Preparation method and application of ultraviolet light response afterglow luminescent color-changing film
A simplified chemical synthesis method was used to prepare an ultraviolet light-responsive afterglow luminescent color-changing film, which solved the problem of complex preparation of pure organic room temperature phosphorescent materials and achieved a low-cost, high-efficiency long afterglow luminescence effect, suitable for anti-counterfeiting materials.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-24
- Publication Date
- 2026-03-20
AI Technical Summary
The preparation process of existing pure organic room temperature phosphorescent materials is cumbersome and complex, which severely limits their large-scale application in fields such as anti-counterfeiting materials. Furthermore, it is difficult to effectively control the spin-orbit coupling effect within/between molecules to achieve efficient phosphorescence emission.
Using D-tryptophan and para-formylbenzoic acid as raw materials, a specific phosphorescent molecule was synthesized through a series of chemical reactions and dispersed in PVA aqueous solution. The ultraviolet light-responsive afterglow luminescent color-changing film was prepared by drop coating method.
The preparation process is simple and low-cost, and the prepared color-changing film exhibits a long afterglow phenomenon under ultraviolet light excitation, with a phosphorescence lifetime of up to 3.19s, making it suitable for anti-counterfeiting applications.
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Figure CN121699321A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of luminescent materials technology, specifically to a method for preparing and applying an ultraviolet light-responsive afterglow luminescent color-changing film. Background Technology
[0002] Organic room-temperature phosphorescent materials, due to their large Stokes shift, long decay lifetime, and long afterglow, have significant application value in fields such as anti-counterfeiting materials, molecular switches, and bioimaging. Compared with traditional inorganic or organometallic phosphorescent systems, pure organic room-temperature phosphorescent materials have advantages such as safety, non-toxicity, low cost, and good processability, showing broad application prospects. However, pure organic room-temperature phosphorescent materials are very scarce, and existing preparation processes are cumbersome and complex, with harsh synthesis conditions, severely limiting the large-scale application of phosphorescent materials. Therefore, it is essential to develop efficient, long-lifetime phosphorescent materials and explore their application value in cutting-edge scientific and technological fields.
[0003] Achieving high-efficiency pure organic phosphorescence emission at room temperature primarily hinges on effectively controlling intramolecular / intermolecular spin-orbit coupling to promote singlet excitons to triplet excitons via intersystem crossing, thereby realizing high-efficiency phosphorescent pure organic RTP materials. However, most existing methods in the field of organic light-emitting materials require sophisticated molecular design and complex synthesis techniques. Summary of the Invention
[0004] The purpose of this invention is to address the aforementioned problems by providing a simple preparation method for a UV-responsive afterglow luminescent color-changing film and its application.
[0005] The technical solution of this invention is: In a first aspect, the present invention provides an ultraviolet light-responsive afterglow luminescent color-changing film, the color-changing film having phosphorescent molecules with the following structure: .
[0006] The chemical formula of this phosphorescent molecule is C2. 19 H 16 N2O4 has a molecular weight of 336.3470.
[0007] Secondly, the present invention provides a method for preparing the above-mentioned ultraviolet light-responsive afterglow luminescent color-changing film, the preparation steps of which are as follows: 1) Dissolve D-tryptophan in dilute sulfuric acid, then add p-formylbenzoic acid, and reflux and stir at 100℃ for 5 h to obtain substance a;
[0008] Wherein: the structural formula of D-tryptophan is shown in formula (Ⅰ); the structural formula of substance a is shown in formula (Ⅱ); 2) Dissolve substance a obtained in step 1) in a mixed solution of anhydrous methanol and concentrated sulfuric acid, and stir at 75 °C for 12 h to obtain substance b; .
[0009] The structural formula of substance b is shown in formula (Ⅲ); 3) Dissolve substance b obtained in step 2) and sodium hydroxide in a mixed solvent of tetrahydrofuran / water with a volume ratio of 1:1. Stir at room temperature for 9 hours to obtain substance c. .
[0010] The structural formula of substance c is shown in formula (Ⅳ); 4) Preparation of UV-responsive afterglow luminescent color-changing film The substance c obtained in step 3) was dispersed in a PVA aqueous solution, and after ultrasonic treatment for 5 hours, it was allowed to stand for 1 hour to prepare a homogeneous solution. Subsequently, the homogeneous solution was coated onto a quartz glass substrate by drop coating to prepare a thin film.
