Preparation method and application of dynamic fluorescent material based on functionalized HOFs

Abstract

The invention discloses a preparation method and application of a dynamic fluorescent material based on functionalized HOFs, and relates to the technical field of time-dependent dynamic response fluorescent materials. Free carboxyl on HOFs is modified by fluorescent molecule naphthalimide, and the free carboxyl is combined with spiropyrane to prepare the information encryption material with the dynamic fluorescence characteristic. Naphthalimide molecules are introduced into the HOFs material by utilizing amidation reaction, so that the polarity of the framework is reduced, the stability of the framework is improved, the framework is combined with spiropyrane, and the prepared fluorescent material has a time-dependent luminescence characteristic, has a great application prospect in the fields of information encryption and anti-counterfeiting, and can be widely applied to the fields of information encryption and anti-counterfeiting. Compared with most information storage encryption materials at present, the information storage encryption material has more excellent information storage encryption functions.

Description

Technical Field

[0001] The present invention relates to the technical field of time-dependent dynamic response fluorescent materials, and in particular to a preparation method and application of a dynamic fluorescent material based on functionalized HOFs. Background Art

[0002] Developing anti-counterfeiting technology systems with higher security levels has become a top priority in combating counterfeiting and substandard products. Dynamic fluorescent anti-counterfeiting technology stands out for its unique security advantages and significant ease of identification. This technology achieves controlled changes in fluorescent characteristics in response to external physical or chemical stimuli, demonstrating a higher level of security by increasing anti-counterfeiting sophistication.

[0003] Spiropyran compounds are substances that undergo an isomerization transition from a closed-ring state (SP) to an open-ring state (MC) upon stimulation by ultraviolet light, accompanied by changes in both physical and fluorescent color. They offer numerous advantages, including low cost, fast readout speed, and reusability. Hydrogen-bonded organic frameworks (HOFs) offer advantages such as large surface area, high porosity, environmental friendliness, and ease of synthesis. Consequently, many researchers are currently using HOFs to load spiropyrans with them to enhance their photochromic properties and thus improve information encryption. However, HOFs suffer from framework instability and susceptibility to damage, and their internal polar environment can affect the isomerization of spiropyrans. Furthermore, since most HOFs lack fluorescence, HOF-loaded spiropyran systems exhibit only a single fluorescence pattern without color change, resulting in low levels of information encryption.

[0004] Therefore, how to improve the stability of the framework by modifying HOFs and at the same time make the HOFs-loaded spiropyran system have dynamic fluorescence changes to better expand the application of materials in anti-counterfeiting and information storage encryption is an important technical problem that researchers in this field urgently need to solve. Summary of the Invention

[0005] The present invention aims to provide a method for preparing and applying a dynamic fluorescent material based on functionalized HOFs to address the aforementioned problems in the prior art. This method introduces naphthalimide molecules into the HOF material through an amidation reaction, improving the stability of the HOF material and enabling the modified HOF-loaded spiropyran system to exhibit time-dependent dynamic fluorescence.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] One of the technical solutions of the present invention is a dynamic fluorescent material based on functionalized HOFs, wherein the dynamic fluorescent material based on functionalized HOFs is a HOF material modified by naphthaleneimide loaded with spiropyran (SP).

[0008] The present invention uses the fluorescent molecule naphthalimide to modify free carboxyl groups on HOFs (Hodgkin's Fibers) and then combines the naphthalimide-modified HOFs with spiropyran to prepare spiropyran-loaded naphthalimide-modified HOFs. The naphthalimide modification reduces the polarity of the HOFs and enhances their stability. Furthermore, by leveraging the inherent fluorescent properties of naphthalimide, the combination with spiropyran produces a fluorescence resonance energy transfer effect under ultraviolet irradiation, resulting in a change in fluorescence color. This, in turn, imparts time-dependent luminescence to the combined system.

[0009] Furthermore, the preparation step of the naphthalimide-modified HOFs material includes: modifying the surface of the catalyst-activated HOFs material with naphthalimide through an amidation reaction to obtain the naphthalimide-modified HOFs material (abbreviated as HOFs-graft material).

[0010] The amine groups (-NH2) in naphthalimide react with the carboxyl groups (-COOH) on the surface of the HOFs material to form amide bonds, thereby modifying the HOFs material. Catalyst activation is to activate the carboxyl groups on the surface of the HOFs material.

