Ligand compound with dual responsiveness, preparation method thereof, catalyst and application

Abstract

The present disclosure provides a ligand compound with dual responsiveness, a preparation method thereof, a catalyst, and an application, belonging to the technical field of organic synthesis. The ligand compound with dual responsiveness includes a structure shown in formula (I): #imgabs0# wherein Ar1 and Ar2 are different from each other and each independently selected from a substituted phenyl group or a substituted naphthyl group. The substituted phenyl group and the substituted naphthyl group each carry at least one ferrocene substituent, an azobenzene substituent, or a cyano substituent, and the substituents of the substituted phenyl group and the substituted naphthyl group are different. In the substituted naphthyl group, the ferrocene substituent, the azobenzene substituent, or the cyano substituent is connected to the naphthyl group via a phenyl group.

Description

Technical Field

[0001] The present disclosure belongs to the technical field of organic synthesis, and particularly relates to a ligand compound with dual responsiveness, a preparation method thereof, a catalyst, and an application. More specifically, it relates to a diimine ligand compound with dual responsiveness, a preparation method, a diimine palladium catalyst, and an application. Background Art

[0002] The strategy of stimulus-responsive regulation of olefin polymerization has developed rapidly. In this strategy, the olefin polymerization process, the microstructure of the polymer, and the properties of the polymer are effectively regulated through external stimulus-regulation means. The above strategy avoids complex chemical synthesis and has a certain degree of generality.

[0003] Although the external stimulus-response regulation strategy has been widely applied in the field of olefin polymerization, it mainly focuses on single-sided stimulus response. There are few reports on using compounds with different stimulus response units in the same catalytic system to achieve the synergistic effect of multiple stimulus response regulations. Summary of the Invention

[0004] In view of the above technical problems, the present disclosure provides a ligand compound with dual responsiveness, a preparation method thereof, a catalyst, and an application, in order to at least partially solve the above technical problems.

[0005] As a first aspect of the present disclosure, there is provided a ligand compound with dual responsiveness, including the structure shown in formula (I):

[0006]

[0007] Wherein, Ar1 and Ar2 are different from each other and each independently selected from a substituted phenyl group or a substituted naphthyl group,

[0008] The substituted phenyl group and the substituted naphthyl group each carry at least one ferrocene substituent, an azobenzene substituent, or a cyano substituent, and the substituents of the substituted phenyl group and the substituted naphthyl group are different,

[0009] In the substituted naphthyl group, the ferrocene substituent, the azobenzene substituent, or the cyano substituent is connected to the naphthyl group via a phenyl group.

[0010] As a second aspect of the present disclosure, there is provided a method for preparing a ligand compound with dual responsiveness, including:

[0011] Reacting compound A Ar1-NH2 with compound B to obtain compound C and then reacting with compound D Ar2-NH2 to obtain the ligand compound shown in formula (I).

[0012] As a third aspect of the present disclosure, a palladium compound is provided, which is obtained by reacting the above ligand compound with a metal palladium precursor;

[0013] Among them, the structure of the palladium compound is shown in formula (II):

[0014]

[0015] As a fourth aspect of the present disclosure, a method for preparing a palladium compound is provided, including:

[0016] Adding a metal palladium precursor to an organic solution of the ligand compound shown in formula (I) for reaction to obtain the palladium compound shown in formula (II);

[0017] Among them:

[0018] The metal palladium precursor includes chloro(1,5-cyclooctadiene)methylpalladium;

[0019] The molar ratio of the ligand compound of formula (I) to the metal palladium precursor is 1:1 to 1:1.2;

[0020] The organic solvent includes dichloromethane.

[0021] As a fifth aspect of the present disclosure, a dual-responsive diimine palladium catalyst is provided, including a palladium cation compound shown in formula (III):

[0022]

[0023] Or an oxide shown in formula (IV):

[0024]

[0025] Among them, the palladium cation compound shown in formula (III) is obtained by reacting the palladium compound shown in formula (II) with sodium tetrakis(3,5-bis(trifluoromethyl)phenyl)borate, and the oxide shown in formula (IV) is obtained by reacting the palladium cation compound shown in formula (III) with silver tetrakis(3,5-bis(trifluoromethyl)phenyl)borate.

[0026] As a sixth aspect of the present disclosure, a method for preparing polyolefin is provided, including:

[0027] Under optional preset conditions, using the above dual-responsive diimine palladium catalyst to catalyze the homopolymerization reaction of olefins; or

[0028] Using the above dual-responsive diimine palladium catalyst to catalyze the copolymerization reaction of olefins and polar monomers;

[0029] Among them, the optional preset conditions include at least one of the following:

[0030] Ultraviolet and visible light illumination, using Lewis acid additives.

[0031] The ligand compound with dual responsiveness provided by the present disclosure, its preparation method, catalyst, and application include one of the following beneficial effects:

[0032] (1) According to the embodiments of the present disclosure, the dual-responsive ligand compound provided by the present disclosure contains two or more different substituents. Different substituents can regulate the electronic effect in the catalyst under external stimuli, thereby achieving different responses. Reacting the ligand compound containing different substituents with a metal palladium ligand to obtain a palladium catalyst, which can be converted into a polymerization-active diimine palladium catalyst and applied to the polymerization reaction of olefins. Since the diimine palladium catalyst contains different stimulus-responsive units, it can regulate the yield, molecular weight, degree of polymerization, etc. of polyolefins under different external stimuli.

[0033] (2) According to the embodiments of the present disclosure, using the ferrocene substituent in the ligand compound, the divalent iron in ferrocene can be converted into trivalent iron under the stimulation of an external oxidant. After oxidation, ferrocene reduces the electron cloud density of the palladium metal center and has stronger electrophilicity; the oxidized ferrocene unit also has reversible reducibility and can be reduced by a reducing agent. Using the azobenzene substituent in the ligand compound, under ultraviolet and visible light irradiation, the π-π* transition of the azobenzene group can achieve the dynamic conversion between the cis and trans structures of the azobenzene unit, changing the steric shielding effect of the palladium metal center, thereby affecting the catalytic activity of the catalyst; and using the cyano substituent in the ligand compound, it can coordinate with an external Lewis acid, and the coordinated group improves the steric shielding effect of the metal center, resulting in a decrease in catalytic activity. By combining the ferrocene substituent, azobenzene substituent, and cyano substituent in different ways, multiple responses under different external stimuli in the same ligand compound can be achieved. Description of the Drawings

[0034] Figure 1A 1H NMR spectrum of compound (2) in Example 1 of the present disclosure;

[0035] Figure 1B 13C NMR spectrum of compound (2) in Example 1 of the present disclosure;

[0036] Figure 2A 1H NMR spectrum of the compound of formula (I) in Example 1 of the present disclosure;

[0037] Figure 2B 13C NMR spectrum of the compound of formula (I) in Example 1 of the present disclosure;

[0038] Figure 3A 1H NMR spectrum of compound (8) in Example 2 of the present disclosure;

[0039] Figure 3B 13C NMR spectrum of compound (8) in Example 2 of the present disclosure;

[0040] Figure 4A 1H NMR spectrum of the compound of formula (II) in Example 2 of the present disclosure;

[0041] Figure 4B 13C NMR spectrum of the compound of formula (II) in Example 2 of the present disclosure;

[0042] Figure 5A 1H NMR spectrum of the compound of formula (III) in Example 3 of the present disclosure;

[0043] Figure 5B 13C NMR spectrum of the compound of formula (III) in Example 3 of the present disclosure;

[0044] Figure 6A 1H NMR spectrum of the compound of formula (IV) in Example 4 of the present disclosure;

[0045] Figure 6B 13C NMR spectrum of the compound of formula (IV) in Example 4 of the present disclosure;

[0046] Figure 7 Schematic diagram of the single crystal structure of the palladium compound shown in formula (IV) in Example 4 of the present disclosure;

[0047] Figure 8 Schematic diagram of the single crystal structure of the palladium compound shown in formula (V) in Example 5 of the present disclosure;

[0048] Figure 9A UV absorption spectrum of the palladium cation compound shown in formula (V) in the present example under 365 nm ultraviolet light irradiation;

[0049] Figure 9B UV absorption spectrum of the palladium cation compound shown in formula (V) in the present example under 420 nm visible light irradiation;

[0050] Figure 9C UV absorption spectrum of the palladium cation compound shown in formula (VII) in the present example under 365 nm ultraviolet light irradiation;

[0051] Figure 9D UV absorption spectrum of the palladium cation compound shown in formula (VII) in the present example under 420 nm visible light irradiation;

[0052] Figure 10Cyclic voltammograms of different compounds shown in Formulas (III) to (VIII) in the embodiments of the present disclosure;

[0053] Figure 11 1H NMR spectrum of the stack of the compound of Formula (V) in the embodiments of the present disclosure;

[0054] Figure 12 Comparison diagram of 1H NMR spectra of the stack before and after the reaction of the ligand compound shown in Formula (II) in the embodiments of the present disclosure with Lewis acid;

[0055] Figure 13 Comparison diagram of 1H NMR spectra of the stack before and after the reaction of the ligand compound shown in Formula (IV) in the embodiments of the present disclosure with Lewis acid. Detailed implementation manners

[0056] To make the objectives, technical solutions and advantages of the present disclosure clearer and more understandable, the present disclosure will be further described in detail below with reference to specific embodiments and the accompanying drawings.

