Fluorine atom modified 2, 4, 6-triphenyl pyran salt derivative, preparation method thereof and application of fluorine atom modified 2, 4, 6-triphenyl pyran salt derivative in mechanochromic material

Abstract

The invention discloses fluorine atom modified 2, 4, 6-triphenyl pyran salt derivatives, a preparation method thereof and application in mechanochromic materials, small organic molecules of the fluorine atom modified 2, 4, 6-triphenyl pyran salt derivatives have good responsiveness to mechanical force stimulation, a compound I can achieve red shift of emission wavelength through grinding, and the compound II can achieve red shift of emission wavelength through grinding. The compound II can realize blue shift of emission wavelength through grinding, can meet the requirements of high-sensitivity response and multi-type signal output, and has a wide application prospect as a mechanochromic material.

Description

Technical Field

[0001] The present invention relates to the technical field of mechanochromic materials, and more specifically, to a class of fluorine atom-modified 2,4,6-triphenylpyrylium salt derivatives, a preparation method thereof, and an application thereof in mechanochromic materials. Background Art

[0002] Mechanical color-changing materials can undergo significant changes in their photophysical properties (such as emission wavelength, luminescence quantum yield, luminescence lifetime, etc.) under the stimulation of external mechanical forces (including static pressure, shear force, etc.). This unique stimulus response mode makes it a smart material with broad application prospects in stress sensing, memory chips, data storage, information security and other fields.

[0003] At present, organic small molecules have been widely used in the construction of mechanochromic materials. For example, by structurally modifying luminescent groups such as carbazole, triphenylamine, and pyrene, the molecules can be given better mechanochromic properties. Usually, the stacking pattern or change in molecular conformation of compounds under external mechanical force stimulation is the main reason why the material exhibits mechanochromic properties. However, most of the organic mechanochromic molecules reported so far have neutral molecular structures, and pure organic ionic mechanochromic molecules are still very rare. Compared with neutral molecules, ionic compounds have more flexible stacking methods and stronger electrostatic forces between molecules, so they may show more unique stimulus response signal changes.

[0004] As an ionic compound, pyrylium salt can show excellent luminescence properties through structural modification, but this type of structure still needs to be explored in the construction of mechanochromic materials. In particular, the construction of materials that can achieve high sensitivity response under mechanical force stimulation and multi-type signal output through structural modification still faces challenges. Summary of the invention

[0005] In view of this, the present invention provides a class of fluorine atom-modified 2,4,6-triphenylpyrylium salt derivatives, which are used to meet the performance requirements of high-sensitivity response and multi-type signal output under mechanical force stimulation.

[0006] The technical solution of the present invention is as follows: The first aspect of the present invention is to provide a fluorine atom-modified 2,4,6-triphenylpyrylium salt derivative having a structural formula shown in Formula I or Formula II: , .

[0007] The second aspect of the present invention is to provide a method for preparing the fluorine atom-modified 2,4,6-triphenylpyrylium salt derivative described in the first aspect, the steps comprising: S1. Condense fluorine atom-modified acetophenone with benzaldehyde under alkaline conditions to form a chalcone derivative intermediate; S2. React the obtained chalcone derivative intermediate with fluorine atom-modified acetophenone, and add a p-toluenesulfonate anion donor to obtain the fluorine atom-modified 2,4,6-triphenylpyrilium salt derivative; The fluorine atom-modified acetophenone has the structural formula shown in Formula III: ; In Formula III, R1 and R2 are each independently selected from F or H.

[0008] Further, in step S1, the molar ratio of the fluorine atom-modified acetophenone, benzaldehyde to the base is 1: (1~1.1): (1.2~1.3).

[0009] Further, in step S1, the reaction temperature is room temperature and the reaction time is 18~24 h.

[0010] Further, step S1 further includes a post-treatment step: extracting the reaction product, washing the organic phase, drying, removing the solvent and performing column chromatography separation to obtain the chalcone derivative intermediate.

[0011] Further, in step S2, the reaction process is carried out under an inert atmosphere. First, the temperature is raised to 40~50 °C, and after adding the p-toluenesulfonate anion donor in batches, the temperature is then raised to reflux for 36~48 hours.

