Solution-processable two-dimensional halogen bond organic framework as well as preparation method and application thereof

Abstract

The invention discloses a solution-processable two-dimensional halogen bond organic framework as well as a preparation method and application thereof, and belongs to the technical field of organic high-molecular compounds. The method has the advantages of high synthesis efficiency and reduced production cost. The solubility of the two-dimensional halogen bond organic framework is remarkably enhanced by introducing a long-chain alkyl side chain and optimizing solvent selection, so that the two-dimensional halogen bond organic framework can keep good dispersity in various solvents; through a cross-linking strategy and introduction of functional groups, the structural stability of XOFs in a solution environment is improved, and the long-term reliability and performance consistency of the material are improved; a specific functional group is introduced into the framework, so that the two-dimensional halogen bond organic framework has multiple functions. The prepared two-dimensional halogen bond organic framework has the advantages of high solubility, strong structural stability and multi-functionalization characteristic, and has wide prospects in the fields of electronics and sensors.

Description

Technical Field

[0001] The invention relates to the technical field of organic polymer compounds, and in particular to a solution-processable two-dimensional halogen bond organic framework and a preparation method and application thereof. Background Art

[0002] Organic framework materials are an emerging class of functional materials, mainly composed of metal organic frameworks (MOFs) and covalent organic frameworks (COFs), and have attracted widespread attention due to their excellent performance. These materials have high crystallinity, wide surface area and multifunctionality, which makes them show good application prospects in many fields such as energy storage, separation, electronic devices and medical applications. However, the application of these framework materials is limited by their solubility, especially in solution processing technology, where their processability is significantly affected.

[0003] Although MOFs and COFs show some solution processing capabilities to some extent through methods such as stripping or introduction of charges, organic frameworks based on non-covalent bonds, such as hydrogen-bonded organic frameworks (HOFs) and supramolecular organic frameworks (SOFs), generally show better solubility. Among them, HOFs can be easily recrystallized from solution. However, there are relatively few studies on their periodic structures in solution. Therefore, developing a reliable strategy to construct soluble organic frameworks with stable periodic structures is crucial to promote their applications that require solution processing technology.

[0004] Recently, halogen-bonded organic frameworks (XOFs) have attracted extensive attention as a new type of supramolecular framework material. It is worth noting that some XOFs based on the unique three-center four-electron [NX + -N] halogen bonds have been successfully developed to develop specific functions such as fatty acid vapor adsorption, halogenation reaction and catalysis. The presence of halide cations (halogen I) in the framework of this type of material makes it a unique cationic organic framework that can show slight solubility in polar solvents. These [NX + The excellent directionality and stability of the [-N] halogen bonds enable XOFs to maintain their periodic framework structure even in the solution phase, which provides potential possibilities for their application in solution processing technology.

[0005] Although XOFs show good prospects in terms of functionality and application potential, their application in solution processing technology still faces multiple technical challenges. The first is their insufficient solubility. Although XOFs have unique [NX + -N] The halogen bond structure has solubility to a certain extent, but its overall solubility is still limited, especially in certain specific solvents. This deficiency seriously restricts its handling and processing capabilities in liquid environments. Therefore, how to effectively improve the solubility of XOFs has become a key technical issue in realizing its wide application. The second is structural stability. During solution processing, it is crucial to maintain the periodic framework structure of XOFs. Many existing framework materials will undergo structural collapse in solution due to environmental changes, resulting in performance degradation. Therefore, the development of organic framework materials that can maintain a stable structure under a variety of solvent conditions is a challenge that needs to be solved urgently. Finally, there is functional customization. The functionality of XOFs is closely related to its structure. How to achieve customization of specific functions (such as piezoelectricity, adsorption or catalysis) through the rational design and synthesis of new halogen bond organic frameworks is the key to improving the application value of materials. It is necessary to explore how to introduce new functional groups or structural units without affecting the stability of the framework.