[0057] In recent years, many external stimulus-responsive elements have been developed, including redox, acid / base, light, metal ions, mechanochemistry, electrochemistry, and supramolecular regulation, etc. For example, redox regulation has been applied to multiple catalytic systems to regulate the performance of catalysts by utilizing the different electronic effects of the oxidized state and the reduced state. Lewis acid-base regulation has important applications in both olefin coordination polymerization and ring-opening polymerization fields. It coordinates Lewis acid with the Lewis base in the catalyst, thereby changing the electronic distribution of the metal center and regulating the catalyst performance. Ligands with azobenzene units can change the electronic and steric effects of the catalyst by irradiation with ultraviolet light of a specific wavelength, and then regulate the molecular weight and branching degree of polyethylene. However, catalysts with different catalytic properties of the above regulation strategies can only be obtained from a single catalyst structure, that is, only one stimulus-responsive regulation can be achieved in one catalyst, which limits the flexibility of regulating the synthesis of polyolefins. Therefore, the present disclosure proposes to introduce two or more stimulus-responsive elements into the same catalytic system, and respond through different external stimulus-regulation means in the same compound, realizing the synergistic effect of dual stimulus-responsive regulation.

[0058] Specifically, the first aspect of the present disclosure provides a ligand compound with dual responsiveness, including the structure shown in Formula (I):

[0059]

[0060] Wherein, Ar1 and Ar2 are different from each other and are each independently selected from a substituted phenyl group or a substituted naphthyl group. The substituted phenyl group and the substituted naphthyl group each have at least one ferrocene substituent, an azobenzene substituent or a cyano substituent, and the substituents of the substituted phenyl group and the substituted naphthyl group are different; in the substituted naphthyl group, the ferrocene substituent, the azobenzene substituent or the cyano substituent is connected to the naphthyl group via a phenyl group.

[0061] In an embodiment of the present disclosure, the dual-responsive ligand compound provided in the present disclosure contains two or more different substituents. The different substituents can regulate the electronic effect in the catalyst under external stimuli, thereby achieving different responses. For example: by using the ferrocene substituent in the ligand compound, the divalent iron in ferrocene can be converted into trivalent iron under the stimulation of an external oxidant. After oxidation, ferrocene still has reversible reducibility and can be reduced by a reducing agent. By using the azobenzene substituent in the ligand compound, under the irradiation of external ultraviolet light and visible light, the π-π* transition of the azobenzene group can achieve the dynamic conversion between the cis structure and the trans structure of the azobenzene unit; and by using the cyano substituent in the ligand compound, it can coordinate with an external Lewis acid and can regulate the shielding effect of the metal center, thereby achieving regulation. By combining the ferrocene substituent, the azobenzene substituent and the cyano substituent in different ways, multiple responses under different external stimuli in the same ligand compound can be achieved.

[0062] According to an embodiment of the present disclosure, the substituted phenyl group further includes at least one substituent selected from benzhydryl, isopropyl, methyl, tert-butyl, phenyl; the substituted naphthyl group further includes at least one substituent selected from diphenyl-substituted isopropyl, isopropyl, methyl, tert-butyl, phenyl.

[0063] For example: the ligand compounds shown in the above formula (I) include but are not limited to the following 3 specific compounds:

[0064]

[0065] According to an embodiment of the present disclosure, taking the substituents of the substituted phenyl group as isopropyl and a ferrocene substituent, and the substituent of the substituted naphthyl group as a phenyl group substituted with an azobenzene group as an example for illustration, the specific structure of the ligand compound shown in formula (I) is as shown in formula (I):

[0066]

[0067] According to an embodiment of the present disclosure, taking the substituents of the substituted phenyl group as isopropyl and a ferrocene substituent, and the substituent of the substituted naphthyl group as a phenyl group substituted with a cyano group (benzonitrile group) as an example for illustration, the specific structure of the ligand compound shown in formula (I) can also be as shown in formula (II):

[0068]

[0069] According to an embodiment of the present disclosure, a second aspect of the present disclosure provides a method for preparing a ligand compound with dual responsiveness, including: reacting compound A, Ar1-NH2, with compound B to obtain compound C and then reacting with compound D, Ar2-NH2, to obtain the ligand compound represented by formula (I).

[0070] Specifically, the reaction process for preparing the ligand compound with dual responsiveness is as follows:

[0071]

[0072] According to an embodiment of the present disclosure, the method for preparing the ligand compound with dual responsiveness in the above embodiment includes: adding compound B and an organic acid catalyst to an organic solution of compound A, reacting at a preset temperature to obtain compound C; adding compound C and an organic acid catalyst to an organic solution of compound D in sequence, reacting at a preset temperature to obtain the ligand compound represented by formula (I). Among them, the solvent of the organic solution is selected from: methanol; the organic acid catalyst is selected from any one of formic acid and acetic acid; the preset reaction temperature is 25°C - 80°C, such as 25°C, 40°C, 80°C, etc.; the reaction time is 24h - 48h, such as 24h, 36h, 48h, etc.

[0073] For example: adding compound B and formic acid to a methanol solution of compound A in sequence, reacting at a preset reaction temperature for 48h, filtering and separating the generated solid, washing it three times with methanol, and drying it under vacuum to obtain compound C. Adding compound C and formic acid to a methanol solution of compound D in sequence, reacting at a preset reaction temperature for 48h, filtering and separating the generated solid, dissolving the solid, and separating by column chromatography to obtain the ligand compound represented by formula (I).

[0074] According to an embodiment of the present disclosure, compound B has a molar ratio with compound A, Ar1-NH2, of 3 - 5:1, for example, the molar ratio is 5:1; compound D, Ar2-NH2, has a molar ratio with compound C of 1 - 2:1, for example, the molar ratio is 1.5:1. The excessive compound B and compound D contribute to the formation of the ligand compound represented by formula (I).

[0075] According to an embodiment of the present disclosure, a third aspect of the present disclosure provides a palladium compound, which is obtained by reacting the ligand compound represented by formula (I) in the above embodiment with a metal palladium precursor, wherein the structure of the palladium compound is as shown in formula (II):

[0076]

[0077]

[0078] Specifically, taking the coordination compound of the specific ligand compound shown in formula (I) and palladium metal as an example, the specific structure of the obtained palladium compound is shown in formula (III):

[0079]

[0080] Taking the coordination compound of the specific ligand compound shown in formula (II) and palladium metal as an example, the specific structure of the obtained palladium compound is shown in formula (IV):

[0081]

[0082] It should be noted that: for the ligand compounds shown in formula (I) composed of other substituents, they can also react with the palladium metal precursor to obtain the compounds shown in formula (II).

[0083] According to an embodiment of the present disclosure, a fourth aspect of the present disclosure provides a method for preparing a palladium compound, including: adding a palladium metal precursor to an organic solution of the ligand compound shown in formula (I) for reaction to obtain the palladium compound shown in formula (II); wherein the reaction time is 10 - 12 h, for example, the reaction time can be 10 h, 11 h, 12 h, etc.; the palladium metal precursor includes chloro(1,5 - cyclooctadiene)methylpalladium ((COD)PdMeCl), and the solvent in the organic solution includes dichloromethane; the molar ratio of the ligand compound of formula (I) to the palladium metal precursor is 1:1 to 1:1.2, for example, the molar ratio is 1:1.

[0084] Taking the specific method for preparing the palladium compound shown in the specific structural formula (III) as an example for illustration, the specific preparation method is as follows:

[0085] The method for preparing the palladium compound shown in the specific structural formula (III) includes: in a glove box, adding (COD)PdMeCl to a dichloromethane solution dissolving the compound shown in structural formula (I), and reacting for 10 - 12 h. Then, the solvent is dried under vacuum, and the required compound is separated by column chromatography to obtain an orange solid, that is, the palladium compound shown in structural formula (III), wherein the molar ratio of the ligand compound shown in structural formula (I) to the palladium metal precursor is 1:1.

[0086] According to an embodiment of the present disclosure, the preparation method of the palladium compound shown in formula (IV) is the same as that of the palladium compound shown in formula (III) in the above - mentioned embodiment, and will not be elaborated in detail here.

