DASAs molecular optical switch capable of realizing solid film isomerization and synthesis method and application thereof

Abstract

The invention discloses a DASAs molecular optical switch capable of realizing solid film isomerization and a synthesis method and application thereof. The DASAs molecular optical switch is 5-((2Z, 4E)-5-(benzyl ((4-methylpyridine-2-yl) methyl) amino)-2-hydroxypent-2, 4-diene-1-subunit)-2, 2-dimethyl-1, 3-dioxane-4, 6-diketone, 4-methylpyridine-2-formaldehyde reacts with benzylamine, then N-benzyl-1-(4-methylpyridine-2-yl) methylamine is synthesized through reduction of sodium borohydride, and then the DASAs molecular optical switch is obtained. The preparation method comprises the following steps: reacting 2, 3-dimethoxy-1, 3-dioxane-4, 6-diketone in methanol, and reacting with 5-(furan-2-yl methylene)-2, 2-dimethyl-1, 3-dioxane-4, 6-diketone in methanol to synthesize the compound. The DASAs molecular photoswitch disclosed by the invention has rapid and reversible isomerization response to visible light and shows remarkable selective color response to metal ions, and in addition, the molecular photoswitch can realize reversible photochromism in a solid state in a polymer substrate. More importantly, the pure-phase solid film prepared by the molecular optical switch can realize photoisomerization, and has huge application potential in the fields of optical information storage and information permanent encryption, metal ion detectors and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of organic synthesis, and relates to a DASAs molecular optical switch capable of realizing solid film isomerization, and a synthesis method and application thereof. Background Art

[0002] Donor-acceptor Stenhouse adducts (DASAs) are a class of photochromic molecules that can respond rapidly to visible light. They can quickly convert from a colored chain structure to a colorless ring structure, and this process can be reversibly restored by heat under light-proof conditions. Compared with traditional color-changing materials that require high-energy ultraviolet light response, they show significant advantages. The photoresponsive properties of DASAs include negative photochromism, visible light absorption, synthetic tunability, and significant property changes between photoisomers, which make DASAs ideal candidates for photochromic materials. Another significant advantage of DASAs is their excellent synthetic tunability. By changing the molecular structure, their photoresponsive properties can be adjusted to achieve optimal performance within a specific wavelength range. This tunability provides a broad space for designing photochromic materials with specific application requirements.

[0003] However, existing research focuses on the photochromic properties of DASAs molecules. In addition, like traditional photoresponsive compounds, DASAs exhibit rapid, reversible and efficient isomerization in solution, but in the solid state, this isomerization is often hindered due to factors such as the π-π stacking of chromophores or inherent mobility limitations, which undoubtedly limits the development and application of solid-state DASAs photoresponsive materials. ([1]Photoswitching using visible light:A new class oforganic photochromic molecules.Helmy, Sameh,et al.Journal of the AmericanChemical Society,2014,136(23):8169-72.[2]Design and Synthesis of Donor-Acceptor Stenhouse Adducts:A Visible Light Photoswitch Derived fromFurfural.Sameh Helmy,et al.Journal of the Organic Chemistry, 2014, 79, 11316-11329. [3] Structure-function relationships of donor-acceptor Stenhouse adductphotochromic switches. Mallo, Neil, et al. Chemical Science, 2018, 43, 8242-8252.). Therefore, it is necessary to further explore new molecular design strategies and material synthesis methods in order to break through existing limitations and improve the multiple stimulus response behavior and solid-state isomerization performance of DASAs photochromic materials, so as to develop new photochromic molecules with more diverse responses and adaptable to multiple states, and achieve in-depth expansion of the DASAs molecular switch function. Summary of the invention

[0004] The purpose of the present invention is to provide a DASAs molecular optical switch capable of realizing solid film isomerization, and a synthesis method and application thereof.

