Diaryl ethylene compound, nano fluorescent dye, preparation method of diaryl ethylene compound and nano fluorescent dye, and application of diaryl ethylene compound and nano fluorescent dye in anti-counterfeiting field

Abstract

The invention belongs to the technical field of synthesis and application of photochromic materials, and particularly relates to a diarylethene compound, a nano fluorescent dye, a preparation method of the diarylethene compound and the nano fluorescent dye and application of the diarylethene compound and the nano fluorescent dye in the anti-counterfeiting field. According to the invention, 2-methylbenzothiophene is prepared into a fluorescence opening type diarylethene molecule through a classical synthesis route, and then the molecule is used for preparing the nano fluorescent dye. The diarylethene nano fluorescent dye prepared by the invention has good thermal stability and dynamic fluorescent anti-counterfeiting characteristic, combines the characteristics of photochromism and fluorescent imaging, simply and effectively prepares dynamic fluorescent anti-counterfeiting patterns and two-dimensional codes, and has the advantages of high anti-counterfeiting sensitivity, simplicity and convenience in operation, strong repeatability and the like. The application of diarylethene in the field of fluorescent falsification prevention is verified, and a thought is provided for design and modification of the multifunctional fluorescent nano dye.

Description

Technical Field

[0001] This invention belongs to the field of synthesis and application technology of photochromic materials, specifically relating to a diarylethylene compound and a nano-fluorescent dye, their preparation method, and their application in the field of anti-counterfeiting. Background Technology

[0002] Counterfeit and substandard goods are a growing global problem, not only infringing on consumers' legitimate rights and interests but also seriously affecting the effective use of social resources. Therefore, developing new anti-counterfeiting materials and technologies to establish a robust and insurmountable technological barrier for counterfeiters has become an effective and practical approach. Among numerous anti-counterfeiting technologies (cryptographic technology, RFID technology, holographic anti-counterfeiting technology, fluorescent anti-counterfeiting technology, etc.), fluorescent anti-counterfeiting has attracted widespread attention from researchers due to its advantages such as low cost, ease of operation, high level of concealment and encryption, multiple emission colors, and universal applicability to the public.

[0003] Traditional fluorescent anti-counterfeiting technology relies on the static fluorescence of fluorescent materials; the pattern with the information written on it displays a bright and vivid fluorescent pattern under ultraviolet or infrared light. However, with the widespread application of fluorescent anti-counterfeiting technology and the reduction in production costs, these fluorescent patterns are easily cloned and imitated using commercially available fluorescent dyes, leading to rampant counterfeiting and making counterfeit identification a prominent problem. Therefore, there is an urgent need to develop new anti-counterfeiting materials with dynamic fluorescence, whose fluorescence color and intensity change dynamically under external stimuli (light, heat, electricity, etc.). The added dynamic function acts like a "key" that can trigger fluorescence in specific scenarios, greatly enhancing security and increasing the difficulty of counterfeiting. Among them, light-driven fluorescent dyes are ideal for constructing dynamic fluorescent patterns due to their tunable fluorescence color, intensity, and good reversibility; furthermore, nanoscale (<500nm) dyes can be used in printing processes to obtain personalized fluorescent anti-counterfeiting devices.

[0004] Diarylethylene photochromic fluorescent dyes possess excellent photostability, fatigue resistance, high fluorescence quantum efficiency, and photochromic properties, making them a good choice for constructing light-driven fluorescent nanodyes. Summary of the Invention

[0005] In view of the problems and shortcomings of the existing technology, the purpose of this invention is to provide a diarylethylene compound and a nano-fluorescent dye, a method for preparing the same, and its application in the field of anti-counterfeiting.

[0006] To achieve the objectives of this invention, the technical solution adopted is as follows:

[0007] The first aspect of this invention provides a diarylethene compound, the structural formula of which is shown in Formula 1:

[0008]

[0009] R1 and R2 are both selected from hydrogen atoms or trimethylsilyl ethynyl groups.

