A framework isomer of a cofs material, and preparation method and application thereof

Abstract

The application discloses a kind of COFs material framework isomer and its preparation method and application, belong to covalent organic framework material and analytical detection field.The COFs material framework isomer is BATD-Dma-COF K and BATD-Dma-COF R, and the raw material for preparation is D2h symmetry monomer tetraphenylamino benzene, C2 symmetry monomer 2,5-dimethoxy benzene-1,4-diformaldehyde.BATD-Dma-COF K can be synthesized by hot solvent method and room temperature solvent method, and BATD-Dma-COF R is synthesized by hot solvent method;By the method for adding benzyl alcohol, aniline regulator regulator or controlling reaction time during synthesis, the morphology of BATD-Dma-COF K, BATD-Dma-COF R is accurately controlled;The morphology of irregular granular BATD-Dma-COF K and hollow spherical BATD-Dma-COF R obtained by the method of the application can be used for the detection of Pb 2+ ion in aqueous solution.

Description

TECHNICAL FIELD

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

[0002] Covalent organic framework materials (COFs) are composed of light elements (e.g. B, C, Si, N and O) by strong covalent bonds (e.g. B-O, C-N, C=N and C=C-N) connecting organic units, which are synthesized by thermodynamically controlled reversible polymerization reactions. The topology of covalent organic framework materials is generally considered to be determined by the symmetry of the reaction monomers that undergo condensation. In this case, COFs materials with different topologies can be provided by using reaction monomers with different symmetries according to different needs. In addition, the formation of the connecting bonds of COFs materials is a kind of dynamic reversible reaction. Therefore, when the reaction monomers have multiple connection modes, the distribution of different products is mainly due to the energy difference of different products. That is, the lowest energy produces the most stable product, and if the energy gap is large enough, it will be the only product compared with other possible structural isomers.

[0003] From the perspective of topology, condensation of D2h symmetric monomers and C2 symmetric monomers will generate two crystal systems: one is an orthorhombic system with only a single uniform size of pores in the periodic framework, and the other is a hexagonal system with two different types of pores. In addition, each system can be further divided into two structures: overlapping and interlaced. Therefore, there will be four possible structures that can be generated. Under the condition of thermodynamic control, the product that can be synthesized by this system depends on the energy difference of the four products, so if the energy difference between the products is large enough, the only product with the lowest energy can be synthesized.

[0004] The framework isomer of COFs material refers to a structure with the same molecular formula and chemical composition but different spatial atomic arrangement. In this case, isomers usually exhibit different physical and chemical properties. However, although several types of framework isomers in COFs have been synthesized by experiments, the number of framework isomers is very limited, and their synthesis can only rely on luck. Wang and colleagues synthesized the first example of three-dimensional COF interpenetrating isomers, but in this report only the solvent system was studied, and the influence of other conditions was unknown, and the change of its micro-morphology has not been reported. Since the isomerism phenomenon is an important phenomenon in COFs materials and basic chemistry, it is very necessary to find other types of COFs isomers and explore their morphology differences and regulation. SUMMARY

[0005] In order to overcome the technical problems existing in the background art, the present application provides a COFs material framework isomer and a preparation method and application thereof, which uses D2h symmetric monomer tetraanilinium benzene (BATD) and C2 symmetric monomer 2,5-dimethoxybenzene-1,4-diformaldehyde (Dma) as raw materials, uses different methods to synthesize the only product with the lowest energy under specific conditions, realizes the synthesis of two framework isomer COFs materials, and realizes the accurate control of the morphology of the two framework isomer COFs materials by controlling the synthesis method and synthesis conditions; and uses the scattering characteristics of the two framework isomers to realize the selective detection of Pb 2+ ions in actual water samples.

[0006] In order to achieve the above-mentioned purpose, the present application is realized by the following technical scheme:

[0007] A COFs material framework isomer, the COFs material framework isomer is BATD-Dma-COF K and BATD-Dma-COF R, and the raw material for preparation is D2h symmetric monomer tetraanilinium benzene and C2 symmetric monomer 2,5-dimethoxybenzene-1,4-diformaldehyde.

