A donor-acceptor type covalent organic framework material, its preparation method and application

Abstract

This invention relates to porous organic polymer materials, specifically to a donor-acceptor type covalent organic framework material, its preparation method, and its application in the photocatalytic coupling of benzylamine to imine. The structural formula of the donor-acceptor type covalent organic framework material is as follows: The donor-acceptor type covalent organic framework material TPH-BTz-TDA-COF synthesized in this invention exhibits high crystallinity, large porosity, and good chemical and thermal stability. It demonstrates excellent catalytic performance in the photocatalytic coupling of benzylamine to imine.

Description

Technical Field

[0001] This invention relates to porous organic polymer materials, specifically to a donor-acceptor type covalent organic framework material, its preparation method, and its application in the photocatalytic coupling of benzylamine to generate imine. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] Imines and their derivatives are important intermediates in the synthesis of pharmaceuticals, dyes, and fine chemicals. Under light irradiation, the photocatalytic oxidative coupling of benzylamine with O2 offers advantages in terms of high atom economy and environmental friendliness. In recent years, various photocatalysts have been developed to achieve this reaction. Although they exhibit high photocatalytic activity, they also suffer from some problems, such as poor cycle stability and difficulty in catalyst recovery. Therefore, developing efficient and reusable photocatalysts for imine synthesis remains a highly valuable task.

[0004] Covalent organic frameworks (COFs) are porous organic crystalline polymers linked by covalent bonds. Due to their numerous advantages over other traditional porous materials, such as robustness, ease of modification, and functionalization, COFs show great promise for applications in adsorption and separation, heterogeneous catalysis, and energy. Complementary donor-acceptor pairs (DAs) can be integrated into two-dimensional COF frameworks, where intralayer charge transfer effects between donor and acceptor units can promote charge separation and electron transfer, thereby improving photocatalytic efficiency. These properties make COFs a promising platform for efficient and recyclable photocatalysts. Summary of the Invention

[0005] To overcome the above problems, this invention provides a donor-acceptor type covalent organic framework material, its preparation method, and its application in the photocatalytic coupling of benzylamine to generate imine.

[0006] To achieve the above technical objectives, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a donor-acceptor covalent organic framework material TPH-BTz-TDA-COF, the structural formula of which is shown in formula (I):

[0008]

[0009] A second aspect of the present invention provides a method for preparing the above-mentioned donor-acceptor type covalent organic framework material TPH-BTz-TDA-COF, comprising the following steps:

[0010] Ligands 5,10,15,20-tetra(4-aminophenyl)-21H,23H-porphyrin (TPH) and ligand L were dissolved in organic solvents respectively. Acetic acid solution was added dropwise, and the mixture was mixed evenly. The mixed solution was placed in a liquid nitrogen bath and frozen-thawed and degassed three times. After being sealed under vacuum, a solvothermal reaction was carried out to obtain the donor-acceptor type covalent organic framework material TPH-BTz-TDA-COF.

[0011]

[0012] A third aspect of the present invention provides the application of the above-mentioned donor-acceptor type covalent organic framework material TPH-BTz-TDA-COF as a photocatalyst.

[0013] The beneficial effects of this invention are as follows:

[0014] (1) The donor-acceptor type covalent organic framework material TPH-BTz-TDA-COF synthesized in this invention has high crystallinity, large porosity, and good chemical and thermal stability. It exhibits excellent catalytic performance in the photocatalytic coupling of benzylamine to imine. Attached Figure Description

[0015] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0016] Figure 1 The 1H NMR spectrum of compound 1 synthesized in Example 1;

[0017] Figure 2 The carbon NMR spectrum of compound 1 synthesized in Example 1;

[0018] Figure 3 The 1H NMR spectrum of ligand L synthesized in Example 1;

[0019] Figure 4 The images are SEM and TEM images of the donor-acceptor covalent organic framework material TPH-BTz-TDA-COF synthesized in Example 2, where a is SEM and b is TEM.

[0020] Figure 5 The image shows the XRD pattern of the donor-acceptor covalent organic framework material TPH-BTz-TDA-COF synthesized in Example 2.

