An imidazoene-bridged dithienylethylene photochromic compound and its preparation method and application

Abstract

The present invention belongs to the technical field of photochromic compounds, and specifically relates to an imidazole-bridged dithienylethylene photochromic compound and its preparation method and application. The preparation method is to synthesize the imidazole-bridged dithienylethylene photochromic compound in a container by heating reaction in one pot using 1,2-bis(2-methyl-5-phenylthiophene-3-yl)ethane-1,2-dione and R-CHO as raw materials, n-butanol as solvent, benzotriazole and ammonium acetate as catalysts. The method of the present invention is simple to operate, green and environmentally friendly, mild in conditions, and relatively easy to post-process. The method of the present invention successfully synthesizes the imidazole-bridged dithienylethylene photochromic compound that can achieve different color changes by fine-tuning the connecting group on the imidazole-bridge, providing a new approach for the development of full-color photochromic materials.

Description

Technical Field

[0001] The present invention belongs to the technical field of photochromic compounds, and in particular relates to an imidazole-bridged dithienylethylene photochromic compound and a preparation method and application thereof. Background Art

[0002] Dithienylethylene (DTE) is a photochromic compound composed of a pair of thiophene rings and a cyclic 1,2-vinyl bridge, including cyclopentene, thiazole, hexafluorocyclopentane, maleic anhydride, and maleimide. It is a type of diaryl compound. Its two thiophene rings provide it with strong electron donor ability, making dithienylethylene a suitable donor for constructing DA systems. In addition, dithienylethylene (DTE) compounds have unique bistability, high thermal stability, fast response, and excellent fatigue resistance. Therefore, they have been widely used in photoelectric switches, fluorescent switches, optical storage, and anti-counterfeiting.

[0003] Despite the promising applications of dithienylethylene compounds, traditional synthesis methods suffer from low efficiency and complex procedures. Typical synthesis processes involve lengthy organic solvent reflux cycles and tedious post-processing. Furthermore, the glacial acetic acid solvent used in traditional methods readily reacts with heteroatoms to form byproducts, affecting yield, purity, and the ultimate photochromic effect. Therefore, there is an urgent need to develop dithienylethylene compounds that are simple to operate, highly efficient, and minimize side effects. Summary of the Invention

[0004] The present invention aims to provide an imidazoene-bridged dithienylethylene photochromic compound, its preparation method, and its application. The method is carried out in air, under relatively mild reaction conditions, and provides a valuable reference for the synthesis of imidazoene-bridged dithienylethylene photochromic compounds, with broad research and development prospects.

[0005] The implementation process of the present invention is as follows:

[0006] An imidazole-bridged dithienylethylene photochromic compound, the general chemical formula of which is as follows:

[0007]

[0008] Wherein, R is selected from any one of thiazolyl, thienyl, phenyl, halogenphenyl, triphenylamine, tetraphenylethylene, and alkyl-substituted phenylboryl.

[0009] The preparation method of the above-mentioned imidazolyl-bridged dithienylethylene photochromic compound specifically comprises the following steps: in a container, using 1,2-bis(2-methyl-5-phenylthiophen-3-yl)ethane-1,2-dione and R-CHO as raw materials, n-butanol as solvent, benzotriazole and ammonium acetate as catalysts, and synthesizing the imidazolyl-bridged dithienylethylene photochromic compound in a one-pot process by heating reaction; R is selected from any one of thiazolyl, thienyl, phenyl, halophenyl, triphenylamine, tetraphenylethylene, and alkyl-substituted phenylborane;

[0010]

[0011] Furthermore, the molar ratio of 1,2-bis(2-methyl-5-phenylthiophene-3-yl)ethane-1,2-dione, R-CHO, benzotriazole, and ammonium acetate is 1:(1-1.5):(0.1-0.3):(5-10).

[0012] Furthermore, the temperature of the heating reaction is 70-90°C.

[0013] Furthermore, after the heating reaction is completed, the reactant is purified to obtain an imidazole-bridged dithienylethylene photochromic compound.

[0014] Furthermore, purification is performed by column separation.

[0015] Furthermore, the reaction of the raw materials was monitored using a TLC spot plate during the heating reaction process.

[0016] The above-mentioned imidazoene-bridged dithienylethylene photochromic compounds are used in optoelectronic devices, smart materials, display technology, fluorescent switches, optical storage, and anti-counterfeiting fields.

[0017] Furthermore, the imidazoene-bridged dithienylethylene photochromic compound can be used to store information reversibly and repeatedly.