[0006] In summary, if the solubility, structural stability and multifunctional properties of XOFs can be further improved through reasonable design, they will become ideal candidate materials for devices and sensors that rely on solution processing technology, which will have positive significance for expanding their applications. Summary of the invention

[0007] In view of the above-mentioned defects of the prior art, in a first aspect of the present invention, a method for preparing a solution-processable two-dimensional halogen bond organic framework with high synthesis efficiency and reduced production cost is provided, comprising the following steps: (1) 7-tridecanone, NH 4 OAc, NaBH 3 CN is added to the solvent to form a mixed solution, and the mixed solution is reacted under a protective atmosphere. After completion, the product is recovered to obtain compound 1, i.e., N-(1-hexylheptyl)amine; (2) mixing perylene-3,4,9,10-tetracarboxylic dianhydride, compound 1, and imidazole, and then reacting them under a protective atmosphere, and after completion, recovering the product to obtain compound 2; (3) [Cp*RhCl 2 ] 2 、AgSbF 6 and solvent were mixed under protective atmosphere, followed by addition of compound 2, NIS, Cu(OAc) 2 and a solvent to carry out a reaction, and after completion, recover the product to obtain compound 3; (4) Compound 3, 4-pyridylboronic acid, Cs 2 CO 3 、Pd(PPh 3 ) 4 Add to the solvent, react under a protective atmosphere, and after completion, recover the product to obtain PDI; (5) AgBF 4 , PDI, and iodine are dissolved in a solvent to form a corresponding solution, and then the PDI solution is added to the AgBF 4 In the solution, an iodine solution is added to the obtained solution after mixing to carry out a reaction, and after completion, the product is recovered to obtain XOF-PDI, that is, a solution-processable two-dimensional halogen bond organic framework.

[0008] Compound 1 and Compound 2 were synthesized based on the method provided in the literature (J. Am. Chem. Soc. 2020, 142, 4, 1686-1691). Correspondingly, in the synthesis step of Compound 1, the amount of 7-tridecanone was 21.2 mmol, NH 4 The amount of OAc used was 211 mmol, NaBH 3 The amount of CN used was 21.2 mmol; the solvent included methanol, and the amount of the solvent used was 80 mL. The reaction of this step was carried out at room temperature for 48 h.

[0009] In this field, the recovery of products generally includes operations such as separation and purification of products, so technicians can use general technical means in the field to achieve this purpose. For specific operational aspects, for example, when compound 1 is synthesized under laboratory conditions, thin-layer chromatography (TLC) can be used to detect the complete disappearance of the raw materials (color development by anisaldehyde), and then the reaction is terminated by dropwise addition of concentrated hydrochloric acid, followed by concentration under reduced pressure, and the resulting solid is dispersed in water and adjusted to alkalinity with aqueous sodium hydroxide solution, and then the mixture is extracted with dichloromethane, the organic phases are combined and washed with brine, and then dried, filtered, and the solvent is removed under reduced pressure to obtain compound 1. Those skilled in the art can also choose other suitable methods according to the actual scale and conditions of the synthesis.

[0010] In the synthesis step of compound 2, the amount of perylene-3,4,9,10-tetracarboxylic dianhydride used is 0.76 mmol, the amount of compound 1 used is 1.91 mmol, and the amount of imidazole used is 55.44 mmol. The reaction temperature of this step is 180°C, and the reaction time is 4.5 h.

[0011] For the specific operation level, for example, compound 2 is synthesized under laboratory conditions. After the reaction is completed, the reaction mixture can be cooled to near room temperature, diluted with ethanol, and then hydrochloric acid is added and allowed to stand for precipitation. The resulting precipitate is collected by suction filtration, washed with distilled water and dried under reduced pressure to obtain a crude product. Finally, flash column chromatography is used on a silica gel column chromatography with dichloromethane / ethanol as the eluent to obtain compound 2. Those skilled in the art can also select other suitable methods according to the scale and conditions of the actual synthesis.