[0011] Furthermore, the structural formula of the naphthalene imide is

[0012] Furthermore, the naphthalene imide is prepared from 1,8-naphthalene dicarboxylic anhydride (structural formula: ) and ethylenediamine (structural formula ) is obtained by amidation reaction.

[0013] Optionally, in the amidation reaction for preparing the naphthalene imide, the reaction conditions include:

[0014] The solvent for the reaction is ethanol;

[0015] The protective gas for the reaction is nitrogen;

[0016] The reaction temperature is 75-80°C;

[0017] The reaction time is 12h.

[0018] Furthermore, the catalyst includes 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS).

[0019] Furthermore, the HOFs material is assembled through the ligand 2,4,6-tris(4-carboxyphenyl)-1,3,5-triazine (TATB).

[0020] Furthermore, the mass ratio of the naphthalimide to the HOFs material is 1:4-5.

[0021] The second technical solution of the present invention: A method for preparing the above-mentioned dynamic fluorescent material based on functionalized HOFs, comprising the following steps: dropwise adding a spiropyran solution to a naphthalimide-modified HOFs material, and drying to obtain the functionalized HOFs-based dynamic fluorescent material (abbreviated as HOFs-graft@SP).

[0022] Furthermore, the solvent of the spiropyran solution includes toluene.

[0023] Furthermore, the concentration of the spiropyran solution is 0.1-0.2 mol / L.

[0024] Furthermore, the mass ratio of the spiropyran contained in the spiropyran solution to the naphthalimide-modified HOFs material is 3:5-10.

[0025] Furthermore, the spiropyran is methyl spiropyran (SP-CH3).

[0026] Optionally, the drying is natural drying by standing still.

[0027] The third technical solution of the present invention: an application of the above-mentioned dynamic fluorescent material based on functionalized HOFs in the field of information storage encryption.

[0028] The fourth technical solution of the present invention: an application of the above-mentioned dynamic fluorescent material based on functionalized HOFs in the field of anti-counterfeiting.

[0029] The present invention discloses the following technical effects:

[0030] The present invention introduces naphthalene imide molecules into the HOFs material through an amidation reaction, modifies the free carboxyl groups in the HOFs material, and enhances the stability of the HOFs material. At the same time, due to the fluorescence resonance energy transfer (FRET) effect between the naphthalene imide molecules and the spiropyran molecules under ultraviolet irradiation, the fluorescence color can be changed, so that the system has dynamic fluorescence with time-dependent response, thereby improving the level of information encryption.

[0031] Compared with the unmodified HOFs-loaded spiropyran material, the naphthaleneimide-modified HOFs-loaded spiropyran material prepared by the present invention has better framework stability and dynamic fluorescence color changes, has better development prospects in the field of anti-counterfeiting, and has better information storage encryption functions than most current information storage encryption materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0033] Figure 1 These are the infrared spectra of HOFs materials, HOFs-graft materials and naphthaleneimide.

[0034] Figure 2 These are the infrared spectra of B1-HOF4-SP0.1, B1-HOF4 and methyl spiropyran.

[0035] Figure 3 This is the ultraviolet absorption spectrum of the dynamic fluorescent material B1-HOF4-SP0.1 under 365nm ultraviolet light for different times and the color change diagram of the solid powder after irradiation with 365nm ultraviolet light for different times.

[0036] Figure 4 This is the fluorescence emission spectrum of the dynamic fluorescent material B1-HOF4-SP0.1 under 365nm ultraviolet light for different times and the solid fluorescence color change diagram.

[0037] Figure 5 This is the ultraviolet absorption spectrum of the dynamic fluorescent material B1-HOF4-SP0.2 under 365nm ultraviolet light for different times and the color change diagram of the solid powder after irradiation with 365nm ultraviolet light for different times.

[0038] Figure 6 This is the fluorescence emission spectrum of the dynamic fluorescent material B1-HOF4-SP0.2 under 365nm ultraviolet light for different times and the solid fluorescence color change diagram.

[0039] Figure 7 This is the ultraviolet absorption spectrum of the dynamic fluorescent material B1-HOF5-SP0.1 under 365nm ultraviolet light for different times and the color change diagram of the solid powder after irradiation with 365nm ultraviolet light for different times.

