Metal complex as well as preparation method and application thereof

Abstract

The invention relates to the technical field of olefin polymerization, and discloses a metal complex as well as a preparation method and application thereof. The structural formula of the metal complex is shown as a formula (I). The preparation method of the metal complex comprises the following steps: (1) carrying out coupling reaction on a pyridine aldehyde compound and naphthaleneboronic acid to obtain a 2-naphthyl-pyridine aldehyde compound; (2) carrying out condensation reaction on the 2-naphthyl-pyridine aldehyde compound and 9-aminofluorene to obtain a pyridine imine compound; (3) carrying out reduction reaction on the pyridine imine compound and a reducing agent (R2) mM1 to obtain a pyridine amine compound ligand; and (4) reacting the pyridylamino compound ligand with a hydrogen pulling agent to generate a salt, and then carrying out a complexation reaction with a metal salt of M. The metal complex provided by the invention can still maintain high ethylene (co) polymerization activity at a high temperature.

Description

Technical Field

[0001] This invention relates to the field of olefin polymerization technology, specifically to a metal complex, its preparation method, and its application. Background Technology

[0002] Polymer materials are the backbone of modern science and technology and social development, and have become indispensable materials in cutting-edge technology, national defense, and various fields of the national economy. Among them, polyolefins are the fastest-growing, highest-volume, and most widely used synthetic resins, playing an irreplaceable role in many fields such as military, industry, agriculture, and medical and health care. Polyethylene is the most widely used polyolefin material, such as polyolefin elastomers based on ethylene / α-olefins (propylene, 1-butene, 1-hexene, 1-octene, etc.), which possess the plasticity of plastics and the high elasticity of rubber, and are currently one of the main directions for the development of high-end polyolefin materials.

[0003] The research and industrialization of olefin polymerization catalysts are crucial to the development of the polyolefin industry. Driven by the substantial market demand for novel polyolefin materials, the design and development of new polyolefin catalysts to innovate polymer structures and properties has become a hot topic in academia and industry. Metal complexes as catalysts for olefin polymerization are currently the most important method in polyolefin catalyst scientific research, mainly including homogeneous and heterogeneous catalysts. Currently, industrialized polyolefin catalysts are mainly Ziegler-Natta type catalysts, metallocene catalysts, and, in recent years, transition metal complex-type high-efficiency ethylene homopolymerization and copolymerization catalysts.

[0004] Among the many types of polyolefin catalysts, homogeneous pre-transition metal catalysts have attracted much attention due to their high polymerization activity, high molecular weight of the resulting polymers, ability to achieve living polymerization, and controllability (see, for example, Angew. Chem. Int. Ed. 2020, 59, 14726-147; Chemical Bulletin, 2014, 77, 951-960). By changing the steric hindrance effect, electronic effect, and number of metal centers near the active site, the polymerization activity, polymerization products, and product distribution can be controlled.

[0005] Among them, pyridine-amine hafnium catalysts, first developed by Symyx, have shown excellent catalytic performance in olefin polymerization, exhibiting high activity in ethylene polymerization to produce linear polyethylene. They also demonstrate good copolymerization properties, catalyzing the copolymerization of ethylene and α-olefins to produce polyolefin elastomers with high α-olefin insertion rates. In particular, they can also catalyze the copolymerization of ethylene and octene with former transition metal zirconium catalysts to produce polyolefin block copolymers. DOW Chemicals has successfully prepared commercially viable high-performance polyolefin block copolymers (OBCs) using pyridine-amine hafnium catalysts via chain shuttle polymerization technology, drawing widespread attention to pyridine-amine group IVB metal catalysts in the polyolefin field. The structure of pyridine-amine catalysts has a significant impact on their catalytic performance. Substituents at the ortho position of the aromatic amine can affect the catalyst activity and polymer molecular weight. Furthermore, sterically hindered substituents can bring the aromatic amine group closer to the coordinated monomer, significantly influencing the monomer insertion mode and the stereoregularity of the polymer. By controlling the catalyst's skeletal structure, its olefin (co)polymerization performance can be effectively regulated. However, the lack of high-performance olefin polymerization catalysts remains a major factor limiting development in the production of high-end polyolefins. Some catalysts have low α-octene insertion rates and relatively low polymerization temperatures, making it difficult to meet the basic requirements of elastomers and the requirements of industrial solution polymerization processes. Summary of the Invention

[0006] To overcome the shortcomings of existing technologies, the inventors of this invention conducted extensive research. The results showed that introducing a sterically hindered fluorene group onto the aromatic amine of a pyridine-amine complex can significantly improve the activity and stability of the catalyst. This metal complex maintains high ethylene polymerization activity even at higher temperatures and can catalyze olefin homopolymerization, ethylene / α-olefin copolymerization, and especially the copolymerization of ethylene with higher α-olefins (such as 1-octene). Polymers prepared using this metal complex exhibit high molecular weight, narrow molecular weight distribution, high catalytic activity, and high monomer insertion rate.

[0007] The first aspect of this invention provides a metal complex with the structural formula shown in formula (I).

[0008]

[0009] Among them, R 1 With R 2 Same or different, and R 1 and R 2 Each is independently selected from hydrogen and C1-C30 hydrocarbon groups;

[0010] n is 1 or 2. When n is 2, R 3 It is a halogen or a monovalent substituent having 1-20 atoms other than hydrogen; when n is 1, R3 It is a divalent substituent having 1-40 atoms other than hydrogen;

[0011] M is selected from group IVB metals.

[0012] Preferably, R 1 and R 2 Each is independently selected from hydrogen, C1-C20 alkyl or cycloalkyl, C2-C6 olefin, C1-C20 alkoxy, C3-20 cycloalkyloxy, C6-30 aryl or substituted aryl and C6-30 aryloxy.

[0013] Preferably, R 1 and R 2 One of them is hydrogen.

[0014] Preferably, when n is 2, the two R 3 Each is independently selected from halogens, alkyl groups, substituted alkyl groups, aryl groups, and substituted aryl groups; when n is 1, R 3 It is 1,3-butadiene or 1,3-pentadiene directly coordinated with metal M or formed a covalent bond.

[0015] Preferably, M is titanium, zirconium, or hafnium.

[0016] Preferably, the metal complex is selected from the group consisting of the following complexes:

[0017] Complex 1: The complex shown in formula (I), where M is Hf and R is... 1 For H, R 2 It is 2-isopropylphenyl, R 3 It is a methyl group, and n is 2;

[0018] Complex 2: The complex shown in formula (I), where M is Hf and R is... 1 For H, R 2 It is 2-cyclohexylphenyl, R 3 It is a methyl group, and n is 2;

[0019] Complex 3: The complex shown in formula (I), where M is Hf and R is... 1 For H, R 2 It is isopropyl, R 3 It is a methyl group, and n is 2;

[0020] Complex 4: The complex shown in formula (I), where M is Hf and R is... 1 For H, R 2 It is a phenyl group, R 3 It is a methyl group, and n is 2;

[0021] Complex 5: The complex shown in formula (I), where M is Hf and R is... 1 For H, R 2It is 2-methylphenyl, R 3 It is a methyl group, and n is 2;

[0022] Complex 6: The complex shown in formula (I), where M is Hf and R is... 1 For H, R 2 It is 2-cyclohexylphenyl, R 3 It is benzyl, and n is 2;

[0023] Complex 7: The complex shown in formula (I), where M is Hf and R is... 1 For H, R 2 It is naphthyl, R 3 It is benzyl, and n is 2;

[0024] Complex 8: The complex shown in formula (I), where M is Hf and R is... 1 For H, R 2 It is 2,4-dimethoxyphenyl, R 3 It is benzyl, and n is 2;

[0025] Complex 9: The complex shown in formula (I), where M is Zr and R is R. 1 For H, R 2 It is 2-isopropylphenyl, R 3 It is a methyl group, and n is 2.

[0026] A second aspect of the present invention provides a method for preparing the above-mentioned metal complex, the method comprising the following steps:

[0027] (1) In an organic solvent, the pyridinaldehyde compound of formula (II) is coupled with naphthaleneboronic acid to obtain the 2-naphthyl-pyridinaldehyde compound of formula (IⅡ);

[0028] (2) In an organic solvent, the 2-naphthyl-pyridinaldehyde compound is condensed with 9-aminofluorene to obtain the pyridinimine compound shown in formula (IV);

[0029] (3) In an organic solvent, the pyridineimine compound is reacted with a reducing agent (R) 2 ) m M1 undergoes a reduction reaction to yield the pyridine amino compound ligand shown in formula (V);

[0030] (4) In an organic solvent, the pyridine amino compound ligand is first reacted with a dehydrogenating agent to generate a salt, and then complexed with the metal salt of M.