[0012] Compounds 3 and 4 were synthesized based on the method provided in the literature (Org. Lett. 2017, 19, 5438−5441). Accordingly, in the synthesis step of compound 3, [Cp*RhCl 2 ] 2 The dosage is 0.014 mmol, AgSbF 6 The amount of was 0.17 mmol, the amount of compound 2 was 0.19 mmol, the amount of NIS was 1.53 mmol, and Cu(OAc) 2 The amount of the solvent is 0.77 mmol; the solvent includes dichloroethane, and the total amount of the solvent is 8 mL. The reaction temperature of this step is 80 ° C, and the reaction time is 96 h.

[0013] For the specific operation level, for example, in the synthesis of compound 3 under laboratory conditions, after the reaction is completed and cooled to room temperature, the resulting reaction mixture is diluted with a solvent and saturated with Na 2 S 2 O 3 The product was purified by silica gel column chromatography using dichloromethane / petroleum ether as eluent. Finally, compound 3 was obtained by recrystallization through chloroform / methanol. Those skilled in the art may also select other suitable methods according to the actual scale and conditions of the synthesis.

[0014] In the synthesis step of compound 4, the amount of compound 3 used was 0.16 mmol, the amount of 4-pyridylboronic acid used was 1.88 mmol, and Cs 2 CO 3 The dosage is 3.13 mmol, Pd(PPh 3 ) 4 The dosage is 0.03 mmol, the solvent type and volume ratio is toluene:methanol:water=4:1:1, and the solvent dosage is 20-100 mL. The reaction temperature of this step is 85 °C, and the reaction time is 48 h.

[0015] For specific operation, for example, in the synthesis of PDI under laboratory conditions, after the reaction is completed and cooled to room temperature, the product can be concentrated and then purified by flash column chromatography using CH 2 Cl 2 / CH 3 PDI can be obtained by purifying with OH / TEA as eluent. Those skilled in the art can also select other appropriate methods according to the actual scale and conditions of synthesis.

[0016] Preferably, in step (5), 0.10-0.50 mmol AgBF 4 Dissolve in 1-10 mL solvent to obtain AgBF 4 Solution.

[0017] Preferably, in step (5), 0.05-0.25 mmol PDI is dissolved in 1-10 mL solvent to obtain a PDI solution.

[0018] Preferably, in step (5), 0.10-0.5 mmol of iodine is dissolved in 1-10 mL of solvent to obtain an iodine solution.

[0019] Preferably, in step (5), the type of solvent includes methanol.

[0020] Preferably, in step (5), the mixing treatment is carried out at room temperature for 1-5 h.

[0021] Preferably, in step (5), the reaction is carried out at room temperature and the reaction time is 1-3 days.

[0022] For specific operation, such as synthesizing XOF-PDI under laboratory conditions, it is appropriate to add the PDI solution to the AgBF by dropwise addition. 4 After the reaction, the solvent is evaporated under reduced pressure without heating, and the precipitate is dried overnight in a vacuum. Then, it is dispersed in 1,2-dichloroethane by ultrasonic treatment, and finally dried in a vacuum to obtain XOF-PDI. Those skilled in the art can also choose other suitable methods according to the actual scale and conditions of the synthesis.

[0023] The main synthesis process of the present invention is as follows:

[0024]

[0025]

[0026] .

[0027] As shown above, the present invention simplifies the synthesis process, and the optimized synthesis route will greatly simplify the production process of XOFs, improve synthesis efficiency, and reduce production costs. This will lay the foundation for large-scale industrial production and promote the commercialization of such materials. In addition, the preparation focuses on the selection of environmentally friendly solvents and materials during the synthesis and processing process, which helps to reduce the impact on the environment and promote the practice of green chemistry.

[0028] In the second aspect of the present invention, a solution-processable two-dimensional halogen-bonded organic framework with high solubility, strong structural stability and multifunctional properties is provided, which is prepared by the preparation method provided by the first aspect of the present invention.

