Preparation of triarylethene solid photochromic dye and crystal of triarylethene solid photochromic dye

Abstract

The invention discloses a solid photochromic fluorescent compound containing a sulfoxide group and a synthesis method of the solid photochromic fluorescent compound. The preparation method comprises the following steps: reacting a brominated triaryl ethylene fluorescent compound easy to synthesize with diphenyl disulfide to obtain a thioether fluorescent compound, and oxidizing to obtain a sulfoxide fluorescent compound. Besides, through different crystallization methods, the triarylstyrene fluorescent compound containing the sulfoxide group can obtain crystals in two stacking modes, one of the crystals has photochromic performance, and research on the relation between the stacking mode and the photochromic performance is facilitated.

Description

Technical Field

[0001] The invention relates to the field of organic photochromic fluorescent materials, in particular to the application of triarylethene solid photochromic dye and a preparation method thereof. Background Art

[0002] When photochromic materials are exposed to light of a certain wavelength and intensity, specific chemical reactions can occur to cause changes in structure and color, and the original structure and color can be restored under the action of light of another wavelength, that is, the entire process is reversible. Combined with the characteristics of precision of light stimulation and remote controllability, photochromic compounds as a kind of smart material have attracted people's attention due to their wide applications in information storage, data encryption, trademark anti-counterfeiting and other fields. Therefore, the construction of new solid-state photochromic materials and the controllable regulation of their properties are of great significance for expanding the application of such compounds.

[0003] Researchers have found that the photochromic properties of solid compounds are closely related to the conformation and structure of the compounds (ACSApplied Materials Interfaces 2019, 11, 34526−34531). However, the current reports are mainly about changing the conformation of compounds through external stimuli such as heating, cooling, grinding, fumigation of solvents, etc., thereby changing the photochromic properties of compounds. However, it is impossible to obtain comparable crystal structure diagrams without changing the structure of the compounds, so it is difficult to distinguish the effects of molecular conformation or stacking mode on their performance. Homogeneous polymorphism provides an opportunity to adjust the molecular stacking mode and physicochemical properties, and achieve controllable regulation of compound performance (Current Organic Chemistry, 2017, 21, 236-248). At the same time, it provides comparable crystal structure diagrams, which can deeply explain the relationship between molecular conformation, stacking mode and light stimulus responsiveness, which will help to truly explain the structure-activity relationship at the molecular level.

[0004] At present, the main photochromic systems are spiropyrans, azo compounds, diarylethenes, spirooxazines and other compounds, which are mainly caused by changes in the conjugated system due to chemical reactions, such as proton transfer tautomerism, heterolysis and homolysis of chemical bonds, cis-trans isomerism, and pericyclic reactions. However, we know that the color of compounds will change due to changes in the stacking pattern. The stacking pattern of compounds can be changed by light stimulation, thereby causing color changes (Nature Communnication, 2018,9, 840). And conformational changes are not prone to other side reactions, which is beneficial to the stability of the compound. Therefore, the development of new photochromic compounds with conformational changes of light-stimulated compounds has potential development prospects. Summary of the invention

[0005] The object of the present invention is to provide a method for preparing a triarylethene compound containing a sulfoxide group with simple operation and high yield.

[0006] Another object of the present invention is to provide a new photochromic compound.

[0007] The third object of the present invention is to provide a photochromic compound with homogeneous polycrystals for studying the structure-activity relationship between conformation and photochromic properties.

[0008] The technical solution of the present invention is as follows: The molar ratio of substrate to oxidant is 1:0.5-1:1.2.

[0009] The reaction time of oxidation is 0.1-24h.

[0010] The oxidant is meta-chloroperbenzoic acid or hydrogen peroxide.

[0011] The purity of meta-chloroperbenzoic acid is 75% or 85%.

[0012] The concentration of hydrogen peroxide is 15% or 30%.

[0013] The structures of the compounds were confirmed by NMR and high-resolution mass spectrometry.

[0014] When preparing crystals by diffusion recrystallization, the good solvent selected is one of dichloromethane, ethyl acetate, acetonitrile, and tetrahydrofuran. When preparing single crystals, the poor solvent selected is one or more of n-hexane, methanol, and toluene. The recrystallization temperature is -20~30 ℃. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to further illustrate the features and technical contents of the present invention, the accompanying drawings are provided for reference and explanation.

[0016] Figure 1 It is the UV-visible spectrum before and after illumination. Figure 1 It shows that the organic fluorescent dye described in the embodiment of the present invention has photochromic characteristics.