[0031]

[0032]

[0033] Among them, R 1Selected from hydrogen and C1-C30 hydrocarbon groups; R 2 It is a C1-C30 hydrocarbon group; X is a halogen; M is selected from group IVB metals; M1 is Li, Al or Na; m is an integer from 1 to 3.

[0034] Preferably, in formula (II), X is bromine.

[0035] Preferably, in step (3), the reducing agent is trialkylaluminum and / or aryllithium.

[0036] Preferably, in step (4), the hydrogen-removing agent is one or more of sodium hydride, potassium hydride, lithium hydride, tetramethylethylenediamine, bis(trimethylsilylamino)lithium, bis(trimethylsilylamino)sodium, diisopropylaminolithium and C1-C6 alkyllithium.

[0037] Preferably, in step (4), the metal salt of M is at least one of a halide of metal M and an alkyl compound of metal M.

[0038] Preferably, in steps (1) to (4), the organic solvents used are each independently selected from one or more of tetrahydrofuran, anhydrous diethyl ether, pentane, cyclopentane, n-hexane, cyclohexane, heptane, methylcyclohexane, toluene, xylene, chlorobenzene and o-dichlorobenzene.

[0039] Preferably, in step (4), the molar ratio of the pyridine amino compound ligand shown in formula (V) to the dehydrogenating agent is 1:(0.8-2), more preferably 1:(1-1.5).

[0040] Preferably, the reaction conditions for salt formation include: a temperature of -78°C to 35°C, more preferably -78°C to 0°C; and a time of 1-24 hours.

[0041] Preferably, the molar ratio of the pyridine amino compound ligand shown in formula (V) to the metal salt of M, based on the amount of metal ions, is 1:(1-2), more preferably 1:(1.05-1.5).

[0042] Preferably, the conditions for the complexation reaction include: a temperature of 60°C to 120°C and a time of 4-30 hours.

[0043] A third aspect of the present invention provides an olefin polymerization catalyst comprising a main catalyst and a co-catalyst, wherein the main catalyst is the metal complex described above.

[0044] Preferably, the cocatalyst is an organoaluminum compound, or a combination of an organoaluminum compound and an organoboride.

[0045] Preferably, the organoboron compound is selected from triethylammonium tetra(phenyl)boron, tributylammonium tetra(phenyl)boron, trimethylammonium tetra(phenyl)boron, tripropylammonium (phenyl)boron, trimethylammonium tetra(p-methylphenyl)boron, trimethylammonium tetra(o,p-dimethylphenyl)boron, tributylammonium tetra(p-trifluoromethylphenyl)boron, trimethylammonium tetra(p-trifluoromethylphenyl)boron, tributylammonium tetra(pentafluorophenyl)boron, N,N-diethylaniline tetra(phenyl)boron, N,N-diethylaniline tetra(pentafluorophenyl)boron, diethylaniline tetra(pentafluorophenyl)boron, trimethylphosphine tetra(phenyl)boron, and tripropylammonium tetra(p-tolyl). At least one of boron, triethylammonium tetra(p-trifluoromethylphenyl)boron, triethylammonium tetra(o,p-dimethylphenyl)boron, trimethylammonium tetra(o,p-dimethylphenyl)boron, tributylammonium tetra(p-trifluoromethylphenyl)boron, trimethylammonium tetra(p-trifluoromethylphenyl)boron, tributylammonium tetra(pentafluorophenyl)boron, triphenylphosphine tetra(phenyl)boron, tri(pentafluorophenyl)borane, triphenylcarbium tetra(pentafluorophenyl)boron, triphenylcarbium tetra(p-trifluoromethylphenyl)boron, N,N-dimethylaniline tetra(pentafluorophenyl)boron, triphenylcarbium tetra(pentafluorophenyl)borate, and N,N-dimethylaniline tetra(pentafluorophenyl)borate.

[0046] Preferably, the organoaluminum compound is at least one selected from trimethylaluminum, triethylaluminum, triisobutylaluminum, tripropylaluminum, tributylaluminum, dimethylaluminum chloride, triisopropylaluminum, trisec-butylaluminum, tripentylaluminum, triisopentylaluminum, tricyclopentylaluminum, trihexylaluminum, trioctylaluminum, ethyldimethylaluminum, methyldiethylaluminum, triphenylaluminum, tri-p-methylphenylaluminum, dimethylmethoxyaluminum, methylaluminoxane, and modified methylaluminoxane.

[0047] Preferably, the molar ratio Al / M of aluminum in the co-catalyst to metal M in the metal complex is 1-10000, and the molar ratio B / M of boron in the co-catalyst to metal M in the metal complex is 0-10.

[0048] A fourth aspect of the present invention provides a method for olefin polymerization, the method comprising: carrying out an olefin polymerization reaction in the presence of the olefin polymerization catalyst described above.

[0049] Preferably, the conditions for the olefin polymerization reaction include: a temperature of -78℃ to 200℃, more preferably -20℃ to 150℃; and a pressure of 0.01 to 10 MPa, more preferably 0.01 to 5 MPa.

[0050] According to the technical solution of this invention, by introducing a sterically hindered fluorene group onto the aromatic amine of a pyridine-amine complex, a new metal complex is formed. When used as the main catalyst for olefin polymerization, this complex maintains high ethylene polymerization activity at higher temperatures and can catalyze olefin homopolymerization, ethylene / α-olefin copolymerization, and especially the copolymerization of ethylene with higher α-olefins (such as 1-octene). The polymerization products prepared using this metal complex exhibit high molecular weight, narrow molecular weight distribution, high catalytic activity, and high monomer insertion rate.

[0051] Compared with the prior art, the advantages of the technical solution of the present invention are as follows:

[0052] (1) The introduction of fluorene group on the metal complex of the present invention is simple, the synthesis of metal complex is simple and efficient, and the yield of the target metal complex from pyridine aldehyde compound raw material exceeds 70%.

[0053] (2) In the metal complex of the present invention, by introducing a sterically hindered fluorene group onto the aromatic amine skeleton of the pyridine amino complex, the polymerization of ethylene can be catalyzed with high activity, and in particular, the polymerization activity can be maintained at higher polymerization temperatures.

[0054] (3) Using the metal complex described in this invention as the main catalyst for olefin polymerization has higher copolymerization performance of ethylene and α-olefin. Detailed Implementation

[0055] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0056] The structural formula of the metal complex described in this invention is shown in formula (I).

[0057]

[0058] Among them, R 1 With R 2 Same or different, and R 1 and R 2 Each is independently selected from hydrogen and C1-C30 hydrocarbon groups;

[0059] n is 1 or 2. When n is 2, R 3 It is a halogen or a monovalent substituent having 1-20 atoms other than hydrogen; when n is 1, R 3 It is a divalent substituent having 1-40 atoms other than hydrogen;

[0060] M is selected from group IVB metals.

[0061] In the preferred case, R 1 and R2 Each is independently selected from hydrogen, C1-C20 alkyl or cycloalkyl, C2-C6 olefin, C1-C20 alkoxy, C3-20 cycloalkyloxy, C6-30 aryl or substituted aryl, and C6-30 aryloxy. More preferably, R 1 and R 2 One of them is hydrogen, for example, R 1 For hydrogen, R 2 It can be a C1-C6 alkyl or cycloalkyl, a C2-C6 olefin, a C6-10 aryl or substituted aryl, or a C6-10 aryloxy group.

[0062] In this invention, the C1-C6 alkyl or cycloalkyl groups can be selected from methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, n-pentyl, isopentyl, n-hexyl, isohexyl, 3,3-dimethylbutyl or cyclohexyl.

[0063] In this invention, the C2-C6 olefin group can be selected from vinyl, n-propenyl, isopropenyl, n-butenyl, isobutenyl, n-pentenyl, isopentenyl, n-hexenyl or isohexenyl.

[0064] In this invention, C6-10 aryl or substituted aryl and C6-10 aryloxy can be selected from phenyl, naphthyl, 4-methylphenyl, 4-ethylphenyl, 2-isopropylphenyl, dimethylphenyl, vinylphenyl or 2,4-dimethoxyphenyl.

[0065] In some implementations, when n is 2, the two R 3 Each is independently selected from halogens, alkyl groups, substituted alkyl groups, aryl groups, and substituted aryl groups. More preferably, both R groups are selected from halogens, alkyl groups, substituted alkyl groups, aryl groups, and substituted aryl groups. 3 Each is independently selected from halogens, methyl, benzyl, and phenyl.

[0066] In other implementations, when n is 1, R 3 It is 1,3-butadiene or 1,3-pentadiene directly coordinated with metal M or formed a covalent bond.

[0067] In preferred cases, M is titanium, zirconium, or hafnium.

