing cyclic C1-C6 alkyl group (it can be understood that the oxygen-containing cyclic group has at least one oxygen atom) and the number of ring carbon atoms in the oxygen-containing cyclic group is 2-10; R8 is selected from a hydrocarbon group having 1-20 carbon atoms, R9 is selected from hydrogen or a hydrocarbon group having 1-20 carbon atoms, A is selected from an alkali metal, an alkaline earth metal, ammonium, a quaternary ammonium or phosphonium, x is a natural number of 0-3, and y is a natural number of 0-2;

[0042] The heteroatoms are selected from oxygen, nitrogen, sulfur, phosphorus and silicon.

[0043] The inventors of the present invention have found in their research that the above-mentioned metal complex has significantly higher catalytic activity when used as a catalyst for olefin copolymerization.

[0044] According to the present invention, preferably, R1 and R1' are each independently selected from C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 Alkynyl and C6-C 20aryl, more preferably each independently methyl or trifluoromethyl; further preferably, R1 and R1' are the same;

[0045] Alternatively, R1, R1' and the central carbon atom in formula (I) together form a 6-membered ring (such as cyclohexyl).

[0046] According to the present invention, preferably, R2 is hydrogen or methyl, preferably hydrogen.

[0047] According to the present invention, preferably, R5 is hydrogen or methyl, preferably hydrogen.

[0048] According to the present invention, preferably, R6 is selected from hydrogen, methyl, anthracenyl, pyridyl, carbazolyl or a hydrocarbon group having 1 to 20 carbon atoms and having any number of fluorine substituents (for example, R6 can be pentafluorophenyl). When the R6 group is an electron-withdrawing group, the catalyst activity can be further improved, but the polymer molecular weight will be slightly reduced; when the R6 group is an electron-donating group, the polymer molecular weight will be further increased, but the catalyst activity will be slightly reduced. Those skilled in the art can select a suitable group according to actual needs.

[0049] According to the present invention, preferably, R3 is selected from C1-C 10 Alkyl, C2-C 10 Alkenyl, C2-C 10 Alkynyl, C6-C 20 One of the aryl groups, preferably phenyl or 2,6-dimethoxy-1-phenyl.

[0050] Preferably, R4 is selected from C1-C 10 Alkyl, C2-C 10 Alkenyl, C2-C 10 Alkynyl, C6-C 20 One of the aryl groups, preferably phenyl or 2,6-dimethoxy-1-phenyl.

[0051] The inventors of the present invention further discovered in their research that when R3 and R4 are selected from the above-mentioned substituents, the metal complex can effectively inhibit chain transfer when used in olefin copolymerization while ensuring sufficient reaction of the monomers.

[0052] According to the present invention, preferably, M is selected from nickel or palladium, more preferably nickel. The inventors of the present invention further discovered that when M is nickel, while ensuring that the metal complex has high catalytic activity when used in olefin polymerization, it can also significantly reduce costs, thus having obvious economic advantages.

[0053] According to the present invention, preferably, X is oxygen.

[0054] According to the present invention, preferably, E1 is phosphorus.

[0055] According to the present invention, preferably, R7 and L1 form a ring with each other to form a cyclooctenyl group; or, R7 is halogen, more preferably chlorine; L1 is C1-C 10 The hydrocarbon group is preferably a methyl group.

[0056] According to the present invention, preferably, the metal complex is selected from the group consisting of the following metal complexes:

[0057] Metal complex 1: M is nickel, X is oxygen, E1 is phosphorus, R1 and R1' are methyl groups, R3 and R4 are phenyl groups, R2, R5 and R6 are hydrogen atoms, and R7 and L1 form a cyclooctenyl ring.

[0058] Metal complex 2: M is nickel, X is oxygen, E1 is phosphorus, R1 and R1' are methyl groups, R3 and R4 are 2,6-dimethoxy-1-phenyl groups, R2, R5 and R6 are hydrogen atoms, and R7 and L1 form a cyclooctenyl ring.

[0059] Metal complex 3: M is nickel, X is oxygen, E1 is phosphorus, R1 and R1' are methyl groups, R3 and R4 are 2,6-dimethoxy-1-phenyl groups, R2 and R5 are hydrogen atoms, R6 is a methyl group, and R7 and L1 form a cyclooctenyl ring.

[0060] Metal complex 4: M is nickel, X is oxygen, E1 is phosphorus, R1 and R1' are methyl groups, R3 and R4 are 2,6-dimethoxy-1-phenyl groups, R2 and R5 are hydrogen atoms, R6 is anthracene group, and R7 and L1 form a cyclooctenyl ring.