[0010] According to the above-mentioned diarylethylene compounds, preferably, R1 is trimethylsilylethynyl and R2 is selected from hydrogen atoms or trimethylsilylethynyl.

[0011] The second aspect of the present invention provides a method for preparing the above-mentioned diarylethene compounds, comprising the following steps: adding m-chloroperoxybenzoic acid to a solution of compound E under an ice-water bath and reacting overnight; quenching the reaction, extracting the reaction solution with an organic solvent, collecting the organic phase and removing the organic solvent to obtain a crude product; and after separation and purification of the crude product, obtaining a diarylethene compound with the structural formula shown in Formula 1.

[0012] The structural formula of compound E is shown in formula e:

[0013]

[0014] R1 and R2 are both selected from hydrogen atoms or trimethylsilyl ethynyl groups.

[0015] According to the above-mentioned method for preparing a diarylethylene compound, preferably, in the structural formula of compound E, R1 is trimethylsilylethynyl and R2 is selected from hydrogen atom or trimethylsilylethynyl.

[0016] According to the above-mentioned method for preparing a diarylethene compound, preferably, the molar ratio of compound E to m-chloroperoxybenzoic acid is 1:5 to 10.

[0017] More preferably, according to the above-mentioned method for preparing a diarylethylene compound, the solvent in the solution of compound E is dichloromethane, and the organic solvent used for extraction is dichloromethane; the crude product separation and purification process is as follows: the crude product is purified by silica gel column chromatography, eluted with petroleum ether: dichloromethane = 1:1, the eluent is collected, and the solvent is removed by vacuum evaporation of the eluent to obtain a diarylethylene compound with the structural formula shown in Formula 1.

[0018] According to the above-mentioned method for preparing a diarylethylene compound, preferably, the method for preparing compound E includes: adding bis(triphenylphosphine)palladium dichloride, cuprous iodide, and trimethylsilylacetylene to a solution of compound D under an inert gas atmosphere, and heating at 60–80°C for 10–20 h; after the reaction is completed, adding water to the reaction solution, then extracting with an organic solvent, collecting the organic phase and removing the organic solvent from the organic phase to obtain a crude product; the crude product is purified to obtain compound E; the structural formula of compound D is shown in formula d:

[0019]

[0020] R1 and R2 are both selected from hydrogen atoms or iodine atoms.

[0021] According to the above-mentioned method for preparing a diarylethylene compound, more preferably, in the structural formula of compound D, R1 is trimethylsilylethynyl and R2 is selected from hydrogen atom or trimethylsilylethynyl.

[0022] More preferably, according to the above-mentioned method for preparing a diarylethene compound, the molar ratio of compound D to trimethylsilylacetylene is 1:1.4-1.6.

[0023] More preferably, according to the above-mentioned method for preparing a diarylethylene compound, the solvent in the solution of compound D is triethylamine, and the organic solvent used for extraction is dichloromethane; the separation and purification process of the crude product is as follows: the crude product is purified by silica gel column chromatography, eluted with pure petroleum ether, the eluent is collected, and the solvent is removed by vacuum evaporation of the eluent to obtain compound E.

[0024] According to the above-mentioned method for preparing a diarylethylene compound, preferably, the method for preparing compound D includes the following steps: dissolving compound C in solvent E, adding sulfuric acid, iodine and periodic acid; stirring at 60-80°C for 2-4 hours, then pouring the reaction solution into water to obtain a mixture; adding a saturated sodium bicarbonate solution to the mixture, then extracting with ethyl acetate, separating the liquid, washing the organic phase with sodium thiosulfate, filtering, collecting the filtrate, and removing the solvent from the filtrate to obtain compound D;

[0025] The structural formula of compound C is shown in formula c:

[0026]

[0027] More preferably, according to the above-described method for preparing a diarylethylene compound, the solvent E is acetic acid.

