A zinc phthalocyanine covalent polymer and its application in preparing near-infrared photocatalyst

Abstract

The present invention discloses a zinc phthalocyanine covalent polymer and its use in the preparation of near-infrared photocatalysts. Flexible ethylene glycol bridges are used within the polymer structural units to polymerize into three-dimensional spherical micron-shaped products. The near-infrared photocatalyst prepared by the present invention overcomes the difficulty of conventional NIR light-controlled RDRP polymerization in aqueous solution, addressing the shortage of NIR light-controlled RDRP polymerization methods in aqueous solution and other temperature-sensitive solvents. It has efficient singlet generation, eliminating the need for deoxygenation during the polymerization reaction and allowing for simple post-processing recovery, providing excellent economic benefits.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical synthesis, and in particular relates to a zinc phthalocyanine covalent polymer and an application thereof in the preparation of a near-infrared photocatalyst. Background Art

[0002] Polymers are high-molecular-weight compounds composed of numerous structural units linked by covalent bonds. Their molecular weights can range from thousands to millions, and they exhibit a wide variety of topological structures, including linear, branched, star-shaped, tree-like, and comb-like structures. Polymers with different topologies exhibit distinct physicochemical properties and functionalities, resulting in a wide range of applications across numerous fields. The molecular weight distribution and molecular weight of a polymer are crucial, determining its ultimate properties and applications. For example, a narrowing of the molecular weight distribution significantly improves a polymer's thermal, mechanical, flow-modifying, and crystallization properties. However, polymers formed by traditional polymerization methods suffer from broad molecular weight distributions and uncontrollable molecular weights, making it difficult to pre-design the polymer's physicochemical properties and functionality. Consequently, reversible deactivation radical polymerization (RDRP) has emerged as a promising method for synthesizing polymers with specialized structures and functionalities, finding widespread application across various disciplines.

[0003] In addition to being able to specifically design the molecular structure and topology of polymers, the RDRP method can also introduce other functional groups into polymer molecules to achieve some special applications, such as optical imaging, photodynamic therapy, photothermal conversion materials, etc. In biological applications, polymer materials are generally required to be safe and non-toxic. Through different methods, amphiphilic molecules or polymers can be formed into functional nanomicelles, which can enter the body through cellular endocytosis. Their structural design, low toxicity, and good biocompatibility have made them widely used in the biomedical field. Nanomicelles formed by nanosized (<100nm) amphiphilic block polymers have a clearly layered core-shell structure and can be used for research in the field of drug delivery. Through targeting groups or enhanced permeability retention (EPR), nanomicelles can be locally enriched in specific locations to achieve the effect of local precision treatment.

[0004] Light is the most common and abundant resource in nature, ubiquitous in our daily lives. With the advancement of science and technology, the utilization of light resources has been widely researched and applied. Due to the wave-particle duality of light, its wave and particle properties vary depending on the wavelength (or frequency) range. In the long-wavelength (low-frequency) region, light exhibits a more pronounced wave nature and lower energy; in the short-wavelength (high-frequency) region, its particle nature is more pronounced, with higher photon energy, capable of inducing numerous chemical reactions. Therefore, short-wavelength light is easily absorbed by various media in its path, resulting in a shorter propagation distance and, consequently, weaker penetration. In contrast, light in the long-wavelength region exhibits weaker tissue absorption, scattering, reflection, and autofluorescence, resulting in deeper tissue penetration. In daily life, when we hold our hands in sunlight, we can observe a red glow from our fingers due to the excellent penetrating power of NIR light. This exceptional penetrating power offers a wealth of potential applications for NIR light in fields such as biomedicine. Currently, RDRP primarily uses high-energy, low-wavelength light sources, such as ultraviolet (λ≈350nm) and blue light (λ≈460nm), as external regulators to initiate photopolymerization, which can produce unwanted side reactions. Furthermore, radiation between 400 and 700nm accounts for only 44% of total solar energy, while radiation above 700nm accounts for 52%. To fully utilize solar energy and overcome the weak penetration of high-energy, short-wavelength light sources, some RDRP photocatalysts sensitive to low-energy, long-wavelength light (λ>700nm) have been explored, but have not yet been widely used.

