A living polymerized cyclic palladium catalyst, its preparation method and use

Abstract

The application discloses a kind of active polymerization cyclic palladium catalyst and its preparation method and application, its structure general formula is as follows: in the formula, R is -OCH3, n=1 or 2 or 3.The preparation method synthesis step is as follows: adding 2-bromo-5-methoxybenzoic acid and pentafluorophenol, and solid product a is obtained by reaction;Add solid product a, CuCl and reagent B, trimethylsilyl acetylene, and solid product b is obtained by reaction;Solid product b and reagent C, 4-dimethylaminopyridine are added, and solid product c is obtained by reaction;Add solid product c, fluorinated tetrabutylammonium, and solid product d is obtained by reaction;Solid product d, CuCl and reagent D are added, and active polymerization cyclic palladium catalyst e is obtained by reaction.The palladium cyclic catalyst of the application can realize a small amount of catalyst catalyzing macro-reaction, and can realize controllable active polymerization, realize the accurate synthesis of polymer, and the polymerization yield is high.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of palladium catalysts, in particular to a cyclic palladium catalyst for living polymerization and a preparation method and application thereof. BACKGROUND

[0002] Cyclic polymers are an interesting class of polymers due to the lack of chain ends. This unique cyclic topology combines steric constraints and exhibits a unique set of properties compared to linear or branched macromolecules. Cyclic polymers have smaller hydrodynamic volumes and slower degradation rates compared to linear analogues. The widespread use of cyclic structures in nature highlights the important role played by cyclic structures in conferring valuable physical properties, increasing chemical stability and self-assembly propensity. The ability to prepare cyclic polymers provides a promising new approach to modify the physical properties of polymers, especially for well-known materials prepared from traditional, cost-effective monomers with good physical properties and biodegradability. There are usually two ways to prepare cyclic polymers, ring-closing polymerization and ring-expansion polymerization. Ring-closing polymerization requires dilute concentration and intramolecular ring closure, small molecular weight, harsh conditions, not suitable for mass production, cannot be prepared in large quantities, and the structural formula is difficult to predict. Ring-expansion polymerization can prepare macro-amount of polymer with large molecular weight and small amount of catalyst. However, the existing ring-expansion polymerization cannot achieve controllable living polymerization, and the purity of the polymer is not high. SUMMARY

[0003] The present application aims to provide a cyclic palladium catalyst for living polymerization and a preparation method and application thereof, which can achieve controllable living polymerization and realize precise synthesis of polymers with high polymerization yield.

[0004] In one aspect of the present application, a cyclic palladium catalyst for living polymerization is provided. According to an embodiment of the present application, the structure general formula is as follows:

[0005]

[0006] In the formula, R is -OCH3, and n = 1 or 2 or 3.

[0007] In another aspect of the present application, a preparation method of the cyclic palladium catalyst for living polymerization is provided. According to an embodiment of the present application, the method comprises the following steps:

[0008]

[0009] (1) Add 2-bromo-5-methoxybenzoic acid and pentafluorophenol to a dry two-port bottle, and under anhydrous and anaerobic conditions, vacuumize and fill with nitrogen, add dry reagent A, add DCC, monitor by spotting plate, until the reaction is completed, and after purification, obtain solid product a;

[0010] The above reaction synthesis route is as follows:

[0011]

[0012] (2) Under the condition of no water and no oxygen, solid product a, CuCl and reagent B are added to a dry two-necked bottle, and triethylamine is used as a solvent, then trimethylsilyl acetylene is added to the bottle, the reaction mixture is stirred, and the reaction is monitored by spot plate until the reaction is completed, to obtain solid product b;

[0013] The above reaction synthesis route is as follows:

[0014]

[0015] (3) Under the protection of nitrogen, solid product b and reagent C dissolved in tetrahydrofuran are added to a dry two-necked bottle, and 4-dimethylaminopyridine is added, the reaction is monitored by spot plate until the reaction is completed, to obtain solid product c;