[0017] Figure 2 is the fluorescence emission spectrum, Figure 2 Studies have shown that the two crystal structures of the organic fluorescent dye described in the embodiments of the present invention have different emission wavelengths. DETAILED DESCRIPTION

[0018] The following examples are helpful to further understand the present invention, but the contents of the present invention are not limited thereto. Example

[0019]

[0020] Under nitrogen, add the intermediate product triphenylethylene bromide (3.35 g, 10 mmol) and anhydrous THF (100 mL) to a 250 mL three-necked flask. When the temperature of the reaction system drops to -78°C, slowly add n-butyl lithium (8 mL, 2.5 mol / L, 20 mmol). After continuing to react at -78°C for 1 h, add diphenyl disulfide (2.62 g, 12 mmol). After one hour, the temperature of the reaction system was raised to room temperature and the stirring was continued for two hours. 50 mL of saturated NH4Cl solution was slowly added to the reaction bottle, and then the reaction solution was extracted with 150 mL of organic solvent DCM solution three times. The collected organic layer was washed again three times with 50 mL of saturated NaCl solution, and then an appropriate amount of anhydrous Na2SO4 was added for drying. Finally, the solvent was removed by rotary evaporation under negative pressure (-0.1 MPa) with a water pump. The crude product was purified by silica gel column chromatography (petroleum ether (60–90°C) as eluent) to obtain a thioether compound (1.9 g, yield 52%, white solid, melting point, 97°C). 1 H NMR (400 MHz, CDCl3) δ 7.31 – 7.18 (m, 11H, Ar-H), 7.18 – 7.08 (m, 4H, Ar-H), 7.00 (s, 1H), 6.98 (s, 1H), 6.89 –6.82 (m, 3H, Ar-H). 13 C NMR (100 MHz, CDCl3) δ 143.4, 143.1, 140.3, 136.3,135.5, 134.4, 131.4, 130.39, 130.35, 130.3, 129.3, 128.9, 128.4, 127.74,127.69, 127.4, 127.3. HR-MS (ESI + ) m / z Calcd for C 26 H 20 S [M+H] +365.1358; found365.1356. Add thioether compound (416 mg, 1.14 mmol) and DCM (50 mL) to a 100 mL round-bottom flask. When the system temperature drops to 0°C, add m-chloroperbenzoic acid (75%, 393.5 mg, 1.71 mmol) to the reaction system in several portions. Two hours later, add 50 mL of saturated sodium bicarbonate solution to the reaction system, and then extract the reaction solution with 150 mL of organic solvent DCM solution three times. Add an appropriate amount of anhydrous sodium sulfate to the collected organic layer for drying, and finally use a water pump to remove the solvent by rotary evaporation under negative pressure (-0.1 MPa). The crude product is separated and further purified by column chromatography (eluent: petroleum ether (60–90°C) / DCM = 3:1, v / v) to obtain the target product (434 mg, yield 85%, white solid, melting point, 116°C). 1 H NMR (400 MHz, CDCl3) δ 7.56 (d, J = 3.8 Hz, 2H, Ar-H), 7.45 – 7.18(m, 13H, Ar-H), 7.08 (dd, J = 26.0, 5.5 Hz, 4H, Ar-H), 6.88 (s, 1H). 13 C NMR (101MHz, CDCl3) δ 145.5, 145.0, 143.3, 142.9, 140.6, 139.8, 131.1, 130.4, 130.3,129.4, 128.9, 128.4, 128.1, 127.9, 127.8, 126.6, 124.84, 124.82. HR-MS (ESI + )m / z Calcd for C 26 H 20 SO [M+H] + 381.1308; found 381.1299.

Claims

1. A triarylethene solid photochromic fluorescent dye, characterized in that: The general structure is as follows: ， Where X = SO, SO2; R = methyl, methoxy, fluorine, chlorine.

2. The method for synthesizing the triarylethene solid photochromic fluorescent dye according to claim 1, wherein the preparation method comprises the following steps: ① Compound 1 reacts with diphenyl disulfide and post-processes to obtain an intermediate product (sulfide compound 2); ； ② The sulfide compound 2 is dissolved in a solvent, and 0.5 to 1.2 equivalents of an oxidant are used for post-treatment to obtain a sulfoxide compound; 。 3. The method for synthesizing the triarylethene photochromic fluorescent compound according to claim 2, characterized in that: The molar ratio of substrate to oxidant is 1:0.5-1:1.2; the oxidation reaction temperature is 0-30°C; the oxidation reaction time is 0.1-24 h; and the oxidant is m-chloroperbenzoic acid or hydrogen peroxide.

4. The method for synthesizing the triarylethene photochromic fluorescent compound according to claim 3, characterized in that: The purity of the selected meta-chloroperbenzoic acid is 75% or 85%, and the concentration of the hydrogen peroxide is 30% or 15%.

5. The method for preparing the crystal of triarylethene photochromic fluorescent compound according to claim 4, characterized in that: When recrystallizing by diffusion, the good solvent selected is one or more of dichloromethane, ethyl acetate, acetonitrile, and tetrahydrofuran; the poor solvent selected is one or more of n-hexane, methanol, and toluene; and the recrystallization temperature is -20~30°C.

6. The triarylethene solid photochromic fluorescent dye according to claim 1 is used in the preparation of trademark anti-counterfeiting products.

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