A perylene imide-based isomerization conjugated polymer and a preparation method and application thereof

Abstract

The application belongs to the technical field of heterocyclic compound preparation, and discloses a perylene imide base isomerization conjugated polymer and a preparation method and application thereof, which comprises the following steps: uniformly mixing 3,4,9,10-perylenetetracarboxylic dianhydride, amino isomer, zinc acetate and imidazole to obtain a mixture; performing thermal polycondensation reaction on the mixture by heating, cooling after the reaction is completed, adding hydrochloric acid, stirring, filtering, washing and obtaining a precipitate; and performing freeze-drying on the precipitate to obtain the perylene imide base isomerization conjugated polymer. The isomerization bridging structure design is adopted, the charge distribution in the molecule is accurately controlled, the dissociation of excitons is effectively promoted, the separation efficiency is improved, and the isomerization bridging structure with adjustable pi stacking and electronic distribution is realized.

Description

Technical Field

[0001] This invention belongs to the field of heterocyclic compound preparation technology, and relates to a perylene imide-based isomeric conjugated polymer, its preparation method, and its application. Background Technology

[0002] Against the backdrop of exponential growth in global energy demand, photocatalytic clean energy production has become one of the most promising green technologies. Current research mainly focuses on electron reduction processes, such as photocatalytic water splitting for hydrogen generation or carbon dioxide reduction, which have made significant progress in recent years. However, a complete redox process necessarily requires an oxidation reaction. The four-electron pathway and high energy barrier (+1.23 eV relative to the normal hydrogen electrode) make the oxygen evolution reaction the rate-determining step in these processes. Currently, perylene imide-based linear conjugated polymers have attracted considerable attention for oxygen evolution reactions due to their advantages: low cost, tunable photo / electric properties, strong light absorption, and a deep valence band with strong oxidation capabilities. However, like other organic semiconductor polymers, these perylene imide-based linear conjugated polymers typically exhibit limited photocatalytic performance due to significant Coulomb-mediated Frank excitons. Furthermore, key steps in the process from photoexcitation to free charge carriers include exciton dissociation and charge transfer. Methods such as modifying bridging bonds to achieve electron redistribution or improving crystallinity through molten salt synthesis are typical strategies for improving the photocatalytic oxygen evolution performance of perylene imide-based linear conjugated polymers, fundamentally accelerating exciton dynamics. However, for perylene imide-based linear conjugated polymers, strategies for precisely regulating electron distribution and adjusting π-stacking to promote simultaneous and synergistic modification of exciton dissociation and charge transfer remain rare. Moreover, the design of active sites and the underlying regulatory mechanisms have not been fully explored.

[0003] Isomers are compounds with the same molecular formula but different spatial arrangements; this structural diversity endows them with a wealth of unique physical and chemical properties. Isomerization strategies have proven effective in modulating charge distribution and have shown significant practicality in covalent organic framework materials. However, reports on the isomerization of perylene imide for oxygen electrode reactions are extremely rare, and there is also a lack of research on linear conjugated polymers based on perylene imide, resulting in a lack of reasonable theoretical design principles and guidelines. Summary of the Invention

[0004] The purpose of this invention is to provide a perylene imide-based isomeric conjugated polymer, its preparation method, and its application, thereby solving the problem that the photocatalytic performance of existing perylene imide-based linear conjugated polymers is limited by exciton dissociation and charge transfer efficiency.

[0005] To achieve the above objectives, the present invention employs the following technical solution: A method for preparing a perylene imide-based isomeric conjugated polymer, comprising: 3,4,9,10-perylenetetracarboxylic dianhydride, amino isomer, zinc acetate, and imidazole were mixed thoroughly to obtain a mixture; The mixture was heated to carry out a thermal polycondensation reaction. After the reaction was completed, it was cooled and hydrochloric acid was added. The mixture was stirred, filtered, washed, and a precipitate was obtained. The precipitate was freeze-dried to obtain a perylene imide-based isomeric conjugated polymer.