[0028] According to the above-mentioned method for preparing a diarylethylene compound, preferably, the method for preparing compound C includes the following steps: under an inert gas atmosphere, compound A is dissolved in solvent F, and then n-butyllithium is slowly added at -60 to -80°C. After stirring for 0.5 to 1 hour, compound B is added dropwise. After the temperature returns to room temperature, the reaction is stirred. The reaction is quenched, the reaction solution is extracted with ethyl acetate, the organic phase is collected, and the solvent is removed to obtain compound C.

[0029] The structural formulas of compounds A and B are shown in formulas a and b:

[0030]

[0031] A fourth aspect of the present invention provides a nano-fluorescent dye, wherein the nano-fluorescent dye comprises the diarylethylene compounds described in the first aspect of the present invention.

[0032] According to the above-mentioned nano-fluorescent dye, preferably, the nano-fluorescent dye is a nano-fluorescent dye prepared from the diarylethylene compounds described in the first aspect of the present invention.

[0033] According to the above-mentioned nanofluorescent dye, preferably, the structural formula of the diarylethene compound is shown in Formula 1-1 or Formula 1-2:

[0034]

[0035] According to the above-mentioned nano-fluorescent dye, preferably, the nano-fluorescent dye is a fluorescent anti-counterfeiting pattern or fluorescent anti-counterfeiting QR code made of diarylethene compounds.

[0036] More preferably, according to the above-mentioned nano-fluorescent dye, the nano-fluorescent dye is in a concealed state under ordinary light, and exhibits a fluorescent effect under specific light irradiation.

[0037] More preferably, according to the above-mentioned nano-fluorescent dye, the nano-fluorescent dye is in a concealed state under ordinary light and exhibits green fluorescence under 365nm wavelength light.

[0038] Furthermore, the above-mentioned nano-fluorescent dyes are applied in the field of anti-counterfeiting.

[0039] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0040] 1. This invention successfully prepared diarylethene compounds, the main body of which consisted of a vinyl group, a perfluorocyclopentene, and two benzothiophenes. Different substituents were introduced on both sides of the benzothiophenes to change the packing mode and electron delocalization of the compound, thereby making the compound exhibit strong fatigue resistance. The oxidation of sulfur on the thiophene ring to sulfone through a simple oxidation reaction can significantly improve the fluorescence quantum yield. This invention has guiding significance for the study of the effects of different substituents on the properties of diarylethene.

[0041] 2. The diarylene ethylene photochromic nanofluorescent dye prepared by this invention has excellent fatigue resistance and thermal stability, and achieves high-resolution light-driven dynamic fluorescence anti-counterfeiting under ultraviolet and visible light irradiation, providing guidance for the design and application of dynamic nanofluorescent dyes. Attached Figure Description

[0042] Figure 1 The 1H NMR spectrum of compound C of this invention;

[0043] Figure 2The 1H NMR spectrum of compound E (structural formula e-1) of this invention;

[0044] Figure 3 The 1H NMR spectrum of compound E (structural formula e-2) of this invention;

[0045] Figure 4 The 1H NMR spectrum of the diarylethylene compounds (structural formula 1-1) of this invention;

[0046] Figure 5 The 1H NMR spectra of the diarylethylene compounds (structural formulas 1-2) of this invention are shown below.

[0047] Figure 6 This is the UV-absorbing spectrum of the closed / open ring isomers of the diarylethene compound BTF6O4Si of this invention;

[0048] Figure 7 The diagram shows the color and fluorescence changes of the closed-ring / open-ring isomer solution of the compound BTF6O4Si before and after irradiation with a 365nm ultraviolet light source.

[0049] Figure 8 The fluorescence spectra of the closed-ring isomer of the diarylethene compound BTF6O4Si of this invention with different UV irradiation times;

[0050] Figure 9 This is a scanning electron microscope image of the diarylethylene fluorescent nanodye of the present invention;

[0051] Figure 10 The ultraviolet-visible absorption spectrum of the diarylethylene fluorescent nanodye of this invention;

[0052] Figure 11 This is a graph showing the color and fluorescence changes of the closed-ring / open-ring diarylethylene nanofluorescent dye of the present invention under 365nm ultraviolet light irradiation;

[0053] Figure 12 The fluorescence spectrum of the ring-opening diarylethylene nanofluorescent dye of this invention;

[0054] Figure 13 The fluorescence spectrum of the closed-ring diarylethylene nanofluorescent dye of this invention;

[0055] Figure 14 The images show the color and fluorescence of the open-ring nanofluorescent dye of this invention under ultraviolet light and visible light in its aggregated state.

