High-thermal-stability photoresponsive alpha-diimine nickel complex, synthesis method and application thereof

Abstract

This invention provides a highly thermally stable, photoresponsive α-diimine nickel complex, its synthesis method, and its applications, aiming to develop novel olefin polymerization catalysts with both excellent thermal stability and photoresponsive properties. The core photoresponsive switch of this type of nickel complex is a rigid diphenylethylene derivative, which can achieve reversible photoisomerization of the E / Z configuration under 365 nm and 405 nm ultraviolet light irradiation: the E configuration has a relatively open coordination environment; after light irradiation, the Z configuration has a more compact spatial structure, which can form a dual regulatory mechanism: steric hindrance and potential metal-aryl π interactions. Due to this dual regulatory mechanism, the complex exhibits excellent thermal stability at 150 °C. o Even at high temperatures, it still maintains a high value of 0.8 × 10⁻⁶. 6 g·mol ‑1 ·h ‑1 The nickel complex of this invention exhibits enhanced catalytic activity and effectively inhibits chain transfer and chain walking reactions during high-temperature polymerization. By synergistically enhancing thermal stability through configurational tautomerism, and possessing both photoresponsive properties and high catalytic activity, it holds significant research value and broad application prospects in the precise synthesis of functionalized polyolefin materials.

Description

Technical Field

[0001] This invention relates to the field of catalyst technology, specifically to a method for preparing and applying a highly thermally stable photoresponsive nickel complex. Background Technology

[0002] Polyolefins, as the world's largest and most widely used polymer category, are the cornerstone of modern materials science and industry. Among them, polyethylene (PE) dominates due to its excellent mechanical strength and chemical resistance. However, traditional catalyst systems, such as Ziegler-Natta and metallocene complexes, often produce highly crystalline linear polyolefins. While these structural features endow the materials with good rigidity and tensile strength, they also result in insufficient elasticity and low flexibility, limiting their application in high-end applications. Therefore, developing novel catalytic strategies that can directly prepare polyolefin elastomers by precisely controlling the microstructure of polymer chains has become an important and challenging goal in this field.

[0003] Against this backdrop, post-transition metal catalysts have gradually demonstrated significant advantages. Compared to traditional systems, these catalysts can effectively regulate the microstructure of polyethylene, thereby reducing crystallinity and improving material elasticity, making it possible to directly synthesize polyolefin elastomers. To optimize their performance, researchers typically start with ligand design, focusing on controlling both electronic effects and steric hindrance. Introducing bulky substituents into the ligand to increase the steric hindrance of the metal center has proven to be an effective strategy for simultaneously improving the catalyst's thermal stability and the polymer's molecular weight. However, existing research has largely focused on the modification of monolayer steric hindrance, and a systematic exploration of the construction and impact of bilayer steric hindrance systems remains lacking. The research groups of Jian Zhongbao and Dai Shengyu have carried out work in this direction and published a series of results (J. Catal. 2020, 390, 30–36; Chin. J.Chem. 2021, 39, 2829–2836; Eur. Polym. J. 2022, 177 111459–111464; Polymer2022, 240, 124478–124483, Inorg. Chem. Front. 2023, 10,108–117, etc.), but the catalysts they reported still have difficulty maintaining high thermal stability or directly obtaining ideal polyolefin elastomers.

[0004] Besides ligand modification, another effective strategy is to introduce stimulus-responsive units into olefin polymerization catalysts, constructing switchable catalytic systems that can respond to external stimuli (such as acid / base, redox, ions, or light), thereby dynamically controlling the polymer topology. Light, as a clean and precise physical stimulus, has unique advantages in green synthesis. In recent years, studies have incorporated photoresponsive groups such as azobenzene and diarylethylene into olefin polymerization catalytic systems, achieving regulation of the polymerization process through photoisomerization (CCS Chem. 2020, 2, 2025–2034; Angew. Chem.Int. Ed. 2021, 60, 22195–22200; Chin. J. Chem. 2022, 40, 2919–2926; Macromolecules 2025, 58, 6570−6576, etc.). However, azobenzene compounds exhibit high energy and instability due to the strong steric entanglement between the two benzene rings in their cis configuration. Even at room temperature, the cis configuration spontaneously reverts to the more stable trans configuration. This characteristic makes it difficult for catalysts using azobenzene as the photoresponsive unit to maintain a stable cis / trans configuration ratio at high temperatures, thus hindering effective high-temperature photomodulation of polymer fine structures. In 2024, the Chen Changle and Jiang Hui research groups constructed a photoresponsive catalyst using a rigid diphenylethylene framework, successfully achieving photomodulation of ethylene polymerization (Sci. China Chem. 2024, 68, 714–722), and achieving a stable configuration at high temperatures. Unfortunately, this catalytic system exhibits relatively low activity in the polymerization of ethylene with polar monomers, thus limiting its practical application value.

[0005] Patent publication number CN119912499A discloses a type of photoresponsive mononuclear nickel / palladium complex containing a rigid diphenylethylene skeleton, its preparation method, and its applications. It incorporates weak hydrogen bonding interactions and steric hindrance into the catalyst design, achieving control over polymer molecular weight and the insertion rate of polar monomers. However, industrial production tends to use high-temperature polymerization to ensure the continuity of the polymerization process and prevent reactor fouling; therefore, the high-temperature thermal stability of the catalyst is crucial for industrial production.

[0006] Therefore, developing a novel catalyst that can remain stable under high-temperature conditions and whose polymer chain structure can be precisely controlled to directly synthesize polar polyolefin elastomers is of great scientific significance and application value. Summary of the Invention

[0007] To address the critical issues of insufficient thermal stability of existing photoresponsive catalysts at high temperatures, hindering industrial production, and poor tolerance to polar monomers, making it difficult to simultaneously increase polymer molecular weight and polar monomer insertion rate, this invention provides a novel rigid diphenylethylene photoresponsive nickel catalytic system with excellent thermal stability. Under 365 nm UV irradiation, this catalytic system can transform from the trans configuration (E) to the cis configuration (Z); and under 405 nm UV irradiation, it can transform from the cis configuration (Z) to the trans configuration (E), thereby achieving precise photocontrolled regulation of the E / Z configuration ratio. Based on the regulation of the coordination environment of the nickel center through E / Z configuration interconversion, efficient and controllable catalysis of ethylene (and its interaction with polar monomers) polymerization is achieved, resulting in polyolefin materials with ideal elastomer properties.

[0008] The proposed complex possesses both high ethylene polymerization activity and excellent thermal stability, and can catalyze the copolymerization of ethylene and polar monomers to prepare polar functionalized elastomers with an elastic recovery rate of up to 93%.

[0009] The technical solution provided by this invention is as follows:

[0010] In a first aspect, the present invention provides α-diimine nickel complexes having the chemical structures shown in formulas E-(I) and Z-(I):

[0011]

[0012] Where R 1 R is one of the following: hydrogen-substituted phenyl, phenyloxy, or phenylthio-substituted phenyl groups. 2 It is one of hydrogen, methyl, isopropyl, tert-butyl, and phenyl.

[0013] Under 365 nm ultraviolet light irradiation, the complex can change from the trans configuration (E) to the cis configuration (Z); under 405 nm ultraviolet light irradiation, it can change from the cis configuration (Z) to the trans configuration (E).

[0014] Preferably, the α-diimine nickel complex with the chemical structure shown in formula E-(I) includes at least one of E-(I)-1 to E-(I)-20, and the α-diimine nickel complex with the chemical structure shown in formula Z-(I) includes at least one of Z-(I)-1 to Z-(I)-20.

[0015]

[0016]

[0017]

[0018] In a second aspect, the present invention provides a method for synthesizing α-diimine nickel complexes having the chemical structures shown in formulas E-(I) and Z-(I), comprising:

[0019] First, E-1 / Z-1 and compound 5 undergo a Suzuki coupling reaction at 80–120 °C under the action of a first catalyst to generate a rigid diphenylethylene derivative shown in E-2 / Z-2. E-2 / Z-2 and compound 6 undergo a Suzuki coupling reaction at 80–120 °C under the action of a first catalyst to generate an aniline derivative shown in E-3 / Z-3. E-3 / Z-3 and compound 7 undergo a condensation reaction at 50–120 °C under the catalysis of a second catalyst to generate the α-diimine ligand E-4 / Z-4. Finally, E-4 / Z-4 reacts with (DME)NiBr2 at 0–60 °C to generate the α-diimine nickel complex shown in E-(Ⅰ) / Z-(Ⅰ).

[0020]

[0021]

[0022] Where R 1 R is one of the following: hydrogen-substituted phenyl, phenyloxy, or phenylthio-substituted phenyl groups. 2 It is one of hydrogen, methyl, isopropyl, tert-butyl, and phenyl;

[0023] The first catalyst is tetra(triphenylphosphine)palladium or 1,1'-bis(diphenylphosphine)ferrocene palladium(II) chloride;

[0024] The second catalyst is zinc chloride or p-toluenesulfonic acid.

[0025] Furthermore, the molar ratio of the compound shown in E-1 / Z-1 to compound 5 is (1~2):1; the molar ratio of the compound shown in E-2 / Z-2 to compound 6 is 1: (1~3); the molar ratio of the compound shown in E-3 / Z-3 to compound 7 is (2~5):1; and the molar ratio of the compound shown in E-4 / Z-4 to (DME)NiBr2 is 1:(1~5).

[0026] In the method for synthesizing α-diimine nickel complexes having the structures shown in formulas E-(I) and Z-(I) provided by the present invention, the reaction time of the α-diimine compound with (DME)NiBr2 is 2 to 48 h.

[0027] The method for the α-diimine nickel complexes shown in E-(I) and Z-(I) of the present invention involves reacting an α-diimine compound of formula E / Z-4 with (DME)NiBr2 in an organic solvent; the organic solvent is preferably dichloromethane. The molar ratio of the α-diimine compound to (DME)NiBr2 is 1:(1~5), preferably 1:(1~2); the reaction is carried out at 0 °C to 60 °C for 2~48 h, preferably 12~24 h.