[0087] According to an embodiment of the present disclosure, a fifth aspect of the present disclosure provides a bis - responsive diimine palladium catalyst, including the palladium cation compound shown in formula (III):

[0088]

[0089] or the oxide represented by formula (IV):

[0090]

[0091] According to an embodiment of the present disclosure, the palladium cation compound represented by formula (III) is obtained by reacting the palladium compound represented by formula (II) with sodium tetrakis(3,5-bis(trifluoromethyl)phenyl)borate (NaBAF).

[0092] Specifically, the specific method for preparing the palladium cation compound represented by formula (III) includes: in a glove box, adding NaBAF to an acetonitrile solution dissolving the palladium compound represented by structural formula (II), and reacting for 10 - 12 h. After removing impurities (sodium chloride) through diatomaceous earth, collecting the filtrate, drying the solvent, adding n-hexane solvent in the glove box, stirring for 10 - 15 min, and filtering to obtain a dark red solid, thus obtaining the compound represented by structural formula (III), wherein the molar ratio of the palladium compound represented by formula (II) to sodium tetrakis(3,5-bis(trifluoromethyl)phenyl)borate (NaBAF) is 1:1 - 1.2, for example, the molar ratio is 1:1; the reaction time is 10 - 12 h, for example, the reaction time is selected from 10 h, 11 h, 12 h, etc.

[0093] For example: taking the reaction of the palladium compound represented by structural formula (III) with NaBAF to obtain the palladium cation compound represented by formula (V) as an example for illustration, wherein the specific palladium cation compound represented by structural formula (V) is as follows:

[0094]

[0095] Furthermore, the preparation method of the palladium cation compound represented by formula (V) includes: in a glove box, adding NaBAF to an acetonitrile solution dissolving the palladium compound represented by structural formula (III), and reacting for 10 - 12 h. After removing impurities (sodium chloride) through diatomaceous earth, collecting the filtrate, drying the solvent, adding n-hexane solvent in the glove box, stirring for 10 - 15 min, and filtering to obtain a dark red solid, namely the palladium cation compound represented by structural formula (V), wherein the molar ratio of the palladium compound represented by structural formula (III) to NaBAF is 1:1.

[0096] Again, for example: taking the reaction of the palladium compound represented by structural formula (IV) with NaBAF to obtain the palladium cation compound represented by formula (VI) as an example for illustration, wherein the specific palladium cation compound represented by structural formula (VI) is as follows:

[0097]

[0098] Furthermore, the method for preparing the palladium cationic compound shown in Formula (VI) includes: in a glove box, adding NaBAF to an acetonitrile solution dissolving the compound shown in Structural Formula (IV), and reacting for 10 - 12 h. After removing impurities (sodium chloride) through diatomaceous earth, collecting the filtrate, drying the solvent, adding n-hexane solvent in the glove box, stirring for 10 - 15 min, and filtering to obtain a dark red solid, which is the palladium cationic compound shown in Structural Formula (VI), wherein the molar ratio of the palladium compound shown in Structural Formula (IV) to NaBAF is 1:1.

[0099] According to an embodiment of the present disclosure, the oxide shown in Formula (IV) is obtained by reacting the palladium cationic compound shown in Formula (III) with silver bis(3,5-bis(trifluoromethyl)phenyl)borate (AgBAF).

[0100] Specifically, the method for preparing the oxide (oxide of the palladium cationic compound) shown in Formula (IV) above includes: in a glove box, adding AgBAF to a dichloromethane solution dissolving the compound shown in Structural Formula (III), and reacting for 1 - 2 h. Filtering through diatomaceous earth to remove the by-product silver chloride, collecting the filtrate, drying the solvent, and directly obtaining a dark red solid, which is the oxide shown in Structural Formula (IV), wherein the molar ratio of the palladium cationic compound shown in Structural Formula (III) to silver bis(3,5-bis(trifluoromethyl)phenyl)borate (AgBAF) is 1:1 - 1.2, for example, the molar ratio is 1:1; the reaction time is 1 - 2 h, for example, the reaction time is 1 h or 2 h.

[0101] For example: Taking the reaction of the palladium cationic compound shown in Structural Formula (V) with AgBAF to obtain the oxide of the palladium cationic compound shown in Formula (VII) (abbreviation "oxide") as an example for illustration, the specific structure of the obtained oxide is as shown in Structural Formula (VII):

[0102]

[0103] Furthermore, the specific method for preparing the oxide shown in Formula (VII) includes: in a glove box, adding AgBAF to a dichloromethane solution dissolving the palladium cationic compound shown in Structural Formula (V), and reacting for 1 - 2 h. Filtering through diatomaceous earth to remove the by-product silver chloride, collecting the filtrate, drying the solvent, and directly obtaining a dark red solid, thereby obtaining the oxide shown in Structural Formula (VII), wherein the molar ratio of the palladium cationic compound shown in Structural Formula (V) to AgBAF is 1:1.

[0104] Another example: Taking the reaction of the palladium cationic compound shown in Structural Formula (VI) with AgBAF to obtain the oxide of the palladium cationic compound shown in Formula (VIII) (abbreviation "oxide") as an example for illustration, the specific structure of the obtained oxide is as shown in Structural Formula (VIII):

[0105]

[0106] Further, the specific method for preparing the oxide shown in Formula (VIII) includes: in a glove box, adding AgBAF to a dichloromethane solution dissolving the palladium cationic compound shown in Structural Formula (VI), and reacting for 1 to 2 h. Filtering off the by-product silver chloride with diatomaceous earth, collecting the filtrate, drying the solvent, and directly obtaining a dark red solid, thus obtaining the oxide shown in Structural Formula (VIII), wherein the molar ratio of the palladium cationic compound shown in Structural Formula (VI) to AgBAF is 1:1.

[0107] According to an embodiment of the present disclosure, a sixth aspect of the present disclosure provides a method for preparing a polyolefin, including: preparing a polyolefin by a polymerization reaction using the diimine palladium catalyst in the above embodiment.

[0108] Specifically, under optional preset conditions, homopolymerization of an olefin is catalyzed by using the diimine palladium catalyst with dual responsiveness in the above embodiment; or copolymerization of an olefin and a polar monomer is catalyzed by using the diimine palladium catalyst with dual responsiveness in the above embodiment; wherein the optional preset conditions include at least one of the following: ultraviolet and visible light illumination, using a Lewis acid additive.

[0109] According to an embodiment of the present disclosure, the reaction temperature is 0 - 60 °C, such as 20 °C, 40 °C, 60 °C, etc.

[0110] According to an embodiment of the present disclosure, the olefins include: ethylene, propylene; the polar monomers include one or more of allylic polar monomers, long-chain polar monomers, norbornene monomers, etc. The allylic polar monomers include, but are not limited to, methyl acrylate; the long-chain polar monomers include, but are not limited to, methyl 10-undecenoate, and the norbornene monomers include, but are not limited to, norbornene.

[0111] According to an embodiment of the present disclosure, the optional preset conditions include at least one of the following: ultraviolet and visible light illumination, using a Lewis acid additive.

[0112] According to an embodiment of the present disclosure, in the case where the diimine palladium catalyst with dual responsiveness (i.e., the compounds shown in Formulas (III) and (IV)) contains an azobenzene substituent, when irradiated with light of 365 nm, due to the π-π* transition of the azobenzene group, the compounds shown in Formulas (III) and (IV) have a strong absorption value at 365 nm. As time changes, the π-π* absorption of the trans isomers of the compounds shown in Formulas (III) and (IV) gradually decreases, indicating the formation of cis isomers; when irradiated with a light source of 420 nm wavelength, the compounds shown in Formulas (III) and (IV) are converted from the cis structural isomers to trans isomers again.

[0113] According to an embodiment of the present disclosure, in the case where a cyanide substituent is contained in a diimine palladium catalyst having dual responsiveness (i.e., a compound represented by Formula (III) or Formula (IV)), the cyanide substituent can coordinate with a Lewis acid additive, thereby enabling a polymerization reaction of polyolefins to occur, wherein the Lewis acid additive can be selected from tris(pentafluorophenyl)borane (B(C6F5)3).

[0114] The following specifically describes in detail the ligand compound having dual responsiveness provided by the present disclosure, its preparation method, catalyst, and application in conjunction with specific examples and drawings.