[0029] In the third aspect of the present invention, there is provided an application of the solution-processable two-dimensional halogen-bonded organic framework according to the second aspect of the present invention, specifically, an application as a raw material in the preparation of sensors and electronic devices.

[0030] Based on the above technical scheme, the inventive concept and principle of the present invention is to significantly enhance the solubility of XOFs by introducing long-chain alkyl side chains and optimizing solvent selection, so that it can maintain good dispersibility in a variety of solvents: (1) Increase intermolecular interactions in a solvent-repellent environment: Long-chain alkyl side chains have strong hydrophobicity and can form a stable hydrophobic effect in a solvent environment, thereby enhancing the solubility of the framework material in solvents of different polarities. This design enables the framework material to have good solubility in both polar and non-polar solvents.

[0031] (2) Reduce molecular stacking: The alkyl side chain has a large volume, which can effectively increase the molecular distance of the framework material and reduce the π-π stacking effect between molecules. This effect of reducing stacking not only improves solubility, but also preserves the structural integrity of the material, which is conducive to the periodic stable structure in the solution.

[0032] (3) Improved flexibility and solution stability: The long-chain alkyl side chain introduces a certain degree of flexibility to the overall molecular structure, allowing the framework material to be more stably dispersed in the solvent. In addition, this flexibility also increases the fluidity of the material in the solution, further enhancing its solubility.

[0033] Therefore, the two-dimensional halogen-bonded organic framework can be dissolved in most organic solvents, such as high-boiling point solvents such as DMSO and DMF, alcohol solvents such as ethanol and methanol, and halogenated solvents such as dichloromethane and dichloroethane.

[0034] This progress will greatly expand the application scope of XOFs in liquid phase processing technology. In addition, through cross-linking strategies and the introduction of functional groups, the structural stability of XOFs in solution environments is improved to ensure that their periodic structure does not collapse during processing and application.

[0035] In the present invention, PDI (Perylene Diimide) is one of the core functional groups. The structure of PDI has a planarized large π-electron conjugated system, which gives it high electron affinity and excellent optoelectronic properties, making it extremely valuable in electronic and optical applications. In XOF-PDI, PDI not only provides a strong π-π stacking ability, but also further regulates the solubility and structural stability of the framework material by introducing long-chain alkyl side chains.

[0036] The XOF-PDI of the present invention achieves unique effects through the following mechanisms, which are specifically embodied in: (1) Structural stability achieved through halogen bonds: Halogen bonds in XOF-PDI [NX + -N] binding provides strong intermolecular directionality, ensuring the stability of the periodic structure of the framework in solution.

[0037] (2) π-π stacking regulation based on PDI: The π-π stacking property of PDI enables XOF-PDI to have electron transport capabilities that are not available in the existing technologies (CN202311292812, CN202311783696). Due to the introduction of long-chain alkyl side chains, this stacking can be finely controlled, avoiding the decrease in solubility caused by excessive stacking, thereby effectively improving the processability of the framework material and the maintainability of the periodic structure in solution.

[0038] Improved solubility and adaptability to solution processing: Through side chain engineering, the solvophobic effect of the long-chain alkyl enhances the dispersibility of the framework in solvents of different polarities, making XOF-PDI exhibit good adaptability to solution processing. This effect is not seen in the above-mentioned prior art of the inventor's research group, and this characteristic is the basis for the invention to have a wide range of application potentials in the fields of sensors and flexible electronics.

[0039] The above effects help improve the long-term reliability and performance consistency of the material. In addition, the present invention also introduces specific functional groups into the framework to give XOFs multiple functions, such as excellent piezoelectricity, conductivity and catalytic performance. This will make these materials have higher added value in applications such as sensors, electronic devices and catalytic reactions.

[0040] With good solubility and stability, XOFs can be combined with other materials (such as polyvinylidene fluoride PVDF) to prepare high-performance flexible sensors and electronic devices, broadening its application prospects in the fields of electronics and sensors. Through close connection with the industrial chain, this invention effectively transforms research results into market products and achieves a smooth transition from laboratory to market. This will accelerate the promotion of XOFs in practical applications and bring new technology and product innovations to related industries.