[0068] In a further preferred embodiment, the metal complex is selected from the group consisting of:

[0069] Complex 1: The complex shown in formula (I), where M is Hf and R is... 1 For H, R 2 It is 2-isopropylphenyl, R 3 It is a methyl group, and n is 2;

[0070] Complex 2: The complex shown in formula (I), where M is Hf and R is... 1 For H, R2 It is 2-cyclohexylphenyl, R 3 It is a methyl group, and n is 2;

[0071] Complex 3: The complex shown in formula (I), where M is Hf and R is... 1 For H, R 2 It is isopropyl, R 3 It is a methyl group, and n is 2;

[0072] Complex 4: The complex shown in formula (I), where M is Hf and R is... 1 For H, R 2 It is a phenyl group, R 3 It is a methyl group, and n is 2;

[0073] Complex 5: The complex shown in formula (I), where M is Hf and R is... 1 For H, R 2 It is 2-methylphenyl, R 3 It is a methyl group, and n is 2;

[0074] Complex 6: The complex shown in formula (I), where M is Hf and R is... 1 For H, R 2 It is 2-cyclohexylphenyl, R 3 It is benzyl, and n is 2;

[0075] Complex 7: The complex shown in formula (I), where M is Hf and R is... 1 For H, R 2 It is naphthyl, R 3 It is benzyl, and n is 2;

[0076] Complex 8: The complex shown in formula (I), where M is Hf and R is... 1 For H, R 2 It is 2,4-dimethoxyphenyl, R 3 It is benzyl, and n is 2;

[0077] Complex 9: The complex shown in formula (I), where M is Zr and R is R. 1 For H, R 2 It is 2-isopropylphenyl, R 3 It is a methyl group, and n is 2.

[0078] The present invention also provides a method for preparing the above-mentioned metal complex, the method comprising the following steps:

[0079] (1) In an organic solvent, the pyridinaldehyde compound of formula (II) is coupled with naphthaleneboronic acid to obtain the 2-naphthyl-pyridinaldehyde compound of formula (IⅡ);

[0080] (2) In an organic solvent, the 2-naphthyl-pyridinaldehyde compound is condensed with 9-aminofluorene to obtain the pyridinimine compound shown in formula (IV);

[0081] (3) In an organic solvent, the pyridineimine compound is reacted with a reducing agent (R) 2 ) m M1 undergoes a reduction reaction to yield the pyridine amino compound ligand shown in formula (V);

[0082] (4) In an organic solvent, the pyridine amino compound ligand is first reacted with a dehydrogenating agent to generate a salt, and then complexed with the metal salt of M.

[0083]

[0084]

[0085] Among them, R 1 Selected from hydrogen and C1-C30 hydrocarbon groups; R 2 It is a C1-C30 hydrocarbon group; X is a halogen; M is selected from group IVB metals; M1 is Li, Al or Na; m is an integer from 1 to 3.

[0086] In formula (II), X is preferably chlorine or bromine, more preferably bromine. As an example, the pyridine aldehyde compound used in step (1) may be 6-bromopyridine-2-carboxaldehyde and / or 6-chloropyridine-2-carboxaldehyde.

[0087] In step (1), the coupling reaction between the pyridinaldehyde compound and naphthaleneboronic acid is shown in the following formula.

[0088]

[0089] In step (1), the coupling reaction is carried out in the presence of a catalyst. The catalyst used may be at least one of tetra(triphenylphosphine)palladium, bis(triphenylphosphine)palladium dichloride, bis(tri-tert-butylphosphine)palladium, and [1,1'-bis(diphenylphosphine)ferrocene]palladium dichloride.

[0090] In step (1), the molar ratio of the pyridine aldehyde compound to naphthaleneboronic acid can be 1:(0.5-2), preferably 1:(0.8-1.2), and most preferably 1:1.

[0091] In step (2), the condensation reaction between the 2-naphthyl-pyridinaldehyde compound and 9-aminofluorene is shown in the following formula.

[0092]

[0093] In step (2), the condensation reaction is carried out in the presence of a catalyst. The catalyst used may be at least one of p-toluenesulfonic acid, formic acid, and acetic acid.

[0094] In step (2), the molar ratio of the 2-naphthyl-pyridinaldehyde compound to 9-aminofluorene can be 1:(0.8-2), preferably 1:(1.01-1.2).

[0095] In step (3), the pyridineimine compound reacts with the reducing agent (R) 2 ) m The process of the reduction reaction of M1 is shown in the following equation.

[0096]

[0097] In step (3), the reducing agent (R) 2 ) m In M1, m represents the valence state of metal M1, which can be an integer from 1 to 3.

[0098] In step (3), preferably, the reducing agent is trialkylaluminum and / or aryllithium. Specific examples of the trialkylaluminum may be at least one of trimethylaluminum, triethylaluminum, and triisobutylaluminum. Specific examples of the aryllithium may be at least one of phenyllithium, naphthyllithium, 2-methylphenyllithium, 2-isopropylphenyllithium, 2,4-dimethoxyphenyllithium, and 2-cyclohexylphenyllithium.

[0099] In step (3), the pyridineimine compound reacts with the reducing agent (R) 2 ) m The molar ratio of M1 can be 1:(1-2), preferably 1:(1.1-1.5).

[0100] In step (4), the dehydrogenating agent may be one or more of sodium hydride, potassium hydride, lithium hydride, tetramethylethylenediamine, bis(trimethylsilylamino) lithium, bis(trimethylsilylamino) sodium, diisopropylamino lithium, and C1-C6 alkyl lithium, preferably n-butyllithium.

[0101] In step (4), the metal salt of M can be at least one of a halide of metal M and an alkyl compound of metal M, preferably at least one of hafnium tetrachloride, tetrabenzyl hafnium and zirconium tetrachloride.

[0102] In step (4), the molar ratio of the pyridine amino compound ligand shown in formula (V) to the dehydrogenating agent can be 1:(0.8-2), preferably 1:(1-1.5), and more preferably 1:(1.01-1.2).

[0103] In step (4), the molar ratio of the pyridine amino compound ligand shown in formula (V) to the metal salt of M, based on the amount of metal ions, can be 1:(1-2), preferably 1:(1.05-1.5), and more preferably 1:(1.1-1.2).

[0104] In step (4), the conditions for the reaction to generate salt may include: a temperature of -78°C to 35°C, preferably -78°C to 0°C; and a time of 1-24h.

[0105] In step (4), the conditions for the complexation reaction may include: a temperature of 60°C to 120°C and a time of 4-30h.

[0106] In steps (1) to (4), the organic solvents used may be selected independently from one or more of tetrahydrofuran, anhydrous diethyl ether, pentane, cyclopentane, n-hexane, cyclohexane, heptane, methylcyclohexane, toluene, xylene, chlorobenzene and o-dichlorobenzene.

[0107] Steps (1) to (4) each further include a product separation process. In a preferred embodiment, steps (1) to (4) each independently employ column chromatography or recrystallization to separate and purify the product.

[0108] The present invention also provides an olefin polymerization catalyst, which comprises a main catalyst and a co-catalyst, wherein the main catalyst is a metal complex provided by the present invention.

[0109] In the olefin polymerization catalyst of the present invention, the co-catalyst is an organoaluminum compound, or a combination of an organoaluminum compound and an organoboride.

[0110] In this invention, the organoboron compound can be an aromatic boron and / or an organoborate. Specifically, the organoboron compound can be selected from triethylammonium tetra(phenyl)boron, tributylammonium tetra(phenyl)boron, trimethylammonium tetra(phenyl)boron, tripropylammonium (phenyl)boron, trimethylammonium tetra(p-methylphenyl)boron, trimethylammonium tetra(o,p-dimethylphenyl)boron, tributylammonium tetra(p-trifluoromethylphenyl)boron, trimethylammonium tetra(p-trifluoromethylphenyl)boron, tributylammonium tetra(pentafluorophenyl)boron, N,N-diethylaniline tetra(phenyl)boron, N,N-diethylaniline tetra(pentafluorophenyl)boron, diethylaniline tetra(pentafluorophenyl)boron, trimethylphosphine tetra(phenyl)boron, tripropylammonium tetra(p-tolyl)boron, and tripropylammonium tetra(p-tolyl)boron. The organoboron compound is at least one of the following: triethylammonium tetra(p-trifluoromethylphenyl)boron, triethylammonium tetra(o-,p-dimethylphenyl)boron, trimethylammonium tetra(o-,p-dimethylphenyl)boron, tributylammonium tetra(p-trifluoromethylphenyl)boron, trimethylammonium tetra(p-trifluoromethylphenyl)boron, tributylammonium tetra(pentafluorophenyl)boron, triphenylphosphine tetra(phenyl)boron, tri(pentafluorophenyl)borane, triphenylcarbium tetra(pentafluorophenyl)boron, triphenylcarbium tetra(p-trifluoromethylphenyl)boron, N,N-dimethylaniline tetra(pentafluorophenyl)boron, triphenylcarbium tetra(pentafluorophenyl)borate, and N,N-dimethylaniline tetra(pentafluorophenyl)borate. More preferably, the organoboron compound is at least one of tri(pentafluorophenyl)borane, triphenylcarbium tetra(pentafluorophenyl)borate, and N,N-dimethylaniline tetra(pentafluorophenyl)borate.