[0028] This invention provides the application of the above-mentioned photoresponsive nickel complex in the field of catalytic olefin polymerization.

[0029] This invention provides a method for synthesizing polyolefin materials using a photoresponsive nickel complex as a catalyst, comprising: adding a catalytic amount of the photoresponsive nickel complex to a polymerization system as a catalyst, and carrying out a polymerization reaction at 0-200 °C. The olefin polymerization system is an ethylene-ethylene polymerization system, or an ethylene-polar monomer with a terminal double bond.

[0030] In the embodiments provided by the present invention, the polymerization reaction is carried out at a reaction temperature of 0~200 °C and a reaction pressure of 0.1~3.0 MPa for 0.05~3.0 h, and the reaction solvent is one or more of dichloromethane, n-hexane or toluene.

[0031] The embodiments provided by the present invention further include irradiating the photoresponsive nickel complex with ultraviolet light before adding a catalytic amount.

[0032] In some embodiments provided by the present invention, the wavelength of the ultraviolet light is 365 nm or 405 nm.

[0033] In some embodiments provided by this invention, the concentration of the α-diimine nickel complex E / Z-(I) in the ethylene homopolymer is 2~40 μmol·L. -1 The nickel complex was irradiated with ultraviolet light at a wavelength of 365 nm or 405 nm for 0.1 to 1.0 h, and alkylaluminum reagent was used as a co-catalyst to catalyze the polymerization reaction of ethylene to obtain polyethylene product. The polymerization reaction was carried out at a reaction temperature of 0 to 200 °C and a reaction pressure of 0.1 to 3.0 MPa for 0.05 to 3.0 h, and the reaction solvent was one or more of dichloromethane, n-hexane or toluene.

[0034] In some embodiments provided by this invention, in the copolymerization of ethylene and polar comonomers: the concentration of the α-diimine nickel complex E / Z-(I) is 200~600 μmol·L. -1The nickel complex was irradiated with ultraviolet light at a wavelength of 365 nm or 405 nm for 0.1–2.0 h, and an alkylaluminum reagent was used as a co-catalyst to catalyze the polymerization reaction of ethylene with a polar monomer containing a terminal double bond to obtain a polar polyethylene product. The polymerization reaction was carried out at a reaction temperature of 0–80 °C and a reaction pressure of 0.1–1.0 MPa for 0.05–3.0 h, the concentration of the polar monomer containing a terminal double bond was 0.05–5.0 M, and the reaction solvent was one or more of dichloromethane, n-hexane, or toluene.

[0035] In the embodiments provided by the present invention, the polar monomers with double bonds at the ends include at least one of methyl acrylate, methyl 10-undecenoate, 4-pentenoic acid, 9-decen-1-ol, and 10-undecenol.

[0036] Preferably, in the above applications, the compound containing the terminal alkenyl group is an olefin, more preferably ethylene, and the alkyl aluminum reagent includes one or more of MAO, MMAO, AlMe3, AlEtCl2, AlEt2Cl, and AlEt3.

[0037] This invention provides a highly thermally stable, photoresponsive α-diimine nickel complex. The core photoresponsive switch of this type of nickel complex is a rigid diphenylethylene derivative. Under 365 nm and 405 nm UV irradiation, it can achieve reversible photoisomerization of the E / Z configuration: the E configuration has a relatively open coordination environment; while the Z configuration after irradiation has a more compact spatial structure, forming a dual regulatory mechanism: steric hindrance and potential metal-aryl π-interactions. Specifically, irradiation causes the Z configuration catalyst to form a unique bilayer steric hindrance structure. The first steric hindrance is composed of a flexible isopropyl group at the axial position of the N-aryl group. This group has relatively small steric hindrance, providing sufficient space for the coordination and insertion of ethylene, which helps to improve catalytic activity. The second steric hindrance is composed of a rigid biphenyl group, whose large steric hindrance can effectively suppress side reactions such as chain transfer, thereby significantly increasing the molecular weight of the resulting polymer. Simultaneously, the configurational change induces a potential metal-aryl π-interaction between the metal center and the phenyl group. This interaction can stabilize key intermediates in the polymerization process, further enhancing catalytic performance. Due to this dual regulatory mechanism, the complex exhibits excellent thermal stability at 150°C. o Even at high temperatures, it still maintains a high value of 0.8 × 10⁻⁶. 6 g·mol -1 ·h -1The catalytic activity effectively inhibits chain transfer and chain walking reactions during high-temperature polymerization. Furthermore, this type of complex exhibits good polar monomer tolerance in the copolymerization of ethylene and polar monomers, enabling simultaneous increases in polymer molecular weight and polar monomer insertion rate, successfully preparing polar functionalized polyolefin elastomers. In summary, the nickel complexes developed in this invention synergistically enhance thermal stability through configurational tautomerism, possessing both photoresponsive properties and high catalytic activity, and hold significant research value and broad application prospects in the precise synthesis of functionalized polyolefin materials.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] 1. The α-diimine nickel complex provided by this invention can achieve reversible E / Z configuration transformation under 365 nm and 405 nm ultraviolet light irradiation. Utilizing this photoisomerization property, the coordination environment of the catalytic active center can be dynamically controlled during polymerization, thereby achieving effective regulation of the polymerization reaction rate and precise control of the microstructure of the resulting polymer.

[0040] 2. The E-configuration has a relatively open coordination environment, which is conducive to rapid polymerization. Under 365 nm ultraviolet light irradiation, it can transform into the Z-configuration, which has a double-layer steric hindrance effect and potential metal-aryl π interaction. This Z-configuration can form a rigid and compact protective environment around the active metal center, effectively suppressing chain transfer reactions such as β-H elimination at high temperatures through steric hindrance, and improving the structural stability of the catalyst by stabilizing key intermediates. Through photoisomerization, different polymerization behaviors can be achieved in the same catalytic system. Due to the configurational transformation, the catalyst of this invention still maintains high-efficiency polymerization at 150 °C, with a catalytic activity of 0.8 × 10⁻⁶. 6 g·mol -1 ·h -1 .

[0041] 3. The complexes of this invention exhibit excellent tolerance and catalytic performance in the copolymerization of ethylene and polar monomers. The steric hindrance effect of the Z-configuration effectively avoids the poisoning effect of polar functional groups on the metal center, significantly improves the insertion rate of polar monomers, and yields polar functionalized polyolefin materials with higher molecular weight and lower branching degree. Experimental results show that the prepared polar functionalized polyolefin elastomers have excellent mechanical properties, with an elastic recovery rate of up to 93%. Attached Figure Description

[0042] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0043] Figure 1 This is a single crystal structure diagram of E-(I)-9 provided in Embodiment 18 of the present invention.

[0044] Figure 2 This is a single crystal structure diagram of E-(I)-10 provided in Embodiment 20 of the present invention.

[0045] Figure 3 The UV-Vis absorption spectra of a) E-(I)-9, b) E-(I)-10 and c) E-(I)-11 provided for embodiments 18, 20 and 22 of the present invention.

[0046] Figure 4 The elastic recovery diagram of polyethylene prepared by E-(I)-10 provided in Application Example 27 of the present invention is shown.

[0047] Figure 5 The elastic recovery diagram of polyethylene prepared by E-(I)-10 provided in Application Example 28 of the present invention is shown. Detailed Implementation

[0048] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. It should be understood that the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0049] Unless otherwise specified, the homopolymerization and copolymerization processes of olefins are well known to those skilled in the art and will not be described in detail here.

[0050] The data provided in this invention include the synthesis of ligands, the synthesis of metal complexes, polymerization operations, polymerization conditions, and polymerization products. All operations, including reactions, preparation, and storage, were performed under an inert atmosphere using standard Shrek procedures. Molecular weight and molecular weight distribution were determined by gel permeation chromatography (GPC). Specifically, trichlorobenzene was used as the solvent, and an Agilent PLgel Olexis column was used, with measurements performed on an Agilent PL-200 instrument. Polystyrene was used as a standard, and polyethylene was corrected using Mark-Houwink parameters through a universal calibration: K = 1.75 × 10⁻⁶. -2 cm3 ·g -1 R = 0.67 (polystyrene), K = 5.90 × 10 -2 cm 3 ·g -1 R = 0.69 (polyethylene).

[0051] The preparation methods of α-diimine compounds in the following examples are as follows:

[0052] Unless otherwise specified, the compounds E-3 / Z-3 used in the following examples were prepared as follows: E-1 / Z-1 (2 mmol), commercially available compound 5 (4 mmol), tetrakis(triphenylphosphine)palladium (0.2 mmol), and anhydrous sodium carbonate (10 mmol) were added sequentially to a 200 mL Shrek flask, purging with argon three times. Then, toluene (40 mL), ethanol (4 mL), and water (8 mL) were added. The reaction system was refluxed, and TLC monitoring was performed until the reactants were completely eliminated. After the reaction, the system was cooled to room temperature, and the reaction system was extracted with dichloromethane and deionized water. The organic phase was collected, dried over anhydrous sodium sulfate, concentrated, and then separated by column chromatography to obtain the target compound E-2 / Z-2; wherein the R of compound 5... 1 The substituents were one of hydrogen, phenyl, phenoxy, and phenylthio. Subsequently, E-2 / Z-2 (1 mmol), commercially available compound 6 (2 mmol), tetrakis(triphenylphosphine)palladium (0.2 mmol), and anhydrous sodium carbonate (10 mmol) were added sequentially to a 200 mL Shrek flask, purging the mixture three times with argon. Then, toluene (40 mL), ethanol (8 mL), and water (16 mL) were added. The reaction system was refluxed, and TLC monitoring was performed until the starting material was completely eliminated. After the reaction was complete, the system was cooled to room temperature, and the reaction system was extracted with dichloromethane and deionized water. The organic phase was collected, dried over anhydrous sodium sulfate, concentrated, and then separated by column chromatography to obtain the target compound E-3 / Z-3; wherein the R of compound 6... 2 The substituent is one of hydrogen, methyl, isopropyl, tert-butyl, or phenyl.