[0115] Example 1

[0116] The reaction route for synthesizing Compound (2) used for preparing the ligand compound shown in Reaction Scheme (I) is as shown in Formula (IX):

[0117]

[0118] The specific method for synthesizing Compound (2) includes: at -20 °C under N2 conditions, adding a hexane solution of n-butyllithium (12.0 mL, 2.5 M, 30 mmol) to a tetrahydrofuran (100 mL) solution of ferrocene (2.23 g, 12 mmol), stirring for 1 h, warming to room temperature and stirring for 1 h, adding a tetrahydrofuran (10 mL) solution of ZnCl2 (1.63 g, 12 mmol) and stirring for 1 h, adding a tetrahydrofuran (10 mL) solution of 2,6-diisopropyl-4-bromoaniline (2.23 g, 10 mmol) and Pd(PPh3)4 (116 mg, 1 mmol), warming to 90 °C, and reacting for 12 h. Filter to remove insolubles, extract with ethyl acetate, dry over Na2SO4, and separate by column chromatography to obtain Compound (1). Compound (1) (1.80 g, 5.0 mmol), 2,3-butanedione (2.15 g, 25.0 mmol), a catalytic amount of formic acid, and methanol (50 mL) were charged into a 100 mL round-bottom flask. After stirring at 40 °C for 24 h, the resulting solid was separated by filtration, washed three times with methanol, and dried under vacuum to obtain the orange solid Compound (2) (1.70 g, 78%).

[0119] The structure of Compound (2) was characterized by 1 1H NMR spectrum, 13 13C NMR spectrum, and the specific characterization results are as shown in Figure 1A , Figure 1B .

[0120] 11H NMR (400 MHz, C6D6) δ 7.45 (s, 2H), 4.58 (t, J = 1.6 Hz, 2H), 4.16 (t, J = 1.6 Hz, 2H), 3.99 (s, 5H), 2.65 - 2.52 (m, 2H), 2.40 (s, 3H), 1.74 (s, 3H), 1.14 (dd, J = 16.0, 8.0 Hz, 12H).

[0121] 13 13C NMR (101 MHz, C6D6) δ 197.65, 166.18, 142.80, 134.57, 133.71, 120.78, 86.44, 68.75, 67.73, 66.01, 27.60, 23.44, 22.18, 21.61, 13.89. HRMS (m / z): Calcd for C26H 31 FeNO: 429.3930, Found: 429.2035 [M + H].

[0122] The reaction route for synthesizing compound (3) is shown in Scheme (X):

[0123]

[0124] The specific method for synthesizing compound (3) includes: Under N2 atmosphere, 1-naphthylamine (1.43 g, 10 mmol), 2-pyridinecarboxylic acid (1.35 g, 11 mmol), 4-(methylamino)pyridine (122 mg, 1 mmol) were stirred and dissolved in dichloromethane. At 0 °C, a dichloromethane solution of N,N'-dicyclohexylcarbodiimide (2.10 g, 11 mmol) was added, and the mixture was stirred at room temperature for 12 h. The insoluble substances were filtered off, the mixture was extracted with water, dried over Na2SO4, concentrated, and separated by column chromatography to obtain the target compound (3).

[0125] The reaction route for synthesizing compound (4) is shown in Scheme (XI):

[0126]

[0127] The specific method for synthesizing compound (4) includes: Under N2 atmosphere, 4-iodoaniline (0.219 g, 1.00 mmol), nitrobenzene (0.107 g, 1.00 mmol) and acetic acid (2.00 mL) were stirred for 24 h, and the target compound (4) (0.276 g, 90%) was obtained as an orange solid by column chromatography separation.

[0128] The reaction route for synthesizing compound (6) is shown in Scheme (XII):

[0129]

[0130] The specific method for synthesizing compound (6) includes: under N2 condition, reacting a mixture of compound (3) (6.7 g, 27 mmol), compound (4) (24.1 g, 81 mmol), AgOAc (6.7 g, 40.5 mmol), and Pd(OAc)2 (160 mg, 0.68 mmol) at 140 °C for 24 h, and separating by column chromatography to obtain compound (5). Reacting compound (5) (6.4 g, 15 mmol) in NaOH solution (6.0 g NaOH, 150 mmol in EtOH / H2O, 10 / 1, v / v, 60 mL) by refluxing for 12 h. After the reaction, separating by column chromatography to obtain the target compound (6).

[0131] The specific route for synthesizing the compound shown in formula (I) from compound (2) and compound (6) is as shown in formula (XIII):

[0132]

[0133] The specific method for synthesizing the ligand compound shown in formula (I) includes: loading compound (2) (4.30 g, 10.0 mmol), compound (6) (3.23 g, 10.0 mmol), a catalytic amount of formic acid and methanol (50 mL) into a 100 mL round-bottom flask. Stirring the resulting suspension at 40 °C for 48 h. Separating the resulting solid by filtration, dissolving the residue in dichloromethane and performing column chromatography to obtain an orange solid as the ligand compound shown in formula (I) (4.10 g, 56%).

[0134] The structure of the ligand compound shown in formula (I) was characterized by 1 1H NMR spectrum, 13 13C NMR spectrum, as shown in Figure 2A 、 Figure 2B shown.

[0135] 1 1H NMR (400 MHz, CD2Cl2) δ 8.04–7.87 (m, 5H), 7.79 (d, J = 8.2 Hz, 1H), 7.53 (m, 7H), 7.32 (d, J = 7.1 Hz, 1H), 7.16 (s, 2H), 6.76 (d, J = 7.3 Hz, 1H), 4.54 (s, 2H), 4.24 (s, 2H), 4.01 (s, 5H), 2.51–2.36 (m, 2H), 2.05 (s, 3H), 1.36 (s, 3H), 1.11 (dd, J = 16.0, 8.0 Hz, 12H).

[0136] 1313C NMR (101 MHz, CD2Cl2) δ 168.56, 166.94, 153.05, 151.64, 148.52, 148.05, 144.93, 138.88, 135.97, 135.12, 134.28, 131.49, 130.42, 129.61, 129.20, 126.59, 125.75, 125.40, 124.07, 123.40, 122.46, 121.69, 115.99, 87.89, 69.94, 68.84, 66.99, 28.64, 23.37, 23.17, 16.79, 15.64, 1.33. HRMS (m / z): Calcd for C 48 H 46 FeN4: 734.7703 Found: 733.9504 [M+H].

[0137] Example 2

[0138] The synthetic route of compound (8) is shown in Formula (XIV):

[0139]

[0140] The specific method for synthesizing compound (8) includes: adding 8-bromonaphthalen-1-amine (2.22 g, 10.0 mmol), 4-cyanophenylboronic acid (1.76 g, 12.0 mmol), Pd(dppf)Cl2 (366 mg, 0.5 mmol), K3PO4·H2O (8.0 g, 30.0 mmol) and DMSO (50 mL) into a 100 mL Schlenk flask respectively. After stirring at 95 °C for 12 h, the insoluble substances were filtered off, extracted with ethyl acetate, washed 3 times with saturated brine, dried over Na2SO4, concentrated, and the crude product was further purified by column chromatography to obtain a light red solid compound (8) (1.3 g, 55%).

[0141] The structure of compound (8) was characterized by 1 1H NMR spectrum, 13 13C NMR spectrum, as shown in Figure 3A , Figure 3B shown.

[0142] 11H NMR (400 MHz, CDCl3) δ 7.84 (d, J = 8.2 Hz, 1H), 7.74 (d, J = 8.1, 1.7 Hz, 2H), 7.58 (d, J = 8.2, 1.6 Hz, 2H), 7.46 - 7.37 (m, 2H), 7.33 (t, J = 7.8, 1.6 Hz, 1H), 7.14 (d, 1H), 6.73 (d, J = 7.3, 1.5 Hz, 1H), 3.36 (s, 2H).

[0143] 13 13C NMR (101 MHz, CDCl3) δ 148.35, 142.95, 136.37, 135.92, 131.77, 130.25, 129.81, 128.56, 127.02, 124.70, 120.27, 119.77, 118.88, 112.23, 111.39. HRMS (m / z): Calcd for C 17 H 12 N2: 244.2970, Found: 245.1066 [M + H].

[0144] The route for synthesizing the ligand compound shown in Formula (II) from Compound (2) and Compound (8) is shown in Formula (XV):

[0145]

[0146] The specific method for synthesizing the ligand compound shown in Formula (II) includes: adding Compound (2) (4.30 g, 10.0 mmol) and Compound (8) (2.44 g, 10.0 mmol) into a 100 mL round-bottom flask, along with a catalytic amount of formic acid and methanol (40 mL). The resulting suspension is stirred at 40 °C for 48 hours. The solid produced is separated by filtration, and the residue is dissolved in dichloromethane and purified by column chromatography to obtain an orange solid, which is the ligand compound shown in Formula (II) (3.80 g, 58%).

[0147] The structure of the ligand compound shown in Formula (II) was characterized by 1 1H NMR spectrum, 13 13C NMR spectrum, as shown in Figure 4A , Figure 4B .