[0005] Currently, near-infrared photosensitizers for photocontrolled RDRPs primarily focus on porphyrins, cyanines, and phthalocyanines, with phthalocyanines being the most widely used. Phthalocyanine molecules consist of a large, cyclic, conjugated colorant system with 18 π electrons and aromatic groups. Due to strong π-π stacking interactions, phthalocyanine molecules tend to aggregate and lose their photosensitivity. Currently, this obstacle is primarily overcome by covalently attaching various substituents to the phthalocyanine benzene ring or, when the valence of the central metal is greater than 2, by modifying the axial ligands. However, these measures can also lead to photodegradation of the phthalocyanine molecules, limiting their application in certain areas. Phthalocyanine aggregation can also be disrupted by bridging metal phthalocyanine molecules into networks, such as metal-organic frameworks (MOFs), covalent organic frameworks (COFs), or covalent polymers. Covalent organic frameworks and covalent polymers formed from metal phthalocyanines typically use rigid bridges, such as 3,4,9,10-perylenetetracarboxylic dianhydride, terephthalic acid, and 1,4-benzodiboronic acid. Flexible chains for bridging are rarely reported. To date, only a few reports have used self-assembled porphyrins or water-soluble phthalocyanines to conduct near-infrared light-controlled RDRP in aqueous media. Most near-infrared light-controlled RDRP is carried out in organic solvents, which is unfavorable for further application from an economic and environmental perspective. Currently available near-infrared light-controlled aqueous RDRP systems primarily utilize homogeneous photocatalysts. For example, Boyer and colleagues used water-soluble tetrasulfonated zinc phthalocyanine as a photocatalyst to carry out aqueous reversible addition-fragmentation chain transfer (RAFT) polymerization under near-infrared light (λ = 730 nm). Due to the penetrating power of near-infrared light, polymerization can proceed through polymerization-induced self-assembly in the presence of a barrier. There are also a few reports on heterogeneous photocatalysts for RDRP in aqueous media. Recently, Hou and colleagues used nitrogen-doped fully conjugated covalent organic frameworks as heterogeneous photocatalysts to carry out aqueous RAFT polymerization under white light (λ = 420-750 nm), obtaining polymers with low dispersibility and controllable molar mass. Heterogeneous photocatalysts can be conveniently separated from the system for recycling, which makes them attractive in terms of environmental and economic benefits. Summary of the Invention

[0006] To solve the above problems, the present invention provides a three-dimensional spherical zinc phthalocyanine covalent polymer and a method for near-infrared light-controlled RAFT polymerization in water using a recyclable near-infrared photocatalyst without the need for deoxygenation.

[0007] The first object of the present invention is to provide a zinc phthalocyanine covalent polymer having the following general structural formula:

[0008]

[0009] A second object of the present invention is to provide a method for preparing the above-mentioned zinc phthalocyanine covalent polymer, comprising the following steps:

[0010] (1) reacting 4-nitrophthalonitrile with a compound represented by formula (I) in the presence of an acid-binding agent and a solvent to obtain an intermediate product represented by formula (II);

[0011] (2) reacting the intermediate product with zinc acetate in the presence of a catalyst and an alcohol solvent to obtain the zinc phthalocyanine covalent polymer;

[0012] Wherein, the structural formulas of formula (I) and formula (II) are as follows:

[0013]

[0014] Furthermore, in step (1), the molar ratio of the 4-nitrophthalonitrile, the compound represented by formula (I) and the acid binding agent is 2-3:1:3-4.

[0015] Furthermore, in step (1), the reaction temperature is 20-30° C., and the reaction time is 60-70 h.

[0016] Furthermore, in step (2), the molar ratio of the intermediate product, zinc acetate and catalyst is 1:0.3-0.5:1-1.5.

[0017] Furthermore, in step (2), the reaction temperature is 100-200° C., and the reaction time is 8-24 h.

[0018] Furthermore, the acid binding agent is potassium carbonate, and the catalyst is 1,8-diazacyclo[5.4.0]undec-7-ene.

[0019] The third object of the present invention is to provide the use of the zinc phthalocyanine covalent polymer in the preparation of near-infrared photocatalysts.

[0020] The fourth object of the present invention is to provide the use of the zinc phthalocyanine covalent polymer in the preparation of singlet oxygen.

[0021] Furthermore, the zinc phthalocyanine covalent polymer, the singlet oxygen scavenger and the solvent are mixed, and singlet oxygen is captured under near-infrared light.

[0022] A fifth object of the present invention is to provide the use of the above zinc phthalocyanine covalent polymer in the preparation of a reversible-deactivated free radical polymerization catalyst, such as as a recyclable photocatalyst in near-infrared light-controlled RAFT polymerization (reversible addition-fragmentation chain transfer polymerization).

[0023] Furthermore, the reversible-deactivated free radical polymerization reaction system includes zinc phthalocyanine covalent polymer, polymerization monomer, reducing agent, chain transfer agent and solvent.

[0024] Furthermore, the solvent is water or an aqueous liquid, including but not limited to one or more of tap water, Wahaha water, deionized water, ultrapure water, PBS buffer with a pH of 6.5 to 7.4, and Wahaha water containing any amount of organic solvent.

[0025] Furthermore, a photo-controlled RAFT polymerization reaction is carried out at 20-30° C. under irradiation with near-infrared light (wavelength range of 650 nm-810 nm) to obtain a polymer.

[0026] Furthermore, the polymerizable monomer is a (meth)acrylate monomer or a (meth)acrylamide monomer.

[0027] Furthermore, the chain transfer agent is trithiocarbonate (TTC), 2-(butylmercaptosulfonyl) propionic acid (BTPA) or 4-((((2-carboxyethyl)thio)carbonylthio)thio)-4-cyanopentanoic acid (CTCPA). The structural formula is shown below:

[0028]

[0029] Furthermore, the reducing agent is triethanolamine and / or triethylamine.

[0030] Furthermore, the product structure obtained by near-infrared light-controlled RAFT polymerization is as follows:

[0031]

[0032] Among them, Z is

[0033] R1 is

[0034] R2 is a hydrogen atom or a methyl group;

[0035] R3 is

[0036] n is an integer of 3-1000, and m is an integer of 4-20.