[0021] Figure 6The infrared spectrum of the donor-acceptor covalent organic framework material TPH-BTz-TDA-COF synthesized in Example 2;

[0022] Figure 7 The UV spectrum of the donor-acceptor covalent organic framework material TPH-BTz-TDA-COF synthesized in Example 2;

[0023] Figure 8 Thermogravimetric spectrum of TPH-BTz-TDA-COF, the donor-acceptor covalent organic framework material synthesized in Example 2;

[0024] Figure 9 The images show XRD patterns of the donor-acceptor covalent organic framework material TPH-BTz-TDA-COF synthesized in Example 2 after immersion in different solvents.

[0025] Figure 10 EPR image of the donor-acceptor covalent organic framework material TPH-BTz-TDA-COF synthesized in Example 2;

[0026] Figure 11 The image shows the PXRD pattern of TPH-BTz-TDA-COF after 5 cycles of benzylamine coupling in Experiment Example 1. Detailed Implementation

[0027] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0028] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0029] A first typical embodiment of the present invention provides a donor-acceptor covalent organic framework material TPH-BTz-TDA-COF, the structural formula of which is shown in formula (Ⅰ):

[0030]

[0031] A second typical embodiment of the present invention provides a method for preparing the above-mentioned donor-acceptor type covalent organic framework material TPH-BTz-TDA-COF, comprising the following steps:

[0032] Ligands 5,10,15,20-tetra(4-aminophenyl)-21H,23H-porphyrin (TPH) and ligand L were dissolved in organic solvents respectively. Acetic acid solution was added dropwise, and the mixture was mixed evenly. The mixed solution was placed in a liquid nitrogen bath and frozen-thawed and degassed three times. After being sealed under vacuum, a solvothermal reaction was carried out to obtain the donor-acceptor type covalent organic framework material.

[0033]

[0034] In one or more embodiments, the method for preparing the ligand L includes:

[0035] (1) In an inert atmosphere, 1,3,5-tribromobenzene, 4-formylphenylboronic acid and potassium carbonate were added to a tetrahydrofuran solution, followed by the addition of a catalyst tetra(triphenylphosphine)palladium. The mixture was heated under reflux. After the reaction was completed, the reaction solution was cooled to room temperature, extracted with dichloromethane, and the dichloromethane was rotary evaporated to obtain compound 1 after purification.

[0036] (2) In an inert atmosphere, compound 1, compound 2 and potassium carbonate were added to a toluene solution, followed by the addition of the catalyst tetra(triphenylphosphine)palladium. The mixture was heated under reflux. After the reaction was completed, the reaction solution was cooled to room temperature, and a methanol solution was added to the reaction solution to obtain a solid. The solid was filtered, washed, and dried to obtain ligand L.

[0037]

[0038] Preferably, in step (1), the molar ratio of 1,3,5-tribromobenzene to 4-formylphenylboronic acid is 1:2 to 2.3, and more preferably 1:2.16.

[0039] Preferably, in step (1), the molar ratio of 4-formylphenylboronic acid to potassium carbonate is 1:2.5 to 3.0, more preferably 1:2.77.

[0040] Preferably, in step (1), the molar ratio of 1,3,5-tribromobenzene to the catalyst tetra(triphenylphosphine)palladium is 1.9 to 2.1:1, more preferably 2:1.

[0041] Preferably, in step (1), the tetrahydrofuran solution is a mixed solution of tetrahydrofuran and water, and the volume ratio of tetrahydrofuran to water is 24 to 26:1, preferably 25:1.

[0042] Preferably, in step (1), the temperature of the reflux reaction is 75-85°C, preferably 80°C, and the reaction time is 70-75h, preferably 72h.

[0043] Preferably, in step (1), the purification method is column chromatography, using a mixture of dichloromethane and petroleum ether as the eluent.

[0044] Preferably, in step (2), the molar ratio of compound 1, compound 2, potassium carbonate, and catalyst tetra(triphenylphosphine)palladium is 3-3.5:1.4-1.6:9-10:0.1-0.15, and more preferably 3.29:1.55:9.42:0.12.

