Metallocene complex with double active centers as well as preparation method and application of metallocene complex

Abstract

The invention provides a double-active-center metallocene complex as well as a preparation method and application thereof. The complex provided by the invention can effectively exert the synergistic catalytic effect of double active centers, has extremely high catalytic activity when being used for catalyzing copolymerization of ethylene and / or alpha-olefin and cycloolefin, and also has good high-temperature resistance, and the prepared polymerization product is relatively wide in molecular weight distribution, convenient and adjustable, and is suitable for industrial production. The bimodal COC polymer can be prepared by a single catalyst, and the polymer has excellent toughness while maintaining high heat resistance and mechanical strength. Therefore, the complex provided by the invention is very suitable for catalyzing the copolymerization reaction of ethylene and / or alpha-olefin and cycloolefin.

Description

Technical Field

[0001] The present invention relates to the field of olefin polymerization, and particularly relates to a biphenyl-bridged bis-active center metallocene complex, a preparation method and a use thereof, and also relates to an olefin polymerization method. Background Art

[0002] Metallocene catalysts are a class of organometallic coordination compounds formed by transition metals (usually Group IVB elements such as Ti, Zr, Hf, etc.) and cyclopentadiene or its derivatives, and can be used to catalyze the homopolymerization and copolymerization of various olefins to prepare polymers such as polyethylene, polypropylene, and polyolefin elastomers.

[0003] When a single-active center metallocene catalyst catalyzes a polymerization reaction, its product usually has a relatively narrow molecular weight distribution and a very low extractable content. By changing the structure of the active center metal or ligand, its catalytic activity, stereoregularity of the polymerization product, etc. can be adjusted. Compared with the heterogeneous Ziegler-Natta catalyst, the emergence of the single-active center metallocene catalyst makes up for its deficiency in the diversity of polymer structures. Its high-activity catalyzes the copolymerization of ethylene with α-olefins, diolefins, cycloolefins, and even polar monomers, and more types of new polyolefin products can be obtained to meet the increasingly diversified application requirements.

[0004] Although the single-active center metallocene catalyst has the above-mentioned excellent catalytic properties, however, the too narrow molecular weight distribution of its polymer will reduce the processing performance of the polymer resin. To solve this problem, it can be achieved by adjusting the molecular weight distribution, such as preparing polyolefins with a bimodal distribution. For example, Chinese patents CN114736321A, CN114853947A, and CN105524217A respectively provide methods for preparing polymers with different molecular weight distributions.

[0005] The commonly used methods for preparing polyolefins with a bimodal or multimodal molecular weight distribution mainly include the following three: one is the physical blending of polymers with different molecular weights. CN101838365A prepared a bimodal distribution ethylene-α-olefin-non-conjugated diene copolymer elastomer through a parallel reaction kettle, but this method has a high cost and it is difficult to ensure the product uniformity, which affects the performance; the second is the staged polymerization in a multi-stage reactor. EP1472295B1 prepared a bimodal distribution elastomer by controlling the polymerization conditions of two reactors, but this method is complex in operation and low in efficiency. The third is to prepare polyolefins with a bimodal distribution in a single reactor by using a dual / multi-metal or composite catalyst, etc. However, the existing dual / multi-metal catalysts have low activity and complex synthesis (CN115246893A, CN110386957B), and the composite catalyst requires two or more different types of catalysts, and it is difficult to control the catalytic activity and polymer performance (CN114736321A, CN105524217B). Summary of the Invention

[0006] The present invention provides a metallocene complex with dual active centers. By reasonably designing the bridging group and the metallocene catalyst structure, the two active centers have appropriate spacing, coordination space and electron distribution, and can effectively exert the synergistic catalytic effect of the dual active centers, so as to obtain an excellent catalyst with high catalytic activity, simple regulation of polymer molecular weight and distribution, and high temperature resistance. At the same time, the catalyst synthesis process is simple and convenient for industrial application. As a catalyst, this complex is used to catalyze the polymerization of ethylene and / or α-olefin with cycloolefin to prepare polyolefin with bimodal or multimodal distribution, and can obtain COC with both mechanical strength and toughness, which is convenient for processing, and the catalyst has good high temperature stability.

[0007] Another object of the present invention is to provide a preparation method of the metallocene complex with dual active centers.

[0008] Still another object of the present invention is to provide a method for olefin polymerization.

[0009] The first aspect of the present invention provides a biphenyl-bridged metallocene complex with dual active centers having a structure shown in formula (I),

[0010]

[0011] wherein, M is selected from titanium, zirconium or hafnium;

[0012] Cp 1 , Cp 2 and Cp 3 are each independently selected from a substituted or unsubstituted cyclopentadienyl, indenyl or fluorenyl;

[0013] A is selected from a carbon atom or a silicon atom;

[0014] R 1 and R 2 are each independently selected from hydrogen, a substituted or unsubstituted C1-C20 alkyl group, a C3-C20 cycloalkyl group, a C6-C20 aryl group or a silyl group containing 1-3 Si atoms;

[0015] X is selected from a halogen, -NH 2 , a substituted or unsubstituted C1-C20 alkyl group, -N(C1-C20 alkyl) 2 , a C6-C20 aryl group or a benzyl group;

[0016] When the above groups are substituted groups, the number of substituents is 1, 2, 3 or 4, and are each independently selected from a halogen, a C1-C10 alkyl group, a C1-C10 alkoxy group, a C3-C10 cycloalkyl group, a C6-C20 aryl group or a benzyl group.

[0017] Preferably, in the dual-active-site metallocene complex provided by the present invention, the R 1 and R 2 each independently selected from hydrogen, C1-C6 alkyl, C3-C8 cycloalkyl or C6-C12 aryl. In some preferred embodiments, the R 1 and R 2 each independently selected from hydrogen, C1-C4 alkyl, C3-C6 cycloalkyl or C6-C12 aryl, including but not limited to hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, phenyl, etc.

[0018] Preferably, in the dual-active-site metallocene complex provided by the present invention, the X is selected from halogen, C1-C4 alkyl or -NH 2 . In some preferred embodiments, the X is selected from halogen, including F, Cl, Br and I. In some more preferred embodiments, the X is selected from Cl.

[0019] Preferably, in the dual-active-site metallocene complex provided by the present invention, the Cp 1 and Cp 2 are selected from substituted or unsubstituted indenyl or fluorenyl, and the Cp 3 is selected from substituted or unsubstituted cyclopentadienyl. In some preferred embodiments, the Cp 1 and Cp 2 are selected from indenyl or fluorenyl, and the Cp 3 is selected from cyclopentadienyl.

[0020] Preferably, when the Cp 1 and / or Cp 2 and / or Cp 3 is a substituted group, the number of substituents is 1 or 2, each independently selected from halogen, C1-C6 alkyl, C1-C6 alkoxy, C3-C8 cycloalkyl, C6-C12 aryl or benzyl. In some preferred embodiments, the substituents are selected from C1-C4 alkyl (including but not limited to methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, etc.), C3-C6 cycloalkyl, phenyl, naphthyl, biphenyl, benzyl, etc.

[0021] The dual-active-site metallocene complex provided by the present invention is further preferably selected from any one of the following complexes Cat.1-Cat.6:

[0022]

[0023]

[0024] The second aspect of the present invention provides a preparation method of the biphenyl-bridged dual-active-site metallocene complex, comprising the following steps:

[0025] S1: Dissolve 2-bromo-2'-iodobiphenyl in a solvent, then add alkyllithium for lithiation at low temperature, followed by the addition of trimethyl borate for reaction, and then add an aqueous hydrochloric acid solution for hydrolysis to obtain compound 2'-bromo-1,1'-biphenyl-2-boronic acid (denoted as compound A);

[0026] S2: React compound A with a halogenated product of Cp 1 through a Suzuki coupling reaction catalyzed by a palladium catalyst under basic conditions to obtain compound B;

[0027] S3: React compound B with boric acid or a Cp 2 substituted with a borate group through a Suzuki coupling reaction catalyzed by a palladium catalyst under basic conditions to obtain intermediate II;

[0028] S4: React the intermediate II with an organometallic reagent to obtain a metal salt of the intermediate II, and then carry out an addition reaction with compound III. After the reaction is completed, quench with water or a saturated NH 4 Cl solution; alternatively, carry out a substitution reaction between the metal salt of the intermediate II and compound IV to obtain a ligand compound;

[0029] S5: React the ligand compound described in S4 with an organometallic reagent to obtain a metal salt of the ligand compound, and then react with MX 4 or its ether complex to obtain the dual-active-site metallocene complex;

[0030]

[0031] wherein, Cp 1 , Cp 2 , Cp 3 , R 1 , R 2 , X, and M are each independently as described above.

[0032] In the preparation method provided by the present invention, in formula (IV), X 1 is selected from halogens, preferably Cl.

[0033] In the preparation method provided by the present invention, compound III and compound IV can be commercially available products or can be prepared with reference to the prior art.

[0034] As a preferred scheme, in step S1 of the present invention, the solvent is one or more of benzene, toluene, xylene, chlorobenzene, n-hexane, n-heptane, dichloromethane, 1,2-dichloroethane, tetrachloroethane, tetrahydrofuran, 2-methyltetrahydrofuran, diethyl ether, n-propyl ether, isopropyl ether, methyl tert-butyl ether, ethylene glycol dimethyl ether, and dioxane, preferably one or more of tetrahydrofuran, 2-methyltetrahydrofuran, diethyl ether, and methyl tert-butyl ether.

[0035] As a preferred embodiment, in step S1 of the present invention, the alkyllithium is one or more of C1-C6 alkyllithiums, preferably one or more of methyllithium, n-butyllithium, and n-hexyllithium.

[0036] As a preferred embodiment, in step S1 of the present invention, the concentration of the hydrochloric acid aqueous solution is 0.1-10N, preferably 1-2N.

[0037] As a preferred embodiment, in step S1 of the present invention, the molar ratio of 2-bromo-2'-iodobiphenyl, alkyllithium, trimethyl borate, and hydrochloric acid is 1:(0.5-3):(0.5-10):(1-50), preferably 1:(0.5-1.5):(0.5-4):(2-20).