[0005] The technical solution for achieving the purpose of the present invention is as follows:

[0006] The DASAs molecular light switch that can realize solid thin film isomerization is 5-((2Z,4E)-5-(benzyl((4-methylpyridin-2-yl)methyl)amino)-2-hydroxypenta-2,4-diene-1-ylidene)-2,2-dimethyl-1,3-dioxane-4,6-dione, and its structural formula is shown in Formula III:

[0007]

[0008] The synthesis method of the DASAs molecular light switch capable of realizing solid thin film isomerization comprises the following steps:

[0009] (1) Using methanol as solvent, 4-methylpyridine-2-carboxaldehyde and benzylamine are reacted at 78±5°C. After the reaction is complete, sodium borohydride is added under ice-water bath for reduction, and then heated to reflux. After the reaction is complete, the mixture is cooled, and the methanol is removed by rotary evaporation. Extraction and rotary evaporation are performed to obtain N-benzyl-1-(4-methylpyridin-2-yl)methylamine. The synthetic route is as follows:

[0010]

[0011] (2) At room temperature, with methanol as solvent, 5-(furan-2-ylmethylene)-2,2-dimethyl-1,3-dioxane-4,6-dione and N-benzyl-1-(4-methylpyridin-2-yl)methylamine undergo electrophilic addition reaction to prepare 5-((2Z,4E)-5-(benzyl((4-methylpyridin-2-yl)methyl)amino)-2-hydroxypenta-2,4-diene-1-ylidene)-2,2-dimethyl-1,3-dioxane-4,6-dione. The synthetic route is as follows:

[0012]

[0013] Furthermore, in step (1), the molar ratio of 4-methylpyridine-2-carboxaldehyde to benzylamine is 1:1.05-1.1.

[0014] Furthermore, in step (1), the reduction reaction time is more than 1 h, and the reflux reaction time is more than 20 h.

[0015] Furthermore, in step (1), the extraction solvent is CH2Cl2.

[0016] Furthermore, in step (2), the molar ratio of 5-(furan-2-ylmethylene)-2,2-dimethyl-1,3-dioxane-4,6-dione to N-benzyl-1-(4-methylpyridin-2-yl)methanamine is 1:1.05 to 1.1.

[0017] Furthermore, in step (2), the reaction temperature is 23±3°C and the reaction time is 25 to 30 min.

[0018] Furthermore, the present invention provides the above-mentioned DASAs molecular light switch in Fe 3+ 、Al 3+ Cu 2+ Application in detection.

[0019] Furthermore, the present invention provides the use of the above-mentioned DASAs molecular optical switch in the preparation of rewritable materials or information encryption materials.

[0020] Furthermore, the specific method of the above application is: dissolving the DASAs molecular light switch in an organic solvent, and then recording information during the process of the organic solvent volatilizing to form a solid film, forming a solid film after the organic solvent evaporates completely, erasing the recorded information through visible light stimulation, and obtaining an information permanent encryption material composed of the DASAs molecular light switch solid film; or mixing a polymer and a DASAs molecular light switch and dissolving them in an organic solvent, and then recording and erasing information through alternating stimulation of visible light and heat to obtain a rewritable material or information encryption material composed of the DASAs molecular light switch solid polymer film.

[0021] Furthermore, the organic solvent used to prepare the DASAs molecular photoswitch solid film is 1,1,1,3,3,3-hexafluoro-2-propanol; the organic solvent used to prepare the DASAs molecular photoswitch solid polymer film is chloroform, and the polymer used is polymethyl methacrylate (PMMA).

[0022] Compared with the prior art, the present invention has the following advantages:

[0023] (1) The synthesis method of the present invention is simple, the raw materials used are environmentally friendly and low in cost, the reaction conditions are mild, the reaction speed is fast, the yield of the target product is high, and the purification process is simple.

[0024] (2) The present invention selects methanol solvent when synthesizing the target molecular optical switch, rather than tetrahydrofuran solvent used in the existing synthesis technology route. By using methanol solvent, the present invention not only optimizes the synthesis conditions, but also has relatively low toxicity compared to tetrahydrofuran, which greatly avoids safety risks during use and is suitable for industrial production application scenarios.

[0025] (3) The molecular photoswitch of the present invention has multiple stimulus response behaviors in different environments, including light responsiveness, selective metal ion responsiveness (based on solution environment) and photoisomerization responsiveness in solid environment. It can realize photochromism in solid film state and has great application potential in the fields of metal ion detectors, information storage and encryption, and rewritable materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is the hydrogen nuclear magnetic resonance spectrum of compound I.

[0027] Figure 2 This is the H NMR spectrum of compound III.

[0028] Figure 3 This is the two-dimensional COSY spectrum of compound III.

[0029] Figure 4 This is the infrared spectrum of compound III.