[0053] The reaction route is shown below:

[0054]

[0055]

[0056] To more clearly illustrate the embodiments of the present invention, the synthesis methods of the α-diimine ligands and their nickel complexes, as well as their application in ethylene (co)polymerization, will be described in detail below. This section focuses on representative examples, systematically explaining the preparation methods and structural characterization of the (E) configuration ligand (E-4) and its corresponding nickel complex (E-(I)). The synthesis of the (Z) configuration ligand (Z-4) and its corresponding complex (Z-(I)) can be completely referenced to the preparation method of the (E) configuration compound, and the reaction conditions, material ratios, and experimental operations are consistent, so they will not be repeated here.

[0057] Example 1

[0058]

[0059] This embodiment provides a method for synthesizing the α-diimine ligand E-4-1: E-3 (R 1 =R 2 =H) compound (2.5 mmol), compound 7 (1.0 mmol), and ZnCl2 (2.5 mmol) were sequentially added to a 25 mL dry Shrek flask, purged three times with argon gas, and then glacial acetic acid (10 mL) was added. The reaction system was refluxed and monitored by TLC until the starting material was completely eliminated. After the reaction was complete, the reaction mixture was filtered, and the solid was washed with glacial acetic acid and diethyl ether. The solid was dissolved in dichloromethane in a 100 mL round-bottom flask, and a saturated potassium oxalate aqueous solution was added. The mixture was reacted at room temperature for 2 h. The reaction system was extracted with dichloromethane and deionized water, and the organic phase was collected, dried over anhydrous sodium sulfate, concentrated, and purified by recrystallization from dichloromethane / methanol to obtain an orange solid, which was the target compound E-4-1, in 35% yield. Characterization data of this compound: 1 H NMR (600 MHz, CDCl3): δ 8.28 –8.23 (m, 4H), 7.85 (dd, J = 12.3, 2.2 Hz, 4H), 7.78 – 7.72 (m, 2H), 7.69 –7.64 (m, 4H), 7.60 – 7.53 (m, 9H), 7.53 – 7.49 (m, 4H), 7.47 – 7.42 (m, 4H), 7.39 – 7.35 (m, 2H), 7.21 – 7.16 (m, 3H), 3.18 – 3.09 (m, 8H), 3.08 – 3.01(m, 8H) ppm. 13 C{ 1H} NMR (151 MHz, CDCl3): δ 161.3, 150.0, 147.28, 147.25,147.2, 142.6, 142.29, 142.25, 142.2, 138.6, 138.35, 138.31, 137.90, 137.87,137.85, 137.4, 137.1, 131.5, 129.62, 129.60, 129.2, 129.12, 129.08, 128.7,128.2, 127.9, 127.4, 125.86, 125.83, 125.6, 124.3, 124.21, 124.16, 123.5,122.9, 33.7, 33.64, 33.58, 31.2, 31.14, 31.08 ppm.

[0060] Example 2

[0061] The specific synthesis method of nickel complex E-(I)-1:

[0062]

[0063] In an argon-atmospheric glove box, compound E-4-1 (1.00 mmol) prepared in Example 1, (DME)NiBr2 (1.00 mmol), and 20 mL of anhydrous dichloromethane were added sequentially to a 50 mL round-bottom flask, and the reaction was carried out at room temperature for 12 h. After the reaction was completed, the system was concentrated, washed with dry n-hexane solution, and filtered. The solid was recrystallized from n-hexane and dichloromethane to obtain the solid nickel complex E-(I)-1, with a yield of 70%.

[0064] Example 3

[0065]

[0066] This embodiment provides a method for synthesizing the α-diimine ligand E-4-2: the preparation method is the same as in Example 1, except that the substituent in formula E-3 is replaced with R. 1 =Ph; R 2 =H, yielding an orange solid as the target compound E-4-2, in 30% yield. Characterization data for this compound: 1H NMR (600 MHz, CDCl3): δ 8.36 – 8.32 (m, 4H), 8.29 – 8.22 (m, 4H), 7.87 – 7.85 (m, 4H), 7.77 – 7.72 (m, 2H), 7.69 – 7.62 (m, 8H), 7.60 – 7.57(m, 4H), 7.57 – 7.54 (m, 4H), 7.53 – 7.49 (m, 4H), 7.47 – 7.42 (m, 4H), 7.40– 7.35 (m, 2H), 7.21 – 7.17 (m, 4H), 3.14 – 3.09 (m, 8H), 3.06 – 3.02 (m, 8H)ppm. 13 C{ 1 H} NMR (151 MHz, CDCl3): δ 161.3, 150.0, 147.3, 147.25, 147.21,142.6, 142.29, 142.25, 142.2, 141.0, 139.5, 138.9, 138.6, 138.13, 138.10,137.90, 137.87, 137.8, 137.1, 131.5, 129.6, 129.2, 129.1, 128.7, 128.4,128.20, 128.19, 127.9, 127.2, 125.9, 125.8, 125.6, 124.3, 124.21, 124.16,123.5, 122.9, 33.7, 33.61, 33.59, 31.2, 31.12, 31.10 ppm.

[0067] Example 4

[0068] Synthesis of nickel complex E-(I)-2:

[0069]

[0070] The preparation method is the same as in Example 2, except that compound E-4-1 is replaced with compound E-4-2 prepared in Example 3 to prepare E-(I)-2 with a yield of 60%.

[0071] Example 5

[0072]

[0073] This embodiment provides a method for synthesizing the α-diimine ligand E-4-3: the preparation method is the same as in Example 1, except that the substituent in formula E-3 is replaced with R. 1 =OPh; R 2 =H, yielding an orange solid, the target compound E-4-3, in 45% yield. Characterization data for this compound: 1 H NMR (600 MHz, CDCl3): δ 8.29 – 8.22 (m, 4H), 7.86 (d, J = 2.2 Hz, 2H), 7.78 – 7.72 (m, 2H), 7.70 – 7.64 (m, 8H), 7.59 (d, J = 2.2 Hz, 2H), 7.57– 7.47 (m, 8H), 7.38 – 7.33 (m, 4H), 7.26 – 7.16 (m, 8H), 7.11 (tt, J = 7.6,1.6 Hz, 2H), 7.04 – 6.98 (m, 4H), 3.14 – 3.09 (m, 8H), 3.07 – 3.01 (m, 8H)ppm. 13 C{ 1 H} NMR (151 MHz, CDCl3): δ 161.3, 158.0, 156.9, 150.0, 147.28,147.25, 147.21, 142.6, 142.29, 142.25, 142.22, 138.6, 138.11, 138.07, 137.90,137.87, 137.85, 137.1, 135.1, 131.5, 129.7, 129.60, 129.59, 129.16, 129.12,128.7, 128.6, 128.2, 125.68, 125.65, 125.62, 124.5, 124.3, 124.23, 124.16,123.5, 122.9, 120.1, 118.9, 33.69, 33.64, 33.58, 31.2, 31.14, 31.08 ppm.

[0074] Example 6

[0075] Synthesis of nickel complex E-(I)-3:

[0076]

[0077] The preparation method is the same as in Example 2, except that compound E-4-1 is replaced with compound E-4-3 prepared in Example 5 to prepare E-(I)-3 with a yield of 75%.

[0078] Example 7

[0079]

[0080] This embodiment provides a method for synthesizing the α-diimine ligand E-4-4: the preparation method is the same as in Example 1, except that the substituent in formula E-3 is replaced with R. 1 =SPh; R 2 =H, yielding an orange solid, the target compound E-4-4, in 43% yield. Characterization data for this compound: 1 H NMR (600 MHz, CDCl3): δ 8.28 – 8.22 (m, 4H), 7.85 (dd, J = 14.0,2.2 Hz, 4H), 7.77 – 7.73 (m, 2H), 7.71 – 7.65 (m, 8H), 7.56 – 7.53 (m, 4H),7.53 – 7.49 (m, 4H), 7.45 – 7.41 (m, 4H), 7.39 – 7.34 (m, 4H), 7.32 – 7.27(m, 4H), 7.22 – 7.16 (m, 6H), 3.14 – 3.10 (m, 8H), 3.06 – 3.02 (m, 8H) ppm. 13 C{ 1 H} NMR (151 MHz, CDCl3): δ 161.3, 150.0, 147.28, 147.25, 147.21, 142.6,142.29, 142.25, 142.22, 140.7, 138.6, 138.39, 138.36, 137.90, 137.87, 137.85,137.5, 137.1, 136.6, 131.5, 130.7, 130.6, 129.6, 129.2, 129.13, 129.12,128.7, 128.6, 128.2, 127.7, 125.68, 125.65, 125.62, 124.3, 124.20, 124.16,123.5, 122.9, 33.69, 33.64, 33.58, 31.19, 31.14, 31.08 ppm.

[0081] Example 8

[0082] Synthesis of nickel complex E-(I)-4:

[0083]

[0084] The preparation method is the same as in Example 2, except that compound E-4-1 is replaced with compound E-4-4 prepared in Example 7 to prepare E-(I)-4, with a yield of 72%.

[0085] Example 9

[0086]

[0087] This embodiment provides a method for synthesizing the α-diimine ligand E-4-5: the preparation method is the same as in Example 1, except that the substituent in formula E-3 is replaced with R. 1 =H; R 2 =CH3, yielding an orange solid as the target compound E-4-5, in 60% yield. Characterization data for this compound: 1 H NMR (600 MHz, CDCl3): δ 8.29 – 8.21 (m, 4H), 7.84 (d, J = 2.2 Hz, 2H), 7.77 – 7.73 (m, 2H), 7.66 (d, J = 2.3 Hz, 2H), 7.59 – 7.57 (m, 5H), 7.56– 7.49 (m, 8H), 7.44 (t, J = 7.6 Hz, 4H), 7.40 – 7.35 (m, 2H), 7.20 – 7.17(m, 3H), 3.14 – 3.10 (m, 8H), 3.06 – 3.03 (m, 8H), 2.33 (s, 12H) ppm. 13 C{ 1 H}NMR (151 MHz, CDCl3): δ 160.5, 147.4, 147.31, 147.27, 147.2, 142.3, 142.2,141.1, 138.3, 137.90, 137.87, 137.85, 137.4, 137.2, 136.2, 131.5, 131.0,129.7, 129.6, 129.2, 129.1, 129.0, 128.2, 127.9, 127.6, 127.4, 125.8, 125.6,124.7, 124.2, 122.6, 33.7, 33.64, 33.58, 31.2, 31.14, 31.08, 18.7 ppm.

