An indolocarbazole covalent organic framework material, a preparation method and application thereof

Abstract

The application discloses an indole and carbazole covalent organic framework material and a preparation method and application thereof, the material has a structure as shown in formula I, the preparation method is that aldehyde monomers and indole compounds are dissolved in a solvent, or the indole compounds containing aldehyde groups are dissolved in a solvent alone, an acid catalyst is added, a product is obtained after reaction at room temperature, and then the product is subjected to oxidation, washing and drying to obtain the indole and carbazole covalent organic framework material. The indole and carbazole covalent organic framework material is synthesized by aldehyde monomers and indole compounds at room temperature for the first time, and the problem that the covalent organic framework material synthesis needs high-temperature and high-pressure conditions is solved. The method can construct the indole and carbazole covalent organic framework material containing different and ordered aldehyde monomers through a step-by-step reaction, the reaction condition is mild, and the method is a simple, low-cost and green catalytic synthesis method of the covalent organic framework material.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of covalent organic framework materials (COFs) and their synthesis, and particularly relates to an indolocarbazole covalent organic framework material and a preparation method and application thereof. BACKGROUND

[0002] Since the Yaghi group synthesized the first covalent organic framework material (COF) in 2005, a large number of COF materials have been developed and widely used in gas storage and separation, heterogeneous catalysis, energy storage and conversion, and electronic and semiconductor fields.

[0003] Covalent organic framework materials have the advantages of low density, high thermal stability, periodic structure and permanent void. However, the COF-1 and COF-5 synthesized by Yaghi use a self-condensation connection mode of boric acid, and the B-O bond formed thereby is very sensitive to water and can even be decomposed by water vapor in the air. This limits its application in various fields, so a large number of new connection modes have been developed, such as imine bond, amide bond, hydrazone bond and the like formed by Schiff base reaction of formyl group and amino group, which effectively improves the water stability. There are also connection modes such as triazine ring formed by self-polymerization of cyano group under the catalysis of zinc chloride, benzene ring formed by acetyl under the catalysis of acid, etc. At present, the synthesis methods of covalent organic framework materials include solvothermal method, ionothermal method, mechanical grinding method, microwave irradiation method, interfacial synthesis method, room temperature synthesis method and the like, but most of the covalent organic framework materials are still synthesized by solvothermal method (usually at about 120℃), so it is valuable to develop more methods for synthesizing COF at room temperature.

[0004] At the same time, the above methods are all single-step reactions, and the addition of other monomers in the reaction can only obtain a mixed disordered structure, and cannot orderly connect monomers with different functions to form COF, so it is necessary and valuable to develop a synthesis method capable of connecting different functional monomers at the same time. SUMMARY

[0005] In view of the deficiencies of the prior art, the present application provides an indolocarbazole covalent organic framework material and a preparation method and application thereof, which overcomes the shortcomings of high temperature and pressure required by the traditional solvothermal synthesis of covalent organic framework materials, and is a simple, low-cost and green method for synthesizing covalent organic framework materials.

[0006] The present application is realized by the following technical solutions:

[0007] An indolocarbazole covalent organic framework material, which has a structure as shown in Formula I:

[0008]

[0009] In formula I: R is one or more of hydrogen atom, bromine, chlorine, fluorine, hydroxyl, amino, formyl; R1 is an aldehyde monomer involved in the reaction; n is a natural number greater than or equal to 3.

[0010] A preparation method of an indolocarbazole covalent organic framework material, comprising the following steps:

[0011] Step 1) one or two aldehyde monomers and an indole compound are dissolved in an organic solvent at a molar ratio of 1:0.25-1; or the indole compound containing an aldehyde group is dissolved in an organic solvent alone; and an acid catalyst is added in an amount of 0.01%-5% of the molar amount of the aldehyde monomer, and the reaction is carried out at room temperature for 0.1-72 h to obtain a product; the reaction equation is shown in formula II:

[0012]

[0013] In formula II: R is hydrogen atom, bromine, chlorine, fluorine, hydroxyl, amino or formyl; R1 and R2 are phenyl or indole groups;

[0014] Step 2) the product is oxidized by an oxidizing agent, the solid is separated by centrifugation, and the solid is repeatedly washed with water and ethanol and then vacuum dried to obtain the indolocarbazole covalent organic framework material.

[0015] Preferably, the aldehyde monomer in step 1) is one of 1,3,5-tris(p-formylphenyl)benzene, 1,3,5-tris(4'-formyl[1,1'-biphenyl]-4-yl)benzene, 2,4,6-tris(4-formylphenyl)-1,3,5-triazine, 1,3,6,8-tetra(4-formylphenyl)pyrene and tetraformylphenylporphyrin.