[0037] Furthermore, the near-infrared light can be provided by a ring-shaped LED light source, which surrounds the outside of the reaction vessel; the light source power is greater than 3.45 mW / cm 2 .

[0038] Furthermore, the wavelength of the near infrared light is preferably 730 nm, and the power range is greater than 20 mW / cm 2 .

[0039] Furthermore, the reaction is carried out in an inert protective atmosphere or in air.

[0040] Furthermore, when the air content in the reaction system is appropriate, the polymerization can be accelerated, and it is preferred to carry out the polymerization reaction in air.

[0041] Furthermore, the molar ratio of the polymerization monomer, the chain transfer agent, the reducing agent and the zinc phthalocyanine covalent polymer is 10-500:1:1-12:0.01-0.05.

[0042] Furthermore, the zinc phthalocyanine covalent polymer exists in the system as a recyclable near-infrared photocatalyst and can be recovered and reused by simple centrifugation, such as 16,000 rpm for 10 minutes.

[0043] Furthermore, in the above method, polymers with narrow molecular weight distribution of different molecular weights can be obtained at different polymerization reaction times. Preferably, the reaction time is 0.5 to 24 hours.

[0044] Beneficial effects of the present invention:

[0045] 1. The present invention synthesizes and utilizes a three-dimensional spherical zinc phthalocyanine covalent polymer capable of efficiently generating singlet oxygen. In an aqueous phase, near-infrared light irradiation causes the three-dimensional spherical zinc phthalocyanine covalent polymer to undergo an energy level transition, exciting it from the ground state to the excited singlet state, followed by a rapid internal transition to the lowest excited singlet state. Intersystem crossing transforms the lowest excited singlet state into the lowest excited triplet state. The three-dimensional spherical zinc phthalocyanine covalent polymer in the lowest excited triplet state then directly transfers energy to surrounding oxygen, generating singlet oxygen. Under reduction by a reducing agent, the singlet oxygen is converted into an oxygen radical anion, which is then converted into a peroxyhydroxyl radical through proton transfer in water, subsequently generating reactive hydrogen peroxide. Hydrogen peroxide is converted into hydroxyl radicals by the excited three-dimensional spherical zinc phthalocyanine covalent polymer, which undergoes reversible chain transfer with the chain transfer reagent, successfully synthesizing a polymer with a narrow molecular weight distribution in the aqueous phase; this overcomes the problem that traditional NIR light-controlled RDRP cannot polymerize in aqueous solution, and makes up for the shortage of near-infrared light-controlled RDRP polymerization methods in aqueous solution and isothermal solvents.

[0046] 2. The three-dimensional spherical zinc phthalocyanine covalent polymer synthesized by the present invention has a highly efficient singlet generation capability, eliminating the need for deoxygenation during the polymerization reaction, simplifying the operation process. Furthermore, the zinc phthalocyanine covalent polymer can be recycled through simple post-processing, such as centrifugation, providing excellent economic benefits by recycling expensive catalysts. Furthermore, by utilizing the advantages of low near-infrared light energy, few side reactions, and strong penetrating power, a narrow molecular weight distribution can be synthesized in a green and simple manner. Poly(meth)acrylate and poly(meth)acrylamide polymers meet the needs of green chemistry. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 This is the NMR image of intermediate 1;

[0048] Figure 2 This is the scanning electron microscope image and infrared spectrum of the three-dimensional spherical zinc phthalocyanine covalent polymer;

[0049] Figure 3 This is a graph showing the ability of three-dimensional spherical zinc phthalocyanine covalent polymers to produce singlet oxygen at different concentrations and light intensities;

[0050] Figure 4 is the polymerization kinetics diagram of poly(ethylene glycol) methyl ether acrylate monomer;

[0051] Figure 5 This is a diagram of the "light switch" polymerization kinetics of poly(ethylene glycol) methyl ether acrylate monomer;

[0052] Figure 6 It is the GPC elution curve diagram before and after polymer chain extension;

[0053] Figure 7 This is a diagram showing the catalytic effect of three-dimensional spherical zinc phthalocyanine covalent polymers recycled and reused for different times. DETAILED DESCRIPTION

[0054] The present invention will be further described below with reference to the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it. However, the embodiments are not intended to limit the present invention.

[0055] The materials involved in the present invention are as follows:

[0056] In the following examples, the monomeric raw materials used—poly(ethylene glycol) methyl ether acrylate (PEGA), N,N-dimethylacrylamide (DMA), 2-hydroxyethyl acrylate (HEA), dimethylaminoethyl methacrylate (DMAEMA), and poly(ethylene glycol) methyl ether methacrylate (PEGMA)—were passed through a neutral alumina column to remove the polymerization inhibitor before use. All other reagents were commercially available and used directly.

[0057] The testing method involved in the present invention is as follows:

[0058] 1. UV-visible spectra were obtained at room temperature using a Shimadzu UV-2600 spectrophotometer (Kyoto, Japan) with a quartz cell optical path length of 1 cm.

[0059] 2. The morphology of the samples was observed using a Hitachi SU8010 scanning electron microscope (SEM) at an operating voltage of 5 kV. The elemental content was analyzed by energy dispersive spectroscopy (EDS) point analysis at an operating voltage of 15 kV.