[0016] The above reaction synthesis route is as follows:

[0017]

[0018] (4) Under the condition of no water and no oxygen, solid product c is added to a dry two-necked bottle, and the mixture is dissolved in dry tetrahydrofuran, then the mixture is cooled to 0℃, and then tetrabutylammonium fluoride is slowly added dropwise, the reaction is monitored by spot plate, and the mixture is stirred until the reaction is completed, to obtain solid product d;

[0019] The above reaction synthesis route is as follows:

[0020]

[0021] (5) Under the condition of no water and no oxygen, solid product d, CuCl and reagent D are added to a dry two-necked bottle, and tetrahydrofuran and triethylamine are used as solvents, the reaction mixture is stirred, and the reaction is monitored by spot plate until the reaction is completed, to obtain active polymerization cyclic palladium catalyst e.

[0022] The above reaction synthesis route is as follows:

[0023]

[0024] In addition, the method for preparing an active polymerization cyclic palladium catalyst according to the above embodiment of the application can also have the following additional technical features:

[0025] In some embodiments of the application, in step (1), reagent A is one of tetrahydrofuran, chloroform and toluene; the molar mass ratio of 3-bromo-5-methoxybenzoic acid to pentafluorophenol is 1:1-2; the reaction temperature is room temperature, and the reaction time is 5 h.

[0026] In some embodiments of the present application, in the step (2), the reagent B is one of Pd(PPh3)2Cl2, Pd(PEt3)2Cl2, and Pd(PPh3)4; the molar ratio of the solid product a, CuCl, the reagent B, and trimethylsilyl acetylene is 1:0.02-0.03:0.01-0.02:1-2; the reaction temperature is 55°C, and the reaction time is 8h.

[0027] In some embodiments of the present application, in the step (3), the reagent C is one of 3-(diphenylphosphino)-1-propanol, 3-(diphenylphosphino)-1-butanol, and 3-(diphenylphosphino)-1-pentanol; the molar ratio of the solid product b, the reagent C, and 4-dimethylaminopyridine is 1:1-2:0.2-0.3; the reaction temperature is room temperature, and the reaction time is 5-6h.

[0028] In some embodiments of the present application, in the step (4), the molar ratio of the solid product c and tetrabutylammonium fluoride is 1:0.1-0.2.

[0029] In some embodiments of the present application, in the step (5), the reagent D is one of Pd(PPh3)2Cl2, Pd(PEt3)2Cl2, and Pd(PPh3)4; the molar ratio of the solid product d, CuCl, and the reagent D is 1:0.2-0.3:1-2; the reaction temperature is room temperature, and the reaction time is 1h.

[0030] In another aspect of the present application, the present application provides an application of the active polymerized cyclic palladium catalyst. According to embodiments of the present application, the active polymerized cyclic palladium catalyst can be applied to catalyze the active coordination polymerization of isonitrile derivatives.

[0031] In another aspect of the present application, the present application provides an application of the active polymerized cyclic palladium catalyst. According to embodiments of the present application, the active polymerized cyclic palladium catalyst realizes active copolymerization with isonitrile and nonpolar olefin monomers to prepare a cyclic functionalized biomaterial with a cyclic topological structure.

[0032] In addition, the application of the active polymerized cyclic palladium catalyst according to the above embodiments of the present application can have the following additional technical features:

[0033] In some embodiments of the present application, the application comprises the following specific steps: under anhydrous and anaerobic nitrogen atmosphere, a palladium catalyst, an isonitrile derivative monomer, a solvent E, a monophosphine ligand, and a nonpolar olefin monomer are sequentially added into a polymerization bottle, and the reaction is carried out under reflux at 50-60°C, and the reaction is monitored by point plate until the reaction is completed, then the reaction is terminated by adding n-hexane, and the obtained product is washed with n-hexane and vacuum dried until the mass is unchanged to obtain the cyclic functionalized biomaterial with a cyclic topological structure.

