Flexible mononuclear arylmethyl alpha-diimine palladium (II) catalysts and their use in the catalytic polymerization of ethylene

Abstract

The application discloses a flexible mono-arylmethyl alpha-diimine palladium (II) catalyst and application thereof in catalytic polymerization of ethylene. The catalyst has 1,2-acenaphthene and 2,3-butanedione as a core skeleton, and successfully realizes high branching degree and wide molecular weight adjustment of polyethylene by skillfully introducing a flexible mono-arylmethyl structure. The catalyst has significant polymerization activity, which is between 1.6 and 15.1*10 4 g / (mol Pd·h). Compared with traditional rigid ortho-aryl and ortho-di-arylmethyl Pd(II) catalysts, the flexible catalyst can significantly improve the branching density, and provides a highly flexible means for adjusting the viscosity of PAO lubricating oil base oil. In the copolymerization reaction of ethylene and methacrylic acid, the flexible catalyst also exhibits excellent performance, which is superior to rigid counterparts in promoting MA insertion, and further verifies the broad application prospect of the flexible catalyst in synthesis of polar functionalized polyethylene.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of metal catalysis and olefin polymerization, and particularly relates to a flexible mono-arylmethyl alpha-diimine palladium (II) catalyst and its application in catalytic polymerization of ethylene. BACKGROUND

[0002] Hyperbranched polyethylene (HBPE) is a unique polyethylene characterized by a highly branched structure, which can improve solubility, reactivity and other physical properties, making it suitable for use in coatings, adhesives and viscosity modifiers. On the other hand, polar functionalized polyethylene (PFPE) is a chemically modified polyethylene that incorporates polar groups, improving compatibility, adhesion, wetting and other surface properties, and due to its biocompatibility, it can be applied in compatibilizers, coating additives and medical devices.

[0003] Both HBPE and PFPE exhibit special properties that are different from traditional polyethylene. Currently, great progress has been made in the field of post-transition metal catalytic systems for the copolymerization of ethylene with polar monomers and the synthesis of HBPE. In addition, some important progress has been made in the synthesis of HBPE. Among them, alpha-diimine palladium catalysts have inherent advantages in the synthesis of HBPE, especially in the production of polar functionalized HBPE, and currently there is no other viable catalytic system that can replace it. In this study, we introduce a new flexible mono-arylmethyl alpha-diimine palladium catalyst specifically for the preparation of HBPE. SUMMARY

[0004] In order to overcome the problem of low activity and low branching density of the polymer obtained by the polymerization of hyperbranched polyethylene and polar functionalized polyethylene catalysts in the prior art, the present application provides a flexible mono-arylmethyl alpha-diimine palladium (II) catalyst and its application in catalytic polymerization of ethylene.

[0005] The flexible mono-arylmethyl alpha-diimine palladium (II) catalyst of the present application has the following general structure:

[0006]

[0007] wherein: R is selected from methyl or naphthyl; X1 = Cl; X2 = CH3, Et, n-Pr or n-Bu; R1, R2, R3 are independently selected from H, Me, Et, tBu, F, Cl, Br, OMe or CF3.

[0008] The flexible mono-arylmethyl alpha-diimine palladium (II) catalyst of the present application further has the following structure:

[0009]

[0010] The synthetic route of the flexible mono-arylmethyl α-diimine palladium (II) catalyst of the present application is shown as follows:

[0011]

[0012] Specifically comprising the following steps:

[0013] Step 1: Preparation of flexible mono-arylmethyl aniline compound

[0014] Zinc powder was placed in a Schlenk tube, and then anhydrous LiCl and dry oxygen-free THF were added in the controlled environment of a glove box. The Schlenk tube was taken out of the glove box, and the zinc was activated using 1,2-dibromomethane and TMSCl. Subsequently, arylbenzobromide was introduced at ambient temperature, and the reaction mixture was heated to 50°C and kept overnight. After that, the zinc crown acyl was separated from the zinc powder through a syringe filter, and was reserved as a THF solution for subsequent reactions. In a separate Schlenk tube, 2,6-dibromoaniline, 2-dicyclohexylphosphino-2',6'-dimethoxybiphenyl and Pd(OAc)2 were combined and degassed. THF was added, the mixture was stirred until the color was observed to change to red, the first step solution in THF was added dropwise, and the reaction mixture was stirred at room temperature for 2 hours before being quenched with saturated NH4Cl aqueous solution. The product was then extracted using diethyl ether (3 x 50 mL). The combined organic extracts were washed with aqueous thiourea solution and dried over MgSO4, and after removal of the solvent and purification by flash column chromatography (PE:EA = 10:1), the flexible mono-arylmethyl aniline compound was obtained as a white solid.

[0015] Step 2: Preparation of catalyst ligand

[0016] 2a, A solution of the flexible mono-arylmethyl aniline compound, 1,2-acenaphthenequinone and acetic acid was dissolved in acetonitrile, and the mixture was continuously stirred at 80°C for 48 hours. During the reaction, samples were periodically collected every 6 hours and monitored on TLC plates. This process continued until an obvious spot appeared on the TLC plate, indicating that the reaction was complete. Subsequently, the solvent was evaporated, and concentrated to 10 mL under vacuum, and the resulting concentrated solution was diluted in methanol (100 mL) to form a yellow solid precipitate. After filtering and separating the solid, the catalyst ligand L1 or L3 was obtained as a yellow solid powder by vacuum drying.

[0017] wherein the molar ratio of the flexible mono-arylmethyl aniline compound to 1,2-acenaphthenequinone is 2:0.9.