[0041] Compared with the prior art, the present invention has the following advantages and beneficial effects: The invention provides a method for preparing a solution-processable two-dimensional halogen bond organic framework, which has the advantages of high synthesis efficiency and reduced production cost.

[0042] The invention provides a solution-processable two-dimensional halogen bond organic framework, which has high solubility, strong structural stability and multifunctional characteristics.

[0043] The invention provides an application of a solution-processable two-dimensional halogen-bonded organic framework, which has broad prospects in the fields of electronics and sensors. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 For PDI and XOF-PDI in dimethyl sulfoxide-d6 (600 MHz, 298 K) 1 H NMR spectrum; Figure 2 I 3d X-ray photoelectron spectroscopy (XPS) of XOF-PDI; Figure 3 From left to right in the figure are the N 1s XPS spectra of PDI and XOF-PDI; Figure 4 is the Raman spectrum of XOF-PDI under 532 nm laser excitation; Figure 5 Dynamic Light Scattering (DLS) images of PDI and XOF-PDI and the dissolution process of XOF-PDI in methanol; Figure 6 Schematic diagram of the manufacturing process of XOF-PDI / PVDF flexible piezoelectric sensor; Figure 7 From left to right in the figure are the schematic diagram of medium-voltage power sensing in human motion, the optical image and output voltage generated by human wrist bending motion, and the optical image and output voltage generated by human elbow bending motion; Figure 8 For [NI + -N] Schematic diagram of the construction of connected XOF-PDI and the fabrication of flexible devices by solution processing. DETAILED DESCRIPTION

[0045] The present invention is further described below by way of examples, but the present invention is not limited to the scope of the examples. The experimental methods in the following examples without specifying specific conditions are carried out according to conventional methods and conditions, or selected according to the product specifications.