[0056] Figure 15 The images show the color and fluorescence of the closed-loop nano-fluorescent dye in its aggregated state under ultraviolet light and visible light.

[0057] Figure 16This is a color comparison image of the anti-counterfeiting pattern of the present invention before and after irradiation with ultraviolet light and visible light;

[0058] Figure 17 This is a color comparison image of the anti-counterfeiting QR code of this invention before and after irradiation with ultraviolet light and visible light. Detailed Implementation

[0059] The following embodiments are only for further elaboration of the present invention. It should be noted that all techniques and scientific terms used in this invention, unless otherwise stated, have the same meaning as those in the technical field to which this invention pertains. Experimental methods in the following embodiments that do not specify specific conditions all employ conventional techniques in this technical field or follow the conditions recommended by the manufacturer; reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0060] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments.

[0061] Example 1

[0062] A compound C with the structural formula shown in formula c is prepared by the following steps:

[0063] At -78°C, 41 mL (66 mmol) of n-butyllithium was slowly added to 10 g (44 mmol) of anhydrous tetrahydrofuran (100 mL) containing compound A (2-Methyl-1-thiaindene, CAS: 1195-14-8). After 1 hour, 2.95 mL (22 mmol) of compound B (perfluorocyclopentene, CAS: 559-40-4) was slowly added dropwise to obtain the reaction solution. The reaction solution was then brought to room temperature and stirred for 12 hours. After the reaction was completed, a saturated ammonium chloride aqueous solution was added to the reaction solution, and then extracted with dichloromethane. The organic phase was collected, dried with anhydrous sodium sulfate, filtered, and the filtrate was collected. The filtrate was then purified by silica gel column chromatography (eluting with pure petroleum ether). The eluent was collected, and the solvent was removed by vacuum evaporation to obtain compound C (the substance name is 1,2-Bis(2-methylbenzo[b]thiophen-3-yl)hexafluorocyclopentene, CAS:137814-07-4). The yield of compound C was 47%.

[0064] The structural formula of compound C is as follows:

[0065]

[0066] The specific reaction equation is as follows:

[0067]

[0068] NMR analysis was performed on the prepared compound C (NMR results are shown in the figure). Figure 1 As shown in the figure: ¹H NMR (300MHz, CDCl₃) δ 7.22–7.58 (m, 4H), 7.42–7.16 (m, 4H), 2.52 (s, 6H × 0.36, p), 2.25 (s, 6H × 0.64, ap). The above results confirm that the obtained product is the target product.

[0069] Example 2

[0070] A compound D with the structural formulas shown in formulas d-1 and d-2 is prepared as follows:

[0071] 2.65 g (5.66 mmol) of compound C was dissolved in 200 mL of acetic acid (containing 9.4 mL of water), and then sulfuric acid (4 mL), 1.72 g (6.79 mmol) of iodine and 554 mg (2.43 mmol) of periodic acid were added. The mixture was stirred at 70 °C for 3 h. After the reaction was completed, 500 mL of saturated sodium bicarbonate solution was added to the reaction solution, and then extracted with ethyl acetate. The organic phase was collected and dried with anhydrous sodium sulfate. The dried organic phase was then purified by silica gel column chromatography (eluting with pure petroleum ether). The eluent was collected and the solvent was removed by vacuum evaporation to obtain compound D with the structural formula shown in formula d-1 (substance name: 3-[3,3,4,4,5,5-Hexafluoro-2-(2-methylbenzo[b]thien-3-yl)-1-cyclopenten-1-yl]-6-iodo-2-ethylbenzo[b]thiophene, CAS: 364050-44-2) and compound D with the structural formula shown in formula d-2 (substance name: 3,3′-(3,3,4,4,5,5-Hexafluoro-1-cyclopentene-1,2-diyl)bis[6-iodo-2-methylbenzo[b]thiophene], CAS: 167890-07-5).