[0018] 2b, the solution of flexible mono-arylmethyl aniline compound, 2,3-butanedione and acetic acid was dissolved in ethanol and stirred for 48 hours under the same conditions. During the reaction, samples were collected regularly every 6 hours and monitored on TLC plate. This process continued until a clear spot appeared on the TLC plate, indicating the completion of the reaction. Subsequently, the solvent was evaporated and concentrated to 10 mL under vacuum, and the resulting concentrated solution was diluted in methanol (100 mL) to form a yellow solid precipitate. After filtering and separating the solid, the catalyst ligand L2 or L4 was obtained as a yellow solid powder by vacuum drying.

[0019] wherein the molar ratio of flexible mono-arylmethyl aniline compound to 2,3-butanedione is 2:0.9.

[0020] Step 3: Preparation of catalyst

[0021] The catalyst ligand obtained in step 2 was mixed with (COD)PdMeCl in dichloromethane under nitrogen protection, and stirred at room temperature for 12 hours. After filtering the suspension, the mother liquor was subjected to solvent removal under vacuum, washed with diethyl ether, and vacuum dried to obtain a yellow powder solid complex.

[0022] The preparation method of (COD)PdMeCl is as follows: dissolve palladium chloride in concentrated hydrochloric acid, add ethanol, and inject 1,4-cyclooctadiene (COD). The system turns yellow, and a yellow solid is obtained by filtration. The yellow solid is reacted with dichloromethane and tetramethyl tin at room temperature until the yellow color disappears. After filtration, the filtrate is extracted to a certain volume, dichloromethane is added to precipitate a white solid, which is washed with diethyl ether and the solvent is removed to obtain a white solid powder (COD)PdMeCl.

[0023] In step 1, the molar ratio of Zn powder, LiCl, 1,2-dibromomethane, TMSCl and arylbenzobromide is 1.4:1:0.05:0.01:1, and the molar ratio of 2,6-dibromoaniline, Sphos, Pd(OAc)2 and zinc oxide solution containing zinc is 1:0.02:0.01:2.4. The developing agent used for column chromatography purification is petroleum ether: ethyl acetate = 10:1.

[0024] The flexible mono-arylmethyl α-diimine palladium (II) catalyst of the present application has 1,2-acenaphthene or 2,3-butanedione as the catalyst skeleton, and introduces a flexible mono-arylmethyl group on the skeleton, thereby having better activity.

[0025] The application of the flexible mono-arylmethyl α-diimine palladium (II) catalyst of the present application in the preparation of high-branched polyethylene by catalyzing ethylene polymerization.

[0026] Further, the catalytic reaction system also includes sodium tetra(3,5-bis(trifluoromethyl)phenyl)borate (NaBArF).

[0027] The molar ratio of the flexible monoarylmethyl α-diimine palladium(II) catalyst to NaBArF is 1:2.

[0028] Polymerization conditions: 10.0 μmol catalyst, 2.0 eq NaBArF, 4 atm ethylene pressure.

[0029] The reaction temperature is 0-150℃, and the reaction time is 1-12 hours.

[0030] Application of highly branched polyethylene prepared by ethylene polymerization using the flexible monoarylmethyl α-diimine palladium(II) catalyst of this invention in adjusting the viscosity of poly-α-olefin base oil.

[0031] The present invention relates to the application of the flexible monoarylmethyl α-diimine palladium(II) catalyst in the copolymerization of ethylene with polar monomers.

[0032] Furthermore, the catalytic reaction system also includes sodium tetrakis(3,5-bis(trifluoromethyl)phenyl)borate (NaBArF).

[0033] The molar ratio of the flexible monoarylmethyl α-diimine palladium(II) catalyst to NaBArF is 1:2.

[0034] The polar monomer includes methyl acrylate.

[0035] Polymerization conditions: 20.0 μmol catalyst, 2.0 eq NaBArF, 1 M-2 M methyl acrylate, and 2 atm ethylene pressure.

[0036] The polymerization reaction temperature is 0-150℃, and the reaction time is 1-12 hours.

[0037]

[0038] During ethylene polymerization, these catalysts produced polyethylene with high branching degree (79-95 / 1000) and molecular weight varying between 7.7 and 144.4 kg / mol. The polymerization activity ranged from 1.6 to 15.1 × 10⁻⁶. 4 Between g / (mol Pd·h). When used with rigid o-aryl and o-diarylmethyl Pd(II) catalysts ( Figure 1 When juxtaposed, the flexible catalyst of this invention significantly increases the branching density (94: 28-34 / 1000). These highly branched polyethylenes can effectively regulate the viscosity of PAO lubricating oil base oils. A similar trend has been observed in the copolymerization of ethylene and MA. Furthermore, the flexible Pd(II) catalyst of this invention exhibits superior efficiency in promoting MA insertion during the copolymerization of ethylene and MA, compared to its rigid analogues.