[0111] In this invention, the organoaluminum compound can be selected from alkylaluminoxanes and compounds with the general formula AlY. n Z 3-n At least one of the organoaluminum compounds, wherein Y is selected from hydrogen, C1-C20 hydrocarbon groups and C1-C20 hydroxyl groups, Z is selected from halogens, and n is an integer from 1 to 3.

[0112] In a preferred embodiment, Y is selected from C1-C20 alkyl, C1-C20 alkoxy, C7-C20 aralkyl, and C6-C20 aryl.

[0113] In a preferred embodiment, Z is selected from chlorine or bromine.

[0114] More preferably, the organoaluminum compound is selected from at least one of trimethylaluminum, triethylaluminum, triisobutylaluminum, tripropylaluminum, tributylaluminum, dimethylaluminum chloride, triisopropylaluminum, trisec-butylaluminum, tripentylaluminum, triisopentylaluminum, tricyclopentylaluminum, trihexylaluminum, trioctylaluminum, ethyldimethylaluminum, methyldiethylaluminum, triphenylaluminum, tri-p-methylphenylaluminum, dimethylmethoxyaluminum, methylaluminoxane (MAO), and modified methylaluminoxane (MMAO), with triisobutylaluminum being the most preferred.

[0115] In a preferred embodiment, the co-catalyst in the olefin polymerization catalyst is a combination of an organoboron compound and an organoaluminum compound. In this preferred embodiment, the organoboron compound is at least one selected from tris(pentafluorophenyl)borane, triphenylcarbamonite tetra(pentafluorophenyl)borate, and N,N-dimethylaniline tetra(pentafluorophenyl)borate, and the organoaluminum compound is triisobutylaluminum.

[0116] More preferably, the molar ratio Al / M of the aluminum in the co-catalyst to the metal M in the metal complex is 1-10000, more preferably 3-1000.

[0117] More preferably, the molar ratio B / M of the boron in the co-catalyst to the metal M in the metal complex is 0-10, preferably 0-4.

[0118] The present invention also provides an olefin polymerization method, which includes carrying out an olefin polymerization reaction in the presence of an olefin polymerization catalyst provided in the present invention.

[0119] In the olefin polymerization method of the present invention, the temperature of the olefin polymerization reaction can be -78°C to 200°C, more preferably -20°C to 150°C. Since the main catalyst used in the olefin polymerization catalyst is the fluorenyl-substituted tetrahydronaphthol-phosphine pre-transition metal complex of the present invention, the olefin polymerization method of the present invention is particularly suitable for olefin polymerization reactions at high temperatures. In some embodiments, the temperature of the olefin polymerization reaction is 80-140°C.

[0120] In the olefin polymerization method described in this invention, the polymerization pressure of the olefin polymerization reaction can be 0.01–10 MPa, preferably 0.01–5 MPa. In this invention, "polymerization pressure" refers to the ethylene pressure in the polymerization system, expressed as absolute pressure.

[0121] In the olefin polymerization method of the present invention, the polymerization reaction time of the olefin polymerization reaction can be 5 to 60 minutes.

[0122] In this invention, the olefin polymerization reaction can be homopolymerization or copolymerization.

[0123] In the olefin polymerization method described in this invention, the olefin can be a C2-C16 olefin.

[0124] In some embodiments, the olefin is ethylene.

[0125] In other embodiments, the olefin is a combination of ethylene and an α-olefin (such as 1-hexene, 1-octene, 4-methyl-1-pentene) or a cycloolefin (such as norbornene) having 3-16 carbon atoms.

[0126] In the olefin polymerization method of the present invention, the olefin polymerization reaction is carried out by olefin monomers in a solvent, and the polymerization solvent can be selected from one or more of alkanes, aromatic hydrocarbons, and halogenated hydrocarbons. As an example, the polymerization solvent is selected from one or more of hexane, pentane, heptane, decane, benzene, toluene, dichloromethane, chloroform, chlorobenzene, and dichloroethane, preferably one or more of hexane, toluene, heptane, and decane.

[0127] The metal complex described in this invention is used as the main catalyst for olefin polymerization. It has high homopolymerization / copolymerization activity, can catalyze olefin polymerization at higher temperatures, has better copolymerization performance with α-olefins (especially 1-octene), and the prepared olefin polymer has a significantly higher molecular weight. The resulting polymer has a narrow and tunable molecular weight distribution.

[0128] The following examples further illustrate the metal complexes, their preparation methods, and applications described in this invention. These examples are implemented based on the technical solutions of this invention, providing detailed implementation methods and specific operating procedures; however, the scope of protection of this invention is not limited to the following examples.

[0129] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods in the art. Unless otherwise specified, the experimental materials used in the following embodiments are commercially available.

[0130] The analytical characterization instruments and testing methods used in the following examples and comparative examples are as follows:

[0131] (1) Nuclear magnetic resonance spectrometer: AvanceⅢHD 500 (500MHz), with tetramethylsilicon (TMS) as internal standard.

[0132] (2) Molecular weight and molecular weight distribution of polymers (PDI = M) w / M n The determination was performed using a PL-GPC220 chromatograph with trichlorobenzene as solvent at 150℃ (standard: PS, flow rate: 1.0 mL / min, column: 3×PL gel 10um M1×ED-B, 300×7.5 nm).

[0133] (3) Activity measurement method: The polymer was washed with hydrochloric acid ethanol solution, vacuum dried, and the weight of the polymer was obtained. The polymerization activity was calculated as: polymer weight (g) / metal (mol) × 60 / polymerization time (min).

[0134] Example 1

[0135] Preparation of complex Hf1:

[0136] Complex Hf1: The complex shown in formula (I), wherein M is Hf, R1 is H, R2 is 2-isopropylphenyl, R3 is methyl, and n is 2.

[0137] Under a nitrogen atmosphere, 2.79 g (15 mmol) of 6-bromopyridine-2-carboxaldehyde, 2.58 g (15 mmol) of naphthaleneboronic acid, 22 mg of tetrakis(triphenylphosphine)palladium, and 9 g of potassium carbonate were added sequentially to a Schlenk flask, followed by 45 mL of ethanol, 30 mL of toluene, and 15 mL of deionized water. The mixture was stirred and refluxed overnight. After the reaction was complete, the mixture was extracted separately, washed with water, and dried to give 3.32 g of pyridine aldehyde compound A1, with a yield of 94%.

[0138] 2.33 g (10 mmol) of pyridinaldehyde compound A1, 2.07 g (10.5 mmol) of 9-aminofluorene, and 10 mg of p-toluenesulfonic acid were dissolved in 50 mL of toluene, and the mixture was refluxed with water separation for 48 h. After the reaction was completed, the solvent was evaporated and dried to give pyridinimine compound B1 in 92% yield.

[0139] 4.13 g (10 mmol) of pyridineimine compound B1 was dissolved in ultra-dry toluene, and 2-isopropylphenyllithium (12 mmol) solution was added dropwise at -78 °C. After refluxing overnight, the mixture was separated, dried, and recrystallized to give 4.53 g of white crystals with a yield of 85%, which was pyridineamine ligand L1. 1 H NMR (500MHz, CDCl3, TMS): δ8.08(d,1H),7.93(d,2H),7.67-7.60(m,9H),7.36-7.1 2(m,10H),5.59(s,1H),4.98(s,1H),3.38-3.31(m,1H),1.10(d,3H),0.98(d,3H).

[0140] Ligand L1 (0.96 g, 1.8 mmol) was weighed and dissolved in 10 mL of toluene. A solution of n-butyllithium (1.93 mL, 1.0 M) was added dropwise at 0 °C, and the reaction was allowed to proceed for 3 h. The toluene was dried under vacuum, and the solid was washed with n-hexane. The supernatant was discarded to obtain a yellow lithium salt. The lithium salt was redissolved in toluene, and HfCl4 (0.68 g, 2.0 mmol) was transferred into the reaction system. The mixture was heated to 90 °C and refluxed overnight. The solution temperature was then lowered to room temperature, and a solution of methyl magnesium bromide (MeMgBr, 7.14 mL, 3 mol / L) was added dropwise. The mixture was stirred at room temperature for 3 h. The solvent was dried under vacuum, and the solid was washed three times with n-hexane. The solid was filtered, and the hexane filtrate was collected. The solvent was concentrated to approximately 3 mL, and the solid was crystallized overnight at -35 °C. The crystals were filtered, washed with chilled n-hexane, and dried. Bright yellow crystals of Hf1 were obtained, with a yield of 82%. Elemental analysis was performed to determine C. 42 H 44HfN2(755.32): Theoretical values ​​are: C, 66.79; H, 5.87; N, 3.71; Test values ​​are: C, 66.42; H, 5.71; N, 3.58.