[0006] Furthermore, the molar ratio of 3,4,9,10-perylenetetracarboxylic dianhydride, amino isomer, zinc acetate, and imidazole is 1:1:1:(20~50).

[0007] Furthermore, the structural formula of the amino isomer is: H2N-(CH2) n -(CH2) m -NH2, where - represents a single or double bond.

[0008] Furthermore, the heating temperature of the mixture is 120~160℃, and the heating time is 4h; The cooling temperature is room temperature.

[0009] Furthermore, the molar concentration of hydrochloric acid is 1~4 mol / L, and the mass of hydrochloric acid is 50%~100% of the mass of the mixture.

[0010] Furthermore, the stirring speed is 400~600 r / min, and the stirring time is 8~12 h.

[0011] Furthermore, the washing process includes: The filtered precipitate was washed three times with distilled water, then washed with dimethyl sulfoxide until the color of the filtrate decreased to the preset standard. Finally, it was washed three times with distilled water to remove residual dimethyl sulfoxide.

[0012] Furthermore, the conditions for freeze-drying the precipitate were: freezing in a cold trap at -50℃ for 2 hours, followed by vacuum drying for 24 hours at a vacuum level of 10 Pa.

[0013] A perylene imide-based isomeric conjugated polymer prepared by the aforementioned method has an optical absorption edge of 600-800 nm and a carrier mobility of 2-8 cm⁻¹. 2 ·V -1 ·S -1 .

[0014] The application of the perylene imide-based isomeric conjugated polymer in photocatalytic water splitting.

[0015] Compared with the prior art, the present invention has the following beneficial effects: This invention provides a method for preparing perylene imide-based isomeric conjugated polymers. The method employs a one-step thermopolymerization reaction, using 3,4,9,10-perylenetetracarboxylic dianhydride as the core raw material, which reacts directly with the amino isomer under the catalysis of zinc acetate and imidazole, eliminating the need for complex stepwise synthesis or harsh reaction environments. By introducing amide bonds into the molecular backbone through a simple thermopolymerization reaction, compared to the single-imide bond structure of traditional perylene imide materials, the hydrophilic carbonyl group (C=O) in the amide bond significantly improves interfacial compatibility and hydrophilicity. This overcomes the bottlenecks of traditional perylene imide polymers, such as easy aggregation and poor aqueous dispersibility. Subsequent post-processing steps, including hydrochloric acid filtration, washing, and freeze-drying, are standardized, highly controllable, and effectively ensure the feasibility and reproducibility of the synthetic route. This invention utilizes an isomerization bridging structure design; the isomerization strategy can precisely control the charge distribution within the molecule. By introducing electron-rich olefin bonds, charge polarization between the perylene imide perylene core and the bridging bonds is promoted, and a strong built-in electric field is established, effectively facilitating exciton dissociation. The fixed bond angle and steric hindrance of the isomerized bridging bonds further enhance the π-stacking between perylene imide molecules, promoting a closer arrangement of the perylene imide perylene core, thereby promoting the formation of delocalized channels for fast excitons, enhancing exciton dynamics, extending exciton lifetime, and resulting in lower exciton binding energy. This accelerates the generation of free charge carriers and improves separation efficiency, achieving an isomerized bridging structure with tunable π-stacking and electron distribution. This invention enables the efficient preparation of a series of perylene imide-based polymers, significantly reducing R&D and production costs, and providing a technological foundation for large-scale industrial production.

[0016] Furthermore, the molar ratio range of 3,4,9,10-perylenetetracarboxylic dianhydride, amino isomer, zinc acetate, and imidazole is clearly given as 1:1:1:20~50. This helps to optimize the ratio of reactants, enabling the reaction to proceed more fully and efficiently, improving the yield and quality of the target product, peryleneimide-based isomeric conjugated polymer, and avoiding problems such as incomplete reaction or excessive byproducts caused by improper reactant ratios.