[0040] Figure 8 This is the fluorescence emission spectrum of the dynamic fluorescent material B1-HOF5-SP0.1 under 365nm ultraviolet light for different times and the solid fluorescence color change diagram.

[0041] Figure 9 This is the ultraviolet absorption spectrum of the dynamic fluorescent material B1-HOF5-SP0.2 under 365nm ultraviolet light for different times and the color change diagram of the solid powder after irradiation with 365nm ultraviolet light for different times.

[0042] Figure 10 This is the fluorescence emission spectrum of the dynamic fluorescent material B1-HOF5-SP0.2 under 365nm ultraviolet light for different times and the solid fluorescence color change diagram.

[0043] Figure 11 This is the ultraviolet absorption spectrum of the dynamic fluorescent material C1-HOF4-SP0.1 under 365nm ultraviolet light for different times and the color change diagram of the solid powder after irradiation with 365nm ultraviolet light for different times.

[0044] Figure 12 This is the fluorescence emission spectrum of the dynamic fluorescent material C1-HOF4-SP0.1 under 365nm ultraviolet light for different times and the solid fluorescence color change diagram.

[0045] Figure 13 These are the anti-fatigue performance test results of the dynamic fluorescent material HOFs-graft@SP (specifically B1-HOF5-SP0.2).

[0046] Figure 14 The anti-fatigue performance test results of the dynamic fluorescent material HOF@SP. DETAILED DESCRIPTION

[0047] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0048] It should be understood that the terms described herein are intended only to describe particular embodiments and are not intended to limit the present invention. In addition, for numerical ranges herein, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. The intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also encompassed within the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded within the scope.

[0049] Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of any conflict with any incorporated document, the contents of this specification shall prevail.

[0050] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments described herein without departing from the scope or spirit of the invention. Other embodiments will be apparent to those skilled in the art from the description of the invention. The description and examples are intended to be exemplary only.

[0051] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0052] It should be pointed out that the matters not described in detail in the present invention are conventional operating means in this field and are not the focus of the present invention.

[0053] The room temperature referred to in the present invention is the indoor temperature, which is well known to those skilled in the art and will not be described in detail here; it should be pointed out in particular that the room temperature referred to in the embodiments of the present invention is 25±5°C.

[0054] Unless otherwise specified, all raw materials used in the following examples, comparative examples and test examples of the present invention are common commercially available products.

[0055] Example 1

[0056] A dynamic fluorescent material based on functionalized HOFs is prepared as follows:

[0057] (1) Synthesis of naphthaleneimide molecules

[0058] The reaction route is as follows:

[0059]

[0060] The preparation steps are as follows: 0.59 g of compound 1,8-naphthalene dicarboxylic anhydride (A1) is added to a 100 mL three-necked flask, 50 mL of anhydrous ethanol (ethanol) is added to dissolve it, and 1 mL of compound ethylenediamine (A2) is added. The mixture is evacuated, nitrogen is passed through, and refluxed at 75-80°C for 12 hours. After the reaction is completed, the mixture is cooled to room temperature and the precipitate is filtered. The filtrate is evaporated under reduced pressure and dried in vacuo to obtain compound B, which is naphthalene imide.

[0061] The H NMR spectrum characterization data of compound B is: 1 H-NMR (400MHz, CDCl3): δ1.50(bs,2H,NH2),3.08,(t,2H,CH2,CH2NH2,J=6.6Hz),4.29(t,2H,CH2,CH2N( CO)2),J=6.6Hz),7.75(t,2H,H-Ar,J=7.7Hz),8.21(d,2H,H-Ar,J=8.2Hz),8.59(d,2H,H-Ar,J=7.1Hz).

[0062] (2) Preparation of HOFs-graft materials

[0063] S1. Dissolve 1 g of 2,4,6-tris(4-carboxyphenyl)-1,3,5-triazine (TATB) in 100 mL of N,N-dimethylformamide (DMF). Add 300 mL of deionized water to the solution. Stir at 1000 rpm for 12 h at room temperature, and collect the white solid by centrifugation.

[0064] S2. The collected white solid was washed three times with acetone by centrifugation, then immersed in dichloromethane (CH2Cl2) for three days, and finally centrifuged and vacuum dried to obtain HOFs material.