[0034] The reagent E is one of dichloromethane, ethyl acetate, and chloroform.

[0035] The isonitrile derivative monomer is

[0036] The monophosphine ligand is

[0037] The nonpolar olefin monomer is

[0038] The synthetic route for helical polymers with cyclic topological structures is as follows:

[0039]

[0040] Compared with the prior art, the beneficial effects of the present invention are:

[0041] 1) The palladium cyclic catalyst of this living polymerization can achieve large-scale reaction catalyzed by a small amount of catalyst, and can achieve controllable living polymerization, realize the precise synthesis of polymer, with high polymerization yield, and can precisely control the molecular weight and size of polymer. It can achieve precise synthesis conditions according to material requirements. The obtained active cyclic topological helical polymer has potential application value in biomaterials, pharmacokinetics, drugs, gene delivery efficiency and surface activity.

[0042] 2) This invention utilizes cyclic functionalized biomaterials obtained by catalysis of an active polymerized cyclic palladium catalyst. Due to the different filling behaviors of cyclic topological polymers, the relationship between the topological structure of the cyclic polymer and the characteristics of the resulting biomaterials allows for fine adjustment of the cyclic polymer topological structure according to application needs, thereby enabling the design of smart biomaterials for a wider range of biomedical applications. Attached Figure Description

[0043] Figure 1 This is the 1H NMR spectrum of the cyclic polyisocyanate derivative in Example 1 of this invention;

[0044] Figure 2 This is a gel permeation chromatogram of the molecular weight of the brush polymer of the cyclic polyisocyanate derivative in Example 2 of the present invention before and after ester exchange.

[0045] Figure 3 This is the 1H NMR spectrum of the cyclic polyisocyanate derivative and nonpolar olefin block copolymer in Example 3 of the present invention;

[0046] Figure 4 This is the 1H NMR spectrum of the cyclic polystyrene and isonitrile derivative block copolymer in Example 4 of the present invention. Detailed Implementation

[0047] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0048] Example 1

[0049] The preparation method of polyisocyanate derivatives is as follows:

[0050] The cyclic palladium catalyst, monophosphine ligand, and isonitrile derivative monomer were weighed in a molar ratio of 1:1:100; placed in a reaction flask, purged with nitrogen, and chloroform was added. The mixture was stirred at 55°C for 6 hours. Before heating, the solution was pale yellow; with increasing reaction time, the color gradually deepened, eventually turning dark brown, yielding the polyisocyanate derivative. The product was analyzed by 1H NMR spectroscopy (NMR spectroscopy). Figure 1 The precise synthesis of the polymer was verified, with a polymerization yield of 96%.

[0051] In this embodiment, the cyclic palladium catalyst has the following structural formula:

[0052]

[0053] The synthetic route for the polyisocyanate derivative is as follows.

[0054]

[0055] The monophosphine ligand in the formula is:

[0056]

[0057] The isonitrile derivative monomers are:

[0058]

[0059] Example 2

[0060] The preparation method of the brush polymer of cyclic isonitrile derivative is as follows: A cyclic palladium catalyst, a monophosphine ligand, and a pentafluorophenol isonitrile monomer with a molar ratio of 1:1:100 were weighed and placed in a reaction flask. Nitrogen gas was purged, chloroform was added, and the mixture was stirred at 55°C for 6 hours. Before heating, the solution was light yellow; as the reaction time increased, the solution color gradually deepened, eventually becoming dark brown, yielding the pentafluorophenol isonitrile polymer. The obtained polymer was then transesterified with hydroxymethyl 4-(ethylthio)carbonylthio)-2,2-dimethyl-4-phenylbutyric acid (PS-OH) to obtain the brush polymer of the cyclic isonitrile derivative. The brush polymer was obtained by gel permeation chromatography of different molecular weights (…). Figure 2)Verification can precisely control the polymer molecular weight M n =41.4kDa and the size of the polymer is 400nm.