[0017] Furthermore, the structural formula of the amino isomer is specified as H2N-(CH2). n -(CH2) m -NH2, where - represents a single or double bond. Precisely defining the structure of the amino isomer ensures the accuracy and consistency of the reaction raw materials, which is beneficial for guaranteeing that the final synthesized perylene imide-based isomeric conjugated polymer has the expected structure and properties, providing a foundation for obtaining polymers with specific functions.

[0018] Furthermore, the heating temperature of the mixture was determined to be 120~160℃, the heating time to be 4h, and the cooling temperature to be room temperature. This allows the thermal polycondensation reaction to proceed under suitable conditions, promoting the smooth progress of the reaction, improving the selectivity of the reaction and the purity of the product; room temperature cooling simplifies the operation and avoids problems such as product structural changes that may occur due to rapid cooling, ensuring the stability of product performance.

[0019] Furthermore, it is specified that the molar concentration of hydrochloric acid is 1~4 mol / L, and its mass is 50%~100% of the mass of the mixture. This can effectively adjust the pH of the reaction system, promote the precipitation and separation of reaction products, improve the precipitation effect, and thus obtain the target product more efficiently. At the same time, it also helps to remove impurities that may exist in the reaction system and improve the purity of the product.

[0020] Furthermore, the stirring speed is specified to be 400~600 r / min, and the stirring time is specified to be 8~12 h. This ensures that the substances in the reaction system are fully mixed, guaranteeing a uniform reaction and improving reaction efficiency. It also helps the hydrochloric acid to fully contact the reaction products, promoting the precipitation process, making the precipitation more complete, and improving the product recovery rate.

[0021] Furthermore, the multi-step washing method can effectively remove various impurities adsorbed on the surface and inside of the precipitate, such as unreacted raw materials, by-products, and solvents, significantly improving the purity of the product and meeting the demand for high-purity polymers.

[0022] Furthermore, the freeze-drying conditions for the precipitate were clarified as follows: freezing in a -50℃ cold trap for 2 hours, followed by vacuum drying for 24 hours at a vacuum level of 10 Pa. This method avoids structural changes or agglomeration of the product during the drying process, maintaining its good properties and morphology. Simultaneously, drying at low temperatures effectively prevents the product from decomposing or deteriorating due to high temperatures, ensuring that the final perylene imide-based isomeric conjugated polymer has high quality and stability.

[0023] This invention also provides a perylene imide-based isomeric conjugated polymer. By using amino isomers, the double bond configuration and saturation level of the polymer backbone can be precisely controlled. The cis-double bond backbone exhibits steric hindrance, enhancing intermolecular π-π interactions and improving charge transport performance and crystallinity; the trans-double bond backbone is more planar, exhibiting higher crystallinity and improving stability and processability; the saturated alkyl chain eliminates double bond conjugation, resulting in a wide optical absorption range and mechanical flexibility, enabling directional design and optimization of optoelectronic and mechanical properties. The perylene imide fused ring unit endows the material with strong visible / near-infrared absorption and high electron mobility, and isomer selection can improve the polymer's solubility in organic solvents. This invention achieves the structurally controllable synthesis of peryleneimide-based conjugated polymers through precise design of amino isomers. The highly crystalline linear conjugated structure, combined with the stable linkage of amide bonds and the performance regulation of isomerization bridging bonds, exhibits excellent chemical stability, photothermal stability, and photoelectric response performance, with an absorption edge of 600–800 nm and a carrier mobility of 2–8 cm⁻¹. 2 ·V -1 ·S -1 Meanwhile, perylene imide itself exhibits high chemical stability, and the differentiated design of the main chain double bonds / saturated chains can further optimize thermal stability and weather resistance, extending the device's lifespan. Compared to existing non-isomerized perylene imide polymers, the product of this invention achieves significant improvements in core optoelectronic properties such as exciton dissociation efficiency and charge carrier generation rate, providing a novel structural paradigm and preparation route for the development of high-performance organic optoelectronic materials and photocatalytic materials.