[0011] Further, the specific preparation method of substance a (crude) in step 1) is as follows: 1.0 g and 4.90 mmol of D-tryptophan were added to a 250 mL round-bottom flask and dissolved in 0.54 mL of 0.2 N dilute sulfuric acid; then 882.14 mg and 5.88 mmol of p-formylbenzoic acid were added, and the mixture was refluxed and stirred at 100 °C for 5 h. After the reaction was completed, the mixture was cooled to room temperature; the pH was adjusted to 6-7 with 2 M sodium hydroxide solution. During this process, the solid gradually precipitated; the obtained solid was collected by filtration to obtain 1.32 g of the crude yellow product shown in formula (II), named (3R)-1-(4-carboxyphenyl)-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole-3-carboxylic acid, with a yield of 80.30%. The product was directly used for subsequent reactions without separation and purification.
[0012] Further, the specific preparation method of substance b in step 2) is as follows: 800 mg and 2.38 mmol of (3R)-1-(4-carboxyphenyl)-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole-3-carboxylic acid are dissolved in a mixed solution of 50.5 mL anhydrous methanol and 0.8 mL concentrated sulfuric acid, and the mixture is stirred at 75 °C for 12 hours; after the reaction solution is cooled to room temperature, it is concentrated by rotary evaporation; the resulting residue is dissolved in 40 mL of water and evaporated using 2M... Neutralize with NaOH aqueous solution, filter and collect the precipitate; purify the crude product by rapid column chromatography (in column chromatography, the eluent is a mixture of ethyl acetate EA and petroleum ether PE, wherein the volume ratio of ethyl acetate EA and petroleum ether PE is 1:4) to obtain 107.13 mg of the yellow solid shown in formula (III), named (3R)-1-(4-methoxycarbonylphenyl)-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole-3-carboxylic acid methyl ester, with a yield of 12.32%. 1 H NMR (400 MHz, DMSO-) d 6) δ 10.37 (s, 1H), 7.97 (d, J = 8.0 Hz, 2H), 7.53 (d, J = 8.4Hz, 2H), 7.46 (d, J = 7.2 Hz, 1H), 7.20 (d, J = 7.6 Hz, 1H), 7.04 – 6.99 (m, 1H), 6.99 – 6.94 (m, 1H), 5.32 (s, 1H), 3.96 – 3.91 (m, 1H), 3.87 (s, 3H), 3.72(s, 3H), 3.09 – 3.03 (m, 1H), 3.00 (s, 1H), 2.90 – 2.81 (m, 1H). Further, the specific preparation method of substance c in step 3) is as follows: 100 mg and 0.27 mmol of (3R)-1-(4-methoxycarbonylphenyl)-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole-3-carboxylic acid methyl ester and 32.93 mg and 0.82 mmol of sodium hydroxide are dissolved in 5 mL of a mixed solvent of tetrahydrofuran / water (tetrahydrofuran / water volume ratio of 1:1); the reaction mixture is stirred at room temperature for 9 hours; after the reaction is completed, tetrahydrofuran is removed by rotary evaporation; the resulting aqueous solution is acidified with 0.1N HCl solution to pH 6-7 to completely precipitate the precipitate, and the solid is collected by vacuum filtration to obtain 42.75 mg of the yellow solid product shown in formula (Ⅳ), named (1S,3R)-1-(4-carboxyphenyl)-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole-3-carboxylic acid, with a yield of 46.3%. 1 H NMR (400 MHz, Methanol- d 4) δ 8.07 (d, J = 8.4 Hz, 2H), 7.54 (d, J = 8.0 Hz, 1H), 7.46 (d, J = 8.0 Hz, 2H), 7.24 (d, J = 8.0 Hz, 1H), 7.14 – 7.10(m, 1H), 7.08 – 7.03 (m, 1H), 6.06 (s, 1H), 4.05 (dd, J = 8.0, 5.6 Hz, 1H), 3.48 (dd, J = 16.4, 5.6 Hz, 1H), 3.34 – 3.29 (m, 1H). 13 C NMR (100 MHz, Methanol-) d 4) δ 173.20, 169.19, 140.48, 133.96, 131.45, 131.29, 123.82,120.67, 119.38, 112.43, 108.99, 56.22, 55.03. MS (ESI + (m / z): [M] + calcd forC 19 H 16 N2O4: 337.1144; found, 337.1185. Further, the specific method for preparing the UV-responsive afterglow luminescent color-changing film in step 4) is as follows: 7.2g of polyvinyl alcohol (PVA) is added to 240mL of deionized water and stirred at 95℃ for 1h to dissolve. After filtration, the resulting 30mg / mL PVA aqueous solution is used for subsequent experiments. (1S,3R)-1-(4-carboxyphenyl)-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole-3-carboxylic acid is dispersed in a 30mg / mL PVA aqueous solution, sonicated for 5h, and then allowed to stand for 1h to prepare a homogeneous solution. Subsequently, the above homogeneous solution is coated onto a 50mm×20mm quartz glass substrate using a drop-coating method to prepare a thin film. After drying at 80℃ for 4h, the UV-responsive afterglow luminescent color-changing film is obtained.