[0061] Metal complex 5: M is nickel, X is oxygen, E1 is phosphorus, R1 and R1' are trifluoromethyl, R3 and R4 are phenyl, R2 and R5 are hydrogen, R6 is pyridyl, and R7 and L1 form a cyclooctenyl ring;

[0062] Metal complex 6: M is nickel, X is oxygen, E1 is phosphorus, R1 and R1' are methyl groups, R3 and R4 are 2,6-dimethoxy-1-phenyl groups, R2 and R5 are hydrogen atoms, R6 is pentafluorophenyl group, and R7 and L1 form a cyclooctenyl ring.

[0063] Metal complex 7: M is nickel, X is oxygen, E1 is phosphorus, R1 and R1' are methyl groups, R3 and R4 are phenyl groups, R2, R5 and R6 are hydrogen, R7 is chlorine, and L1 is methyl group;

[0064] Metal complex 8: M is palladium, X is oxygen, E1 is phosphorus, R1 and R1' together with the central carbon atom in formula (I) form a cyclohexyl group, R3 and R4 are phenyl groups, R2 and R5 are hydrogen, R6 is a carbazolyl group, R7 is chlorine, and L1 is a methyl group;

[0065] Metal complex 9: M is nickel, X is oxygen, E1 is phosphorus, R1 is methyl, R3 and R4 are 2,6-dimethoxy-1-phenyl, R2 and R5 are methyl, R6 is methyl, and R7 and L1 form a ring with each other to form a cyclooctenyl group.

[0066] In a second aspect, the present invention provides a method for preparing the metal complex as described above, the method comprising: reacting a compound represented by formula (III) with a complex C represented by the general formula ML′ to obtain a metal complex having a structure represented by formula (I);

[0067] Wherein, R' has the structure shown in formula (IV),

[0068] Wherein, the definitions of M and X, E1, R1, R1', R2, R3, R4, R5 and R6 in formula (III) and formula (IV) are the same as those in the first aspect;

[0069] Z is selected from hydrogen or a sulfinic acid group with a substituent, wherein the substituent is selected from hydrogen or C1-C 20 of hydrocarbon groups;

[0070] L' is the general formula (R 10 )p(L2)q, wherein R 10 L2 is selected from the group consisting of hydrogen, halogen, a hydrocarbon group having 1-20 carbon atoms and optionally containing a heteroatom substituent, L2 is selected from the group consisting of a hydrocarbon group having 1-10 carbon atoms, a pyridine substituent, a piperidine substituent, an alkyl ether substituent, an aryl ether substituent, an alkyl aryl ether substituent, a cyclic ether substituent, an alkyl nitrile derivative substituent, an alcohol substituent, an amide substituent, an aliphatic ester substituent, an aromatic ester substituent, an amine substituent, a halogen, and a cyclic unsaturated hydrocarbon substituent, and p and q are each independently an integer of 1-5;

[0071] Alternatively, L′ is two cyclooctadienyl ligands;

[0072] Alternatively, L' is three ligands, one of which is a cyclooctadienyl ligand, and the other two ligands are each independently selected from halogen and a hydrocarbon group having 1 to 10 carbon atoms (such as methyl).

[0073] According to the present invention, after the compound represented by formula (III) reacts with the complex C, the Z moiety can leave. The number of p and q is also based on maintaining the charge of the complex C at zero.

[0074] According to the present invention, preferably, the molar ratio of the compound represented by formula (III) to the complex C is 1:(0.01-99), more preferably 1:(2-10).

[0075] According to the present invention, preferably, the reaction conditions include: temperature of 0-100° C., and time of 1 s-24 h.

[0076] Further preferably, the reaction conditions include: a temperature of 20-60° C. (e.g., 20° C., 30° C., 40° C., 50° C., 60° C., and any range formed by any two of the above values, and values ​​within the range), and a time of 1-3 h (e.g., 1 h, 2 h, 3 h). The reaction can be carried out under stirring at a rate of 100-300 rpm.

[0077] According to the present invention, preferably, the reaction is carried out in the presence of a solvent and an inert gas, wherein the solvent is selected from toluene and / or (n-) hexane. The inert atmosphere refers to a gas that does not participate in the above reaction, for example, a nitrogen, helium or argon atmosphere. The amount of the solvent is not particularly limited, as long as it can fully disperse the reaction materials.

[0078] The complex C can be first dissolved in a solvent (such as toluene, with a mass ratio of complex C to solvent of 1 mg: (0.1-5) mL), and then the resulting solution and the compound represented by formula (III) (the compound represented by formula (III) can be used in solid form) are mixed. After the reaction is completed, the prepared metal complex can be separated from other components in the material obtained after the reaction (the separation method is not limited, as long as it does not affect the chemical structure of the metal complex, such as recrystallization) and then stored. Alternatively, the above separation can be omitted and the material obtained by the reaction can be directly stored. It can be stored in a high-purity nitrogen environment. When used for catalytic olefin copolymerization, the prepared pure metal complex can be used, or the material obtained after the above reaction can be directly used without purification.