[0016] Preferably, the structure of the indole compound and the indole compound containing an aldehyde group in step 1) is shown in formula III:

[0017]

[0018] In formula III: R is one or more of hydrogen atom, bromine, chlorine, fluorine, hydroxyl, amino, formyl and formylphenyl.

[0019] Preferably, the organic solvent in step 1) is one or more of N,N-dimethylformamide, dimethyl sulfoxide, methanol, dichloromethane and acetonitrile; and the acid catalyst is one or more of hydrochloric acid, hydroiodic acid, hydrobromic acid, hydrofluoric acid, trifluoroacetic acid and sulfuric acid.

[0020] Preferably, the oxidizing agent in step 2) is one or more of oxygen, hydrogen peroxide, elemental iodine and tetrachlorobenzoquinone.

[0021] Application of the above-mentioned indolocarbazole covalent organic framework material in gas adsorption and storage.

[0022] Application of the above-mentioned indolocarbazole covalent organic framework material in loading drugs or catalysts.

[0023] Application of the above-mentioned indolocarbazole covalent organic framework material as electrode material and sensor.

[0024] Application of the above-mentioned indolocarbazole covalent organic framework material as antibacterial material.

[0025] The beneficial effects of the present application are as follows:

[0026] (1) The method of the present application synthesizes an indolocarbazole covalent organic framework material by using an aldehyde monomer and an indole compound for the first time.

[0027] (2) The method of the present application can synthesize an indolocarbazole covalent organic framework material at room temperature, solving the problem of high temperature and high pressure conditions required for the synthesis of covalent organic framework materials.

[0028] (3) The method of the present application can construct an indolocarbazole covalent organic framework material containing different aldehyde monomers through a step-by-step reaction, which can combine different monomers into the same COF in an orderly manner. However, direct mixing of different monomers at one time can only obtain a material with uniform but random arrangement.

[0029] (4) The present application provides a simple and low-cost method for synthesizing a covalent organic framework material, and the yield of the covalent organic framework material prepared by the method is 60% to 90%.

[0030] (5) The covalent organic framework material prepared by the present application has a large specific surface area and has great application potential in gas adsorption and storage.

[0031] (6) The covalent organic framework material prepared by the present application has a regular structure, a large number of secondary amine groups and a modifiable active site, and has great application potential in loading drugs and or loading catalysts.

[0032] (7) The covalent organic framework material prepared by the present application has a completely conjugated skeleton structure, and has great potential as an electrode material and a sensor.

[0033] (8) The covalent organic framework material prepared by the present application has a modifiable secondary amine and has potential antibacterial properties. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 The Fourier infrared spectra of the covalent organic framework material 5a, the intermediate 5a-0 and the raw materials 1a and 2a synthesized in Example 2.

[0035] Figure 2 Scanning electron microscope image of the covalent organic framework material 5a synthesized in Example 2: A is a 10 μm scale, and B is a 5 μm scale;

[0036] Figure 3 Transmission electron microscope image of the covalent organic framework material 5a synthesized in Example 2: A is a 2 μm scale, and B is a 1 μm scale;

[0037] Figure 4 Thermogravimetric analysis graph of the covalent organic framework material 5a synthesized in Example 2;

[0038] Figure 5 Isothermal adsorption curve of the covalent organic framework material 5a synthesized in Example 2;

[0039] Figure 6 Pore size distribution graph of the covalent organic framework material 5a synthesized in Example 2;

[0040] Figure 7 Particle size distribution graph of the covalent organic framework material 5a synthesized in Example 2. DETAILED DESCRIPTION

[0041] The application will be further described below in conjunction with the accompanying drawings and specific examples. The following examples are implemented on the premise of the technical solution of the application, and a detailed implementation process is given, but the protection scope of the application is not limited to the following examples.

[0042] Example 1

[0043] An indolocarbazole covalent organic framework material has a structure as shown in Formula I:

[0044]

[0045] In Formula I, R is one or more of a hydrogen atom, bromine, chlorine, fluorine, a hydroxyl group, an amino group, and a formyl group; R1 is an aldehyde monomer involved in the reaction; and n is a natural number ≥ 3.