[0012] Preferably, the inert atmosphere is nitrogen, the solvent used in the reaction is dichloromethane, and the reflux reaction temperature is 70~90 °C.

[0013] Further, in step S2, the p-toluenesulfonate anion donor is selected from p-toluenesulfonic acid, p-toluenesulfonate or p-toluenesulfonic acid hydrate.

[0014] Further, in step S2, the molar ratio of the chalcone intermediate, fluorine atom-modified acetophenone to the p-toluenesulfonate anion donor is (2~2.2): (1~1.1): 1.

[0015] Further, step S2 also includes a post-treatment step for the reaction product: concentrating the solvent by vacuum distillation, precipitating and pickling to obtain a solid, and performing recrystallization to obtain the fluorine atom-modified 2,4,6-triphenylpyrilium salt derivative.

[0016] In the third aspect of the present invention, it is proposed that the fluorine atom-modified 2,4,6-triphenylpyrilium salt derivative described in the first aspect or the fluorine atom-modified 2,4,6-triphenylpyrilium salt derivative obtained by the preparation method described in the second aspect is used in the preparation of a mechanochromic material.

[0017] Furthermore, the fields where the mechanochromic material can be used include, but are not limited to, writing records, mechanical sensing, anti-counterfeiting, information storage and other fields.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: The organic small molecule of the 2, 4, 6-triphenylpyranylium salt derivative modified with fluorine atoms of the present invention has good responsiveness to mechanical force stimulation. Compound I can achieve a red shift of the emission wavelength through grinding, and Compound II can achieve a blue shift of the emission wavelength through grinding, which can meet the requirements of high-sensitivity response and multi-type signal output, and has broad application prospects as a mechanochromic material; The synthesis process of the 2, 4, 6-triphenylpyranylium salt derivative modified with fluorine atoms of the present invention is simple and can be obtained only through simple aldol condensation reaction and addition reaction. Moreover, the raw materials are cheap and easy to obtain, the preparation cost is low, the overall molar yield of the synthesis route is greater than 40%, and the product purity is greater than 97%, which can be used for industrial production. Description of the Drawings

[0019] Figure 1 1H NMR spectrum of Compound I with mechanochromic properties; Figure 2 Fluorescence emission spectra of solid Compound I before and after grinding; where the excitation wavelength is λ ex = 400 nm; Figure 3 Time-resolved decay curves of solid Compound I before and after grinding; Figure 4 Photographs of the luminescence of solid Compound I before and after grinding under 365 nm ultraviolet light irradiation; Figure 5 1H NMR spectrum of Compound II with mechanochromic properties; Figure 6 Fluorescence emission spectra of solid Compound II before and after grinding; where the excitation wavelength is λ ex = 400 nm; Figure 7 Time-resolved decay curves of solid Compound II before and after grinding; Figure 8 Photographs of the luminescence of solid Compound II before and after grinding under 365 nm ultraviolet light irradiation. Detailed Description of the Invention

[0020] The following are specific implementation examples of the present invention, which are the preferred and detailed descriptions of the present invention. It should be understood that the specific implementation manners described in this specification are only for explaining the present invention and not for limiting the present invention.

[0021] In one embodiment, a preparation method of a 2,4,6-triphenylpyranylium salt derivative modified with fluorine atoms is proposed. The steps include: 1) Slowly add fluorinated acetophenone and benzaldehyde to a solvent, stir at room temperature for 5 min; add an aqueous solution of a base, and continue to stir at room temperature. After the reaction is completed, distill off the solvent under reduced pressure, wash with water, and purify by column chromatography to obtain a chalcone intermediate; 2) Add the chalcone intermediate and fluorinated acetophenone to a two-necked flask, dissolve with a solvent, stir and heat up under the protection of an inert gas, add a p-toluenesulfonate anion donor in batches, continue to heat up, and reflux the reaction. After the reaction is completed, concentrate the solvent by distillation under reduced pressure, precipitate, wash the solid with an acidic aqueous solution, and obtain the 2,4,6-triphenylpyranylium salt derivative modified with fluorine atoms by recrystallization.