[0079] According to the present invention, preferably, the complex C is selected from bis-1,5-cyclooctadiene nickel, chloro-1,5-cyclooctadiene-methyl-nickel or chloro-1,5-cyclooctadiene-methyl-palladium.

[0080] The method for obtaining the compound represented by formula (III) is not particularly limited and can be synthesized by itself. When the various groups therein are determined and the structure of the compound represented by formula (III) is completely determined, those skilled in the art can synthesize the compound. For example, when X is oxygen, E1 is phosphorus, R1 and R1' are methyl groups, R3 and R4 are phenyl groups, R2, R5 and R6 are hydrogen, and Z is hydrogen, the method for preparing the compound represented by formula (III) can be:

[0081] Under the condition of -40°C to -60°C, isopropylmagnesium chloride is slowly added (can be added dropwise, isopropylmagnesium chloride can be used in the form of a tetrahydrofuran solution) to a solution of iodobenzene in tetrahydrofuran (THF), then slowly warmed to room temperature and reacted for 0.5-2h, then the reaction solution is cooled to -60°C to -85°C, and phosphorus trichloride is slowly added (can be added dropwise), then slowly warmed to room temperature and reacted for 0.5-2h, and the solvent is removed under reduced pressure to obtain a first intermediate. Wherein, the amount of isopropylmagnesium chloride relative to 1g of iodobenzene can be 0.1-0.8g, and the amount of phosphorus trichloride can be 0.05-0.5g.

[0082] Dissolve bisphenol A in THF and add a strong base (such as NaH2O; the mass ratio of bisphenol A to NaH2O can be 10:2.5-4) at -5°C to 0°C with stirring. Allow to cool naturally to room temperature and react for 1.5-3 hours. Then, cool to -5°C to 0°C and slowly add chloromethyl methyl ether (the mass ratio of bisphenol A to chloromethyl methyl ether can be 10:7-8) dropwise. Allow to cool naturally to room temperature and react for 2-4 hours. After completion of the reaction, wash with water and extract with ethyl acetate. The organic phase is washed with a 0.5-1 mol / L KOH or NaOH solution (one to three washes are possible), followed by deionized water (one to three washes are possible). The organic phase is separated, dried over anhydrous sodium sulfate, and filtered. The filtrate is concentrated by rotary evaporation and purified using a silica gel column. The product is the second intermediate (also known as the hydroxyl-protected intermediate of bisphenol A).

[0083] The second intermediate is then dissolved in THF, and n-butyl lithium is slowly added dropwise at 0-3°C under an argon atmosphere (n-butyl lithium can be used as a toluene solution, and the mass ratio of the second intermediate to n-butyl lithium can be 1:(0.001-0.4) g). After returning to room temperature, the reaction is allowed to proceed for 2-4 hours, followed by cooling to 0-3°C. The first intermediate is dissolved in THF and slowly added dropwise to the reacted material (the mass ratio of the first intermediate to the second intermediate can be 1:(0.8-1.4)), and then returned to room temperature and allowed to react for 10-15 hours. Degassed saturated aqueous ammonium chloride is then added, and the organic phase is separated. The aqueous phase is extracted with ether and washed with brine. The organic phase is then dried over anhydrous sodium sulfate to obtain an ether solution. The ether solution can then be bubbled with HCl gas at -70 to 80°C for 20-30 minutes, then returned to room temperature, stirred for 10-15 hours, and then distilled to remove the solvent.

[0084] After distillation, the distilled material is redissolved in diethyl ether (the ratio of the distilled material to diethyl ether can be 1 g: (40 mL-60 mL)), bubbling NH3 gas at -70°C to 80°C for 25-35 minutes, and then naturally returning to room temperature and stirring for 10-15 hours. Then, after distilling the solvent, washing with an appropriate amount of n-hexane, removing solid impurities, and evaporating the solvent to dryness, the resulting material is the compound represented by formula (III).

[0085] In a third aspect, the present invention provides use of the metal complex as described above in olefin copolymerization.

[0086] In a fourth aspect, the present invention provides a method for preparing an olefin copolymer, the method comprising: copolymerizing a comonomer in the presence of a catalyst to obtain an olefin copolymer;

[0087] Wherein, the catalyst contains the metal complex as described above.

[0088] According to the present invention, preferably, the comonomer comprises α-olefin and acrylate.

[0089] α-olefins generally have a structure such as CH2=CHR 11 The structure of R 11 It may be hydrogen or a substituted or unsubstituted hydrocarbon group having 1 to 20 carbon atoms, and the hydrocarbon group may have a branch, a ring and / or an unsaturated bond.

[0090] Acrylates generally have a structure such as CH2=CHR 12 CO2R 13 The structure of R 12 It can be hydrogen or a hydrocarbon group having 1 to 10 carbon atoms, and the hydrocarbon group can have a branch, a ring and / or an unsaturated bond. 13 It can be hydrogen or a hydrocarbon group having 1 to 30 carbon atoms, which may have a branch, a ring and / or an unsaturated bond. 13 A heteroatom may be contained at any position therein.