[0046] A preparation method of an indolocarbazole covalent organic framework material, and the specific steps are as follows:

[0047] (1) One or two aldehyde monomers and an indole compound are dissolved in an organic solvent at a molar ratio of 1:0.25-1, or the indole compound containing an aldehyde group is dissolved in an organic solvent alone, and an acid catalyst in an amount of 0.01%-5% of the molar amount of the aldehyde monomer is added, and the reaction is carried out at room temperature for 0.1-72 h to obtain a product; the reaction equation is shown in Formula II:

[0048]

[0049] In formula II, R is a hydrogen atom, bromine, chlorine, fluorine, hydroxyl, amino or formyl; R1, R2 are phenyl or indole groups.

[0050] In a preferred embodiment, the aldehyde monomer is one of 1,3,5-tris(p-formylphenyl)benzene, 1,3,5-tris(4'-formyl[1,1'-biphenyl]-4-yl)benzene, 2,4,6-tris(4-formylphenyl)-1,3,5-triazine, 1,3,6,8-tetra(4-formylphenyl)pyrene, tetraformylphenylporphyrin.

[0051] In a preferred embodiment, the indole compound and the aldehyde-containing indole compound have the structure shown in formula III:

[0052]

[0053] In formula III, R is one or more of a hydrogen atom, bromine, chlorine, fluorine, hydroxyl, amino, formyl, formylphenyl.

[0054] In a preferred embodiment, the organic solvent is one or more of N,N-dimethylformamide, dimethyl sulfoxide, methanol, dichloromethane, acetonitrile.

[0055] In a preferred embodiment, the acid catalyst is one or more of hydrochloric acid, hydroiodic acid, hydrobromic acid, hydrofluoric acid, trifluoroacetic acid, sulfuric acid.

[0056] (2) The product obtained in step (1) is oxidized by an oxidizing agent, the solid is separated by centrifugation, and the solid is repeatedly washed with water and ethanol and then vacuum dried to obtain the indolocarbazole covalent organic framework material.

[0057] In a preferred embodiment, the oxidizing agent is one or more of oxygen, hydrogen peroxide, elemental iodine, and tetrachloroquinone.

[0058] Example 2

[0059] The synthesis of the covalent organic framework material using 1,3,5-tris(p-formylphenyl)benzene and indole as precursors has the reaction equation shown in formula IV, and the specific steps are as follows:

[0060]

[0061] (1) 1,3,5-tris(p-formylphenyl)benzene (1a, 390 mg, 1 mmol) is dissolved in 50 mL of dichloromethane, and a solution of indole (2a, 351 mg, 3 mmol) in 5 mL of dichloromethane is added dropwise, and 20 μL of hydrochloric acid is added, and the reaction is carried out at room temperature for 24 h. At this time, the unoxidized intermediate (5a-0) can be obtained by centrifugation.

[0062] (2) Air was introduced again for oxidation, the solid was separated by centrifugation, washed three times with ethanol and water respectively, and dried at 100°C for 12 hours to obtain the target product (5a), with a yield of about 90%.

[0063] like Figure 1 The image shows the Fourier transform infrared (FTIR) spectra of the covalent organic framework material 5a, intermediate 5a-0, and raw materials 1a and 2a synthesized in this embodiment. Specifically, the 744 cm⁻¹ of 2a... -1 δ of the ortho-disubstituted benzene ring C-H The presence of indole in 5a indicates that the structure of indole is retained during the reaction. In 2a, 3401 cm⁻¹ -1 ν at the location N-H The disappearance of the ν group in spectra 5a-0 and 5a indicates that the secondary amine on the indole reacts with the acid. The ν group of the aldehyde group in 1a... C＝O The peak is located at 1680cm -1 The aldehyde group in 1a disappeared in intermediate 5a-0 and final product 5a, indicating that the aldehyde group in 1a was fully involved in the reaction. Intermediate 5a-0 was present at 1668 cm⁻¹. -1 ν appears on the left and right C＝C The peak indicates the presence of the unoxidized intermediate. Furthermore, the disappearance of this peak in the spectrum of product 5a after oxidation confirms that the carbon-carbon double bond was oxidized to a benzene ring structure. Based on the above analysis, Figure 1 The synthesis of covalent organic framework material 5a was confirmed.

[0064] like Figure 2 As shown, the morphology of covalent organic framework material 5a was observed by scanning electron microscopy, proving that the synthesized indolocarbazole covalent organic framework material has a spherical structure.

[0065] like Figure 3 As shown, the covalent organic framework material 5a was observed by transmission electron microscopy, which also proved that the synthesized indolocarbazole covalent organic framework material has a spherical structure and a uniform internal structure.

[0066] like Figure 4 As shown in the thermogravimetric analysis diagram, the prepared covalent organic framework material 5a only decomposes slowly at 350℃ and retains 74.6% of its mass at 800℃, indicating that it has good thermal stability.