[0024] This invention also provides an application of perylene imide-based isomeric conjugated polymers in photocatalytic water splitting. Through the thermal condensation reaction of 3,4,9,10-perylenetetracarboxylic dianhydride with amino isomers, perylene imide-based isomeric conjugated polymers with cis double bonds, trans double bonds, or saturated alkyl chains are prepared and applied to the field of photocatalytic water splitting. The perylene imide fused-ring structure itself possesses extremely high chemical, thermal, and photochemical stability, and is not easily decomposed under the strong oxidizing / reducing environment of photocatalytic reactions, maintaining catalytic activity for a long time and solving the problem of easy photodegradation of organic photocatalysts. The cis / trans double bonds retain the conjugation of the main chain, improving the generation efficiency of photogenerated carriers; the trans double bonds have better planarity and stronger crystallinity, which is beneficial for the rapid separation and transport of photogenerated electrons and holes, and inhibits carrier recombination; the steric hindrance of the cis double bonds can enhance intermolecular π-stacking, reduce the π-stacking distance, and generate more high-energy excitons to participate in the reaction; the saturated alkyl chains can moderately disrupt conjugation, adjust the band structure, and increase the exposure of catalytically active sites. The conjugated backbone and the electron acceptor properties of the perylene imide unit effectively separate photogenerated electrons and holes. Electrons can rapidly migrate along the perylene imide conjugated backbone to the catalytic site for electron sacrificial reactions; holes participate in water oxidation, avoiding carrier recombination and improving quantum efficiency. Simultaneously, the difference in intermolecular forces brought about by isomerization can further optimize heterojunction / interface effects and enhance charge separation. This invention, through the precise design of the heteroconjugated structure, achieves targeted regulation of the photocatalytic performance of perylene imide-based polymers. While maintaining the excellent stability of perylene imide, it maximizes visible light absorption, carrier separation, and catalytic activity, providing a new technical pathway for efficient, stable, and low-cost organic photocatalytic water splitting. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of the synthesis route of the perylene imide-based isomeric conjugated polymers in Examples 1-3 of the present invention.

[0027] Figure 2 The X-ray diffraction patterns are those of the perylene imide-based isomeric conjugated polymers prepared in Examples 1-3 of this invention.

[0028] Figure 3The images shown are scanning electron microscope (SEM) images of the perylene imide-based isomeric conjugated polymers prepared in Examples 1-3 of the present invention, wherein a) is the SEM image of the perylene imide-based isomeric conjugated polymer prepared in Example 1, b) is the SEM image of the perylene imide-based isomeric conjugated polymer prepared in Example 2, and c) is the SEM image of the perylene imide-based isomeric conjugated polymer prepared in Example 3.

[0029] Figure 4 The figures show a comparison of the photocatalytic water splitting performance of Examples 8-10 of the present invention. Detailed Implementation

[0030] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used in the specification and claims are explained and defined in general below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0031] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0032] In this document, all features defined by numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0033] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0034] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0035] The following examples use instruments and equipment conventional in the art. Experimental methods in the following examples, unless otherwise specified, are generally performed under standard conditions or as recommended by the manufacturer. All raw materials used in the following examples are conventional commercially available products with specifications in the art, unless otherwise stated.

[0036] The present invention will now be described in further detail with reference to the accompanying drawings: This invention provides a method for preparing a perylene imide-based isomeric conjugated polymer, specifically comprising the following steps: Step 1: In a flask, mix 3,4,9,10-perylenetetracarboxylic dianhydride, amino isomer, zinc acetate, and imidazole thoroughly to obtain a mixture.

[0037] Step 2: Heat the mixture to 120~160℃ and stir for 4 hours to carry out the thermal polycondensation reaction. After the reaction is complete, cool the mixture to room temperature and add hydrochloric acid. After stirring, filter the solution, wash the precipitate three times with distilled water, then wash the precipitate with dimethyl sulfoxide until the color of the filtrate decreases to the preset standard, and finally wash the precipitate three times with distilled water to remove residual dimethyl sulfoxide.