[0065] S3. Disperse 200 mg of HOFs material in 30 mL of ethanol. Add 50 mg of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) and 50 mg of N-hydroxysuccinimide (NHS) and stir for 30 minutes to activate the carboxyl groups. Collect the white solid by centrifugation, rinse with dichloromethane, and dissolve in 20 mL of dichloromethane. Simultaneously, add 40 or 50 mg of naphthaleneimide molecule B and stir continuously for 8 hours. The final product is collected by centrifugation, rinsed with dichloromethane, and vacuum dried to obtain a white solid, which is the HOFs-graft material. The HOFs-graft material prepared by adding 40 mg of naphthaleneimide molecule B is referred to as B1-HOF5, and the HOFs-graft material prepared by adding 50 mg of naphthaleneimide molecule B is referred to as B1-HOF4.

[0066] Figure 1 The infrared spectra of the HOFs material and HOFs-graft material prepared in step (2) and the naphthaleneimide prepared in step (1) (where HOF represents the unmodified HOFs material, 4:1 represents B1-HOF4, 5:1 represents B1-HOF5, and N represents naphthaleneimide) show that the HOFs material is successfully modified with naphthaleneimide.

[0067] (3) Preparation of HOFs-graft@SP dynamic fluorescent materials

[0068] Take 15 or 30 mg of methyl spiropyran and dissolve it in toluene to prepare a 0.1 mol / L or 0.2 mol / L methyl spiropyran solution. Use a dropper to evenly drop the prepared methyl spiropyran solution onto 50 mg of The HOFs-graft material (B1-HOF4 or B1-HOF5) was left to stand at room temperature for 3 hours and dried naturally to obtain the HOFs-graft@SP dynamic fluorescent material, wherein the product prepared using a 0.1 mol / L methyl spiropyran solution and B1-HOF4 was recorded as B1-HOF4-SP0.1, the product prepared using a 0.2 mol / L methyl spiropyran solution and B1-HOF4 was recorded as B1-HOF4-SP0.2, the product prepared using a 0.1 mol / L methyl spiropyran solution and B1-HOF5 was recorded as B1-HOF5-SP0.1, and the product prepared using a 0.2 mol / L methyl spiropyran solution and B1-HOF5 was recorded as B1-HOF5-SP0.2.

[0069] Figure 2 The infrared spectra of B1-HOF4-SP0.1 prepared in step (3), B1-HOF4 prepared in step (2) and methyl spiropyran (HOF-G represents B1-HOF4, HOF-G@SP represents B1-HOF4-SP0.1, and SP-CH3 represents methyl spiropyran) are shown in the figure. The characteristic peak of SP (1336 cm -1 The stretching vibration peak of -NO2 is 1091cm -1 The peak at the center is the stretching vibration peak of the CO bond), indicating that SP was successfully loaded into the functionalized HOFs.

[0070] Comparative Example 1

[0071] The steps for preparing HOFs@SP materials are as follows:

[0072] S1. Dissolve 1 g of 2,4,6-tris(4-carboxyphenyl)-1,3,5-triazine (TATB) in 100 mL of N,N-dimethylformamide (DMF). Add 300 mL of deionized water to the solution. Stir at 1000 rpm for 12 h at room temperature, and collect the white solid by centrifugation.

[0073] S2. The collected white solid was washed three times with acetone by centrifugation, then immersed in dichloromethane (CH2Cl2) for three days, and finally centrifuged and vacuum dried to obtain HOFs material.

[0074] S3. Take 30 mg of methyl spiropyran and dissolve it in toluene to prepare a methyl spiropyran solution with a concentration of 0.2 mol / L. Use a dropper to evenly add all of it to 50 mg of HOFs material. Let it stand at room temperature for 3 hours and dry naturally to obtain HOFs@SP material.

[0075] Comparative Example 2

[0076] Preparation of HOFs-graft(NG)@SP material, the steps are as follows:

[0077] (1) Synthesis of naphthaleneimide molecules

[0078] In a 100 mL three-necked flask, 0.59 g of the compound 6-(dimethylamino)-1H,3H-benzo[de]isochromene-1,3-dione was added, 50 mL of anhydrous ethanol was added to dissolve, and 1 mL of the compound ethylenediamine was added. The mixture was vacuumed, nitrogen was passed through, and the mixture was refluxed at 75-80 ° C for 12 h. After the reaction was completed, the mixture was cooled to room temperature and the precipitate was filtered. The filtrate was evaporated under reduced pressure and dried in vacuum to obtain the naphthalene imide molecule C (structural formula: ).