[0067] like Figure 5 As shown, by measuring the isothermal adsorption curve of covalent organic framework material 5a, its specific surface area was calculated to be 165 m² using the BET method. 2 / g, its surface area calculated using the Langmuir method is 395m². 2 / g proves that it has a high specific surface area.

[0068] As shown in Figure 6 The pore size distribution of the covalent organic framework material 5a is mainly distributed in 2-10 nm and 20-40 nm, which is respectively the material's own channel and the stacking effect, which proves that it has a controllable mesoporous structure.

[0069] As shown in Figure 7 The scanning electron microscope image is labeled by image processing software, and the particle size distribution of the covalent organic framework material 5a is counted, and the particle size distribution graph is obtained. As can be seen from the graph, the particle size is uniformly distributed at about 3.12 μm, which proves that it has a relatively uniform particle size distribution.

[0070] Example 3

[0071] The synthesis of the covalent organic framework material with 1,3,6,8-tetra(4-formaldehyde phenyl)pyrene and 6-hydroxyindole as precursors, the reaction equation is as shown in formula V, the specific steps are as follows:

[0072]

[0073] (1) 1,3,6,8-tetra(4-formaldehyde phenyl)pyrene (1b, 620 mg, 1 mmol) was dissolved in 50 mL of dimethylformamide, 6-hydroxyindole (2b, 532 mmol, 4 mmol) in 5 mL of dichloromethane was added dropwise, and 10 μL of hydroiodic acid (56%) was added, and the reaction was carried out at room temperature for 72 h.

[0074] (2) 2 mL of hydrogen peroxide solution (8%) was added for oxidation, the solid was separated by centrifugation, and was washed with ethanol and water three times respectively, and was dried at 100°C for 12 h to obtain the target product (5b), the yield was about 85%.

[0075] Example 4

[0076] The synthesis of the covalent organic framework material with tetraaldehyde phenyl porphyrin and 6-bromoindole as precursors, the reaction equation is as shown in formula VI, the specific steps are as follows:

[0077]

[0078] (1) Tetraaldehyde phenyl porphyrin (1c, 726 mg, 1 mmol) was dissolved in 50 mL of acetonitrile, 6-bromoindole (2c, 532 mmol, 4 mmol) in 5 mL of dichloromethane was added dropwise, and 20 μL of trifluoroacetic acid was added, and the reaction was carried out at room temperature for 72 h.

[0079] (2) Air oxidation, the solid was separated by centrifugation, washed with ethanol and water three times respectively, dried at 100℃ for 12h, the target product (5c) was obtained with a yield of about 89%.

[0080] Example 5

[0081] The synthesis of covalent organic framework material with 1,3,5-tris(4'-formyl[1,1'-biphenyl]-4-yl)benzene and 5,6,7-trifluoroindole as precursors, the reaction equation is shown in formula VII, the specific steps are as follows:

[0082]

[0083] (1) 1,3,5-tris(4'-formyl[1,1'-biphenyl]-4-yl)benzene (1d, 618mg, 1mmol) was dissolved in 50mL dimethylformamide, 5,6,7-trifluoroindole (2d, 513mmol, 3mmol) was added dropwise in 5mL dichloromethane, and 10μL of hydroiodic acid was added, and the reaction was carried out at room temperature for 72h.

[0084] (2) Air oxidation, the solid was separated by centrifugation, washed with ethanol and water three times respectively, dried at 100℃ for 12h, the target product (5c) was obtained with a yield of about 89%.

[0085] Example 6

[0086] The synthesis of covalent organic framework material with 1,3,5-tris(4'-formyl[1,1'-biphenyl]-4-yl)benzene and 5,6,7-trifluoroindole as precursors, the reaction equation is shown in formula VII, the specific steps are as follows:

[0087]

[0088] (1) 1,3,5-tris(4'-formyl[1,1'-biphenyl]-4-yl)benzene (1d, 618mg, 1mmol) was dissolved in 50mL dimethylformamide, 5,6,7-trifluoroindole (2d, 513mmol, 3mmol) was added dropwise in 5mL dichloromethane, and 10μL of hydroiodic acid was added, and the reaction was carried out at room temperature for 72h. ’ Substitution reaction, the reaction solution containing intermediate compound (3a) was obtained.

[0089] (2) 2,4,6-tris(4-formylphenyl)-1,3,5-triazine (1e, 197 mg, 0.5 mmol) was dissolved in 5 mL of dimethylformamide and added to the above reaction solution, and the reaction was carried out at room temperature for 48 h. The formyl group contained in the newly added compound will further react with intermediate 3a to form a cyclic structure.

