A clover-shaped covalent organic framework material and a preparation method thereof

Abstract

This invention discloses a method for preparing a clover-shaped covalent organic framework material, relating to the field of organic synthetic functional materials technology. Specifically, the method includes: S1: adding pyromellitic tricarboxyhydrazide and 2,6-dicarboxy-4-methylphenol to a glass bottle, followed by the addition of an organic solution to obtain mixture A; S2: dispersing mixture A obtained in S1 evenly, then adding a catalyst for catalysis, and finally sealing the glass bottle with a cap to obtain mixture B. This invention utilizes the reaction of pyromellitic tricarboxyhydrazide and 2,6-dicarboxy-4-methylphenol to prepare a novel clover-shaped covalent organic framework material. This clover-shaped covalent organic framework material is applied to the detection of Fe in water. 3+ This allows the material to be used as a fluorescent probe to identify Fe. 3+ This leads to fluorescence quenching, exhibiting sensitive fluorescence response behavior, thus enabling effective detection of Fe in wastewater. 3+ It has good effects when used.

Description

Technical Field

[0001] This invention relates to the field of organic synthetic functional materials technology, specifically to a clover-shaped covalent organic framework material and its preparation method. Background Technology

[0002] Covalent organic frameworks (COFs) are a novel class of porous crystalline materials that have attracted widespread attention due to their potential applications in gas adsorption and separation, heterogeneous catalysis, energy storage, drug delivery, and fluorescence recognition. Although two-dimensional COF materials have seen rapid development, their structures are predominantly hexagonal and quadrilateral, with other structural types being relatively rare. Compared to polymer materials, COFs possess a regular pore structure; compared to metal-organic frameworks, COFs exhibit better stability.

[0003] The indiscriminate discharge of industrial wastewater, agricultural wastewater, and domestic sewage is a major cause of water pollution. Polluted water contains large amounts of metal ions, which seriously affect human health. In the natural environment, these metal ions are difficult to degrade and accumulate in the human body through bioaccumulation, leading to an imbalance of metal levels in the body. For example, Fe in the human body... 3+ Excessive levels of these metal ions can lead to diseases such as hemoglobin deposition and diabetes. Therefore, how to quickly and efficiently detect metal ions in water pollution has always been a hot research topic for scientists. Summary of the Invention

[0004] The purpose of this invention is to provide a clover-shaped covalent organic framework material and its preparation method to solve the problems mentioned in the background art, which can be applied to the field of metal ion recognition.

[0005] To achieve the above-mentioned objectives, the present invention adopts the following technical solution: This invention provides a method for preparing a clover-shaped covalent organic framework material, comprising the following steps: S1: Add pyromellitic trihydrazide and 2,6-dicarboxy-4-methylphenol to a glass bottle, then add an organic solution to obtain mixture A; S2: Disperse the mixture A obtained in S1 evenly, then add the catalyst for catalysis. After the addition is complete, seal the glass bottle with the cap to obtain mixture B. S3: The mixture B obtained in S2 is reacted under specified temperature conditions. After the reaction is completed, the generated solid is transferred to a centrifuge tube, washed three times with tetrahydrofuran and acetone solvents respectively, and then naturally dried to obtain a yellow solid product, namely the clover-type covalent organic framework material.

[0006] Further, the organic solution in step S1 is one or more of 1,4-dioxane, acetonitrile, ethanol, chloroform, n-butanol, mesitylene, and o-dichlorobenzene.

[0007] Further, in step S2, mixture A is ultrasonically sonicated for 20 min to disperse the solution evenly.

[0008] Furthermore, the catalyst in step S2 is one or more of acetic acid, trifluoroacetic acid, trifluoromethanesulfonic acid, and p-toluenesulfonic acid.

[0009] Further, in step S1, the total concentration of the pyromellitic trihydrazide and 2,6-dicarboxy-4-methylphenol is 10-200 mg / ml, the molar amount of the pyromellitic trihydrazide is 0.5-30 times that of the 2,6-dicarboxy-4-methylphenol, and the molar amount of the catalyst is 0.5-30 times that of the 2,6-dicarboxy-4-methylphenol.

[0010] Furthermore, in step S3, the specified temperature conditions are 0-150°C, and the reaction occurs in a reactor under normal pressure or in a sealed environment, with a reaction time of 1-7 days.

[0011] This invention provides a clover-shaped covalent organic framework material, which is prepared by the aforementioned method for preparing clover-shaped covalent organic framework materials. This clover-shaped covalent organic framework material is used as an ion recognition sensor. This novel structure combines monomer functionalization and material functionalization, exhibiting excellent fluorescence properties and the ability to recognize metal ions, specifically for detecting and recognizing Fe. 3+ .

