Preparation method of chiral aldehyde amine condensation covalent organic framework material and application thereof

Abstract

The application discloses a preparation method of a chiral aldehyde amine condensation covalent organic framework material and application thereof, and by means of an ultrasonic chemical synthesis method, the synthesis cost and energy consumption are remarkably reduced, the reaction time is shortened, and the chiral transmission efficiency and the crystallinity of the material are greatly improved; the synthesis method has the characteristics of high efficiency and green environmental protection, and further provides a novel technical means for preparing a high-performance chiral two-dimensional COF material with controllable structure; by the application, the preparation of the chiral two-dimensional COF material becomes more efficient, stable, and has high repeatability and controllability, and is suitable for being widely applied to various technical fields requiring high-chirality materials, and further promotes the development of chiral materials in scientific research and industrial application.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of covalent organic framework materials, and particularly relates to a preparation method and application of a chiral aldehyde amine condensation covalent organic framework material. BACKGROUND

[0002] Covalent organic frameworks (COFs) are a class of ordered porous structures formed by organic molecules through covalent bonds, possessing high specific surface area, good chemical stability, and excellent optoelectronic properties. Due to their unique properties, COFs have shown great potential in various fields such as gas storage, separation, catalysis, and sensors. Chirality is crucial in chemistry and biology, as many biological molecules have specific chiral forms that play key roles in drug activity, metabolism, and biocompatibility.

[0003] Chiral covalent organic frameworks (COFs) have shown outstanding performance in the application of chiral materials, such as in chromatographic separation technology. Compared to traditional chiral polymer stationary phases, they provide more significant advantages. They have precise and regular pore structures, which not only provide consistent and predictable separation effects, but also have higher efficiency in loading and mass transfer rate due to their low density, high specific surface area, and high porosity. In addition, the chemical and thermal stability of COFs allows them to maintain performance stability in a wide temperature range and different chemical environments, which is crucial for the long-term operation of chromatographic stationary phases. The diversity of building units and the functional adjustability of COFs allow their pore size and chemical properties to be customized by changing the monomers or synthesis conditions to meet various chiral separation needs. The feature of easy post-modification further enhances the chiral recognition ability of COFs, making them have potential advantages in the recognition and separation efficiency of chiral molecules. Therefore, chiral COFs, due to their unique structure and performance, show a broader prospect than ordinary chiral polymers in the application of chiral stationary phases.

[0004] In the field of synthesis of chiral covalent organic frameworks (COFs), the hydrothermal synthesis method is currently the mainstream technology. However, this method has several limitations, mainly including the following problems: (1) harsh synthesis conditions: traditional solvent thermal method usually requires high temperature and high pressure conditions (120-200℃), long synthesis time (2-7 days), and the use of toxic organic solvents, the operation process is complex and there is a certain safety risk; (2) low chiral transfer efficiency: although there is a method of directly adding chiral molecules to induce chiral COFs by hydrothermal method, but this method often leads to uneven distribution of chiral induction rate, and low chiral transfer efficiency; (3) difficult to control the reaction: the existing method is complex in the control of reaction conditions, it is difficult to realize efficient chiral induction and stable product consistency, which limits the popularization of the material in practical application. Although the hydrothermal method realizes the chiral induction, but the chiral transfer efficiency is not high, and the control of reaction conditions is relatively complex, it is difficult to realize efficient chiral induction and product consistency.

[0005] How to develop an economic and environmentally friendly synthesis strategy to realize the efficient synthesis of COFs with high chiral activity is a problem to be solved at present, which needs to reduce the synthesis cost while ensuring the chiral purity, and reduce the impact on the environment, and improve the green level of the reaction. In addition, the new synthesis method should also have good crystallinity and reaction controllability to ensure the stability and selectivity of the obtained COFs material, which is crucial for their performance in chiral separation, asymmetric catalysis and other applications. At the same time, this method should also have universality, which can be applied to the synthesis of various COFs to meet the needs of different application scenarios. In summary, the development of such a synthesis method will greatly promote the industrialization process of chiral COFs, and bring far-reaching influence to the field of chemistry and biology. SUMMARY

[0006] This section is intended to summarize some aspects of the embodiments of the present application and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the abstract and title of the specification of the present application to avoid obscuring the purpose of this section, abstract and title, and such simplifications or omissions cannot be used to limit the scope of the present application.