[0072] The structural formula of compound D is as follows:

[0073]

[0074] The specific reaction equation is as follows:

[0075]

[0076] Example 3

[0077] A compound E with the structural formulas shown in formula e-1 and e-2 is prepared as follows:

[0078] Under a nitrogen atmosphere, compounds D (760 mg in total, of which md-1 / md-2 = 33 / 67), 137 mg (0.195 mmol) of bis(triphenylphosphine)palladium dichloride, 411 mg (2.16 mmol) of cuprous iodide, and 1.42 g (2.16 mmol) of trimethylethynylsilane were dissolved in 11 mL of triethylamine and reacted with stirring at 80 °C for 15 h. After the reaction was completed, 10 mL of water was added to the reaction solution, and then the solution was extracted with dichloromethane. The organic phase was collected and dried. The dried organic phase was then purified by silica gel column chromatography (eluting with pure petroleum ether). The eluent was collected and the solvent was removed by vacuum evaporation to obtain compound E with structural formula as shown in e-1 (yield 95%, CAS: 2448126-43-8) and compound E with structural formula as shown in e-2 (yield 91%, CAS: 2448126-44-9).

[0079] The structural formula of compound E is as follows:

[0080]

[0081] The specific reaction equation is as follows:

[0082]

[0083] NMR analysis was performed on compound E, whose structural formula is shown in formula e-1 (NMR results are shown in the figure). Figure 2 As shown: ¹H NMR (300MHz, CDCl₃) δ 7.83–7.19 (m, 7H), 2.49 (s, 6H × 0.38, p), 2.23 (s, 3H × 0.62, ap), 2.22 (s, 3H × 0.62, ap), 0.30 (s, 9H × 0.62, ap), 0.27 (s, 9H × 0.38, p). These results confirm that the obtained product is the target product.

[0084] NMR analysis was performed on compound E, whose structural formula is shown in formula e-2 (NMR results are shown in the figure). Figure 3(As shown): 1H NMR (300MHz, CDCl3) δ 7.81 (s, 2H×0.59, ap), 7.73 (s, 2H×0.41, p), 7.53 (d, 2H×0.59, ap), 7.74–7.38 (m, 2H), 7.24 (s, 2H×0.41, p), 2.46 (s, 6H×0.41, p), 2.18 (s, 6H×0.59, ap), 0.26 (s, 18H×0.59, ap), 0.24 (m, 18H×0.41, p).

[0085] Example 4

[0086] A diarylethylene compound with the structural formulas shown in Formulas 1-1 and 1-2 is prepared as follows:

[0087] Under ice-water bath conditions, 400 mg of compound E, with structural formula e-1, was dissolved in 20 mL of dichloromethane. 1.22 g (7.08 mmol) of m-chloroperoxybenzoic acid was slowly added to the mixture, and the mixture was allowed to slowly return to room temperature for 24 h. After the reaction was complete, a 10% sodium thiosulfate and sodium bicarbonate solution was added to the reaction solution, and the mixture was separated. The solution was extracted with dichloromethane, filtered, and the filtrate was collected. The filtrate was then purified by silica gel column chromatography using petroleum ether:dichloromethane in a 1:1 ratio. The eluent was collected, and the solvent was removed by vacuum evaporation to obtain diarylethene compounds with structural formula 1-1. The yield of diarylethene compounds with structural formula 1-1 was 89%.

[0088]

[0089] The specific reaction equation is as follows:

[0090]

[0091] Nuclear magnetic resonance (NMR) analysis was performed on the prepared diarylethene compounds with the structural formula shown in Formula 1-1 (NMR results are shown in the figure). Figure 4 As shown in the figure: 1H NMR (300MHz, CDCl3) δ 7.73-7.709 (s, 1H×0.38, p), 7.49 (m, 1H), 7.19 (s, 1H×0.38, p), 6.96 (m, 2H), 2.17-2.02 (t, 6H), 1.30-1.19 (m, 8H). The above results confirm that the obtained product is the target product.