[0018] Positive effects of the present invention:

[0019] (1) The present invention uses 1,2-bis(2-methyl-5-phenylthiophene-3-yl)ethane-1,2-dione as raw material and synthesizes imidazole-bridged dithiopheneethylene photochromic compounds in a one-pot process under the action of benzotriazole and ammonium acetate. The preparation method is simple to operate, green and environmentally friendly, with mild conditions and relatively easy post-processing.

[0020] (2) This invention explores the role of benzotriazole as a catalyst in the synthesis of imidazole-bridged dithienylethylene photochromic compounds. This method significantly improves the synthesis efficiency and application potential of imidazole-bridged dithienylethylene photochromic compounds, providing a solid foundation for their wide application in various fields.

[0021] (3) The group connected to the aldehyde in the present invention is any one of a thiazolyl group, a thienyl group, a phenyl group, a halogenphenyl group, a triphenylamine group, a tetraphenylethylene group, and an alkyl-substituted phenylborane group. By fine-tuning the connecting group on the imidazole ene bridge, a color-changing imidazole ene bridge-type dithienylethylene photochromic compound capable of achieving different color changes is successfully synthesized, providing a new approach for the development of full-color photochromic materials.

[0022] (4) The imidazoene-bridged dithienylethylene photochromic compound obtained by the method of the present invention is reversible and can be used repeatedly. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The target product A1 obtained in Example 1 1 H NMR spectrum;

[0024] Figure 2 The target product A2 obtained in Example 2 1 H NMR spectrum;

[0025] Figure 3 The target product A3 obtained in Example 3 1 H NMR spectrum;

[0026] Figure 4 The target product A4 obtained in Example 4 1 H NMR spectrum;

[0027] Figure 5 The target product A5 obtained in Example 5 1 H NMR spectrum;

[0028] Figure 6 This is the mass spectrum of the target product A5 obtained in Example 5;

[0029] Figure 7 The target product A6 obtained in Example 6 1 H NMR spectrum;

[0030] Figure 8 This is the mass spectrum of the target product A6 obtained in Example 6;

[0031] Figure 9 The target product A7 obtained in Example 7 1 H NMR spectrum;

[0032] Figure 10 This is the mass spectrum of the target product A7 obtained in Example 7;

[0033] Figure 11 The fluorescence color changes of products A1-A7 of Examples 1-7 under ultraviolet light and visible light irradiation;

[0034] Figure 12 This is the information recording performance test of the product A5 of Example 5. DETAILED DESCRIPTION

[0035] The present invention will be further described below with reference to the embodiments.

[0036] It should be noted that in the method of the present invention, the amount of n-butanol solvent used is not particularly limited, and those skilled in the art can add an appropriate amount of solvent based on experimental conditions and experience. The amount of solvent used in the method of the present invention is preferably 80 to 100 times the mass of 1,2-bis(2-methyl-5-phenylthiophen-3-yl)ethane-1,2-dione.

[0037] In the method of the present invention, the reaction time of the raw materials is monitored using a TLX spot plate during the heating reaction. If no raw materials are detected, it indicates that the raw materials have completely reacted, and the reaction can be stopped. Therefore, the method of the present invention does not impose any particular restrictions on the reaction time. The reaction times given in the examples are the times required for the raw materials to completely react.

[0038] In the method of the present invention, there is no particular limitation on the purification method. Those skilled in the art can select a purification method based on experimental conditions and experience. In the method of the present invention, dichloromethane / methanol with a volume ratio of 50 / 1 is preferably used as the eluent for column separation and purification.

[0039] Example 1

[0040]

[0041] 1,2-Bis(2-methyl-5-phenylthiophen-3-yl)ethane-1,2-dione (85 mg, 0.21 mmol), thiazole-5-carboxaldehyde (30 μL, 0.35 mmol), benzotriazole (5 mg, 0.042 mmol), and ammonium acetate (142.4 mg, 1.85 mmol) were added sequentially to a 50 mL reaction flask. 5 mL of n-butanol was added and stirred thoroughly. The reaction was allowed to proceed at 80°C for 12 h, monitored by TLC. After completion of the reaction, the mother liquor was evaporated to dryness. The crude product was separated by column chromatography using a 50 / 1 dichloromethane / methanol (volume ratio) as the eluent to obtain the desired product A1 as a yellow solid (54 mg, yield: 51.6%). The structure is shown below:

[0042]

[0043] That 1 H NMR spectrum is shown in Figure 1 , 1H NMR (400MHz, DMSO-d6) δ13.47(s,1H),7.97(d,J=3.2Hz,1H),7.81(d,J=3.2Hz,1H),7.61(dd,J=7.6,1. 7Hz,2H),7.54–7.49(m,3H),7.39(dt,J=19.8,7.6Hz,5H),7.33–7.25(m,3H),2.24(s,3H),2.11(s,3H). 13 C NMR(100MHz,DMSO-d6)δ143.9,141.3,139.7,139.2,137.0,135.8,135.2,133.9,1 33.4,129.7,129.6,128.0,127.8,126.1,125.6,125.4,125.3,125.2,14.5,14.3.