[0007] In view of the above and / or problems existing in the prior art, the present application is proposed.

[0008] Therefore, the purpose of the present application is to overcome the deficiencies in the prior art, and to provide a preparation method of chiral aldehyde amine condensation covalent organic framework material.

[0009] To solve the above technical problems, the present application provides the following technical scheme: a preparation method of chiral aldehyde amine condensation covalent organic framework material, characterized in that: comprising,

[0010] introducing chirality: dissolving organic monomer 1 and a chiral inducer in an aqueous acetic acid solution, and performing ultrasonic treatment to obtain a mixed solution;

[0011] introducing a second organic monomer and prolonging ultrasonic treatment: adding organic monomer 2 to the mixed solution, and performing ultrasonic treatment for 40-120 minutes;

[0012] product separation and purification: after the ultrasonic treatment is completed, the reaction mixture is separated by suction filtration;

[0013] The organic monomer 1 includes but is not limited to one or more of triformylphloroglucinol, p-xylylene, 2,5-dihydroxy-p-xylylene, and 4,4'-diphenyl dimethyl formaldehyde; and the organic monomer 2 includes but is not limited to one or more of 1,3,5-tris(4-aminophenyl)benzene, 2,4,6-tris(4-aminophenyl)-1,3,5-triazine, and benzidine.

[0014] As a preferred scheme of the preparation method, the aqueous acetic acid solution has a concentration of 6-12 mol / L.

[0015] As a preferred scheme of the preparation method, the ultrasonic probe used in the ultrasonic treatment in the step of introducing chirality has a diameter of 2-10 mm.

[0016] As a preferred scheme of the preparation method, the chiral inducer is one or more of (R)-(+)-α-methylbenzylamine, (S)-(+)-α-methylbenzylamine, (R)-(+)-1-(1-naphthyl)ethylamine, (S)-(+)-1-(1-naphthyl)ethylamine, L-tryptophan, D-tryptophan, L-lysine, D-lysine, (R)-2-(1-aminoethyl)phenol, and (S)-2-(1-aminoethyl)phenol.

[0017] As a preferred scheme of the preparation method, the molar ratio of the organic monomer 1 to the chiral inducer is 1:1-5.

[0018] As a preferred scheme of the preparation method, the amount of the aldehyde group in the organic monomer used in the reaction to the amount of the amino group is 1:1.

[0019] As a preferred scheme of the preparation method, the ultrasonic probe used in the ultrasonic treatment in the step of introducing chirality has a diameter of 6 mm.

[0020] As a preferred scheme of the preparation method, in the step of introducing chirality, the ultrasonic treatment is performed at a power of 30-70% for 10-30 minutes.

[0021] As a preferred scheme of the preparation method, in the prolonged ultrasonic treatment, the ultrasonic frequency is kept at 40 kHz, and the power is 30-70%.

[0022] The present application has the following advantages:

[0023] 1. The present application innovatively utilizes ultrasonic energy to make the mixture of reactants more uniform, thereby realizing the uniform induction of the chiral auxiliary to the COF material framework; in the reaction process, the ultrasonic wave accelerates the uniform dispersion of the material, so that the chiral auxiliary can uniformly induce the chiral structure of the entire material without being embedded in the final product, which significantly improves the chiral induction rate and the consistency of the material, and solves the problem of uneven chirality in the prior art.

[0024] 2. The present application greatly improves the synthesis efficiency of covalent organic framework (COF) materials by utilizing the high energy efficiency characteristics of ultrasonic waves; in traditional synthesis methods, such as solvothermal method, long-time (for example, 2-7 days) heating reaction under high temperature and high pressure conditions is usually required, and toxic organic solvents are often used, which not only limits the batch synthesis of COFs, but also brings safety and environmental risks; in contrast, the ultrasonic synthesis method is carried out in an aqueous system without the participation of organic solvents, and can be operated in room temperature air, which makes the synthesis process more green and environmentally friendly; the ultrasonic synthesis of the present application can significantly shorten the reaction time to within 1 hour, which not only greatly improves the efficiency of material preparation, but also greatly reduces the energy consumption.