[0092] Example 5

[0093] A diarylethylene compound with the structural formula shown in Formula 1-2 was prepared in a manner that was basically the same as in Example 4, except that the structural formula of compound E was shown in Formula e-2, the amount of m-chloroperoxybenzoic acid used was 1.04 g (6.05 mmol), and the yield of the diarylethylene compound with the structural formula shown in Formula 1-2 was 85%.

[0094]

[0095] NMR analysis was performed on compounds 1-2 (NMR results are shown in the figure). Figure 5 As shown in the figure: 1H NMR (300MHz, CDCl3) δ 7.84-7.80 (d, 2H), 7.66-7.44 (d, 1H×0.38, p), 7.50-7.48 (d, 2H×0.62, ap), 7.09-7.04 (t, 2H×0.62, ap), 2.21-2.06 (d, 6H×0.62, ap), 0.32-0.38 (m, 18H×0.38, p). The above results confirm that the obtained product is the target product.

[0096] Example 6

[0097] The preparation method of the diarylethylene nanofluorescent dye is as follows: the diarylethylene compound prepared in Example 4 or Example 5 is mixed with water and ethanol, and self-assembled. The mixture is then left to stand in a beaker for a period of time to form nanoparticles, thus preparing the diarylethylene nanofluorescent dye.

[0098] Performance characterization of the diarylethene compounds and diarylethene nanofluorescent dyes prepared in this invention

[0099] The two diarylethene compounds prepared in Examples 4 and 5 of this invention are named BTF6O4Si (structural formula 1-1) and BTF6O4Si2 (structural formula 1-2), respectively. Since BTF6O4Si and BTF6O4Si2 have similar properties, this invention only demonstrates the performance characterization of BTF6O4Si.

[0100] (I) Characterization of the diarylethylene compound BTF6O4Si

[0101] (1) Ultraviolet-absorption spectroscopy characterization

[0102] The diarylethene compound BTF6O4Si prepared in Example 4 of this invention was dissolved in ethanol and subjected to ultraviolet-absorption spectroscopy. The results are as follows: Figure 6 As shown. From Figure 6It can be seen that before ultraviolet light irradiation, the open-ring isomer of BTF6O4Si exhibits a broad absorption band centered at 224 nm. After irradiation with 365 nm ultraviolet light, BTF6O4Si shows a new broad absorption band between 390 and 490 nm, indicating that the open-ring isomer of BTF6O4Si undergoes photocyclization to form a closed morphology. BTF6O4Si reaches photostable state after 10 minutes of ultraviolet light irradiation. However, when exposed to visible light above 490 nm, BTF6O4Si undergoes a cyclization reaction, returning to the open-ring state and reproducing the original absorption spectrum. Figure 7 The image shows the color and fluorescence changes of solutions of the closed-ring / open-ring isomers of compound BTF6O4Si before and after irradiation with a 365 nm ultraviolet light source. Figure 7 As can be seen on the left, under ultraviolet irradiation, the closed-ring isomer solution emits green fluorescence, while the open-ring isomer solution is colorless and transparent. Figure 7 As can be seen on the right, when exposed to sunlight, the closed-ring isomer solution appears yellow, while the open-ring isomer solution is colorless and transparent.

[0103] (2) Fluorescence spectroscopy characterization

[0104] The fluorescence emission of the closed-ring isomer of the diarylethene compound BTF6O4Si was measured with varying UV irradiation times, and the results are as follows: Figure 8 As shown. Figure 8 The results showed that BTF6O4Si exhibited a broad emission spectrum at room temperature, with the emission peak located at 500 nm. With increasing UV irradiation time, the number of closed-ring isomers increased, and the emission intensity also increased, reaching its maximum absorption value after 10 minutes.