[0060] 3. The monomer conversion rate was measured by Bruker 300MHz nuclear magnetic resonance (NMR) test of the polymerization solution.1 The H NMR spectrum was determined using DMSO-d6 as the solvent at room temperature; the NMR spectrum of the obtained polymer was also measured using a Bruker 300 MHz NMR spectrometer using DMSO as the deuterated reagent and tetramethylsilane (TMS) as the internal standard.

[0061] 4. The number average molecular weight (M) of the obtained polymer n,GPC ) and molecular weight distribution The molecular weight was determined by TOSOH-HLC-8320 or TOSOH-HLC-8420 gel permeation chromatography (GPC) equipped with a refractive index detector, which used a TSK gel Super AWM-H column (4.6 mm ID × 15 cm × 2), which can measure the molecular weight range of 10 3 to 10×10 5 g mol -1 The test temperature was 40 °C, and DMF (containing 0.1 w% LiBr) or ultrapure water (containing 0.2 M NaCl and 3.1 mM NaN3) was used as the eluent at a flow rate of 0.60 mL min -1 Samples were injected and tested using a TOSOH autosampler. During data analysis, PS standards were used for calibration of the DMF phase and PEG standards for the aqueous phase. GPC sample preparation was as follows: a small amount of polymer sample was dissolved in an appropriate amount of DMF or ultrapure PEG. The polymer solution was then passed through a small neutral alumina column to remove insoluble impurities. Finally, the polymer solution was injected into the test sample vial using a syringe equipped with a 0.45 μm filter tip.

[0062] 5. The light intensity of the near-infrared LED light source was determined using a 0820FD18T-TS15 laser power meter purchased from Changchun New Industries Optoelectronics Technology Co., Ltd.

[0063] 6. The ambient temperature of the polymerization system was measured using an infrared thermal imager purchased from Dongguan Xintai Instrument Co., Ltd.

[0064] Example 1 Synthesis of Three-Dimensional Spherical Zinc Phthalocyanine Covalent Polymer

[0065]

[0066] The specific preparation steps are as follows:

[0067] (1) 4-nitrophthalonitrile (4.2 g, 24.3 mmol), triethylene glycol (1.5 mL, 11.3 mmol), and anhydrous K2CO3 (6.4 g, 46.3 mmol) were mixed in a 200 mL eggplant bottle, 30 mL DMF was added and magnetically stirred at room temperature for 4 hours, and then 1 g of anhydrous K2CO3 was added and reacted for another 60 hours. The reaction solution was extracted several times with water: ethyl acetate = 1:1 to remove DMF until a precipitate appeared in the organic phase, and then the organic phase was left to precipitate the product overnight. The solid was collected by filtration and dried under vacuum overnight to obtain a light yellow powder product intermediate EDP (1.5 g, yield 32.3%). The NMR spectrum is as follows Figure 1 shown.

[0068] (2) The intermediate product EDP (0.5 g, 1.3 mmol) and anhydrous zinc acetate (116.3 mg, 0.6 mmol) were added to a 100 mL eggplant flask, and then 8 mL of 1-hexanol was added and heated to 120°C under magnetic stirring. Subsequently, DBU (209.3 μL, 1.4 mmol) was added dropwise and heated to 160°C. The reaction lasted for 6 hours and was quickly precipitated with petroleum ether. The mixture was washed alternately with a large amount of water and ethanol, and then filtered. The residue was dried under vacuum overnight to obtain a dark green product, a three-dimensional spherical zinc phthalocyanine covalent polymer (0.6 g, yield 99.5%). The results are shown in FIG. Figure 2 The scanning electron microscope image is shown in Figure 2a, the energy dispersive X-ray spectrum is shown in Figure 2b, and the infrared spectrum is shown in Figure 2c. It can be seen from the figure that the three-dimensional spherical zinc phthalocyanine covalent polymer was successfully synthesized.

[0069] Example 2 Testing of Singlet Oxygen Generation Capacity of Three-Dimensional Spherical Zinc Phthalocyanine Covalent Polymers at Different Concentrations

[0070] A DMF solution of 9,10-dimethylanthracene (50 μg / mL, 242 μM) and a three-dimensional spherical zinc phthalocyanine covalent polymer (0, 50, or 100 μg / mL) was prepared under dark conditions. The solution was placed in a 1 cm × 1 cm cuvette for UV-visible measurement and a 730 nm LED ring light source (I = 66 mW / cm 2 ) was irradiated for a designed time. During the irradiation, the system was kept in the dark to avoid external interference. The absorption intensity of DMA at 380 nm was selected as a standard to detect the singlet oxygen generation ability of the three-dimensional spherical zinc phthalocyanine covalent polymer, such as Figure 3 As shown in a.

[0071] Example 3 Testing of Singlet Oxygen Generation Capacity of Three-Dimensional Spherical Zinc Phthalocyanine Covalent Polymers under Different Light Intensities

[0072] A DMF solution of 9,10-dimethylanthracene (50 μg / mL, 242 μM) and a three-dimensional spherical zinc phthalocyanine covalent polymer (100 μg / mL) was prepared under dark conditions. The solution was placed in a 1 cm × 1 cm cuvette for UV-visible testing and a 730 nm LED ring light source (I = 0.5, 10 or 66 mW / cm 2 ) was irradiated for a designed time. During the irradiation, the system was kept in the dark to avoid external interference. The absorption intensity of DMA at 380 nm was selected as a standard to detect the singlet oxygen generation ability of the three-dimensional spherical zinc phthalocyanine covalent polymer, such as Figure 3 As shown in b.