[0038] As a preferred embodiment, in step S1 of the present invention, the amount of the solvent used is 0.1-100 mL of solvent added per millimole of 2-bromo-2'-iodobiphenyl, preferably 1-10 mL of solvent added per millimole of 2-bromo-2'-iodobiphenyl.

[0039] As a preferred embodiment, in step S1 of the present invention, when adding alkyllithium and trimethyl borate, the temperature of the reaction system is -80 to 40°C, preferably -80 to 0°C. After adding alkyllithium, the temperature of the reaction system is -80 to 40°C, preferably -80 to -40°C, and the reaction time is 0.1-100 h, preferably 0.1-10 h. After adding trimethyl borate, the temperature of the reaction system is -80 to 40°C, preferably 0 to 25°C, and the reaction time is 0.1-100 h, preferably 1-10 h.

[0040] As a preferred embodiment, in step S1 of the present invention, when adding the hydrochloric acid aqueous solution, the temperature of the reaction system is -80 to 40°C, preferably -10 to 10°C. After adding the hydrochloric acid aqueous solution, the temperature of the reaction system is -80 to 40°C, preferably 0 to 25°C, and the reaction time is 0.1-100 h, preferably 1-10 h.

[0041] As a preferred embodiment, in step S1 of the present invention, the reaction is carried out in an N 2 or Ar atmosphere; after the reaction is completed, it also includes post-treatment processes such as separation and purification, which are conventional operations in the art and are not particularly required in the present invention. For example, in some specific embodiments, the methods that can be adopted include: rotary evaporation or removal of the solvent under reduced pressure, extraction and liquid separation using water, dichloromethane (DCM), or ethyl acetate, anhydrous Na 2 SO 4 or MgSO 4 drying, and then purifying the target product by column chromatography, recrystallization, or slurrying with an organic solvent.

[0042] As a preferred embodiment, in step S2 of the present invention, the Cp 1 halide is selected from 5-iodo-1H-indene, 6-iodo-1H-indene, 2-iodo-9H-fluorene.

[0043] As a preferred embodiment, in step S2 of the present invention, the base is NaOH, KOH, Ba(OH) 2 , Ca(OH) 2 , K 2 CO 3 , K 3 PO 4 , Na 2 CO 3 , Cs 2 CO 3 , TlOH, KF, CsF, Bu 4 NF, NaOCH 2 CH 3 , N(CH 2 CH 3 ) 3 , etc., and one or more of them are preferred to be NaOH, KOH, K 2 CO 3 , Na 2 CO 3 , Cs 2 CO 3 among one or more of them.

[0044] As a preferred embodiment, in step S2 of the present invention, the palladium catalyst is Pd(PPh 3 ) 4 , Pd(dppf)Cl 2 , Pd(OAc) 2 , PdCl 2 , PdCl 2 (PPh 3 ) 2 , Pd(OAc) 2 (PPh 3 ) 2 , Pd(OAc) 2 (P(Cy) 3 ) 2 , Pd(P t Bu 3 ) 2 , PdCl 2 (P(Cy) 3 ) 2 , PdCl(Bn)(PPh 3 ) 2 , Pd 2 (dba)3 One or more of them, preferably Pd(PPh 3 ), 4 Pd(dppf)Cl 2 Pd(P t Bu 3 ), 2 Pd 2 (dba) 3 One or more of them.

[0045] As a preferred embodiment, step S2 of the present invention is carried out in the presence of a solvent, and the solvent is one or more of benzene, toluene, xylene, chlorobenzene, n-hexane, n-heptane, dichloromethane, 1,2-dichloroethane, tetrachloroethane, tetrahydrofuran, 2-methyltetrahydrofuran, ether, n-propyl ether, isopropyl ether, methyl tert-butyl ether, ethylene glycol dimethyl ether, dioxane, water, methanol, ethanol, isopropanol, preferably one or more of toluene, xylene, dioxane, water, ethanol.

[0046] As a preferred embodiment, in step S2 of the present invention, the molar ratio of the compound A, the halide of Cp 1 , the base, and the palladium catalyst is 1:(0.1-100):(0.1-100):(0.0001-1), preferably 1:(0.1-10):(0.1-10):(0.001-0.1).

[0047] As a preferred embodiment, in step S2 of the present invention, the amount of the solvent used is 0.1-1000 mL of the solvent added per millimole of the compound A, preferably 1-100 mL of the solvent added per millimole of the compound A.

[0048] As a preferred embodiment, in step S2 of the present invention, the reaction temperature is 0-160 °C, preferably 40-130 °C.

[0049] As a preferred embodiment, in step S2 of the present invention, the reaction time is 0.1-100 h, preferably 1-10 h.

[0050] As a preferred embodiment, in step S2 of the present invention, the reaction is carried out in an N 2 or Ar atmosphere; after the reaction is completed, it also includes post-treatment processes such as separation and purification, which are conventional operations in the art and are not particularly required in the present invention. For example, in some specific embodiments, the methods that can be adopted include: rotary evaporation or removal of the solvent under reduced pressure, extraction and liquid separation using water, dichloromethane (DCM) or ethyl acetate, drying with anhydrous Na 2 SO 4 or MgSO 4 , and then purifying the target product by column chromatography, recrystallization or slurrying with an organic solvent.

[0051] As a preferred embodiment, in step S3 of the present invention, the boronic acid compound of Cp2 is selected from 6-indene boronic acid, 5-indene boronic acid, 2-fluorene boronic acid, 6-indene boronic acid pinacol ester, 5-indene boronic acid pinacol ester, and 2-fluorene boronic acid pinacol ester.

[0052] As a preferred embodiment, in step S3 of the present invention, the base is one or more of NaOH, KOH, Ba(OH) 2 , Ca(OH) 2 , K 2 CO 3 , K 3 PO 4 , Na 2 CO 3 , Cs 2 CO 3 , TlOH, KF, CsF, Bu 4 NF, NaOCH 2 CH 3 , N(CH 2 CH 3 ) 3 and the like, preferably one or more of NaOH, KOH, K 2 CO 3 , Na 2 CO 3 , Cs 2 CO 3 .

[0053] As a preferred embodiment, in step S3 of the present invention, the palladium catalyst is Pd(PPh 3 ) 4 , Pd(dppf)Cl 2 , Pd(OAc) 2 , PdCl 2 , PdCl 2 (PPh 3 ) 2 , Pd(OAc) 2 (PPh 3 ) 2 , Pd(OAc) 2 (P(Cy) 3 ) 2 , Pd(P t Bu 3 ) 2 , PdCl 2 (P(Cy) 3 ) 2 , PdCl(Bn)(PPh 3 ) 2 , Pd 2 (dba) 3One or more of them, preferably Pd(PPh 3 ) 4 、Pd(dppf)Cl 2 、Pd(P t Bu 3 ) 2 、Pd 2 (dba) 3 One or more of them.

[0054] As a preferred embodiment, step S3 of the present invention is carried out in the presence of a solvent, and the solvent is one or more of benzene, toluene, xylene, chlorobenzene, n-hexane, n-heptane, dichloromethane, 1,2-dichloroethane, tetrachloroethane, tetrahydrofuran, 2-methyltetrahydrofuran, ether, n-propyl ether, isopropyl ether, methyl tert-butyl ether, ethylene glycol dimethyl ether, dioxane, water, methanol, ethanol, isopropanol, preferably one or more of toluene, xylene, dioxane, water, ethanol.

[0055] As a preferred embodiment, in step S3 of the present invention, the molar ratio of the compound B, the boric acid compound of Cp 2 , the base, and the palladium catalyst is 1:(0.1-100):(0.1-100):(0.0001-1), preferably 1:(0.1-10):(0.1-10):(0.001-0.1).

[0056] As a preferred embodiment, in step S3 of the present invention, the amount of the solvent used is 0.1-1000 mL of the solvent added per millimole of the compound B, preferably 1-100 mL of the solvent added per millimole of the compound B.

[0057] As a preferred embodiment, in step S3 of the present invention, the reaction temperature is 0-160 °C, preferably 40-130 °C.

[0058] As a preferred embodiment, in step S3 of the present invention, the reaction time is 0.1-100 h, preferably 1-10 h.

[0059] As a preferred embodiment, in step S3 of the present invention, the reaction is carried out in an N 2 or Ar atmosphere; after the reaction is completed, post-treatment processes such as separation and purification are also included, which are conventional operations in the art and are not particularly required in the present invention. For example, in some specific embodiments, the methods that can be adopted include: rotary evaporation or removing the solvent under reduced pressure, extraction and liquid separation using water, dichloromethane (DCM) or ethyl acetate, drying with anhydrous Na 2 SO 4 or MgSO 4 , and then purifying the target product by column chromatography, recrystallization or slurrying with an organic solvent.

[0060] As a preferred embodiment, in step S4 of the present invention, the compound III is selected from 6,6-dimethylfulvene, 6,6-diphenylfulvene, 6-methyl-6-phenylfulvene.

[0061] As a preferred embodiment, in step S4 of the present invention, the alkyl metal reagent is one or more of C1-C6 alkyllithiums, preferably one or more of methyllithium, n-butyllithium, n-hexyllithium.

[0062] As a preferred embodiment, step S4 of the present invention is carried out in the presence of a solvent, and the solvent is one or more of benzene, toluene, xylene, chlorobenzene, n-hexane, n-heptane, dichloromethane, 1,2-dichloroethane, tetrachloroethane, tetrahydrofuran, 2-methyltetrahydrofuran, ether, n-propyl ether, isopropyl ether, methyl tert-butyl ether, ethylene glycol dimethyl ether, dioxane, preferably one or more of toluene, n-hexane, n-heptane, tetrahydrofuran, ether.

[0063] As a preferred embodiment, in step S4 of the present invention, the molar ratio of the intermediate II, the alkyl metal reagent, and the compound III is 1:(1-10):(1-10), preferably 1:(1-3):(1-3).

[0064] As a preferred embodiment, in step S4 of the present invention, the compound IV is selected from dimethylcyclopentadienylchlorosilane, cyclopentadienyldiphenylchlorosilane, methylcyclopentadienylphenylchlorosilane.