[0141] A 1L stainless steel polymerization reactor equipped with a mechanical stirrer was continuously dried at 130℃ for 6 hours, and then evacuated while hot and purged three times with N2 gas. 500 mL of n-heptane and 1.0 mmol of triisobutylaluminum (Hf:Al = 1:100) were injected into the polymerization reactor. 7.6 mg (10 μmol) of pyridineamine hafnium complex Hf1 and 12 μmol of triphenylcarbium tetra(pentafluorobenzene)borate (Hf:B = 1:1.2) were mixed and activated before being added to the reactor. The reaction was carried out at 60℃ with an ethylene pressure of 10 atm and vigorous stirring for 30 min. The mixture was neutralized with an ethanol solution acidified with 10 wt% hydrochloric acid to obtain polyethylene. The polymer was dried, weighed, and its polymerization activity was tested. The weight-average molecular weight, molecular weight distribution, and polymerization activity data of the obtained polymer are shown in Table 1.

[0142] Example 2

[0143] Complex Hf1: The complex shown in formula (I), wherein M is Hf, R1 is H, R2 is 2-isopropylphenyl, R3 is methyl, and n is 2.

[0144] A 1L stainless steel polymerization reactor equipped with a mechanical stirrer was continuously dried at 130℃ for 6 hours, and then evacuated while hot and purged three times with N2 gas. 500 mL of n-heptane and 1.0 mmol of triisobutylaluminum (Hf:Al = 1:100) were injected into the polymerization reactor. 7.6 mg (10 μmol) of pyridineamine hafnium complex Hf1 and 12 μmol of triphenylcarbium tetra(pentafluorobenzene)borate (Hf:B = 1:1.2) were mixed and activated before being added to the reactor. The reaction was carried out at 80℃ with an ethylene pressure of 10 atm and vigorous stirring for 30 min. The mixture was neutralized with an ethanol solution acidified with 10 wt% hydrochloric acid to obtain polyethylene. The polymer was dried, weighed, and its polymerization activity was tested. The weight-average molecular weight, molecular weight distribution, and polymerization activity data of the obtained polymer are shown in Table 1.

[0145] Example 3

[0146] Complex Hf1: The complex shown in formula (I), wherein M is Hf, R1 is H, R2 is 2-isopropylphenyl, R3 is methyl, and n is 2.

[0147] A 1L stainless steel polymerization reactor equipped with a mechanical stirrer was continuously dried at 130℃ for 6 hours, and then evacuated while hot and purged three times with N2 gas. 500 mL of n-heptane and 1.0 mmol of triisobutylaluminum (Hf:Al = 1:100) were injected into the reactor. 7.6 mg (10 μmol) of pyridineamine hafnium complex Hf1 was mixed with 12 μmol of triphenylcarbium tetra(pentafluorobenzene)borate (Hf:B = 1:1.2) and added to the reactor after activation. The reaction was carried out at 100℃ with an ethylene pressure of 10 atm and vigorous stirring for 30 min. The mixture was neutralized with an ethanol solution acidified with 10 wt% hydrochloric acid to obtain polyethylene. The polymer was dried, weighed, and its polymerization activity was tested. The weight-average molecular weight, molecular weight distribution, and polymerization activity data of the obtained polymer are shown in Table 1.

[0148] Example 4

[0149] Complex Hf1: The complex shown in formula (I), wherein M is Hf, R1 is H, R2 is 2-isopropylphenyl, R3 is methyl, and n is 2.

[0150] A 1L stainless steel polymerization reactor equipped with a mechanical stirrer was continuously dried at 130℃ for 6 hours, and then evacuated while hot and purged three times with N2 gas. 500 mL of n-heptane and 1.0 mmol of triisobutylaluminum (Hf:Al = 1:100) were injected into the polymerization reactor. 7.6 mg (10 μmol) of pyridineamine hafnium complex Hf1 was mixed with 11 μmol of triphenylcarbium tetra(pentafluorobenzene)borate (Hf:B = 1:1.1) and added to the reactor after activation. The reaction was carried out at 80℃ with an ethylene pressure of 10 atm and vigorous stirring for 30 min. The mixture was neutralized with an ethanol solution acidified with 10 wt% hydrochloric acid to obtain polyethylene. The polymer was dried, weighed, and its polymerization activity was tested. The weight-average molecular weight, molecular weight distribution, and polymerization activity data of the obtained polymer are shown in Table 1.

[0151] Example 5

[0152] Complex Hf1: The complex shown in formula (I), wherein M is Hf, R1 is H, R2 is 2-isopropylphenyl, R3 is methyl, and n is 2.

[0153] A 1L stainless steel polymerization reactor equipped with a mechanical stirrer was continuously dried at 130℃ for 6 hours, and then evacuated while hot and purged three times with N2 gas. 500 mL of n-heptane and 1.0 mmol of triisobutylaluminum (Hf:Al = 1:100) were injected into the polymerization reactor. 7.6 mg (10 μmol) of pyridineamine hafnium complex Hf1 was mixed with 13 μmol of triphenylcarbium tetra(pentafluorobenzene)borate (Hf:B = 1:1.3) and added to the reactor after activation. The reaction was carried out at 80℃ with an ethylene pressure of 10 atm and vigorous stirring for 30 min. The mixture was neutralized with an ethanol solution acidified with 10 wt% hydrochloric acid to obtain polyethylene. The polymer was dried, weighed, and its polymerization activity was tested. The weight-average molecular weight, molecular weight distribution, and polymerization activity data of the obtained polymer are shown in Table 1.

[0154] Example 6

[0155] Complex Hf1: The complex shown in formula (I), wherein M is Hf, R1 is H, R2 is 2-isopropylphenyl, R3 is methyl, and n is 2.

[0156] A 1L stainless steel polymerization reactor equipped with a mechanical stirrer was continuously dried at 130℃ for 6 hours, and then evacuated while hot and purged three times with N2 gas. 500 mL of n-heptane and 2.0 mmol of triisobutylaluminum (Hf:Al = 1:200) were injected into the polymerization reactor. 7.6 mg (10 μmol) of pyridineamine hafnium complex Hf1 and 12 μmol of triphenylcarbium tetra(pentafluorobenzene)borate (Hf:B = 1:1.2) were mixed and activated before being added to the reactor. The reaction was carried out at 80℃ with an ethylene pressure of 10 atm and vigorous stirring for 30 min. The mixture was neutralized with an ethanol solution acidified with 10 wt% hydrochloric acid to obtain polyethylene. The polymer was dried, weighed, and its polymerization activity was tested. The weight-average molecular weight, molecular weight distribution, and polymerization activity data of the obtained polymer are shown in Table 1.

[0157] Example 7

[0158] Complex Hf1: The complex shown in formula (I), wherein M is Hf, R1 is H, R2 is 2-isopropylphenyl, R3 is methyl, and n is 2.

[0159] A 1L stainless steel polymerization reactor equipped with a mechanical stirrer was continuously dried at 130℃ for 6 hours, and then evacuated while hot and purged three times with N2 gas. 500 mL of n-heptane and 5.0 mmol of triisobutylaluminum (Hf:Al = 1:500) were injected into the polymerization reactor. 7.6 mg (10 μmol) of pyridineamine hafnium complex Hf1 and 12 μmol of triphenylcarbium tetra(pentafluorobenzene)borate (Hf:B = 1:1.2) were mixed and activated before being added to the reactor. The reaction was carried out at 80℃ with an ethylene pressure of 10 atm and vigorous stirring for 30 min. The mixture was neutralized with an ethanol solution acidified with 10 wt% hydrochloric acid to obtain polyethylene. The polymer was dried, weighed, and its polymerization activity was tested. The weight-average molecular weight, molecular weight distribution, and polymerization activity data of the obtained polymer are shown in Table 1.

[0160] Example 8

[0161] Complex Hf1: The complex shown in formula (I), wherein M is Hf, R1 is H, R2 is 2-isopropylphenyl, R3 is methyl, and n is 2.