[0088] Example 10

[0089] Synthesis of nickel complex E-(I)-5:

[0090]

[0091] The preparation method is the same as in Example 2, except that compound E-4-1 is replaced with compound E-4-5 prepared in Example 9 to prepare E-(I)-5 with a yield of 78%.

[0092] Example 11

[0093]

[0094] This embodiment provides a method for synthesizing the α-diimine ligand E-4-6: the preparation method is the same as in Example 1, except that the substituent in formula E-3 is replaced with R. 1 =Ph; R 2 =CH3, yielding an orange solid as the target compound E-4-6, in 55% yield. Characterization data for this compound: 1 H NMR (600 MHz, CDCl3): δ 8.37 – 8.32 (m, 4H), 8.29 – 8.21 (m,4H), 7.86 (d, J = 2.1 Hz, 2H), 7.78 – 7.73 (m, 2H), 7.68 – 7.62 (m, 6H), 7.60– 7.48 (m, 12H), 7.46 – 7.43 (m, 4H), 7.39 – 7.35 (m, 2H), 7.20 – 7.16 (m,4H), 3.13 – 3.10 (m, 8H), 3.04 (dd, J = 6.6, 4.9 Hz, 8H), 2.33 (s, 12H) ppm. 13 C{ 1H} NMR (151 MHz, CDCl3): δ 160.5, 147.4, 147.31, 147.27, 147.2, 142.3,142.2, 141.1, 141.0, 139.5, 138.9, 138.1, 137.90, 137.87, 137.85, 137.2,136.2, 131.5, 131.0, 129.7, 129.6, 129.2, 129.1, 129.0, 128.4, 128.20,128.19, 127.9, 127.6, 127.2, 125.8, 125.6, 124.7, 124.2, 122.6, 33.7, 33.64,33.58, 31.2, 31.1, 31.0, 18.7 ppm.

[0095] Example 12

[0096] Synthesis of nickel complex E-(I)-6:

[0097]

[0098] The preparation method is the same as in Example 2, except that compound E-4-1 is replaced with compound E-4-6 prepared in Example 11 to prepare E-(I)-6 with a yield of 78%.

[0099] Example 13

[0100]

[0101] This embodiment provides a method for synthesizing the α-diimine ligand E-4-7: the preparation method is the same as in Example 1, except that the substituent in formula E-3 is replaced with R. 1 =OPh; R 2 =CH3, yielding an orange solid as the target compound E-4-7, in 87% yield. Characterization data for this compound: 1 H NMR (600 MHz, CDCl3): δ 7.98 – 7.96 (m, 4H), 7.87 (s, 2H), 7.65 – 7.60 (m, 7H), 7.50 – 7.36 (m, 20H), 7.17 – 7.10 (m, 12H), 6.97 (d, J = 7.1Hz, 2H), 3.43 – 3.42 (m, 4H), 3.36 – 3.32 (m, 6H), 3.27 – 3.20 (m, 10H), 2.29(s, 12H) ppm. 13 C{1 H} NMR (151 MHz, CDCl3): δ 160.5, 158.0, 156.9, 147.4,147.31, 147.27, 147.23, 142.3, 142.2, 141.1, 138.0, 137.90, 137.87, 137.85,137.2, 136.2, 135.1, 131.5, 131.0, 129.8, 129.7, 129.6, 129.2, 129.0, 128.6,128.2, 127.6, 125.62, 125.57, 124.7, 124.5, 124.2, 122.6, 120.1, 118.9, 33.7,33.64, 33.58, 31.2, 31.1, 31.0, 18.7 ppm.

[0102] Example 14

[0103] Synthesis of nickel complex E-(I)-7:

[0104]

[0105] The preparation method is the same as in Example 2, except that compound E-4-1 is replaced with compound E-4-7 prepared in Example 13 to prepare E-(I)-7 with a yield of 85%.

[0106] Example 15

[0107]

[0108] This embodiment provides a method for synthesizing the α-diimine ligand E-4-8: the preparation method is the same as in Example 1, except that the substituent in formula E-3 is replaced with R. 1 =SPh; R 2 =CH3, yielding an orange solid, the target compound E-4-7, in 80% yield. Characterization data for this compound: 1H NMR (600 MHz, CDCl3): δ 8.31 – 8.21 (m, 4H), 7.84 (d, J = 2.2Hz, 2H), 7.77 – 7.73 (m, 2H), 7.72 – 7.65 (m, 6H), 7.56 – 7.48 (m, 8H), 7.45– 7.41 (m, 4H), 7.39 – 7.34 (m, 4H), 7.30 – 7.27 (m, 4H), 7.23 – 7.16 (m,6H), 3.14 – 3.09 (m, 8H), 3.07 – 3.02 (m, 8H), 2.33 (s, 12H) ppm. 13 C{ 1 H} NMR(151 MHz, CDCl3): δ 160.5, 147.4, 147.31, 147.27, 147.2, 142.3, 142.2, 141.1,140.7, 138.3, 137.90, 137.87, 137.85, 137.4, 137.2, 136.6, 136.2, 131.5,131.0, 130.7, 130.6, 129.7, 129.6, 129.2, 129.1, 129.0, 128.6, 128.2, 127.7,127.6, 125.62, 125.57, 124.7, 124.2, 122.6, 33.7, 33.64, 33.58, 31.2, 31.14,31.08, 18.7 ppm.

[0109] Example 16

[0110] Synthesis of nickel complex E-(I)-8:

[0111]

[0112] The preparation method is the same as in Example 2, except that compound E-4-1 is replaced with compound E-4-8 prepared in Example 15 to prepare E-(I)-8 with a yield of 79%.

[0113] Example 17

[0114]

[0115] This embodiment provides a method for synthesizing the α-diimine ligand E-4-9: the preparation method is the same as in Example 1, except that the substituent in formula E-3 is replaced with R. 1 =H; R2 = i Pr yielded an orange solid, which was the target compound E-4-9, in 86% yield. Characterization data for this compound: 1 H NMR (600 MHz, CDCl3): δ 7.98 (s, 2H), 7.91 – 7.81 (m, 4H), 7.65 (d, J = 7.7 Hz, 4H), 7.61 – 7.55 (m, 6H), 7.48 – 7.40 (m, 12H), 7.38 – 7.35(m, 2H), 6.86 (d, J = 7.3 Hz, 2H), 3.40 – 3.33 (m, 8H), 3.23 – 3.20 (m, 8H), 3.13 (hetp, J = 6.9 Hz, 4H), 1.34 (d, J = 6.8 Hz, 12H), 1.08 (d, J = 7.0 Hz,12H) ppm. 13 C{ 1 H} NMR (151 MHz, CDCl3): δ 161.2, 146.9, 146.4, 146.0, 144.0,143.9, 142.0, 140.9, 140.5, 139.9, 137.7, 136.0, 135.9, 135.6, 131.2, 129.6,129.0, 128.8, 128.0, 127.3, 127.1, 126.3, 125.25, 125.21, 123.55, 123.47,123.1, 122.5, 32.5, 32.2, 31.0, 30.9, 28.9, 23.5, 23.3 ppm.

[0116] Example 18

[0117] Synthesis of nickel complex E-(I)-9:

[0118]

[0119] The preparation method is the same as in Example 2, except that compound E-4-1 is replaced with compound E-4-9 prepared in Example 17 to prepare E-(I)-9 with a yield of 88%.

[0120] Example 19

[0121]

[0122] This embodiment provides a method for synthesizing the α-diimine ligand E-4-10: the preparation method is the same as in Example 1, except that the substituent in formula E-3 is replaced with R. 1 =Ph; R 2 = i Pr yielded an orange solid, which was the target compound E-4-10, in 46% yield. Characterization data for this compound: 1 H NMR (600 MHz, CDCl3): δ 7.99 (s, 2H), 7.92 – 7.90 (m, 4H), 7.75– 7.70 (m, 8H), 7.67 (d, J = 7.5 Hz, 4H), 7.61 – 7.58 (m, 6H), 7.51 – 7.40(m, 12H), 7.38 – 7.36 (m, 2H), 6.86 (d, J = 7.3 Hz, 2H), 3.40 – 3.35 (m, 8H), 3.25 – 3.21 (m, 8H), 3.13 (hept, J = 6.8 Hz, 4H), 1.34 (d, J = 7.0 Hz, 12H),1.08 (d, J = 7.0 Hz, 12H) ppm. 13 C{ 1 H} NMR (151 MHz, CDCl3): δ 161.2, 146.9.146.5, 146.0, 144.0, 143.9, 140.9, 140.8, 140.5, 140.0, 139.3, 137.7, 136.0,135.9, 135.5, 131.2, 129.6, 129.0, 128.9, 128.0, 127.7, 127.6, 127.3, 127.1,126.3, 126.2, 125.3, 125.2, 123.5, 123.3, 123.1, 122.5, 32.6, 32.2, 31.0,30.9, 28.9, 23.5, 23.3 ppm.

[0123] Example 20

[0124] Synthesis of nickel complex E-(I)-10:

[0125]

[0126] The preparation method is the same as in Example 2, except that compound E-4-1 is replaced with compound E-4-10 prepared in Example 19, which can be used to prepare E-(I)-10 with a yield of 61%.