[0039] Experiments have shown that in the polymerization of ethylene, when the reaction temperature is controlled between 10 and 70 °C and the reaction time is between 1 and 12 h, the Pd2 and Pd4 complexes based on diacetone exhibit high catalytic activity during homopolymerization, reaching 10. 5 g / (mol Pd·h) was used to produce high molecular weight (Mn up to 144 kg / mol) and highly branched polyethylene (BD = 84-95 / 1000C). Conversely, Pd1 and Pd3 catalysts based on acenaphthenequinone showed a yield of 10 g / (mol Pd·h). 4 With moderate activity at g / (mol Pd·h), it produces polyethylene with moderate molecular weight (up to 15 kg / mol Mn) and similar branched structure (79-120 / 1000°C) under given polymerization conditions. Notably, the catalytic activity and branching density of polyethylene both increase with increasing temperature, while its molecular weight decreases. However, it is worth mentioning that the branching density only increases slightly, mainly due to the inherently high chain walk rate and chain growth rate of the α-diimine palladium catalyst system. For catalysts Pd1-Pd4, the framework structure plays a crucial role in ethylene polymerization. Under specified experimental conditions, the butyl-supported catalysts Pd2 and Pd4 exhibit significantly higher activity (4-10 times) than their acenaphthenic counterparts Pd1 and Pd3. This enhanced activity translates into the production of polyethylene with a molecular weight 4-10 times higher. However, it is noteworthy that the framework structure has little effect on the branching density of the produced polyethylene, indicating that tuning this aspect is challenging. Furthermore, the introduction of different monoaryl methyl substituents also affects the polymerization process. Under similar polymerization conditions, phenyl palladium catalysts, such as Pd1 and Pd2, consistently produced polyethylene with higher branching densities than naphthyl palladium catalysts Pd3 and Pd4. Furthermore, the molecular weight of polyethylene was influenced by the backbone; axial phenyl substituents resulted in lower molecular weights for the acenaphthoquinone backbone and higher molecular weights for the butyl backbone. This observation may be explained by a combination of chain transfer and chain growth mechanisms specific to different backbone structures. Notably, catalysts Pd-Ph and Pd-CHPh2 efficiently produced polyethylene with significantly lower branching densities, with 28 to 34 branches per 1000 carbon atoms. Figure 2 His branching density is significantly lower than that observed in the currently used flexible monoaryl methyl catalysts Pd1-Pd4. This intriguing observation suggests that the flexible monoaryl methyl α-diimide Pd(II) system plays a crucial role in influencing the microstructure of the resulting polymer. This influence may stem from the ability of the flexible substituents to create a more accessible catalytic center environment, which could potentially promote branching. 13 C10 NMR spectroscopy analysis showed that the polyethylene produced by the flexible monoarylmethyl catalyst system was hyperbranched, containing various types of branching, mainly long-chain branching.

[0040] In copolymerization, the copolymerization of olefins and polar monomers, catalyzed by α-diimine palladium catalysts, promotes the direct synthesis of polar functionalized polyolefins. In this study, we used catalysts Pd1-Pd5 for the copolymerization of ethylene with methyl acrylate (MA). Our observations revealed relatively low catalytic activity (at a level of 10). 3 g mol -1 h -1 This yielded E-MA copolymers with low to medium molecular weights (ranging from 4.1 to 24.4 kg / mol) and medium MA incorporation ratios (1.54–5.52 mol%). Catalytic activity and copolymer molecular weight decreased with increasing initial MA concentration, while MA incorporation increased significantly. For catalysts Pd1–Pd4, the framework structure also played a crucial role in the copolymerization of ethylene and MA. Under specified experimental conditions, butyl-supported catalysts Pd2 and Pd4 exhibited poorer copolymerization ability with MA compared to acenaphthene-based analogs Pd1 and Pd3. The effect of the framework on activity and molecular weight is complex and varies at different MA concentrations, a stark contrast to its effect on ethylene homopolymerization. Notably, the branching density of the resulting copolymers is consistent with the branching strength observed in the ethylene homopolymerization reaction, and is largely unaffected by the framework type. Furthermore, the introduction of different monoaryl methyl substituents affects the copolymerization process. Phenyl palladium catalysts, including Pd1 and Pd2, exhibited excellent activity under similar polymerization conditions and produced E-MA copolymers with higher branching densities than those produced by naphthyl palladium catalysts Pd3 and Pd4. Furthermore, copolymers obtained using phenyl catalysts generally had higher molecular weights than those produced using naphthalene catalysts, a trend observed in ethylene homopolymerization. However, the insertion rate of MA was relatively insensitive to axial substituents.

[0041] Compared to ethylpalladium catalysts, the recently introduced monoarylmethyl catalysts have proven superior in homopolymerization, exhibiting higher catalytic activity and producing polyethylene with fewer branches but higher molecular weight. This improvement demonstrates that the addition of aryl groups enhances the catalyst's efficiency in chain growth while suppressing chain transfer. In copolymerization, phenylPd1 exhibits higher activity than ethylpalladium catalysts, producing E-MA copolymers with higher molecular weight, lower branching density, and lower MA insertion rate.

[0042] This invention features a uniquely designed catalyst with 1,2-acenaphthoquinone and 2,3-butanedione as its core framework. By cleverly introducing a flexible monoaryl methyl structure, it successfully achieves high branching degree (range 79-95 / 1000) and wide molecular weight adjustment (7.7 to 144.4 kg / mol) in polyethylene. Its polymerization activity is significant, ranging from 1.6 to 15.1 × 10⁻⁶. 4The results show that the flexible catalyst of this invention significantly improves the branching density (up to 94 / 1000C, compared to 28-34 / 1000C) compared to traditional rigid o-aryl and o-diarylmethyl Pd(II) catalysts, providing a highly flexible means of adjusting the viscosity of PAO lubricating oil base oils. In the copolymerization reaction of ethylene and methacrylic acid (MA), this flexible catalyst also exhibits excellent performance, not only outperforming its rigid counterparts in promoting MA insertion, but also further validating its broad application prospects in the synthesis of polar functionalized polyethylene. Attached Figure Description

[0043] Figure 1 Advantages of flexible monoarylmethyl catalysts in the synthesis of HBPE and polar functionalized HBPE.

[0044] Figure 2 Comparison of the branching density of polyethylene produced by Pd2, Pd-Ph and Pd-CHPh2 at 30℃.