[0044] Example 2

[0045]

[0046] 1,2-Bis(2-methyl-5-phenylthiophen-3-yl)ethane-1,2-dione (85 mg, 0.21 mmol), thiophene-5-carboxaldehyde (30 μL, 0.32 mmol), benzotriazole (5 mg, 0.042 mmol), and ammonium acetate (142.4 mg, 1.85 mmol) were added sequentially to a 50 mL reaction flask. 5 mL of n-butanol was added and stirred thoroughly. The reaction was allowed to proceed at 80°C for 12 h, monitored by TLC. After completion of the reaction, the mother liquor was evaporated to dryness. The crude product was separated by column chromatography using a 50 / 1 dichloromethane / methanol (volume ratio) eluent to afford 73 mg of the target product A2 as a white solid in a 73.4% yield.

[0047] The structure is as follows:

[0048]

[0049] That 1 H NMR spectrum is shown in Figure 2 , 1 H NMR (400MHz, DMSO-d6)) δ12.64(s,1H),8.00(s,1H),7.72–7.61(m,4H),7.55–7.47(m,3H), 7.42(t,J=7.6Hz,2H),7.36(t,J=7.6Hz,2H),7.33–7.22(m,3H),2.27(s,3H),2.10(s,3H). 13C NMR (101MHz, DMSO-d6)) δ143.0,139.9,138.9,134.7,134.5,134.2,134.0,133.8,129. 6,129.6,128.0,127.7,127.5,126.3,125.8,125.4,125.2,123.2,122.0,14.64,14.27.

[0050] Example 3

[0051]

[0052] 1,2-Bis(2-methyl-5-phenylthiophen-3-yl)ethane-1,2-dione (85 mg, 0.21 mmol), benzaldehyde (25 μL, 0.25 mmol), benzotriazole (5 mg, 0.042 mmol), and ammonium acetate (142.4 mg, 1.85 mmol) were added sequentially to a 50 mL reaction flask. 5 mL of n-butanol was added and stirred thoroughly. The reaction was allowed to proceed at 80°C for 12 h, monitored by TLC. After completion of the reaction, the mother liquor was evaporated to dryness. The crude product was separated by column chromatography using a 50 / 1 dichloromethane / methanol (volume ratio) eluent to obtain the desired product A3 as a white solid (35 mg, yield 69.3%).

[0053] The structure is as follows:

[0054]

[0055] That 1 H NMR spectrum is shown in Figure 3 , 1 H NMR (400MHz, DMSO-d6) δ12.75(s,1H),8.08(d,J=7.3Hz,2H),7.65(d,J=7.7Hz,2H),7.59–7.4 5(m,5H),7.39(dq,J=16.5,8.5,7.9Hz,5H),7.27(d,J=17.5Hz,3H),2.32(s,3H),2.12(s,3H).

[0056] Example 4

[0057]

[0058] 1,2-Bis(2-methyl-5-phenylthiophen-3-yl)ethane-1,2-dione (85 mg, 0.21 mmol), p-fluorobenzaldehyde (30 μL, 0.28 mmol), benzotriazole (5 mg, 0.042 mmol), and ammonium acetate (142.4 mg, 1.85 mmol) were added sequentially to a 50 mL reaction flask. 5 mL of n-butanol was added and stirred thoroughly. The reaction was allowed to proceed at 80°C for 12 h, monitored by TLC. After completion of the reaction, the mother liquor was evaporated to dryness. The crude product was separated by column chromatography using a 50 / 1 dichloromethane / methanol (volume ratio) eluent to obtain the desired product A4 as a white solid (30 mg, yield 54.3%).

[0059] The structure is as follows:

[0060]

[0061] That 1 H NMR spectrum is shown in Figure 4 ,1H NMR (400MHz, DMSO-d6) δ12.76(s,1H),8.16–8.00(m,2H),7.64(d,J=7.6Hz,2H),7.63–7.49(m,3H),7.46–7.09(m,9H),2.31(s,3H),2.11(s,3H).