[0105] (II) Characterization of diarylethylene nanofluorescent dyes

[0106] (1) Morphological characteristics

[0107] The morphological characteristics of the diarylethylene nanofluorescent dye prepared in Example 6 were observed. The distribution changes of the nanoparticles after standing for 12h, 24h, 48h, one week and longer were observed.

[0108] Transmission electron microscopy (TEM) images of nanoparticles after 12 hours and longer periods of inactivity, and scanning electron microscopy (SEM) images after 24 hours, 48 ​​hours, one week, and longer periods of inactivity. Figure 9 As shown, the average particle size of the nanoparticles is around 200 nm. After standing for a week, the ethanol evaporates, and the particle size of the nanoparticles increases significantly to around 300 nm. Furthermore, the aggregation of the particles intensifies. As time increases, the aggregation of the nanoparticles intensifies, resulting in a dendritic structure.

[0109] (2) Ultraviolet-absorption spectroscopy characterization

[0110] The UV-Vis absorption spectrum of the diarylethylene nanofluorescent dye is as follows: Figure 10 As shown. From Figure 10 It can be seen that the open-ring fluorescent nanodye exhibits an absorption band centered at 300 nm. After irradiation with a 365 nm ultraviolet light source, the fluorescent nanodye shows a new broad absorption band in the visible light region between 370 and 490 nm, revealing the formation of the closed-ring fluorescent nanodye.

[0111] like Figure 11 The image shows the color and fluorescence changes of closed-ring / open-ring fluorescent nanofibers under 365nm ultraviolet light irradiation. Figure 11 It can be seen that the open-ring fluorescent nano-dye compound BTF6O4Si appears green when irradiated by ultraviolet light, while the closed-ring fluorescent nano-dye compound BTF6O4Si appears orange-red after being irradiated by ultraviolet light for a period of time.

[0112] The visible light absorption range in the UV-Vis absorption spectrum of the open / closed ring fluorescent nanodye is consistent with the visible light absorption range in the UV-Vis absorption spectrum of BTF6O4Si molecules, but the color changes are different. This is due to the aggregation-induced emission (AIE) effect. Some specific molecules may not emit light in solution or in the solid state, but once the molecules aggregate, they self-regulate to achieve fluorescence enhancement. Therefore, when the molecules in the fluorescent nanodye aggregate, the color of the fluorescent nanodye is inconsistent with the color of the molecules.

[0113] (3) Fluorescence spectroscopy characterization

[0114] The fluorescence spectrum of open-ring nanofluorescent dyes is as follows: Figure 12 As shown, Figure 12 This indicates that the open-ring nanofluorescent dye exhibits a broad emission spectrum at room temperature, with the emission peak located at 500 nm.

[0115] The fluorescence spectrum of closed-ring nanofluorescent dyes is as follows: Figure 13 As shown in the figure, two peaks appear, located at 500nm and 593nm respectively.

[0116] Figure 14 The images show the color and fluorescence of the ring-opening fluorescent nanoparticles in their aggregated state under ultraviolet and visible light, respectively. Figure 15 The figures show the color and fluorescence changes of the closed-loop fluorescent nanodye in its aggregated state under ultraviolet light and visible light. As can be seen from the figures, the color and fluorescence changes of the fluorescent nanodye are different due to the AIE effect.

[0117] In summary, the diarylethylene nanofluorescent dye prepared by this invention can achieve dynamic fluorescence changes under ultraviolet and visible light irradiation, and has excellent fatigue resistance and thermal stability, and can be applied to fluorescent anti-counterfeiting materials.

[0118] Example 7: Anti-counterfeiting application of photochromic fluorescent dyes

[0119] The diarylethylene nanofluorescent dye prepared in Example 6 was used to prepare anti-counterfeiting patterns and anti-counterfeiting QR codes. The preparation method was as follows: the diarylethylene nanofluorescent dye was dissolved in dichloromethane to prepare a solution with a concentration of 3×10⁻⁶. -5 M. Using a capillary tube, the solution is drawn onto filter paper to create anti-counterfeiting patterns and QR codes. After the dichloromethane evaporates, the nanoparticles adhere to the filter paper.