[0045] Figure 3 Comparison of branching density and MA incorporation rate of polyethylene prepared from Pd2, Pd-Ph and Pd-CHPh2 at 30℃.

[0046] Figure 4 The polyethylene prepared at 30°C using the catalyst of Example 1. 1 H NMR (Table 1, entry 1).

[0047] Figure 5 The polyethylene prepared by the catalyst in Example 2 at 30°C 13 C NMR (Table 1, Entry 3).

[0048] Figure 6 The polyethylene prepared by the catalyst in Example 1 at 2M MA 13 C NMR (Table 2, Entry 2). Detailed Implementation

[0049] To better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to embodiments. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the scope of the claims of the present invention.

[0050] The synthesis steps involved in the examples are preferred catalyst synthesis steps; synthesis steps using non-preferred catalysts are not disclosed.

[0051] Reagents and raw materials used in the examples: All organometallic reactions were carried out under nitrogen protection, and all solvents were dried and deoxygenated. Anhydrous methanol and ethanol were analytical grade and used directly. Toluene was dehydrated by molecular sieves, refluxed with metallic sodium under nitrogen protection, and distilled off before use.

[0052] Example 1:

[0053] Synthesis of 1,2,6-dibenzylaniline (A1)

[0054] Zinc powder (919 mg, 14.0 mmol, 1.4 equivalence) was placed in a Schlenk tube, and anhydrous LiCl (426 mg, 10 mmol, 1.0 equivalence) and dry, oxygen-free THF (10 mL) were added under controlled conditions in a glove box. The Schlenk tube was then removed from the glove box, and the zinc was activated using 1,2-dibromomethane (93 mg, 0.5 mmol, 5 mol%) and TMSCl (10.9 mg, 0.1 mmol, 1 mol%). Subsequently, 2-benzyl bromide (10 mmol, 1.0 equivalence) was introduced at ambient temperature. The reaction mixture was then heated to 50 °C and maintained overnight. Afterward, the zinc crown acyl group was separated from the zinc powder through a syringe filter and reserved as a THF solution for subsequent reactions. In separate Schlenk tubes, 2,6-dibromoaniline (3.8 mmol, 1.0 equivalent), 2-dicyclohexylphosphine-2',6'-dimethoxybiphenyl (SPhos, 76 μmol, 2 mol%), and Pd(OAc)₂ (38 μmol, 1 mol%) were combined and degassed. THF (5 mL) was added, and the mixture was stirred until a red color was observed. The first step solution (9.2 mmol, 2.4 equivalent) was gradually added dropwise to THF. The reaction mixture was stirred at room temperature for 2 hours before quenching with a saturated aqueous NH₄Cl solution. The product was then extracted with diethyl ether (3 x 50 mL). The combined organic extracts were washed with an aqueous thiourea solution and dried over MgSO₄. Finally, the aromatic amide was separated as a white solid in 56% yield after solvent removal and purification by rapid column chromatography (PE:Et = 10:1).

[0055] The reaction route is shown below:

[0056]

[0057] NMR analysis: 1H NMR (400MHz, CDCl3) δ7.36-7.30(d,J=7.9Hz,1H,Ar-H),7.28(d,J=1.5Hz,2H,Ar-H),7.20(m,J=15.5,7.3,5.7 Hz,7H,Ar-H),7.00(d,J=7.5Hz,2H,Ar-H),6.76(t,J=7.5Hz,1H,Ar-H),3.90(s,4H,-CH2-),3.45(s,2H,-NH2). 13 C NMR (101MHz, CDCl3) δ142.94,139.32,139.32,129.43,129.43,128.77,128.61,128.60,128.60,128. 47,128.46,128.46,128.46,126.31,126.31,125.09,118.14,118.14,38.16(-CH2-),38.16(-CH2-).

[0058] 2. Synthesis of catalyst ligand (L1)

[0059] A solution of A1 (2 mmol, 2.0 equivalent), 1,2-acenaphthene (0.9 mmol, 0.9 equivalent), and acetic acid (5 mL) was dissolved in acetonitrile (10 mL). The mixture was continuously stirred at 80 °C for 48 hours. During stirring, samples were collected periodically every 6 hours and monitored on a TLC plate. This process continued until a distinct spot appeared on the TLC plate, indicating completion of the reaction. Subsequently, the solvents from both reactions were evaporated and concentrated to 10 mL under vacuum. The resulting concentrated solution was then diluted in methanol (100 mL) to form a yellow solid precipitate. After filtration, the precipitate was washed with 10 mL of ethanol and dried under vacuum to obtain a yellow solid powder (L1) in 67% yield. The reaction route is shown below:

[0060]

[0061] NMR analysis: 1 H NMR (400MHz, CDCl3) δ7.73 (d, J=8.3Hz, 2H, Ar-H), 7.23-7.01 (m, 16H, Ar-H), 6.89 (t, J=7.5Hz, 8H, Ar-H), 6.80 (t ,J=7.3Hz,4H,Ar-H),6.45(d,J=7.1Hz,2H,Ar-H),4.03(d,J=15.3Hz,4H,-CH2-),3.78(d,J=15.5Hz,4H,-CH2-). 13C NMR (101MHz, CDCl3) δ162.46 (-C=N),148.74,143.58,140.21,139.96,139.42,137.90,136.74,135.97,135.36,13 3.26,130.47,130.13,130.06,129.93,129.88,129.53,129.44,129.27,129.09,129.04,128.96,128.82,128.71, 128.59,128.58,128.35,128.13,127.95,127.73,127.69,127.40,127.19,126.41,126.30,125.55,125.08,124.2 6,124.24,124.12,124.09,123.87,123.12,122.87,122.77,122.75,122.62,37.79(-CH2-).APCI-MS(m / z):calcd forC 52 H 40 N2:693.3270,Found,693.3254,[M+H] + .