[0062] Example 5

[0063]

[0064] 1,2-Bis(2-methyl-5-phenylthiophen-3-yl)ethane-1,2-dione (85 mg 0.21 mmol), triphenylamine formaldehyde (68.8 mg 0.25 mmol), benzotriazole (5 mg 0.042 mmol), and ammonium acetate (142.4 mg 1.85 mmol) were added sequentially to a 50 mL reaction flask. 5 mL of n-butanol was added and stirred thoroughly. The reaction was allowed to proceed at 80°C for 12 h, monitored by TLC. After completion of the reaction, the mother liquor was evaporated to dryness. The crude product was separated by column chromatography using a 50 / 1 dichloromethane / methanol (volume ratio) as the eluent to obtain the desired product A5 as a white solid (44.2 mg, yield 52.6%).

[0065] The structure is as follows:

[0066]

[0067] That 1 H NMR spectrum is shown in Figure 5 , 1H NMR(400MHz, CDCl3)δ9.34(s,1H),7.78(d,J=8.4Hz,2H),7.58–7.45(m,4H),7.41–7.27(m,9H),7.21(d, J=10.2Hz,2H),7.13(d,J=8.1Hz,6H),7.06(t,J=7.4Hz,2H),2.26(s,3H),2.14(s,3H).HRMS(m / z):[M+H] + calcd for C 43 H 34 N3S2:656.2194,found:656.2200.

[0068] Its mass spectrum is shown in Figure 6 .

[0069] Example 6

[0070]

[0071] 1,2-Bis(2-methyl-5-phenylthiophen-3-yl)ethane-1,2-dione (85 mg 0.21 mmol), tetraphenylethylene formaldehyde (98.3 mg 0.27 mmol), benzotriazole (5 mg 0.042 mmol), and ammonium acetate (142.4 mg 1.85 mmol) were added sequentially to a 50 mL reaction flask. 5 mL of n-butanol was added and stirred thoroughly. The reaction was allowed to proceed at 80°C for 12 h, monitored by TLC. After completion of the reaction, the mother liquor was evaporated to dryness. The crude product was separated by column chromatography using a 50 / 1 dichloromethane / methanol (volume ratio) as the eluent to obtain the desired product A6 as a white solid (52.1 mg, yield 70.1%).

[0072] The structure is as follows:

[0073]

[0074] That 1 H NMR spectrum is shown in Figure 7 , 1 H NMR (400MHz, CDCl3) δ9.29 (s, 1H), 7.67 (d, J = 8.0Hz, 2H), 7.51 (d, J = 6.5Hz, 4H) ,7.41–7.28(m,6H),7.18(s,2H),7.16–7.00(m,17H),2.25(s,3H),2.13(s,3H). 13C NMR (101MHz, CDCl3) δ143.5,143.3,141.8,140.0,132.0,131.4,131.3,128.8,127.9,127.8,127.7,126.7,125.4,124.6,14.2.HRMS(m / z):[M+H] + calcd for C 51 H 39 N2S2:743.2555,found:743.2562.

[0075] Its mass spectrum is shown in Figure 8 .

[0076] Example 7

[0077]

[0078] 1,2-Bis(2-methyl-5-phenylthiophen-3-yl)ethane-1,2-dione (85 mg 0.21 mmol), 4-(dimethylboryl)benzaldehyde (96.7 mg 0.35 mmol), benzotriazole (5 mg 0.042 mmol), and ammonium acetate (142.4 mg 1.85 mmol) were added sequentially to a 50 mL reaction flask. 5 mL of n-butanol was added and stirred thoroughly. The reaction was allowed to proceed at 80°C for 12 h, monitored by TLC. After completion of the reaction, the mother liquor was evaporated to dryness. The crude product was separated by column chromatography using a 50 / 1 dichloromethane / methanol (volume ratio) as the eluent to obtain 111.8 mg of the target product A7 as a pale yellow solid in a 40.7% yield.

[0079] The structure is as follows:

[0080]

[0081] That 1 H NMR spectrum is shown in Figure 9 , 1 H NMR (400MHz, CDCl3) δ9.38(s,1H),7.91(d,J=7.9Hz,2H),7.62(d,J=8.1Hz,2H),7.58–7.48(m,4H),7.35(m,6H ),7.22(d,J=8.3Hz,2H),6.84(s,4H),2.32(s,6H),2.29(s,3H),2.16(s,3H),2.02(s,12H).HRMS(m / z):[M+H] + calcd for C 49 H 46 N2S2:737.3195,found:737.3203.

[0082] Its mass spectrum is shown in Figure 10 .