[0065] In step S4 of the present invention, the molar ratio of the intermediate II, the alkyl metal reagent, and the compound IV is 1:(1-10):(1-10), preferably 1:(1-3):(1-3).

[0066] As a preferred embodiment, in step S4 of the present invention, the amount of the solvent used is 0.1-100 mL of the solvent added per millimole of the intermediate II, preferably 1-10 mL of the solvent added per millimole of the intermediate II.

[0067] As a preferred embodiment, in step S4 of the present invention, when adding the alkyl metal reagent, the compound III or the compound IV, the temperature of the reaction system is -80 to 40 °C, preferably -80 to 0 °C. After adding the alkyl metal reagent, the temperature of the reaction system is -80 to 40 °C, preferably 0 to 40 °C, and the reaction time is 0.1-100 h, preferably 0.1-10 h. After adding the compound III or the compound IV, the temperature of the reaction system is -80 to 40 °C, preferably 0 to 25 °C, and the reaction time is 0.1-100 h, preferably 1-10 h.

[0068] As a preferred embodiment, in step S4 of the present invention, when adding water or saturated NH 4 Cl solution, the temperature of the reaction system is -80 to 40 °C, preferably -10 to 10 °C.

[0069] As a preferred embodiment, in step S4 of the present invention, the reaction is carried out in an N 2 or Ar atmosphere; after the reaction, post-treatment processes such as separation and purification are also included, which are conventional operations in the art and are not particularly required in the present invention. For example, in some specific embodiments, the methods that can be adopted include: rotary evaporation or removal of the solvent under reduced pressure, extraction and liquid separation using water, dichloromethane (DCM) or ethyl acetate, etc., and anhydrous Na 2 SO 4 or MgSO 4 drying, and then purifying the target product by column chromatography, recrystallization or slurrying with an organic solvent.

[0070] As a preferred embodiment, in step S5 of the present invention, the organometallic reagent is one or more of C1-C6 alkyllithiums, preferably one or more of methyllithium, n-butyllithium, and n-hexyllithium.

[0071] As a preferred embodiment, in step S5 of the present invention, the ether is one or more of tetrahydrofuran, 2-methyltetrahydrofuran, diethyl ether, n-propyl ether, isopropyl ether, methyl tert-butyl ether, ethylene glycol dimethyl ether, and dioxane, preferably one or more of tetrahydrofuran, diethyl ether, and n-propyl ether.

[0072] As a preferred embodiment, step S5 of the present invention is carried out in the presence of a solvent, and the solvent is one or more of benzene, toluene, xylene, chlorobenzene, n-hexane, n-heptane, dichloromethane, 1,2-dichloroethane, tetrachloroethane, tetrahydrofuran, 2-methyltetrahydrofuran, diethyl ether, n-propyl ether, isopropyl ether, methyl tert-butyl ether, ethylene glycol dimethyl ether, and dioxane, preferably one or more of toluene, n-hexane, n-heptane, tetrahydrofuran, and diethyl ether.

[0073] As a preferred embodiment, in step S5 of the present invention, the molar ratio of the ligand compound, the organometallic reagent, and MX 4 (or its ether complex) is 1:(0.1-100):(0.1-100), preferably 1:(1-10):(1-10).

[0074] As a preferred embodiment, in step S5 of the present invention, the amount of the solvent used is 0.1-1000 mL of the solvent added per millimole of the ligand compound, preferably 1-100 mL of the solvent added per millimole of the ligand.

[0075] As a preferred embodiment, in step S5 of the present invention, the reaction temperature of the ligand compound and the organometallic reagent is -80 to 50 °C, preferably -10 to 35 °C, and the metal salt of the ligand compound and MX 4(or its ether complex) has a reaction temperature of -80 to 50 °C, preferably -10 to 35 °C. The reaction time of the ligand compound with the organometallic reagent is 0.1 to 100 h, preferably 0.1 to 20 h. The reaction time of the metal salt of the ligand compound with MX 4 (or its ether complex) is 0.1 to 100 h, preferably 1 to 50 h.

[0076] As a preferred embodiment, in step S5 of the present invention, the reaction is carried out in an N 2 or Ar atmosphere; after the reaction, post-treatment processes such as separation and purification are also included, which are conventional operations in the art and are not particularly required in the present invention. For example, in some specific embodiments, the methods that can be adopted include: filtering to separate the filtrate and the solid residue, removing the solvent under reduced pressure, and purifying the target product by recrystallization or slurrying with an organic solvent.

[0077] The third aspect of the present invention provides the use of the biphenyl-bridged bis-active center metallocene complex described above as an olefin polymerization catalyst.

[0078] The complex structure provided by the present invention contains a bis-metallocene active center and is bridged by a biphenyl group, thereby enabling a specific spacing, coordination space, and electron distribution between the two metal active centers. Therefore, it can effectively exert the "metal-metal" synergistic catalytic effect of the bis-active center, has extremely high catalytic activity when used in catalytic olefin polymerization reactions, and also has good high-temperature resistance, can withstand higher polymerization temperatures, and thus has better thermal stability, which is beneficial to extending the service life. In addition, the complex provided by the present invention has stronger flexibility in structure. Through the free rotation of the Cp 1 -Ph-Ph-Cp 2 carbon-carbon bond in the middle can provide a suitable coordination space for the polymerization reaction, which is beneficial to the insertion of bulky comonomers (such as cycloolefin monomers) into the polymer. Therefore, the complex provided by the present invention is very suitable for catalytic olefin polymerization reactions, especially the copolymerization of ethylene and / or α-olefins with cycloolefins.

[0079] In the use provided by the present invention, the olefin polymerization is the copolymerization of ethylene and / or α-olefins with cycloolefins. In some preferred embodiments, the α-olefin is an α-olefin having 3 to 12 carbon atoms, including but not limited to one or more of 1-propene, 1-butene, 1-pentene, 1-hexene, 1-heptene, and 1-octene, and the cycloolefin is a cycloolefin having 6 to 21 carbon atoms, including but not limited to one or more of cyclohexene, norbornene, and tetracyclododecene.

[0080] The fourth aspect of the present invention provides a method for olefin polymerization, which polymerization method comprises the following steps: in the presence of a main catalyst and a cocatalyst, ethylene and / or an α-olefin are polymerized with a cycloolefin to form a copolymer of olefins; wherein, the main catalyst is the biphenyl-bridged bis-active center metallocene complex described above.

[0081] In the polymerization method of the present invention, the α-olefin is an α-olefin having 3 to 12 carbon atoms, including but not limited to one or more of 1-propene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, and the cycloolefin is a cycloolefin having 6 to 21 carbon atoms, including but not limited to one or more of cyclohexene, norbornene, tetracyclododecene.

[0082] In the polymerization method of the present invention, the molar ratio of the main catalyst to the cocatalyst is 1:1 to 5000. In some preferred embodiments, the molar ratio of the main catalyst to the cocatalyst is 1:1 to 2000, such as 1:1, 1:2, 1:4, 1:6, 1:8, 1:10, 1:20, 1:40, 1:60, 1:80, 1:100, 1:200, 1:400, 1:600, 1:800, 1:1000, 1:1200, 1:1500, 1:1800, 1:2000, or any combination of molar ratio ranges. In some more preferred embodiments, the molar ratio of the main catalyst to the cocatalyst is 1:1 to 1500.

[0083] In the polymerization method of the present invention, the cocatalyst can be any common type in the art. In some preferred embodiments, the cocatalyst is selected from one or more of alkylaluminums, alkylaluminum chlorides, aluminoxanes, boron-containing cocatalysts. In some more preferred embodiments, the alkylaluminum is selected from one or more of trimethylaluminum, triethylaluminum, triisobutylaluminum, tri-n-hexylaluminum; the alkylaluminum chloride is selected from one or more of diethylaluminum chloride, dichloroethylaluminum, sesqui-diethylaluminum chloride; the aluminoxane is selected from one or more of methylaluminoxane, ethylaluminoxane, isobutylaluminoxane; the boron-containing cocatalyst is selected from one or two of tris(pentafluorophenyl)borane, triphenylcarbenium tetrakis(pentafluorophenyl)borate, etc.

[0084] In the polymerization method of the present invention, as a preferred embodiment, the cocatalyst is selected from methylaluminoxane (MAO); or the cocatalyst is selected from a combination of methylaluminoxane and triisobutylaluminum in a molar ratio of 1 to 50:1, including but not limited to molar ratios of 1:1, 2:1, 5:1, 10:1, 15:1, 20:1, 25:1, 30:1, 35:1, 40:1, 45:1, 50:1, or any combination within the molar ratio range. In some preferred embodiments, the cocatalyst is selected from a combination of methylaluminoxane and triisobutylaluminum in a molar ratio of 2 to 30:1.

[0085] In the polymerization method of the present invention, as a preferred embodiment, the cocatalyst is selected from a combination of a boron-containing additive and an alkylaluminum; the cocatalyst is selected from a combination of a boron-containing additive and an alkylaluminum in a molar ratio of 1:1 to 3000, including but not limited to molar ratios of 1:10, 1:20, 1:50, 1:100, 1:150, 1:200, 1:250, 1:300, 1:350, 1:400, 1:450, 1:500, or any combination within the molar ratio range. In some preferred embodiments, the cocatalyst is selected from a combination of triphenylcarbenium tetrakis(pentafluorophenyl)borate and triisobutylaluminum in a molar ratio of 1:500.

[0086] In the polymerization method of the present invention, by adjusting the catalyst structure, the characteristics of the prepared polymerization products can be adjusted within a relatively wide range, especially the molecular weight distribution of copolymers (such as copolymers of ethylene and norbornene), or a copolymer with a bimodal molecular weight distribution can be obtained. Moreover, even when the polymerization is carried out at a relatively high temperature (130 °C), the polymerization activity of the catalyst will not be significantly sacrificed and can still be maintained at a relatively high level (as shown in Table 1 and Table 2).

[0087] In the polymerization method of the present invention, the reaction temperature of the polymerization reaction is 50 to 200 °C, and within this range, those skilled in the art can make appropriate adjustments according to the actual reaction conditions such as the type of polymerization and the type of polymerization monomers. In some preferred embodiments, the reaction temperature of the polymerization reaction is 90 to 180 °C. In some more preferred embodiments, the reaction temperature of the polymerization reaction is higher than 110 °C, such as 110 to 140 °C.

