A yellow-green fluorescent COFs material, its preparation method and application

Abstract

The present invention discloses a yellow-green fluorescent COFs material, its preparation method and application, belonging to the fields of covalent organic framework materials and analytical detection. In the present invention, 4,4',4'',4'''-(ethene-1,1,2,2-tetrayl)tetraphenylaldehyde (ETBA) and a flexible organic monomer 4,4'-diaminodiphenyl ether (ODA) with chelating sites are used as raw materials, methanol and acetic acid are added and shaken for dispersion, frozen with liquid nitrogen, evacuated and reacted in a constant temperature oven, the product is collected by filtration, washed with anhydrous N,N-dimethylformamide and tetrahydrofuran respectively, and then centrifuged and washed with anhydrous acetone, the solid product is collected, dried in an oven to obtain yellow ETBA-ODA-COF powder. The present invention regulates the π-π interaction in the COF structure, synthesizes a kind of ETBA-ODA-COF material with yellow-green fluorescence, and can establish a fluorescent nanoprobe to realize the analysis and detection of metal Fe 3+ , Hg 2+ ions and folic acid small molecules.

Description

Technical Field

[0001] The present invention belongs to the fields of covalent organic framework materials and analytical detection, and specifically relates to a yellow-green fluorescent COFs material, a preparation method thereof, and an application thereof. Background Art

[0002] Covalent organic framework materials (COFs) are a new type of porous crystalline polymer. Compared with traditional materials, COFs materials have some unique properties, such as a large surface area, pre-designed pore geometries, excellent crystallinity, inherent adaptability, and a high degree of flexibility in structural and functional design. Therefore, the range of properties of COFs materials has rapidly expanded to include numerous applications from energy to the environment.

[0003] Due to the wide application of luminescent materials in analytical detection, luminescent small molecules such as metal nanoclusters, carbon dots, perovskites, and biological probes have been deeply studied. However, they have disadvantages such as low sensitivity, poor stability, and non-reusability, and their applications are greatly limited. In contrast, luminescent polymers have a high possibility of solving the disadvantages of luminescent small molecule substances. Among them, compared with traditional one-dimensional or three-dimensional polymer systems, the uniqueness of COFs materials lies in the ability to pre-design the luminescent sequence. The two-dimensional porous crystal structure can provide a large specific surface area, enabling analytes to fully interact with recognition sites, thereby improving sensitivity. Since the periodic pores of COFs materials promote mass transfer, the interference of potential competitors can be eliminated, so pre-screening and pre-separation effects can be achieved. In addition, COFs materials can complementarily utilize the ordered π structure for exciton migration and use nanopores for guest hosting to form composite materials with strong fluorescence. So far, a large number of studies have reported the fluorescence properties and analytical applications of COFs materials by fluorescence quenching or fluorescence enhancement caused by guest molecules or ions. These results indicate that COFs materials have great application prospects in the quantitative analysis of environmental samples. For example, the analysis and detection of explosives, heavy metal ions, and biological small molecule compounds. Therefore, COFs materials are favored by fluorescence sensor researchers.

[0004] According to current research reports, there are still many problems to be solved in the study of COFs fluorescent materials. First, due to the π-π layered stacking structure of COFs materials, the chromophores are closely packed, resulting in low luminescence efficiency or even complete non-luminescence of many COFs materials in the solid state, which is called the aggregation-caused quenching (ACQ) phenomenon, limiting the fluorescence performance of COFs materials. Second, how to achieve long-term stability of fluorescent COFs materials in the actual environment and the fluorescence is not interfered still needs further research. Therefore, it is necessary to find new monomers to synthesize new fluorescent COFs materials, enhance the fluorescence intensity of COFs materials, improve the detection sensitivity, and expand the application range of COFs materials for fluorescence sensing detection is a work with research potential. Summary of the Invention

[0005] To overcome the technical problems existing in the background technology, the present invention proposes a yellow-green fluorescent COFs material and its preparation method and application. Using 4,4',4”,4”'-(ethene-1,1,2,2-tetrayl)tetraphenylaldehyde (ETBA) and a flexible organic monomer 4,4′-diaminodiphenyl ether (ODA) with chelating sites as raw materials, adjusting the π-π interaction in the COF structure, a yellow-green fluorescent ETBA-ODA-COF is synthesized; the synthesized ETBA-ODA-COF material can establish a fluorescent nanoprobe to realize the analysis and detection of metal Fe 3+ , Hg 2+ ions and folic acid small molecules.