[0045] Preferably, in step (2), the toluene solution is an aqueous solution of toluene, wherein the volume ratio of toluene to water is 50:1 to 2, preferably 50:1.5.

[0046] Preferably, in step (2), the temperature of the reflux reaction is 100-120°C, more preferably 110°C, and the reaction time is 70-75h, more preferably 72h.

[0047] Preferably, in step (2), the methanol solution is an aqueous solution of methanol, and the volume ratio of methanol to water is 4 to 6:1, preferably 5:1.

[0048] Preferably, in step (2), the washing method is to wash with deionized water, hydrochloric acid solution, deionized water, ethanol and dichloromethane in sequence.

[0049] In one or more embodiments, the molar ratio of TPH to ligand L is 0.8 to 1.2:1, preferably 1:1.

[0050] In one or more embodiments, the organic solvent is a mixed solvent of o-dichlorobenzene and n-butanol, wherein the volume ratio of o-dichlorobenzene to n-butanol is 0.8 to 1.2:1, preferably 1:1.

[0051] In one or more embodiments, the concentration of TPH in the organic solvent is 0.008 to 0.012 mol / L, preferably 0.01 mol / L.

[0052] In one or more embodiments, the temperature of the solvothermal reaction is 140–160°C, preferably 150°C, and the reaction time is 6–8 days, preferably 7 days.

[0053] A third typical embodiment of the present invention provides the application of the above-mentioned donor-acceptor type covalent organic framework material TPH-BTz-TDA-COF as a photocatalyst.

[0054] In one or more embodiments, the application includes catalyzing the coupling of benzylamine to imine under light irradiation.

[0055] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments.

[0056] Example 1

[0057] Preparation of ligand L: Under an inert atmosphere, 1,3,5-tribromobenzene (4.56 g, 14.5 mmol), 4-formylphenylboronic acid (4.70 g, 31.4 mmol), and potassium carbonate (12.0 g, 86.9 mmol) were added to a tetrahydrofuran solution (250 mL tetrahydrofuran added to 10 mL water), followed by the addition of the catalyst tetra(triphenylphosphine)palladium (838 mg, 0.720 mmol). The reaction mixture was heated to reflux at 0°C for 72 h. After the reaction was completed, the reaction solution was cooled to room temperature and extracted with dichloromethane (100 mL × 3). The organic phases were combined and dried over anhydrous sodium sulfate. Dichloromethane was rotary evaporated, and the mixture was purified by column chromatography using a mixture of dichloromethane and petroleum ether as eluent (2:1 volume ratio) to give compound 1 (1.80 g, yield 34%). The 1H NMR spectrum of compound 1 is shown below. Figure 1 As shown, the carbon NMR spectrum is as follows: Figure 2 As shown.

[0058] (2) Under an inert atmosphere, compound 1 (1.20 g, 3.29 mmol), compound 2 (600 mg, 1.55 mmol), and potassium carbonate (1.30 g, 9.42 mmol) were added to a toluene solution (1.5 mL of water in 50 mL of toluene), followed by the addition of a catalyst, tetrakis(triphenylphosphine)palladium (143 mg, 0.120 mmol). The mixture was heated to 110 °C and refluxed for 72 h. After the reaction was complete, the reaction solution was cooled to room temperature, and a methanol solution (50 mL of methanol in 250 mL of water) was added. The mixture was stirred for 15 min to obtain a solid. After filtration, the solid was washed successively with deionized water (60 mL), hydrochloric acid solution (1 M, 60 mL), deionized water (60 mL), ethanol (60 mL), and dichloromethane (30 mL). The solid was dried to obtain ligand L (874 mg, yield 80%). The 1H NMR spectrum of ligand L is shown below. Figure 3 As shown.