[0022] In the above embodiment, the fluorinated acetophenone has the structural formula shown in Formula III: ; In Formula III, R1 and R2 are each independently selected from F or H; The entire process route of the preparation process is as follows: .

[0023] The prepared 2,4,6-triphenylpyranylium salt derivative modified with fluorine atoms has the structural formula shown in Formula I or Formula II: , .

[0024] In the above embodiment, the prepared 2,4,6-triphenylpyranylium salt derivative organic small molecule has good responsiveness to mechanical force stimulation. Compound I can achieve a red shift of the emission wavelength by grinding, and Compound II can achieve a blue shift of the emission wavelength by grinding.

[0025] In a preferred embodiment, step 1) is an aldol condensation reaction, and common basic catalysts are used, including potassium hydroxide and potassium carbonate: weak bases, suitable for substrates sensitive to strong bases, and need to react under heating in a polar solvent (such as DMF, DMSO); piperidine: an organic weak base, commonly used in reactions without solvent or in ethanol conditions, with mild reaction and good selectivity.

[0026] In a preferred embodiment, the solvent used in step 1) can be selected from ethanol, methanol, or an ethanol-aqueous solution, and ethanol is more preferred.

[0027] In a preferred embodiment, in step 1), taking sodium hydroxide as an example of the basic catalyst, the molar ratio of the fluorine atom-modified acetophenone, benzaldehyde to sodium hydroxide is 1:(1~1.1):(1.2~1.3).

[0028] In a preferred embodiment, in step 1), the room temperature is 25±5°C, and the reaction time is 18~24 hours.

[0029] In a preferred embodiment, in the process of column chromatography separation and purification in step 1), the eluent selected is petroleum ether:ethyl acetate = 10:1.

[0030] In a preferred embodiment, in step 2), in the reaction process, first heat up to 40~50°C, add the p-toluenesulfonate anion donor in batches, and then heat up to reflux for 36~48 hours; preferably, the reaction solvent is dichloromethane or toluene, and the reflux reaction temperature is 70~90°C.

[0031] In a preferred embodiment, in step 2), the p-toluenesulfonate anion donor is selected from p-toluenesulfonic acid or p-toluenesulfonic acid hydrate.

[0032] In a preferred embodiment, in step 2), the molar ratio of the chalcone intermediate, the fluorine atom-modified acetophenone and the p-toluenesulfonate anion donor is (2~2.2):(1~1.1):1.

[0033] In a preferred embodiment, in step 2), the acidic aqueous solution used for washing is a dilute hydrochloric acid solution with a pH of 1~2.5.

[0034] The following are preferred implementation examples. Unless otherwise specified, the reagents used are commercially available standard reagents in the art, and the experimental means used are means known in the art.

[0035] Example 1

[0036] Synthesize compound I:

[0037] The synthesis route is as follows:

[0038] In the reaction formula, NaOH is sodium hydroxide, EtOH is ethanol, TsOH·H2O is p-toluenesulfonic acid monohydrate, 1,4-dichloroethane is 1,2-dichloroethane, and N2 is nitrogen.