[0091] According to a preferred embodiment of the present invention, the α-olefin is ethylene, and the acrylic acid ester is methyl methacrylate.

[0092] According to the present invention, the amount of catalyst used is preferably 0.1-0.6 mol, more preferably 0.2-0.4 mol (e.g., 0.2 mol, 0.3 mol, or 0.4 mol) per 100 mol of acrylate. The catalyst may be used in any form without particular limitation; for example, the catalyst may be used directly or supported on a carrier. The carrier is also not particularly limited and may, for example, be silica gel, clay, or other composite materials.

[0093] Preferably, the conditions of the copolymerization reaction include: a temperature of -20 to 290°C, preferably 20 to 60°C (for example, it can be 20°C, 30°C, 40°C, 50°C, 60°C and the range formed by any two of the above values ​​and the value within the range), a polymerization pressure of 0.1MPa-100MPa, preferably 0.1-1MPa, and a polymerization time of 1s-10h, preferably 1-3h (for example, it can be 1h, 2h, 3h). It can be understood that in the copolymerization reaction, acrylate and catalyst are generally added to the reaction vessel, and then ethylene is introduced into the system to maintain the reaction at a predetermined pressure. The amount of ethylene is based on maintaining the predetermined pressure. Generally, in order to maintain the pressure, the amount of ethylene introduced will be greater than the amount of ethylene that can participate in the copolymerization reaction.

[0094] The copolymerization reaction is carried out in an organic solvent that has been fully dehydrated and deoxygenated by any chemical or physical method. The organic solvent is preferably toluene or hexane.

[0095] The polymerization process and polymerization apparatus for the copolymerization reaction are not particularly limited. The polymerization process can be selected from slurry polymerization with a solvent (the solvent can be toluene), slurry bulk polymerization without a solvent and using the liquefied monomer itself as a medium, gas phase polymerization, and the like. The copolymerization reaction apparatus can be selected from batch reactor type, semi-batch type, and continuous type. After the copolymerization time is reached, nitrogen can be introduced into the reactor to blow out the ethylene and polar monomers that have not participated in the reaction to terminate the copolymerization reaction.

[0096] In the copolymerization reaction, one or more of the above metal complexes can be used. The inventors of the present invention have also found that when multiple metal complexes are used together, the molecular weight distribution can be broadened and the polar monomer insertion rate can be increased.

[0097] The present invention will be described in detail below through examples. In the following examples and comparative examples, unless otherwise specified, conventional methods are used; the reagents and materials described are all commercially available unless otherwise specified.

[0098] In the following examples, Ni(COD)2 represents bis-1,5-cyclooctadiene nickel (0), where 0 represents the valence state of nickel.

[0099] Example 1

[0100] 8 g of iodobenzene was dissolved in 100 mL of dry THF, and a THF solution of isopropylmagnesium chloride (2 mol / L, 16.5 mL) was slowly added dropwise at -50°C. The mixture was slowly warmed to room temperature with stirring and allowed to react for 1 hour. The mixture was then cooled to -78°C, and 2 g of phosphorus trichloride was slowly added dropwise. The mixture was slowly warmed to room temperature with stirring and allowed to react for 1 hour. The solvent was then removed under reduced pressure to obtain intermediate 1. The reaction equation is shown below.

[0101] Example 2

[0102] 8g of 2,6-dimethoxyiodobenzene was dissolved in 100mL of dry THF. A THF solution of isopropylmagnesium chloride (2 mol / L, 16.5mL) was slowly added dropwise at -50°C. The mixture was slowly warmed to room temperature with stirring and allowed to react for 1 hour. The mixture was then cooled to -78°C and 2g of phosphorus trichloride was slowly added dropwise. The mixture was slowly warmed to room temperature with stirring and allowed to react for 1 hour. The solvent was then removed under reduced pressure to obtain intermediate 2. The reaction equation is shown below.

[0103] Example 3

[0104] Dissolve 10g of bisphenol A in THF (100mL) and slowly add a THF solution of sodium hydride (2.91g NaH, 200mL THF) dropwise at 0°C with continuous stirring. Allow to react for 2 hours after naturally returning to room temperature. Then cool to 0°C and slowly add 7.76g of chloromethyl methyl ether dropwise. Allow to react for 3 hours after naturally returning to room temperature. After the reaction is complete, wash with water and extract with ethyl acetate. After extraction, the organic phase is washed once with a 1mol / L KOH solution and then twice with deionized water. After re-separating the organic phase, dry it with anhydrous sodium sulfate and filter it after drying. The filtrate is concentrated by rotary evaporation and purified simply by silica gel column. The product is the second intermediate.