[0148] 11H NMR (400 MHz, C6D6) δ 7.37 (d, J = 8.3, 1.3 Hz, 1H), 7.21 (d, 1H), 6.92 (q, 2H), 6.86 (s, 1H), 6.74 (d, J = 8.0 Hz, 2H), 6.58 (d, 2H), 6.16 (d, J = 7.3, 1.2 Hz, 1H), 4.31 (s, 2H), 3.87 (s, 2H), 3.73 (s, 5H), 2.41–2.27 (m, 2H), 1.66 (s, 3H), 1.11 (d, J = 6.9 Hz, 6H), 1.07 (s, 3H), 0.97 (d, J = 6.8 Hz, 6H).

[0149] 13 13C NMR (101 MHz, C6D6) δ 168.19, 166.64, 149.06, 148.07, 144.96, 137.79, 135.84, 135.22, 134.93, 131.00, 130.14, 129.98, 129.52, 127.94, 126.57, 125.37, 125.34, 123.74, 122.08, 118.90, 116.02, 110.84, 88.06, 69.96, 68.84, 67.29, 28.92, 23.45, 23.13, 16.48, 15.38. HRMS (m / z): Calcd for C 43 H 41 FeN3: 655.6670, Found: 655.3706.

[0150] Example 3

[0151] The route for synthesizing the palladium compound shown in Formula (III) is as shown in Formula (XVI):

[0152]

[0153] The specific method for synthesizing the palladium compound shown in Formula (III) includes: adding the ligand compound shown in Formula (I) (735 mg, 1.0 mmol), (COD)PdMeCl (265 mg, 1 mmol) (COD = 1,2-dimethoxyethane) and dichloromethane (20 mL) into a 50 mL Schlenk flask. After stirring at room temperature for 12 hours. During the stirring process, the solid completely dissolves and the color of the solution changes from orange to dark red. At the end of the reaction, the solvent is removed under vacuum and the desired compound is separated by column chromatography. The product is a dark red solid compound, the palladium compound shown in Formula (III) (674 mg, 83%).

[0154] The structure of the palladium compound shown in Formula (III) was characterized by 1 1H NMR spectrum,13 Characterized by 13C NMR spectrum, such as Figure 5A , Figure 5B shown.

[0155] 1 1H NMR (400 MHz, CD2Cl2) δ 8.26 - 8.19 (m, 2H), 8.04 - 7.94 (m, 5H), 7.69 - 7.65 (m, 1H), 7.62 - 7.55 (m, 5H), 7.48 (dd, J = 8.0, 4.0 Hz, 1H), 7.37 (dd, J = 8.0, 1.2 Hz, 1H), 7.30 (dd, J = 8.0, 1.2 Hz, 1H), 7.26 (d, J = 4.0 Hz, 1H), 7.20 (d, J = 4.0 Hz, 1H), 4.59 (m, 2H), 4.29 (t, J = 2.0 Hz, 4H), 2.97 (m, 2H), 2.21 (m, 2H), 1.89 (s, 3H), 1.72 (s, 3H), 1.36 - 0.80 (m, 12H), 0.44 (s, 3H).

[0156] 13 13C NMR (101 MHz, CD2Cl2) δ 175.61, 168.05, 152.90, 152.03, 146.46, 143.47, 140.01, 139.46, 139.15, 138.92, 138.01, 135.37, 134.17, 131.85, 131.79, 129.76, 129.63, 128.74, 128.66, 128.58, 126.14, 125.67, 125.16, 124.56, 123.57, 122.23, 122.14, 122.11, 120.38, 85.71, 70.09, 70.01, 69.48, 67.15, 67.08, 28.61, 28.13, 24.34, 23.88, 23.77, 23.40, 21.23, 20.96. MALDI - TOF (m / z): Calculated value: C 49 H 49 ClFeN4Pd: 891.6740, Measured value: 839.2481 [M - Cl - Me - H] + . Analyzed calculated value of C 49 H 49 ClFeN4Pd: C, 66.00; H, 5.54; N, 6.28; Measured value: C, 66.05; H, 5.50; N, 6.31.

[0157] Example 4

[0158] The method for preparing the palladium compound shown in Formula (IV) is the same as the specific method for the palladium compound shown in Formula (III), where the yield of the palladium compound shown in Formula (IV) is 644 mg, 78%.

[0159] The structure of the palladium compound shown in Formula (IV) was characterized by 1 1H NMR spectrum,[[]]END]] 13 13C NMR spectrum, as Figure 6A Figure 6B shown.

[0160] 1 1H NMR (400 MHz, CDCl3) δ 8.25 (d, J = 8.0 Hz, 1H), 8.04 - 7.86 (m, 3H), 7.68 (s, 2H), 7.58 - 7.48 (m, 2H), 7.43 (d, J = 7.0 Hz, 1H), 7.28 (s, 2H), 4.63 (s, 2H), 4.33 (s, 1H), 4.04 (s, 5H), 3.00 - 2.86 (m, 1H), 2.30 - 2.16 (m, 1H), 1.72 (s, 4H), 1.52 (d, J = 6.7 Hz, 3H), 1.35 (d, J = 6.5 Hz, 3H), 1.26 (d, J = 7.0 Hz, 5H), 1.05 (d, J = 6.6 Hz, 3H), 0.61 (s, 3H).

[0161] 13 13C NMR (101 MHz, CDCl3) δ 174.62, 167.37, 147.49, 142.24, 139.50, 138.93, 138.75, 138.65, 136.05, 134.95, 134.58, 132.25, 131.78, 131.20, 130.23, 128.58, 127.37, 125.81, 125.73, 123.52, 122.59, 122.10, 122.06, 119.39, 110.95, 85.35, 69.79, 69.17, 66.94, 66.89, 28.30, 28.20, 24.20, 24.10, 23.81, 23.38, 21.01, 20.36, 3.16, 1.16. MALDI-TOF (m / z): Calculated for C 44 H 44 ClFeN3Pd: 812.5720, Found: 760.4626 [M-Cl-Me-H] + , Analytically calculated for C 44 H 44ClFeN3Pd: C, 65.04; H, 5.46; N, 5.17; Test values: C, 65.01; H, 5.42; N, 5.14.

[0162] Figure 7 This is a schematic diagram of the single crystal structure of the palladium compound shown in Formula (IV) in Example 4 of the present disclosure.

[0163] As Figure 7 shown in the single crystal structure diagram, it intuitively reflects the correctness of the structure of the compound shown in Formula (IV), and indicates the spatial structure of the compound, that is, the relative positions of the atoms.

[0164] Example 5

[0165] The synthetic route of the palladium cationic compound shown in Formula (V) is as shown in Formula (XVII):

[0166]

[0167] The specific method for synthesizing the palladium cationic compound shown in Formula (V) includes: adding NaBAF (886 mg, 1.0 mmol) and the palladium compound shown in Formula (III) (892 mg, 1.0 mmol) to a Schlenk flask under a nitrogen atmosphere. Acetonitrile (15 mL) was added to form a bright orange solution, and the mixture was stirred overnight. The solution was passed through diatomaceous earth to remove the white NaCl precipitate. The volatile substances were dried by suction to obtain a dark red solid, the palladium cationic compound shown in Formula (V) (861 mg, 96%).

[0168] Figure 8 This is a schematic diagram of the single crystal structure of the palladium cationic compound shown in Formula (V) in Example 5 of the present disclosure.

[0169] As Figure 8 shown in the single crystal structure diagram, it intuitively reflects the correctness of the structure of the compound shown in Formula (V), and indicates the spatial structure of the compound, that is, the relative positions of the atoms.

[0170] Example 6

[0171] The preparation method of the palladium cationic compound shown in Formula (VI) is the same as that of the palladium cationic compound shown in Formula (V).

[0172] Example 7

[0173] The synthetic route of the oxide shown in Formula (VII) is as shown in Formula (XVIII):

[0174]

[0175] The specific method for synthesizing the oxide shown in formula (VII) includes: adding compound of formula (V) (176 mg, 0.1 mmol), AgBAF (95.1 mg, 0.1 mmol) and 10 mL of CH2Cl2 into a 50 mL Schlenk flask. Stir for 1 h, filter with diatomaceous earth to remove the silver precipitate, and after vacuum drying, obtain the oxide shown in formula (VII) (160 mg, 91%), which is directly used for polymerization and copolymerization without further purification.

[0176] Example 8

[0177] The preparation method of the oxide shown in formula (VIII) is the same as that of the oxide shown in formula (VII), and will not be elaborated here.