[0039] The specific synthesis steps are as follows: 1. Add 4-fluoroacetophenone (4.00 g, 28.96 mmol), benzaldehyde (3.07 g, 26.63 mmol) and ethanol (80 mL) into a round-bottom flask, and stir for 5 min at 25 °C. Slowly add an aqueous solution of sodium hydroxide (1.39 g, 34.75 mmol, 50 mL water), and continue to stir at room temperature for 24 h. After the reaction is completed, the reaction solution is extracted with dichloromethane three times, and the organic phases are combined, dried over anhydrous sodium sulfate, and the solvent is removed by distillation under reduced pressure to obtain a crude product. The crude product is separated and purified by column chromatography (petroleum ether:ethyl acetate = 20:1) to obtain a white solid ( E )-1-(4-fluorophenyl)-3-phenyl-2-propen-1-one, with a molar yield of 96.1% and a purity of 98.3%; 2. Add ( E )-1-(4-fluorophenyl)-3-phenyl-2-propen-1-one (1.50 g, 6.63 mmol) and 4-fluoroacetophenone (0.46 g, 3.31 mmol) into a two-necked flask, dissolve them in 5 mL of 1,2-dichloroethane, evacuate, fill with nitrogen, heat up to 50 °C, stir for a period of time, and add p-toluenesulfonic acid monohydrate (0.63 g, 3.15 mmol) in batches. Continue to heat up to 85 °C and reflux for 48 h. After the reaction is completed, the solvent is removed by distillation under reduced pressure. The remaining crude product is dissolved in a small amount of dichloromethane, and the solution is slowly added to a beaker containing ether, and the solid-liquid mixture is centrifuged. The solid sample is washed several times with an aqueous solution adjusted to pH = 2.00 with hydrochloric acid, and then dissolved in a small amount of dichloromethane. It is slowly added to a beaker containing ether, and the solid-liquid mixture is centrifuged and dried to obtain a yellow solid powder compound I, with a molar yield of 45.2% and a purity of 99.3%. The nuclear magnetic resonance hydrogen spectrum is as Figure 1 shown, 1 H NMR (600 MHz, D2O) δ 8.68 (s, 2H), 8.37 (d, J = 6.8 Hz, 4H), 8.17 (d, J =8.0 Hz, 2H), 7.79 (d, J = 7.8 Hz, 1H), 7.71 (t, J = 7.8 Hz, 2H), 7.64 (d, J = 8.0Hz, 2H), 7.45 (t, J = 8.6 Hz, 4H), 7.33 (d, J = 7.9 Hz, 2H), 2.36 (s, 3H).

[0040] Example 2

[0041] The synthesis steps of Compound I are as follows: 1. Add 4-fluoroacetophenone (4.00 g, 28.96 mmol), benzaldehyde (3.07 g, 26.63 mmol) and methanol (80 mL) into a round-bottom flask, and stir at 20 °C for 5 min. Then slowly add an aqueous solution of potassium hydroxide (1.95 g, 34.75 mmol, 50 mL water), and continue to stir at 20 °C for 24 h. After the reaction is completed, the reaction solution is extracted with dichloromethane three times, and the organic phases are combined, dried over anhydrous sodium sulfate, and the solvent is removed by distillation under reduced pressure to obtain a crude product. The crude product is separated and purified by column chromatography (petroleum ether: ethyl acetate = 20:1) to obtain a white solid ( E )-1-(4-fluorophenyl)-3-phenyl-2-propen-1-one, with a molar yield of 95.0% and a purity of 98.1%; 2. Add ( E )-1-(4-fluorophenyl)-3-phenyl-2-propen-1-one (1.50 g, 6.63 mmol) and 4-fluoroacetophenone (0.46 g, 3.31 mmol) into a two-necked flask, dissolve them in 5 mL of toluene, evacuate, fill with nitrogen, heat up to 45 °C, stir for a period of time, and then add p-toluenesulfonic acid (0.54 g, 3.15 mmol) in batches. Continue to heat up to 85 °C and reflux for 48 h. After the reaction is completed, the solvent is removed by distillation under reduced pressure. The remaining crude product is dissolved in a small amount of dichloromethane, and the solution is slowly added to a beaker containing ether, and the solid-liquid mixture is centrifuged. The solid sample is washed repeatedly with an aqueous solution with pH = 2.00 adjusted with hydrochloric acid, and then dissolved in a small amount of dichloromethane, and slowly added to a beaker containing ether, and the solid-liquid mixture is centrifuged and dried to obtain a yellow solid powder compound, with a molar yield of 44.1% and a purity of 99.1%. The compound is identified as Compound I by 1H NMR.