[0013] Thirdly, this invention provides the application of an ultraviolet light-responsive afterglow luminescent color-changing film in the field of anti-counterfeiting. The effects of the ultraviolet light-responsive afterglow luminescent color-changing film are as follows: After drying the film containing the compound molecules, a long afterglow phenomenon can be observed under ultraviolet light excitation (e.g., 275 nm ultraviolet light excitation). The phosphorescence lifetime is up to 3.19 s at room temperature. The phosphorescence excitation dependence phenomenon can be observed by exciting the film with ultraviolet light of different wavelengths. After irradiating the film with ultraviolet lamps of wavelengths of 254 nm, 275 nm, 310 nm and 365 nm and then removing them, the long afterglow luminescence of the film was photographed.
[0014] The advantages of this invention are: the preparation method has simple synthesis steps, high yield, and low cost, and can be applied to the preparation of anti-counterfeiting marks. Attached Figure Description
[0015] Figure 1 This is the phosphorescence spectrum of the ultraviolet light-responsive afterglow luminescent color-changing film of the present invention.
[0016] Figure 2 This is a phosphorescence lifetime diagram of the ultraviolet light-responsive afterglow luminescent color-changing film of the present invention.
[0017] Figure 3 This is a phosphorescence excitation dependence diagram of the ultraviolet light-responsive afterglow luminescent color-changing film of the present invention.
[0018] Figure 4 This is a photograph of the long afterglow of the UV-responsive afterglow luminescent color-changing film of the present invention after being irradiated by a UV lamp. Detailed Implementation
[0019] The implementation of the present invention will be further described below with reference to the accompanying drawings and through embodiments, but the technical solution of the present invention is not limited to the following embodiments.
[0020] This invention provides an ultraviolet light-responsive afterglow luminescent color-changing film, which has phosphorescent molecules with the following structure, wherein the chemical formula of the phosphorescent molecules is C. 19 H 16 N₂O₄, with a molecular weight of 336.3470, has the following molecular structure: .
[0021] The preparation steps of the color-changing film of the present invention are as follows: 1) (3R)-1-(4-carboxyphenyl)-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole-3-carboxylic acid (crude): D-tryptophan (1.0 g, 4.90 mmol) as shown in formula (I) was added to a 250 mL round-bottom flask and dissolved in 0.54 mL of 0.2 N dilute sulfuric acid. Then p-formylbenzoic acid (882.14 mg, 5.88 mmol) was added, and the mixture was refluxed and stirred at 100 °C for 5 h. After the reaction was complete, the mixture was cooled to room temperature. The pH was adjusted to slightly acidic (6-7) with 2 M sodium hydroxide solution. During this process, the solid gradually precipitated. The obtained solid was collected by filtration to give 1.32 g of crude yellow product, with a yield of 80.30%. The obtained (3R)-1-(4-carboxyphenyl)-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole-3-carboxylic acid (crude) structure is shown in Formula (II). The obtained product was directly used for subsequent reactions without separation and purification.
[0022] The reaction formula is: .
[0023] 2) Methyl (3R)-1-(4-methoxycarbonylphenyl)-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole-3-carboxylic acid: 800 mg (2.38 mmol) of (3R)-1-(4-carboxyphenyl)-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole-3-carboxylic acid was dissolved in a mixed solution of anhydrous methanol (50.5 mL) and concentrated sulfuric acid (0.8 mL), and the mixture was stirred at 75 °C for 12 hours. After cooling to room temperature, the reaction solution was concentrated using a rotary evaporator. The resulting residue was dissolved in water (40 mL), neutralized with 2 M NaOH aqueous solution, and the precipitate was collected by filtration. The crude product was purified by rapid column chromatography (using a mixture of ethyl acetate (EA) and petroleum ether (PE) as eluent, with a volume ratio of 1:4) to give a yellow solid (107.13 mg, 12.32%). 1 H NMR (400 MHz, DMSO- d 6) δ 10.37 (s, 1H), 7.97 (d, J= 8.0Hz, 2H), 7.53 (d, J = 8.4 Hz, 2H), 7.46 (d, J = 7.2 Hz, 1H), 7.20 (d, J = 7.6 Hz,1H), 7.04 – 6.99 (m, 1H), 6.99 – 6.94 (m, 1H), 5.32 (s, 1H), 3.96 – 3.91 (m,1H), 3.87 (s, 3H), 3.72 (s, 3H), 3.09 – 3.03 (m, 1H), 3.00 (s, 1H), 2.90 –2.81 (m, 1H). The structure of the obtained (3R)-1-(4-methoxycarbonylphenyl)-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole-3-carboxylic acid methyl ester is shown in Formula (III).