[0088] The biphenyl-bridged bis-active center metallocene complex of the present invention has good high-temperature stability and can still maintain a relatively high polymerization activity at a relatively high reaction temperature (such as at 150 °C), while the polymerization temperatures that the commonly used catalysts in the art (including single- or double-active center metallocenes, or single- or double-active center non-metallocene catalysts) can tolerate do not exceed 130 °C.

[0089] In the polymerization method of the present invention, the reaction pressure of the polymerization reaction is 0.01 - 10 MPa, and within this range, those skilled in the art can make appropriate adjustments according to the actual reaction conditions such as the polymerization type and the type of polymerization monomer. In some preferred embodiments, the reaction pressure of the polymerization reaction is 0.1 - 3 MPa.

[0090] In the polymerization method of the present invention, the reaction time of the polymerization reaction is 0.1 - 1000 min, and within this range, those skilled in the art can make appropriate adjustments according to the actual reaction conditions such as the polymerization type and the type of polymerization monomer. In some preferred embodiments, the reaction time of the polymerization reaction is 1 - 100 min, for example, it can be 1 - 30 min.

[0091] The polymerization method of the present invention can be a solution polymerization process, that is, the polymerization reaction is carried out in a solvent, and the solvent used can be any common type in the art.

[0092] In the polymerization method of the present invention, other process steps, post-treatment steps, etc. except the above process parameters can all adopt conventional techniques in the art, or can be appropriately adjusted by those skilled in the art according to the actual reaction conditions such as the polymerization type and the type of polymerization monomer.

[0093] The technical solution provided by the present invention has the following advantages:

[0094] (1) The complex provided by the present invention includes a bis(cyclopentadienyl) metal active center bridged by a biphenyl group, with a novel structure, extremely high catalytic activity, and good high-temperature resistance, and is very suitable for catalyzing the polymerization reaction of olefins, especially the copolymerization reaction of ethylene and / or α-olefin with cycloolefin.

[0095] (2) Compared with the single-active-center metallocene complex catalyst, the complex provided by the present invention can adjust the molecular weight distribution of the polymerization product through catalyst structure adjustment, and can prepare bimodal COC with the same or different cycloolefin insertion rates, thereby obtaining polymers with different mechanical strengths and toughness, and expanding its variety and application range.

[0096] (3) The preparation method of the complex provided by the present invention is simple, without complex process steps and high costs, and can adapt to large-scale production and use.

[0097] (4) The olefin polymerization method provided by the present invention has high polymerization activity, simple process, strong operability, can adapt to a variety of olefin monomers, especially cycloolefin monomers with large steric hindrance, and has very important industrial value and economic value. Description of the Drawings

[0098] Figure 1It is the molecular weight distribution curve of the copolymerization product of ethylene and norbornene catalyzed by Cat.5. Detailed implementation mode

[0099] Term

[0100] As used herein, "C1-Cn" includes C1-C2, C1-C3, …… C1-Cn. For example, the group "C1-C10" means that this part has 1 to 10 carbon atoms, that is, the group contains 1 carbon atom, 2 carbon atoms, 3 carbon atoms, 4 carbon atoms, 5 carbon atoms, 6 carbon atoms, 7 carbon atoms, 8 carbon atoms, 9 carbon atoms or 10 carbon atoms. Therefore, for example, "C1-C4 alkyl" means an alkyl group containing 1 to 4 carbon atoms, that is, the alkyl group is selected from methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl and tert-butyl. The numerical ranges in this article, such as "1-6", refer to each integer in the given range.

[0101] The term "alkyl" used alone or in combination herein refers to an optionally substituted straight-chain or optionally substituted branched-chain saturated aliphatic hydrocarbon. The "alkyl" herein preferably may have 1 to 10 carbon atoms, for example, having 1 to 8 carbon atoms, or having 1 to 6 carbon atoms, or having 1 to 5 carbon atoms, or having 1 to 4 carbon atoms, or having 1-3 carbon atoms. Non-limiting examples of alkyl include methyl, ethyl, n-propyl, isopropyl, 2-methyl-1-propyl, 2-methyl-2-propyl, 2-methyl-1-butyl, 3-methyl-1-butyl, 2-methyl-3-butyl, 2,2-dimethyl-1-propyl, 2-methyl-1-pentyl, 3-methyl-1-pentyl, 4-methyl-1-pentyl, 2-methyl-2-pentyl, 3-methyl-2-pentyl, 4-methyl-2-pentyl, 2,2-dimethyl-1-butyl, 3,3-dimethyl-1-butyl, 2-ethyl-1-butyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, neopentyl, tert-pentyl and hexyl, as well as longer alkyl groups such as heptyl and octyl. When a numerical range appears in a group defined herein, such as "alkyl", for example, "C1-C6 alkyl" means an alkyl group that can be composed of 1 carbon atom, 2 carbon atoms, 3 carbon atoms, 4 carbon atoms, 5 carbon atoms or 6 carbon atoms. The alkyl herein also includes cases where no numerical range is specified.

[0102] The "alkyl" used in combination herein refers to an alkyl group connected to other groups. For example, the alkyl in alkoxy has the same definition as when used alone.

[0103] The term "alkoxy" used alone or in combination herein refers to an alkyl ether group, represented as "alkyl-O-". Non-limiting examples of alkoxy include methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy, etc.

[0104] The term "cycloalkyl", as used herein alone or in combination, refers to a non-aromatic saturated carbon ring, which may include a monocyclic ring (with one ring), a bicyclic ring (with two rings), or a polycyclic ring (with more than two rings), and the rings may be bridged or spiro. The cycloalkyl may have 3 to 10 ring-forming carbon atoms, such as 3 to 8 ring-forming carbon atoms, or 3 to 6 ring-forming carbon atoms. Non-limiting examples of cycloalkyl include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, etc.

[0105] The term "aryl", as used herein alone or in combination, refers to an optionally substituted aromatic hydrocarbon group having 6 to 20, such as 6 to 12 or 6 to 10 ring-forming carbon atoms, which may be a monocyclic aryl, a bicyclic aryl, or a polycyclic aryl. The bicyclic aryl or polycyclic aryl may be a monocyclic aryl fused with other independent rings, such as an alicyclic ring or an aromatic ring. Non-limiting examples of monocyclic aryl include phenyl; non-limiting examples of bicyclic aryl include naphthyl; non-limiting examples of polycyclic aryl include phenanthryl, anthryl, fluorenyl, azulyl.

[0106] The term "halogen", as used herein alone or in combination, refers to fluorine, chlorine, bromine, or iodine.

[0107] The term "α-olefin", as used herein alone or in combination, refers to a monoolefin with a double bond at the end of the molecular chain, and its molecular formula can be represented as R-CH=CH 2 , where R represents "C1-C10 alkyl". The olefin has, but is not limited to, 3 to 12 carbon atoms. For example, it has 3 to 12 carbon atoms, or 3 to 10 carbon atoms, or 3 to 8 carbon atoms. The double bond in these groups can be in a cis or trans conformation, and should be understood to include both isomers. The olefin defined herein can be a single type of olefin or a mixture of multiple olefins.

[0108] The technical solutions of the present invention will be further described in detail below in conjunction with specific embodiments.

[0109] The reagents or raw materials used in the embodiments of the present invention are all commercially available products unless otherwise specified.

[0110] Unless otherwise specified, the percentages used in the embodiments of the present invention are all mass percentages.

[0111] The test methods used in the embodiments of the present invention are as follows:

[0112] Polymer molecular weight (M w ) and molecular weight distribution (PDI, M w / M n)Determined by high-temperature gel permeation chromatography (PL-GPC220), using 1,2,4-trichlorobenzene as the mobile phase, polystyrene as the standard sample, and measured at 150 °C. The concentration of the standard sample is 0.1 mg / mL, the solvent flow rate is 1.0 mL / min, the parameters of the standard sample are K = 59.1 and α = 0.69, and the parameters of the sample are K = 14.1 and α = 0.70.

[0113] The melting point (T m ) and glass transition temperature (T g ) of the polymer were measured by differential scanning calorimetry (METTLER, DSC-1). The measurement procedure is as follows: Take 5.0 - 7.0 mg of the polymer sample, heat it to 250 °C at a rate of 30 °C / min and maintain it for 5 min to eliminate the thermal history, then cool it to 0 °C at a rate of 10 °C / min and keep it constant for 3 min, and then heat it to 250 °C again. The crystallization peak temperature is obtained from the cooling curve, and the melting point or glass transition temperature of the polymer is calculated from the curve of the second heating process.

[0114] The copolymerization monomer insertion rate in the copolymer of ethylene and α-olefin or cycloolefin is determined by 13 13C NMR (Bruker ADVANCEⅢ400M). The polymer is dissolved in deuterated 1,2-dichlorobenzene at 130 °C, and the concentration is about 100 mg / mL. Instrument test parameters: The pulse angle is 30 degrees, full decoupling, the pulse delay time is 3 s, and the number of sample scans is more than 3000 times. After assigning the peaks of the obtained high-temperature 13 13C NMR spectrum, the sequence distribution and copolymerization monomer insertion rate of the copolymer are obtained.

[0115] The tensile experiment uses an electronic universal material testing machine from Instron Corporation of the United States to test the tensile mechanical properties of the polymer, and obtain the stress-strain curve and related mechanical parameters of the polymer.

[0116] Preparation of Cat.1 Complex in Example 1

[0117]

[0118] The synthesis route of Cat.1 is as follows:

[0119]

[0120]

[0121] (1) Preparation of Compound A: In N 2Under this atmosphere, in a 500 mL Schlenk flask, 20 mmol of 2-bromo-2'-iodobiphenyl (Ref. Adv. Synth. Catal. 2007, 349, 2705-2713) and 100 mL of ultra-dry THF were added respectively. At -78 °C, 20 mmol of n-BuLi (1.6 M hexane solution) was added dropwise and the reaction was carried out for 30 min. Then 20 mmol of B(OMe) 3 was added, and the temperature was slowly raised to 25 °C and the reaction was carried out for 12 h. After the reaction was completed, 40 mL of 2N HCl was added at 0 °C, and the mixture was stirred at 25 °C for 1 h. 100 mL of water was added. After the reaction mixture was allowed to stand and layer, the organic phase was collected, and the aqueous phase was extracted with EtOAc (50 mL×3). After all the organic phases were mixed, they were dried over anhydrous MgSO 4 . After filtration, the solvent in the filtrate was removed by rotary evaporation to obtain a white solid product. The white solid product was further purified by washing with n-hexane (100 mL×3) to obtain a white solid powder, which was compound A with a yield of 80%.