[0042] Example 3

[0043] The synthesis steps of Compound I are as follows: 1. Add 4-fluoroacetophenone (4.00 g, 28.96 mmol), benzaldehyde (3.07 g, 26.63 mmol) and ethanol (80 mL) into a round-bottom flask, and stir at 27 °C for 5 min. Then slowly add piperidine (2.95 g, 34.75 mmol), and continue to stir at 27 °C for 24 h. After the reaction is completed, the reaction solution is extracted with dichloromethane three times, and the organic phases are combined, dried over anhydrous sodium sulfate, and the solvent is removed by distillation under reduced pressure to obtain a crude product. The crude product is separated and purified by column chromatography (petroleum ether: ethyl acetate = 20:1) to obtain a white solid ( E )-1-(4-fluorophenyl)-3-phenyl-2-propen-1-one, with a molar yield of 93.2% and a purity of 98.4%; 2. Add ([ E E )-1-(4-fluorophenyl)-3-phenyl-2-propen-1-one (1.50 g, 6.63 mmol) and 4-fluoroacetophenone (0.46 g, 3.31 mmol) into a two-necked flask. Dissolve them in 5 mL of 1,2-dichloroethane, evacuate the air, fill with nitrogen gas, heat up to 50 °C, stir for a period of time, and then add p-toluenesulfonic acid monohydrate (0.63 g, 3.15 mmol) in batches. Continue to heat up to 90 °C and reflux for 40 h. After the reaction is completed, remove the solvent by distillation under reduced pressure. Dissolve the remaining crude product in a small amount of dichloromethane, slowly add the solution into a beaker containing ether, and centrifuge to separate the solid-liquid mixture. Wash the solid sample with an aqueous solution of hydrochloric acid adjusted to pH = 2.00 multiple times, then dissolve it in a small amount of dichloromethane again, slowly add it into a beaker containing ether, centrifuge to separate the solid-liquid mixture, and dry to obtain a yellow solid powder compound with a molar yield of 45.4% and a purity of 99.4%. It is identified as compound I by 1H NMR.

[0044] Example 4

[0045] Synthesize compound II:

[0046] The synthetic route is as follows:

[0047] In the reaction formula, NaOH is sodium hydroxide, EtOH is ethanol, TsOH·H2O is p-toluenesulfonic acid monohydrate, 1,4-dichloroethane is 1,2-dichloroethane, and N2 is nitrogen gas.

[0048] The specific synthesis steps are as follows: 1. Add 2-fluoroacetophenone (4.00 g, 28.96 mmol), benzaldehyde (3.07 g, 26.63 mmol) and ethanol (80 mL) into a round-bottom flask, and stir at 25 °C for 5 min. Then slowly add an aqueous solution of sodium hydroxide (1.39 g, 34.75 mmol, 50 mL of water), and continue to stir at 25 °C for 24 h. After the reaction is completed, extract the reaction solution with dichloromethane 3 times, combine the organic phases, dry over anhydrous sodium sulfate, and remove the solvent by distillation under reduced pressure to obtain a crude product. The crude product is separated and purified by column chromatography (petroleum ether:ethyl acetate = 20:1) to obtain a yellow oily liquid ([ E E )-1-(2-fluorophenyl)-3-phenyl-2-propen-1-one with a molar yield of 78.5% and a purity of 97.3%; 2. Add ([ E E)-1-(2-Fluorophenyl)-3-phenyl-2-propen-1-one (1.50 g, 6.63 mmol) and 2-fluoroacetophenone (0.46 g, 3.31 mmol) were dissolved in 5 mL of 1,2-dichloroethane. The mixture was evacuated and filled with nitrogen, then heated to 50 °C. After stirring for a period of time, p-toluenesulfonic acid monohydrate (0.63 g, 3.15 mmol) was added in batches. The temperature was further raised to 85 °C and the mixture was refluxed for 48 h. After the reaction was completed, the solvent was removed by distillation under reduced pressure. The remaining crude product was dissolved in a small amount of dichloromethane, and the solution was slowly added to a beaker containing ether. The solid-liquid mixture was centrifuged. The solid sample was washed several times with an aqueous solution adjusted to pH = 2.00 with hydrochloric acid, then dissolved in a small amount of dichloromethane again, slowly added to a beaker containing ether, and the solid-liquid mixture was centrifuged and dried to obtain a yellow solid powder compound II with a molar yield of 51.3% and a purity of 98.2%. The 1H NMR spectrum is as follows Figure 5 shown as 1 1H NMR (600 MHz, D2O) δ 8.78 (s, 2H), 8.25 (t, J J = 7.7 Hz, 2H), 8.20 (d, J J = 7.8 Hz, 2H), 7.85 (q, J J = 8.1 Hz, 3H), 7.73 (t, J J = 7.7 Hz, 2H), 7.68 (d, J J = 7.9 Hz, 2H), 7.55 (t, J J = 7.7 Hz, 2H), 7.50 (dd, J J = 12.0, 8.4 Hz, 2H), 7.36 (d, J J = 8.0 Hz, 2H), 2.39 (s, 3H).