[0006] To achieve the above object, the present invention is realized by the following technical solutions:

[0007] A yellow-green fluorescent COFs material, the yellow-green fluorescent COFs material is synthesized from 4,4',4”,4”'-(ethene-1,1,2,2-tetrayl)tetraphenylaldehyde and 4,4′-diaminodiphenyl ether. The specific preparation steps are as follows:

[0008] 1) Add 4,4',4”,4”'-(ethene-1,1,2,2-tetrayl)tetraphenylaldehyde and 4,4′-diaminodiphenyl ether into a 10.0 mL Pyrex tube, then add methanol and acetic acid, shake evenly and ultrasonically treat for 10.0 min until the monomers are completely dispersed;

[0009] 2) Place the mixed solution in a liquid nitrogen bath, quickly freeze and evacuate, seal the Pyrex tube and place it in a constant temperature oven for reaction;

[0010] 3) Filter and collect the product, wash it 3 times with anhydrous N,N-dimethylformamide and tetrahydrofuran respectively, and then centrifuge and wash it 5 times with anhydrous acetone;

[0011] 4) Collect the solid product and dry it in an oven to obtain yellow ETBA-ODA-COF powder.

[0012] Further, in step 1), the dosage of 4,4',4”,4”'-(ethene-1,1,2,2-tetrayl)tetraphenylmethanal is 24.00 - 48.00 mg, 0.03 - 0.06 mmol, and the dosage of 4,4′-oxydianiline is 24.51 - 49.02 mg, 0.06 - 0.12 mmol. The dosage ratio of the two ligands is 1:2.

[0013] Further, in step 2), the temperature range of the constant-temperature oven is 20°C - 120°C, and the reaction time range is 1 - 6 d.

[0014] Further, in step 4), the temperature range of the drying oven is 60°C - 100°C.

[0015] The application of the yellow-green fluorescent COFs material as described above in the detection of Fe 3+ and Hg 2+ ions and folic acid small molecules, and the specific method steps are as follows:

[0016] 1) Weigh the ETBA-ODA-COF powder and disperse it in absolute ethanol to prepare an ETBA-ODA-COF suspension;

[0017] 2) Take the suspension and place it in multiple 1.5 mL centrifuge tubes respectively, add the water sample to be detected, and then make up the volume to 1 mL with deionized water. After reacting for 25 min, detect its fluorescence emission spectrum.

[0018] Advantages of the present invention:

[0019] The present invention uses 4,4',4”,4”'-(ethene-1,1,2,2-tetrayl)tetraphenylmethanal (ETBA) and 4,4′-oxydianiline (ODA) as raw materials to adjust the π-π interaction in the COF structure, and synthesizes an ETBA-ODA-COF material with yellow-green fluorescence; the synthesized ETBA-ODA-COF material can establish a fluorescent nanoprobe to realize the analysis and detection of metal Fe 3+ and Hg 2+ ions and folic acid small molecules. Description of the drawings

[0020] Figure 1 It is a schematic diagram of the synthesis of ETBA-ODA-COF in Example 1;

[0021] Figure 2 It is the PXRD pattern of ETBA-ODA-COF in Example 1;

[0022] Figure 3 Refinement results and structural schematic diagram of ETBA-ODA-COF in Example 1;

[0023] Figure 4 Fluorescence excitation and emission spectra of ETBA-ODA-COF in Example 1;

[0024] Figure 5 Comparison diagram of the influence of different metal ions on the fluorescence of ETBA-ODA-COF;

[0025] Figure 6 For the linear relationship diagram of the detection of Fe 3+ (A,B), Hg 2+ (C,D) and FA (E,F). Detailed implementation manners

[0026] The present invention will be further described in detail below in conjunction with specific embodiments, but the protection scope of the present invention is not limited to the content described.

[0027] Example 1

[0028] A preparation method of a yellow-green fluorescent COFs material, the specific steps are as follows:

[0029] 1) Add 4,4',4”,4”'-(ethene-1,1,2,2-tetrayl)tetraphenylaldehyde (ETBA) (24.00 mg, 0.03 mmol) and 4,4′-diaminodiphenyl ether (ODA) (24.51 mg, 0.06 mmol) into a 10.0 mL Pyrex tube, then add methanol (3.0 mL) and acetic acid (0.3 mL, 6 M), shake evenly and then perform ultrasonic treatment for 10.0 min until the monomers are completely dispersed;

[0030] 2) Place the mixed solution in a liquid nitrogen bath, quickly freeze it and evacuate it, seal the Pyrex tube and place it in a constant temperature oven at 100 °C for reaction for 2 days;

[0031] 3) Filter and collect the product, wash it 3 times with anhydrous N,N-dimethylformamide and tetrahydrofuran respectively, and then wash it 5 times by centrifugation with anhydrous acetone;

[0032] 4) Collect the solid product, dry it in an oven at 80 °C to obtain yellow ETBA-ODA-COF powder.