[0038] Step 3: Freeze-dry the washed precipitate for 24 hours to obtain perylene imide-based isomeric conjugated polymer.

[0039] Preferably, the structural formula of the amino isomer is: H2N-(CH2) n -(CH2) m -NH2, where - represents a single or double bond, and when it is a double bond, the amino isomer has cis-trans isomers.

[0040] Preferably, the molar ratio of 3,4,9,10-perylenetetracarboxylic dianhydride, amino isomer, zinc acetate, and imidazole is 1:1:1:20~50.

[0041] Preferably, the molar concentration of hydrochloric acid is 1~4 mol / L, and the mass of hydrochloric acid is 50%~100% of the mass of the mixture.

[0042] Preferably, the stirring speed is 400~600 r / min and the stirring time is 8~12 h.

[0043] Preferably, the filtrate after washing the precipitate with dimethyl sulfoxide is colorless as a preset standard.

[0044] Preferably, the conditions for freeze-drying the precipitate are: freezing in a cold trap at -50°C for 2 hours, followed by vacuum drying for 24 hours at a vacuum degree of 10 Pa.

[0045] This invention also provides a perylene imide-based isomeric conjugated polymer with an absorption edge of 600-800 nm and a carrier mobility of 2-8 cm⁻¹. 2 ·V -1 ·S -1 .

[0046] The present invention also provides an application of perylene imide-based isomeric conjugated polymer in photocatalytic water splitting. The perylene imide-based isomeric conjugated polymer prepared above is used as a photocatalyst, which can promote water splitting to produce oxygen under sunlight irradiation.

[0047] The technical solution of the present invention will be further described in detail below through specific embodiments: such as Figure 1 The diagram shown illustrates the synthetic pathways of the perylene imide-based isomeric conjugated polymers in Examples 1-3 of this invention. Figure 1 The synthesis paths within the three boxes correspond to Examples 1 to 3 from top to bottom.

[0048] Example 1: In a flask, 2 mmol of 3,4,9,10-perylenetetracarboxylic dianhydride, 2 mmol of maleic diamine, 2 mmol of zinc acetate, and 7.8 g of imidazole were mixed thoroughly. The mixture was then heated to 140 °C and stirred at 500 rpm for 4 h. After the reaction was complete, the mixture was cooled to room temperature and 250 mL of 1 mol / L hydrochloric acid was added. After stirring for another 10 h, the solution was filtered, and the precipitate was washed three times with distilled water. The precipitate was then washed with dimethyl sulfoxide until the filtrate was almost colorless. Finally, the precipitate was washed three times with distilled water to remove residual dimethyl sulfoxide, frozen in a -50 °C cold trap for 2 h, and vacuum dried at 10 Pa for 24 h to obtain the perylene imide-based isomeric conjugated polymer (MA-PDI). The perylene imide-based isomeric conjugated polymer prepared in this example has an optical absorption edge of 688 nm and a carrier mobility of 5.1 cm⁻¹. 2 ·V -1 ·S -1 .

[0049] Example 2: In a flask, 2 mmol of 3,4,9,10-perylenetetracarboxylic dianhydride, 2 mmol of diamine fumarate, 2 mmol of zinc acetate, and 7.8 g of imidazole were mixed thoroughly. The mixture was then heated to 140 °C and stirred at 500 rpm for 4 h. After the reaction was complete, the mixture was cooled to room temperature and 250 mL of 1 mol / L hydrochloric acid was added. After stirring for another 10 h, the solution was filtered, and the precipitate was washed three times with distilled water. The precipitate was then washed with dimethyl sulfoxide until the filtrate was almost colorless. Finally, the precipitate was washed three times with distilled water to remove residual dimethyl sulfoxide, frozen in a -50 °C cold trap for 2 h, and vacuum dried at 10 Pa for 24 h to obtain a perylene-imide-based isomeric conjugated polymer (FU-PDI). The perylene-imide-based isomeric conjugated polymer prepared in this example has an optical absorption edge of 697 nm and a carrier mobility of 4.1 cm⁻¹. 2 ·V -1 ·S -1 .