[0073] Example 4 Study on the Effects of Three-Dimensional Spherical Zinc Phthalocyanine Covalent Polymer, Reducing Agent, Chain Transfer Agent and Light on Polymerization

[0074] In this example, poly(ethylene glycol) methyl ether acrylate (PEGA) was used as a monomer, trithiocarbonate (TTC) as a chain transfer agent, triethanolamine (TEOA) as a reducing agent, and three-dimensional spherical zinc phthalocyanine covalent polymers (ZnPc-CPs) as heterogeneous photocatalysts to explore the effects of catalysts, reducing agents, chain transfer agents, and light on polymerization.

[0075] The specific operations are as follows:

[0076] In a molar ratio of R = [PEGA]0 / [TTC]0 / [TEOA]0 / [ZnPc-CPs]0 = 40:1:4:0.08, PEGA (0.341 mL, 0.8 mmol), TTC (5.64 mg, 0.02 mmol), TEOA (16 μL of triethanolamine stock solution, Wahaha water, 0.08 mmol), a three-dimensional spherical zinc phthalocyanine covalent polymer (1.6 mg, 1.7 μmol phthalocyanine unit), and 0.325 mL of water were added to a clean 2.3 mL ampoule and a clean magnetic stir bar. It is important to note that [ZnPc-CPs] here refers to the amount of phthalocyanine unit in the three-dimensional spherical zinc phthalocyanine covalent polymer. The ampoule was then sealed with plastic wrap and parafilm. The sealed ampoule was transferred to a near-infrared ring light source (λ ) equipped with a magnetic stirrer, a water-circulating cooling plate, and an electric fan. max =730nm,66mW cm -2 ) was used for photoinduced polymerization studies. After 3 hours of reaction, the ampoule was transferred to a dark place, the tube was broken, and an appropriate amount of polymer stock solution was transferred to deuterated DMSO with a pipette. 1The monomer conversion rate was calculated by HNMR test. The appropriate stock solution was pipetted into DMF containing 0.1wt% LiBr for GPC test. The mobile phase was DMF. The remaining reaction solution was filtered and dialyzed for 48 hours using a dialysis bag with a molecular weight cutoff of 3500. It was then freeze-dried until the weight remained unchanged. Table 1 shows the polymerization test results under different reaction conditions. The feed ratio in Table 1

[0077] [PEGA]0 / [TTC]0 / [TEOA]0 / [ZnPc-CPs]0. From the polymerization results in Table 1, it can be seen that the system cannot polymerize normally without the addition of three-dimensional spherical zinc phthalocyanine covalent polymer, triethanolamine reducing agent, chain transfer agent, or light. However, when the system composition is complete, a conversion rate of more than 91.9% is achieved within 3 hours.

[0078] Table 1 Test results of the effects of three-dimensional spherical zinc phthalocyanine covalent polymer, reducing agent, chain transfer agent and light on polymerization

[0079]

[0080]

[0081] Among them, number 4 is polymerization under dark conditions.

[0082] Example 5 Monomer universality study

[0083] This example uses N,N-dimethylacrylamide (DMA), 2-hydroxyethyl acrylate (HEA), dimethylaminoethyl methacrylate (DMAEMA) or poly(ethylene glycol) methyl ether methacrylate (PEGMA) as monomers, trithiocarbonate (TTC), 2-(butylmercaptothio)propionic acid (BTPA) or 4-((((2-carboxyethyl)thio)carbonylthio)thio)-4-cyanopentanoic acid (CTCPA) as chain transfer agents, triethanolamine (TEOA) as a reducing agent and three-dimensional spherical zinc phthalocyanine covalent polymers (ZnPc-CPs) as heterogeneous photocatalysts to test the system's adaptability to different types of monomers.

[0084] The specific operations are as follows:

[0085] The molar ratio R=[DMAEMA]0 / [CTCPA]0 / [TEOA]0 / [ZnPc-CPs]0=100:1:4:0.08 or [HEA]0 / [TTC]0 / [TEOA]0 / [ZnPc-CPs]0=150:1:4:0.08 or [DMA]0 / [BTPA]0 / [TEOA]0 / [ZnPc-CPs]0=150:1:4:0.08 or [PEGMA]0 / [CTCPA]0 / [TEOA]0 / [Zn Pc-CPs]0=20:1:4:0.08 for polymerization reaction, such as adding DMAEMA (0.421mL, 2.5mmol), CTCPA (7.7mg, 0.025mmol), TEOA (20μL triethanolamine storage solution, solvent is Wahaha water, 0.1mmol), three-dimensional spherical zinc phthalocyanine covalent polymer (2.0mg, 2.1μmol phthalocyanine unit) and 0.401mL water into a clean 2.3mL ampoule, and adding a clean magnetic stirrer. It is worth noting that [ZnPc-CPs] here is the amount of phthalocyanine unit in the three-dimensional spherical zinc phthalocyanine covalent polymer. Subsequently, the ampoule is sealed with plastic wrap and sealing film. The sealed ampoule is transferred to a near-infrared ring light source (λ equipped with a magnetic stirrer, a water circulation cooling plate and an electric fan). max =730nm,66mW cm -2 ) was used for photoinduced polymerization studies. After 5-10 hours of reaction, the ampoule was transferred to a dark place, the tube was broken, and an appropriate amount of polymer stock solution was transferred with a pipette into deuterated DMSO for 5-10 minutes. 1 Monomer conversion was calculated using HNMR analysis. Appropriate amounts of the stock solution were pipetted into Wahaha water for GPC analysis. The mobile phase was ultrapure water containing sodium azide and sodium chloride. The remaining reaction solution was dialyzed for 48 hours using a 3500 molecular weight cutoff dialysis bag and then freeze-dried to a constant weight. The feed ratios [M] 0 / [CTA] 0 / [TEOA] 0 / [ZnPc-CPs] 0 in Table 2 yielded polymers with ultra-narrow molecular weight distributions for all monomers.