[0049] Example 5

[0050] The specific synthesis steps of compound II are as follows: 1. Add 2-fluoroacetophenone (4.00 g, 28.96 mmol), benzaldehyde (3.07 g, 26.63 mmol) and methanol (80 mL) to a round-bottom flask and stir at 20 °C for 5 min. Then, an aqueous solution of potassium hydroxide (1.95 g, 34.75 mmol, 50 mL of water) was slowly added, and the mixture was continuously stirred at 20 °C for 24 h. After the reaction was completed, the reaction solution was extracted 3 times with dichloromethane, and the organic phases were combined and dried over anhydrous sodium sulfate. The solvent was removed by distillation under reduced pressure to obtain a crude product. The crude product was separated and purified by column chromatography (petroleum ether:ethyl acetate = 20:1) to obtain a yellow oily liquid (E )-1-(2-Fluorophenyl)-3-phenyl-2-propen-1-one, with a molar yield of 78.7% and a purity of 97.5%; 2. Add to the two-necked flask ([[]] E )-1-(2-Fluorophenyl)-3-phenyl-2-propen-1-one (1.50 g, 6.63 mmol) and 2-fluoroacetophenone (0.46 g, 3.31 mmol), dissolve in 5 mL of toluene, evacuate, fill with nitrogen, heat to 50 °C, stir for a period of time, add p-toluenesulfonic acid (0.54 g, 3.15 mmol) in batches, continue to heat to 90 °C, and reflux for 40 h. After the reaction is completed, distill off the solvent under reduced pressure. The remaining crude product is dissolved in a small amount of dichloromethane, and the solution is slowly added to a beaker containing ether. The solid-liquid mixture is centrifuged. The solid sample is washed multiple times with an aqueous solution adjusted to pH = 2.00 with hydrochloric acid, and then dissolved in a small amount of dichloromethane. It is slowly added to a beaker containing ether, and the solid-liquid mixture is centrifuged and dried to obtain a yellow solid powder compound, with a molar yield of 51.4% and a purity of 98.4%. It is identified as Compound II by 1H NMR spectroscopy.

[0051] Example 6

[0052] The specific synthesis steps for synthesizing Compound II are as follows: 1. Add 2-fluoroacetophenone (4.00 g, 28.96 mmol), benzaldehyde (3.07 g, 26.63 mmol) and ether (80 mL) to a round-bottom flask, and stir at 27 °C for 5 min. Slowly add piperidine (2.95 g, 34.75 mmol), and continue to stir at 27 °C for 24 h. After the reaction is completed, the reaction solution is extracted 3 times with dichloromethane, and the organic phases are combined and dried over anhydrous sodium sulfate. The solvent is removed by distillation under reduced pressure to obtain a crude product. The crude product is separated and purified by column chromatography (petroleum ether:ethyl acetate = 20:1) to obtain a yellow oily liquid E )-1-(2-Fluorophenyl)-3-phenyl-2-propen-1-one, with a molar yield of 76.1% and a purity of 97.0%; 2. Add to the two-necked flask ([[]] E)-1-(2-Fluorophenyl)-3-phenyl-2-propen-1-one (1.50 g, 6.63 mmol) and 2-fluoroacetophenone (0.46 g, 3.31 mmol) were dissolved in 5 mL of toluene. The mixture was evacuated and filled with nitrogen, then heated to 45 °C. After stirring for a period of time, p-toluenesulfonic acid (0.54 g, 3.15 mmol) was added in batches, and the temperature was further raised to 85 °C. The mixture was refluxed for 48 h. After the reaction was completed, the solvent was removed by distillation under reduced pressure. The remaining crude product was dissolved in a small amount of dichloromethane, and the solution was slowly added to a beaker containing ether. The solid-liquid mixture was centrifuged. The solid sample was washed repeatedly with an aqueous solution of hydrochloric acid adjusted to pH = 2.00, then dissolved in a small amount of dichloromethane again, slowly added to a beaker containing ether, and the solid-liquid mixture was centrifuged and dried to obtain a yellow solid powder compound with a molar yield of 51.2% and a purity of 98.0%. It was identified as compound II by 1H NMR spectrum.