[0050] Example 3: In a flask, 2 mmol of 3,4,9,10-perylenetetracarboxylic dianhydride, 2 mmol of diamine succinate, 2 mmol of zinc acetate, and 7.8 g of imidazole were mixed thoroughly. The mixture was then heated to 140 °C and stirred at 500 rpm for 4 h. After the reaction was complete, the mixture was cooled to room temperature and 250 mL of 1 mol / L hydrochloric acid was added. After stirring for another 10 h, the solution was filtered, and the precipitate was washed three times with distilled water. The precipitate was then washed with dimethyl sulfoxide until the filtrate was almost colorless. Finally, the precipitate was washed three times with distilled water to remove residual dimethyl sulfoxide, frozen in a -50 °C cold trap for 2 h, and vacuum dried at 10 Pa for 24 h to obtain a perylene-imide-based isomeric conjugated polymer (SU-PDI). The perylene-imide-based isomeric conjugated polymer prepared in this example has an optical absorption edge of 685 nm and a carrier mobility of 3.7 cm⁻¹. 2 ·V -1 ·S -1 .

[0051] Example 4: In a flask, 2 mmol of 3,4,9,10-perylenetetracarboxylic dianhydride, 2 mmol of 1,3-cyclohexanediamine, 2 mmol of zinc acetate, and 7.8 g of imidazole were mixed thoroughly. The mixture was then heated to 120 °C and stirred at 500 rpm for 4 h. After the reaction was complete, the mixture was cooled to room temperature and 250 mL of 1 mol / L hydrochloric acid was added. After stirring for another 8 h, the solution was filtered, and the precipitate was washed three times with distilled water. The precipitate was then washed with dimethyl sulfoxide until the filtrate was almost colorless. Finally, the precipitate was washed three times with distilled water to remove residual dimethyl sulfoxide, frozen in a -50 °C cold trap for 2 h, and vacuum dried at 10 Pa for 24 h to obtain a peryleneimide-based isomeric conjugated polymer.

[0052] Example 5: In a flask, 2 mmol of 3,4,9,10-perylenetetracarboxylic dianhydride, 2 mmol of 1,4-cyclohexanediamine, 2 mmol of zinc acetate, and 3.12 g of imidazole were mixed thoroughly. The mixture was then heated to 130 °C and stirred at 400 rpm for 4 h. After the reaction was complete, the mixture was cooled to room temperature and 85 mL of 3 mol / L hydrochloric acid was added. After stirring for another 10 h, the solution was filtered, and the precipitate was washed three times with distilled water. The precipitate was then washed with dimethyl sulfoxide until the filtrate was almost colorless. Finally, the precipitate was washed three times with distilled water to remove residual dimethyl sulfoxide, frozen in a -50 °C cold trap for 2 h, and vacuum dried at 10 Pa for 24 h to obtain a peryleneimide-based isomeric conjugated polymer.

[0053] Example 6: In a flask, 2 mmol of 3,4,9,10-perylenetetracarboxylic dianhydride, 2 mmol of 1,2-diphenylethylenediamine (CAS 951-87-1), 2 mmol of zinc acetate, and 6.24 g of imidazole were mixed thoroughly. The mixture was then heated to 150 °C and stirred at 600 rpm for 4 h. After the reaction was complete, the mixture was cooled to room temperature and 62.5 mL of 4 mol / L hydrochloric acid was added. After stirring for another 8 h, the solution was filtered, and the precipitate was washed three times with distilled water. The precipitate was then washed with dimethyl sulfoxide until the filtrate was almost colorless. Finally, the precipitate was washed three times with distilled water to remove residual dimethyl sulfoxide, frozen in a -50 °C cold trap for 2 h, and vacuum dried at 10 Pa for 24 h to obtain a peryleneimide-based isomeric conjugated polymer.