[0061] In this embodiment, the cyclic palladium catalyst has the following structural formula:

[0062]

[0063] The synthetic route for the brush polymer of the above-mentioned cyclic isonitrile derivatives is as follows:

[0064]

[0065] The monophosphine ligand in the formula is:

[0066]

[0067] PS-OH is:

[0068]

[0069] The pentafluorophenol isonitrile monomer is:

[0070]

[0071] Example 3

[0072] The preparation method of isonitrile derivative monomers and nonpolar olefin block copolymerization is as follows:

[0073] A cyclic palladium catalyst, a monophosphine ligand, and an isonitrile derivative monomer were weighed in a molar ratio of 1:1:100 and placed in a reaction flask. Nitrogen gas was purged, chloroform was added, and the mixture was stirred at 55°C for 6 hours. Before heating, the solution was light yellow; as the reaction time increased, the solution color gradually deepened, eventually becoming dark brown. TLC monitoring was performed until the isonitrile derivative monomer reacted completely. Then, the nonpolar olefin monomer styrene was added, and the mixture was stirred at 55°C for 8 hours. After the reaction was complete, hexane was added to terminate the reaction. The resulting product was washed with hexane and then vacuum dried until its mass remained constant, yielding the block polymer of the isonitrile derivative and styrene. The polymer was analyzed by 1H NMR spectroscopy (NMR spectroscopy). Figure 3 )and( Figure 4 The study aims to verify the potential applications of block polymers in biomaterials, pharmacokinetics, drugs, gene delivery efficiency, and surface activity.

[0074] In this embodiment, the cyclic palladium catalyst has the following structural formula:

[0075]

[0076] The synthetic route for the block polymer of the above isonitrile derivatives with styrene is as follows:

[0077]

[0078] The monophosphine ligand in the formula is:

[0079]

[0080] The isonitrile derivative monomers are:

[0081]

[0082] Example 4

[0083] The preparation method of block copolymerization of nonpolar olefin styrene with isonitrile derivative monomers is as follows:

[0084] A cyclic palladium catalyst, a monophosphine ligand, and a nonpolar olefin monomer styrene were weighed in a molar ratio of 1:1:100 and placed in a reaction flask. Nitrogen gas was purged, chloroform was added, and the mixture was stirred at 55°C for 8 hours. Then, an isonitrile derivative monomer was added, and the mixture was stirred at 55°C for 8 hours. After the reaction was complete, hexane was added to terminate the reaction. The resulting product was washed with hexane and dried under vacuum until its mass remained constant, yielding the block polymer of styrene and the isonitrile derivative. The polymer was analyzed by 1H NMR spectroscopy (NMR spectroscopy). Figure 3 )and( Figure 4 The study aims to verify the potential applications of block polymers in biomaterials, pharmacokinetics, drugs, gene delivery efficiency, and surface activity.

[0085] In this embodiment, the cyclic palladium catalyst has the following structural formula:

[0086]

[0087] The synthetic route for the block polymer of styrene and isonitrile derivatives is as follows:

[0088]

[0089] The monophosphine ligand in the formula is:

[0090]

[0091] The isonitrile derivative monomers are:

[0092]

[0093] The above description is merely an example and illustration of the structure of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the structure of the present invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. A cyclic palladium catalyst for living polymerization, characterized in that, Its general structural formula is as follows: In the formula, R is -OCH3, and n = 1, 2, or 3.