[0046] Example 1 A method for preparing a solution-processable two-dimensional halogen-bonded organic framework, comprising the following steps: (1) Place a magnetic stirrer in a 250 mL round-bottom flask and add 7-tridecanone (4.2 g, 21.2 mmol), NH 4 OAc (16.3 g, 211 mmol) and NaBH 3 CN (1.33 g, 21.2 mmol) was dissolved in 80 mL of methanol under argon protection; the mixture was stirred at room temperature for 48 h until TLC showed that the starting material disappeared completely (color development by anisaldehyde), and then the reaction was terminated by dropwise addition of concentrated hydrochloric acid; the reactants were concentrated under reduced pressure, and the resulting solid was dispersed in 250 mL of water and adjusted to pH = 10 with saturated aqueous NaOH; the mixture was extracted with dichloromethane, the organic phases were combined and washed with brine, and then MgSO 4 After drying and filtering, the solvent was removed under reduced pressure to obtain compound 1, i.e., N-(1-hexylheptyl)amine, which was directly used in the next reaction without further purification; (2) Perylene-3,4,9,10-tetracarboxylic dianhydride (0.30 g, 0.76 mmol), compound 1 (0.38 g, 1.91 mmol) and imidazole (3.8 g, 55.44 mmol) were added to a 100 mL round-bottom flask and protected with argon. The reaction mixture was stirred at 180 °C for 4.5 h. After the reaction mixture was cooled to near room temperature, it was diluted with ethanol, and then hydrochloric acid (2 mol / L, 50 mL) was added and allowed to stand for 1 h. The resulting precipitate was collected by suction filtration, washed with distilled water and dried under reduced pressure to obtain a crude product. The dark red powder of compound 2 (0.32 g, yield 60%) was obtained by flash column chromatography on silica gel column chromatography using dichloromethane / ethanol as eluent. (3) Place a magnetic stirrer in a 50 mL Schlenk tube and add [Cp*RhCl 2 ] 2 (0.014 mmol, 8.9 mg) and AgSbF 6 (0.17 mmol, 59.4 mg) was dissolved in dry dichloroethane (4.0 mL) and stirred at room temperature for 30 min. Then compound 2 (0.19 mmol, 145.0 mg), NIS (1.53 mmol, 345.6 mg), Cu(OAc) were added in sequence. 2(0.77 mmol, 139.5 mg) and dry dichloroethane (4.0 mL), sealed the tube and stirred at 80 °C for 96 h; after the reaction was cooled to room temperature, CH 2 Cl 2 The reaction mixture was diluted and washed with saturated Na 2 S 2 O 3 The combined organic layers were washed with brine and MgSO 4 The product was dried and purified by silica gel column chromatography using dichloromethane / petroleum ether as eluent, and finally recrystallized from chloroform / methanol to obtain compound 3 (196 mg, yield 81%); (4) Compound 3 (0.19 g, 0.16 mmol), 4-pyridylboronic acid (0.23 g, 1.88 mmol), and anhydrous Cs 2 CO 3 (1.02 g, 3.13 mmol) and Pd(PPh 3 ) 4 (36.2 mg, 0.03 mmol), stirred at 85 °C for 48 h; after the reaction was cooled to room temperature, the product was concentrated to obtain a crude product, which was purified by flash column chromatography using CH 2 Cl 2 :CH 3 OH:TEA (80:1:0.5, v / v) was used as the eluent to obtain red powdered PDI (0.15 g, yield 60%); (5) AgBF 4 After dissolving (18.3 mg, 0.10 mmol) in 1 mL of methanol, it was added dropwise to a 1 mL methanol solution of PDI (50.0 mg, 0.05 mmol), stirred at room temperature for 1 h, and then a solution of iodine (23.9 mg, 0.10 mmol) dissolved in 1 mL of methanol was added to the solution, and the solution was allowed to stand at room temperature for 3 d. The solvent was evaporated under reduced pressure without heating, and the precipitate was dried in a vacuum overnight. Then, it was ultrasonically dispersed at 50 °C, heated to 110 °C after 24 hours, and dispersed in 1,2-dichloroethane for 3 h, and finally vacuum dried to obtain XOF-PDI, a solution-processable two-dimensional halogen-bonded organic framework.

[0047] Example 2 This example characterizes the structure of the prepared XOF-PDI. 1 The formation process of XOF-PDI was monitored by H NMR spectroscopy. Figure 1When PDI coordinates with Ag+ / I+ to form MOF-PDI and XOF-PDI, it will cause a significant disturbance in the magnetic environment of PDI. After the formation of XOF-PDI, the Ha and Hb peaks show obvious low-field shifts (ΔδHa = 0.151 ppm, ΔδHb = 0.238 ppm), which is attributed to [NI + The electron density of the pyridine ring decreases when the [-N] halogen bond is formed. In contrast, the Hc signal shift on the internal aromatic ring is smaller (ΔδHc = 0.004 ppm) because it is farther away from the pyridine ring and is less affected by the change in electron density.

[0048] Example 3 In this embodiment, X-ray photoelectron spectroscopy is used to further analyze the surface chemical states of XOF-PDI and PDI. The I 3d XPS spectrum of XOF-PDI is shown in FIG. Figure 2 XPS shows two I 3d main peak signals, at 623.0 eV (I 3d 5 / 2 ) and 634.4eV (I 3d 3 / 2 ), which indicates the presence of I+ ions and corresponds to the presence of iodine in [NI + -N] spin-orbit splitting in halogen bonds.

[0049] The N 1s XPS spectra of PDI and XOF-PDI are as follows: Figure 3 XPS analysis also shows that from PDI to XOF-PDI, the N 1s binding energy gradually increases with the addition of I+, which is consistent with the decrease in the electron cloud density of the pyridine ring. No Ag 3d signal was detected in XPS, confirming the complete removal of Ag+, which was attributed to the filtration separation of insoluble AgI.