[0054] Example 7: In a flask, 2 mmol of 3,4,9,10-perylenetetracarboxylic dianhydride, 2 mmol of 1,2-diphenylethylenediamine (CAS 16635-95-3), 2 mmol of zinc acetate, and 4.68 g of imidazole were mixed thoroughly. The mixture was then heated to 160 °C and stirred at 500 rpm for 4 h. After the reaction was complete, the mixture was cooled to room temperature and 125 mL of 2 mol / L hydrochloric acid was added. After stirring for another 9 h, the solution was filtered, and the precipitate was washed three times with distilled water. The precipitate was then washed with dimethyl sulfoxide until the filtrate was almost colorless. Finally, the precipitate was washed three times with distilled water to remove residual dimethyl sulfoxide, frozen in a -50 °C cold trap for 2 h, and vacuum dried at 10 Pa for 24 h to obtain a peryleneimide-based isomeric conjugated polymer.

[0055] Example 8: 0.01 g of the perylene imide-based isomeric conjugated polymer prepared in Example 1 was added to the reaction vessel as a photocatalyst, 2 wt% Co(OH)2 as a cocatalyst, and 0.10 g La2O3 as a solid base to balance the pH change during the reaction. Then, 50 mL of 0.2 mol / L AgNO3 solution was added. The added AgNO3 acted as a sacrificial agent, and the pH of the reaction system was 7. Before irradiation, the reaction mixture was sonicated for 10 min and then added to a 100 mL reactor. Argon gas was introduced into the reactor and maintained for 15 min to purge air. The reaction was stirred with a magnetic stirrer and maintained at a constant 35°C with circulating cooling water. Simulated sunlight (AM 1.5G 100 mW / cm²) was used. 2 Under irradiation, the oxygen production capacity is 2119 μmol·g. -1 ·h -1 .

[0056] Example 9: 0.01 g of the perylene imide-based isomeric conjugated polymer prepared in Example 2 was added to the reaction vessel as a photocatalyst, 2 wt% Co(OH)2 as a cocatalyst, and 0.10 g La2O3 as a solid base to balance the pH change during the reaction. Then, 50 mL of 0.2 mol / L AgNO3 solution was added. The added AgNO3 acted as a sacrificial agent, and the pH of the reaction system was 7. Before irradiation, the reaction mixture was sonicated for 10 min and then added to a 100 mL reactor. Argon gas was introduced into the reactor and maintained for 15 min to purge air. The reaction was stirred with a magnetic stirrer and maintained at a constant 35°C with circulating cooling water. Simulated sunlight (AM 1.5G 100 mW / cm²) was used. 2 Under irradiation, the oxygen production capacity is 1012 μmol·g. -1 ·h -1 .

[0057] Example 10: 0.01 g of the perylene imide-based isomeric conjugated polymer prepared in Example 3 was added to the reaction vessel as a photocatalyst, 2 wt% Co(OH)2 as a cocatalyst, and 0.10 g La2O3 as a solid base to balance the pH change during the reaction. Then, 50 mL of 0.2 mol / L AgNO3 solution was added. The added AgNO3 acted as a sacrificial agent, and the pH of the reaction system was 7. Before irradiation, the reaction mixture was sonicated for 10 min and then added to a 100 mL reactor. Argon gas was introduced into the reactor and maintained for 15 min to purge air. The reaction was stirred with a magnetic stirrer and maintained at a constant 35°C with circulating cooling water. Simulated sunlight (AM 1.5G 100 mW / cm²) was used. 2 Under irradiation, the oxygen production capacity is 680 μmol·g. -1 ·h -1 .

[0058] The performance of the perylene imide-based isomeric conjugated polymers prepared in Examples 1-3 of this invention was tested, and the X-ray diffraction patterns are shown below. Figure 2 As shown in the figure, the MA-PDI, FU-PDI, and SU-PDI prepared in Examples 1-3 all exhibit good crystallinity, with the peak near 27.2° representing the π-packing strength and π-packing spacing. Scanning electron microscopy images are shown below. Figure 3 As shown, the perylene imide-based isomeric conjugated polymers prepared in Examples 1-3 all have good short rod-like morphology, with a length of about 500-1000 nm.