[0127] Example 21

[0128]

[0129] This embodiment provides a method for synthesizing the α-diimine ligand E-4-11: the preparation method is the same as in Example 1, except that the substituent in formula E-3 is replaced with R. 1 =OPh; R 2 = i Pr yielded an orange solid, which was the target compound E-4-11, in 81% yield. Characterization data for this compound: 1 H NMR (600 MHz, CDCl3): δ 8.01 (s, 2H), 7.95 (d, J = 8.2 Hz,2H), 7.88 (s, 2H), 7.66 – 7.60 (m, 10H), 7.50 – 7.44 (m, 8H), 7.41 (t, J =7.9 Hz, 4H), 7.18 – 7.12 (m, 10H), 6.89 (d, J = 7.3 Hz, 2H), 3.44 – 3.37 (m,8H), 3.27 – 3.24 (m, 8H), 3.20 – 3.15 (m, 4H), 1.37 (d, J = 6.8 Hz, 12H),1.11 (d, J = 7.0 (Hz, 12H) ppm. 13 C{ 1 H} NMR (151 MHz, CDCl3): δ 158.7, 158.1,152.6, 147.1, 147.0, 146.9, 141.7, 141.6, 139.8, 138.90, 138.89, 136.8,135.3, 135.0, 133.4, 132.5, 129.9, 129.7, 129.0, 128.6, 128.3, 128.0, 126.79,126.77, 126.4, 125.7, 124.9, 124.5, 121.1, 120.1, 119.7, 35.1, 31.4, 30.3, 24.0 ppm.

[0130] Example 22

[0131] Synthesis of nickel complex E-(I)-11:

[0132]

[0133] The preparation method is the same as in Example 2, except that compound E-4-1 is replaced with compound E-4-11 prepared in Example 21, which can be used to prepare E-(I)-11 with a yield of 73%.

[0134] Example 23

[0135]

[0136] This embodiment provides a method for synthesizing the α-diimine ligand E-4-12: the preparation method is the same as in Example 1, except that the substituent in formula E-3 is replaced with R. 1 =SPh; R 2 = i Pr yielded an orange solid, which was the target compound E-4-12, in 83% yield. Characterization data for this compound are as follows: 1 H NMR (600 MHz, CDCl3): δ 8.45 (dd, J = 7.5, 1.2 Hz, 2H), 8.27 (dt, J = 7.1, 0.9 Hz, 2H), 7.84 (d, J = 2.2 Hz, 2H), 7.78 – 7.73 (m, 2H), 7.71 – 7.67 (m, 6H), 7.57 – 7.49 (m, 8H), 7.45 – 7.41 (m, 4H), 7.39 – 7.35(m, 4H), 7.31 – 7.26 (m, 4H), 7.22 – 7.15 (m, 6H), 3.45 (hept, J = 6.1, 0.9Hz, 4H), 3.15 – 3.10 (m, 8H), 3.07 – 3.02 (m, 8H), 1.34 (d, J = 6.2 Hz, 24H)ppm. 13 C{ 1 H} NMR (151 MHz, CDCl3): δ 152.6, 147.1, 147.0, 146.9, 141.7, 141.6,139.8, 139.3, 138.9, 137.4, 136.9, 136.8, 135.3, 135.0, 133.4, 132.0, 131.0,129.7, 129.1, 128.7, 128.6, 128.3, 128.1, 128.0, 126.79, 126.77, 126.4,125.7, 124.9, 121.1, 35.1, 31.4, 30.3, 24.0 ppm.

[0137] Example 24

[0138] Synthesis of nickel complex E-(I)-12:

[0139]

[0140] The preparation method is the same as in Example 2, except that compound E-4-1 is replaced with compound E-4-12 prepared in Example 23 to prepare E-(I)-12 with a yield of 68%.

[0141] Example 25

[0142]

[0143] This embodiment provides a method for synthesizing the α-diimine ligand E-4-13: the preparation method is the same as in Example 1, except that the substituent in formula E-3 is replaced with R. 1 =H; R 2 = t Bu yielded an orange solid, which was the target compound E-4-13, in 73% yield. Characterization data for this compound are as follows: 1 H NMR (600 MHz, CDCl3): δ 8.57 (dd, J = 7.3, 1.0 Hz, 2H), 8.30 –8.24 (m, 2H), 7.93 (s, 3H), 7.84 (d, J = 2.2 Hz, 2H), 7.78 – 7.72 (m, 2H),7.68 (d, J = 2.1 Hz, 2H), 7.61 – 7.50 (m, 9H), 7.47 – 7.41 (m, 4H), 7.40 –7.34 (m, 2H), 7.25 – 7.16 (m, 4H), 3.13 – 3.10 (m, 8H), 3.06 – 3.03 (m, 8H), 1.39 (s, 36H) ppm. 13 C{ 1H} NMR (151 MHz, CDCl3): δ 155.6, 147.31, 147.27,147.2, 142.3, 142.2, 141.1, 140.3, 139.5, 138.3, 138.1, 137.90, 137.87,137.85, 137.4, 131.5, 130.5, 129.6, 129.2, 129.1, 128.3, 128.2, 127.9, 127.4,125.8, 125.6, 124.7, 124.6, 124.2, 122.5, 35.5, 33.7, 33.6, 33.5, 31.2,31.14, 31.08, 30.3 ppm.

[0144] Example 26

[0145] Synthesis of nickel complex E-(I)-13:

[0146]

[0147] The preparation method is the same as in Example 2, except that compound E-4-1 is replaced with compound E-4-13 prepared in Example 25, so that E-(I)-13 can be prepared with a yield of 65%.

[0148] Example 27

[0149]

[0150] This embodiment provides a method for synthesizing the α-diimine ligand E-4-14: the preparation method is the same as in Example 1, except that the substituent in formula E-3 is replaced with R. 1 =Ph; R 2 = t Bu yielded an orange solid, which was the target compound E-4-14, in 66% yield. Characterization data for this compound are as follows: 1H NMR (600 MHz, CDCl3): δ 8.57 (dd, J = 7.3, 1.0 Hz, 2H), 8.36 –8.32 (m, 4H), 8.29 – 8.25 (m, 2H), 7.93 (s, 4H), 7.86 (d, J = 2.1 Hz, 2H), 7.78 – 7.73 (m, 2H), 7.68 (d, J = 2.1 Hz, 2H), 7.66 – 7.63 (m, 4H), 7.60 –7.57 (m, 4H), 7.55 (dd, J = 8.4, 2.2 Hz, 2H), 7.51 (dd, J = 8.4, 2.2 Hz, 2H),7.47 – 7.42 (m, 4H), 7.39 – 7.35 (m, 2H), 7.24 – 7.17 (m, 4H), 3.13 – 3.10 (m, 8H), 3.06 – 3.03 (m, 8H), 1.39 (s, 36H) ppm. 13 C{ 1 H} NMR (151 MHz, CDCl3): δ 152.9, 147.1, 147.0, 145.4, 142.3, 142.0, 141.7, 141.6, 140.7, 140.6,139.2, 138.9, 136.82, 136.77, 135.3, 133.0, 130.2, 129.7, 128.7, 128.6,128.5, 128.4, 128.3, 128.2, 127.8, 126.9, 126.8, 126.4, 125.7, 124.0, 121.1,35.1, 35.0, 31.4, 30.2 ppm.

[0151] Example 28

[0152] Synthesis of nickel complex E-(I)-14:

[0153]

[0154] The preparation method is the same as in Example 2, except that compound E-4-1 is replaced with compound E-4-14 prepared in Example 27 to prepare E-(I)-14 with a yield of 80%.

[0155] Example 29

[0156]

[0157] This embodiment provides a method for synthesizing the α-diimine ligand E-4-15: the preparation method is the same as in Example 1, except that the substituent in formula E-3 is replaced with R. 1 =OPh; R 2 = t Bu yielded an orange solid, which was the target compound E-4-15, in 78% yield. Characterization data for this compound are as follows: 1 H NMR (600 MHz, CDCl3): δ 8.57 (dd, J = 7.3, 1.0 Hz, 2H), 8.29 –8.24 (m, 2H), 7.93 (s, 4H), 7.79 – 7.73 (m, 2H), 7.71 – 7.65 (m, 6H), 7.59(d, J = 2.2 Hz, 2H), 7.56 – 7.51 (m, 4H), 7.39 – 7.32 (m, 4H), 7.25 – 7.17(m, 8H), 7.11 (tt, J = 7.6, 1.6 Hz, 2H), 7.05 – 6.99 (m, 4H), 3.13 – 3.10 (m, 8H), 3.06 – 3.03 (m, 8H), 1.39 (s, 36H) ppm. 13 C{ 1 H} NMR (151 MHz, CDCl3): δ158.7, 158.1, 152.9, 147.1, 147.0, 145.4, 142.3, 141.7, 141.6, 140.6, 138.9,136.82, 136.77, 135.3, 133.0, 132.5, 129.9, 129.7, 129.0, 128.6, 128.4,128.3, 126.79, 126.77, 126.4, 125.7, 124.5, 124.0, 121.1, 120.1, 119.7,35.14, 35.08, 31.4, 30.2 ppm.

[0158] Example 30

[0159] Synthesis of nickel complex E-(I)-15:

[0160]

[0161] The preparation method is the same as in Example 2, except that compound E-4-1 is replaced with compound E-4-15 prepared in Example 29, which can be used to prepare E-(I)-15 with a yield of 81%.

[0162] Example 31

[0163]

[0164] This embodiment provides a method for synthesizing the α-diimine ligand E-4-16: the preparation method is the same as in Example 1, except that the substituent in formula E-3 is replaced with R. 1 =SPh; R 2 = t Bu yielded an orange solid, the target compound E-4-16, in 70% yield. Characterization data for this compound are as follows: 1 H NMR (600 MHz, CDCl3): δ 8.57 (dd, J = 7.3, 1.0 Hz, 2H), 8.34 –8.17 (m, 2H), 7.93 (s, 4H), 7.84 (d, J = 2.2 Hz, 2H), 7.78 – 7.73 (m, 2H),7.72 – 7.67 (m, 6H), 7.55 – 7.51 (m, 4H), 7.45 – 7.41 (m, 4H), 7.39 – 7.34(m, 4H), 7.31 – 7.27 (m, 4H), 7.24 – 7.16 (m, 6H), 3.14 – 3.09 (m, 8H), 3.07– 3.02 (m, 8H), 1.39 (s, 36H) ppm. 13 C{ 1 H} NMR (151 MHz, CDCl3): δ 152.9,147.1, 147.0, 145.4, 142.3, 141.7, 141.6, 140.5, 139.3, 137.4, 136.9, 136.8,136.7, 135.2, 133.0, 132.0, 130.9, 129.7, 129.1, 128.7, 128.6, 128.4, 128.3,128.0, 126.8, 126.7, 126.4, 125.6, 124.0, 121.1, 35.1, 35.0, 31.4, 30.2 ppm.