[0030] Figure 5 The UV-vis absorption spectrum of compound III in dichloromethane shows that the absorbance varies with concentration, wherein a) is the full spectrum of absorbance varying with concentration, and b) is the linear relationship between absorbance and concentration.

[0031] Figure 6 The UV-vis absorption spectrum of compound III in acetonitrile solution shows that the absorbance varies with concentration, wherein a) is the full spectrum of absorbance varying with concentration, and b) is the linear relationship between absorbance and concentration.

[0032] Figure 7 This is the UV-vis absorption spectrum of compound III in dark equilibrium in dichloromethane solution.

[0033] Figure 8 This is the UV-vis cycle diagram of the reversible change of absorbance of compound III in dichloromethane solution with light response.

[0034] Fig. 9 This is the dark equilibrium UV-vis absorption spectrum of compound III in tetrahydrofuran solution.

[0035] Fig.10 This is the UV-vis cycle diagram of the reversible change of absorbance of compound III in tetrahydrofuran solution with light response.

[0036] Fig.11 This is a comparison chart of the color changes in response to metal ions of compound III.

[0037] Fig.12 To add different concentrations of Fe 3+ After responsive metal ions, the absorbance change of compound III is shown in UV-vis graph a) and the linear relationship between the absorbance of compound III at 531 nm and concentration is shown in graph b).

[0038] Fig.13 To add different concentrations of Al 3+ After responsive metal ions, the absorbance change of compound III is shown in UV-vis graph a) and the linear relationship between the absorbance of compound III at 531 nm and concentration is shown in graph b).

[0039] Fig.14 To add different concentrations of Cu 2+ After responsive metal ions, the absorbance change of compound III is shown in UV-vis graph a) and the linear relationship between the absorbance of compound III at 531 nm and concentration is shown in graph b).

[0040] Fig.15 Schematic diagram of the reversible isomerization of compound III using PMMA as a substrate under light stimulation and heating stimulation.

[0041] Fig.16 This is the UV-vis graph of the isomerization of compound III solid film under light stimulation and heating stimulation. DETAILED DESCRIPTION

[0042] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0043] The structural formula of 5-(furan-2-ylmethylene)-2,2-dimethyl-1,3-dioxane-4,6-dione (Compound I) of the present invention is: The method is prepared by the existing method, and can be prepared by the following steps:

[0044] In a double-necked flask, according to the molar ratio of 2-furaldehyde: cycloisopropyl malonate = 1.1:1, first add cycloisopropyl malonate into the flask, use deionized water as the solvent, slowly add 2-furaldehyde dropwise under stirring at room temperature, and react at 25°C for 2.5h. After the reaction is completed, CH2Cl2 is added to extract the crude product, CH2Cl2 is used to extract the aqueous phase (25ml*3), and then the organic phase is collected. Saturated NaHSO4 and saturated NaHCO3 solutions are added successively, and the CH2Cl2 phase is washed 3 times respectively, and then anhydrous sodium sulfate is added to dry a small amount of water in the organic phase, and the organic solvent is removed under reduced pressure. The oil pump is evacuated to obtain a yellow oily compound I. It was characterized by nuclear magnetic resonance, and the results are as follows Figure 1 shown.

[0045] Example 1

[0046] (1) Compound II is N-benzyl-1-(4-methylpyridin-2-yl)methylamine, and its molecular structure is shown below:

[0047]

[0048] Prepared by the following steps:

[0049] In a double-necked flask, 4-methylpyridine-2-carboxaldehyde was added according to the molar ratio Benzylamine First, add 4-methyl-2-pyridinecarboxaldehyde to a flask, use methanol as solvent, and slowly add benzylamine under stirring at 78±5℃. After the reaction is complete, add sodium borohydride for reduction in an ice-water bath for 1h, and then reheat the reaction flask for reflux reaction for 22h. After the reaction is completed, cool and remove the organic solvent by rotary evaporation. Add CH2Cl2 to dissolve the crude product, and add saturated NaCl solution and saturated NH4Cl solution at the same time. Wash the CH2Cl2 phase three times, collect the lower organic phase, and rotary evaporate to obtain N-benzyl-1-(4-methylpyridin-2-yl)methylamine.