[0025] 3. The present application realizes precise control of chiral two-dimensional COF materials, ensuring high crystallinity and high purity of the product. At the same time, the method has wide adaptability and can be compatible with a variety of different organic monomers and chiral auxiliaries, suitable for developing diversified functional chiral materials.

[0026] 4. The present application carries out the reaction at room temperature and under normal pressure through the action of ultrasonic waves, without the need for high temperature and high pressure or toxic and harmful solvents, which greatly simplifies the operation process, reduces the equipment and environmental requirements, and improves the experimental safety and green environmental protection.

[0027] 5. The method of the present application is not only suitable for laboratory-scale material preparation, but also has the potential for large-scale industrial application due to its simple operation, strong controllability and high efficiency; in the fields of catalysis, gas separation, drug delivery and chiral separation, chiral two-dimensional COF materials show a wide application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort on the basis of these drawings. Among them:

[0029] Figure 1 Fourier transform infrared spectrograms of COF TFP+DAB , R-MBA-COF TFP+DAB , and R-NEA-COF TFP+DAB in the present application comparative example 1.

[0030] Figure 2 Powder X-ray diffraction patterns of COF TFP+DAB , R-MBA-COF TFP+DAB , and R-NEA-COF TFP+DAB in the present application comparative example 1.

[0031] Figure 3 Circular dichroism spectrograms of S-MBA-COF TFP+DAB , R-MBA-COF TFP+DAB , S-NEA-COF TFP+DAB , and R-NEA-COF TFP+DAB in the present application comparative example 1.

[0032] Figure 4 Thermogravimetric analysis spectrograms of COF TFP+DAB , R-MBA-COF TFP+DAB , and R-NEA-COF TFP+DAB in the present application comparative example 1.

[0033] Figure 5 Scanning electron microscope images of COF TFP+DAB , R-MBA-COF TFP+DAB , and R-NEA-COF TFP+DAB in the present application comparative example 1.

[0034] Figure 6 Powder X-ray diffraction patterns of 1-L-alanine-COF DMTA+TAPB , 5-L-alanine-COF DMTA+TAPB , and COF DMTA+TAPB in the present application comparative example 2.

[0035] Figure 7 Fourier transform infrared spectrograms of 5 min-S-MBA-COF TFP+DAB , 10 min-S-MBA-COF TFP+DAB30 min-S-MBA-COF TFP+DAB , and 60 min-S-MBA-COF TFP+DAB Powder X-ray diffraction pattern.

[0036] Figure 8 For Comparative Example 5 of this invention, 5 min-S-MBA-COF TFP+DAB 10 min-S-MBA-COF TFP+DAB 30 min-S-MBA-COF TFP+DAB , and 60 min-S-MBA-COF TFP+DAB Fourier transform infrared spectrum. Detailed Implementation

[0037] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification.

[0038] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0039] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0040] Raw materials and reagents used in this invention:

[0041] The raw materials and reagents used in the present application are commercially available, including acetic acid, triformylphenol (TFP), terephthalaldehyde (TPA), 2,5-dihydroxyterephthalaldehyde (DHTA), 2,5-dimethoxybenzene-1,4-dicarboxaldehyde (DMTA), 4,4'-diphenyl dicarboxaldehyde (BDCA), (R)-(+)-α-methylbenzylamine (R-MBA), (S)-(+)-α-methylbenzylamine (S-MBA), (R)-(+)-1-(1-naphthyl)ethylamine (R-NEA), (S)-(+)-1-(1-naphthyl)ethylamine (S-NEA), (R)-(+)-α-methylbenzylamine (R-MBA), (S)-(+)-α-methylbenzylamine (S-MBA), (R)-(+)-1-(1-naphthyl)ethylamine (R-NEA), (S)-(+)-1-(1-naphthyl)ethylamine (S-NEA), L-alanine, p-phenylenediamine (DAB), 1,3,5-tris(4-aminophenyl)benzene (TAPB), 2,4,6-tris(4-aminophenyl)-1,3,5-triazine (TAPT), benzidine (BD), and the like.