[0162] A 1L stainless steel polymerization reactor equipped with a mechanical stirrer was continuously dried at 130℃ for 6 hours, and then evacuated while hot and purged three times with N2 gas. 500 mL of decane, 1.0 mmol of triisobutylaluminum (Hf:Al = 1:100), and 20 mL of 1-hexene were injected into the reactor. 7.6 mg (10 μmol) of the pyridine-amino hafnium complex Hf1 was mixed with 12 μmol of triphenylcarbium tetra(pentafluorobenzene)borate (Hf:B = 1:1.2) and activated before being added to the reactor. The reaction was carried out at 120℃ with a 10 atm ethylene pressure and vigorous stirring for 30 min. The mixture was neutralized with an ethanol solution acidified with 10 wt% hydrochloric acid to obtain the polymer. The polymer was dried, weighed, and its polymerization activity was tested. The weight-average molecular weight, molecular weight distribution, and polymerization activity data of the obtained polymer are shown in Table 1.

[0163] Example 9

[0164] Complex Hf1: The complex shown in formula (I), wherein M is Hf, R1 is H, R2 is 2-isopropylphenyl, R3 is methyl, and n is 2.

[0165] A 1L stainless steel polymerization reactor equipped with a mechanical stirrer was continuously dried at 130℃ for 6 hours, and then evacuated while hot and purged three times with N2 gas. 500 mL of decane, 1.0 mmol of triisobutylaluminum (Hf:Al = 1:100), and 100 mL of 1-octene were injected into the reactor. 7.6 mg (10 μmol) of the pyridine-amino hafnium complex Hf1 was mixed with 12 μmol of triphenylcarbium tetra(pentafluorobenzene)borate (Hf:B = 1:1.2) and added to the reactor after activation. The reaction was carried out at 140℃ with a 10 atm ethylene pressure and vigorous stirring for 30 min. The mixture was neutralized with an ethanol solution acidified with 10 wt% hydrochloric acid to obtain the polymer. The polymer was dried, weighed, and its polymerization activity was tested. The weight-average molecular weight, molecular weight distribution, and polymerization activity data of the obtained polymer are shown in Table 1.

[0166] Example 10

[0167] Complex Hf1: The complex shown in formula (I), wherein M is Hf, R1 is H, R2 is 2-isopropylphenyl, R3 is methyl, and n is 2.

[0168] A 1L stainless steel polymerization reactor equipped with a mechanical stirrer was continuously dried at 130℃ for 6 hours, and then evacuated while hot and purged three times with N2 gas. 500 mL of n-heptane, 1.0 mmol of triisobutylaluminum (Hf:Al = 1:100), and 10 mL of 4-methyl-1-pentene were injected into the reactor. 7.6 mg (10 μmol) of pyridineamine hafnium complex Hf1 was mixed with 12 μmol of triphenylcarbium tetra(pentafluorobenzene)borate (Hf:B = 1:1.2) for activation and then added to the reactor. The reaction was carried out at 80℃ with an ethylene pressure of 10 atm and vigorous stirring for 30 min. The mixture was neutralized with an ethanol solution acidified with 10 wt% hydrochloric acid to obtain the polymer. The polymer was dried, weighed, and its polymerization activity was tested. The weight-average molecular weight, molecular weight distribution, and polymerization activity data of the obtained polymer are shown in Table 1.

[0169] Example 11

[0170] Preparation of complex Hf2

[0171] Complex Hf2: The complex shown in formula (I), wherein M is Hf, R1 is H, R2 is 2-cyclohexylphenyl, R3 is methyl, and n is 2.

[0172] Under a nitrogen atmosphere, 2.79 g (15 mmol) of 6-bromopyridine-2-carboxaldehyde, 2.58 g (15 mmol) of naphthaleneboronic acid, 22 mg of tetrakis(triphenylphosphine)palladium, and 9 g of potassium carbonate were added sequentially to a Schlenk flask. Then, 45 mL of ethanol, 30 mL of toluene, and 15 mL of deionized water were added, and the mixture was stirred and refluxed overnight. After the reaction was complete, the mixture was extracted separately, washed with water, and dried to obtain 3.32 g of pyridine aldehyde compound A1, with a yield of 94%.

[0173] 2.33 g (10 mmol) of pyridinaldehyde compound A1, 2.07 g (10.5 mmol) of 9-aminofluorene, and 10 mg of p-toluenesulfonic acid were dissolved in 50 mL of toluene, and the mixture was refluxed with water separation for 48 h. After the reaction was completed, the solvent was evaporated and dried to give pyridinimine compound B1 in 92% yield.

[0174] 4.13 g (10 mmol) of pyridineimine compound B1 was dissolved in ultra-dry toluene, and 2-cyclohexylphenyllithium (12 mmol) solution was added dropwise at -78 °C. After refluxing overnight, the mixture was separated, dried, and recrystallized to give 4.70 g of white crystals with a yield of 82%, which was pyridineamine ligand L2. 1 H NMR (500MHz, CDCl3, TMS): δ8.17(d,1H),8.01(d,2H),7.76-7.60(m,9H),7.47-7.35(m,1 0H),5.38(s,1H),5.00(s,1H),2.78-2.67(m,1H),1.86-1.61(m,4H),1.53-1.44(m,6H).

[0175] Ligand L2 (1.03 g, 1.8 mmol) was weighed and dissolved in 10 mL of toluene. A solution of n-butyllithium (1.93 mL, 1.0 M) was added dropwise at 0 °C, and the reaction was allowed to proceed for 3 h. The toluene was dried under vacuum, and the solid was washed with n-hexane. The supernatant was discarded to obtain a yellow lithium salt. The lithium salt was redissolved in toluene, and HfCl4 (0.68 g, 2.0 mmol) was transferred into the reaction system. The mixture was heated to 90 °C and refluxed overnight. The solution temperature was then lowered to room temperature, and a solution of methyl magnesium bromide (MeMgBr, 7.14 mL, 3 mol / L) was added dropwise. The mixture was stirred at room temperature for 3 h. The solvent was dried under vacuum, and the solid was washed three times with n-hexane. The solid was filtered, and the hexane filtrate was collected. The solvent was concentrated to approximately 3 mL, and the solid was crystallized overnight at -35 °C. The crystals were filtered, washed with chilled n-hexane, and dried. Bright yellow crystals of Hf2 were obtained, with a yield of 84%. Elemental analysis was performed to determine C. 45 H 48 HfN2(795.38): Theoretical values ​​are: C, 67.95; H, 6.08; N, 3.52; Test values ​​are: C, 68.01; H, 5.71; N, 3.33.

[0176] A 1L stainless steel polymerization reactor equipped with a mechanical stirrer was continuously dried at 130℃ for 6 hours, and then evacuated while hot and purged three times with N2 gas. 500 mL of n-heptane and 1.0 mmol of triisobutylaluminum (Hf:Al = 1:100) were injected into the polymerization reactor. 8.0 mg (10 μmol) of pyridineamine hafnium complex Hf2 and 12 μmol of triphenylcarbium tetra(pentafluorobenzene)borate (Hf:B = 1:1.2) were mixed and activated before being added to the reactor. The reaction was carried out at 80℃ with an ethylene pressure of 10 atm and vigorous stirring for 30 min. The mixture was neutralized with an ethanol solution acidified with 10 wt% hydrochloric acid to obtain polyethylene. The polymer was dried, weighed, and its polymerization activity was tested. The weight-average molecular weight, molecular weight distribution, and polymerization activity data of the obtained polymer are shown in Table 1.

[0177] Example 12

[0178] Complex Hf2: The complex shown in formula (I), wherein M is Hf, R1 is H, R2 is 2-cyclohexylphenyl, R3 is methyl, and n is 2.

[0179] A 1L stainless steel polymerization reactor equipped with a mechanical stirrer was continuously dried at 130℃ for 6 hours, and then evacuated while hot and purged three times with N2 gas. 500 mL of decane, 1.0 mmol of triisobutylaluminum (Hf:Al = 1:100), and 100 mL of 1-octene were injected into the reactor. 8.0 mg (10 μmol) of pyridineamine hafnium complex Hf2 and 12 μmol of triphenylcarbium tetra(pentafluorobenzene)borate (Hf:B = 1:1.2) were mixed and activated before being added to the reactor. The reaction was carried out at 140℃ with a 10 atm ethylene pressure and vigorous stirring for 30 min. The mixture was neutralized with an ethanol solution acidified with 10 wt% hydrochloric acid to obtain the polymer. The polymer was dried, weighed, and its polymerization activity was tested. The weight-average molecular weight, molecular weight distribution, and polymerization activity data of the obtained polymer are shown in Table 1.

[0180] Example 13

[0181] Preparation of complex Hf3

[0182] Complex Hf3: The complex shown in formula (I), wherein M is Hf, R1 is H, R2 is 2-cyclohexylphenyl, R3 is benzyl, and n is 2.

[0183] Ligand L2 was prepared according to the method in Example 11.