[0062] 3. Synthesis of Pd1 complexes

[0063] The Pd1 complex was synthesized by reacting (COD)PdMeCl (where COD represents 1,4-cyclooctadiene) with the corresponding ligand in dichloromethane. Under a nitrogen atmosphere, 0.2 mmol of ligand L1 was dissolved in 10 mL of dichloromethane, and then (COD)PdMeCl (0.18 mmol, 47.7 mg) was added to the solution. The resulting mixture was stirred overnight at room temperature. Most of the solvent was evaporated under reduced pressure, and the product was washed with 4 × 5 mL of diethyl ether, filtered, and dried under vacuum to give the orange-red solid product Pd1 in 72% yield. The reaction route is shown below:

[0064]

[0065] NMR analysis: 1H NMR(400MHz,CDCl3)δ7.83(t,J=8.5Hz,2H,Ar-H),7.34(t,J=7.7Hz,1H,Ar-H),7.28(d,J=1.9Hz,1H,Ar-H),7.24(d,J=2.2Hz,1H,Ar-H),7.22-7.12(m,9H,Ar-H),7.06(d,J=7.5Hz,4H,Ar-H),6.84(dt,J=11.6,7.5Hz,8H,Ar-H),6.73(q,J=7.2Hz,4H,Ar-H),6.47(d,J=7.2Hz,1H,Ar-H),6.18(d,J=7.3Hz,1H,Ar-H),4.37(d,J=15.6Hz,2H,

[0066] -CH2-),4.31-4.11(m,4H,-CH2-),4.02(d,J=15.6Hz,2H,-CH2-),0.94(s,3H,Pd-CH3). 13 C NMR(101MHz,CDCl3)δ173.19(-C=N),168.59(-C=N),143.64,143.42,142.71,142.68,139.52,139.36,138.43,132.67,132.52,132.02,131.58,131.52,131.47,131.15,130.83,130.60,130.46,130.45,130.23,130.19,129.98,129.72,129.48,129.37,128.92,128.73,128.46,128.17,128.05,127.95,127.81,127.79,127.58,127.45,127.14,126.90,126.83,126.72,126.21,125.98,125.75,125.68,124.92,124.46,124.13,124.04,38.21(-CH2-),3.24(Pd-CH3).MALDI-TOF-MS(m / z):calcd for C 52 H 40 N2Pd:798.2221,Found,798.2237,[M-Cl-Me] + .Elemental analysis:calc.for C 53 H 43ClN2Pd:C,74.91;H,5.10;N,3.30.Found:C,74.83;H,5.03;N,3.23.

[0067] Example 2:

[0068] Synthesis of 1,2,6-dibenzylaniline (A1)

[0069] The operation is the same as step 1 of Example 1.

[0070] NMR analysis: 1 H NMR (400MHz, CDCl3) δ7.36-7.30(d,J=7.9Hz,1H,Ar-H),7.28(d,J=1.5Hz,2H,Ar-H),7.20(m,J=15.5,7.3,5.7 Hz,7H,Ar-H),7.00(d,J=7.5Hz,2H,Ar-H),6.76(t,J=7.5Hz,1H,Ar-H),3.90(s,4H,-CH2-),3.45(s,2H,-NH2). 13 C NMR (101MHz, CDCl3) δ142.94,139.32,139.32,129.43,129.43,128.77,128.61,128.60,128.60,128. 47,128.46,128.46,128.46,126.31,126.31,125.09,118.14,118.14,38.16(-CH2-),38.16(-CH2-).

[0071] 2. Synthesis of catalyst ligand (L2)

[0072] A solution of A1 (2 mmol), 2,3-butanedione (0.9 mmol), and acetic acid (1 mL) was dissolved in ethanol (5 mL) and stirred for 48 hours under the same conditions. The remaining procedures were the same as in step (3) of Example 1, with a yield of 65%. The reaction route is shown below:

[0073]

[0074] NMR analysis: 1 H NMR (400MHz, CDCl3) δ7.40(d,J=1.2Hz,1H,Ar-H),7.37-7.30(m,8H,Ar-H),7.25(d,J=7.6Hz,11H,Ar-H),7.17(m,J=6.0Hz,6H,Ar-H),3.87(d,J=15.4Hz,4H,

[0075] -CH2-),3.75(d,J=15.4Hz,4H,-CH2-),1.64(s,6H,-CH3). 13 C NMR(101MHz, CDCl3)δ168.60(-C=N),147.89,140.19,128.91,128.45,128.36,128.00,125.97,123.30,37.89(-CH2-),16.15(-CH3).APCI-MS(m / z):calcd for C 44 H 40 N2:597.3270,Found,597.3248,[M+H] + .

[0076] 3. Synthesis of Pd2 complexes

[0077] Replace L1 with L2 in step 3 of Example 1, and perform the remaining operations the same as in step 3 of Example 1, achieving a yield of 85%. The reaction route is shown below:

[0078]

[0079] NMR analysis: 1 H NMR (400MHz, CDCl3) δ7.27(s,2H,Ar-H),7.25(s,4H,Ar-H),7.18(m,J=6.6Hz,18H,Ar-H),7.11(d,J=7.4Hz,2H,Ar-H),4.24(d,J= 15.7Hz,2H,-CH2-),4.18-4.03(m,4H,-CH2-),3.96(d,J=15.5Hz,2H,-CH2-),0.80(s,3H,-CH3),0.64(d,J=12.6Hz,6H,Pd-CH3). 13 C NMR (101MHz, CDCl3) δ176.54(-C=N),171.47(-C=N),143.73,143.34,139.97,138.95,131.52,130.80,129.46,129.37,129.05,12 8.73,128.66,128.48,127.08,126.56,126.50,126.23,38.30(-CH2-),38.06(-CH2-),19.38(-CH3),18.54(-CH3),2.72(Pd-CH3).