[0165] Example 32

[0166] Synthesis of nickel complex E-(I)-16:

[0167]

[0168] The preparation method is the same as in Example 2, except that compound E-4-1 is replaced with compound E-4-16 prepared in Example 31, which can be used to prepare E-(I)-16 with a yield of 75%.

[0169] Example 33

[0170]

[0171] This embodiment provides a method for synthesizing the α-diimine ligand E-4-17: the preparation method is the same as in Example 1, except that the substituent in formula E-3 is replaced with R. 1 =H; R 2 =Ph, yielding an orange solid, which was the target compound E-4-17, in 30% yield. Characterization data of this compound: 1 H NMR (600 MHz, CDCl3): δ 8.48 (dd, J = 7.5, 1.2 Hz, 2H), 8.29 –8.25 (m, 2H), 7.95 (s, 3H), 7.88 (d, J = 2.2 Hz, 2H), 7.84 (d, J = 2.3 Hz,2H), 7.77 – 7.73 (m, 2H), 7.72 – 7.68 (m, 8H), 7.61 – 7.56 (m, 4H), 7.56 –7.51 (m, 4H), 7.48 – 7.42 (m, 13H), 7.40 – 7.35 (m, 6H), 7.19 (ddt, J = 9.3,8.3, 0.9 Hz, 4H), 3.12 (t, J = 5.6 Hz, 8H), 3.04 (dd, J = 6.7, 4.8 Hz, 8H)ppm. 13 C{ 1 H} NMR (151 MHz, CDCl3): δ 155.3, 147.34, 147.32, 147.2, 147.1,142.2, 142.1, 141.1, 138.3, 138.2, 138.1, 137.94, 137.91, 137.8, 137.4,137.1, 133.5, 131.5, 130.6, 129.6, 129.2, 129.1, 128.6, 128.5, 128.2, 128.1,127.9, 127.7, 127.4, 125.8, 125.5, 124.6, 124.2, 122.5, 33.7, 33.6, 33.4,31.2, 31.1, 31.0 ppm.

[0172] Example 34

[0173] Synthesis of nickel complex E-(I)-17:

[0174]

[0175] The preparation method is the same as in Example 2, except that compound E-4-1 is replaced with compound E-4-17 prepared in Example 33, so that E-(I)-17 can be prepared with a yield of 60%.

[0176] Example 35

[0177]

[0178] This embodiment provides a method for synthesizing the α-diimine ligand E-4-18: the preparation method is the same as in Example 1, except that the substituent in formula E-3 is replaced with R. 1 =R 2 =Ph, yielding an orange solid as the target compound E-4-18, in 35% yield. Characterization data for this compound: 1 H NMR (600 MHz, CDCl3): δ 8.48 (dd, J = 7.5, 1.2 Hz, 2H), 8.36 – 8.31(m, 4H), 8.27 (dd, J = 7.5, 1.3 Hz, 2H), 7.95 (s, 4H), 7.87 (dd, J = 14.0,2.2 Hz, 4H), 7.75 (dd, J = 8.3, 7.3 Hz, 2H), 7.70 (dt, J = 8.4, 1.7 Hz, 8H),7.66 – 7.62 (m, 4H), 7.60 – 7.57 (m, 4H), 7.56 – 7.50 (m, 4H), 7.48 – 7.42(m, 12H), 7.40 – 7.35 (m, 6H), 7.23 – 7.17 (m, 4H), 3.13 – 3.09 (m, 8H), 3.07– 3.02 (m, 8H) ppm. 13 C{ 1H} NMR (151 MHz, CDCl3): δ 154.1, 147.1, 146.4,146.3, 142.0, 141.6, 141.5, 140.7, 139.2, 138.9, 138.7, 138.6, 136.8, 136.1,135.8, 135.2, 133.3, 130.5, 130.2, 129.7, 128.7, 128.6, 128.5, 128.4, 128.3,128.2, 128.1, 128.0, 127.8, 127.2, 127.0, 126.8, 126.4, 125.7, 121.0, 35.1, 31.4 ppm.

[0179] Example 36

[0180] Synthesis of nickel complex E-(I)-18:

[0181]

[0182] The preparation method is the same as in Example 2, except that compound E-4-1 is replaced with compound E-4-18 prepared in Example 35, so that E-(I)-18 can be prepared with a yield of 61%.

[0183] Example 37

[0184]

[0185] This embodiment provides a method for synthesizing the α-diimine ligand E-4-19: the preparation method is the same as in Example 1, except that the substituent in formula E-3 is replaced with R. 1 =OPh; R 2 =Ph, yielding an orange solid, the target compound E-4-19, in 50% yield. Characterization data for this compound: 1H NMR (600 MHz, CDCl3): δ 8.48 (dd, J = 7.5, 1.2 Hz, 2H), 8.27 (dd, J = 7.5, 1.3 Hz, 2H), 7.95 (s, 4H), 7.88 (d, J = 2.2 Hz, 2H), 7.75 (dd,J = 8.3, 7.2 Hz, 2H), 7.72 – 7.66 (m, 12H), 7.59 (d, J = 2.2 Hz, 2H), 7.53(ddd, J = 10.8, 8.4, 2.2 Hz, 4H), 7.47 – 7.42 (m, 8H), 7.39 – 7.32 (m, 8H),7.25 – 7.17 (m, 8H), 7.11 (tt, J = 7.6, 1.6 Hz, 2H), 7.04 – 6.99 (m, 4H), 3.14 – 3.09 (m, 8H), 3.07 – 3.02 (m, 8H) ppm. 13 C{ 1 H} NMR (151 MHz, CDCl3): δ158.7, 158.1, 154.1, 147.1, 146.42, 146.36, 141.6, 141.5, 138.9, 138.7,138.6, 136.8, 136.1, 135.8, 135.2, 133.3, 132.5, 130.5, 129.9, 129.7, 129.0,128.7, 128.6, 128.5, 128.4, 128.3, 127.2, 126.8, 126.7, 126.4, 125.7, 124.5,121.0, 120.2, 119.8, 35.1, 31.4 ppm.

[0186] Example 38

[0187] Synthesis of nickel complex E-(I)-19:

[0188]

[0189] The preparation method is the same as in Example 2, except that compound E-4-1 is replaced with compound E-4-19 prepared in Example 37 to prepare E-(I)-19 with a yield of 70%.

[0190] Example 39

[0191]

[0192] This embodiment provides a method for synthesizing the α-diimine ligand E-4-20: the preparation method is the same as in Example 1, except that the substituent in formula E-3 is replaced with R. 1 =SPh; R 2 =Ph, yielding an orange solid as the target compound E-4-20, with a yield of 48%. Characterization data for this compound: 1 H NMR (600 MHz, CDCl3): δ 8.48 (dd, J = 7.5, 1.2 Hz, 2H), 8.27 (dd, J = 7.5, 1.3 Hz, 2H), 7.95 (s, 4H), 7.88 (d, J = 2.2 Hz, 2H), 7.84 (d, J= 2.2 Hz, 2H), 7.75 (dd, J = 8.3, 7.2 Hz, 2H), 7.72 – 7.68 (m, 12H), 7.57 –7.48 (m, 4H), 7.48 – 7.41 (m, 12H), 7.37 (ddt, J = 8.6, 5.7, 1.3 Hz, 8H),7.31 – 7.27 (m, 4H), 7.23 – 7.16 (m, 6H), 3.12 (t, J = 5.6 Hz, 8H), 3.04 (dd,J = 6.7, 4.8 Hz, 8H) ppm. 13 C{ 1 H} NMR (151 MHz, CDCl3): δ 154.1, 147.1, 146.4,146.3, 141.6, 141.5, 139.3, 138.7, 138.6, 137.4, 136.9, 136.8, 136.1, 135.8,135.2, 133.3, 132.0, 131.0, 130.5, 129.7, 129.1, 128.8, 128.7, 128.6, 128.5,128.4, 128.3, 128.0, 127.2, 126.8, 126.7, 126.4, 125.7, 121.0, 35.1, 31.4 ppm.

[0193] Example 40

[0194] Synthesis of nickel complex E-(I)-20:

[0195]

[0196] The preparation method is the same as in Example 2, except that compound E-4-1 is replaced with compound E-4-20 prepared in Example 39, which can be used to prepare E-(I)-20 with a yield of 66%.

[0197] Application Examples 1-22 provide data on the homopolymerization of ethylene catalyzed by α-diimine nickel complexes.

[0198] According to the appendix Figure 3 The UV-Vis absorption spectra revealed that the α-diimine nickel complexes E-(I)-9 and E-(I)-10 exhibited a stable state after irradiation with 365 nm UV light for 450 s, indicating that there was no longer a conversion from the E configuration to the Z configuration. Therefore, the irradiation time for the prepolymerization catalysts E-(I)-9 and E-(I)-10 was selected as 8 min. The α-diimine nickel complex E-(I)-11 exhibited a stable state after irradiation with 365 nm UV light for 540 s. Therefore, the irradiation time for the prepolymerization catalyst E-(I)-11 was selected as 9 min.