[0042] Experimental methods used in the present application:

[0043] Method for preparing chiral aldehyde amine condensation covalent organic framework material:

[0044] 1. Introducing chirality (by combining aldehyde monomers with chiral molecules)

[0045] After weighing the organic monomer 1 and the chiral inducer in proportion, they are added to a 40 ml reaction vial, followed by the addition of 6 mol / L to 12 mol / L aqueous acetic acid as the reaction solvent. A 6 mm micro-tip probe is used for ultrasonic treatment, which is driven by a JY92-IIN type intelligent ultrasonic crusher of 650 W, operated at a frequency of 40 kHz in continuous mode for 10 minutes, with the power set to 50%;

[0046] 2. Introducing a second organic monomer and extending the ultrasonic treatment

[0047] The second organic monomer is added to the reaction mixture, and the ultrasonic treatment is continued for 60 minutes, further ensuring high crystallinity and chiral purity of the material by adjusting the reaction conditions;

[0048] 3. Product separation and purification

[0049] After the ultrasonic treatment, the reaction mixture was separated by suction filtration. First, the surface-attached by-products and unreacted precursors were removed by washing with acetone and methanol. Second, to further remove the residual precursors and impurities inside the pores of the COFs material, a Soxhlet extraction was performed using tetrahydrofuran for 24 hours. After washing and Soxhlet extraction, the material was further soaked in n-hexane for 24 hours to remove the possible residual small molecules. Finally, the residual solvents and small molecules were removed by freeze-drying treatment to ensure the integrity of the material structure.

[0050] Example 1

[0051] 1. A method for preparing a chiral two-dimensional covalent organic framework material (R-NEA-COF TFP+DAB ).

[0052] 2,4,6-triformylphloroglucinol (210 mg, 1 mmol) and R-NEA (171 mg, 1 mmol) were weighed into a 10 ml glass bottle, and 6 mol / L aqueous acetic acid solution (4 ml) was added;

[0053] The mixture was treated with ultrasonic using a 6 mm micro-tip probe, and a 650W JY92-IIN intelligent ultrasonic crusher was set to drive the probe at a power of 60% in continuous mode at 20 kHz for 10 minutes;

[0054] p-Phenylenediamine (162 mg, 1.5 mmol) was added to the mixed solution, and the ultrasonic treatment was continued for 60 min;

[0055] The yellow powder obtained after the reaction was collected by filtration with a 0.22 μm nylon membrane, and then washed with acetone and methanol in turn, followed by Soxhlet extraction with tetrahydrofuran, and finally dried under vacuum to obtain the chiral two-dimensional covalent organic framework material R-NEA-COF TFP+DAB .

[0056] Example 2

[0057] 1. A method for preparing a chiral two-dimensional covalent organic framework material (R-MBA-COF TFP+DAB ).

[0058] 2,4,6-triformylphloroglucinol (210 mg, 1 mmol) and R-MBA (119 mg, 1 mmol) were weighed into a 10 ml glass bottle, and 6 mol / L aqueous acetic acid solution (4 ml) was added;

[0059] The mixture was subjected to ultrasonic treatment using a microtip probe of 6 mm, and a 650W JY92-IIN type intelligent ultrasonic crusher was set to drive the probe to operate at a power of 60% in a continuous mode of 20 kHz for 10 minutes;

[0060] P-phenylenediamine (162 mg, 1.5 mmol) was added to the mixed solution, and the ultrasonic treatment was continued for 60 min;

[0061] The yellow powder obtained after the reaction was collected by filtration using a 0.22 μm nylon membrane, and the solid was washed with acetone and methanol in turn, then subjected to Soxhlet extraction with tetrahydrofuran, and finally dried under vacuum to obtain the chiral two-dimensional covalent organic framework material R-MBA-COF TFP+DAB product.

[0062] Comparative Example 1

[0063] 1. A method for preparing a two-dimensional covalent organic framework material (COF TFP+DAB ):

[0064] 2,4,6-triformylphloroglucinol (210 mg, 1 mmol) and p-phenylenediamine (162 mg, 1.5 mmol) were weighed into a 10 ml glass bottle, and 6 mol / L aqueous acetic acid solution (4 ml) was added;

[0065] The mixture was subjected to ultrasonic treatment using a microtip probe of 6 mm, and a 650W JY92-IIN type intelligent ultrasonic crusher was set to drive the probe to operate at a power of 60% in a continuous mode of 20 kHz for 60 minutes;

[0066] The yellow powder obtained after the reaction was collected by filtration using a 0.22 μm nylon membrane, and the solid was washed with acetone and methanol in turn, then subjected to Soxhlet extraction with tetrahydrofuran, and finally dried under vacuum to obtain the two-dimensional covalent organic framework material COF TFP+DAB product.