[0012] Compared with existing technologies, one or more of the above technical solutions have the following beneficial effects: This invention utilizes the reaction of pyromellitic tricarboxyhydrazide and 2,6-dicarboxy-4-methylphenol to prepare a novel cloverleaf-shaped covalent organic framework material. This covalent organic framework, in addition to possessing long-range order and a regular pore structure, also exhibits a large π-conjugated structure, which endows it with excellent mass transfer and light absorption properties. Based on this, the invention provides a method for applying this cloverleaf-shaped covalent organic framework material to the detection of Fe in water. 3+ This allows the material to be used as a fluorescent probe to identify Fe. 3+ This leads to fluorescence quenching, exhibiting sensitive fluorescence response behavior, thus enabling effective detection of Fe in wastewater. 3+ It has good effects when used. Attached Figure Description

[0013] 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.

[0014] Figure 1 This is the powder X-ray diffraction pattern of the clover-shaped covalent organic framework material synthesized in this invention.

[0015] Figure 2 This is a structural simulation diagram of the clover-shaped COF material synthesized in this invention.

[0016] Figure 3 This is the Fourier transform infrared spectrum of the clover-shaped covalent organic framework material synthesized in this invention.

[0017] Figure 4 This is a SEM image of the clover-shaped covalent organic framework material synthesized in this invention.

[0018] Figure 5 This is a thermogravimetric curve of the clover-shaped covalent organic framework material synthesized in this invention.

[0019] Figure 6 This is the fluorescence spectrum of the clover-shaped covalent organic framework material synthesized in this invention for different metal ions.

[0020] Figure 7 The clover-shaped covalent organic framework material synthesized in this invention is obtained at different concentrations of Fe. 3+ The fluorescence spectrum below.

[0021] Figure 8 This is a fluorescence quenching diagram of the clover-shaped covalent organic framework material synthesized in this invention under ultraviolet light irradiation.

[0022] Figure 9 This is a structural diagram of the clover-shaped covalent organic framework material synthesized in this invention. Detailed Implementation

[0023] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0024] Example 1:

[0025] A method for preparing a clover-shaped covalent organic framework material, specifically comprising: Tristyridine hydrazide (15.2 mg, 0.06 mmol) and 2,6-dicarboxy-4-methylphenol (14.8 mg, 0.09 mmol) were added to a glass bottle, followed by the addition of 0.5 mL of ethanol and 0.5 mL of trimethylbenzene to obtain a mixture. The mixture was sonicated for 20 min to ensure uniform dispersion. Then, 0.2 mL of 1M CF3SO3H solution was added. After the addition was complete, the glass bottle was sealed with a cap and reacted at room temperature for 3 days. After the reaction was completed, the solid was transferred to a centrifuge tube and washed three times with tetrahydrofuran and acetone solvents, respectively. After natural drying, a yellow solid product was obtained, which is the clover-shaped covalent organic framework material.

[0026] Example 2: A method for preparing a clover-shaped covalent organic framework material, specifically comprising: Tristyridine hydrazide (15.2 mg, 0.06 mmol) and 2,6-dicarboxy-4-methylphenol (14.8 mg, 0.09 mmol) were added to a glass bottle, followed by the addition of 0.5 mL of acetonitrile and 0.5 mL of o-dichlorobenzene to obtain a mixture. The mixture was sonicated for 20 min to ensure uniform dispersion, and then 0.2 mL of 1M AcOH solution was added. After the addition was complete, the glass bottle was sealed with a cap and reacted at 50 °C for 5 days. After the reaction was completed, the resulting solid was transferred to a centrifuge tube and washed three times with tetrahydrofuran and acetone solvents, respectively. After natural drying, a yellow solid product was obtained, which is the clover-shaped covalent organic framework material.

[0027] Example 3: A method for preparing a clover-shaped covalent organic framework material, specifically comprising: Tristyracil (15.2 mg, 0.06 mmol) and 2,6-dicarboxy-4-methylphenol (14.8 mg, 0.09 mmol) were added to a glass bottle, followed by the sequential addition of 0.5 mL of n-butanol and 0.5 mL of 1,4-dioxane to obtain a mixture. The mixture was sonicated for 20 min to ensure uniform dispersion, and then 0.2 mL of 1M p-toluenesulfonic acid solution was added. After the addition was complete, the glass bottle was sealed with a cap and reacted at 80 °C for 2 days. After the reaction was completed, the resulting solid was transferred to a centrifuge tube, washed three times with tetrahydrofuran and acetone solvents, and then air-dried to obtain a yellow solid product, which is the clover-shaped covalent organic framework material.

[0028] Specifically, the synthetic formula of the clover-shaped covalent organic framework material is shown below:

[0029] Example 4: Unless otherwise specified, the clover-shaped covalent organic framework material prepared by the method described in this invention is named COF-ZKNU11 in the specification. Fe 3+ Fluorescence recognition test: 10.0 mg of thoroughly ground COF-ZKNU11 sample was uniformly dispersed in 10.0 mL of deionized water and sonicated for 20 min to obtain a COF-ZKNU11 suspension for later use. 2.9 mL of the COF-ZKNU11 suspension was placed in a quartz cuvette, and then 15 different 0.1 mL 0.01 μM aqueous solutions of metal ions (including Li) were added separately. + Na + K + Ag + Mg 2+ Ca 2+ Fe 2+ Co 2+ Ni 2+ Cu 2+ Zn 2+ Mn 2+ Pb 2+ Ba 2+ and Fe 3+ Fifteen metal ions were added to a cuvette, and the changes in their fluorescence intensity were tested at room temperature.