[0080] MALDI-TOF-MS(m / z):calcd for C 44 H 40N2Pd:702.2221,Found,702.2235,[M-Cl-Me] + .

[0081] Elemental analysis: calc. for C 45 H 43 ClN2Pd:C,71.71;H,5.75;N,3.72.Found:C,71.65;H,5.67;N,3.82.

[0082] Example 3:

[0083] Synthesis of 1,6-bis(naphthyl-2-ylmethyl)aniline (A2)

[0084] The 2-benzyl bromide in step 1 of Example 1 was replaced with 2-(bromomethyl)naphthalene, and the remaining operations were the same as in step 1 of Example 1, with a yield of 42%.

[0085] NMR analysis: 1 H NMR (400MHz, CDCl3) δ8.02-7.51(m,8H,Ar-H),7.49-7.22(m,6H,Ar-H),7.11(d,J=7 .5Hz,2H,Ar-H),6.84(t,J=7.5Hz,1H,Ar-H),4.09(s,4H,-CH2-),3.52(s,2H,-NH2). 13 C NMR (101MHz, CDCl3) δ143.19,137.01,136.87,133.57,133.04,132.25,130.12,129.64,128.88,128.30,127.76,127.60,127.50,127.39 ,127.32,127.24,127.16,127.10,126.77,126.66,126.58,126.10,126.02,125.43,125.09,118.28,38.44(-CH2-).ACPI-MS(m / z):calcd for C 28 H 24 N:374.1909,Found,374.1864,[M+H] + .

[0086] 2. Synthesis of catalyst ligand (L3)

[0087] Replace A1 with A2 in step 2 of Example 1, and the rest of the operation is the same as step 2 of Example 1, with a yield of 62%.

[0088] NMR analysis:1 H NMR (400MHz, CDCl3) δ7.44(d,J=8.0Hz,8H,Ar-H),7.36(d,J=8.4Hz,4H,Ar-H),7.29(d,J=8.2Hz,4H,Ar-H),7.25-7.09(m, 20H, Ar-H), 6.86 (t, J = 7.7Hz, 2H, Ar-H), 6.36 (d, J = 7.1Hz, 2H, Ar-H), 4.24 (d, J = 15.3Hz, 4H, -CH2-), 4.02 (d, J = 15.3Hz, 4H,

[0089] -CH2-). 13 C NMR (101MHz, CDCl3) δ162.68 (-C=N),148.88,139.58,137.64,133.12,131.61,128.62,128.44,128.31,128.14,127 .84,127.79,127.51,127.20,127.00,126.65,125.49,124.84,123.89,122.31,38.07(-CH2-).APCI-MS(m / z):calcd forC 68 H 48 N2:893.3896,Found,893.3865,

[0090] [M+H] + .

[0091] 3. Synthesis of Pd3 complexes

[0092] Replace L1 with L3 in step 3 of Example 1, and the rest of the operation is the same as step 3 of Example 1, with a yield of 69%.

[0093] NMR analysis: 1H NMR (400MHz, CDCl3) δ7.59(s,2H,Ar-H),7.50-7.39(m,6H,Ar-H),7.38-7.31(m,7H,Ar-H), 7.31-7.26(m,7H,Ar-H),7.24-7.00(m,14H,Ar-H),6.89(t,J=7.7Hz,1H,Ar-H),6.70(t,J=7 .7Hz,1H,Ar-H),6.43(d,J=7.1Hz,1H,Ar-H),5.98(d,J=7.2Hz,1H,Ar-H),4.66(d,J=15.7Hz ,2H,-CH2-),4.57-4.30(m,4H,-CH2-),4.25(d,J=15.4Hz,2H,-CH2-),1.01(s,3H,Pd-CH3). 13 C NMR(101MHz, CDCl3)δ173.40(-C=N),168.71(-C=N),143.83,142.87,142.50,137.22,136.19,133.08,1 32.90,132.42,131.63,131.53,131.29,129.62,129.58,129.15,129.06,128.16,128.02,127.95,127.7 5,127.66,127.60,127.53,127.19,127.13,127.07,127.03,126.91,126.77,125.77,125.58,125.12,12 4.95,124.88,123.41,123.31,38.58(-CH2-),38.09(-CH2-),3.61(Pd-CH3).MALDI-TOF-MS(m / z):calcd for C 68 H 48 N2Pd:998.2847,Found,998.2863,[M-Cl-Me] + .Elemental analysis:calc.for C 69 H 51 ClN2Pd:C,78.93;H,4.90;N,2.67.Found:C,78.76;H,4.69;N,2.61.

[0094] Example 4:

[0095] Synthesis of 1,6-bis(naphthyl-2-ylmethyl)aniline (A2)

[0096] The operation is the same as step 1 in Example 3, with a yield of 42%.