[0199] Application Example 1

[0200] In an argon-atmosphere glove box, anhydrous toluene (48 mL) was added to a 350 mL thick-walled quartz dish. The dish was then connected to the ethylene gas line, and three ethylene gas replacements were performed. AlEt₂Cl (0.5 mL, 1 M intoluene) was then added. The mixture was preheated at 50 °C and stirred. A solution of 1 μmol of α-diimine nickel complex E-(I)-9 in dichloromethane (2 mL) was then injected, and the ethylene pressure was adjusted to 0.2 MPa. The mixture was stirred for 20 min. After the reaction was complete, 100 mL of acidified ethanol solution (5% HCl in EtOH) was added to quench the reaction. The mixture was stirred at room temperature for 12 h, filtered, and the product was washed several times with ethanol and dried to constant weight. Specific experimental results are shown in Table 1.

[0201] Application Example 2

[0202] The experimental procedure was the same as in Application Example 1, except that the α-diimine nickel complex E-(I)-9 was irradiated with 365 nm ultraviolet light for 8 min before being injected into the polymerization system. The results are shown in Table 1.

[0203] Table 1

[0204]

[0205] The experimental procedure was the same as in Application Example 1, except that the reaction temperature was changed to 80 °C. The results are shown in Table 2.

[0206] Application Example 4

[0207] The experimental procedure was the same as in Application Example 1, except that the reaction temperature was changed to 80 °C, and the α-diimine nickel complex E-(I)-9 was injected into the polymerization system after being irradiated with 365 nm ultraviolet light for 8 min. The results are shown in Table 2.

[0208] Table 2

[0209]

[0210] Application Examples 1-4 demonstrate the catalytic performance of catalyst E-(I)-9 at 50 °C and 80 °C under ethylene pressure of 0.2 MPa and reaction conditions of 20 min. Experimental results show that the catalyst maintains a high performance of 7.19 × 10⁻⁶ even at 80 °C. 6 g·mol -1 ·h -1 The catalyst exhibited good thermal stability. However, as the temperature increased from 50 °C to 80 °C, both the catalyst activity and the molecular weight of the resulting polymer decreased. This is mainly attributed to two factors: firstly, the increased temperature reduced the solubility of ethylene in toluene; secondly, the high temperature caused partial decomposition of the catalyst, leading to a decrease in activity. Simultaneously, the higher polymerization temperature also accelerated the chain transfer reaction during polymerization, resulting in a decrease in polymer molecular weight. Comparing experimental data under dark and light conditions, no significant differences were observed. It is speculated that this is because after irradiation with 365 nm ultraviolet light, the phenyl group (R2) undergoes a chain transfer reaction from the E-form to the Z-form, resulting in a decrease in the molecular weight of the polymer. 1 =Ph) is far from the metal center and fails to form an effective metal-aryl π interaction. Therefore, it has a weak influence on the electronic structure and coordination environment of the metal center, resulting in no significant difference in catalytic behavior between the two states.

[0211] Application Example 5

[0212] In an argon-atmosphere glove box, anhydrous toluene (48 mL) was added to a 350 mL thick-walled quartz dish. The dish was then connected to the ethylene gas line, and three ethylene gas replacements were performed. AlEt₂Cl (0.5 mL, 1 M intoluene) was then added. The mixture was preheated and stirred at 25 °C, followed by the injection of a 2 mL solution of 1 μmol of the α-diimine nickel complex E-(I)-10 in dichloromethane. The ethylene pressure was adjusted to 0.2 MPa, and the reaction was stirred for 20 min. After the reaction was complete, 100 mL of acidified ethanol solution (5% HCl in EtOH) was added to quench the reaction. The mixture was stirred at room temperature for 12 h, filtered, and the product was washed several times with ethanol and dried to constant weight. Specific experimental results are shown in Table 3.

[0213] Application Example 6

[0214] The experimental procedure was the same as in Application Example 5, except that the α-diimine nickel complex E-(I)-10 was irradiated with 365 nm ultraviolet light for 8 min before being injected into the polymerization system. The results are shown in Table 3.

[0215] Table 3

[0216]

[0217] Application Example 7

[0218] The experimental procedure was the same as in Application Example 5, except that the reaction temperature was changed to 50 °C. The results are shown in Table 4.

[0219] Application Example 8

[0220] The experimental procedure was the same as in Application Example 5, except that the reaction temperature was changed to 50 °C, and the α-diimine nickel complex E-(I)-10 was injected into the polymerization system after being irradiated with 365 nm ultraviolet light for 8 min. The results are shown in Table 4.

[0221] Table 4

[0222]

[0223] Application Example 9

[0224] The experimental procedure was the same as in Application Example 5, except that the reaction temperature was changed to 80 °C. The results are shown in Table 5.

[0225] Application Example 10

[0226] The experimental procedure was the same as in Application Example 5, except that the reaction temperature was changed to 80 °C, and the α-diimine nickel complex E-(I)-10 was injected into the polymerization system after being irradiated with 365 nm ultraviolet light for 8 min. The results are shown in Table 5.

[0227] Table 5

[0228]

[0229] Application Example 11

[0230] The experimental procedure was the same as in Application Example 5, except that the reaction temperature was changed to 100 °C. The results are shown in Table 6.

[0231] Application Example 12

[0232] The experimental procedure was the same as in Application Example 5, except that the reaction temperature was changed to 100 °C, and the α-diimine nickel complex E-(I)-10 was injected into the polymerization system after being irradiated with 365 nm ultraviolet light for 8 min. The results are shown in Table 6.

[0233] Table 6

[0234]

[0235] Application Example 13

[0236] The experimental procedure was the same as in Application Example 5, except that the reaction temperature was changed to 120 °C. The results are shown in Table 7.

[0237] Application Example 14

[0238] The experimental procedure was the same as in Application Example 5, except that the reaction temperature was changed to 120 °C, and the α-diimine nickel complex E-(I)-10 was injected into the polymerization system after being irradiated with 365 nm ultraviolet light for 8 min. The results are shown in Table 7.

[0239] Table 7

[0240]

[0241] Application Example 15

[0242] The experimental procedure was the same as in Application Example 5, except that the reaction temperature was changed to 150 °C. The results are shown in Table 8.

[0243] Application Example 16

[0244] The experimental procedure was the same as in Application Example 5, except that the reaction temperature was changed to 150 °C, and the α-diimine nickel complex E-(I)-10 was injected into the polymerization system after being irradiated with 365 nm ultraviolet light for 8 min. The results are shown in Table 8.

[0245] Table 8

[0246]

[0247] Application Examples 5-16 demonstrate the catalytic performance of catalyst E-(I)-10 at 25℃–150℃ under conditions of 0.2 MPa ethylene pressure and 20 min reaction time. Experimental results show that the catalyst maintains a high catalytic strength of 0.84 × 10⁻⁶ even at 150℃. 6 g·mol -1 ·h -1The catalytic activity indicates that the catalyst possesses high thermal stability. With increasing temperature, the catalyst activity first increases and then decreases, reaching its highest level at 50 °C. The molecular weight of the resulting polymer decreases. This is because higher polymerization temperatures accelerate chain transfer reactions during polymerization, leading to a decrease in polymer molecular weight. Furthermore, comparing experimental data under dark and light conditions reveals significantly different catalytic behaviors. After light irradiation, the catalyst activity increases, the molecular weight of the resulting polymer increases, and the branching degree decreases. This is because irradiation with 365 nm ultraviolet light transforms the catalyst from the E-form to the Z-form, giving it a double-layer steric hindrance and potential metal-aryl π interactions. This structural transformation creates a more rigid and compact protective environment around the active metal center, inhibiting chain transfer and chain walking processes such as β-H elimination through steric shielding, and stabilizing key intermediates through metal-aryl π interactions. Therefore, light irradiation increases the catalyst activity, increases the molecular weight of the resulting polymer, and decreases the branching degree. Simultaneously, it effectively improves the structural stability of the catalyst at high temperatures, enhancing its thermal stability.

[0248] Application Example 17

[0249] In an argon-atmosphere glove box, anhydrous toluene (48 mL) was added to a 350 mL thick-walled quartz dish. The dish was then connected to the ethylene gas line, and three ethylene gas replacements were performed. AlEt₂Cl (0.5 mL, 1 M intoluene) was then added. The mixture was preheated and stirred at 25 °C, followed by the injection of a 2 mL solution of 1 μmol of the α-diimine nickel complex E-(I)-11 in dichloromethane. The ethylene pressure was adjusted to 0.2 MPa, and the reaction was stirred for 20 min. After the reaction was complete, 100 mL of acidified ethanol solution (5% HCl in EtOH) was added to quench the reaction. The mixture was stirred at room temperature for 12 h, filtered, and the product was washed several times with ethanol and dried to constant weight. Specific experimental results are shown in Table 9.

[0250] Application Example 18

[0251] The experimental procedure was the same as in Application Example 17, except that the α-diimine nickel complex E-(I)-11 was irradiated with 365 nm ultraviolet light for 9 min before being injected into the polymerization system. The results are shown in Table 9.

[0252] Table 9

[0253]

[0254] Application Example 19

[0255] The experimental procedure was the same as in Application Example 17, except that the reaction temperature was changed to 50 °C. The results are shown in Table 10.

[0256] Application Example 20

[0257] The experimental procedure was the same as in Application Example 17, except that the reaction temperature was changed to 50 °C, and the α-diimine nickel complex E-(I)-11 was injected into the polymerization system after being irradiated with 365 nm ultraviolet light for 9 min. The results are shown in Table 10.

[0258] Table 10

[0259]

[0260] Application Example 21

[0261] The experimental procedure was the same as in Application Example 17, except that the reaction temperature was changed to 80 °C. The results are shown in Table 11.

[0262] Application Example 22

[0263] The experimental procedure was the same as in Application Example 17, except that the reaction temperature was changed to 80 °C, and the α-diimine nickel complex E-(I)-11 was injected into the polymerization system after being irradiated with 365 nm ultraviolet light for 9 min. The results are shown in Table 11.