[0105] The second intermediate 0.75g was dissolved in 30mL THF, and 1.2mL of n-butyllithium was slowly added dropwise to a toluene solution of n-butyllithium with a concentration of 2.5mol / L at 0°C in an argon atmosphere. The reaction was allowed to recover to room temperature naturally for 3 hours. The temperature was then lowered to 0°C, and 700mg of the intermediate 1 prepared in Example 1 was dissolved in 15mL THF, and the resulting solution was slowly added dropwise to the material after the above reaction, and the reaction was allowed to recover to room temperature naturally for 12 hours. 10mL of degassed saturated ammonium chloride aqueous solution was subsequently added, and the organic phase was separated. The aqueous phase was extracted with ether, and the organic phase was washed with brine. Anhydrous sodium sulfate was then used for drying.

[0106] HCl gas was bubbled into the ether solution obtained above at -78°C for 25 minutes. After the solution was naturally returned to room temperature and stirred for 12 hours, the solvent was distilled off.

[0107] After distillation, the product was redissolved in diethyl ether (1 g:50 mL), bubbling NH3 gas at -78°C for 30 minutes, allowing the mixture to naturally return to room temperature and stirring for 12 hours. After distilling the solvent, the mixture was washed with n-hexane to remove solid impurities, and the solvent was evaporated to dryness to obtain the compound represented by formula (III), whose structure is shown in formula (a) below.

[0108] Place 10 mg of the compound represented by formula (III) in a 5 mL reaction flask. Weigh 14 mg of Ni(COD)2 and mix with 10 mL of toluene to obtain a Ni(COD)2 toluene solution. Add 2 mL of the Ni(COD)2 toluene solution to the reaction flask (then the molar ratio of the compound represented by formula (III) to Ni(COD)2 is 1:2). Stir the mixture under a nitrogen atmosphere at 25°C for 1 hour (at a stirring rate of 200 rpm) and allow to stand until ready for use.

[0109] Example 4

[0110] The reaction was carried out in the manner of Example 3, except that the intermediate 1 prepared in Example 1 was replaced by the intermediate 2 prepared in Example 2; the molar ratio of the compound represented by formula (III) (structural formula is shown in formula (b) below) and Ni(COD)2 was 1:3, the reaction temperature was 20°C, and the mixture was stirred in a closed manner in a nitrogen atmosphere for 2 h (stirring rate was 200 rpm) and then allowed to stand for use.

[0111] Example 5

[0112] The procedure of Example 4 was followed, except that bisphenol A was replaced with methyl-modified bisphenol A as shown in formula (c). The resulting compound of formula (III) (shown in formula (d)) and was prepared in a molar ratio of 1:4. The reaction temperature was 30°C, and the mixture was stirred in a nitrogen atmosphere for 3 hours (at a stirring rate of 200 rpm) and then allowed to stand for use.

[0113] Example 6

[0114] The same method as in Example 4 was followed, except that bisphenol A was replaced with a molecule of the following formula (e). The structure of the compound of formula (III) obtained was shown in formula (f).

[0115] Example 7

[0116] The process was carried out in the same manner as in Example 3, except that bisphenol A was replaced with a molecule of the following formula (g). The structure of the compound of formula (III) obtained was shown in formula (h).

[0117] Example 8

[0118] The process was carried out in the same manner as in Example 4, except that bisphenol A was replaced with a molecule of the following formula (i). The structure of the compound of formula (III) obtained was shown in formula (j).

[0119] Example 9

[0120] The process was carried out in the same manner as in Example 3, except that Ni(COD)2 was replaced by (COD)1Ni(Me)1Cl.

[0121] Example 10

[0122] The same method as in Example 3 was used, except that bisphenol A was replaced with a molecule having the structure shown in Formula (k). The resulting compound of Formula (III) has the structure shown in Formula (l). Ni(COD)2 was replaced with (COD)1Pd(Me)1Cl.

[0123] Example 11

[0124] The process was carried out in the same manner as in Example 5, except that bisphenol A was replaced with a molecule having the structure shown in the following formula (m). The structure of the compound of formula (III) obtained was shown in formula (n).

[0125] Comparative Example 1

[0126] The catalyst in Example 9 of CN106632507B.

[0127] Comparative Example 2

[0128] The catalyst described in Example 25 of CN109320558A.

[0129] The metal complexes prepared in the above examples were characterized by H-NMR, C-NMR, and P-NMR spectra, and their structures were determined as shown in Table 1. In Table 1, taking the structure corresponding to Example 3 as an example, the phenyl group connected to P and the brackets with the subscript 2 indicate that P is connected to two phenyl groups.