[0033] The synthesis schematic diagram of ETBA-ODA-COF in this example is shown in Figure 1 and the PXRD pattern of the synthesized ETBA-ODA-COF is shown in Figure 2, where the abscissa represents the 2θ diffraction angle; ETBA-ODA-COF has a strong diffraction peak at 5.68°, corresponding to the (110) crystal plane. At the same time, the weak signal peaks at 7.65°, 8.40°, 11.37°, 12.23°, 15.32°, 16.84°, 17.22° and 20.97° correspond to the (110), (200), (020), (220), (310), (400), (040), (420), (510) crystal planes respectively.

[0034] The results of the structure of the synthesized ETBA-ODA-COF in this example after simulation by Materials Studio (MS) software are shown in Figure 3 [(A) The PXRD pattern of the experimentally obtained ETBA-ODA-COF, the Pawley refinement result of ETBA-ODA-COF, and the PXRD pattern based on the AA-stacking model; (B) The schematic diagram of the structure of ETBA-ODA-COF after refinement], and the initial unit cell parameters are α = 90°, β = 136.26°, γ = 90°. The structural stacking mode of ETBA-ODA-COF is the AA-stacking model structure, and its space group is C2. After correcting the unit cell parameters of ETBA-ODA-COF by Pawley refinement, the weighted R factors can be obtained as: Rwp = 4.43%, Rp = 6.44%. From the refined structure diagram, the theoretical pore size of ETBA-ODA-COF is 1.8 nm.

[0035] The fluorescence emission spectrum of the synthesized ETBA-ODA-COF suspension in this example is shown in Figure 4 , where the abscissa represents the wavelength and the ordinate represents the fluorescence intensity; its maximum emission wavelength is 514 nm.

[0036] The synthesized ETBA-ODA-COF in this example is light yellow under natural light and yellow-green under a 365 nm ultraviolet lamp, as shown in Figure 4 the inset.

[0037] Example 2

[0038] A preparation method of a yellow-green fluorescent COFs material, the specific steps are as follows:

[0039] 1) Add 4,4',4”,4”'-(ethene-1,1,2,2-tetrayl)tetraphenylaldehyde (ETBA) (40.00 mg, 0.05 mmol) and 4,4′-diaminodiphenyl ether (ODA) (40.85 mg, 0.10 mmol) into a 10.0 mL Pyrex tube, and then add methanol (3.0

[0040] (0.3 mL, 6 M) and acetic acid (0.3 mL, 6 M) were shaken evenly and then sonicated for 10.0 min until the monomers were completely dispersed;

[0041] 2) The mixture was quickly frozen in a liquid nitrogen bath and evacuated. After sealing the Pyrex tube, it was placed in an oven at 80 °C for reaction for 2 days;

[0042] 3) The product was collected by filtration and washed 3 times each with anhydrous N,N-dimethylformamide and tetrahydrofuran, and then centrifugally washed 5 times with anhydrous acetone;

[0043] 4) The solid product was collected and dried in an oven at 60 °C to obtain yellow ETBA-ODA-COF powder.

[0044] Example 3

[0045] A method for preparing a yellow-green fluorescent COFs material, the specific steps are as follows:

[0046] 1) 4,4',4”,4”'-(Ethylene-1,1,2,2-tetrayl)tetraphenylaldehyde (ETBA) (48.00 mg, 0.06 mmol) and 4,4′-diaminodiphenyl ether (ODA) (49.02 mg, 0.12 mmol) were added to a 10.0 mL Pyrex tube, and then methanol (3.0 mL) and acetic acid (0.3 mL, 6 M) were added. After shaking evenly, it was sonicated for 10.0 min until the monomers were completely dispersed;

[0047] 2) The mixture was quickly frozen in a liquid nitrogen bath and evacuated. After sealing the Pyrex tube, it was placed in an oven at 100 °C for reaction for 4 days;

[0048] 3) The product was collected by filtration and washed 3 times each with anhydrous N,N-dimethylformamide and tetrahydrofuran, and then centrifugally washed 5 times with anhydrous acetone;

[0049] 4) The solid product was collected and dried in an oven at 100 °C to obtain yellow ETBA-ODA-COF powder.