[0086] Table 2 Test results of polymerization of various monomers

[0087]

[0088] Example 6 Kinetic Study Using PEGA as a Model Monomer

[0089] In order to study the polymerization process in detail, three-dimensional spherical zinc phthalocyanine covalent polymer was selected as the heterogeneous photocatalyst and TTC as the chain transfer agent. The aqueous phase RAFT polymerization kinetics of PEGA monomer under near-infrared light was studied with the feed ratio of [PEGA]0 / [TTC]0 / [TEOA]0 / [ZnPc-CPs]0=40:1:4:0.08.

[0090] The specific operations are as follows:

[0091] Prepare 5 clean 2.3mL ampoules, add PEGA (0.341mL, 0.8mmol), TTC (5.64mg, 0.02mmol), TEOA (16μL triethanolamine storage solution, the solvent is Wahaha water, 0.08mmol), three-dimensional spherical zinc phthalocyanine covalent polymer (1.6mg, 1.7μmol phthalocyanine unit) and 0.325mL water to each ampoule, and then add a clean magnetic stirrer. It is worth noting that [ZnPc-CPs] here is the amount of phthalocyanine unit in the three-dimensional spherical zinc phthalocyanine covalent polymer. Subsequently, seal the ampoule with plastic wrap and sealing film. Transfer the sealed ampoule to a near-infrared ring light source (λ equipped with a magnetic stirrer, a water circulation cooling plate and an electric fan). max =730nm,66mW cm -2 ) were used to study the photoinduced polymerization. One ampoule was taken out at 1, 1.5, 2, 2.5, and 3 hours, and the ampoule was transferred to a dark place. The tube was broken and the appropriate polymer stock solution was transferred to deuterated DMSO with a pipette. 1 The monomer conversion was calculated by HNMR analysis. Appropriate stock solutions were pipetted into DMF containing 0.1 wt% LiBr for GPC analysis with DMF as the mobile phase. The results are shown in Table 3.

[0092] Table 3 Test results at different polymerization times

[0093]

[0094] According to the results in Table 3, we can get Figure 4 The polymerization kinetics diagram, Figure 4 (a) shows that there is an induction period of about 50 minutes at the beginning of the polymerization, and the growth of monomer ln([M]0 / [M]) with time in the polymerization reaction shows a nearly first-order linear kinetic relationship; Figure 4 (b) shows that the molecular weight of the polymer increases linearly with the increase of conversion rate, which is consistent with the "active" characteristics of reversible-inactivation polymerization, and the molecular weight distribution of the polymer Its polymerization rate is fast. Figure 4(c) is the in situ GPC elution curve of the polymer. The reaction time corresponding to the curves from right to left in the figure increases successively, and all elution curves show a perfect normal distribution. As the polymerization time increases, the peak of the corresponding monomer gradually decreases. The GPC elution time of the obtained polymer continues to decrease, and the peak shape is very narrow, indicating that basically no dead chains are generated during the polymerization process.

[0095] Example 7 Study on the “Photo-Switch” Control of PEGA Monomer

[0096] Three-dimensional spherical zinc phthalocyanine covalent polymer was used as a heterogeneous photocatalyst, TTC as a chain transfer agent, and the feed ratio of [PEGA]0 / [TTC]0 / [TEOA]0 / [ZnPc-CPs]0=40:1:4:0.08 to study the "photoswitching" kinetics of aqueous RAFT polymerization of PEGA monomer under near-infrared light.

[0097] The specific operations are as follows:

[0098] Prepare 9 clean 2 ml ampoules, add PEGA (0.341 mL, 0.8 mmol), TTC (5.64 mg, 0.02 mmol), TEOA (16 μL triethanolamine storage solution, the solvent is Wahaha water, 0.08 mmol), three-dimensional spherical zinc phthalocyanine covalent polymer (1.6 mg, 1.7 μmol phthalocyanine unit) and 0.325 mL water to each ampoule, and then add a clean magnetic stirrer. It is worth noting that [ZnPc-CPs] here is the amount of phthalocyanine unit in the three-dimensional spherical zinc phthalocyanine covalent polymer. Subsequently, seal the ampoule with plastic wrap and sealing film. Transfer the sealed ampoule to a near-infrared ring light source (λ ) equipped with a magnetic stirrer, a water circulation cooling plate and an electric fan. max =730nm,66mW cm -2 ) were used to study photoinduced polymerization. One tube was taken out at 1 hour and 1.5 hours respectively. The light source was then turned off for 1 hour and one tube was taken out. The light source was then turned on for 0.5 hours and one tube was taken out. The light source was then turned off for 1 hour and one tube was taken out. The light source was then turned on and one tube was taken out at 0.5 hours and 1 hour respectively. After taking out the tube, it was immediately moved to a dark place and broken. The subsequent conversion rate and other characteristics were the same as in Example 6. The results are shown in FIG. Figure 5 The results show that the near-infrared light-controlled polymerization system has excellent time controllability. When the near-infrared light is irradiated, the system undergoes polymerization reaction, and when the near-infrared light is turned off, the system basically stops the polymerization reaction.

[0099] Example 8 Preparation and Chain Extension Study of Macromolecular RAFT Agents

[0100] The specific operations are as follows:

[0101] In a molar ratio of R = [PEGA]0 / [BTPA]0 / [TEOA]0 / [ZnPc-CPs]0 = 20:1:4:0.08, PEGA (0.341 mL, 0.8 mmol), BTPA (9.5 mg, 0.04 mmol), TEOA (32 μL of triethanolamine stock solution, Wahaha water, 0.16 mmol), a three-dimensional spherical zinc phthalocyanine covalent polymer (3.2 mg, 3.4 μmol phthalocyanine unit), and 0.309 mL of water were added, followed by a clean magnetic stirrer. Note that [ZnPc-CPs] here refers to the amount of phthalocyanine unit in the three-dimensional spherical zinc phthalocyanine covalent polymer. The ampoule was then sealed with plastic wrap and parafilm. The sealed ampoule was transferred to a near-infrared ring light source (λ) equipped with a magnetic stirrer, a water-circulating cooling plate, and an electric fan. max =

[0102] 730nm, 66mW cm -2 ) was used for photoinduced polymerization studies. After the reaction, the ampoule was transferred to a dark place, the tube was broken, and an appropriate amount of polymer stock solution was transferred to deuterated DMSO with a pipette. 1 Monomer conversion was calculated using HNMR analysis. An appropriate amount of the stock solution was pipetted into DMF containing 0.1 wt% LiBr for GPC analysis using DMF as the mobile phase. The remaining reaction solution was dialyzed for 48 hours using a 3500 molecular weight cutoff dialysis bag and then freeze-dried to a constant weight. The resulting product was a macromolecular RAFT agent. The polymerization results are shown in Table 4. The feed ratios in Table 4 are [PEGA] 0.0 / [BTPA] 0.0 / [TEOA] 0.0 / [ZnPc-CPs] 0.0.

[0103] Table 4 Test of macromolecular RAFT agents

[0104]

[0105] Take the macromolecular RAFT agent, triethanolamine, three-dimensional spherical zinc phthalocyanine covalent polymer and PEGA monomer and add them to a 2.3mL ampoule. Macromolecular RAFT agent (181.6mg, 18.7μmol), PEGA (318μL, 0.75mmol), TEOA (30μL triethanolamine storage solution, the solvent is Wahaha water, 0.15mmol), three-dimensional spherical zinc phthalocyanine covalent polymer (2.5mg, 2.6μmol phthalocyanine unit) and 0.282mL water are added to a clean 2.3mL ampoule. Subsequently, the ampoule is sealed with plastic wrap and sealing film. The sealed ampoule is transferred to a near-infrared ring light source (λ equipped with a magnetic stirrer, a water circulation cooling plate and an electric fan). max =730nm,66mW cm -2) was used for photoinduced polymerization studies. After the reaction, the ampoule was transferred to a dark place, the tube was broken, and an appropriate amount of polymer stock solution was transferred to deuterated DMSO with a pipette. 1 The monomer conversion was calculated by HNMR testing. The appropriate stock solution was pipetted into DMF containing 0.1 wt% LiBr for GPC testing. The mobile phase was DMF. The remaining reaction solution was dialyzed for 48 hours using a dialysis bag with a molecular weight cutoff of 3500 and then freeze-dried to a constant weight. The GPC elution curves before and after chain extension are shown in Figure 2. Figure 6 The chain extension results are shown in Table 5, and the feed ratio in Table 5 is [PEGA]0 / [macro-CTA]0 / [TEOA]0 / [ZnPc-CPs]0.

[0106] Table 5 Polymerization results after chain extension

[0107]

[0108] The results show that the molecular weight distribution is still narrow after chain extension, especially when BTPA is used as a chain transfer agent. Moreover, the GPC curves before and after chain extension shifted significantly and the peak shape hardly changed, indicating the active characteristics of the polymerization system.

[0109] Example 9 Recycling and catalytic efficiency of three-dimensional spherical zinc phthalocyanine covalent polymer

[0110] The recycling experiment of three-dimensional spherical zinc phthalocyanine covalent polymer was carried out by using three-dimensional spherical zinc phthalocyanine covalent polymer that was recycled for different times as a heterogeneous photocatalyst, PEGA as a monomer, TTC as a chain transfer reagent, and triethanolamine as a reducing agent.