[0122] 1 H NMR (500 MHz, Chloroform-d) δ 7.69–7.63 (m, 1H), 7.61 (dd, J = 7.4, 1.7 Hz, 1H), 7.56 (dd, J = 7.3, 1.7 Hz, 1H), 7.51–7.46 (m, 1H), 7.40 (td, J = 7.4, 1.6 Hz, 1H), 7.37–7.30 (m, 3H), 6.46 (s, 2H).

[0123] (2) Preparation of compound B: In a 200 mL Schlenk flask, 15 mmol of compound A, 15 mmol of 6-iodo-1H-indene and 80 mmol of Na 2 CO 3 were added respectively. Then 60 mL of toluene, 20 mL of ethanol and 20 mL of water were added respectively. After freezing and degassing 3 times, under N 2 atmosphere, 1 mmol of Pd(PPh 3 ) 4 was added to the mixed solution, and the temperature was raised to 80 °C and stirred for 13 h. After the reaction mixture was allowed to stand and layer, the organic phase was collected, and the aqueous phase was extracted with dichloromethane (30 mL×3). After all the organic phases were mixed, they were dried over anhydrous MgSO 4 . Then the organic phase filtrate was obtained by filtration. The filtrate was concentrated by rotary evaporation to ~30 mL and recrystallized at -18 °C to obtain a white crystalline solid, which was compound B with a yield of 78%.

[0124] 11H NMR (500 MHz, Chloroform-d) δ 7.74 (dd, J = 7.5, 0.7 Hz, 1H), 7.64 (dd, J = 7.3, 1.7 Hz, 1H), 7.62–7.53 (m, 3H), 7.52–7.44 (m, 4H), 7.40 (td, J = 7.4, 1.7 Hz, 1H), 7.35 (td, J = 7.3, 1.6 Hz, 1H), 7.07–7.01 (m, 1H), 6.26 (dt, J = 11.1, 6.1 Hz, 1H), 5.74 (dd, J = 6.2, 1.0 Hz, 2H).

[0125] (3) Preparation of Intermediate II: In a 200 mL Schlenk flask, 10 mmol of Compound B, 10 mmol of 2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-9H-fluorene, and 60 mmol of Na 2 CO 3 were added respectively. Then, 80 mL of toluene, 20 mL of ethanol, and 20 mL of water were added respectively. After freezing and degassing three times, under a N 2 atmosphere, 1 mmol of Pd(PPh 3 ) 4 was added to the mixed solution. The temperature was raised to 80 °C and the mixture was stirred for 13 h. After the reaction mixture was allowed to stand and separate into layers, the organic phase was collected. The aqueous phase was extracted with dichloromethane (30 mL × 3). After all the organic phases were combined, they were dried over anhydrous MgSO 4 . Then, the mixture was filtered to obtain the filtrate of the organic phase. The filtrate was concentrated by rotary evaporation to ~50 mL and recrystallized at -18 °C to obtain a white solid, which was Intermediate II with a yield of 70%.

[0126] 1 1H NMR (500 MHz, Chloroform-d) δ 7.88–7.79 (m, 2H), 7.66 (d, J = 7.4 Hz, 1H), 7.62–7.54 (m, 6H), 7.54–7.45 (m, 3H), 7.49–7.42 (m, 5H), 7.39 (td, J = 7.5, 1.6 Hz, 1H), 7.07–7.01 (m, 1H), 6.37 (dt, J = 10.7, 6.2 Hz, 1H), 5.74 (dd, J = 6.2, 1.0 Hz, 2H), 3.95 (s, 2H).

[0127] (4) Preparation of Ligand for Cat.1: Under N 2Under an inert atmosphere, 6 mmol of Intermediate II was dissolved in 100 mL of anhydrous THF in a 200 mL Schlenk flask and placed in an ice-water bath. 12 mmol of n-BuLi (1.6 M hexane solution) was added dropwise to the above reaction solution at 0 °C (the solution gradually changed from colorless to dark red), and then the reaction was carried out at 25 °C for 3 h to obtain a lithium salt solution of Intermediate II. 13.2 mmol of 6,6-dimethylfulvene was dissolved in 20 mL of anhydrous THF and added to the lithium salt solution of Intermediate II at -78 °C (it became a dark red suspension), and slowly warmed to 25 °C and stirred for 15 h. After the reaction was completed, 10 mL of saturated NH 4 Cl solution was slowly added to the above reaction solution at 0 °C to quench the reaction, and then extracted with dichloromethane (50 mL × 3). After mixing all the organic phases, they were dried over anhydrous MgSO 4 4. After filtration, the solvent in the filtrate was removed by rotary evaporation to obtain a yellow solid product. The yellow solid product was further purified by washing with EtOH (100 mL × 3) to obtain a pale yellow solid powder, which was the Cat.1 ligand with a yield of 81%.

[0128] 1 1H NMR (500 MHz, Chloroform-d) δ 7.83–7.78 (m, 2H), 7.66–7.54 (m, 6H), 7.52–7.43 (m, 9H), 7.42 (qd, J = 7.4, 1.3 Hz, 1H), 6.58 (dd, J = 10.9, 0.9 Hz, 1H), 6.52 (dtd, J = 10.9, 7.0, 1.3 Hz, 2H), 6.30 (ddd, J = 10.8, 6.9, 0.9 Hz, 2H), 6.14 (dd, J = 11.0, 6.2 Hz, 1H), 5.94 (dtt, J = 8.7, 6.2, 1.1 Hz, 2H), 5.82 (dq, J = 2.2, 1.4 Hz, 1H), 3.51–3.45 (m, 1H), 3.41 (dd, J = 7.0, 6.2 Hz, 2H), 3.33 (dd, J = 7.0, 6.2 Hz, 2H), 1.24 (d, J = 1.5 Hz, 3H), 1.19 (dd, J = 5.4, 1.5 Hz, 6H), 1.15 (d, J = 1.6 Hz, 3H).

[0129] (5) Preparation of Cat.1 complex: Under N 2Under an inert atmosphere, in a 200 mL Schlenk flask, 5 mmol of Cat.1 ligand was added to 100 mL of diethyl ether. At 0 °C, 21 mmol of n-BuLi (1.6 M hexane solution) was added dropwise to the reaction solution, and then the temperature was slowly raised to 25 °C and the reaction was carried out for 18 h. After filtration and drying, a light yellow solid (lithium salt of Cat.1 ligand) was obtained; the lithium salt of Cat.1 ligand and 10 mmol of ZrCl 4 were successively added to a 200 mL Schlenk flask, then 130 mL of toluene was added, and after reacting at 25 °C for 30 h, the resulting orange suspension was filtered, and then the residue was washed with toluene (30 mL × 3). The filtrate was collected, concentrated, and precipitated at -18 °C to obtain an orange solid powder, which was Cat.1 complex with a yield of 69%.

[0130] 1 H NMR (400 MHz, C 6 D 6 ): δ 7.79 - 7.63 (m, 4H), 7.52 (m, 4H), 7.38 - 7.25 (m, 4H), 7.20 (d, J = 7.1 Hz, 2H), 7.12 (t, J = 7.2 Hz, 2H), 7.10 (m, 2H), 6.84 (d, J = 3.2 Hz, 2H), 6.55 - 6.28 (m, 4H), 6.20 - 5.98 (m, 4H), 1.60 (m, 6H), 1.41 (m, 6H).

[0131] Example 2 Preparation of Cat.2 Complex

[0132]

[0133] The synthetic route of Cat.2 is as follows:

[0134]

[0135] (1) Preparation of Cat.2 Ligand: Under an N 2 inert atmosphere, in a 500 mL Schlenk flask, 6 mmol of Intermediate II was dissolved in 100 mL of anhydrous THF and placed in an ice-water bath; 12 mmol of n-BuLi (1.6 M hexane solution) was added dropwise to the above reaction solution at 0 °C (gradually changing from a colorless solution to a dark red solution), and then the reaction was carried out at 25 °C for 3 h to obtain a solution of lithium salt of Intermediate II; 13.2 mmol of 6-methyl-6-phenylfulvene was dissolved in 40 mL of anhydrous THF and added dropwise to the solution of lithium salt of Intermediate II at -78 °C (changing to a dark red suspension), and slowly raised to 25 °C and stirred for 15 h; after the reaction was completed, 10 mL of saturated NH 4The reaction was quenched by slowly adding Cl solution to the above reaction solution, and then extracted with dichloromethane (60 mL × 3). After mixing all the organic phases, they were dried over anhydrous MgSO 4 After drying, the solvent was removed from the filtrate by rotary evaporation to obtain a yellow solid product. The yellow solid product was further washed and purified with EtOH (100 mL × 3) to obtain a yellow solid powder, which was the ligand of Cat.2 with a yield of 80%.

[0136] 1 1H NMR (500 MHz, Chloroform-d) δ 7.83–7.76 (m, 2H), 7.64–7.57 (m, 4H), 7.56 (t, J = 1.0 Hz, 1H), 7.54–7.43 (m, 10H), 7.39 (td, J = 7.5, 1.4 Hz, 1H), 7.33–7.25 (m, 4H), 7.23 (dddd, J = 9.2, 7.6, 2.9, 1.6 Hz, 6H), 6.65–6.52 (m, 3H), 6.38–6.29 (m, 3H), 6.18 (dd, J = 11.0, 6.2 Hz, 1H), 6.00 (dtt, J = 11.7, 6.2, 1.1 Hz, 2H), 3.97–3.92 (m, 1H), 3.46–3.33 (m, 4H), 1.64 (d, J = 1.7 Hz, 3H), 1.56 (d, J = 1.4 Hz, 3H).