[0178] Figure 9A This is the ultraviolet absorption spectrum of the palladium cationic compound shown in formula (V) in the present disclosure example under 365 nm ultraviolet light irradiation; Figure 9B This is the ultraviolet absorption spectrum of the palladium cationic compound shown in formula (V) in the present disclosure example under 420 nm visible light irradiation; Figure 9C This is the ultraviolet absorption spectrum of the palladium cationic compound shown in formula (VII) in the present disclosure example under 365 nm ultraviolet light irradiation; Figure 9D This is the ultraviolet absorption spectrum of the palladium cationic compound shown in formula (VII) in the present disclosure example under 420 nm visible light irradiation.

[0179] As Figure 9A 、 Figure 9C It can be seen from the ultraviolet absorption spectra shown that under ultraviolet light irradiation, due to the π-π * transition of the azobenzene group, as time changes, the π-π * absorption of the trans isomers of the compounds shown in formula (V) and formula (VII) decreases, indicating the formation of cis isomers. When irradiated with visible light at a wavelength of 420 nm, as time changes, the π-π * absorption of the trans isomers of the compounds shown in formula (V) and formula (VII) increases, and the compounds shown in formula (V) and formula (VII) are isomerized from the cis structure to the trans structure again, as Figure 9B 、 Figure 9D shown.

[0180] According to the embodiments of the present disclosure, the present disclosure explores the redox ability of the compounds shown in formula (III) - formula (VIII), and the specific test results are shown in Table 1 and Figure 10 shown:

[0181] Table 1. Comparison of cyclic voltammetry data of AgBAF and the compounds shown in formula (III) - formula (VIII) in the present disclosure examples

[0182] Compound <![CDATA[Ep A / V]]> <![CDATA[Ep C / V]]> <![CDATA[E 1 / 2 / V]]> <![CDATA[AgBAF b > 0.960 0.620 0.790 Pd-Cl-1 0.788 0.540 0.664 Pd1 0.817 0.557 0.687 <![CDATA[Pd1 + > 0.771 0.573 0.672 Pd-Cl-2 0.674 0.298 0.486 Pd2 0.635 0.380 0.508 Pd2 0.587 0.366 0.478

[0183] Among them: Pd-Cl-1 represents the palladium compound shown in formula (III), Pd1 represents the palladium cationic compound shown in formula (V), Pd1 + represents the oxide shown in formula (VII), Pd-Cl-2 represents the palladium compound shown in formula (IV), Pd2 represents the palladium cationic compound shown in formula (VI), Pd1 + represents the oxide shown in formula (VIII).

[0184] As can be seen from the data in Table 1, the E l / 2 value of AgBAF is greater than the El / 2 value of the compounds shown in formula (V) and formula (VI), indicating that AgBAF can be used as an oxidant for the compounds shown in formula (V) and formula (VI) to oxidize them to form the oxides of formula (VII) and formula (VIII).

[0185] Figure 10 This is the cyclic voltammogram of different compounds shown in formula (III) to formula (VIII) in the embodiments of the present disclosure.

[0186] As Figure 10 shown, different compounds shown in formula (III) to formula (VIII) all have quasi-reversible oxidation-reduction peaks, indicating that the palladium catalysts shown in formula (III) to formula (VIII) can all reversibly undergo oxidation-reduction reactions, where Figure 10 (a) to (f) therein correspond to different compounds shown in formula (III) to formula (VIII) in sequence.

[0187] Furthermore, the present disclosure conducts an external stimulus regulation experiment on the oxidation-reduction of the palladium cationic compound shown in formula (V), and the specific experimental test results are as Figure 11 shown.

[0188] Figure 11 This is the 1H nuclear magnetic resonance spectrum of the stacking of the compound shown in formula (V) in the embodiments of the present disclosure.

[0189] As Figure 11 shown in (a) and (b) therein, through the nuclear magnetic resonance test experiment on the palladium cationic compound shown in formula (V), the experimental results show that adding 1 equivalent of AgBAF oxidant to the palladium cationic compound shown in formula (V) will cause the nuclear magnetic resonance signal to completely disappear. After adding the reducing agent Cp2Co, the nuclear magnetic resonance signal reappears ( Figure 11 in (c) therein). This experimental result shows that after adding the AgBAF oxidant, ferrocene (Fc) is oxidized, and iron changes from divalent to trivalent. Therefore, Fe has paramagnetism, resulting in the disappearance of the peaks in the 1H nuclear magnetic resonance spectrum; while after adding the reducing agent Cp2Co, the paramagnetic trivalent iron is reduced, and the peaks in the nuclear magnetic resonance spectrum can reappear. Among them, Pd1 represents the palladium cationic compound of formula (V), Pd1 + 1eq.AgBAF represents adding 1 equivalent of AgBAF oxidant to the compound shown in formula (V), Pd+ Adding 1 equivalent of the reducing agent Cp2Co to the oxide shown in formula (VII).

[0190] Figure 12 Stacked 1H NMR spectra comparison of the ligand compound shown in formula (II) before and after adding Lewis acid in the embodiments of the present disclosure.

[0191] As Figure 12 (a) in is the 1H NMR spectrum of the ligand compound shown in formula (II), Figure 12 (b) in is the 1H NMR spectrum after adding 1 equivalent of the small borane Lewis acid (B(C6F5)3) to the ligand compound shown in formula (II). From (a) and (b), it can be seen that after adding 1 equivalent of the small borane Lewis acid (B(C6F5)3) to the ligand compound shown in formula (II), the two singlets of the methyl groups on the ligand compound skeleton shown in formula (II) are shifted from 1.35 ppm and 1.95 ppm to 1.70 ppm and 2.37 ppm, shifting to a lower field, which is consistent with the inference that after adding the small borane, the electron cloud density of the ligand decreases and the characteristic peak shifts to a lower field. Among them, L2 represents the ligand compound shown in formula (II), and L2 + 1eq.(B(C6F5)3 represents adding 1 equivalent of the small borane Lewis acid to the ligand compound shown in formula (II).

[0192] Figure 13 Stacked 1H NMR spectra comparison of the ligand compound shown in formula (IV) before and after adding Lewis acid in the embodiments of the present disclosure.

[0193] Figure 13 (a) in is the 1H NMR spectrum of the palladium compound shown in formula (IV), Figure 13 (b) in is the 1H NMR spectrum after adding 1 equivalent of the small borane Lewis acid (B(C6F5)3) to the ligand palladium compound shown in formula (IV). From Figure 13 (a) and (b) in, it can be seen that after adding 1 equivalent of the small borane Lewis acid (B(C6F5)3) to the palladium compound shown in formula (IV), some of the original characteristic peaks of the compound shown in formula (IV) have shifted to varying degrees, and the active hydrogens on the palladium compound shown in formula (IV) and the small borane ligand have broadened, which also indicates the coordination effect of the added small borane on the catalyst. Among them, Pd-Cl-2 represents the palladium compound shown in formula (IV), and Pd-Cl-2 + 1eq.(B(C6F5)3 represents the ligand after adding 1 equivalent of the small borane Lewis acid to the palladium compound shown in formula (IV).

[0194] According to the embodiments of the present disclosure, there is also provided a polymerization reaction of olefins catalyzed by the compounds in the above embodiments, wherein the polymerization reaction includes a homopolymerization reaction and a copolymerization reaction of an olefin and a polar monomer.

[0195] Example 9

[0196] The method for the homopolymerization of olefins includes: in a glove box, under a nitrogen atmosphere, 18 mL of dichloromethane is added to the pressure-resistant bottle of a 350 mL autoclave (equipped with a magnetic stirring device, an oil bath heating device, and a thermometer). The container is connected to a high-pressure pipeline and the pipeline is evacuated. The container is controlled at an appropriate temperature using a water bath, and a certain amount of the palladium catalyst prepared in Example 2 dissolved in 2 mL of dichloromethane is injected into the polymerization system through a syringe. The valve is closed, and after adjusting the ethylene pressure to 8 atmospheres, the reaction is carried out for 2 hours. The reaction is stopped, the autoclave is opened, and the obtained polymer is dried under vacuum to remove the solvent to obtain a yellow oil. Through testing, the results of the homopolymerization of olefins catalyzed by different palladium compound catalysts in the above examples are shown in Table 2 below:

[0197] Table 2. Influence of different palladium compound catalysts on the catalytic homopolymerization of ethylene under different reaction conditions

[0198]

[0199] The polymerization reaction conditions in Table 2 are: Pd catalyst = 10 μmol, reaction time = 2 h, dichloromethane (DCM) = 20 mL, ethylene pressure = 8 atm. Among them, the polymerization is repeated at least 2 times or more. PDI represents the polymer dispersity index, b Activity = 10 4 g·mol -1 ·h -1 . c The molecular weight measurement is carried out by GPC at 25 °C using tetrahydrofuran as the solvent. Using 1 1H NMR analysis to determine the branching degree (B d ) of polyethylene; the light conditions (Light) include darkness (Dark) and ultraviolet and visible light irradiation (UV-Vis); among them, Pd1 represents the palladium cationic compound shown in formula (V), and Pd1 + represents the oxide shown in formula (VII).