[0050] (2) Target compound III is 5-((2Z,4E)-5-(benzyl((4-methylpyridin-2-yl)methyl)amino)-2-hydroxypenta-2,4-diene-1-ylidene)-2,2-dimethyl-1,3-dioxane-4,6-dione, and its molecular structure is shown below:

[0051]

[0052] Prepared by the following steps:

[0053] At room temperature, in a single-necked flask, compound II was added at a molar ratio of N-Benzyl-1-(4-methylpyridin-2-yl)methanamine Methanol was added, and after reacting at 25°C for 25 to 30 minutes, a purple-red solid was produced. The solid was precipitated and washed with anhydrous ether in an ice-water bath, filtered, and the precipitate was collected to obtain a high-purity target compound III with a yield of 93.5%. It was characterized by nuclear magnetic resonance and infrared. The infrared spectrum data of compound III was measured by potassium bromide tablet method, and the results were as follows: Figure 2-4 shown.

[0054] Example 2

[0055] Concentration-dependent effects of compound III:

[0056] In visible light max =550nm wavelength, compound III was added dropwise into the dichloromethane solution in the same concentration gradient, and the concentration-dependent performance characterization results were measured as follows: Figure 5 shown.

[0057] Figure 5 Figure a) shows the UV-vis absorption spectrum of compound III in dichloromethane as its concentration changes, with the maximum absorbance at 546 nm. Figure 5 Figure b) shows the linear relationship between the absorbance of compound III at 546 nm and its concentration. This shows that the dichloromethane solution of compound III has a good linear relationship (R 2 =0.99761), and the maximum absorption wavelength does not change with concentration.

[0058] Figure 6 is the UV-vis absorption spectrum of compound III in acetonitrile as its concentration changes, and the linear relationship between the absorbance of compound III at 546 nm and its concentration, R 2 =0.99995.

[0059] Example 3

[0060] Reversible photoresponse test of compound III:

[0061] Compound III was dissolved in dichloromethane (DCM) and tetrahydrofuran (THF) respectively to prepare c = 1.0 × 10 - 3 mol / L solution, and then the compound III solution in each solvent was placed in a 3 ml cuvette to prepare a concentration of c = 1.0 × 10 -5 mol / L solution (the solution is purple-red), and its dark equilibrium UV-vis absorption spectrum in DCM and THF solutions was obtained, such as Figure 7 and Fig. 9 shown.

[0062] Figure 8 The UV-vis graph of the reversible photoswitching performance of compound III in DCM. Figure 7 It can be seen that compound III has max = The absorbance at 546nm decreased from 0.9999 to 0.7397. The solution was irradiated with a visible xenon light source with a wavelength of 550nm, and it was found that the solution quickly faded from purple to colorless, and the absorbance was measured to be 0.0179. After being placed in the dark for 7.2h, the isomerization of compound III reached equilibrium, and the absorbance value was the maximum (the solution was purple at this time), such as Figure 8 Repeated testing revealed that after 7 to 8 cycles, the dark recovery of compound III in DCM solution would have a lower degree of attenuation, indicating that it has good cyclic anti-fatigue performance. The experimental results are shown in Figure 8 As shown in Figure c).

[0063] Fig.10 The UV-vis graph of the reversible photoswitching performance of compound III in THF. Fig. 9 It can be seen that compound III has max = The absorbance at 546nm decreased from 0.9746 to 0.7821. The solution was irradiated with a visible xenon light source with a wavelength of 550nm, and it was found that the solution quickly faded from purple to colorless, and the absorbance was measured to be 0.0196. It was placed in the dark for 9.8 hours until it returned to equilibrium, and the change of its maximum absorption peak in THF over time was measured as follows Fig.10As shown in Figure b), the cycle was repeated to test its anti-fatigue performance. It was found that after more than 4 cycles, the dark recovery degree of compound III in THF solution was almost not attenuated, and the cyclic anti-fatigue performance was good, which can be used as a good molecular light switch. The experimental results are shown in Fig.10 As shown in Figure c).

[0064] Example 4

[0065] Metal ion response of compound III:

[0066] Fig.11 The comparison chart of the color change of compound III in response to metal ions. Compound III was dissolved in methanol to a concentration of 1×10 -4 mol / L solution (the solution is purple-red), and then prepare a concentration of 10 -3 mol / L of metal ions (Na + ,Mg 2+ , Al 3+ , Mn 2+ , Fe 3+ , Fe 2+ ,Co 2+ , Ni 2+ , Cu 2+ , Zn 2+ ) solution, compound III and metal ions were mixed in a molar ratio of 1:4. The experimental results are as follows Fig.11 As shown, it was found that the addition of Fe 3+ The compound solution quickly faded from purple to colorless within 5 minutes; adding Al 3+ , Cu 2+ The solution gradually faded to colorless after 3.5 h.