[0137] (2) Preparation of Cat.2 complex: Under N 2 atmosphere, in a 200 mL Schlenk flask, 5 mmol of the Cat.2 ligand was added to 100 mL of diethyl ether. At 0 °C, 21 mmol of n-BuLi (1.6 M hexane solution) was added dropwise to the reaction solution, and then slowly warmed to 25 °C and reacted for 18 h. After filtration and drying, a light yellow solid (lithium salt of the Cat.2 ligand) was obtained; the lithium salt of the Cat.2 ligand and 10 mmol of ZrCl 4 were successively added to a 200 mL Schlenk flask, and then 130 mL of toluene was added. After reacting at 25 °C for 30 h, the resulting orange-yellow suspension was filtered, and the residue was washed with toluene (50 mL × 3). The filtrate was collected, concentrated and then precipitated at -18 °C to obtain an orange-yellow solid powder, which was the Cat.2 complex with a yield of 65%.

[0138] 1 1H NMR (400 MHz, C 6 D 6): δ 7.81 - 7.68 (m, 4H), 7.59 (m, 4H), 7.40 - 7.24 (m, 4H), 7.21 (d, J = 7.2 Hz, 2H), 7.18 - 7.09 (m, 10H), 7.06 (t, J = 7.2 Hz, 2H), 7.01 (m, 2H), 6.88 (d, J = 3.0 Hz, 2H), 6.60 - 6.48 (m, 4H), 6.30 - 5.99 (m, 4H), 1.62 (s, 3H), 1.35 (s, 3H).

[0139] Preparation of Example 3 Cat.3 Complex

[0140]

[0141] The synthetic route of Cat.3 is as follows:

[0142]

[0143] (1) Preparation of Cat.3 Ligand: Under N 2 atmosphere, in a 200 mL Schlenk flask, dissolve 6 mmol of Intermediate II in 100 mL of anhydrous THF and place it in an ice - water bath; gradually add 12 mmol of n - BuLi (1.6 M hexane solution) dropwise to the above reaction solution at 0 °C (the colorless suspension gradually turns into a dark red solution), then react at 25 °C for 3 h to obtain a lithium salt solution of Intermediate II; dissolve 13.2 mmol of 6,6 - diphenylfulvene in 20 mL of anhydrous THF and add it dropwise to the lithium salt solution of Intermediate II at - 78 °C (it turns into a dark red suspension), slowly raise the temperature to 25 °C and stir the reaction for 15 h; after the reaction is completed, slowly add 10 mL of saturated NH 4 Cl solution to the above reaction solution at 0 °C to quench the reaction, then extract with dichloromethane (60 mL × 3), mix all the organic phases, dry with anhydrous MgSO 4 4, filter, and remove the solvent from the filtrate by rotary evaporation to obtain a yellow solid product. The yellow solid product is further purified by washing with EtOH (100 mL × 3) to obtain a white solid powder, which is the Cat.3 ligand with a yield of 85%.

[0144] 11H NMR (500 MHz, Chloroform-d) δ 7.81 (dd, J = 7.9, 1.8 Hz, 2H), 7.65–7.56 (m, 4H), 7.55–7.31 (m, 20H), 7.32–7.25 (m, 4H), 7.25–7.17 (m, 8H), 6.69 (s, 1H), 6.66–6.56 (m, 3H), 6.40–6.33 (m, 2H), 6.22 (dd, J = 11.0, 6.2 Hz, 1H), 6.05 (tt, J = 6.2, 1.1 Hz, 1H), 6.00 (tt, J = 6.1, 1.2 Hz, 1H), 4.29–4.24 (m, 1H), 3.41 (dd, J = 7.0, 6.1 Hz, 4H).

[0145] (2) Preparation of Cat.3 complex: Under N 2 atmosphere, in a 200 mL Schlenk flask, dissolve 5 mmol of Cat.3 ligand in 100 mL of diethyl ether. Dropwise add 21 mmol of n-BuLi (1.6 M hexane solution) to the reaction solution at 0 °C, then slowly raise the temperature to 25 °C and react for 18 h. After filtration and drying, a light yellow solid (lithium salt of Cat.3 ligand) is obtained; Add the lithium salt of Cat.3 ligand and 10 mmol of ZrCl 4 to a 200 mL Schlenk flask in sequence, then add 130 mL of toluene. After reacting at 25 °C for 30 h, filter the resulting orange-red suspension, then wash the residue with toluene (30 mL × 3), collect the filtrate, concentrate it and precipitate at -18 °C to obtain an orange-red solid powder, which is the Cat.3 complex with a yield of 66%.

[0146] 1 1H NMR (400 MHz, C 6 D 6 ): δ 7.81 - 7.70 (m, 4H), 7.62 (m, 4H), 7.56 - 7.44 (m, 4H), 7.40 (d, J = 7.0 Hz, 2H), 7.35 - 7.28 (m, 10H), 7.25 - 7.14 (m, 10H), 7.12 (t, J = 7.2 Hz, 2H), 7.10 (m, 2H), 6.89 (d, J = 3.2 Hz, 2H), 6.60 - 6.48 (m, 4H), 6.30 - 6.20 (m, 4H).

[0147] Example 4 Preparation of Cat.4 complex

[0148]

[0149] The synthetic route of Cat.4 is as follows:

[0150]

[0151] (1) Preparation of Cat.4 Ligand: Under N 2 atmosphere, in a 200 mL Schlenk flask, dissolve 6 mmol of Intermediate II in 100 mL of anhydrous THF, and place it in an ice-water bath; gradually add 12 mmol of n-BuLi (1.6 M hexane solution) dropwise to the above reaction solution at 0 °C (the solution gradually changes from colorless to dark red), and then react at 25 °C for 3 h to obtain a lithium salt solution of Intermediate II; dissolve 13.2 mmol of cyclopentadienyldimethylchlorosilane (Ref. Eur. J. Inorg. Chem. 2010, 1133–1142) in 20 mL of anhydrous THF, and gradually add it dropwise to the lithium salt solution of Intermediate II at -78 °C (it becomes a dark red suspension), slowly raise the temperature to 25 °C and stir for 15 h; after the reaction is completed, add 80 mL of water to the reaction solution at 0 °C, let it stand for liquid separation, collect the organic phase, extract the aqueous phase with dichloromethane (50 mL × 3), mix all the organic phases, and dry them with anhydrous MgSO 4 dry, filter, and remove the solvent from the filtrate by rotary evaporation to obtain a yellow solid product. The yellow solid product is further purified by washing with EtOH (100 mL × 3) to obtain a yellow solid powder, which is the Cat.4 ligand with a yield of 88%.

[0152] 1 H NMR (500 MHz, Chloroform-d) δ 7.85 (d, J = 7.9 Hz, 1H), 7.81–7.75 (m, 1H), 7.55 (dt, J = 4.5, 1.9 Hz, 2H), 7.53 (s, 1H), 7.55–7.44 (m, 10H), 7.43–7.36 (m, 2H), 6.88–6.81 (m, 4H), 6.51–6.45 (m, 1H), 6.20 (dd, J = 10.9, 6.1 Hz, 1H), 6.16–6.05 (m, 5H), 5.98 (ddt, J = 2.6, 1.9, 1.1 Hz, 1H), 3.51–3.45 (m, 1H), 2.62–2.50 (m, 2H), 0.09 (t, J = 1.5 Hz, 6H), 0.02 (t, J = 1.5 Hz, 6H).

[0153] (2) Preparation of Cat.4 Complex: Under N 2Under an inert atmosphere, 5 mmol of the Cat.4 ligand was dissolved in 100 mL of diethyl ether in a 200 mL Schlenk flask. At 0 °C, 21 mmol of n-BuLi (1.6 M hexane solution) was added dropwise to the reaction solution, and then the temperature was slowly raised to 25 °C and reacted for 18 h. After filtration and drying, a light yellow solid (lithium salt of the Cat.4 ligand) was obtained; the lithium salt of the Cat.4 ligand and 10 mmol of ZrCl 4 were successively added to a 200 mL Schlenk flask, and then 130 mL of toluene was added. After reacting at 25 °C for 30 h, the resulting orange-yellow suspension was filtered, and then the residue was washed with toluene (30 mL × 3). The filtrate was collected, concentrated, and precipitated at -18 °C to obtain an orange-yellow solid powder, which was the Cat.4 complex with a yield of 62%.

[0154] 1 H NMR (400 MHz, C 6 D 6 ): δ 7.48 - 7.38 (m, 4H), 7.32 (m, 4H), 7.28 - 7.22 (m, 2H), 7.18 (d, J = 7.4 Hz, 2H), 7.10 (t, J = 7.1 Hz, 2H), 6.70 (m, 2H), 6.50 (d, J = 3.1 Hz, 2H), 5.80 - 5.67 (m, 4H), 5.55 - 5.40 (m, 4H), 1.57 (m, 6H), 1.43 (m, 6H).

[0155] Example 5 Preparation of the Cat.5 Complex

[0156]

[0157] The synthetic route of Cat.5 is as follows:

[0158]

[0159] (1) Preparation of the Cat.5 Ligand: In N 2Under an inert atmosphere, 6 mmol of Intermediate II was dissolved in 100 mL of anhydrous THF in a 200 mL Schlenk flask and placed in an ice-water bath. 12 mmol of n-BuLi (1.6 M hexane solution) was added dropwise to the above reaction solution at 0 °C (the color of the solution gradually changed from colorless to dark red), and then the reaction was carried out at 25 °C for 3 h to obtain a solution of the lithium salt of Intermediate II. 13.2 mmol of cyclopentadienylphenylchlorosilane (Ref. J. Chem. Soc., Dalton Trans., 2001, 1131–1136) was dissolved in 30 mL of anhydrous THF and added dropwise to the solution of the lithium salt of Intermediate II at -78 °C (it became a dark red suspension), and then slowly warmed to 25 °C and stirred for 15 h. After the reaction was completed, 80 mL of water was added to the reaction solution at 0 °C. After standing and separating layers, the organic phase was collected, and the aqueous phase was extracted with dichloromethane (50 mL × 3). After mixing all the organic phases, they were dried over anhydrous MgSO 4 After drying and filtration, the solvent in the filtrate was removed by rotary evaporation to obtain a yellow solid product. The yellow solid product was further purified by washing with EtOH (100 mL × 3) to obtain a yellow solid powder, which was the Cat.5 ligand with a yield of 85%.