[0059] The synthesis process of ligand L is as follows:

[0060]

[0061] Example 2

[0062] Preparation of donor-acceptor covalent organic framework material TPH-BTz-TDA-COF:

[0063] Ligand TPH (13.5 mg, 0.02 mmol) and ligand L (14.1 mg, 0.02 mmol) were added to a 10 mL heat-resistant thick-walled glass tube, along with 1 mL of o-dichlorobenzene and 1 mL of n-butanol. The mixture was subjected to ultrasonic treatment in a water bath to ensure thorough mixing, resulting in a deep purple suspension. Acetic acid aqueous solution (6 M, 0.2 mL) was slowly added dropwise, followed by another brief ultrasonic treatment. The mixed solution was then placed in a liquid nitrogen bath for freezing-thawing and degassing three times. After sealing under vacuum, the mixture was solvothermal reacted at 150 °C for 7 days. After the reaction, the precipitate in the glass tube was collected by filtration and thoroughly washed with anhydrous tetrahydrofuran and acetone until the filtrate was colorless. The resulting solid powder was placed in a Soxhlet extractor and further washed with tetrahydrofuran and dichloromethane, respectively. The powder was then dried overnight in a vacuum drying oven at 90 °C to obtain a purple-black donor-acceptor covalent organic framework material, TPH-BTz-TDA-COF (47.25 mg, yield 88%).

[0064] The donor-acceptor covalent organic framework material TPH-BTz-TDA-COF obtained in this embodiment was characterized.

[0065] Figure 4 SEM and TEM images of the donor-acceptor covalent organic framework material TPH-BTz-TDA-COF show that TPH-BTz-TDA-COF is in the form of uniform cubes.

[0066] Figure 5 XRD images of the donor-acceptor covalent organic framework material TPH-BTz-TDA-COF; from Figure 5 As can be seen, this covalent organic framework material has very good crystallinity.

[0067] Figure 6 Infrared spectrum of donor-acceptor covalent organic framework material TPH-BTz-TDA-COF; from Figure 6 As can be seen from this, 3338cm -1 The vibrational peak at 1695 cm⁻¹ belongs to the amino group. -1 The vibrational peaks belonging to the aldehyde group have all disappeared in TPH-BTz-TDA-COF, and the peak at 1626 cm⁻¹ in TPH-BTz-TDA-COF is also absent. -1 A vibrational peak belonging to an imine bond appeared at that point.

[0068] Figure 7 The UV spectrum of the donor-acceptor covalent organic framework material TPH-BTz-TDA-COF; from Figure 7As can be seen, the light absorption of TPH-BTz-TDA-COF combines the characteristics of both ligands, exhibiting both a wider absorption range than ligand L and a redshift due to the influence of the porphyrin ligand.

[0069] Figure 8 Thermogravimetric spectra of donor-acceptor covalent organic framework material TPH-BTz-TDA-COF, from Figure 8 As can be seen, TPH-BTz-TDA-COF begins to lose weight at around 550℃, which means that the structure of TPH-BTz-TDA-COF only begins to collapse at 550℃, indicating that TPH-BTz-TDA-COF has good thermal stability.

[0070] Figure 9 The donor-acceptor type covalent organic framework material TPH-BTz-TDA-COF was stirred in ethanol, tetrahydrofuran, and dichloromethane for 24 h, respectively. XRD images were obtained after filtration and drying. Figure 9 As can be seen, TPH-BTz-TDA-COF still exhibits very good crystallinity after being soaked in different solvents, which also indicates that TPH-BTz-TDA-COF has very good stability.

[0071] Figure 10 EPR images of the donor-acceptor covalent organic framework material TPH-BTz-TDA-COF, from Figure 10 As can be seen, TPH-BTz-TDA-COF can generate superoxide anions under light conditions, and superoxide anions provide the basis for the reaction of catalyzing the coupling of benzylamine to imine.

[0072] Experimental Example 1

[0073] The donor-acceptor covalent organic framework material TPH-BTz-TDA-COF prepared in Example 2 was used to catalyze the coupling of benzylamine to imine.