[0008] One of the preparation methods of the COFs material framework isomer is to synthesize BATD-Dma-COF K and BATD-Dma-COF R by using a hot solvent method.

[0009] The specific steps for synthesizing BATD-Dma-COF K are as follows: 1) tetraanilinium benzene and 2,5-dimethoxybenzene-1,4-diformaldehyde are added into a 10.0 mL Pyrex tube; 2) methanol and acetic acid are added and shaken uniformly, and then ultrasonic treatment is performed for 10 min until the monomers are completely dispersed; 3) the mixture after being fully mixed is rapidly frozen in a liquid nitrogen bath, and after vacuumizing, the Pyrex tube is sealed and placed in a 100 DEG C constant temperature oven for reaction; 4) the product is collected by filtration, and is washed with anhydrous N,N-dimethylformamide, tetrahydrofuran respectively for 3 times, and then is washed with anhydrous acetone by centrifugation for 5 times, and after drying at 80 DEG C, yellow BATD-Dma-COF K powder is obtained.

[0010] The specific steps for synthesizing BATD-Dma-COF R are as follows: 1) tetraanilinium benzene and 2,5-dimethoxybenzene-1,4-diformaldehyde are added into a 10.0 mL Pyrex tube; 2) mesitylene and acetic acid are added and shaken uniformly, and then ultrasonic treatment is performed for 10 min until the monomers are completely dispersed; 3) it is frozen and vacuumized, and after sealing, the Pyrex tube is placed in a 100 DEG C constant temperature oven for reaction; 4) the product is collected by filtration, and is washed with anhydrous N,N-dimethylformamide, tetrahydrofuran respectively for 3 times, and then is washed with acetone by centrifugation for 5 times, and after drying at 80 DEG C, yellow BATD-Dma-COF R powder is obtained.

[0011] Further, the ratio of tetraphenylammonium benzene and 2,5-dimethoxybenzene-1,4-diformaldehyde is 1:2 when synthesizing the BATD-Dma-COF K and the BATD-Dma-COF R.

[0012] Further, the constant temperature reaction time for synthesizing the BATD-Dma-COF K is 3-8d, and the constant temperature reaction time for synthesizing the BATD-Dma-COF R is 2-8d.

[0013] The second preparation method is to synthesize the BATD-Dma-COF K by using the room temperature solvent method, and the specific steps are as follows: 1) tetraphenylammonium benzene and 2,5-dimethoxybenzene-1,4-diformaldehyde are added into a 10.0mL centrifuge tube; 2) after adding mesitylene and acetic acid and stirring uniformly, ultrasonic treatment is performed for 10min until the monomers are completely dispersed; 3) the mixture is reacted at room temperature; 4) the product is collected by filtration, and is washed with anhydrous N,N-dimethylformamide, tetrahydrofuran respectively for 3 times, and then is washed with anhydrous acetone by centrifugation for 5 times, and after drying at 80℃, yellow BATD-Dma-COF K powder is obtained.

[0014] Further, the ratio of tetraphenylammonium benzene and 2,5-dimethoxybenzene-1,4-diformaldehyde is 1:2 when synthesizing the BATD-Dma-COF K and the BATD-Dma-COF R.

[0015] When synthesizing the BATD-Dma-COF K by using the hot solvent method, benzyl alcohol and aniline regulators are added to control the morphology of the BATD-Dma-COF K, and when synthesizing the BATD-Dma-COF R, benzyl alcohol and aniline regulators are added or the reaction time is prolonged to control the morphology of the BATD-Dma-COF R.

[0016] When synthesizing the BATD-Dma-COF K by using the room temperature solvent method, benzyl alcohol and aniline regulators are added to control the morphology of the BATD-Dma-COF K.