[0184] Ligand L2 (1.03 g, 1.8 mmol) was weighed and dissolved in 10 mL of toluene. A solution of n-butyllithium (1.93 mL, 1.0 M) was added dropwise at 0 °C, and the reaction was allowed to proceed for 3 h. The toluene was dried under vacuum, and the solid was washed with n-hexane. The supernatant was discarded to obtain a yellow lithium salt. The lithium salt was redissolved in toluene, and HfCl4 (0.68 g, 2.0 mmol) was transferred into the reaction system. The mixture was heated to 90 °C and refluxed overnight. The solution temperature was then lowered to room temperature, and a solution of benzyl magnesium bromide (MeMgBr, 7.14 mL, 3 mol / L) was added dropwise. The mixture was stirred at room temperature for 3 h. The solvent was dried under vacuum, and the solid was washed three times with n-hexane. The solid was filtered and the hexane filtrate was collected. The solvent was concentrated to approximately 3 mL, and the solid was crystallized overnight at -35 °C. The crystals were filtered, washed with frozen n-hexane, and dried. Bright yellow crystals Hf3 were obtained in 82% yield. Elemental analysis was performed to determine C. 57 H 56 HfN2 (947.58): Theoretical values ​​are: C, 72.25; H, 5.96; N, 2.96; Test values ​​are: C, 72.01; H, 5.67; N, 3.12.

[0185] A 1L stainless steel polymerization reactor equipped with a mechanical stirrer was continuously dried at 130℃ for 6 hours, and then evacuated while hot and purged three times with N2 gas. 500 mL of n-heptane and 1.0 mmol of triisobutylaluminum (Hf:Al = 1:100) were injected into the polymerization reactor. 9.5 mg (10 μmol) of pyridineamine hafnium complex Hf3 and 12 μmol of triphenylcarbium tetra(pentafluorobenzene)borate (Hf:B = 1:1.2) were mixed and activated before being added to the reactor. The reaction was carried out at 80℃ with an ethylene pressure of 10 atm and vigorous stirring for 30 min. The mixture was neutralized with an ethanol solution acidified with 10 wt% hydrochloric acid to obtain polyethylene. The polymer was dried, weighed, and its polymerization activity was tested. The weight-average molecular weight, molecular weight distribution, and polymerization activity data of the obtained polymer are shown in Table 1.

[0186] Example 14

[0187] Complex Hf3: The complex shown in formula (I), wherein M is Hf, R1 is H, R2 is 2-cyclohexylphenyl, R3 is benzyl, and n is 2.

[0188] A 1L stainless steel polymerization reactor equipped with a mechanical stirrer was continuously dried at 130℃ for 6 hours, and then evacuated while hot and purged three times with N2 gas. 500 mL of decane, 1.0 mmol of triisobutylaluminum (Hf:Al = 1:100), and 100 mL of 1-octene were injected into the reactor. 9.5 mg (10 μmol) of pyridineamine hafnium complex Hf3 and 12 μmol of triphenylcarbium tetra(pentafluorobenzene)borate (Hf:B = 1:1.2) were mixed and activated before being added to the reactor. The reaction was carried out at 140℃ with a 10 atm ethylene pressure and vigorous stirring for 30 min. The mixture was neutralized with an ethanol solution acidified with 10 wt% hydrochloric acid to obtain the polymer. The polymer was dried, weighed, and its polymerization activity was tested. The weight-average molecular weight, molecular weight distribution, and polymerization activity data of the obtained polymer are shown in Table 1.

[0189] Example 15

[0190] Preparation of complex Zr1

[0191] Complex Zr1: The complex shown in formula (I), wherein M is Zr, R1 is H, R2 is 2-isopropylphenyl, R3 is methyl, and n is 2.

[0192] Ligand L1 was prepared according to the method in Example 1.

[0193] Ligand L1 (0.96 g, 1.8 mmol) was weighed and dissolved in 10 mL of toluene. A solution of n-butyllithium (1.93 mL, 1.0 M) was added dropwise at 0 °C, and the reaction was allowed to proceed for 3 h. The toluene was dried under vacuum, and the solid was washed with n-hexane. The supernatant was discarded to obtain a yellow lithium salt. The lithium salt was redissolved in toluene, and ZrCl4 (0.47 g, 2.0 mmol) was transferred into the reaction system. The mixture was heated to 90 °C and refluxed overnight. The solution temperature was then lowered to room temperature, and a solution of methyl magnesium bromide (MeMgBr, 7.14 mL, 3 mol / L) was added dropwise. The mixture was stirred at room temperature for 3 h. The solvent was dried under vacuum, and the solid was washed three times with n-hexane. The solid was filtered, and the hexane filtrate was collected. The solvent was concentrated to approximately 3 mL, and the solid was crystallized overnight at -35 °C. The crystals were filtered, washed with frozen n-hexane, and dried. Bright yellow crystals of Zr1 were obtained, with a yield of 85%. Elemental analysis was performed to determine C. 42 H 44 ZrN2 (668.05): Theoretical values ​​are: C, 75.51; H, 6.64; N, 4.19; Test values ​​are: C, 75.33; H, 6.34; N, 4.43.

[0194] A 1L stainless steel polymerization reactor equipped with a mechanical stirrer was continuously dried at 130℃ for 6 hours, and then evacuated while hot and purged three times with N2 gas. 500 mL of decane and 1.0 mmol of triisobutylaluminum (Hf:Al = 1:100) were injected into the polymerization reactor. 6.7 mg (10 μmol) of pyridineamine hafnium complex Zr1 was mixed with 12 μmol of triphenylcarbium tetra(pentafluorobenzene)borate (Zr:B = 1:1.2) and added to the reactor after activation. The reaction was carried out at 100℃ with a 10 atm ethylene pressure and vigorous stirring for 30 min. The mixture was neutralized with an ethanol solution acidified with 10 wt% hydrochloric acid to obtain polyethylene. The polymer was dried, weighed, and its polymerization activity was tested. The weight-average molecular weight, molecular weight distribution, and polymerization activity data of the obtained polymer are shown in Table 1.

[0195] Comparative Example 1

[0196] A 1L stainless steel polymerization reactor equipped with a mechanical stirrer was continuously dried at 130℃ for 6 hours, and then evacuated while hot and purged three times with N2 gas. 500 mL of n-heptane and 1.0 mmol of triisobutylaluminum (Hf:Al = 1:100) were injected into the polymerization reactor. 7.4 mg (10 μmol) of pyridineamine hafnium complex A (synthesis reference: patent application US2004220050A1) was mixed with 12 μmol of triphenylcarbium tetra(pentafluorobenzene)borate (Hf:B = 1:1.2) and activated before being added to the reactor. The reaction was carried out at 100℃ with an ethylene pressure of 10 atm and vigorous stirring for 30 min. The mixture was neutralized with an ethanol solution acidified with 10 wt% hydrochloric acid to obtain polyethylene. The polymer was dried, weighed, and its polymerization activity was tested. The weight-average molecular weight, molecular weight distribution, and polymerization activity data of the obtained polymer are shown in Table 1.

[0197]

[0198] Comparative Example 2

[0199] A 1L stainless steel polymerization reactor equipped with a mechanical stirrer was continuously dried at 130℃ for 6 hours, and then evacuated while hot and purged three times with N2 gas. 500 mL of decane, 1.0 mmol of triisobutylaluminum (Hf:Al = 1:100), and 100 mL of 1-octene were injected into the reactor. 7.4 mg (10 μmol) of pyridineamine hafnium complex A and 12 μmol of triphenylcarbium tetra(pentafluorobenzene)borate (Hf:B = 1:1.2) were mixed and activated before being added to the reactor. The reaction was carried out at 140℃ with a 10 atm ethylene pressure and vigorous stirring for 30 min. The mixture was neutralized with an ethanol solution acidified with 10 wt% hydrochloric acid to obtain polyethylene. The polymer was dried, weighed, and its polymerization activity was tested. The weight-average molecular weight, molecular weight distribution, and polymerization activity data of the obtained polymer are shown in Table 1.

[0200] Table 1

[0201]

[0202]

[0203] As can be seen from the data in Table 1, compared with Examples 1-7, 11, 13, and 15, Comparative Example 1, using the metal complex of the present invention as a homopolymerization catalyst for ethylene, exhibits higher olefin polymerization activity and superior high-temperature resistance under similar polymerization conditions, resulting in a significantly higher molecular weight and narrower molecular weight distribution of the obtained polymer. Compared with Examples 8-10, 12, and 14, Comparative Example 2 shows higher activity in the copolymerization of ethylene and α-olefins (especially 1-octene) using the metal complex of the present invention, resulting in a significantly higher molecular weight and narrower molecular weight distribution of the obtained polymer. The metal complex of the present invention contains a sterically hindered fluorene group, and its catalytic activity when used as a catalyst is consistently above 10. 6 g polymer / (mol cat The above (·h) demonstrates the characteristics of a single active center.