[0264] Table 11

[0265]

[0266] Application Examples 17-22 demonstrate the catalytic performance of catalyst E-(I)-11 at 25 °C to 80 °C under ethylene pressure of 0.2 MPa and reaction time of 20 min. Experimental results show that the catalyst maintains a high catalytic activity of 6.36 × 10⁻⁶ even at 80 °C. 6 g·mol -1 ·h -1 The catalyst exhibits good thermal stability and catalytic activity. As the temperature increases from 20 °C to 80 °C, the catalyst activity first increases and then decreases, reaching its highest level at 50 °C. The molecular weight of the resulting polymer shows a decreasing trend. This is because higher polymerization temperatures accelerate chain transfer reactions during polymerization, leading to a decrease in polymer molecular weight. Furthermore, comparing experimental data under dark and light conditions reveals significantly different catalytic behaviors. After light irradiation, the catalyst activity increases, the molecular weight of the resulting polymer increases, and the branching degree decreases. This is because irradiation with 365 nm ultraviolet light transforms the catalyst from the E-form to the Z-form, giving the catalyst a double-layer steric hindrance and potential metal-aryl π interactions. This structural transformation creates a more rigid and compact protective environment around the active metal center, inhibiting chain transfer and chain walking processes such as β-H elimination through steric shielding, and stabilizing key intermediates through metal-aryl π interactions. Therefore, light irradiation increases catalyst activity, increases the molecular weight of the resulting polymer, and decreases the branching degree. Simultaneously, it effectively improves the structural stability of the catalyst at high temperatures and enhances its thermal stability.

[0267] Application Examples 23-32 provide data on the copolymerization of ethylene with polar monomers catalyzed by the α-diimine nickel complex E-(I)-10.

[0268] According to the appendix Figure 3 The UV-Vis absorption spectrum results showed that the α-diimine nickel complex E-(I)-10 exhibited a stable state after irradiation with 365 nm UV light for 450 s, indicating that there was no longer a conversion from the E configuration to the Z configuration. Unlike homopolymerization, copolymerization uses a larger amount of catalyst; therefore, the irradiation time of the catalyst before polymerization was selected to be 24 min.

[0269] In an argon-atmospheric glove box, anhydrous toluene and 0.1–0.2 M polar monomers were added sequentially to a 350 mL thick-walled quartz dish. The dish was then connected to the ethylene gas line, and three ethylene gas replacements were performed. AlEt₂Cl (0.5 mL, 1 M in toluene) was then added. The mixture was preheated at 25 °C and stirred. A 2 mL solution of 10 μmol of the α-diimine nickel complex E-(I)-10 in dichloromethane was then injected. The ethylene pressure was adjusted to 0.2 MPa, and the reaction was stirred for 30 min. After the reaction was complete, 100 mL of acidified ethanol solution (5% HCl in EtOH) was added to quench the reaction. The mixture was stirred at room temperature for 12 h, filtered, and the product was washed several times with ethanol and dried to constant weight. The results are shown in Table 12.

[0270] Table 12

[0271]

[0272] Application Examples 23-32 demonstrate the catalytic performance of catalyst E-(I)-10 in copolymerizing ethylene with polar monomers at 25 °C under ethylene pressure of 0.2 MPa and reaction conditions of 30 min. Experimental results show that both the catalyst activity and the molecular weight of the resulting polymer are increased after light irradiation. This is due to the configurational inversion of the catalyst, which increases the steric hindrance of the metal center. This increased steric hindrance avoids catalyst deactivation caused by coordination of polar monomers and inhibits chain transfer and chain walk processes during polymerization, thereby promoting increased catalyst activity and higher polymer molecular weight. Simultaneously, the existing metal-aryl π-interactions further enhance the catalyst's tolerance to polar monomers, thus increasing the insertion rate of polar monomers under light irradiation.

[0273] It is worth noting that the functionalized polyethylene prepared by copolymerization of ethylene and 4-pentenoic acid exhibits excellent strain recovery properties, with the highest strain recovery rate reaching 93%. Figure 4, 5). Compared with the mechanical properties of ethylene / polar α-olefin copolymers prepared using nickel-based catalysts as reported in the literature, the results obtained in this invention show a level that is comparable to or even superior to those of the present invention.

[0274] This invention introduces photoresponsive groups into olefin polymerization catalysts, enabling dynamic control of the ethylene (co)polymerization process. The complexes prepared by this strategy not only possess high thermal stability but also efficiently catalyze the homopolymerization of ethylene and its copolymerization with polar monomers. The catalytic activity and microstructure of the resulting polymers can be controlled under different light irradiation conditions, achieving simultaneous increases in copolymer molecular weight and polar monomer insertion rate. Simultaneously, polar functionalized polyolefin elastomers can be prepared.

[0275] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A thermally stable, photoresponsive α-diimine nickel complex, with chemical structures of formulas E-(I) and Z-(I): Where R 1 R is one of the following: hydrogen-substituted phenyl, phenyloxy, or phenylthio-substituted phenyl groups. 2 It is one of hydrogen, methyl, isopropyl, tert-butyl, and phenyl. Under 365 nm ultraviolet light irradiation, this complex can change from the trans configuration (E) to the cis configuration (Z); under 405 nm ultraviolet light irradiation, it can change from the cis configuration (Z) to the trans configuration (E).

2. The high thermal stability photoresponsive α-diimine nickel complex according to claim 1, characterized in that, The α-diimine nickel complexes with the chemical structure shown in formula E-(I) include at least one of E-(I)-1 to E-(I)-20:

3. The high thermal stability photoresponsive α-diimine nickel complex according to claim 1, characterized in that, The α-diimine nickel complexes with the chemical structure shown in formula Z-(I) include at least one of Z-(I)-1 to Z-(I)-20:

4. The method for synthesizing the high thermal stability photoresponsive α-diimine nickel complex according to any one of claims 1-3, characterized in that, Includes the following steps: (1) Formula E-1 / Z-1 and compound 5 reacted with a first catalyst at 80~120 °C via a Suzuki coupling reaction to generate a rigid diphenylethylene derivative as shown in Formula E-2 / Z-2; (2) Formula E-2 / Z-2 and compound 6 reacted with the first catalyst at 80~120 °C via Suzuki coupling reaction to generate the aniline derivative shown in Formula E-3 / Z-3; (3) Formula E-3 / Z-3 and compound 7 undergo a condensation reaction at 50~120 °C under the catalysis of the second catalyst to generate α-diimine ligand E-4 / Z-4; (4) Formula E-4 / Z-4 reacts with (DME)NiBr2 at 0~60 °C to generate the α-diimine nickel complex shown in Formula E-(Ⅰ) / Z-(Ⅰ); the reaction route is shown below: Where R 1 R is one of the following: hydrogen-substituted phenyl, phenyloxy, or phenylthio-substituted phenyl groups. 2 It is one of hydrogen, methyl, isopropyl, tert-butyl, and phenyl.

5. The synthesis method according to claim 3, characterized in that, The first catalyst is tetra(triphenylphosphine)palladium or 1,1'-bis(diphenylphosphine)ferrocene palladium(II) dichloride; the second catalyst is zinc chloride or p-toluenesulfonic acid.

6. The synthesis method according to claim 3, characterized in that, The molar ratio of compound E-1 / Z-1 to compound 5 is (1~2):1; the molar ratio of compound E-2 / Z-2 to compound 6 is 1:(1~3); the molar ratio of compound E-3 / Z-3 to compound 7 is (2~5):1; and the molar ratio of compound E-4 / Z-4 to (DME)NiBr2 is 1:(1~5).

7. An application of the high thermal stability photoresponsive α-diimine nickel complex according to any one of claims 1-3 as a catalyst in the catalytic synthesis of polyolefin materials, characterized in that: Compounds containing terminal alkenyl groups are combined with nickel α-diimine complexes of formula E-(I) (concentration 2~40 μmol·L⁻¹). -1 The ethylene homopolymer was carried out in an organic solvent after contacting alkylaluminum reagents. The reaction conditions were: temperature 0~200 ℃, pressure 0.1~3.0 MPa, reaction time 0.05~3.0 h, and the concentration of α-diimine nickel complex E-(I) was 2~40 μmol·L⁻¹. -1 ; Alternatively, a compound containing a terminal alkenyl group, a polar monomer with a terminal double bond, and an α-diimine nickel complex of formula E-(I) (concentration 200~600 μmol·L⁻¹) can be used. -1 When in contact with alkylaluminum reagents, ethylene copolymerization occurs; the reaction conditions are: temperature 0~80 ℃, pressure 0.1~1.0 MPa, reaction time 0.05~3.0 h, and the concentration of α-diimine nickel complex E-(I) is 200~600 μmol·L⁻¹. -1 The concentration of polar monomers with terminal double bonds is 0.05~5.0 M; The polar monomers with terminal double bonds include at least one of methyl acrylate, methyl 10-undecenoate, 4-pentenoic acid, 9-decen-1-ol, and 10-undecenol.

8. The application according to claim 7, characterized in that: Before adding a catalytic amount of a high thermally stable photoresponsive α-diimine nickel complex to the olefin polymerization system, the photoresponsive α-diimine nickel complex E-(I) is irradiated with ultraviolet light with a wavelength of 365 nm.

9. The application according to claim 8, characterized in that: After irradiation with 365 nm ultraviolet light, the α-diimine nickel complex is converted from the E-form to the Z-form, which gives the catalyst a double-layer steric hindrance and potential metal-aryl π interaction. The structural transformation forms a more rigid and compact protective environment around the active metal center. On the one hand, it inhibits chain transfer and chain walking processes through spatial shielding, and on the other hand, it stabilizes key intermediates through metal-aryl π interaction.

10. The application according to claim 7, characterized in that: High thermal stability and photoresponsive α-diimine nickel complexes serve as high-performance catalysts for the copolymerization of ethylene to prepare thermoplastic elastomers, achieving high performance at 150°C. o The catalytic activity of C reaches 0.8 × 10⁻⁶ at high temperatures. 6 g·mol -1 ·h -1 The molecular weight range of the prepared polymers is 15~178×10⁻⁶. 4 g·mol -1 It also exhibits a high elastic recovery rate of 93%.

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