[0083] Example 8

[0084] 1,2-Bis(2-methyl-5-phenylthiophen-3-yl)ethane-1,2-dione (85 mg, 0.21 mmol), thiazole-5-carboxaldehyde (18 μL, 0.21 mmol), benzotriazole (2.5 mg, 0.021 mmol), and ammonium acetate (80.8 mg, 1.05 mmol) were added sequentially to a 50 mL reaction flask. 5 mL of n-butanol was added and stirred. The mixture was allowed to react at 70°C for 14 h, monitored by TLC. After the reaction, the mother liquor was evaporated to dryness. The crude product was separated by column chromatography using a 50 / 1 dichloromethane / methanol volume ratio as the eluent to obtain the desired product A8 as a yellow solid. The structure is shown below:

[0085]

[0086] Example 9

[0087] 1,2-Bis(2-methyl-5-phenylthiophen-3-yl)ethane-1,2-dione (85 mg, 0.21 mmol), thiophene-5-carboxaldehyde (30 μL, 0.32 mmol), benzotriazole (7.5 mg, 0.063 mmol), and ammonium acetate (161.6 mg, 2.1 mmol) were added sequentially to a 50 mL reaction flask. 5 mL of n-butanol was added and stirred thoroughly. The reaction was allowed to proceed at 90°C for 11 hours, monitored by TLC. After completion of the reaction, the mother liquor was evaporated to dryness. The crude product was separated by column chromatography using a 50 / 1 dichloromethane / methanol (volume ratio) as the eluent to obtain the desired product A9 as a white solid.

[0088] The structure is as follows:

[0089]

[0090] Fluorescence performance test:

[0091] The target products A1-A7 obtained in Examples 1-7 were prepared into solutions with the same concentration, and irradiated with a 365nm ultraviolet lamp to observe the color change of the solution. Figure 11 shown.

[0092] Information recording application performance test:

[0093] The imidazolyl-bridged dithienylethylene photochromic compound obtained by the method of the present invention has good reversibility on PMMA (polymethyl methacrylate) film, and is therefore used in optical information storage testing. Figure 12As shown, a PMMA film covered with a mask engraved with a rabbit pattern was coated with A5 powder, the product of Example 5. When exposed to 365nm UV light for 2 minutes, a green rabbit pattern was observed. This is because the A5 molecules exposed to UV light isomerize from an open ring state to a closed ring state, changing their color from colorless to green. The film remained colorless in the masked areas, creating a sharp contrast with the uncovered areas. Therefore, the rabbit pattern can be clearly observed under visible light.

[0094] Then turn off the UV lamp and use visible light to irradiate the PMMA film. The color of the film gradually fades and returns to colorless, and the rabbit pattern disappears. Figure 12 The recovered film can be used for the next information recording.

[0095] The above is a further detailed description of the present invention in conjunction with specific preferred embodiments, and the specific implementation of the present invention should not be considered to be limited to these descriptions. For those skilled in the art to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, and all of these should be considered to fall within the scope of protection of the present invention.

Claims

1. An imidazole-bridged dithienylethylene photochromic compound, characterized in that: The general chemical formula is as follows: Wherein, R is selected from thiazolyl, thienyl, phenyl, halogenphenyl, triphenylamine, tetraphenylethylene, Any one of them.

2. The method for preparing the imidazolyl-bridged dithienylethylene photochromic compound according to claim 1, characterized in that: In a container, 1,2-bis(2-methyl-5-phenylthiophen-3-yl)ethane-1,2-dione and R-CHO were used as raw materials, n-butanol was used as solvent, benzotriazole and ammonium acetate were used as catalysts, and imidazole-bridged dithienylethylene photochromic compounds were synthesized by a one-pot method through heating reaction; R was selected from thiazolyl, thienyl, phenyl, halophenyl, triphenylamine, tetraphenylethylene, Any one of 3. The preparation method according to claim 2, characterized in that: The molar ratio of 1,2-bis(2-methyl-5-phenylthiophene-3-yl)ethane-1,2-dione, R-CHO, benzotriazole and ammonium acetate is 1:(1-1.5):(0.1-0.3):(5-10).

4. The preparation method according to claim 2, characterized in that: The temperature of the heating reaction is 70-90°C.

5. The preparation method according to claim 2, characterized in that: After the heating reaction is completed, the reactant is purified to obtain an imidazole-bridged dithienylethylene photochromic compound.

6. The preparation method according to claim 5, characterized in that: Purification is performed by column separation.

7. The preparation method according to claim 2, characterized in that: The reaction of the raw materials was monitored using a TLC spot plate during the heating reaction process.

8. Use of the imidazoene-bridged dithienylethylene photochromic compound according to claim 1 in the fields of optoelectronic devices, smart materials, display technology, fluorescent switches, optical storage, and anti-counterfeiting.

9. The application according to claim 8, characterized in that: The imidazoene-bridged dithienylethylene photochromic compound can be used to store information reversibly and repeatedly.

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