[0204] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A metal complex, characterized in that, Its structural formula is shown in equation (I). Among them, R 1 With R 2 Same or different, and R 1 and R 2 Each is independently selected from hydrogen and C1-C30 hydrocarbon groups; n is 1 or 2. When n is 2, R 3 It is a halogen or a monovalent substituent having 1-20 atoms other than hydrogen; when n is 1, R 3 It is a divalent substituent having 1-40 atoms other than hydrogen; M is selected from group IVB metals.

2. The metal complex according to claim 1, characterized in that, R 1 and R 2 Each is independently selected from hydrogen, C1-C20 alkyl or cycloalkyl, C2-C6 olefin, C1-C20 alkoxy, C3-20 cycloalkyloxy, C6-30 aryl or substituted aryl and C6-30 aryloxy.

3. The metal complex according to claim 1 or 2, characterized in that, R 1 and R 2 One of them is hydrogen.

4. The metal complex according to claim 1, characterized in that, When n is 2, the two R 3 Each is independently selected from halogens, alkyl groups, substituted alkyl groups, aryl groups, and substituted aryl groups; When n is 1, R 3 It is 1,3-butadiene or 1,3-pentadiene directly coordinated with metal M or formed a covalent bond.

5. The metal complex according to claim 1 or 4, characterized in that, M represents titanium, zirconium, or hafnium.

6. The metal complex according to any one of claims 1-5, characterized in that, It is selected from the group consisting of the following coordination compounds: Complex 1: The complex shown in formula (I), where M is Hf and R is... 1 For H, R 2 It is 2-isopropylphenyl, R 3 It is a methyl group, and n is 2; Complex 2: The complex shown in formula (I), where M is Hf and R is... 1 For H, R 2 It is 2-cyclohexylphenyl, R 3 It is a methyl group, and n is 2; Complex 3: The complex shown in formula (I), where M is Hf and R is... 1 For H, R 2 It is isopropyl, R 3 It is a methyl group, and n is 2; Complex 4: The complex shown in formula (I), where M is Hf and R is... 1 For H, R 2 It is a phenyl group, R 3 It is a methyl group, and n is 2; Complex 5: The complex shown in formula (I), where M is Hf and R is... 1 For H, R 2 It is 2-methylphenyl, R 3 It is a methyl group, and n is 2; Complex 6: The complex shown in formula (I), where M is Hf and R is... 1 For H, R 2 It is 2-cyclohexylphenyl, R 3 It is benzyl, and n is 2; Complex 7: The complex shown in formula (I), where M is Hf and R is... 1 For H, R 2 It is naphthyl, R 3 It is benzyl, and n is 2; Complex 8: The complex shown in formula (I), where M is Hf and R is... 1 For H, R 2 It is 2,4-dimethoxyphenyl, R 3 It is benzyl, and n is 2; Complex 9: The complex shown in formula (I), where M is Zr and R is R. 1 For H, R 2 It is 2-isopropylphenyl, R 3 It is a methyl group, and n is 2.

7. A method for preparing the metal complex according to any one of claims 1-6, characterized in that, The method includes the following steps: (1) In an organic solvent, the pyridinaldehyde compound of formula (II) is coupled with naphthaleneboronic acid to obtain the 2-naphthyl-pyridinaldehyde compound of formula (IⅡ); (2) In an organic solvent, the 2-naphthyl-pyridinaldehyde compound is condensed with 9-aminofluorene to obtain the pyridinimine compound shown in formula (IV); (3) In an organic solvent, the pyridineimine compound is reacted with a reducing agent (R) 2 ) m M1 undergoes a reduction reaction to yield the pyridine amino compound ligand shown in formula (V); (4) In an organic solvent, the pyridine amino compound ligand is first reacted with a dehydrogenating agent to generate a salt, and then complexed with the metal salt of M. Among them, R 1 Selected from hydrogen and C1-C30 hydrocarbon groups; R 2 It is a C1-C30 hydrocarbon group; X is a halogen; M is selected from group IVB metals; M1 is Li, Al or Na; m is an integer from 1 to 3.

8. The method according to claim 7, characterized in that, In formula (II), X is bromine.

9. The method according to claim 7, characterized in that, In step (3), the reducing agent is trialkylaluminum and / or aryllithium.

10. The method according to claim 7, characterized in that, In step (4), the dehydrogenating agent is one or more of sodium hydride, potassium hydride, lithium hydride, tetramethylethylenediamine, bis(trimethylsilylamino) lithium, bis(trimethylsilylamino) sodium, diisopropylamino lithium and C1-C6 alkyl lithium.

11. The method according to claim 7, characterized in that, In step (4), the metal salt of M is at least one of a halide of metal M and an alkyl compound of metal M.

12. The method according to claim 7, characterized in that, In steps (1) to (4), the organic solvents used are each independently selected from one or more of tetrahydrofuran, anhydrous diethyl ether, pentane, cyclopentane, n-hexane, cyclohexane, heptane, methylcyclohexane, toluene, xylene, chlorobenzene and o-dichlorobenzene.

13. The method according to claim 7, characterized in that, In step (4), the molar ratio of the pyridine amino compound ligand shown in formula (V) to the dehydrogenating agent is 1:(0.8-2), preferably 1:(1-1.5); and / or The reaction conditions for salt formation include: a temperature of -78°C to 35°C, preferably -78°C to 0°C; a time of 1-24 hours; and / or The molar ratio of the pyridine amino compound ligand shown in formula (V) to the metal salt of M, based on metal ions, is 1:(1-2), preferably 1:(1.05-1.5); and / or The conditions for the complexation reaction include: a temperature of 60°C to 120°C and a time of 4-30 hours.

14. An olefin polymerization catalyst, comprising a main catalyst and a co-catalyst, characterized in that, The main catalyst is a metal complex as described in any one of claims 1-6.

15. The olefin polymerization catalyst according to claim 14, characterized in that, The cocatalyst is an organoaluminum compound, or a combination of an organoaluminum compound and an organoboronide.

16. The olefin polymerization catalyst according to claim 15, characterized in that, The organoboron compounds are selected from triethylammonium tetra(phenyl)boron, tributylammonium tetra(phenyl)boron, trimethylammonium tetra(phenyl)boron, tripropylammonium (phenyl)boron, trimethylammonium tetra(p-methylphenyl)boron, trimethylammonium tetra(o,p-dimethylphenyl)boron, tributylammonium tetra(p-trifluoromethylphenyl)boron, trimethylammonium tetra(p-trifluoromethylphenyl)boron, tributylammonium tetra(pentafluorophenyl)boron, N,N-diethylaniline tetra(phenyl)boron, N,N-diethylaniline tetra(pentafluorophenyl)boron, diethylaniline tetra(pentafluorophenyl)boron, trimethylphosphine tetra(phenyl)boron, tripropylammonium tetra(p-tolyl)boron, At least one of the following: triethylammonium tetra(p-trifluoromethylphenyl)boron, triethylammonium tetra(o,p-dimethylphenyl)boron, trimethylammonium tetra(o,p-dimethylphenyl)boron, tributylammonium tetra(p-trifluoromethylphenyl)boron, trimethylammonium tetra(p-trifluoromethylphenyl)boron, tributylammonium tetra(pentafluorophenyl)boron, triphenylphosphine tetra(phenyl)boron, tri(pentafluorophenyl)borane, triphenylcarbium tetra(pentafluorophenyl)boron, triphenylcarbium tetra(p-trifluoromethylphenyl)boron, N,N-dimethylaniline tetra(pentafluorophenyl)boron, triphenylcarbium tetra(pentafluorophenyl)borate, and N,N-dimethylaniline tetra(pentafluorophenyl)borate.

17. The olefin polymerization catalyst according to claim 15, characterized in that, The organoaluminum compound is at least one of trimethylaluminum, triethylaluminum, triisobutylaluminum, tripropylaluminum, tributylaluminum, dimethylaluminum chloride, triisopropylaluminum, trisec-butylaluminum, tripentylaluminum, triisopentylaluminum, tricyclopentylaluminum, trihexylaluminum, trioctylaluminum, ethyldimethylaluminum, methyldiethylaluminum, triphenylaluminum, tri-p-methylphenylaluminum, dimethylmethoxyaluminum, methylaluminoxane, and modified methylaluminoxane.

18. The olefin polymerization catalyst according to any one of claims 15-17, characterized in that, The molar ratio Al / M of aluminum in the co-catalyst to metal M in the metal complex is 1-10000, and the molar ratio B / M of boron in the co-catalyst to metal M in the metal complex is 0-10.

19. A method for olefin polymerization, characterized in that, The method includes: carrying out an olefin polymerization reaction in the presence of an olefin polymerization catalyst according to any one of claims 14-18.

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