[0067] The R-NEA-COF TFP+DAB , R-MBA-COF TFP+DAB , and COF TFP+DAB prepared in Comparative Example 1 and Examples 1-2 were subjected to physicochemical property characterization and analysis, and the results are shown in Table 1. Figures 1-5

[0068] Figure 1 The Fourier transform infrared spectra of R-NEA-COF TFP+DAB , R-MBA-COF TFP+DAB , and COF TFP+DAB are shown. The stretching vibration peak of C=C (1579 cm -1 ​and the appearance of the vibration peak of CH-NH (1253 cm -1 ) proved the synthesis of chiral covalent organic frameworks.

[0069] Figure 2 R-NEA-COF TFP+DAB , R-MBA-COF TFP+DAB , and COF TFP+DAB . The diffraction peak around 5° shown in the image belongs to the (110) crystal plane of AA stacking. This indicates that the two-dimensional covalent organic framework prepared by the present application has strong crystallinity.

[0070] Figure 3 Circular dichroism spectra of S-MBA-COF TFP+DAB , R-MBA-COF TFP+DAB , S-NEA-COF TFP+DAB , and R-NEA-COF TFP+DAB .

[0071] As can be clearly seen from Figure 3 , the chiral covalent organic framework (COF) prepared by the present application exhibits excellent chiral characteristics. According to the CD data, the g lum value of (R / S)-MBA-COF TFP+DAB prepared by the present application is 0.718, and the g lum value of (R / S)-NEA-COF TFP+DAB is 0.089; the circular dichroism (CD) signal intensity can be as high as 160, while in previous studies, the chiral signal is usually not more than 50 (Xing Han et. al. Chiral induction in covalent organic frameworks, Nat. Commun. 9, 1294 (2018)). This significant improvement indicates that the product of the present application has obvious advantages in chiral characteristics.

[0072] Figure 4 Thermogravimetric analysis spectra of R-NEA-COF TFP+DAB , R-MBA-COF TFP+DAB , and COF TFP+DAB . These materials exhibit excellent thermal stability, further verifying that the two-dimensional covalent organic framework synthesized by the present application is indeed a two-dimensional covalent organic framework.

[0073] Figure 5 Thermogravimetric analysis spectra of R-NEA-COF TFP+DAB , R-MBA-COF TFP+DAB , and COF TFP+DABScanning electron microscope images. The COF material synthesized by the ultrasonic-assisted method presents as rods, and the π-π interaction between layers accelerates its crystallization process.

[0074] Example 3

[0075] 1. Preferred ratio of chiral inducer:

[0076] Method for preparing a chiral two-dimensional covalent organic framework material (1-L-alanine-COF DMTA+TAPB ).

[0077] Weigh 2,5-dimethoxybenzene-1,4-dicarboxaldehyde (112.8 mg, 0.58 mmol) and L-alanine (51.75 mg, 0.58 mmol) into a 10 ml glass bottle, and add 6 mol / L aqueous acetic acid (8 ml);

[0078] Ultrasonic treatment of the mixture is performed using a 6 mm micro-tip probe, and the 650W JY92-IIN intelligent ultrasonic crusher is set to drive the probe at a power of 60% in continuous mode at 20 kHz for 10 minutes;

[0079] 1,3,5-tris(4-aminophenyl)benzene (92.8 mg, 0.39 mmol) is added to the mixed solution, and ultrasonic treatment is continued for 60 min;

[0080] The yellow powder obtained after the reaction is filtered to collect the solid using a 0.22 μm nylon membrane, and sequentially washed with acetone and methanol, then Soxhlet extracted with tetrahydrofuran, and finally dried under vacuum to obtain the chiral two-dimensional covalent organic framework material L-alanine-COF DMTA+TAPB .

[0081] Example 4

[0082] 1. Method for preparing a chiral two-dimensional covalent organic framework material (5-L-alanine-COF DMTA+TAPB ).