[0130] Table 1

[0131] Test Case

[0132] The metal complex prepared in Example 3-11 was copolymerized in the following manner: anhydrous toluene (40 mL) and a predetermined amount of methyl methacrylate (MMA) were placed in an autoclave having a volume of approximately 100 mL and equipped with a stirring paddle. The autoclave was heated to a predetermined temperature under stirring, ethylene was introduced, and the temperature and pressure were adjusted to predetermined conditions. After the adjustment was completed, a catalyst was added for copolymerization. During the reaction, the amount of ethylene introduced was controlled to maintain the pressure in the autoclave at the corresponding value in the table. After reaching the predetermined polymerization time, nitrogen was introduced into the reactor to discharge unreacted gas. The solid reaction product was taken out and dried to a constant weight.

[0133] The product of Comparative Example 1 was operated according to the copolymerization reaction conditions of Example 9 in Table 1 of CN106632507B.

[0134] For the product of Comparative Example 2, the copolymerization steps in Example 25 of CN109320558A were followed.

[0135] The catalyst used, copolymerization pressure, MMA amount, copolymerization temperature and copolymerization time are shown in Table 2.

[0136] Table 2

[0137] For the products prepared by the above reactions, the following measurements were performed:

[0138] (1) Tm (melting point) and Tc (crystallization temperature): determined by DSC (differential scanning calorimeter) measurement:

[0139] Using a PYRIS Diamond DSC (PerkinElmer Inc.), a sample (approximately 5 mg) was melted at 210°C for 5 minutes, then the temperature was decreased to -20°C at a rate of 10°C / minute. After holding the temperature at -20°C for 5 minutes, the temperature was increased to 210°C at a rate of 10°C / minute to obtain a melting curve. The highest temperature of the main exothermic peak during the temperature decrease step was defined as the crystallization temperature, Tc. Furthermore, the peak top temperature of the main endothermic peak during the final temperature increase step for obtaining the melting curve was defined as the melting point, Tm.

[0140] (2) Weight average molecular weight Mw, number average molecular weight Mn and molecular weight distribution Mw / Mn, determined by GPC measurement:

[0141] First, a sample (approximately 20 mg) was collected in a vial for a high-temperature GPC pretreatment unit PL-SP 260VS manufactured by Polymer Laboratories Ltd. To this vial, o-dichlorobenzene (BHT concentration = 0.5 g / L) containing BHT (2,6-di-tert-butyl-4-methylphenol) as a stabilizer was added, and the polymer concentration was adjusted to 0.1 wt%. The polymer was dissolved in the high-temperature GPC pretreatment unit PL-SP 260VS by heating at 135°C and filtered through a glass filter to prepare a sample solution. No polymer was trapped by the glass filter during the GPC measurement. Next, GPC measurements were performed using a TSKgel GMH-HT column (30 cm x 4) manufactured by Tosoh Corp. and a GPCV2000RI detector manufactured by Waters. The following measurement conditions were used: sample solution injection volume: approximately 520 μL; column temperature: 135°C; solvent: o-dichlorobenzene; flow rate = 1.0 mL / min. Molecular weight was calculated as follows: Commercially available monodisperse polystyrene was used as a standard sample, and a calibration curve of retention time versus molecular weight was generated using the polystyrene standard sample and the viscosity formula for polyolefins. Molecular weight was calculated based on this calibration curve. The viscosity formula used was [η] = K × Mα, with K = 1.38E-4 and α = 0.70 for polystyrene, and K = 4.77E-4 and α = 0.70 for ethylene polymers.

[0142] In each copolymerization reaction, the catalyst activity Vp represents the ratio of the copolymer yield (kg) per hour to the metal content of the catalyst used in the copolymerization per mol. A larger Vp indicates a higher catalyst activity.

[0143] The results are shown in Table 3.

[0144] Table 3

[0145] The results in Table 3 show that the metal complex of the present invention has higher activity when catalyzing olefin copolymerization. In addition, the raw materials nickel and bisphenol A used in the preparation of the metal complex provided by the present invention are inexpensive and have low toxicity, making them more suitable for industrial applications.

[0146] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as disclosed in the present invention and fall within the scope of protection of the present invention.