[0017] The application of the COFs material framework isomers, the morphology of the BATD-Dma-COF K is irregular granular, the morphology of the BATD-Dma-COF R is hollow spherical, and the BATD-Dma-COF K and the BATD-Dma-COF R can be used for detecting Pb 2+ ions in an aqueous solution.

[0018] The beneficial effects of the application are as follows:

[0019] (1) The present application uses D2h symmetrical monomer tetraphenylamino benzene (BATD) and C2 symmetrical monomer 2,5-dimethoxybenzene-1,4-diformaldehyde (Dma) as raw materials, adopts a hot solvent method and a room temperature solvent method, increases the energy difference between products, synthesizes the only product with the lowest energy under specific conditions, and realizes the synthesis of two kinds of framework isomeric COF materials;

[0020] (2) The present application realizes accurate control of the morphology of two kinds of framework isomeric COFs materials by adding a regulator or controlling the reaction time during synthesis;

[0021] (3) The irregular granular BATD-Dma-COF K and the hollow spherical BATD-Dma-COF R prepared by the present application can realize selective detection of Pb 2+ ions in actual water samples. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 It is a synthesis schematic diagram of BATD-Dma-COF K and BATD-Dma-COF R;

[0023] Figure 2 It is a PXRD spectrum diagram of BATD-Dma-COF K and BATD-Dma-COF R in Example 1;

[0024] Figure 3 It is a PXRD spectrum diagram of BATD-Dma-COF K in Example 2;

[0025] Figure 4 It is a MS simulated PXRD spectrum diagram and a refined structure diagram of BATD-Dma-COF K in Example 1;

[0026] Figure 5 It is a MS simulated PXRD spectrum diagram and a refined structure diagram of BATD-Dma-COF R in Example 1;

[0027] Figure 6 It is a TEM diagram of BATD-Dma-COF K synthesized in Example 1;

[0028] Figure 7 It is a TEM diagram of BATD-Dma-COF K synthesized in Example 3;

[0029] Figure 8 It is a TEM diagram of BATD-Dma-COF K synthesized in Example 2;

[0030] Figure 9 It is a TEM diagram of BATD-Dma-COF K synthesized in Example 4;

[0031] Figure 10 TEM image of BATD-Dma-COF R synthesized for Example 1;

[0032] Figure 11 TEM image of BATD-Dma-COF R synthesized for Example 5;

[0033] Figure 12 TEM image of BATD-Dma-COF R synthesized for Example 6;

[0034] Figure 13 Schematic diagram of the influence of different metal ions on the scattering of BATD-Dma-COF K and BATD-Dma-COF R;

[0035] Figure 14 Linear relationship diagram of the enhancement of different concentrations of Pb 2+ ions on the scattering of BATD-Dma-COF K and BATD-Dma-COF R. DETAILED DESCRIPTION

[0036] The application will be further described in conjunction with specific embodiments, but the scope of protection of the application is not limited to the described content.

[0037] Example 1

[0038] BATD-Dma-COF K and BATD-Dma-COF R were synthesized by a hot-solvent method, and the specific steps were as follows:

[0039] Synthesis of BATD-Dma-COF K: Tetraaniliniumbenzene (BATD) (13.28 mg, 0.03 mmol) and 2,5-dimethoxybenzene-1,4-dicarboxaldehyde (Dma) (11.65 mg, 0.06 mmol) were added into a 10.0 mL Pyrex tube; after being shaken uniformly, methanol (3.0 mL) and acetic acid (0.8 mL, 6M) were added and ultrasonic treatment was performed for 10.0 min until the monomers were completely dispersed; the mixture after being mixed sufficiently was rapidly frozen in a liquid nitrogen bath, and after being vacuumized, the Pyrex tube was sealed and placed in a constant temperature oven at 100℃ for reaction for 5 days; the product was collected by filtration, and was washed with anhydrous N,N-dimethylformamide (DMF), tetrahydrofuran respectively for 3 times, and then was centrifugally washed with anhydrous acetone for 5 times, and after being dried at 80℃, yellow BATD-Dma-COF K powder was obtained.