[0097] NMR analysis: 1 H NMR (400MHz, CDCl3) δ8.02-7.51(m,8H,Ar-H),7.49-7.22(m,6H,Ar-H),7.11(d,J=7 .5Hz,2H,Ar-H),6.84(t,J=7.5Hz,1H,Ar-H),4.09(s,4H,-CH2-),3.52(s,2H,-NH2). 13 C NMR (101MHz, CDCl3) δ143.19,137.01,136.87,133.57,133.04,132.25,130.12,129.64,128.88,128.30,127.76,127.60,127.50,127.39 ,127.32,127.24,127.16,127.10,126.77,126.66,126.58,126.10,126.02,125.43,125.09,118.28,38.44(-CH2-).ACPI-MS(m / z):calcd for C 28 H 24 N:374.1909,Found,374.1864,[M+H] + .

[0098] 2. Synthesis of catalyst ligand (L4)

[0099] Replace A1 with A2 in step 2 of Example 2, and the rest of the operation is the same as step 2 of Example 1, with a yield of 60%.

[0100] NMR analysis: 1 HNMR (400MHz, CDCl3) δ7.75 (dt, J=16.6, 8.7Hz, 2H, Ar-H), 7.68-7.54 (m, 11H, A r-H),7.50(s,3H,Ar-H),7.46-7.39(m,1H,Ar-H),7.37-7.29(m,7H,Ar-H),7.20 (dd,J=8.4,1.6Hz,4H,Ar-H),7.13-7.03(m,4H,Ar-H),6.99(dd,J=8.5,6.5Hz,2 H, Ar-H), 4.07 (s, 1H, -CH2-), 3.76 (q, J = 15.5Hz, 7H, -CH2-), 1.53 (s, 6H, -CH3). 13 C NMR (101MHz, CDCl3)δ

[0101] 168.56(-C=N),147.89,137.70,133.49,131.98,129.65,128.93,128.61,128.31,127.99,127.60,1 27.51,127.42,127.19,125.91,125.23,123.42,37.99(-CH2-),16.37(-CH3).APCI-MS(m / z):calcd for C 60 H 48 N2:797.3896,Found,797.3862,[M+H] + .

[0102] 3. Synthesis of Pd4 complexes

[0103] Replace L1 with L4 in step 3 of Example 1, and the rest of the operation is the same as step 3 of Example 1, with a yield of 83%.

[0104] NMR analysis: 1 H NMR (400MHz, CDCl3) δ7.75-7.57(m,16H,Ar-H),7.48(m,2H,Ar-H),7.44-7.30 (m,10H,Ar-H),7.27-7.17(m,6H,Ar-H),4.48(d,J=15.7Hz,2H,-CH2-),4.39-

[0105] 4.26(m,4H,-CH2-),4.15(d,J=15.6Hz,2H,-CH2-),0.78(s,3H,-CH3),0.56(s,3H,-CH3),0.35(s,3H,Pd-CH3). 13 C NMR(101MHz, CDCl3)δ176.30(-C=N),171.27(-C=N),143.77,143.69,143.40,137.48,136.43 ,133.42,133.38,132.03,131.53,130.79,129.21,128.95,128.44,128.25,128.03,127.67, 127.49,127.41,127.36,127.28,127.17,126.64,126.41,126.15,125.84,125.56,38.59(-C H2-),38.24(-CH2-),19.44(-CH3),18.60(-CH3),2.96(Pd-CH3).MALDI-TOF-MS(m / z):calcd for C 60 H 48N2Pd:902.2847,Found,902.2886,[M-Cl-Me] + .Elemental analysis:calc.for C 61 H 51 ClN2Pd:C,76.80;H,5.39;N,2.94.Found:C,76.67;H,5.26;N,2.78.

[0106] Example 5: Application of Pd1-Pd4 in catalytic ethylene polymerization

[0107] The general procedure for ethylene homopolymerization is as follows: First, a 350 mL thick-walled pressure glass reactor connected to a high-pressure gas line is vacuum-dried at 90 °C for at least 1 hour. Then, the reactor is adjusted to the desired polymerization temperature. Under a nitrogen atmosphere, 38 mL of CH₂Cl₂ and the required amount of NaBArF are added to the reactor, followed by the injection of the required amount of catalyst in 2 mL of CH₂Cl₂ into the polymerization system via a syringe. The reactor is pressurized under rapid stirring and maintained at 4 atm of ethylene. After the required time, the pressure reactor is vented, and the polymer is dried under vacuum overnight.

[0108] The general procedure for copolymerizing methyl acrylate (ME) with ethylene is as follows: In a typical experiment, a 350 mL thick-walled pressure glass reactor connected to a high-pressure gas line is first vacuum-dried at 90 °C for at least 1 hour. The reactor is then adjusted to the desired polymerization temperature. Under a nitrogen atmosphere, 18 mL of dichloromethane and the required amount of NaBArF are added to the reactor, followed by the injection of 2 mL of the required amounts of MA and Pd catalyst in CH2Cl2 via a syringe. The reactor is pressurized under rapid stirring and maintained at an ethylene pressure of 2 atm. After 12 hours, the pressure reactor is vented, and the copolymer is dried under vacuum overnight.

[0109] The table below shows the experimental conditions for ethylene polymerization using the preferred catalyst provided by this invention; catalyst (Cat.), temperature (T), yield (Yield), catalytic activity (Act.), polymer molecular weight (M). n Polymerization results data such as polymer molecular weight distribution (PDI) and degree of branching (brs) are available.

[0110] Table 1. Effects of catalyst and temperature on ethylene polymerization.