[0067] In order to further confirm the relationship between compound III and Fe 3+ 、Al 3+ , Cu 2+ Is there a linear relationship between metal ions? Add Fe in proportion 3+ After metal ions, Fig.12 It can be seen that the absorbance of compound III decreases rapidly (the solution is eventually colorless), and the absorbance of compound III at 531 nm is linearly related to the concentration (y = -0.31582x + 1.00346, R 2 =0.91887); from Fig.13 and Fig.14 It can also be seen that compound III has 3+ , Cu 2+ After the metal ion is added, the absorbance decreases rapidly (the solution is finally colorless), and the absorbance of compound III at 531 nm is linearly related to the concentration (y = -0.0.08614x + 0.95861, R2 =0.95093; y=-0.10069x+0.98813, R 2 =0.98021). This indicates that compound III has a 3+ and Al 3 + , Cu 2+ It has a special isomerization response, and the response time is different and shows a good linear relationship. It can selectively detect the presence of these three types of ions in the solution according to the response time, and can be used to prepare highly selective and sensitive metal ion detection sensors.

[0068] Example 5

[0069] Solid-phase conversion performance of compound III molecular switch in polymer:

[0070] Fig.15 The figure is a schematic diagram of the reversible isomerization of compound III under light stimulation and heating stimulation using PMMA as a substrate. In order to further explore the isomerization response of compound III under different environments, it was found through research that the functional groups in the polymer closely affect the kinetics and equilibrium of DASAs isomerization, and a variety of ester-containing polymers may enhance the isomerization of DASAs in polymer films. Therefore, the present invention chooses PMMA as the polymer substrate to explore the isomerization performance of compound III in a solid phase environment. Take 0.5g PMMA in a beaker, add 5mg compound III, dissolve in chloroform, ultrasonically dissolve, place in a cube mold, dry naturally, wait for the solvent to evaporate to form a film, and obtain a polymer film of compound III. By Fig.15 It can be seen that compound III in a solid phase film based on PMMA, when irradiated with visible light (JB450 nm), the polymer film faded from purple-red to colorless, and then the film was placed in an oven for heating, and it was found that the film returned from colorless to purple-red. Experiments have shown that through alternating stimulation of visible light and heating, the polymer solid film exhibits a reversible color change response and good cycle performance. This discovery provides a new idea for solving the isomerization problem of DASAs in the solid state, indicating that compound III has broad application prospects in the fields of optical information storage and rewritable materials.

[0071] Example 6

[0072] Photochromic properties of molecular light switch solid film of compound III:

[0073] Fig.16 The UV-vis graph of the isomerization of the solid film of compound III under light stimulation and heating stimulation. The present invention selects 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) as a solvent, grinds the above-synthesized compound III molecular switch into powder, and r=434 g·mol -1 Quantitative calculation: 8.68 mg was dissolved in 10 ml of HFIP and the standard concentration was 2.0 × 10 -3 mol·L -1 The coating liquid of compound III was prepared, and a flat laboratory table was selected. The prepared compound III coating liquid was quantitatively suspended on the outside of a clean quartz cuvette to ensure that the surface of the cuvette was evenly coated. The solid film of compound III molecular optical switch was successfully prepared after the solvent evaporated and formed into a film. The solid film of compound III was placed under a xenon lamp (JB450 nm) for illumination. When the illumination time T = 5min, the maximum characteristic absorption peak (λ max =558nm) decreased significantly, and the solid film also gradually faded from purple to red. After 10 minutes of illumination, its absorbance reached a stable state and no longer decreased. This shows that the solid film of the colored compound III successfully underwent photofading after being exposed to visible light. The maximum absorption wavelength λ of the solid film under JB450 nm illumination is max =The absorbance at 558nm changes with illumination time as shown in Fig.16 As shown in Figure c).