[0120] (I) Application of anti-counterfeiting patterns and anti-counterfeiting QR codes

[0121] The anti-counterfeiting pattern and QR code were alternately exposed to ultraviolet light and visible light. The color comparison of the anti-counterfeiting pattern and QR code before and after ultraviolet light and visible light exposure is as follows: Figure 16 and Figure 17 As shown, before being irradiated with ultraviolet light, the pattern and QR code are colorless. After being irradiated with a 365nm ultraviolet light, the anti-counterfeiting pattern and QR code appear, emitting green fluorescence and showing a yellow pattern under sunlight, demonstrating superior photochromic performance. At this point, the QR code can be recognized, and the information can be easily read by scanning the QR code with a mobile phone. Subsequently, when irradiated with visible light, the pattern and QR code can reversibly return to their initial state, exhibiting excellent photostability and reversibility.

[0122] In summary, this invention utilizes diarylene photochromic nanofluorescent dyes to prepare light-driven dynamic fluorescent anti-counterfeiting patterns and QR codes, successfully achieving photochromic and reversible switching behavior. The prepared patterns and QR codes exhibit excellent thermal stability and photochromic properties, demonstrating the promising application prospects of diarylene photochromic nanofluorescent dyes in the field of anti-counterfeiting.

[0123] The above embodiments are intended to illustrate the essential content of the present invention, but are not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of protection of the present invention.

Claims

1. A diarylethylene compound, characterized in that, The structural formula of the diarylethylene compounds is shown in Formula 1: R1 and R2 are both selected from hydrogen atoms or trimethylsilyl ethynyl groups.

2. The diarylethylene compound according to claim 1, characterized in that, R1 is trimethylsilylethynyl, and R2 is selected from hydrogen atom or trimethylsilylethynyl.

3. The method for preparing the diarylethylene compound according to any one of claims 1 to 2, characterized in that, Includes the following steps: Under ice-water bath conditions, m-chloroperoxybenzoic acid was added to a solution of compound E, and the reaction was allowed to proceed overnight. The reaction was quenched, and the reaction solution was extracted with an organic solvent. The organic phase was collected, and the organic solvent in the organic phase was removed to obtain a crude product. After separation and purification, the crude product yielded a diarylethylene compound with the structural formula shown in Formula 1. The structural formula of compound E is shown in formula e: R1 and R2 are both selected from hydrogen atoms or trimethylsilyl ethynyl groups.

4. The method for preparing diarylethylene compounds according to claim 3, characterized in that, The molar ratio of compound E to m-chloroperoxybenzoic acid is 1:5 to 10.

5. The method for preparing diarylethylene compounds according to claim 3, characterized in that, The preparation of compound E includes: adding bis(triphenylphosphine)palladium dichloride, cuprous iodide, and trimethylsilylacetylene to a solution of compound D under an inert gas atmosphere, and heating at 60–80 °C for 10–20 h; after the reaction is complete, water is added to the reaction solution, followed by extraction with an organic solvent, collecting the organic phase, and removing the organic solvent from the organic phase to obtain a crude product; the crude product is then separated and purified to obtain compound E; the structural formula of compound D is shown in formula d: R1 and R2 are both selected from hydrogen atoms or iodine atoms.

6. The method for preparing diarylethylene compounds according to claim 5, characterized in that, The molar ratio of compound D to trimethylsilylacetylene is 1:1.4 to 1.

6.

7. A nano-fluorescent dye, characterized in that, The nanofluorescent dye comprises any one of the diarylethylene compounds according to claims 1 to 2.

8. The nanofluorescent dye according to claim 8, characterized in that, The nanofluorescent dye is prepared from the diarylethylene compounds described in any one of claims 1 to 2.

9. The nanofluorescent dye according to any one of claims 8 to 9, characterized in that, The structural formulas of the diarylethylene compounds are shown in Formula 1-1 or Formula 1-2:

10. The application of the nano-fluorescent dye as shown in any one of claims 7-9 in the field of anti-counterfeiting.

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