[0083] Weigh 2,5-dimethoxybenzene-1,4-dicarboxaldehyde (112.8 mg, 0.58 mmol) and L-alanine (258.75 mg, 2.9 mmol) into a 10 ml glass bottle, and add 6 mol / L aqueous acetic acid (8 ml);

[0084] Ultrasonic treatment of the mixture is performed using a 6 mm micro-tip probe, and the 650W JY92-IIN intelligent ultrasonic crusher is set to drive the probe at a power of 60% in continuous mode at 20 kHz for 10 minutes;

[0085] 1,3,5-tris(4-aminophenyl)benzene (92.8 mg, 0.39 mmol) was added into the mixed solution, and the ultrasonic treatment was continued for 60 min;

[0086] The yellow powder obtained after the reaction was collected by filtration with a 0.22 μm nylon membrane, and sequentially washed with acetone and methanol, then Soxhlet extracted with tetrahydrofuran, and finally dried under vacuum to obtain the chiral two-dimensional covalent organic framework material L-alanine-COF DMTA+TAPB product.

[0087] Comparative Example 2

[0088] 1. A method for preparing a two-dimensional covalent organic framework material (COF DMTA+TAPB ):

[0089] 2,5-dimethoxybenzene-1,4-dicarboxaldehyde (112.8 mg, 0.58 mmol), 1,3,5-tris(4- aminophenyl)benzene (92.8 mg, 0.39 mmol) were weighed into a 10 ml glass bottle, and 6 mol / L aqueous acetic acid solution (8 ml) was added;

[0090] The mixture was ultrasonically treated using a 6 mm micro-tip probe, and a 650W JY92-IIN intelligent ultrasonic crusher was set to drive the probe to operate in a continuous mode at 20 kHz with a power of 60% for 60 minutes;

[0091] The yellow powder obtained after the reaction was collected by filtration with a 0.22 μm nylon membrane, and sequentially washed with acetone and methanol, then Soxhlet extracted with tetrahydrofuran, and finally dried under vacuum to obtain the two-dimensional covalent organic framework material COF TFP+DAB product.

[0092] The 1-L-alanine-COF DMTA+TAPB , 5-L-alanine-COF DMTA+TAPB and COF DMTA+TAPB prepared in Comparative Example 2 and Examples 3-4 were subjected to physicochemical performance characterization and analysis, and the results are shown in Table 1. Figure 6

[0093] Figure 6 The powder X-ray diffraction patterns of 1-L-alanine-COF DMTA+TAPB , 5-L-alanine-COF DMTA+TAPB and COF DMTA+TAPB are shown, and the diffraction peak around 5° shown in the images belongs to the (110) crystal plane of AA stacking. By comparing the crystallinity of the products of different ratios of chiral inducer, it can be found that when the molar ratio of chiral inducer to organic monomer 1 is 1:1, the product with the best crystallinity is obtained.​

[0094] Example 5

[0095] 1. A method for preparing a chiral two-dimensional covalent organic framework material (60 min-S-MBA-COF TFP+DAB ):

[0096] 2,4,6-triformylphloroglucinol (210 mg, 1 mmol) and S-MBA (119 mg, 1 mmol) were weighed into a 10 ml glass bottle, and 6 mol / L aqueous acetic acid solution (4 ml) was added;

[0097] The mixture was subjected to ultrasonic treatment using a 6 mm micro-tip probe, and a 650W JY92-IIN intelligent ultrasonic crusher was set to drive the probe to operate at 20 kHz in continuous mode at 60% power for 10 minutes;

[0098] p-Phenylenediamine (162 mg, 1.5 mmol) was added to the mixed solution, and ultrasonic treatment was continued for 60 min;

[0099] The yellow powder obtained after the reaction was filtered to collect the solid using a 0.22 μm nylon membrane, and was sequentially washed with acetone and methanol, then subjected to Soxhlet extraction with tetrahydrofuran, and finally dried under vacuum to obtain a chiral two-dimensional covalent organic framework material 60 min-S-MBA-COF TFP+DAB .