Claims

1. A metal complex, characterized in that The metal complex has a structure shown in formula (I): Wherein, R has the structure shown in formula (II), wherein M is selected from at least one of metals of Group IVB, Group VB, Group VIB, Group VIIB and Group VIII, X is oxygen or sulfur, and E1 is nitrogen or phosphorus; R1 and R1' are each independently selected from hydrogen, a hydrocarbon group having 1 to 20 carbon atoms and optionally containing a heteroatom substituent; or, R1, R1' and the central carbon atom in formula (I) together form a 5-8 membered ring optionally containing a heteroatom substituent; R3 and R4 are each independently selected from hydrogen, a chain hydrocarbon group having 1 to 20 carbon atoms and optionally containing a substituent, and a 5-8 membered ring containing or not containing a heteroatom and having a substituent or no substituent; R7 is selected from one of hydrogen, halogen and a hydrocarbon group having 1-20 carbon atoms and optionally containing a heteroatom substituent; L1 is selected from one of a hydrocarbon group having 1-10 carbon atoms, a pyridine substituent, a piperidine substituent, an alkyl ether substituent, an aryl ether substituent, an alkyl aryl ether substituent, a cyclic ether substituent, an alkyl nitrile derivative substituent, an alcohol substituent, an amide substituent, an aliphatic ester substituent, an aromatic ester substituent, an amine substituent, a halogen and a cyclic unsaturated hydrocarbon substituent; or, L1 and R7 form a ring with each other, and the ring optionally has a substituent; R2, R5, R6 are each independently selected from hydrogen, halogen, a hydrocarbon group having 1 to 30 carbon atoms and optionally containing a heteroatom or a heteroatom substituent, OR8, CO2R8, CO2A, C(O)N(R9)2, C(O)R8, SR8, SO2R8, SOR8, OSO2R8, P(O)(OR8) 2-y (R9) y , CN, NHR8, N(R8)2, Si(OR9) 3-x (R9) x 、OSi(OR9) 3-x (R9) x , NO2, SO3A, PO3A2, P(O)(OR8)2A and at least one of an epoxy-containing group, wherein the epoxy-containing group is an oxygen-containing ring C1-C6 alkyl group and the number of ring carbon atoms of the oxygen-containing ring group is 2-10; R8 is selected from a hydrocarbon group having 1-20 carbon atoms, and R9 is selected from hydrogen or a hydrocarbon group having 1-20 carbon atoms. A is selected from alkali metal, alkaline earth metal, ammonium, quaternary ammonium or phosphonium, x is a natural number of 0-3, and y is a natural number of 0-2; The heteroatoms are selected from oxygen, nitrogen, sulfur, phosphorus and silicon.

2. The metal complex according to claim 1, wherein R1 and R1' are each independently selected from C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 Alkynyl and C6-C 20 The aromatic group, Alternatively, R1, R1' and the central carbon atom in formula (I) together form a 6-membered ring.

3. The metal complex according to claim 2, wherein R1 and R1' are each independently methyl or trifluoromethyl.

4. The metal complex according to claim 3, wherein R1 and R1' are the same.

5. The metal complex according to any one of claims 1 to 4, wherein R2 is hydrogen or methyl; and / or, R5 is hydrogen or methyl; and / or, R6 is selected from hydrogen, methyl, anthracenyl, pyridyl, carbazolyl or a hydrocarbon group having 1 to 20 carbon atoms and having any number of fluorine substituents; And / or, R3 is selected from C1-C 10 Alkyl, C2-C 10 Alkenyl, C2-C 10 Alkynyl, C6-C 20 One of the aromatic groups; and / or, R4 is selected from C1-C 10 Alkyl, C2-C 10 Alkenyl, C2-C 10 Alkynyl, C6-C 20 One of the aromatic groups; and / or, M is selected from nickel or palladium; and / or, X is oxygen; and / or, E1 is phosphorus; and / or, R7 and L1 are mutually cyclically cyclooctenyl; or, R7 is halogen; L1 is C1-C 10 of hydrocarbon groups.

6. The metal complex according to claim 5, wherein R2 is hydrogen; and / or, R5 is hydrogen; and / or, R3 is phenyl or 2,6-dimethoxy-1-phenyl; and / or, R4 is phenyl or 2,6-dimethoxy-1-phenyl; and / or, M is nickel; And / or, R7 and L1 form a ring with each other to form a cyclooctenyl group; or, R7 is chlorine; L1 is methyl.