[0040] The synthesis schematic diagram of BATD-Dma-COF K is shown in Figure 1 The PXRD diagram of the synthesized BATD-Dma-COF K is shown in Figure 2wherein the abscissa represents the 2 theta diffraction angle and the ordinate represents the diffraction peak intensity; the strongest diffraction peak of the PXRD pattern of the BATD-Dma-COF K material at 2.37° corresponds to the (100) crystal face, while the three weaker signal peaks at 4.13°, 4.78° and 7.26° are attributed to the (110), (200) and (210) crystal faces, respectively.

[0041] The structure of the synthesized BATD-Dma-COF K was simulated by the Materials Studio (MS) software, and the results are shown in Figure 4 (A) PXRD pattern of the experimentally obtained BATD-Dma-COF K, MS simulated PXRD pattern based on the AA-stacking model, MS simulated PXRD pattern based on the AB-stacking model; (B) schematic diagram of the AA-stacking structure of the BATD-Dma-COF K (left), schematic diagram of the AB-stacking structure of the BATD-Dma-COF K (right); (C) Pawley refinement results of the BATD-Dma-COF K; (D) schematic diagram of the structure of the BATD-Dma-COF K after refinement. The initial unit cell parameters are α = 90°, β = 90°, γ = 120°. The initial unit cell parameters of the BATD-Dma-COF K are α = 90°, β = 90°, γ = 120°. The structure of the BATD-Dma-COF K is an AA-stacking model structure, and its space group is P3. After the Pawley refinement, the weighted R factor of the unit cell parameters of the BATD-Dma-COF K is: Rwp = 3.65%, Rp = 8.95%. From the structure diagram after refinement, the theoretical pore size of the large pore of the BATD-Dma-COF K is the theoretical pore size of the small pore is the interlayer distance is

[0042] The morphology of the synthesized BATD-Dma-COF K is shown in Figure 6 and is an irregular granular structure.

[0043] Synthesis of BATD-Dma-COF R: Tetraanisole (BATD) (13.28 mg, 0.03 mmol), 2,5-dimethoxybenzene (Dma) (11.65 mg, 0.06 mmol) were added into a 10.0 mL Pyrex tube; followed by the addition of mesitylene (3.0 mL) and acetic acid (0.2 mL, 6 M) and sonicated until the monomers were completely dispersed, then the tube was frozen and evacuated, sealed and placed in a 100 °C oven for 5 days; the product was collected by filtration and washed with anhydrous N,N-dimethylformamide (DMF), tetrahydrofuran (THF) for 3 times, respectively, and then washed with acetone for 5 times by centrifugation, and dried at 80 °C to obtain yellow BATD-Dma-COF R powder.

[0044] Synthetic scheme of BATD-Dma-COF R is shown in Figure 1 PXRD pattern of the synthesized BATD-Dma-COF R is shown in Figure 2 wherein the abscissa represents the 2θ diffraction angle, and the ordinate represents the diffraction peak intensity; the PXRD pattern of the BATD-Dma-COF R material has the strongest diffraction peak at 4.791°, which corresponds to the (110) crystal face, and the three signal peaks at 6.917°, 9.631° and 12.761° can be attributed to the (200), (220) and (150) crystal faces, respectively.

[0045] The structure of the synthesized BATD-Dma-COF R is shown in Figure 5

(A) PXRD spectrum of the experimentally obtained BATD-Dma-COF R, MS simulated PXRD spectrum based on AA-stacking model, MS simulated PXRD spectrum based on AB-stacking model; (B) AA-stacking structure schematic diagram of BATD-Dma-COF R (left), AB-stacking structure schematic diagram of BATD-Dma-COF R (right); (C) Pawley refinement result of BATD-Dma-COF R; (D) structure schematic diagram of the refined BATD-Dma-COF R

[0046] Morphology of the synthesized BATD-Dma-COF K is shown in Figure 10 ​irregular blocky particles.