[0090] (3) Air was introduced for oxidation, the solid was separated by centrifugation, washed with ethanol and water three times respectively, and dried at 100°C for 12 h to obtain the target product (5e) with a yield of about 81%.

[0091] Example 7

[0092] The covalent organic framework material was directly synthesized with 6-formylindole as a precursor, and the reaction equation is shown in formula IX, and the specific steps are as follows:

[0093]

[0094] (1) 6-formylindole (1f, 435 mg, 3 mmol) was dissolved in 50 mL of dichloromethane, and 10 μL of hydroiodic acid was added, and the reaction was carried out at room temperature for 48 h.

[0095] (2) Air was introduced for oxidation, the solid was separated by centrifugation, washed with ethanol and water three times respectively, and dried at 100°C for 12 h to obtain the target product (5f) with a yield of about 88%.

[0096] The above only describes the preferred embodiments of the present application, but the protection scope of the present application is not limited to this. Any changes, simplifications and modifications made in the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. An indolocarbazole-based covalent organic framework material, characterized in that, The material has a structure as shown in Formula I: Formula I; In Formula I, R is one or more of hydrogen atom, bromine, chlorine, fluorine, hydroxyl, amino, formyl; R1 is derived from an aldehyde monomer, which is one of 1,3,5-tris(p-formylphenyl)benzene, 1,3,5-tris(4'-formyl[1,1'-biphenyl]-4-yl)benzene, 2,4,6-tris(4-formylphenyl)-1,3,5-triazine, 1,3,6,8-tetra(4-formylphenyl)pyrene, tetraformylphenylporphyrin; and n is a natural number ≥ 3.

2. The method for preparing an indole-carbazole covalent organic framework material according to claim 1, characterized in that, The method comprises the following steps: Step 1) one or two aldehyde monomers and indole compounds are dissolved in an organic solvent at a molar ratio of 1:0.25-1; or the indole compound containing aldehyde groups is dissolved in an organic solvent alone; and an acid catalyst is added in an amount of 0.01%-5% of the molar amount of the aldehyde monomer, and the reaction is carried out at room temperature for 0.1-72 h to obtain a product; Step 2) the product is oxidized by an oxidizing agent, the solid is separated by centrifugation, and the solid is repeatedly washed with water and ethanol and then vacuum dried to obtain the indole-carbazole covalent organic framework material.

3. The method for preparing an indole-carbazole covalent organic framework material according to claim 2, characterized in that, In step 1), the aldehyde monomer is one of 1,3,5-tris(p-formylphenyl)benzene, 1,3,5-tris(4'-formyl[1,1'-biphenyl]-4-yl)benzene, 2,4,6-tris(4-formylphenyl)-1,3,5-triazine, 1,3,6,8-tetra(4-formylphenyl)pyrene, tetraformylphenylporphyrin.

4. The method for preparing an indole-carbazole covalent organic framework material according to claim 2, characterized in that, In step 1), the indole compound and the indole compound containing aldehyde groups have a structure as shown in Formula III: Formula III; In Formula III, R is one or more of hydrogen atom, bromine, chlorine, fluorine, hydroxyl, amino, formyl, formylphenyl.

5. The method for preparing an indole-carbazole covalent organic framework material according to claim 2, characterized in that, In step 1), the organic solvent is one or more of N,N-dimethylformamide, dimethyl sulfoxide, methanol, dichloromethane, acetonitrile; and the acid catalyst is one or more of hydrochloric acid, hydroiodic acid, hydrobromic acid, hydrofluoric acid, trifluoroacetic acid, sulfuric acid.

6. The method for preparing an indole-carbazole covalent organic framework material according to claim 2, characterized in that, In step 2), the oxidizing agent is one or more of oxygen, hydrogen peroxide, elemental iodine, and tetrachlorobenzoquinone.

7. The indole-carbazole covalent organic framework material of claim 1, or the indole-carbazole covalent organic framework material prepared by the method of any one of claims 2-6, is applied in gas adsorption and storage.

8. The indole-carbazole covalent organic framework material of claim 1, or the indole-carbazole covalent organic framework material prepared by the method of any one of claims 2-6, is applied in loading of drugs or catalysts.

9. The indole-carbazole covalent organic framework material of claim 1, or the indole-carbazole covalent organic framework material prepared by the method of any one of claims 2-6, is applied as an electrode material and a sensor.

10. The indole-carbazole covalent organic framework material of claim 1, or the indole-carbazole covalent organic framework material prepared by the method of any one of claims 2-6, is applied as an antibacterial material.

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