[0024] The reaction formula is: .
[0025] 3) (1S,3R)-1-(4-carboxyphenyl)-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole-3-carboxylic acid: Methyl (3R)-1-(4-methoxycarbonylphenyl)-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole-3-carboxylic acid (100 mg, 0.27 mmol) and sodium hydroxide (32.93 mg, 0.82 mmol) were dissolved in a mixed solvent of tetrahydrofuran / water (5 mL, 1:1, V / V). The reaction mixture was stirred at room temperature for 9 hours. After the reaction was complete, the tetrahydrofuran was removed by rotary evaporation. The resulting aqueous solution was acidified to weakly acidic (pH 6-7) with 0.1 N HCl solution to completely precipitate the solid, which was collected by vacuum filtration to give a yellow solid product (42.75 mg, yield 46.3%). 1 H NMR (400 MHz, Methanol- d 4) δ 8.07 (d, J = 8.4Hz, 2H), 7.54 (d, J = 8.0 Hz, 1H), 7.46 (d, J = 8.0 Hz, 2H), 7.24 (d, J = 8.0 Hz,1H), 7.14 – 7.10 (m, 1H), 7.08 – 7.03 (m, 1H), 6.06 (s, 1H), 4.05 (dd, J= 8.0, 5.6 Hz, 1H), 3.48 (dd, J = 16.4, 5.6 Hz, 1H), 3.34 – 3.29 (m, 1H). 13 C NMR (100MHz, Methanol- d 4) δ 173.20, 169.19, 140.48, 133.96, 131.45, 131.29, 123.82,120.67, 119.38, 112.43, 108.99, 56.22, 55.03. MS (ESI + (m / z): [M] + calcd forC 19 H 16 N2O4: 337.1144; found, 337.1185. The obtained (1S,3R)-1-(4-carboxyphenyl)-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole-3-carboxylic acid structure is shown in formula (Ⅳ).
[0026] The reaction formula is: .
[0027] 4) Preparation of UV-responsive afterglow luminescent color-changing film: 7.2 g of polyvinyl alcohol (PVA) was added to 240 mL of deionized water and stirred at 95 °C for 1 h to dissolve. After filtration, the resulting 30 mg / mL PVA aqueous solution was used for subsequent experiments. (1S,3R)-1-(4-carboxyphenyl)-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole-3-carboxylic acid (chromophore concentration of 20 μg / mL) was dispersed in a 30 mg / mL PVA aqueous solution. After ultrasonic treatment for 5 h and standing for 1 h, a homogeneous solution was prepared. Subsequently, the above homogeneous solution was coated onto a 50 mm × 20 mm quartz glass substrate using a drop-coating method to prepare a thin film. After drying at 80 °C for 4 h, the UV-responsive afterglow luminescent color-changing film was obtained.
[0028] Figure 1 This is the phosphorescence spectrum of the ultraviolet light-responsive afterglow luminescence color-changing film of the present invention. The vertical axis of the figure is the phosphorescence intensity (au), and the horizontal axis is the wavelength (nm). The room temperature phosphorescence spectrum of the color-changing film was tested with 275nm as the excitation wavelength. The results show that it exhibits a strong emission peak at 485nm and the maximum phosphorescence intensity is about 250 (au).
[0029] Figure 2This is a phosphorescence lifetime diagram of the ultraviolet light responsive afterglow luminescence color-changing film of the present invention. The diagram shows that the material can be observed to have a long afterglow phenomenon under ultraviolet light excitation, and the phosphorescence lifetime can reach up to 3.19s at room temperature.
[0030] Figure 3 This is a phosphorescence excitation dependence diagram of the ultraviolet light responsive afterglow luminescent color-changing film of the present invention. The diagram shows that as the excitation wavelength increases from 200 nm to 380 nm, its phosphorescence emission peak shifts from 441 nm to 504 nm, showing a significant redshift.
[0031] Figure 4 This is a phosphorescence excitation dependence diagram of the ultraviolet light-responsive afterglow luminescent color-changing film of the present invention. The diagram shows that it exhibits a distinct long afterglow color after ultraviolet irradiation (254nm, 275nm, 310nm, and 365nm ultraviolet lamps).