[0079] (2) Preparation of HOFs-graft (NG) materials

[0080] S1. Dissolve 1 g of 2,4,6-tris(4-carboxyphenyl)-1,3,5-triazine (TATB) in 100 mL of N,N-dimethylformamide (DMF). Add 300 mL of deionized water to the solution. Stir at 1000 rpm for 12 h at room temperature, and collect the white solid by centrifugation.

[0081] S2. The collected white solid was washed three times with acetone by centrifugation, then immersed in dichloromethane (CH2Cl2) for three days, and finally centrifuged and vacuum dried to obtain HOFs material.

[0082] S3. Disperse 200 mg of HOFs material in 30 mL of ethanol. Add 50 mg of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) and 50 mg of N-hydroxysuccinimide (NHS) and stir for 30 minutes to activate the carboxyl groups. Collect the white solid by centrifugation, rinse with dichloromethane, and dissolve in 20 mL of dichloromethane. Add 50 mg of naphthaleneimide molecule C and stir continuously for 8 hours. The final product is collected by centrifugation, rinsed with dichloromethane, and vacuum dried to obtain a white solid, which is the HOFs-graft (NG) material, referred to as C1-HOF4.

[0083] (3) Preparation of HOFs-graft(NG)@SP materials

[0084] 15 mg of methyl spiropyran was dissolved in toluene to prepare a methyl spiropyran solution with a concentration of 0.1 mol / L. The prepared methyl spiropyran solution was evenly added to 50 mg of HOFs-graft (NG) material (C1-HOF4) using a dropper. The solution was allowed to stand at room temperature for 3 h and dried naturally to obtain the HOFs-graft (NG)@SP dynamic fluorescent material, which was recorded as C1-HOF4-SP0.1.

[0085] Test Example 1

[0086] Figure 3 This is the ultraviolet absorption spectrum of the dynamic fluorescent material B1-HOF4-SP0.1 prepared in Example 1 under 365nm ultraviolet light irradiation for different times and the color change diagram of the solid powder after irradiation with 365nm ultraviolet light for different times.

[0087] Figure 4 This is the fluorescence emission spectrum and solid fluorescence color change diagram of the dynamic fluorescent material B1-HOF4-SP0.1 prepared in Example 1 under 365nm ultraviolet light irradiation for different times.

[0088] Figure 5 This is the ultraviolet absorption spectrum of the dynamic fluorescent material B1-HOF4-SP0.2 prepared in Example 1 under 365nm ultraviolet light irradiation for different times and the color change diagram of the solid powder after irradiation with 365nm ultraviolet light for different times.

[0089] Figure 6 This is the fluorescence emission spectrum and solid fluorescence color change diagram of the dynamic fluorescent material B1-HOF4-SP0.2 prepared in Example 1 under 365nm ultraviolet light irradiation for different times.

[0090] Figure 7 This is the ultraviolet absorption spectrum of the dynamic fluorescent material B1-HOF5-SP0.1 prepared in Example 1 under 365nm ultraviolet light irradiation for different times and the color change diagram of the solid powder after irradiation with 365nm ultraviolet light for different times.

[0091] Figure 8 This is the fluorescence emission spectrum and solid fluorescence color change diagram of the dynamic fluorescent material B1-HOF5-SP0.1 prepared in Example 1 under 365nm ultraviolet light irradiation for different times.

[0092] Figure 9 This is the ultraviolet absorption spectrum of the dynamic fluorescent material B1-HOF5-SP0.2 prepared in Example 1 under 365nm ultraviolet light irradiation for different times and the color change diagram of the solid powder after irradiation with 365nm ultraviolet light for different times.

[0093] Figure 10This is the fluorescence emission spectrum and solid fluorescence color change diagram of the dynamic fluorescent material B1-HOF5-SP0.2 prepared in Example 1 under 365nm ultraviolet light irradiation for different times.

[0094] Figure 11 This is the ultraviolet absorption spectrum of the dynamic fluorescent material C1-HOF4-SP0.1 prepared in Comparative Example 2 under 365nm ultraviolet light irradiation for different times and the color change diagram of the solid powder after irradiation with 365nm ultraviolet light for different times.