[0050] Experimental analysis

[0051] 40.0 mg of the ETBA-ODA-COF powder synthesized in Example 1 was weighed and dispersed in 50.0 mL of anhydrous ethanol to prepare a 0.8 mg / mL ETBA-ODA-COF suspension; The suspension was taken and placed in multiple 1.5 mL centrifuge tubes, and different concentrations of Fe 3+ and Hg 2+ ions and folic acid small molecules were added, and then made up to 1 mL with deionized water. After reacting for 25 min, its fluorescence emission spectrum was detected.

[0052] Metal Fe3+ Ions, metallic Hg 2+ The fluorescence of ETBA-ODA-COF was quenched by ions, folic acid small molecules. See Figure 5 and Figure 6 , where the abscissa represents metal ions and the ordinate represents relative fluorescence intensity. From Figure 5 it can be seen that Fe 3+ ions, Hg 2+ ions, and folic acid small molecules can quench the fluorescence of ETBA-ODA-COF.

[0053] In this invention, 4,4',4”,4”'-(ethene-1,1,2,2-tetrayl)tetrabenzaldehyde (ETBA) and 4,4′-diaminodiphenyl ether (ODA) were used as raw materials to regulate the π-π interaction in the COF structure, and an ETBA-ODA-COF material with yellow-green fluorescence was synthesized; the synthesized ETBA-ODA-COF material can establish a fluorescent nanoprobe to realize the analysis and detection of metal Fe 3+ , Hg 2+ ions and folic acid small molecules.

[0054] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made in form and details without departing from the scope defined by the claims of the present invention.

Claims

1. A yellow-green fluorescent COFs material, characterized in that: The described yellow-green fluorescent COFs material is synthesized from 4,4 ',4'',4''' -(ethene-1,1,2,2-tetrayl)tetrabenzaldehyde and 4,4′-diaminodiphenyl ether. The specific preparation steps are as follows: 1) Add 4,4 ',4'',4''' -(ethene-1,1,2,2-tetrayl)tetrabenzaldehyde and 4,4′-diaminodiphenyl ether into a 10.0 mL Pyrex tube, then add methanol and acetic acid, shake evenly and perform ultrasonic treatment for 10.0 min until the monomers are completely dispersed; 2) Place the mixed solution in a liquid nitrogen bath, quickly freeze it and evacuate it. After sealing the Pyrex tube, place it in a constant temperature oven for reaction; 3) Filter to collect the product, wash it 3 times with anhydrous N, N-dimethylformamide and tetrahydrofuran respectively, and then perform centrifugal washing 5 times with anhydrous acetone; 4) Collect the solid product, dry it in an oven to obtain yellow ETBA-ODA-COF powder.

2. The yellow-green fluorescent COFs material according to claim 1, wherein: In step 1), the dosage of 4,4 ',4'',4''' -(ethene-1,1,2,2-tetrayl)tetrabenzaldehyde is 24.00 - 48.00 mg, 0.03 - 0.06 mmol, and the dosage of 4,4′-diaminodiphenyl ether is 24.51 - 49.02 mg, 0.06 - 0.12 mmol. The dosage ratio of the two ligands is 1:

2.

3. A yellow-green fluorescent COFs material according to claim 1, wherein: In step 2), the temperature range of the constant temperature oven is 20°C - 120°C, and the reaction time range is 1 - 6 d.

4. A yellow-green fluorescent COFs material according to claim 1, characterized in that: In step 4), the temperature range of the drying oven is 60°C - 100°C.

5. Use of a yellow-green fluorescent COFs material according to claim 1 in the detection of Fe 3+ , Hg 2+ ions and folic acid small molecules.

6. Use of a yellow-green fluorescent COFs material according to claim 5 in the detection of Fe 3+ , Hg 2+ ions and folic acid small molecules, characterized in that The specific method steps are as follows: 1) Weigh the ETBA-ODA-COF powder and disperse it in anhydrous ethanol to prepare an ETBA-ODA-COF suspension; 2) Take the suspension and place it in multiple 1.5 mL centrifuge tubes respectively. Add the water sample to be detected, and then make up the volume to 1 mL with deionized water. After reacting for 25 min, detect its fluorescence emission spectrum.

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