[0047] Example 2

[0048] BATD-Dma-COF K was synthesized by room temperature solvent method, and the specific steps were as follows:

[0049] Tetraphenylammonium benzene (BATD) (13.28 mg, 0.03 mmol) and 2,5-dimethoxybenzene (Dma) (11.65 mg, 0.06 mmol) were added to a 10.0 mL centrifuge tube; after adding mesitylene (5.0 mL) and acetic acid (0.4 mL, 12M) and shaking uniformly, ultrasonic treatment was performed for 10 minutes until the monomers were completely dispersed, and reaction was performed at room temperature for 5 days; the product was collected by filtration and washed with anhydrous N,N-dimethylformamide (DMF), tetrahydrofuran, respectively, 3 times, and then washed with anhydrous acetone by centrifugation 5 times, and yellow BATD-Dma-COF K powder was obtained after drying at 80°C.

[0050] The PXRD pattern of BATD-Dma-COF K synthesized in this example is shown in Figure 3 , and the morphology is shown in Figure 8 Irregular hollow sphere structure assembled by irregular long strip-shaped particles can be seen from the figure, and the assembled channel structure can be clearly seen. It can also be found that the crystallinity of BATD-Dma-COF K synthesized at room temperature decreases, and the crystal lattice stripe is not clear.

[0051] Example 3

[0052] BATD-Dma-COF K was synthesized by hot solvent method, and the morphology was regulated by adding a regulator, and the specific steps were as follows:

[0053] Tetraphenylammonium benzene (BATD) (13.28 mg, 0.03 mmol) and 2,5-dimethoxybenzene-1,4-diformaldehyde (Dma) (11.65 mg, 0.06 mmol) were added to a 10.0 mL Pyrex tube; methanol (3.0 mL) was added and shaken uniformly, and then benzaldehyde (35 μL) and aniline (35 μL) were added and shaken uniformly; then acetic acid (0.8 mL, 6M) was added and shaken uniformly, and ultrasonic treatment was performed for 10.0 min until the monomers were completely dispersed, and the well-mixed mixture was rapidly frozen in a liquid nitrogen bath, and after vacuumizing, the Pyrex tube was sealed and placed in a 100°C constant temperature oven for reaction for 5 days; the product was collected by filtration and washed with anhydrous N,N-dimethylformamide (DMF), tetrahydrofuran, respectively, 3 times, and then washed with anhydrous acetone by centrifugation 5 times, and yellow BATD-Dma-COF K powder was obtained after drying at 80°C.

[0054] The morphology of BATD-Dma-COF K synthesized in this example is shown inFigure 7 After adding the regulator, the originally irregular granular shape still exists, but the granular assembly forms a larger sheet structure.

[0055] Example 4

[0056] The BATD-Dma-COF K was synthesized by a room temperature solvent method, and its morphology was regulated by adding a regulator. The specific steps are as follows:

[0057] Tetraphenylamino benzene (BATD) (13.28 mg, 0.03 mmol) and 2,5-dimethoxybenzene (Dma) (11.65 mg, 0.06 mmol) were added to a 10.0 mL centrifuge tube; after being uniformly shaken with mesitylene (5.0 mL), benzaldehyde (35 μL) and aniline (35 μL) were added respectively and shaken; then after being uniformly shaken with acetic acid (0.4 mL, 12M), ultrasonic treatment was performed for 10.0 min until the monomers were completely dispersed, and reaction was performed at room temperature for 5 days; the product was collected by filtration, and washed with anhydrous N,N-dimethylformamide (DMF), tetrahydrofuran respectively for 3 times, and then washed with anhydrous acetone by centrifugation for 5 times, and yellow BATD-Dma-COF K powder was obtained after drying at 80°C.

[0058] The morphology of the BATD-Dma-COF K synthesized in this example is shown in Figure 9 After adding the regulator, the originally irregular granular shape still exists, but the granular assembly forms a larger sheet structure.