[0074] (1) 0.2 mmol of benzylamine and 5 mg of TPH-BTz-TDA-COF were added to a 10 mL standard reaction glass tube, along with 2 mL of CHCl3 solvent. The glass tube was sealed with a diaphragm stopper, and the mixture inside was bubbled with oxygen for 20 minutes. An oxygen balloon was then inserted to maintain stable pressure during the reaction. The glass tube was placed under a green LED light source (520 nm) and irradiated for 4 hours with stirring. After the reaction, the product (E)-N-phenylmethylene-1-phenylmethylamine was obtained with a yield of 99%, demonstrating that TPH-BTz-TDA-COF can photocatalyze the coupling of benzylamine to imine. After the reaction, the solution and TPH-BTz-TDA-COF were separated by centrifugation. TPH-BTz-TDA-COF was washed and dried for use in the next cycle experiment. The reaction process is as follows:

[0075]

[0076] (2) The oxidation of benzylamine to (E)-N-phenylmethylene-1-phenylmethylamine was selected as the template reaction. By optimizing the amount of TPH-BTz-TDA-COF, solvent type, and reaction time, the optimal conditions for the photocatalytic coupling of benzylamine with TPH-BTz-TDA-COF were determined. The screening experiments for the photocatalytic coupling of benzylamine with TPH-BTz-TDA-COF are shown in Table 1.

[0077] Table 1. Optimization of photocatalytic benzylamine coupling conditions using TPH-BTz-TDA-COF

[0078]

[0079]

[0080] As shown in Table 1, changing the solvent conditions to acetonitrile, methanol, dichloromethane, and acetone all resulted in varying degrees of decrease in the yield of (E)-N-benzylmethyl-1-phenylmethylamine, at 51%, 29%, 90%, and 0%, respectively. However, the best yield was achieved when CHCl3 was used as the solvent, with a yield as high as 99%. The amount of TPH-BTz-TDA-COF also affected the product yield. Decreasing the amount of TPH-BTz-TDA-COF slightly reduced the yield of (E)-N-benzylmethyl-1-phenylmethylamine, while increasing the catalyst amount did not result in a higher yield. Therefore, the optimal amount of TPH-BTz-TDA-COF was determined to be 5 mg. The product yield decreased when the reaction gas was air, while almost no product was detected when the reaction gas was an inert gas, N2, indicating that an oxygen environment is necessary for this oxidation reaction. In summary, the optimal reaction conditions for the photocatalytic coupling of TPH-BTz-TDA-COF with benzylamine were determined to be: 0.1 mmol benzylamine, 5 mg TPH-BTz-TDA-COF, oxygen environment, and 2 mL CHCl3 solvent.

[0081] (3) The recyclability of TPH-BTz-TDA-COF was verified by a cyclic experiment. TPH-BTz-TDA-COF was subjected to 5 benzylamine coupling cycles, and the PXRD of the powder after the reaction was measured. The results are as follows: Figure 11 As stated, from Figure 11 The results show that the main peak of TPH-BTz-TDA-COF and other smaller peaks remain stable, indicating that the reacted TPH-BTz-TDA-COF still possesses high crystallinity. The yields of the five cycles were 99%, 97%, 93%, 95%, and 98%, respectively, demonstrating that the COF still exhibits good catalytic activity after five cycles.

[0082] (4) Based on the determination of the optimal reaction conditions, the universality of the benzylamine photocatalytic oxidative coupling experiment was explored through substrate expansion experiments.

[0083]

[0084] 0.2 mmol of 4-methoxybenzylamine and 5 mg of TPH-BTz-TDA-COF were added to a 10 mL standard reaction glass tube, along with 2 mL of CHCl3 solvent. The tube was sealed with a diaphragm stopper, and the mixture was bubbled with oxygen for 20 minutes. An oxygen balloon was then inserted to maintain stable pressure during the reaction. The glass tube was placed under a green LED light source (520 nm) and irradiated for 4 hours with stirring. After the reaction was complete, the product N-(4-methoxybenzyl)-1-(4-methoxyphenyl)benzylimine was obtained in 95% yield.

[0085] 0.2 mmol of 4-chlorobenzylamine and 5 mg of TPH-BTz-TDA-COF were added to a 10 mL standard reaction glass tube, along with 2 mL of CHCl3 solvent. The tube was sealed with a diaphragm stopper, and the mixture was bubbled with oxygen for 20 minutes. An oxygen balloon was then inserted to maintain stable pressure during the reaction. The glass tube was placed under a green LED light source (520 nm) and irradiated for 4 hours with stirring. After the reaction was complete, the product N-(4-chlorobenzyl)-1-(4-chlorophenyl)benzylimine was obtained in 93% yield.