[0200] By comparing the data in the first row and the second row of Table 2, under ultraviolet and visible light irradiation, in the homopolymerization of ethylene catalyzed by the compound shown in formula (V), the polymerization activity (Act) of the polymer decreases, but the polymer molecular weight (M n ) increases. It can be seen that when irradiated with ultraviolet-visible light, the compounds shown in formula (V) and formula (VII) undergo trans-cis isomerization, increasing the steric shielding effect of the metal center and making it more difficult for β-H elimination to occur, that is, reducing the chain transfer efficiency, so the activity decreases and the polymer molecular weight increases.

[0201] By comparing the data in the 1st row and the 3rd row of Table 2, in the ethylene homopolymerization reaction catalyzed by the compound shown in Formula (V) after being oxidized by AgBAF, the yield of the polymer decreases, the polymerization activity (Act) of the polymer decreases, and the molecular weight (M n ) of the polymer also decreases. It can be seen that the electron-withdrawing effect of the ferrocene unit after oxidation is stronger, which reduces the electron cloud density of the palladium metal center, making it more electrophilic. The β-H elimination is more likely to occur during the polymerization process, that is, the chain transfer rate is increased, so the activity is reduced and the molecular weight of the obtained polymer is reduced. In other words, when AgBAF is added, the ferrocene unit in the compounds shown in Formulas (V) and (VII) is oxidized, and the electron-withdrawing effect of the oxidized ferrocene unit is stronger, which reduces the electron cloud density of the palladium metal center, making it more electrophilic. The β-H elimination is more likely to occur during the polymerization process.

[0202] By comparing the data in the 1st row and the 4th row of Table 2, after being oxidized by AgBAF and under ultraviolet-visible light irradiation, in the ethylene homopolymerization reaction catalyzed by the compound shown in Formula (V), the yield (Yield) of the polymer decreases, and the decrease in the polymerization activity (Act) of the polymer is greater. The molecular weight (M n ) of the polymer increases slightly. However, by comparing the data in the 5th row and the 8th row, at 20 °C, the molecular weight (M n ) of the polymer decreases. It can be seen that at 0 °C, the photo-regulation plays a dominant role, and at 20 °C, the redox regulation plays a dominant role. In other words, when irradiated with 365 nm ultraviolet light, the compounds shown in Formulas (V) and (VII) undergo a rapid trans-cis isomerization conversion, which increases the steric shielding effect of the palladium metal center, that is, increases the steric hindrance of the metal center. The β-H elimination is less likely to occur during the polymerization process, that is, the chain transfer efficiency is reduced, resulting in a decrease in activity and an increase in the molecular weight of the polymer.

[0203] Table 3 shows the influence of different compounds coordinated with small borane Lewis acids on the catalytic ethylene homopolymerization reaction

[0204]

[0205] The polymerization reaction conditions in Table 3 are: Pd catalyst = 10 μmol, reaction time = 2 h, DCM = 20 mL, ethylene pressure = 8 atm. Among them, the polymerization is repeated at least 2 times. b Activity = 10 4 g·mol -1 ·h -1 . c The molecular weight was measured by GPC at 25 °C using tetrahydrofuran as the solvent. The degree of branching of polyethylene was determined by 1 1H NMR analysis; among them, Pd2 represents the compound shown in Formula (VI); Pd2 +The compound represented by formula (VIII).

[0206] By comparing the data in the first row and the second row of Table 3, after being oxidized by AgBAF, in the ethylene homopolymerization reaction catalyzed by the compound represented by formula (VI), the yield of the polymer and the polymerization activity (Act) decrease, and the molecular weight of the polymer (M n ) decreases. It can be seen that the electron-withdrawing effect of the oxidized ferrocene unit is stronger, which reduces the electron cloud density of the palladium metal center, making it more electrophilic. The β-H elimination is more likely to occur during the polymerization process, that is, the chain transfer rate is increased, so the activity is reduced and the molecular weight of the obtained polymer is reduced.

[0207] By comparing the data in the first row and the third row of Table 3, after adding small borane (B(C6F5)3), in the ethylene homopolymerization reaction catalyzed by the compound represented by formula (VI), the yield of the polymer and the polymerization activity (Act) decrease, but the molecular weight of the polymer (M n ) increases. The main reason is as follows: Combining the above single crystal structure, it can be seen that the distance between the palladium metal center and the cyano group is relatively close. After the small borane coordinates with the cyano unit, the steric shielding effect of the metal center will be improved, resulting in a decrease in activity and an increase in the molecular weight of the polymer.

[0208] By comparing the data in the first row and the fourth row of Table 3, after being oxidized by AgBAF and irradiated with ultraviolet-visible light, in the ethylene homopolymerization reaction catalyzed by the compound represented by formula (VI), the decrease in the yield of the polymer and the polymerization activity (Act) is greater, and the molecular weight of the polymer (M n ) also decreases. It can be seen that the redox regulation plays a dominant role.

[0209] Example 10

[0210] The method for copolymerization of an olefin and a polar monomer includes: in a glove box, under a nitrogen atmosphere, a certain amount of dichloromethane and a polar monomer are added to the pressure-resistant bottle of a 350 mL autoclave (equipped with a magnetic stirring device, an oil bath heating device and a thermometer). The container is connected to a high-pressure pipeline and the pipeline is evacuated. The container is controlled at an appropriate temperature using a water bath, and a certain amount of the palladium catalyst prepared in the example dissolved in 2 mL of dichloromethane is injected into the polymerization system through a syringe. The valve is closed, the ethylene pressure is adjusted to 8 atmospheres, and the reaction is carried out for 2 hours. The reaction is stopped, the reaction kettle is opened, and the obtained polymer is dried under vacuum to obtain a yellow oil. Through testing, the results of the copolymerization reaction of olefins and polar monomers catalyzed by different palladium compound catalysts in the above examples are shown in Table 4 below:

[0211] Table 4. Effects of different compounds on the copolymerization reaction of ethylene with different polar monomers

[0212]

[0213] The polymerization reaction conditions in Table 4 are as follows: Pd catalyst = 10 μmol, reaction time = 2 h, DCM = 20 mL, ethylene pressure = 8 atm, total volume of dichloromethane and polar monomer = 20 mL, time = 2 h. Among them, the polymerization is repeated at least 2 times or more. b Activity = 10 4 g·mol -1 ·h -1 , c The molecular weight was measured by GPC using tetrahydrofuran as the solvent at 25 °C. d The insertion ratio of the polar monomer was determined by 1 1H NMR; among them, Pd1 represents the compound shown in Formula (V); Pd1 + represents the compound shown in Formula (VII), MUA represents methyl 10-undecenoate, NB represents norbornene, and MA represents methyl acrylate.

[0214] By comparing the data in the first row and the second row of Table 4, in the copolymerization reaction of ethylene and polar monomer catalyzed by the compound shown in Formula (V) under ultraviolet-visible light irradiation, the yield of the polymer and the polymerization activity (Act) decrease, and the polymer molecular weight (M n ) increases. Thus, it can be seen that when irradiated with ultraviolet-visible light, the compounds shown in Formula (V) and Formula (VII) undergo trans-cis isomerization, increasing the steric shielding effect of the metal center and making it less likely to undergo β-H elimination, that is, reducing the chain transfer efficiency, so the activity decreases and the polymer molecular weight increases.

[0215] By comparing the data in the first row and the third row of Table 4, after being oxidized by AgBAF, in the copolymerization reaction of ethylene and polar monomer catalyzed by the compound shown in Formula (V), the polymerization activity (Act) of the polymer decreases, and the polymer molecular weight (M n ) decreases. Thus, it can be seen that the electron-withdrawing effect of the oxidized ferrocene unit is stronger, reducing the electron cloud density of the palladium metal center and making it more electrophilic. The β-H elimination is more likely to occur during the polymerization process, that is, the chain transfer rate is increased, so the activity decreases and the polymer molecular weight obtained decreases.

[0216] By comparing the data in the first row and the fourth row of Table 4, after being oxidized by AgBAF and under ultraviolet-visible light irradiation, in the copolymerization reaction of ethylene and polar monomer catalyzed by the compound shown in Formula (V), the polymerization activity (Act) of the polymer decreases, and the polymer molecular weight (M n ) decreases. Thus, it can be seen that the redox regulation plays a dominant role.

[0217] Table 5 shows the effects of different compounds coordinated with small borane Lewis acids on the copolymerization reaction of ethylene and polar monomers.