[0053] Experimental Example 1 Detection of the Fluorescent Mechanochromic Properties of Compound I

[0054] Compound I in Example 1 was treated and tested in the following different ways.

[0055] 1) Take the solid of Compound I, use 400 nm as the excitation light, and test its fluorescence emission spectrum. The maximum fluorescence emission peak of Compound I is 518 nm, and the solid-state fluorescence quantum yield is 4.45%.

[0056] 2) Take the solid of Compound I and grind it thoroughly in a mortar. Use 400 nm as the excitation light and test its fluorescence emission spectrum. The maximum fluorescence emission peak of the ground Compound I is 592 nm, and the solid-state fluorescence quantum yield is 2.16%.

[0057] 3) Take the solid sample of Compound I and test the luminescence lifetime at its maximum emission wavelength with a transient fluorescence spectrometer.

[0058] 4) Take the solid of Compound I and grind it thoroughly in a mortar. Test the luminescence lifetime at its maximum emission wavelength with a transient fluorescence spectrometer.

[0059] 5) Take the solid sample of Compound I and irradiate it with 365 nm ultraviolet light, then take its fluorescence photograph.

[0060] 6) Place the solid of Compound I in a mortar and grind it thoroughly, irradiate it with 365 nm ultraviolet light, and take its fluorescence photograph.

[0061] As Figure 2As shown, Compound I has fluorescence mechanical stimulus responsiveness. When we thoroughly ground Compound I with a pestle, the maximum fluorescence emission wavelength red-shifted from 518 nm to 592 nm. The fluorescence quantum yield decreased from 4.45% to 2.16%. Before and after grinding, the lifetimes of the emission wavelengths of the compound at 518 nm and 592 nm were 1.97 ns and 18.11 ns respectively ( Figure 3 ). Under the irradiation of a 365 nm ultraviolet lamp, it can be clearly seen that mechanical grinding caused the fluorescence color of the compound to change from green to yellow ( Figure 4 ). The above results indicate that the photophysical properties of Compound I change significantly after being stimulated by mechanical force, suggesting its mechanochromic property.

[0062] Experimental Example 2 Detection of the mechanochromic fluorescence property of Compound II

[0063] Compound II was processed and tested in the following different ways.

[0064] 1) Take the prepared solid of Compound II and use 400 nm as the excitation light to test its fluorescence emission spectrum. Compound II has two emission peaks, located at 487 nm and 546 nm respectively, and the solid-state fluorescence quantum yield is 7.35%.

[0065] 2) Place the prepared solid of Compound II in a mortar and thoroughly grind it. Use 400 nm as the excitation light to test its fluorescence emission spectrum. The ground Compound II has two emission peaks, located at 487 nm and 530 nm respectively, and the solid-state fluorescence quantum yield is 2.74%.

[0066] 3) Take the prepared solid sample of Compound II and use a transient fluorescence spectrometer to test the luminescence lifetimes of its two emission peaks.

[0067] 4) Place the prepared solid of Compound II in a mortar and thoroughly grind it. Use a transient fluorescence spectrometer to test the luminescence lifetimes of its two emission peaks.

[0068] 5) Take the prepared solid sample of Compound II and irradiate it with 365 nm ultraviolet light to take its fluorescence photo.

[0069] 6) Place the prepared solid of Compound II in a mortar and thoroughly grind it. Irradiate it with 365 nm ultraviolet light to take its fluorescence photo.