[0095] Figure 12 This is the fluorescence emission spectrum and solid fluorescence color change diagram of the dynamic fluorescent material C1-HOF4-SP0.1 prepared in Comparative Example 2 under 365nm ultraviolet light irradiation for different times.

[0096] Fluorescence emission spectrum of the dynamic fluorescent material prepared in Example 1 ( Figure 4 、 Figure 6 、 Figure 8 and Figure 10 , excitation wavelength: 365nm) it can be seen that after ultraviolet irradiation, the spectrum shows a characteristic peak of naphthalimide molecule B at 460nm, and the solid powder shows blue fluorescence; with different irradiation times, the characteristic emission peak of naphthalimide molecule B at 460nm decreases to varying degrees, indicating that under ultraviolet irradiation, obvious energy resonance transfer occurs between naphthalimide molecules and spiropyran, realizing a variety of dynamic fluorescence color responses of the material. Figures 3 to 10 The fluorescence and actual color change diagram of the dynamic fluorescent material prepared in Comparative Example 2 ( Figures 11 to 12 )and Figures 3 to 10 By comparison, it can be found that the fluorescence and actual color changes of the dynamic fluorescent material prepared in Comparative Example 2 are not as obvious as those in Example 1, which is not ideal for information encryption applications. This also shows that the structure of the naphthalimide molecule affects the performance of the dynamic fluorescent material.

[0097] Specifically, the dynamic fluorescent material based on functionalized HOFs with the component B1-HOF4-SP0.1 prepared in Example 1 of the present invention has a significant change in the maximum fluorescence intensity (reduced by 1.176×10 5 CPS), the fluorescence color changed significantly at 20s, from blue to cyan, and as time went on, the fluorescence color turned to purple, which was more different from blue, and at 600s it turned to deep purple, which was very different from blue (such as Figure 4As shown). At 20s, the absorbance also changed significantly (the absorbance at 550nm increased from 0.244 to 0.26). At 30s, the color of the solid powder changed significantly, from brown-gray to flesh-pink. As time went on, the color of the solid powder turned to purple, which was more different from the brown-gray. At 600s, the color of the solid powder turned to dark purple, which was very different from the brown-gray (as shown). Figure 3 This indicates that the dynamic fluorescent material based on functionalized HOFs prepared by the present invention has dynamic fluorescence changes in a time-dependent manner.

[0098] The dynamic fluorescent material based on functionalized HOFs with the component B1-HOF4-SP0.2 prepared in Example 1 of the present invention has a significant change in the maximum fluorescence intensity (reduced by 1.5×10 4 CPS), the fluorescence color changed significantly at 10s, from blue to cyan, and as time went on, the fluorescence color turned to purple, which was more different from blue, and at 180s it turned to deep purple, which was very different from blue (such as Figure 6 As shown). At 10s, the absorbance also changed significantly (the absorbance at 550nm increased from 0.25 to 0.30). At 30s, the color of the solid powder changed significantly, from brown-gray to flesh-pink. As time went on, the color of the solid powder turned to purple, which was more different from the brown-gray. At 180s, the color of the solid powder turned to dark purple, which was very different from the brown-gray (as shown). Figure 5 This indicates that the dynamic fluorescent material based on functionalized HOFs prepared by the present invention has time-dependent dynamic fluorescence changes and a fast response speed.

[0099] The dynamic fluorescent material based on functionalized HOFs with the component B1-HOF5-SP0.1 prepared in Example 1 of the present invention has a significant change in the maximum fluorescence intensity (reduced by 2.24×10 4 CPS), the fluorescence color changed significantly at 30s, from blue to light purple, and as time went on, the fluorescence color changed to a color that was more different from blue, and at 300s it turned into a rose red that was very different from blue (such as Figure 8 As shown). At 5s, the absorbance also changed significantly (the absorbance at 550nm increased from 0.16 to 0.30). At 30s, the color of the solid powder changed significantly, from brown-gray to flesh-purple. As time went on, the color of the solid powder changed to a color that was more different from the brown-gray. At 300s, the color of the solid powder turned to a dark pink that was very different from the brown-gray (as shown). Figure 7This indicates that the dynamic fluorescent material based on functionalized HOFs prepared by the present invention has time-dependent dynamic fluorescence changes and a fast response speed.