[0218]

[0219] The polymerization reaction conditions in Table 5 are as follows: Pd catalyst = 10 μmol, time = 2 h, DCM = 20 mL, ethylene pressure = 8 atm, total volume of dichloromethane and polar monomer = 20 mL, time = 2 h. Among them, the polymerization is repeated at least 2 times or more. b Activity = 10 4 g·mol -1 ·h -1 , c The molecular weight was measured by GPC using tetrahydrofuran as the solvent at 25 °C. d The insertion ratio of the polar monomer was determined by 1 1H NMR; where Pd2 represents the compound shown in Formula (VI); Pd2 + represents the compound shown in Formula (VIII).

[0220] By comparing the data in the first row and the second row of Table 5, after being oxidized by AgBAF, in the copolymerization reaction of ethylene and polar monomer catalyzed by the compound shown in Formula (VI), the polymerization activity (Act) of the polymer decreases, and the molecular weight of the polymer (M n ) decreases. It can be seen that the electron-withdrawing effect of the oxidized ferrocene unit is stronger, which reduces the electron cloud density of the palladium metal center, making it more electrophilic, and β-H elimination is more likely to occur during the polymerization process, that is, the chain transfer rate is increased, so the activity is reduced and the molecular weight of the obtained polymer is reduced.

[0221] By comparing the data in the first row and the third row of Table 5, after adding small borane, in the copolymerization reaction of ethylene and polar monomer catalyzed by the compound shown in Formula (VI), the polymerization activity (Act) of the polymer decreases, and the molecular weight of the polymer (M n ) increases slightly. From the single crystal structure, it can be seen that the distance between the palladium metal center and the cyano group is relatively close. After the small borane coordinates with the cyano unit, the steric shielding effect of the metal center will be improved, resulting in a decrease in activity and an increase in the molecular weight of the polymer.

[0222] By comparing the data in the first row and the fourth row of Table 5, after oxidation and then adding small borane, in the copolymerization reaction of ethylene and polar monomer catalyzed by the compound shown in Formula (VI), the polymerization activity (Act) of the polymer decreases, and the molecular weight of the polymer (M n ) decreases. It can be seen that redox regulation plays a dominant role.

[0223] In summary, the above palladium compound participates in the polymerization reaction for preparing polyolefin as a catalyst. Through the oxidation of the ferrocene unit in the palladium compound by AgBAF, under the irradiation of 365 nm ultraviolet visible light, the trans azobenzene unit rapidly isomerizes to the cis form, while under the irradiation of 420 nm ultraviolet visible light, the cis structure can return to the trans structure. Furthermore, the oxidation-reduction agent and light are simultaneously used to regulate the olefin polymerization process, so as to obtain polyolefins with different molecular weights and degrees of branching, thereby realizing the means of dual regulation of olefin polymerization by oxidation-reduction and light. In addition, the ferrocene unit in the above palladium compound is oxidized by AgBAF and coordinated with the cyano unit and the Lewis acid tris(pentafluorophenyl)borane. Furthermore, the oxidation-reduction agent and Lewis acid-base are simultaneously used to regulate the olefin polymerization process, so as to obtain polyolefins with different molecular weights and degrees of branching, thereby realizing the means of dual regulation of olefin polymerization by oxidation-reduction and Lewis acid-base.

[0224] The specific embodiments described above have further elaborated on the purpose, technical solutions, and beneficial effects of the present disclosure. It should be understood that the above are only specific embodiments of the present disclosure and are not used to limit the present disclosure. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present disclosure shall be included within the protection scope of the present disclosure.

Claims

1. A ligand compound with dual responsiveness, characterized in that, It has the structure shown in formula (I): Formula (I) Wherein, Ar1 is selected from substituted phenyl groups, and the substituted phenyl groups carry at least one ferrocene substituent; Ar2 is selected from substituted naphthyl groups, and the substituted naphthyl groups carry at least one phenyl azo substituent or a cyano substituent, and the phenyl azo substituent or the cyano substituent is connected to the naphthyl group via a phenyl group.

2. The ligand compound according to claim 1, characterized in that: The substituents on the substituted phenyl group further include at least one substituent selected from benzhydryl, isopropyl, methyl, tert-butyl, phenyl; and / or The substituents on the substituted naphthyl group further include at least one substituent selected from isopropyl, methyl, tert-butyl, phenyl.

3. A method for preparing the ligand compound according to claim 1, characterized in that, The method includes: React compound A with compound B to obtain compound C , and then react with compound D to obtain the ligand compound having the structure shown in formula (I); Wherein, Ar1 is selected from substituted phenyl groups, and the substituted phenyl groups carry at least one ferrocene substituent; Ar2 is selected from substituted naphthyl groups, and the substituted naphthyl groups carry at least one phenyl azo substituent or a cyano substituent, and the phenyl azo substituent or the cyano substituent is connected to the naphthyl group via a phenyl group.

4. The method according to claim 3, characterized in that: Adding compound B and an organic acid catalyst to an organic solution of compound A, reacting at a preset temperature to obtain compound C; Adding the compound C and the organic acid catalyst to an organic solution of compound D in sequence, reacting at the preset temperature to obtain a ligand compound having the structure shown in formula (I); Wherein: The solvent of the organic solution is selected from: methanol; The organic acid catalyst is selected from: any one of formic acid and acetic acid; The preset temperature is 25°C - 80°C, and the reaction time is 24h - 48h; The molar ratio of compound B to compound A is 3 - 5:1, and the molar ratio of compound D to compound C is 1 - 2:

1.

5. A palladium compound, characterized in that, It has the structure shown in formula (II): Formula (II); Wherein, Ar1 is selected from substituted phenyl groups, and the substituted phenyl groups carry at least one ferrocene substituent; Ar2 is selected from substituted naphthyl groups, and the substituted naphthyl groups carry at least one phenyl azo substituent or a cyano substituent, and the phenyl azo substituent or the cyano substituent is connected to the naphthyl group via a phenyl group.

6. A method for preparing the palladium compound according to claim 5, characterized in that, The method includes: Adding a metal palladium precursor to an organic solution of the ligand compound having the structure shown in formula (I) according to claim 1 and reacting to obtain a palladium compound having the structure shown in formula (II); Wherein: The metal palladium precursor is chloro(1,5-cyclooctadiene)methylpalladium; The molar ratio of the ligand compound having the structure shown in formula (I) to the metal palladium precursor is 1:1 - 1:1.2; The solvent in the organic solution is dichloromethane.

7. A diimine palladium catalyst with dual responsiveness, characterized in that, A palladium cationic compound having the structure shown in formula (III): Formula (III); Or an oxide having the structure shown in formula (IV): Formula (IV); Wherein, Ar1 is selected from substituted phenyl groups, and the substituted phenyl groups carry at least one ferrocene substituent; Ar2 is selected from substituted naphthyl groups, said substituted naphthyl groups bearing at least one phenylazo substituent or cyano substituent, and said phenylazo substituent or cyano substituent being attached to the naphthyl group via a phenyl group, represents a tetrakis(3,5-bis(trifluoromethyl)phenyl)borate anion.

8. A method for preparing the diimine palladium catalyst with dual responsiveness according to claim 7, characterized in that, The method includes: Reacting the palladium compound having the structure shown in formula (II) according to claim 5 and sodium tetrakis(3,5-bis(trifluoromethyl)phenyl)borate in an acetonitrile solution to obtain the palladium cationic compound having the structure shown in formula (III); or The palladium cationic compound having the structure shown in formula (III) reacts with silver tetrakis(3,5-bis(trifluoromethyl)phenyl)borate to obtain the oxide having the structure shown in formula (IV).

9. The method according to claim 8, wherein: The molar ratio of the palladium compound having the structure shown in formula (II) to sodium tetrakis(3,5-bis(trifluoromethyl)phenyl)borate is 1:1 to 1.2, and the reaction time is 10 - 12 h; The molar ratio of the palladium cationic compound having the structure shown in formula (III) to silver tetrakis(3,5-bis(trifluoromethyl)phenyl)borate is 1:1 to 1.2, and the reaction time is 1 - 2 h.

10. A method for preparing polyolefins, characterized in that, The method comprises: Under optional preset conditions, homopolymerization of an olefin is catalyzed by the dual-responsive diimine palladium catalyst according to claim 7; or Copolymerization of an olefin and a polar monomer is catalyzed by the dual-responsive diimine palladium catalyst according to claim 7; wherein, the optional preset conditions are selected from at least one of the following: Ultraviolet, visible light irradiation, using a Lewis acid additive.

11. The method according to claim 10, wherein: The Lewis acid additive is selected from tris(pentafluorophenyl)borane; The olefin is selected from: ethylene or propylene; The polar monomer is selected from any one of methyl acrylate, methyl 10-undecenoate, and norbornene; The reaction temperature is 0°C - 40°C.

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