[0070] As Figure 6As shown, Compound II has fluorescence mechanical stimulation responsiveness. When we thoroughly grind Compound II with a pestle, its emission peak at 546 nm blue-shifts to 530 nm, while the emission peak at 487 nm does not change significantly. The fluorescence quantum yield decreases from 7.35% to 2.74%. Before grinding, the emission peak lifetimes of the compound at 546 nm and 487 nm are 4.07 ns and 0.98 ns respectively; after grinding, the emission peak lifetimes of the compound at 530 nm and 487 nm are 3.72 ns and 1.37 ns respectively; ( Figure 7 ). Under the irradiation of a 365 nm ultraviolet lamp, it can be clearly seen that mechanical grinding causes the fluorescence color of the compound to change from yellow-green to green ( Figure 8 ). The above results show that the photophysical properties of Compound II change significantly after being stimulated by mechanical force, indicating its mechanochromic properties.

[0071] Finally, it should be noted that although the present invention has been described in detail with general descriptions and specific embodiments above, on the basis of the present invention, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. 2,4,6-Triphenylpyranylium salt derivatives modified with fluorine atoms, characterized in that, The fluorine atom-modified 2,4,6-triphenylpyranylium salt derivative has the structural formula shown in Formula II: 。 2. The preparation method of the fluorine atom-modified 2,4,6-triphenylpyranylium salt derivative according to claim 1, characterized in that the step Including: S1. Condensation reaction of fluorine atom-modified acetophenone with benzaldehyde under alkaline conditions to generate a chalcone derivative intermediate; S2. React the obtained chalcone derivative intermediate with fluorine atom-modified acetophenone, and add a p-toluenesulfonate anion donor to obtain the fluorine atom-modified 2,4,6-triphenylpyranylium salt derivative; The fluorine atom-modified acetophenone has the structural formula shown in Formula III: ； In Formula III, R1 is H and R2 is F.

3. The preparation method according to claim 2, wherein In step S1: The molar ratio of the fluorine atom-modified acetophenone, benzaldehyde to the base is 1:(1~1.1):(1.2~1.3); and / or, the reaction temperature is room temperature and the reaction time is 18~24 h.

4. The preparation method according to claim 2, wherein, Step S1 also includes a post-treatment step: extracting the reaction product, washing the organic phase, drying, removing the solvent and subjecting to column chromatography separation to obtain the chalcone derivative intermediate.

5. The preparation method according to claim 2, characterized in that, In step S2, the reaction process is carried out under an inert atmosphere. First, the temperature is raised to 40~50 °C, and after adding the p-toluenesulfonate anion donor in batches, the temperature is then raised to reflux for 36~48 hours.

6. The preparation method according to claim 2, characterized in that, In step S2, the p-toluenesulfonate anion donor is selected from p-toluenesulfonic acid or p-toluenesulfonic acid hydrate.

7. The preparation method according to claim 2, characterized in that, In step S2, the molar ratio of the chalcone intermediate, fluorine atom-modified acetophenone to the p-toluenesulfonate anion donor is (2~2.2):(1~1.1):

1.

8. The preparation method according to claim 2, characterized in that, Step S2 also includes a post-treatment step for the reaction product: concentrating the solvent by vacuum distillation, precipitating and pickling to obtain a solid, and recrystallizing to obtain the fluorine atom-modified 2,4,6-triphenylpyranylium salt derivative.

9. Use of a fluorine atom-modified 2,4,6-triphenylpyrilium salt derivative in the preparation of a mechanochromic fluorescent material, characterized in that, The fluorine atom-modified 2,4,6-triphenylpyranylium salt derivative has the structural formula shown in Formula I or Formula II: 、 。 10. The application according to claim 9, characterized in that The fluorine atom-modified 2,4,6-triphenylpyranylium salt derivative with the structure of Formula I changes from fluorescent green to yellow after being stimulated by mechanical force; and / or, the fluorine atom-modified 2,4,6-triphenylpyranylium salt derivative with the structure of Formula II changes from fluorescent yellow to green after being stimulated by mechanical force.

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