2. A method for preparing a cyclic palladium catalyst for living polymerization according to claim 1, characterized in that, Includes the following steps: (1) Add 2-bromo-5-methoxybenzoic acid and pentafluorophenol to a dry double-necked flask. Under anhydrous and oxygen-free conditions, evacuate and purge with nitrogen. Add dry reagent A, add DCC, and monitor by TLC until the reaction is complete. After purification, obtain solid product a. (2) Under anhydrous and oxygen-free conditions, add solid product a, CuCl and reagent B to a dry double-necked flask, use triethylamine as a solvent, add trimethylsilylacetylene to the flask, stir the reaction mixture, monitor the reaction by spotting on a TLC plate until the reaction is complete, and obtain solid product b. (3) Under nitrogen protection, solid product b and reagent C dissolved in tetrahydrofuran were added to a dry double-necked flask, and 4-dimethylaminopyridine was added. The reaction was monitored by TLC until the reaction was completed, and solid product c was obtained. (4) Under anhydrous and oxygen-free conditions, add solid product c to a dry double-necked flask, dissolve it in dry tetrahydrofuran, cool the mixture to 0°C, then slowly add tetrabutylammonium fluoride, check the TLC, stir until the reaction is complete, and obtain solid product d. (5) Under anhydrous and oxygen-free conditions, solid product d, CuCl and reagent D, tetrahydrofuran and triethylamine as solvents were added to a dry double-necked flask. The reaction mixture was stirred and monitored by TLC until the reaction was completed, and the cyclic palladium catalyst e for active polymerization was obtained.

3. The method for preparing a cyclic palladium catalyst for living polymerization according to claim 2, characterized in that: In step (1), reagent A is one of tetrahydrofuran, chloroform, and toluene; The molar mass ratio of 2-bromo-5-methoxybenzoic acid to pentafluorophenol is 1:1-2; The reaction temperature was room temperature, and the reaction time was 5-6 hours.

4. The method for preparing a cyclic palladium catalyst for living polymerization according to claim 2, characterized in that: In step (2), reagent B is one of Pd(PPh3)2Cl2, Pd(PEt3)2Cl2, and Pd(PPh3)4; The molar mass ratio of solid product a, CuCl, reagent B, and trimethylsilylacetylene is 1:0.02-0.03:0.01-0.02:1-2; The reaction temperature is 55-65℃, and the reaction time is 8-10h.

5. The method for preparing a cyclic palladium catalyst for living polymerization according to claim 2, characterized in that: In step (3), reagent C is one of 3-(diphenylphosphino)-1-propanol, 3-(diphenylphosphino)-1-butanol, and 3-(diphenylphosphino)-1-pentanol; The molar mass ratio of solid product b, reagent C, and 4-dimethylaminopyridine is 1:1-2:0.2-0.3; The reaction temperature is 25℃ and the reaction time is 5-6 hours.

6. The method for preparing a cyclic palladium catalyst for living polymerization according to claim 2, characterized in that: In step (4), the molar mass ratio of solid product c to tetrabutylammonium fluoride is 1:0.1-0.

2.

7. The method for preparing a cyclic palladium catalyst for living polymerization according to claim 2, characterized in that: In step (5), reagent D is one of Pd(PPh3)2Cl2, Pd(PEt3)2Cl2, and Pd(PPh3)4; The molar mass ratio of solid product d, CuCl, and reagent D is 1:0.02-0.03:1-2; The reaction temperature is room temperature, and the reaction time is 1-2 hours.

8. The application of a cyclic palladium catalyst for living polymerization according to claim 1, characterized in that: The cyclic palladium catalyst used in the active polymerization process is copolymerized with isonitriles and nonpolar olefin monomers to prepare cyclic functionalized biomaterials with cyclic topological structures.

9. The application of the cyclic palladium catalyst for living polymerization according to claim 8, characterized in that, The specific application steps are as follows: Under an anhydrous and oxygen-free nitrogen atmosphere, palladium catalyst, isonitrile derivative monomer, solvent E, monophosphine ligand, and nonpolar olefin monomer are added sequentially to a polymerization flask. The mixture is heated to 50-60℃ and refluxed. The reaction is monitored by TLC. The reaction is terminated by adding n-hexane after the reaction is completed. The obtained product is washed with n-hexane and then vacuum dried until the mass remains unchanged to obtain the cyclic functionalized biomaterial with cyclic topology. The solvent E is one of dichloromethane, ethyl acetate, and chloroform. The isonitrile derivative monomer is The monophosphine ligand is The nonpolar olefin monomer is

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