[0160] 1 H NMR (500 MHz, Chloroform-d) δ 7.84 (d, J = 7.4 Hz, 1H), 7.78 (dd, J = 7.6, 1.5 Hz, 1H), 7.60–7.44 (m, 13H), 7.42–7.30 (m, 9H), 7.30–7.23 (m, 4H), 6.87–6.80 (m, 4H), 6.53–6.47 (m, 1H), 6.36 (dt, J = 2.4, 1.3 Hz, 1H), 6.24 (dd, J = 10.9, 6.1 Hz, 1H), 6.20–6.09 (m, 4H), 5.25–5.19 (m, 1H), 2.84 (dddt, J = 22.1, 8.4, 7.1, 1.5 Hz, 2H), 0.62 (t, J = 1.5 Hz, 3H), 0.55 (t, J = 1.5 Hz, 3H).

[0161] (2) Preparation of Cat.5 complex: Under an N 2 Under an inert atmosphere, 5 mmol of the Cat.5 ligand was dissolved in 100 mL of diethyl ether in a 200 mL Schlenk flask. 21 mmol of n-BuLi (1.6 M hexane solution) was added dropwise to the reaction solution at 0 °C, and then slowly warmed to 25 °C and reacted for 18 h. After filtration and drying, a light yellow solid (lithium salt of the Cat.5 ligand) was obtained. The lithium salt of the Cat.5 ligand and 10 mmol of ZrCl 4Add them successively into a 200 mL Schlenk flask, then add 130 mL of toluene. After reacting at 25 °C for 30 h, filter the resulting orange-yellow suspension, then wash the residue with toluene (30 mL × 3), collect the filtrate, concentrate it, and precipitate it at -18 °C to obtain an orange-yellow solid powder, which is the Cat.5 complex with a yield of 69%.

[0162] 1 H NMR(400MHz,C 6 D 6 ):δ7.79 - 7.67(m,4H),7.60(m,4H),7.45 - 7.25(m,4H),7.22(d,J=7.3Hz,2H),7.18 - 7.08(m,10H),7.05(d,J=3.2Hz,2H),6.95(m,2H),6.81(d,J=3.0Hz,2H),6.50 - 6.41(m,4H),6.20 - 5.95(m,4H),1.48(s,3H),1.26(s,3H).

[0163] Example 6 Preparation of Cat.6 Complex

[0164]

[0165] The synthetic route of Cat.6 is as follows:

[0166]

[0167] (1) Preparation of Cat.6 ligand: Under a N 2 atmosphere, in a 200 mL Schlenk flask, dissolve 6 mmol of intermediate II in 100 mL of anhydrous THF and place it in an ice-water bath; slowly add 12 mmol of n-BuLi (1.6 M hexane solution) dropwise to the above reaction solution at 0 °C (the color of the solution gradually changes from colorless to dark red), then react at 25 °C for 3 h to obtain a lithium salt solution of intermediate II; dissolve 13.2 mmol of cyclopentadienyldiphenylchlorosilane (Ref. Eur. J. Inorg. Chem. 2010, 1133–1142) in 20 mL of anhydrous THF and slowly add it dropwise to the lithium salt solution of intermediate II at -78 °C (it becomes a dark red suspension), and slowly warm up to 25 °C and stir for 15 h; after the reaction is completed, add 80 mL of water to the reaction solution at 0 °C, let it stand for liquid separation, collect the organic phase, extract the aqueous phase with dichloromethane (50 mL × 3), mix all the organic phases, and use anhydrous MgSO 4After drying and filtration, the solvent in the filtrate was removed by rotary evaporation to obtain a yellow solid product. The yellow solid product was further washed and purified with EtOH (100 mL×3) to obtain a pale yellow solid powder, which was the Cat.6 ligand with a yield of 81%.

[0168] 1 H NMR (500 MHz, Chloroform-d) δ 7.82 (d, J = 7.4 Hz, 1H), 7.80–7.75 (m, 1H), 7.58 (dd, J = 7.4, 1.6 Hz, 1H), 7.59–7.50 (m, 3H), 7.53–7.45 (m, 9H), 7.45 (dd, J = 7.5, 1.5 Hz, 1H), 7.41–7.30 (m, 18H), 7.31 (d, J = 6.6 Hz, 4H), 6.92–6.84 (m, 2H), 6.69 (s, 1H), 6.56–6.50 (m, 1H), 6.28 (dd, J = 11.0, 6.2 Hz, 1H), 6.24–6.16 (m, 3H), 6.20–6.13 (m, 3H), 5.51 (dd, J = 5.9, 1.0 Hz, 1H), 4.84–4.77 (m, 2H).

[0169] (2) Preparation of Cat.6 complex: Under N 2 atmosphere, in a 200 mL Schlenk flask, 5 mmol of the Cat.6 ligand was dissolved in 100 mL of diethyl ether. At 0 °C, 21 mmol of n-BuLi (1.6 M hexane solution) was added dropwise to the reaction solution, and then the temperature was slowly raised to 25 °C and reacted for 18 h. After filtration and drying, a yellow solid (lithium salt of the Cat.6 ligand) was obtained; the lithium salt of the Cat.6 ligand and 10 mmol of ZrCl 4 were successively added to a 200 mL Schlenk flask, then 130 mL of toluene was added, and after reacting at 25 °C for 30 h, the resulting orange-red suspension was filtered, and then the residue was washed with toluene (30 mL×3). The filtrate was collected, concentrated and precipitated at -18 °C to obtain an orange-red solid powder, which was the Cat.6 complex with a yield of 60%.

[0170] 1 H NMR (400 MHz, C 6 D 6): δ 7.60 - 7.49 (m, 4H), 7.45 - 7.39 (m, 4H), 7.33 (m, 10H), 7.26 (d, J = 7.2 Hz, 2H), 7.21 (t, J = 7.0 Hz, 2H), 7.18 - 7.05 (m, 10H), 6.98 (dd, J = 7.5 Hz, 3.1 Hz, 2H), 6.92 (m, 4H), 6.86 (d, J = 3.1 Hz, 2H), 6.70 - 6.53 (m, 4H), 6.24 - 6.12 (m, 4H).

[0171] Example 7 Copolymerization of Ethylene and Norbornene Catalyzed by the Complex

[0172] A 250 mL stainless steel reactor equipped with a magnetic stirrer was dried at 100 °C for more than 2 h, evacuated to ~2.5 mbar while still hot, and then purged with N 2 and vacuum - N 2 for three times, and then purged with vacuum - ethylene gas for three times. While maintaining a slightly positive pressure inside the reactor and a stirring speed of 500 rpm, 100 mL of a 3 M norbornene / toluene solution and 1.7 mL of a MAO toluene solution (1.5 M) were successively added to the reactor. Then the reaction temperature was raised to 130 °C, and the pressure inside the reactor (polymerization reaction pressure) was maintained at 0.4 MPa by ethylene gas. After the reaction system was stabilized, 5.0 mL (0.001 M) of the complex toluene solution was pressured into the reaction system through ethylene gas to start the polymerization reaction. After 2 min of the polymerization reaction, the ethylene gas supply was stopped. After the reactor was cooled to 100 °C, the unreacted ethylene was depressurized and discharged, and the reaction solution was drained into 500 mL of ethanol. The polymerization product was washed three times with ethanol and then dried to a constant weight in a vacuum oven at 50 °C. The polymerization reaction activity and copolymer characterization results are shown in Table 1.

[0173] Example 8 Copolymerization of Propylene and Norbornene Catalyzed by the Complex

[0174] A 250 mL stainless steel reactor equipped with a magnetic stirrer was dried at 100 °C for more than 2 h, evacuated to ~2.5 mbar while still hot, and then purged with N 2 and vacuum - N 2Replace 3 times, and then replace with vacuum-propylene gas 3 times. Keeping the reactor under slight positive pressure and stirring speed of 500rpm, add 100mL 3M norbornene / toluene solution and 1.7mL MAO toluene solution (1.5M) into the reactor in turn, then raise the reaction temperature to 130℃, maintain the pressure in the reactor (polymerization reaction pressure) at 0.4MPa by propylene gas, and after the reaction system is stable, press 5.0mL (0.001M) of the complex toluene solution into the reaction system by propylene gas to start the polymerization reaction. After 3min of polymerization reaction, stop passing propylene gas, cool the reactor to 100℃, release the pressure to discharge unreacted propylene, and discharge the reaction liquid into 500mL ethanol. Wash the polymerization product with ethanol 3 times, and dry it in a vacuum oven at 50℃ to constant weight. The polymerization activity and copolymer characterization results are shown in Table 2.

[0175] Comparative Example 1rac-SiMe 2 (Ind) 2 ZrCl 2 Copolymerization of Ethylene and Norbornene Catalyzed by Complex

[0176] A 250 mL stainless steel reactor equipped with a magnetic stirrer was dried at 100 °C for more than 2 h, evacuated to ~2.5 mbar while hot, and then N 2 And vacuum-N 2 Replace 3 times, and then replace with vacuum-ethylene gas 3 times. Keep the reactor slightly positive pressure and stirring speed at 500rpm, add 100mL 3M norbornene / toluene solution and 1.7mL MAO toluene solution (1.5M) into the reactor in turn, then raise the reaction temperature to 130°C, and maintain the pressure in the reactor (polymerization reaction pressure) at 0.4MPa by ethylene gas. After the reaction system is stable, rac-SiMe 2 (Ind) 2 ZrCl 2 5.0 mL (0.001 M) of the complex toluene solution was pressed into the reaction system to start the polymerization reaction. After 2 minutes of polymerization, the ethylene gas was stopped, the reactor was cooled to 100°C, the pressure was released to discharge the unreacted ethylene, and the reaction liquid was discharged into 500 mL of ethanol. The polymer product was washed with ethanol three times and then dried in a vacuum oven at 50°C to constant weight. The polymerization activity and copolymer characterization results are shown in Table 1.