[0100] Comparative Example 3

[0101] 1. A method for preparing a chiral two-dimensional covalent organic framework material (5 min-S-MBA-COF TFP+DAB ):

[0102] 2,4,6-triformylphloroglucinol (210 mg, 1 mmol) and S-MBA (119 mg, 1 mmol) were weighed into a 10 ml glass bottle, and 6 mol / L aqueous acetic acid solution (4 ml) was added;

[0103] The mixture was subjected to ultrasonic treatment using a 6 mm micro-tip probe, and a 650W JY92-IIN intelligent ultrasonic crusher was set to drive the probe to operate at 20 kHz in continuous mode at 60% power for 10 minutes;

[0104] p-Phenylenediamine (162 mg, 1.5 mmol) was added to the mixed solution, and ultrasonic treatment was continued for 5 min;

[0105] The yellow powder obtained after the reaction was collected by filtration using a 0.22 pm nylon membrane, washed sequentially with acetone and methanol, then Soxhlet extracted with tetrahydrofuran, and finally dried under vacuum to obtain the chiral two-dimensional covalent organic framework material 5 min-S-MBA-COF TFP+DAB product.

[0106] Comparative Example 4

[0107] 1. A method for preparing a chiral two-dimensional covalent organic framework material (10 min-S-MBA-COF TFP+DAB )

[0108] 2,4,6-triformylphloroglucinol (210 mg, 1 mmol) and S-MBA (119 mg, 1 mmol) were weighed into a 10 ml glass bottle, and 6 mol / L aqueous acetic acid solution (4 ml) was added;

[0109] The mixture was subjected to ultrasonic treatment using a 6 mm micro-tip probe, and a 650W JY92-IIN intelligent ultrasonic crusher was set to drive the probe to operate at 20 kHz in continuous mode at 60% power for 10 minutes;

[0110] p-phenylenediamine (162 mg, 1.5 mmol) was added to the mixed solution, and ultrasonic treatment was continued for 10 min;

[0111] The yellow powder obtained after the reaction was collected by filtration using a 0.22 pm nylon membrane, washed sequentially with acetone and methanol, then Soxhlet extracted with tetrahydrofuran, and finally dried under vacuum to obtain the chiral two-dimensional covalent organic framework material 10 min-S-MBA-COF TFP+DAB product.

[0112] Comparative Example 5

[0113] 1. A method for preparing a chiral two-dimensional covalent organic framework material (30 min-S-MBA-COF TFP+DAB )

[0114] 2,4,6-triformylphloroglucinol (210 mg, 1 mmol) and S-MBA (119 mg, 1 mmol) were weighed into a 10 ml glass bottle, and 6 mol / L aqueous acetic acid solution (4 ml) was added;

[0115] The mixture was subjected to ultrasonic treatment using a 6 mm micro-tip probe, and a 650W JY92-IIN intelligent ultrasonic crusher was set to drive the probe to operate at 20 kHz in continuous mode at 60% power for 10 minutes;

[0116] p-phenylenediamine (162 mg, 1.5 mmol) was added into the mixed solution, and the ultrasonic treatment was continued for 30 min;

[0117] The yellow powder obtained after the reaction was collected by filtration with a 0.22 μm nylon membrane, and then washed with acetone and methanol successively, followed by Soxhlet extraction with tetrahydrofuran, and finally dried under vacuum to obtain the chiral two-dimensional covalent organic framework material 30 min-S-MBA-COF TFP+DAB Product.

[0118] The 5 min-S-MBA-COF TFP+DAB , 10 min-S-MBA-COF TFP+DAB , 30 min-S-MBA-COF TFP+DAB , and 60 min-S-MBA-COF TFP+DAB prepared according to Example 1-2 and Comparative Example 1 were subjected to physicochemical performance characterization and analysis, and the results are shown in Figures 7-8 .

[0119] Figure 7 The powder X-ray diffraction patterns of the 5 min-S-MBA-COF TFP+DAB , 10 min-S-MBA-COF TFP+DAB , 30 min-S-MBA-COF TFP+DAB , and 60 min-S-MBA-COF TFP+DAB are shown in the images. The diffraction peak around 5° shown in the images is attributed to the (110) crystal plane of AA stacking. By comparing the crystallinity of the products obtained at different reaction times, it can be found that the product obtained at 60 min has the optimal crystallinity.

[0120] Figure 8 The Fourier transform infrared spectrograms of the 5 min-S-MBA-COF TFP+DAB , 10 min-S-MBA-COF TFP+DAB , 30 min-S-MBA-COF TFP+DAB , and 60 min-S-MBA-COF TFP+DAB are shown. It can be found that the peak value at 1513 cm -1 indicates that a large amount of p-phenylenediamine precursor remains in the product.