7. The metal complex according to any one of claims 1 to 4, wherein The metal complex is selected from the group consisting of the following metal complexes: Metal complex 1: M is nickel, X is oxygen, E1 is phosphorus, R1 and R1' are methyl groups, R3 and R4 are phenyl groups, R2, R5 and R6 are hydrogen groups, and R7 and L1 are cyclically connected to form a cyclooctenyl group; Metal complex 2: M is nickel, X is oxygen, E1 is phosphorus, R1 and R1' are methyl groups, R3 and R4 are 2,6-dimethoxy-1-phenyl groups, R2, R5 and R6 are hydrogen, and R7 and L1 form a ring with each other to form a cyclooctenyl group; Metal complex 3: M is nickel, X is oxygen, E1 is phosphorus, R1 and R1' are methyl groups, R3 and R4 are 2,6-dimethoxy-1-phenyl groups, R2 and R5 are hydrogen, R6 is methyl group, and R7 and L1 are cyclically connected to form a cyclooctenyl group; Metal complex 4: M is nickel, X is oxygen, E1 is phosphorus, R1 and R1' are methyl groups, R3 and R4 are 2,6-dimethoxy-1-phenyl groups, R2 and R5 are hydrogen, R6 is anthracene, and R7 and L1 form a ring with each other to form a cyclooctenyl group; Metal complex 5: M is nickel, X is oxygen, E1 is phosphorus, R1 and R1' are trifluoromethyl, R3 and R4 are phenyl, R2 and R5 are hydrogen, R6 is pyridyl, and R7 and L1 form a ring with each other to form a cyclooctenyl; Metal complex 6: M is nickel, X is oxygen, E1 is phosphorus, R1 and R1' are methyl groups, R3 and R4 are 2,6-dimethoxy-1-phenyl groups, R2 and R5 are hydrogen groups, R6 is pentafluorophenyl group, and R7 and L1 are mutually cyclically formed into a cyclooctenyl group; Metal complex 7: M is nickel, X is oxygen, E1 is phosphorus, R1 and R1' are methyl groups, R3 and R4 are phenyl groups, R2, R5 and R6 are hydrogen groups, R7 is chlorine, and L1 is methyl group; Metal complex 8: M is palladium, X is oxygen, E1 is phosphorus, R1, R1' and the central carbon atom in formula (I) together form a cyclohexyl group, R3 and R4 are phenyl groups, R2 and R5 are hydrogen, R6 is a carbazolyl group, R7 is chlorine, and L1 is a methyl group; Metal complex 9: M is nickel, X is oxygen, E1 is phosphorus, R1 is methyl, R3 and R4 are 2,6-dimethoxy-1-phenyl, R2 and R5 are methyl, R6 is methyl, and R7 and L1 form a cyclooctenyl ring.

8. A method for preparing the metal complex according to any one of claims 1 to 7, characterized in that: The method comprises: reacting a compound represented by formula (III) with a complex C represented by the general formula ML′ to obtain a metal complex having a structure represented by formula (I); Wherein, R' has the structure shown in formula (IV), Wherein, the definitions of M and X, E1, R1, R1', R2, R3, R4, R5 and R6 in formula (III) and formula (IV) are the same as those in claims 1 to 7; Z is selected from hydrogen or a sulfinic acid group with a substituent, wherein the substituent is selected from hydrogen or C1-C 20 The hydrocarbon group; L' is the general formula (R 10 )p(L2)q, wherein R 10 is selected from hydrogen, halogen, a hydrocarbon group having 1-20 carbon atoms and optionally containing a heteroatom substituent, L2 is selected from a hydrocarbon group having 1-10 carbon atoms, a pyridine substituent, a piperidine substituent, an alkyl ether substituent, an aryl ether substituent, an alkyl aryl ether substituent, a cyclic ether substituent, an alkyl nitrile derivative substituent, an alcohol substituent, an amide substituent, an aliphatic ester substituent, an aromatic ester substituent, an amine substituent, a halogen and a cyclic unsaturated hydrocarbon substituent, and p and q are each independently an integer of 1-5; Alternatively, L′ is two cyclooctadienyl ligands; Alternatively, L' is three ligands, one of which is a cyclooctadienyl ligand, and the other two ligands are each independently selected from halogen and a hydrocarbon group having 1 to 10 carbon atoms.

9. The method according to claim 8, wherein: The molar ratio of the compound represented by formula (III) to the complex C is 1:(0.01-99); And / or, the reaction conditions include: temperature of 0-100°C, time of 1s-24h; And / or, the reaction is carried out in the presence of a solvent and in an inert gas atmosphere, and the solvent is selected from toluene and / or hexane.

10. The method according to claim 9, wherein: The molar ratio of the compound represented by formula (III) to the complex C is 1:(2-10); And / or, the reaction conditions include: temperature of 20-60° C., and time of 1-3 h.

11. The method according to claim 9 or 10, wherein: The complex C is selected from bis-1,5-cyclooctadiene nickel, chloro-1,5-cyclooctadiene-methyl-nickel or chloro-1,5-cyclooctadiene-methyl-palladium.

12. Use of the metal complex according to any one of claims 1 to 7 in olefin copolymerization.

13. A method for preparing an olefin copolymer, characterized in that: The method comprises: in the presence of a catalyst, copolymerizing a comonomer to obtain an olefin copolymer; Wherein, the catalyst contains the metal complex described in any one of claims 1-7.

14. The method according to claim 13, wherein: The comonomer comprises an α-olefin and an acrylate; And / or, the copolymerization reaction conditions include: temperature of -20°C to 290°C, polymerization pressure of 0.1MPa-100MPa, and polymerization time of 1s-10h.

15. The method according to claim 14, wherein: The α-olefin is ethylene, and the acrylic acid ester is methyl methacrylate; and / or, the amount of the catalyst is 0.1-0.6 mol relative to 100 mol of acrylate; And / or, the copolymerization reaction conditions include: temperature of 20 to 60° C., polymerization pressure of 0.1-1 MPa, and polymerization time of 1-3 h.

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