[0086] 0.2 mmol of 4-bromobenzylamine and 5 mg of TPH-BTz-TDA-COF were added to a 10 mL standard reaction glass tube, along with 2 mL of CHCl3 solvent. The tube was sealed with a diaphragm stopper, and the mixture was bubbled with oxygen for 20 minutes. An oxygen balloon was then inserted to maintain stable pressure during the reaction. The glass tube was placed under a green LED light source (520 nm) and irradiated for 4 hours with stirring. After the reaction was complete, the product N-(4-bromobenzyl)-1-(4-bromophenyl)benzylimine was obtained in 90% yield.

[0087] 0.2 mmol of 4-fluorobenzylamine and 5 mg of TPH-BTz-TDA-COF were added to a 10 mL standard reaction glass tube, along with 2 mL of CHCl3 solvent. The tube was sealed with a diaphragm stopper, and the mixture was bubbled with oxygen for 20 minutes. An oxygen balloon was then inserted to maintain stable pressure during the reaction. The glass tube was placed under a green LED light source (520 nm) for 4 hours with stirring. After the reaction was complete, the product N-(4-fluorobenzyl)-1-(4-fluorophenyl)benzylimine was obtained in 90% yield.

[0088] 0.2 mmol of 4-methylbenzylamine and 5 mg of TPH-BTz-TDA-COF were added to a 10 mL standard reaction glass tube, along with 2 mL of CHCl3 solvent. The tube was sealed with a diaphragm stopper, and the mixture was bubbled with oxygen for 20 minutes. An oxygen balloon was then inserted to maintain stable pressure during the reaction. The glass tube was placed under a green LED light source (520 nm) and irradiated for 4 hours with stirring. After the reaction was complete, the product N-(4-methylbenzyl)-1-(4-methylphenyl)benzylimine was obtained in 97% yield.

[0089] The above description is merely a preferred embodiment of the present invention and is not intended to limit the 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 donor-acceptor type covalent organic framework material TPH-BTz-TDA-COF, characterized in that, The structural formula of the donor-acceptor type covalent organic framework material is shown in formula (Ⅰ): Equation (Ⅰ).

2. The method for preparing the donor-acceptor type covalent organic framework material TPH-BTz-TDA-COF according to claim 1, characterized in that, Includes the following steps: The ligands 5,10,15,20-tetratetra(4-aminophenyl)-21H,23H-porphyrin (TPH) and L were dissolved separately in organic solvents. An acetic acid solution was then added dropwise, and the mixtures were thoroughly mixed. The resulting solution was then placed in a liquid nitrogen bath and frozen. After thawing and degassing three times, the material was sealed under vacuum and subjected to a solvothermal reaction to obtain a donor-acceptor type covalent organic framework material. 。 3. The method for preparing the donor-acceptor type covalent organic framework material TPH-BTz-TDA-COF as described in claim 2, characterized in that, The preparation method of the ligand L includes: (1) In an inert atmosphere, 1,3,5-tribromobenzene, 4-formylphenylboronic acid and potassium carbonate were added to a tetrahydrofuran solution, followed by the addition of the catalyst tetra(triphenylphosphine)palladium. The mixture was heated under reflux. After the reaction was completed, the reaction solution was cooled to room temperature, extracted with dichloromethane, and the dichloromethane was rotary evaporated to obtain compound 1 after purification. (2) In an inert atmosphere, compound 1, compound 2 and potassium carbonate were added to a toluene solution, followed by the addition of the catalyst tetra(triphenylphosphine)palladium. The mixture was heated under reflux. After the reaction was completed, the reaction solution was cooled to room temperature, and a methanol solution was added to the reaction solution to obtain a solid. The solid was filtered, washed, and dried to obtain ligand L. 。 4. The method for preparing the donor-acceptor type covalent organic framework material TPH-BTz-TDA-COF as described in claim 3, characterized in that, In step (1), the molar ratio of 1,3,5-tribromobenzene to 4-formylphenylboronic acid is 1:2~2.3; Alternatively, in step (1), the molar ratio of 4-formylphenylboronic acid to potassium carbonate is 1:2.5~3.0; Alternatively, in step (1), the molar ratio of 1,3,5-tribromobenzene to the catalyst tetra(triphenylphosphine)palladium is 1.9~2.1:1; Alternatively, in step (1), the tetrahydrofuran solution is a mixed solution of tetrahydrofuran and water, with a volume ratio of tetrahydrofuran to water of 24~26:

1.