[0074] The solid film obtained after light exposure was heated in an oven. It was found that as the temperature increased, the film did not return to purple-red from colorless. The change of its absorbance with temperature was monitored by UV-visible absorption spectroscopy. Fig.16 From the red line in the graph b), it can be observed that when the temperature rises to 95°C, the maximum absorption peak at 558nm does not increase. If the temperature is further increased, the absorbance will decrease. It is speculated that the photoisomerization of compound III is easier to form a stable double closed-loop structure, so it is difficult to achieve reversible thermal isomerization. The solid film of compound III of the present invention exhibits irreversible isomerization behavior under light and heat stimulation conditions, and this characteristic makes it show great application prospects in the field of permanent information encryption technology. Specifically, the film can make the area carrying colored secret information fade effectively after reading through a simple visible light irradiation process until it is completely transformed into a colorless state, thereby cleverly realizing the hiding and protection of information. It is particularly important that this fading process is irreversible, that is, once the information is hidden, even conventional means such as heating cannot make the secret information appear again, fundamentally eliminating the risk of information leakage, and ensuring the security and reliability of information in the permanent encryption process. Therefore, the present invention not only provides a new technical means for information encryption, but also takes an important step in ensuring information security and preventing information leakage.

Claims

1. A DASAs molecular light switch capable of realizing solid thin film isomerization, characterized in that: 5-((2 Z ,4 E )-5-(benzyl((4-methylpyridin-2-yl)methyl)amino)-2-hydroxypenta-2,4-diene-1-ylidene)-2,2-dimethyl-1,3-dioxane-4,6-dione, the structural formula is shown in Formula III: 。 2. The method for synthesizing the DASAs molecular photoswitch according to claim 1, characterized in that: The steps include: (1) Using methanol as solvent, 4-methylpyridine-2-carboxaldehyde and benzylamine are reacted at 78±5°C. After the reaction is complete, sodium borohydride is added under ice-water bath for reduction, and then heated to reflux. After the reaction is completed, the mixture is cooled, and the methanol is removed by rotary evaporation. Extraction and rotary evaporation are performed to obtain N -benzyl-1-(4-methylpyridin-2-yl)methanamine; (2) At room temperature, with methanol as solvent, 5-(furan-2-ylmethylene)-2,2-dimethyl-1,3-dioxane-4,6-dione and N -benzyl-1-(4-methylpyridin-2-yl)methanamine undergoes an electrophilic addition reaction to prepare 5-((2Z,4E)-5-(benzyl((4-methylpyridin-2-yl)methyl)amino)-2-hydroxypenta-2,4-diene-1-ylidene)-2,2-dimethyl-1,3-dioxane-4,6-dione.

3. The synthesis method according to claim 2, characterized in that In step (1), the molar ratio of 4-methylpyridine-2-carboxaldehyde to benzylamine is 1:1.05-1.1; the reduction reaction time is more than 1 h, and the reflux reaction time is more than 20 h.

4. The synthesis method according to claim 2, characterized in that In step (1), the extraction solvent is CH2Cl2.

5. The synthesis method according to claim 2, characterized in that In step (2), based on the molar ratio, 5-(furan-2-ylmethylene)-2,2-dimethyl-1,3-dioxane-4,6-dione: N -benzyl-1-(4-methylpyridin-2-yl)methylamine=1:1.05~1.

1.

6. The synthesis method according to claim 2, characterized in that In step (2), the reaction temperature is 23±3°C and the reaction time is 25~30 min.

7. The DASAs molecular light switch according to claim 1 is used in Fe 3+ 、Al 3+ Cu 2+ Application in detection.

8. Use of the DASAs molecular photoswitch according to claim 1 in preparing rewritable materials or information encryption materials.

9. The use according to claim 8, characterized in that: The specific method is as follows: dissolving the DASAs molecular light switch in an organic solvent, then recording information during the process of the organic solvent volatilizing to form a solid film, and after the organic solvent evaporates completely, obtaining a permanent information encryption material composed of the DASAs molecular light switch solid film; or mixing a polymer and a DASAs molecular light switch and dissolving them in an organic solvent, then recording information during the process of the organic solvent volatilizing to form a solid film, and after the organic solvent evaporates completely, obtaining a rewritable material or information encryption material composed of the DASAs molecular light switch solid polymer film.

10. The use according to claim 9, characterized in that: The organic solvent used to prepare the DASAs molecular light switch solid film is 1,1,1,3,3,3-hexafluoro-2-propanol; the organic solvent used to prepare the DASAs molecular light switch solid polymer film is chloroform, and the polymer used is PMMA.

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