[0059] The photocatalytic water splitting performance of Examples 8-10 of the present invention was analyzed, such as... Figure 4 As shown, Figure 4 The graph shows the oxygen production over time for Examples 8, 9, and 10 under simulated sunlight irradiation. From... Figure 4 As can be seen, the oxygen production of Examples 8-10 all increased continuously with the increase of illumination time, demonstrating good photocatalytic oxygen evolution performance. Among them, in Example 8, the MA-PDI prepared using Example 1 had the fastest oxygen production rate and the highest final oxygen production; in Example 9, the FU-PDI prepared using Example 2 was the second fastest; in Example 10, the SU-PDI prepared using Example 3 had a relatively slow oxygen production rate, but the oxygen production still increased steadily with the extension of time. Figure 4 The result is consistent with the oxygen production performance value of 2119 μmol·g given in Example 8. -1 ·h -1 The oxygen production performance value given in Example 9 is 1012 μmol·g. -1 ·h -1 And the oxygen production performance value of 680 μmol·g given in Example 10 -1 ·h -1 Correspondingly, this further confirms the highly efficient photocatalytic activity of the perylene imide-based isomeric conjugated polymer prepared in this invention.

[0060] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a perylene imide-based isomeric conjugated polymer, characterized in that, include: 3,4,9,10-perylenetetracarboxylic dianhydride, amino isomer, zinc acetate, and imidazole were mixed thoroughly to obtain a mixture. The mixture was heated to carry out a thermal polycondensation reaction. After the reaction was completed, it was cooled and hydrochloric acid was added. The mixture was stirred, filtered, and washed to obtain a precipitate. The precipitate was freeze-dried to obtain a perylene imide-based isomeric conjugated polymer.

2. The method for preparing the perylene imide-based isomeric conjugated polymer according to claim 1, characterized in that, The molar ratio of 3,4,9,10-perylenetetracarboxylic dianhydride, amino isomer, zinc acetate and imidazole is 1:1:1:(20~50).

3. The method for preparing the perylene imide-based isomeric conjugated polymer according to claim 1, characterized in that, The structural formula of the amino isomer is: H2N-(CH2) n -(CH2) m -NH2, where - represents a single or double bond.

4. The method for preparing the perylene imide-based isomeric conjugated polymer according to claim 1, characterized in that, The mixture is heated at 120~160℃ for 4 hours. The cooling temperature is room temperature.

5. The method for preparing the perylene imide-based isomeric conjugated polymer according to claim 1, characterized in that, The molar concentration of hydrochloric acid is 1~4 mol / L, and the mass of hydrochloric acid is 50%~100% of the mass of the mixture.

6. The method for preparing the perylene imide-based isomeric conjugated polymer according to claim 1, characterized in that, The stirring speed is 400~600 r / min, and the stirring time is 8~12 h.

7. The method for preparing the perylene imide-based isomeric conjugated polymer according to claim 1, characterized in that, The washing process includes: The filtered precipitate was washed three times with distilled water, then washed with dimethyl sulfoxide until the color of the filtrate decreased to the preset standard. Finally, it was washed three times with distilled water to remove residual dimethyl sulfoxide.

8. The method for preparing the perylene imide-based isomeric conjugated polymer according to claim 1, characterized in that, The conditions for freeze-drying the precipitate were: freezing in a cold trap at -50℃ for 2 hours, followed by vacuum drying for 24 hours at a vacuum level of 10 Pa.

9. A perylene imide-based isomeric conjugated polymer prepared by the method according to any one of claims 1 to 8, characterized in that, The light absorption edge of the perylene imide-based isomeric conjugated polymer is 600–800 nm, and the carrier mobility is 2–8 cm⁻¹. 2 ·V -1 ·S -1 .

10. The application of the perylene imide-based isomeric conjugated polymer according to claim 9 in photocatalytic water splitting.

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