[0121] In summary, based on the chiral auxiliary induction method, the covalent organic framework (COF) material with structural chirality is successfully constructed by temporarily introducing a chiral auxiliary during the synthesis process. Unlike the traditional method of achieving chirality function by directly using chiral precursors or post-modification, the chiral auxiliary in this method only exists as an induction factor during the reaction process and does not embed in the final framework structure. This unique induction strategy not only overcomes the problem of uneven distribution of chirality or decline of framework stability caused by embedding chiral molecules in the framework, but also significantly improves the transmission efficiency of chirality information.

[0122] In the traditional method, the use of chiral precursors may be limited by the availability and cost of raw materials; the post-modification method can expand the chirality function of existing materials, but often requires additional steps, which may affect the crystallinity and stability of COF. The chiral auxiliary induction method provides a green and cost-effective solution for constructing chiral COF with high crystallinity and high purity, with its low cost, simplified operation process and high induction efficiency.

[0123] The present application focuses on the construction of structural chirality, which is significantly different from the traditional method of directly imparting chirality function by introducing chiral molecules. Through the induction of chiral auxiliaries, non-chiral precursors can be connected by covalent bonds to form regular and stable chiral framework materials without the need to retain chiral molecules in the final material.

[0124] This method not only enhances the application potential of chiral COF in the fields of chiral separation and catalysis, but also exhibits the advantages of green synthesis, low energy consumption and high efficiency in the synthesis process, providing a new idea for the further development of chiral materials.

[0125] It should be noted that the above examples are only used to illustrate the technical solutions of the present application and are not limiting. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the spirit and scope of the present application, which should be included in the scope of the present application.

Claims

1. A method for preparing a chiral aldehyde-amine condensation covalent organic framework material, characterized in that: include, Introducing chirality: Organic monomer 1 and chiral inducer were dissolved in an aqueous acetic acid solution and subjected to ultrasonic treatment to obtain a mixture; Introduce a second organic monomer and extend the ultrasonic treatment: Add organic monomer 2 to the mixture and perform ultrasonic treatment for 60-120 minutes; Product separation and purification: After ultrasonic treatment, the reaction mixture was separated by vacuum filtration; Wherein, organic monomer 1 includes one or more of triformylphloroglucinol and 2,5-dimethoxybenzene-1,4-dicarboxaldehyde; organic monomer 2 includes one or more of 1,3,5-tris(4-aminophenyl)benzene and p-phenylenediamine; The concentration of the acetic acid aqueous solution is 6 ~ 12 mol / L; The chiral inducer is one or more of (R)-(+)-α-methylbenzylamine, (S)-(+)-α-methylbenzylamine, (R)-(+)-1-(1-naphthyl)ethylamine, (S)-(+)-1-(1-naphthyl)ethylamine, L-alanine, and D-alanine.

2. The method for preparing the chiral aldehyde-amine condensation covalent organic framework material according to claim 1, characterized in that: The diameter of the ultrasonic probe used for introducing chiral ultrasonic treatment is 2 to 10 mm.

3. The method for preparing the chiral aldehyde-amine condensation covalent organic framework material according to claim 1, characterized in that: The molar ratio of the organic monomer 1 to the chiral inducer is 1:1 to 5.

4. The method for preparing the chiral aldehyde-amine condensation covalent organic framework material according to claim 1, characterized in that: The ratio of aldehyde groups to amino groups used in the reaction in the organic monomer is 1:

1.

5. The method for preparing the chiral aldehyde-amine condensation covalent organic framework material according to claim 1, characterized in that: The diameter of the ultrasonic probe used for introducing chirality and ultrasonic processing is 6 mm.

6. The method for preparing the chiral aldehyde-amine condensation covalent organic framework material according to claim 1, characterized in that: In the process of introducing chirality, the ultrasonic treatment is carried out at 30-70% power for 10-30 minutes.

7. The method for preparing the chiral aldehyde-amine condensation covalent organic framework material as described in claim 1, characterized in that: During the extended ultrasonic treatment, the ultrasonic frequency is maintained at 40 kHz and the power is 30-70%.

8. The chiral aldehyde-amine condensation covalent organic framework material prepared by any of the preparation methods described in claims 1 to 7.

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