[0111]

[0112] a Polymerization conditions: catalyst 10.0 μmol, NaBArF = 2.0 eq, dichloromethane = 40 mL, ethylene pressure 4 atm, time = 3 hours;

[0113] b The unit of active Act is 10. 4 g mol -1 h -1 ;

[0114] c Polymer molecular weight M n The molecular weight distribution of PDI was determined by gel permeation chromatography (GPC) at 40°C in tetrahydrofuran and polystyrene standards;

[0115] d Branching degree refers to the number of branches per 1000 carbon atoms, determined by... 1 Measured by H NMR nuclear magnetic resonance method;

[0116] Table 2. Copolymerization reaction of ethylene (MA) with palladium catalyst

[0117]

[0118] a Polymerization conditions: catalyst 20.0 μmol, NaBArF = 2.0 eq, DCM + MA = 20 mL, ethylene pressure 2 atm, time = 12 hours, temperature = 30℃;

[0119] b The unit of active Act is 10. 3 g mol -1 h -1 ;

[0120] c Polymer molecular weight M n The molecular weight distribution of PDI was determined by gel permeation chromatography (GPC) at 40°C in tetrahydrofuran and polystyrene standards;

[0121] d-branching degree refers to the number of branches per 1000 carbon atoms, determined by... 1 Determined by HNMR nuclear magnetic resonance.

[0122] As shown in Table 1, a novel class of flexible monoarylmethyl α-diimide Pd(II) catalysts has been successfully designed and synthesized for the production of hyperbranched polyethylene and polar functionalized polyethylene. In ethylene polymerization, butyl-based Pd2 and Pd4 catalysts exhibited high catalytic activity (10... 5 g·mol -1 ·h -1 This process produces high-molecular-weight, highly branched polyethylene (Mn up to 144 kg / mol). In contrast, acenaphthene-derived Pd1 and Pd3 catalysts show a 10... 4 g·mol⁻¹·h -1It exhibits moderate catalytic activity, producing highly branched polyethylene with moderate molecular weight (Mn up to 15 kg / mol) under the same polymerization conditions. Furthermore, compared to previously reported rigid Pd(II) catalysts ( Figure 3 Compared to rigid catalysts, our flexible monoarylmethyl catalysts produce polyethylene with significantly more branches. The catalyst's structural framework, its axial monoarylmethyl components, and polymerization conditions play crucial roles in ethylene polymerization. Similar observations were made in the copolymerization of ethylene and MA in Table 2. Notably, these flexible monoarylmethyl catalysts, compared to rigid catalysts (…),… Figure 3 It can insert MA more effectively. 13 C10 NMR spectroscopy confirmed the hyperbranched nature of the obtained (co)polymer.

[0123] Example 6: Study on the viscosity regulating effect of HBPE in PAO base oil

[0124] In this study, polymer HBPE, a high-viscosity polyolefin liquid, showed great potential in improving the viscosity of polyalphaolefin (PAO) base oils. To explore this application, we systematically blended different masses of HBPE (Table 1, entry 4) into INEOS' PAO20 base oil to adjust its kinematic viscosity, as shown in Table 3. With increasing HBPE mass ratio, the kinematic viscosity of the resulting blends increased significantly at 40°C and 100°C, showing a positive correlation with the HBPE content. Notably, although the viscosity index decreased slightly, it remained at a high level, meeting the stringent requirements for synthetic lubricants. This experiment highlights the strong applicability of the HBPE synthesized in this study in fine-tuning the viscosity distribution of PAO lubricating oil base oils, thus demonstrating significant potential for industrial applications.

[0125] Table 3. Study on the viscosity-modifying effect of HBPE in PAO base oils.

[0126]

[0127] The foregoing has provided a detailed description of a preferred compound, complex catalyst, catalyst composition, and method for preparing an olefin polymer provided by the present invention. Specific examples have been used to illustrate the principles and implementation methods of the invention, but the invention is not limited to the specific embodiments described herein. Those skilled in the art will understand that other modifications and variations can be made without departing from the scope of the invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A flexible monoarylmethyl α-diimine palladium(II) catalyst, characterized in that... Its general structural formula is as follows: ； Where: X1=Cl; X2=CH3, Et, n-Pr or n-Bu; R1, R2, R3 are independently selected from H, Me, Et, tBu, F, Cl, Br, OMe or CF3 respectively.

2. The flexible monoarylmethyl α-diimine palladium(II) catalyst according to claim 1, characterized in that... Selected from the following structure: 。 3. The preparation method of the flexible monoarylmethyl α-diimine palladium(II) catalyst according to claim 2, characterized in that... The synthesis route is shown below: 。 4. The application of the flexible monoarylmethyl α-diimine palladium(II) catalyst according to claim 1 in the catalytic polymerization of ethylene to prepare highly branched polyethylene.

5. The application according to claim 4, characterized in that: The catalytic reaction system also includes sodium tetrakis(3,5-bis(trifluoromethyl)phenyl)borate.

6. The application according to claim 5, characterized in that: The molar ratio of the flexible monoarylmethyl α-diimine palladium(II) catalyst to sodium tetrakis(3,5-bis(trifluoromethyl)phenyl)borate is 1:

2.

7. The use of the highly branched polyethylene prepared according to claim 4, 5 or 6 in adjusting the viscosity of polyalphaolefin base oil.

8. The application of the flexible monoarylmethyl α-diimine palladium(II) catalyst according to claim 1 in the catalytic copolymerization of ethylene and polar monomers.

9. The application according to claim 8, characterized in that: The catalytic reaction system also includes sodium tetrakis(3,5-bis(trifluoromethyl)phenyl)borate and methyl acrylate to form a composite catalytic system for the reaction.

10. The application according to claim 9, characterized in that: The molar ratio of the flexible monoarylmethyl α-diimine palladium(II) catalyst to sodium tetrakis(3,5-bis(trifluoromethyl)phenyl)borate is 1:2.

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