[0177] Comparative Example 2rac-SiMe 2 (Ind) 2 ZrCl 2 Copolymerization of Propylene and Norbornene Catalyzed by Complex

[0178] A 250 mL stainless steel reactor equipped with a magnetic stir bar was dried at 100 °C for more than 2 h, evacuated to ~2.5 mbar while still hot, and then purged with N 2 and vacuum-N 2 was replaced three times, and then vacuum-propylene gas was replaced three times. While maintaining a slightly positive pressure inside the reactor and a stirring speed of 500 rpm, 100 mL of a 3 M norbornene / toluene solution and 1.7 mL of MAO (1.5 M toluene solution) were sequentially added to the reactor. Then, the reaction temperature was raised to 130 °C, and the pressure inside the reactor (polymerization reaction pressure) was maintained at 0.4 MPa by propylene gas. After the reaction system was stable, rac-SiMe 2 (Ind) 2 ZrCl 2 A 5.0 mL (0.001 M) toluene solution of the complex was pressured into the reaction system to start the polymerization reaction. After 3 min of the polymerization reaction, the propylene gas supply was stopped. After the reactor was cooled to 100 °C, the unreacted propylene was depressurized and discharged, and the reaction solution was drained into 500 mL of ethanol. The polymerization product was washed three times with ethanol and then dried in a vacuum oven at 50 °C to a constant weight. The results of the polymerization reaction activity and copolymer characterization are shown in Table 2.

[0179] Table 1 Results of ethylene and norbornene copolymerization reaction activity and copolymer characterization

[0180]

[0181] Table 2 Results of propylene and norbornene copolymerization reaction activity and copolymer characterization

[0182]

[0183] Table 3 Results of copolymer mechanical property characterization

[0184]

[0185] The results in Table 1 show that the dual-active-site metallocene complex described in the present invention has excellent catalytic activity for copolymerization of ethylene and norbornene, a high cycloolefin monomer insertion rate, and a large molecular weight distribution regulation range.

[0186] The results in Table 2 show that the dual-active-site metallocene complex described in the present invention has excellent catalytic activity for copolymerization of propylene and norbornene, a high cycloolefin monomer insertion rate, and a large molecular weight distribution regulation range.

[0187] The results in Table 3 show that the polymer prepared by the method described in the present invention has excellent toughness while maintaining high mechanical strength.

[0188] In addition, the metallocene complex with dual active centers according to the present invention also has excellent high-temperature stability, and can still maintain high polymerization activity and comonomer insertion rate at a high reaction temperature of 130°C. The obtained polymerization product has a relatively wide molecular weight distribution and can be regulated by adjusting the catalyst structure, and it is possible to prepare a bimodal COC polymer with a single catalyst (such as Figure 1 shown), and the polymerization process is simple.

[0189] Unless otherwise specified, the terms used in the present invention have the meanings commonly understood by those skilled in the art.

[0190] The embodiments described in the present invention are for illustrative purposes only and are not intended to limit the scope of protection of the present invention. Those skilled in the art can make various other substitutions, changes, and improvements within the scope of the present invention. Therefore, the present invention is not limited to the above embodiments, but is only defined by the claims.

Claims

1. A metallocene complex with two active centers having the structure shown in formula (Ⅰ), wherein, M is selected from titanium, zirconium or hafnium; Cp 1 , Cp 2 and Cp 3 are each independently selected from substituted or unsubstituted cyclopentadienyl, indenyl or fluorenyl; A is selected from a carbon atom or a silicon atom; R 1 and R 2 each independently selected from hydrogen, a substituted or unsubstituted C1-C20 alkyl group, a C3-C20 cycloalkyl group, a C6-C20 aryl group, or a silyl group containing 1 to 3 Si atoms; X is selected from halogen, -NH 2 , substituted or unsubstituted C1-C20 alkyl, -N(C1-C20 alkyl) 2 , C6-C20 aryl or benzyl; When the above groups are substituted groups, the number of substituents is 1, 2, 3 or 4, and each is independently selected from halogen, C1-C10 alkyl, C1-C10 alkoxy, C3-C10 cycloalkyl, C6-C20 aryl or benzyl.

2. The metallocene complex with two active centers according to claim 1, characterized in that, The R 1 and R 2 are each independently selected from hydrogen, C1-C6 alkyl, C3-C8 cycloalkyl or C6-C12 aryl; preferably, the R 1 and R 2 are each independently selected from hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl or phenyl; and / or, X is selected from halogen, C1-C4 alkyl or -NH 2 ; preferably, X is selected from Cl.

3. The metallocene complex with two active centers according to claim 1 or 2, characterized in that, The Cp 1 and Cp 2 are selected from substituted or unsubstituted indenyl or fluorenyl, and the Cp 3 is selected from substituted or unsubstituted cyclopentadienyl. When the Cp 1 and / or Cp 2 and / or Cp 3 is a substituted group, the number of substituents is 1 or 2, and each is independently selected from halogen, C1-C6 alkyl, C1-C6 alkoxy, C3-C8 cycloalkyl, C6-C12 aryl or benzyl; preferably, the substituents are selected from C1-C4 alkyl, C3-C6 cycloalkyl, phenyl, naphthyl, biphenyl or benzyl.

4. The metallocene complex with two active centers according to any one of claims 1-3, characterized in that, The metallocene complex with two active centers is selected from any one of the following complexes Cat.1 to Cat.6: Cat.1 Cat.2 Cat.3 Cat.4 Cat.5 Cat.6 5. A preparation method of the metallocene complex with two active centers according to any one of claims 1-4, comprising the following steps: S1: Dissolve 2-bromo-2'-iodobiphenyl in a solvent, then add alkyllithium for lithiation at low temperature, then add trimethyl borate for reaction, and then add an aqueous hydrochloric acid solution for hydrolysis to obtain compound 2'-bromo-1,1'-biphenyl-2-boronic acid, denoted as compound A; S2: React compound A with the halide of Cp 1 under alkaline conditions through a Suzuki coupling reaction catalyzed by a palladium catalyst to obtain compound B; S3: React compound B with boric acid or Cp substituted with a borate group 2 to obtain intermediate II through a Suzuki coupling reaction catalyzed by a palladium catalyst under alkaline conditions; S4: React the intermediate II with an organometallic reagent to obtain a metal salt of the intermediate II, and then carry out an addition reaction with compound III. After the reaction is completed, quench with water or a saturated NH 4 Cl solution; alternatively, carry out a substitution reaction of the metal salt of the intermediate II with compound IV to obtain a ligand compound; S5: React the ligand compound described in S4 with an alkyl metal reagent to obtain a metal salt of the ligand compound, and then react it with MX 4 or its ether complex to obtain the bis-active center metallocene complex; 6. The method according to claim 5, characterized in that, In the formula (Ⅳ), X1 is selected from halogen, preferably Cl; in step S1, the alkyllithium is one or more of C1-C6 alkyllithiums, preferably one or more of methyllithium, n-butyllithium, n-hexyllithium; in step S3, the boronic acid compound of Cp2 is selected from 6-indene boronic acid, 5-indene boronic acid, 2-fluorene boronic acid, 6-indene boronic acid pinacol ester, 5-indene boronic acid pinacol ester, 2-fluorene boronic acid pinacol ester; in step S4, the compound III is selected from 6,6-dimethylfulvene, 6,6-diphenylfulvene, 6-methyl-6-phenylfulvene; in step S4, the compound IV is selected from dimethylcyclopentadienylchlorosilane, cyclopentadienyldiphenylchlorosilane, methylcyclopentadienylphenylchlorosilane.

7. Use of the metallocene complex with two active centers according to any one of claims 1-4 as an olefin polymerization catalyst, characterized in that, The olefin polymerization is a copolymerization of ethylene and / or α-olefin with cycloolefin; Preferably, the α-olefin is an α-olefin of C3-C12, preferably selected from one or more of 1-propene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, and the cycloolefin is a cycloolefin of C6-C21, preferably selected from one or more of cyclohexene, norbornene, tetracyclododecene.

8. An olefin polymerization method, comprising the following steps, in the presence of a main catalyst and a cocatalyst, ethylene and / or α-olefin and cycloolefin are polymerized to form an olefin copolymer; wherein, The main catalyst is the metallocene complex with two active centers according to any one of claims 1-4; Preferably, the α-olefin is an α-olefin having 3 to 12 carbon atoms, preferably selected from one or more of 1-propene, 1-butene, 1-pentene, 1-hexene, 1-heptene, and 1-octene, and the cycloolefin is a cycloolefin having 6 to 21 carbon atoms, preferably selected from one or more of cyclohexene, norbornene, and tetracyclododecene.

9. The olefin polymerization method according to claim 8, characterized in that the molar ratio of the main catalyst to the cocatalyst is 1:1 to 5000, preferably 1:1 to 1500; and / or, the cocatalyst is selected from one or more of alkylaluminum, alkylaluminum chloride, aluminoxane, and boron-containing additives; preferably, the alkylaluminum is selected from one or more of trimethylaluminum, triethylaluminum, triisobutylaluminum, and tri-n-hexylaluminum, and the alkylaluminum chloride is selected from one or more of diethylaluminum monochloride, diethylaluminum dichloride, and sesqui-diethylaluminum monochloride; the aluminoxane is selected from one or more of methylaluminoxane, ethylaluminoxane, and isobutylaluminoxane; the boron-containing additive is selected from one or two of tris(pentafluorophenyl)borane and triphenylcarbenium tetrakis(pentafluorophenyl)borate; More preferably, the cocatalyst is selected from methylaluminoxane or a combination of methylaluminoxane and triisobutylaluminum in a molar ratio of 1 to 50:1 (preferably 2 to 30:1).

10. The olefin polymerization method according to claim 8 or 9, characterized in that the reaction temperature of the polymerization reaction is 50 to 200 °C, preferably 90 to 180 °C; and / or, the reaction pressure of the polymerization reaction is 0.01 to 10 MPa, preferably 0.1 to 3 MPa; and / or, the reaction time of the polymerization reaction is 0.1 to 1000 min, preferably 1 to 100 min.

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