[0050] It should be noted that the above effects are different from the effects of the prior research of the inventor's research group (CN202311783696) as follows: Improvement of crystallinity and structural stability: The literature mentions that high crystallinity can be obtained by improving the preparation process, but without using the same approach, the present invention achieves this by [NX + The three-center four-electron combination of the [-N] halogen bond makes the material's crystallinity and framework structure more stable. The introduction of long-chain alkyl side chains further reduces the effects of molecular stacking and π-π stacking effects on the crystal structure, thereby improving the overall crystallinity while still maintaining its periodicity in solution.

[0051] Versatility granted by side chain engineering: The side chain engineering of the present invention not only improves the crystallinity and solubility of the material, but also further expands its adaptability in solution processing. This molecular design-based solubility improvement provides new possibilities for the subsequent application of XOFs, such as application in solution-based flexible electronic devices, which is a functional advantage that has not been realized in the literature.

[0052] Example 4 This example verifies the structure and solubility of XOF-PDI. First, the Raman spectrum of XOF-PDI under 532 nm laser excitation is characterized. Figure 4 The Raman spectrum of XOF-PDI shows that -1 The obvious G peak at , similar to the E2g mode of graphene, confirms the existence of two-dimensional structure in XOF-PDI.

[0053] XOF-PDI was measured using dynamic light scattering. Figure 5 The results show that the particle size of XOF-PDI in methanol solution increases, which also supports the formation of a two-dimensional framework structure. The photo in the figure reflects the dissolution process of XOF-PDI in methanol with Tyndall effect.

[0054] The excellent solubility of XOF-PDI is attributed to the combination of side chain engineering and electrostatic repulsion (the introduced alkyl side chains and charged [NI + -N] halogen bond), which makes it show excellent solubility in various organic solvents, demonstrating the successful preparation of a new type of solution-processable XOF material.

[0055] Example 5 In this example, sensors and electronic components were prepared using XOF-PDI as a raw material to study their effects in practical applications.

[0056] The steps for preparing PVDF naturally evaporated film are as follows: 2.0 g of PVDF was dissolved in 10 mL of a mixed solution of DMF and acetone (2:3, v / v). After ultrasonic dispersion, the solution was poured into a 30 cm diameter Petri dish and naturally evaporated at 60 °C for 2 days to form a complete film.

[0057] Preparation of XOF-PDI / PVDF composite electrospinning films, such as Figure 6 As shown, the steps are as follows: A mixed solvent was prepared using DMF and acetone in a volume ratio of 4:6. 1.0 g of PVDF was dispersed in the mixed solvent. After ultrasonic treatment for 1 h, 40.0 mg of XOF-PDI was added and ultrasonic treatment was continued for 0.5 h. Then, the fibers were collected by electrospinning at a feed rate of 1 mL / h, a distance of 15 cm between the needle tip and the collector, a voltage of 20 kV, an environmental condition of 25±2°C and 50%±5% humidity, and a collector speed of 600 rpm. After spinning, the film was dried at 60°C to remove residual solvent.

[0058] Preparation and testing of piezoelectric sensors: The XOF-PDI / PVDF composite electrospun film was sandwiched between two electrodes, and the triboelectric signal interference was avoided by using aluminum foil. The wires of the upper and lower electrodes were connected and encapsulated with Kapton tape. The flexible sensors made of XOF-PDI / PVDF composite materials were placed on different parts of the human body (such as joints, wrists, and elbows). Make sure that the outside of the sensor is in contact with the stretched part and the inside is in contact with the compressed part so that positive and negative signals can be captured.

[0059] Sensor signal test: Schematic diagram of medium-voltage power sensing in human motion, as well as the optical image and output voltage generated by human wrist bending motion, and the test results of the optical image and output voltage generated by human elbow bending motion are shown in Figure 1. Figure 7 shown.

[0060] For testing at a joint: Monitor the positive signal from the outside sensor when the joint is moved and the negative signal from the inside sensor when pressure is applied.

[0061] For wrist testing: Place the sensor on your wrist, move your wrist back and forth, and observe the corresponding positive and negative signals generated by the sensor.