[0030] As can be seen from the fluorescence curve (e.g.) Figure 6 As shown in the figure, most metal ions did not affect the fluorescence intensity of the COF-ZKNU11 suspension. When the added metal ion was Li... + Na + K + Ag + Mg 2+ Ca 2+ Zn 2+ Mn 2+ Pb 2+ Ba 2+ When Fe was added, the fluorescence intensity of its COF-ZKNU11 suspension remained essentially unchanged; however, when Fe was added... 2+ Co 2+ Ni 2+ Cu 2+ At that time, the fluorescence intensity of the COF-ZKNU11 suspension decreased slightly; however, the addition of Fe to the COF-ZKNU11 suspension... 3+ The fluorescence intensity of the ions decreased most significantly, which may be due to the interaction of N, O and Fe in COF-ZKNU11. 3+ Strong interactions between ions lead to fluorescence quenching.

[0031] also, Figure 1 In the comparison of the powder X-ray diffraction patterns of the clover-shaped material, it can be seen that the material has a crystalline form; Figure 3 In the image, a is the infrared spectrum of pyromellitic trimethylhydrazine, b is the infrared spectrum of 2,6-diformyl-4-methylphenol, and c is the infrared spectrum of the cloverleaf-shaped material. Figure 3 The formation of acylhydrazone bonds can be understood from this; Figure 4 The data indicates that the material has a uniform strip-like morphology; Figure 5 This indicates that the material has a certain degree of thermal stability; Figure 6 The data shows that this material has selective recognition of ferric ions; Figure 7 In the process, different concentrations of Fe were added to the COF-ZKNU11 suspension. 3+ The fluorescence intensity of the COF-ZKNU11 suspension was determined by the solution reaction and increased with Fe. 3+ Ion concentration (0-120) It decreases with the increase of μm; Figure 8 In the study, COF-ZKNU11 showed a clear fluorescence quenching effect under ultraviolet light (λex=365 nm), exhibiting a significant intensity change.

[0032] Therefore, this invention utilizes the reaction of pyromellitic tricarboxyhydrazide and 2,6-dicarboxy-4-methylphenol to prepare a novel clover-shaped covalent organic framework material. This covalent organic framework, in addition to possessing long-range order and a regular pore structure, also exhibits a large π-conjugated structure, which endows it with excellent mass transfer and light absorption properties. Based on this, the invention provides a method for applying this clover-shaped covalent organic framework material to the detection of Fe in water. 3+ This allows the material to be used as a fluorescent probe to identify Fe. 3+ This leads to fluorescence quenching, exhibiting sensitive fluorescence response behavior, thus enabling effective detection of Fe metal in wastewater. 3+ It has good effects when used.

[0033] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing a covalent organic framework material, characterized in that, Includes the following steps: S1: Add pyromellitic trihydrazide and 2,6-dicarboxy-4-methylphenol to a glass bottle, then add an organic solution to obtain mixture A; S2: Disperse the mixture A obtained in S1 evenly, then add the catalyst for catalysis. After the addition is complete, seal the glass bottle with the cap to obtain mixture B. S3: The mixture B obtained in S2 is reacted under specified temperature conditions. After the reaction is completed, the solid generated is transferred to a centrifuge tube, washed three times with tetrahydrofuran and acetone solvents respectively, and then naturally dried to obtain a covalent organic framework material.

2. The method for preparing the covalent organic framework material according to claim 1, characterized in that: The organic solution in step S1 is one or more of 1,4-dioxane, acetonitrile, ethanol, chloroform, n-butanol, mesitylene, and o-dichlorobenzene.

3. The method for preparing the covalent organic framework material according to claim 1, characterized in that: In step S2, mixture A is ultrasonically sonicated for 20 min to disperse the solution evenly.

4. The method for preparing the covalent organic framework material according to claim 1, characterized in that: The catalyst in step S2 is one or more of acetic acid, trifluoroacetic acid, trifluoromethanesulfonic acid, and p-toluenesulfonic acid.

5. The method for preparing the covalent organic framework material according to claim 1, characterized in that: In step S1, the total concentration of the pyromellitic trihydrazide and 2,6-dicarboxy-4-methylphenol is 10-200 mg / ml, the molar amount of the pyromellitic trihydrazide is 0.5-30 times that of the 2,6-dicarboxy-4-methylphenol, and the molar amount of the catalyst is 0.5-30 times that of the 2,6-dicarboxy-4-methylphenol.

6. The method for preparing the covalent organic framework material according to claim 1, characterized in that: In step S3, the specified temperature conditions are 0-150℃, and the reaction occurs in a normal pressure or sealed reactor for 1-7 days.

7. A covalent organic framework material, characterized in that: The covalent organic framework material is prepared by the preparation method of the covalent organic framework material according to any one of claims 1-6; the covalent organic framework material is used to detect and identify Fe. 3+ .

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