[0111] The specific operations are as follows:

[0112] After the polymerization reaction is carried out using unused three-dimensional spherical zinc phthalocyanine covalent polymer, the reaction solution is diluted with water and then centrifuged to remove the supernatant. This is repeated three times to obtain a three-dimensional spherical zinc phthalocyanine covalent polymer with a cycle number of 1. Similarly, three-dimensional spherical zinc phthalocyanine covalent polymers with cycles of 0-5 are obtained respectively.

[0113] In a molar ratio of R = [PEGA]0 / [TTC]0 / [TEOA]0 / [ZnPc-CPs]0 = 20:1:4:0.08, PEGA (0.341 mL, 0.8 mmol), TTC (11.4 mg, 0.04 mmol), TEOA (32 μL of triethanolamine stock solution, 0.16 mmol in Wahaha water), a three-dimensional spherical zinc phthalocyanine covalent polymer (3.2 mg, 3.4 μmol phthalocyanine moiety) that had been recycled for different times, and 0.309 mL of water were added. A clean magnetic stirrer was then added. It is important to note that [ZnPc-CPs] here refers to the amount of phthalocyanine moiety in the three-dimensional spherical zinc phthalocyanine covalent polymer. The ampoule was then sealed with plastic wrap and parafilm. The sealed ampoule was transferred to a near-infrared ring light source (λ) equipped with a magnetic stirrer, a water-circulating cooling plate, and an electric fan. max =

[0114] 730nm, 66mW cm -2 ) was used for photoinduced polymerization studies. After the reaction, the ampoule was transferred to a dark place, the tube was broken, and an appropriate amount of polymer stock solution was transferred to deuterated DMSO with a pipette. 1 The monomer conversion was calculated by HNMR analysis. An appropriate amount of the stock solution was pipetted into DMF containing 0.1 wt% LiBr for GPC analysis. The mobile phase was DMF. The remaining reaction solution was dialyzed for 48 hours using a dialysis bag with a molecular weight cutoff of 3500 and then freeze-dried to a constant weight. The obtained product was a macromolecular RAFT agent. The polymerization results were as follows: Figure 7 shown.

[0115] The results showed that after five reuses, the three-dimensional spherical zinc phthalocyanine covalent polymer maintained its excellent catalytic efficiency with no significant performance degradation. The simple recycling method makes it have excellent economic and environmental benefits.

[0116] In the present invention, the polymerization monomers used may also be other water-soluble (meth)acrylate and (meth)acrylamide monomers other than PEGA, DMA, PEGMA, DMAEMA, and HEA, and a polymer with a narrow molecular weight distribution may be obtained by using a suitable initiator.

[0117] In summary, the present invention synthesizes a three-dimensional spherical zinc phthalocyanine covalent polymer that can efficiently generate singlet oxygen and successfully performs RAFT polymerization in an aqueous phase, thereby overcoming the problem that traditional NIR light-controlled RDRP cannot polymerize in aqueous solution. At the same time, the three-dimensional spherical zinc phthalocyanine covalent polymer maintains excellent catalytic performance as a heterogeneous catalyst while being able to be recycled and reused through a simple method, bringing about industrial application prospects. In addition, by utilizing the advantages of low energy, few side reactions and strong penetration of near-infrared light, the system is green and simple, with unparalleled environmental and economic benefits.

[0118] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A zinc phthalocyanine covalent polymer, characterized in that The zinc phthalocyanine covalent polymer has the following general structural formula: ； The preparation method of the zinc phthalocyanine covalent polymer comprises the following steps: (1) reacting 4-nitrophthalonitrile with the compound represented by formula (I) in the presence of an acid binder and a solvent to obtain an intermediate product represented by formula (II); (2) reacting the intermediate product with zinc acetate in the presence of a catalyst and an alcohol solvent to obtain the zinc phthalocyanine covalent polymer; Wherein, the structural formulas of formula (I) and formula (II) are as follows: 。 2. The zinc phthalocyanine covalent polymer according to claim 1, characterized in that: In step (1), the molar ratio of the 4-nitrophthalonitrile, the compound represented by formula (I) and the acid binding agent is 2-3:1:3-4.

3. The zinc phthalocyanine covalent polymer according to claim 1, characterized in that: In step (2), the molar ratio of the intermediate product, zinc acetate and catalyst is 1:0.3~0.5:1~1.

5.

4. Use of the zinc phthalocyanine covalent polymer according to any one of claims 1 to 3 in the preparation of near-infrared photocatalysts.

5. Use of the zinc phthalocyanine covalent polymer according to any one of claims 1 to 3 in the preparation of singlet oxygen.

6. The use according to claim 5, characterized in that: Zinc phthalocyanine covalent polymer, singlet oxygen scavenger and solvent are mixed to carry out singlet oxygen capture under near-infrared light.

7. Use of the zinc phthalocyanine covalent polymer according to any one of claims 1 to 3 in the preparation of a reversible-deactivated free radical polymerization catalyst.

8. The use according to claim 7, characterized in that: The reversible-deactivated free radical polymerization reaction system includes zinc phthalocyanine covalent polymer, polymerization monomer, reducing agent, chain transfer agent and solvent.

9. The use according to claim 8, characterized in that: The polymerizable monomer is selected from (meth)acrylate monomers and / or (meth)acrylamide monomers.

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