5. The method for preparing the donor-acceptor type covalent organic framework material TPH-BTz-TDA-COF as described in claim 4, characterized in that, In step (1), the molar ratio of 1,3,5-tribromobenzene to 4-formylphenylboronic acid is 1:2.16; Alternatively, in step (1), the molar ratio of 4-formylphenylboronic acid to potassium carbonate is 1:2.77; Alternatively, in step (1), the molar ratio of 1,3,5-tribromobenzene to the catalyst tetra(triphenylphosphine)palladium is 2:1; Alternatively, in step (1), the volume ratio of tetrahydrofuran to water is 25:

1.

6. The method for preparing the donor-acceptor type covalent organic framework material TPH-BTz-TDA-COF as described in claim 3, characterized in that, In step (1), the temperature of the reflux reaction is 75~85℃ and the reaction time is 70~75 h.

7. The method for preparing the donor-acceptor type covalent organic framework material TPH-BTz-TDA-COF as described in claim 6, characterized in that, In step (1), the temperature of the reflux reaction is 80 °C and the reaction time is 72 h.

8. The method for preparing the donor-acceptor type covalent organic framework material TPH-BTz-TDA-COF as described in claim 3, characterized in that, In step (2), the molar ratio of compound 1, compound 2, potassium carbonate, and catalyst tetra(triphenylphosphine)palladium is 3~3.5:1.4~1.6:9~10:0.1~0.15; Alternatively, in step (2), the toluene solution is an aqueous solution of toluene, wherein the volume ratio of toluene to water is 50:1~2; Alternatively, in step (2), the temperature of the reflux reaction is 100~120 ℃ and the reaction time is 70~75 h.

9. The method for preparing the donor-acceptor type covalent organic framework material TPH-BTz-TDA-COF as described in claim 8, characterized in that, In step (2), the molar ratio of compound 1, compound 2, potassium carbonate, and catalyst tetra(triphenylphosphine)palladium is 3.29:1.55:9.42:0.12; Alternatively, in step (2), the volume ratio of toluene to water is 50:1.5; Alternatively, in step (2), the temperature of the reflux reaction is 110 °C and the reaction time is 72 h.

10. The method for preparing the donor-acceptor type covalent organic framework material TPH-BTz-TDA-COF as described in claim 2, characterized in that, The molar ratio of TPH to ligand L is 0.8~1.2:1; Alternatively, the organic solvent is a mixed solvent of o-dichlorobenzene and n-butanol, with a volume ratio of o-dichlorobenzene to n-butanol of 0.8 to 1.2:

1.

11. The method for preparing the donor-acceptor type covalent organic framework material TPH-BTz-TDA-COF as described in claim 10, characterized in that, The molar ratio of TPH to ligand L is 1:1; Alternatively, the volume ratio of o-dichlorobenzene to n-butanol is 1:

1.

12. The method for preparing the donor-acceptor type covalent organic framework material TPH-BTz-TDA-COF as described in claim 2, characterized in that, The concentration of TPH in organic solvents is 0.008~0.012 mol / L; Alternatively, the temperature of the solvothermal reaction is 140~160 ℃, and the reaction time is 6~8 days.

13. The method for preparing the donor-acceptor type covalent organic framework material TPH-BTz-TDA-COF as described in claim 12, characterized in that, The concentration of TPH in organic solvents is 0.01 mol / L; Alternatively, the solvothermal reaction temperature is 150 °C, and the reaction time is 7 days.

14. The application of the donor-acceptor type covalent organic framework material TPH-BTz-TDA-COF as described in claim 1 as a photocatalyst.

15. The application as described in claim 14, characterized in that, The application includes catalyzing the coupling of benzylamine to imine under light irradiation.

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