[0062] For testing at the elbow: Place the sensor on the inside of the elbow and record the negative signal produced by the sensor as the arm is raised. Note the significant increase in the elbow signal compared to the wrist signal, indicating that the elbow is subject to greater mechanical forces.

[0063] [NI + -N] The construction of XOF-PDI and the fabrication of flexible devices by solution processing are shown in Figure 8As shown, combined with the above test results, the present invention significantly enhances the solubility of XOFs by introducing long-chain alkyl side chains and optimizing solvent selection, so that it can maintain good dispersibility in a variety of solvents. Greatly expand the scope of application of XOFs in liquid phase processing technology. In addition, through cross-linking strategies and the introduction of functional groups, the structural stability of XOFs in a solution environment is improved to ensure that its periodic structure does not collapse during processing and application. This will help improve the long-term reliability and performance consistency of the material. Not only that, the present invention also gives XOFs a variety of functions, such as excellent piezoelectricity, conductivity and catalytic properties, by introducing specific functional groups into the framework. This will give these materials higher added value in applications such as sensors, electronic devices and catalytic reactions.

[0064] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A method for preparing a solution-processable two-dimensional halogen-bonded organic framework, characterized in that: The steps include: (1) adding 7-tridecanone, NH4OAc and NaBH3CN to a solvent to form a mixed solution, and reacting the mixed solution under a protective atmosphere. After completion, recovering the product to obtain compound 1, i.e., N-(1-hexylheptyl)amine; (2) mixing perylene-3,4,9,10-tetracarboxylic dianhydride, compound 1, and imidazole, and then reacting them under a protective atmosphere, and after completion, recovering the product to obtain compound 2; (3) [Cp*RhCl2]2, AgSbF6 and solvent are mixed under a protective atmosphere, and then compound 2, NIS, Cu(OAc)2 and solvent are added and reacted. After completion, the product is recovered to obtain compound 3; (4) Add compound 3, 4-pyridylboronic acid, Cs2CO3, and Pd(PPh3)4 to a solvent, react under a protective atmosphere, and after completion, recover the product to obtain PDI; (5) AgBF4, PDI and iodine are dissolved in solvents to form corresponding solutions, and then the PDI solution is added to the AgBF4 solution. After mixing, the iodine solution is added to the resulting solution to react. After completion, the product is recovered to obtain XOF-PDI, which is a solution-processable two-dimensional halogen bond organic framework.

2. The method for preparing a solution-processable two-dimensional halogen-bonded organic framework according to claim 1, characterized in that: In the step (5), 0.10-0.50 mmol of AgBF4 is dissolved in 1-10 mL of solvent to obtain an AgBF4 solution.

3. The method for preparing a solution-processable two-dimensional halogen-bonded organic framework according to claim 1, characterized in that: In the step (5), 0.05-0.25 mmol PDI is dissolved in 1-10 mL solvent to obtain a PDI solution.

4. The method for preparing a solution-processable two-dimensional halogen-bonded organic framework according to claim 1, characterized in that: In the step (5), 0.10-0.5 mmol of iodine is dissolved in 1-10 mL of solvent to obtain an iodine solution.

5. The method for preparing a solution-processable two-dimensional halogen-bonded organic framework according to claim 1, characterized in that: In the step (5), the type of solvent includes methanol.

6. The method for preparing a solution-processable two-dimensional halogen-bonded organic framework according to claim 1, characterized in that: In the step (5), the mixing process is carried out at room temperature for 1-5 h.

7. The method for preparing a solution-processable two-dimensional halogen-bonded organic framework according to claim 1, characterized in that: In the step (5), the reaction is carried out at room temperature and the reaction time is 1-3 days.

8. A solution processable two-dimensional halogen bond organic framework, characterized in that: The method is prepared according to any one of claims 1 to 7.

9. A use of the solution-processable two-dimensional halogen-bonded organic framework as claimed in claim 8, characterized in that: Used as raw materials in the preparation of sensors and electronic devices.

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