[0100] The dynamic fluorescent material based on functionalized HOFs with the component B1-HOF5-SP0.2 prepared in Example 1 of the present invention has a significant change in the maximum fluorescence intensity (reduced by 2.6×10 4 CPS), the fluorescent color also changed significantly, from blue to dark pink, and as time went on, the fluorescent color changed to a color that was more different from blue, and at 300s it turned into a rose red that was very different from blue (such as Figure 10 As shown). At 5s, the absorbance also changed significantly (the absorbance at 550nm increased from 0.16 to 0.26). At 30s, the color of the solid powder changed significantly, from brown-gray to light pink. As time went on, the color of the solid powder changed to a color that was more different from the brown-gray. At 300s, the color of the solid powder turned to a dark pink that was very different from the brown-gray (as shown). Figure 9 This indicates that the dynamic fluorescent material based on the functionalized HOF prepared by the present invention has a time-dependent dynamic fluorescence change and a fast response speed.

[0101] The dynamic fluorescent material based on functionalized HOFs with the component C1-HOF4-SP0.1 prepared in Comparative Example 2 of the present invention has a solid powder that, when irradiated with ultraviolet light at a wavelength of 365 nm, shows a slight change in the fluorescent color and the solid powder color after 60 seconds, but the change is not significant. As time goes by, although the fluorescent color and the solid powder color continue to change, even the color change at 180 seconds is far less obvious than that of the dynamic fluorescent material in Example 1.

[0102] Test Example 2

[0103] Fatigue resistance test

[0104] Test Method: Because dynamic fluorescent materials change color and fluorescence under UV light and return to their original color under white light, they were alternately irradiated with UV and white light (UV exposure for 300 seconds and white light exposure for 1 hour) and their UV absorbance was measured to characterize their light fatigue resistance.

[0105] Figure 13 The fatigue resistance test results of the dynamic fluorescent material HOFs-graft@SP (specifically B1-HOF5-SP0.2) prepared in Example 1 are as follows: Figure 14The anti-fatigue performance test results of the dynamic fluorescent material HOF@SP prepared in Comparative Example 1 (the pink dots represent ultraviolet light irradiation, and the rose-red dots represent white light irradiation) show that after 10 cycles, the performance of HOFs-graft@SP is better than that of HOFs@SP, indicating that HOFs-graft@SP has better anti-fatigue performance.

[0106] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A dynamic fluorescent material based on functionalized HOFs, characterized in that: The dynamic fluorescent material based on functionalized HOFs is a HOF material modified by naphthaleneimide loaded with spiropyran.

2. The dynamic fluorescent material based on functionalized HOFs according to claim 1, characterized in that: The preparation step of the naphthalimide-modified HOFs material comprises: modifying the surface of the HOFs material activated by a catalyst with naphthalimide through an amidation reaction to obtain the naphthalimide-modified HOFs material.

3. The dynamic fluorescent material based on functionalized HOFs according to claim 2, characterized in that: The structural formula of the naphthalene imide is 4. The dynamic fluorescent material based on functionalized HOFs according to claim 3, characterized in that: The naphthaleneimide is obtained by amidation reaction of 1,8-naphthalene dicarboxylic anhydride and ethylenediamine.

5. The dynamic fluorescent material based on functionalized HOFs according to claim 2, characterized in that: The catalyst includes 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and N-hydroxysuccinimide.

6. The dynamic fluorescent material based on functionalized HOFs according to claim 2, characterized in that: The mass ratio of the naphthalimide to the HOFs material is 1:4-5.

7. A method for preparing a dynamic fluorescent material based on functionalized HOFs according to any one of claims 1 to 6, characterized in that: The following steps are involved: The spiropyran solution is added dropwise to the HOFs material modified with naphthalimide, and the mixture is dried to obtain the functionalized HOFs-based dynamic fluorescent material.

8. The preparation method according to claim 7, wherein The solvent of the spiropyran solution includes toluene; and / or, the concentration of the spiropyran solution is 0.1-0.2 mol / L; And / or, the mass ratio of the spiropyran contained in the spiropyran solution to the naphthalimide-modified HOFs material is 3:5-10.

9. Use of the dynamic fluorescent material based on functionalized HOFs according to any one of claims 1 to 6 in the field of information storage and encryption.

10. Use of the dynamic fluorescent material based on functionalized HOFs according to any one of claims 1 to 6 in the field of anti-counterfeiting.

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