[0059] Example 5

[0060] The BATD-Dma-COF R was synthesized by a hot solvent method, and its morphology was regulated by adding a regulator. The specific steps are as follows:

[0061] Tetraphenylamino benzene (BATD) (13.28 mg, 0.03 mmol) and 2,5-dimethoxybenzene (Dma) (11.65 mg, 0.06 mmol) were added to a 10.0 mL Pyrex tube; after being uniformly shaken with mesitylene (3.0 mL), benzaldehyde (35 μL) and aniline (35 μL) were added respectively and shaken; then after being uniformly shaken with acetic acid (0.2 mL, 6M), ultrasonic treatment was performed for 10 min until the monomers were completely dispersed, and then the Pyrex tube was frozen and vacuumized, sealed and placed in a 100°C constant temperature oven for reaction for 5 days; the product was collected by filtration, and washed with anhydrous N,N-dimethylformamide (DMF), tetrahydrofuran respectively for 3 times, and then washed with acetone by centrifugation for 5 times, and yellow BATD-Dma-COF R powder was obtained after drying at 80°C.

[0062] The morphology of the BATD-Dma-COF R synthesized in this example is shown inFigure 11 After the addition of the modifier, the BATD-Dma-COF R material has a rod-shaped structure with a size of more than 2μm and a regular morphology.

[0063] Example 6

[0064] BATD-Dma-COF R was synthesized using a hot solvent method, and its morphology was controlled by extending the reaction time. The specific steps are as follows:

[0065] Tetraphenylaminobenzene (BATD) (13.28 mg, 0.03 mmol) and 2,5-dimethoxybenzene (Dma) (11.65 mg, 0.06 mmol) were added to a 10.0 mL Pyrex tube; then 3.0 mL of mesitylene and 0.2 mL of acetic acid (6 M) were added, and the mixture was shaken and sonicated for 10 minutes until the monomers were completely dispersed. The tube was then frozen and vacuum-sealed, and the Pyrex tube was placed in a 100 °C oven for 7 days. The product was collected by filtration and washed three times each with anhydrous N,N-dimethylformamide (DMF) and tetrahydrofuran, and then washed five times with acetone by centrifugation. After drying at 80 °C, a yellow BATD-Dma-COF R powder was obtained.

[0066] The morphology of the synthesized BATD-Dma-COF R in this embodiment is shown in the figure. Figure 12 After extending the reaction time, the originally irregular granular structure is transformed into a smooth hollow sphere structure, and the assembly channels can be clearly seen.

[0067] Example 7

[0068] The BATD-Dma-COF K synthesized in Example 1 and the BATD-Dma-COF R synthesized in Example 6 were used to detect Pb in aqueous solution. 2+ ion.

[0069] Take 20.0 μL of BATD-Dma-COF K and BATD-Dma-COF R suspensions at a concentration of 1.0 mg / mL dispersed in anhydrous ethanol into a 1.5 mL centrifuge tube, and then add a series of Pb solutions of different concentrations. 2+ The ions were then diluted with water to a final volume of 1.0 mL. The mixture was shaken thoroughly and allowed to react for 15.0 min. The change in scattering intensity was then measured.

[0070] Pb 2+ The scattering intensity of BATD-Dma-COF R is reduced by ions (see...) Figure 13 and Figure 14 Different concentrations of Pb 2+ Linear relationship of ion-enhanced BATD-Dma-COF K scattering (A, B); Pb at different concentrations 2+Linear relationship graph (C, D) of ion-enhanced BATD-Dma-COF R scattering, wherein the abscissa represents metal ions, and the ordinate represents scattering intensity reduction. Figure 13 In the above-mentioned examples, after various metal ions interact with BATD-Dma-COF K and BATD-Dma-COF R, only Pb(II) ions can greatly enhance the scattering intensity of the two materials, and there is no obvious change in scattering signal in the presence of other cations. This indicates that BATD-Dma-COF K and BATD-Dma-COF R have good detection selectivity for Pb(II) ions. Figure 14 In the above-mentioned examples, after the addition of Pb(II) ion solution, the scattering intensity of BATD-Dma-COF K gradually increases with the increase of the concentration of Pb(II) ions; and in the concentration range of 2.0-250.0 μM, the scattering intensity of BATD-Dma-COF K has a good positive proportion relationship with the concentration of added Pb(II) ions. The linear regression equation of the fitting is △I = 2.2173CPb(II) + 7.7837, and the correlation coefficient R2 is 0.9910. Similarly, the addition of Pb(II) ion solution to the suspension of BATD-Dma-COF R also enhances the scattering, and is proportional to the concentration of added Pb(II) ions. In the concentration range of 2.0-60.0 μM, the scattering intensity of BATD-Dma-COF R has a good linear relationship with the concentration of Pb(II) ions. The calibration curve is △I = 13.0587CPb(II) + 8.1115, and the correlation coefficient (R2) is 0.9972.

[0071] The present application uses D2h symmetric monomer tetraanilinium benzene (BATD) and C2 symmetric monomer 2,5-dimethoxybenzene-1,4-diformaldehyde (Dma) as raw materials, and synthesizes the only product with the lowest energy under specific conditions by using different methods, so as to realize the synthesis of two framework isomeric COFs materials; and by controlling the synthesis method and synthesis conditions, the morphology of the two framework isomeric COFs materials is accurately controlled; and by using the scattering characteristics of the morphologies of the two framework isomers, selective detection of Pb 2+ ions in actual water samples is realized.

[0072] Finally, it should be pointed out that the above preferred embodiments are only used to illustrate the technical solutions of the present application but not to limit the present application, and although the present application 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 application.

Claims

1. An application of a COFs material framework isomer, characterized in that: The COFs framework isomers are BATD-Dma-COF K and BATD-Dma-COF R, and the raw materials for preparation are the D2h symmetrical monomer tetraphenylaminobenzene and the C2 symmetrical monomer 2,5-dimethoxybenzene-1,4-dicarboxaldehyde; BATD-Dma-COF K and BATD-Dma-COF R are synthesized by a hot solvent method. The specific steps for synthesizing BATD-Dma-COF K are as follows: 1) Tetraphenylaminobenzene and 2,5-dimethoxybenzene-1,4-dicarboxaldehyde are added to a 10.0 mL Pyrex tube; 2) Methanol and acetic acid are added, shaken until homogeneous, and then sonicated for 10 min until the monomer is completely dispersed; 3) The thoroughly mixed mixture is placed in a liquid nitrogen bath and rapidly frozen. After vacuuming, the Pyrex tube is sealed and placed in a 100℃ constant temperature oven for reaction; 4) The product is collected by filtration and washed three times each with anhydrous N,N-dimethylformamide and tetrahydrofuran, and then washed five times with anhydrous acetone by centrifugation. After drying at 80℃, yellow BATD-Dma-COF K powder is obtained, which has an irregular granular morphology. The specific steps for synthesizing BATD-Dma-COF R are as follows: 1) Tetraphenylaminobenzene and 2,5-dimethoxybenzene-1,4-dicarboxaldehyde are added to a 10.0 mL Pyrex tube; 2) Tris(methylbenzene) and acetic acid are added, shaken until homogeneous, and then sonicated for 10 min until the monomer is completely dispersed; 3) The tube is frozen and vacuum-sealed, and then placed in a 100℃ constant temperature oven for reaction; 4) The product is collected by filtration and washed three times each with anhydrous N,N-dimethylformamide and tetrahydrofuran, and then washed five times with acetone by centrifugation. After drying at 80℃, a yellow BATD-Dma-COF R powder with a hollow spherical morphology is obtained. BATD-Dma-COF K with irregular granular morphology and BATD-Dma-COF R with hollow spherical morphology can be used for Pb in aqueous solution. 2+ Ion detection.

2. The application of a COFs material framework isomer according to claim 1, characterized in that: When synthesizing BATD-Dma-COF K and BATD-Dma-COF R, the molar ratio of tetraphenylaminobenzene and 2,5-dimethoxybenzene-1,4-dicarboxaldehyde is 1:2.

Images