[0032] Based on the above embodiments, the present invention provides a fluorescent material and prepares an ultraviolet light-responsive afterglow luminescence color-changing film using the fluorescent material. The resulting film has wide applications and is easy to cut. This method proposes a simple preparation strategy for pure organic room temperature phosphorescent materials with doped PVA films.
[0033] In this invention, the phosphorescent molecules in the doped system are bound by a hydrogen bond network, thereby suppressing the non-radiative transition process of the phosphor and producing room-temperature phosphorescence. After irradiation with ultraviolet light of different wavelengths for one minute, the prepared doped PVA film, with the light source turned off, exhibits blue and green afterglow under dark conditions, suggesting its application in printing and anti-counterfeiting fields. The phosphorescent material and the resulting film of this invention feature a simple preparation route, low cost, long luminescence lifetime, and low production cost, pointing to a direction for further research on organic room-temperature phosphorescent materials.
Claims
1. A UV-responsive afterglow luminescent color-changing film, characterized in that, The color-changing film has phosphorescent molecules with the following structure: The chemical formula of this phosphorescent molecule is C2. 19 H 16 N2O4 has a molecular weight of 336.3470.
2. The method for preparing the ultraviolet light-responsive afterglow luminescent color-changing film according to claim 1, characterized in that, step... as follows: 1) Dissolve D-tryptophan in dilute sulfuric acid, then add p-formylbenzoic acid, and reflux and stir at 100℃ for 5 h to obtain substance a; Wherein: the structural formula of D-tryptophan is shown in formula (Ⅰ); the structural formula of substance a is shown in formula (Ⅱ); 2) Dissolve substance a obtained in step 1) in a mixed solution of anhydrous methanol and concentrated sulfuric acid, and stir at 75 °C for 12 h to obtain substance b; The structural formula of substance b is shown in formula (Ⅲ); 3) Dissolve substance b obtained in step 2) and sodium hydroxide in a mixed solvent of tetrahydrofuran / water with a volume ratio of 1:
1. Stir at room temperature for 9 hours to obtain substance c. The structural formula of substance c is shown in formula (Ⅳ); 4) Disperse the substance c obtained in step 3) in PVA aqueous solution, sonicate for 5 hours and let stand for 1 hour to prepare a homogeneous solution. Then, use the drop coating method to coat the homogeneous solution onto a quartz glass substrate to prepare an ultraviolet light responsive afterglow luminescence color-changing film.
3. The method for preparing the ultraviolet light-responsive afterglow luminescent color-changing film according to claim 2, characterized in that, The specific preparation method of substance a in step 1) is as follows: 1.0 g and 4.90 mmol of D-tryptophan were added to a 250 mL round-bottom flask and dissolved in 0.54 mL of 0.2 N dilute sulfuric acid. Then, 882.14 mg and 5.88 mmol of p-formylbenzoic acid were added, and the mixture was refluxed and stirred at 100 °C for 5 h. After the reaction was completed, the mixture was cooled to room temperature. The pH was adjusted to 6-7 with 2 M sodium hydroxide solution. During this process, the solid gradually precipitated. The obtained solid was collected by filtration to obtain substance a.
4. The method for preparing the ultraviolet light-responsive afterglow luminescent color-changing film according to claim 2, characterized in that, The specific preparation method of substance b in step 2) is as follows: 800 mg and 2.38 mmol of substance a were dissolved in a mixed solution of 50.5 mL anhydrous methanol and 0.8 mL concentrated sulfuric acid, and the mixture was stirred at 75 °C for 12 hours. After the reaction solution was cooled to room temperature, it was concentrated by rotary evaporation. The resulting residue was dissolved in 40 mL of water, neutralized with 2 M NaOH aqueous solution, and the precipitate was collected by filtration. The crude product was purified by rapid column chromatography to obtain substance b.
5. The method for preparing the ultraviolet light-responsive afterglow luminescent color-changing film according to claim 2, characterized in that, The specific preparation method of substance c in step 3) is as follows: 100 mg (0.27 mmol) of substance b and 32.93 mg (0.82 mmol) of sodium hydroxide were dissolved in 5 mL of a tetrahydrofuran / water mixture. The reaction mixture was stirred at room temperature for 9 hours. After the reaction was complete, tetrahydrofuran was removed by rotary evaporation. The resulting aqueous solution was acidified to pH 6-7 with 0.1 N HCl solution to completely precipitate the solid. The solid was collected by vacuum filtration to obtain substance c.
6. The method for preparing the ultraviolet light-responsive afterglow luminescent color-changing film according to claim 2, characterized in that, The specific preparation method of the ultraviolet light-responsive afterglow luminescent color-changing film in step 4) is as follows: 7.2 g of polyvinyl alcohol (PVA) was added to 240 mL of deionized water and stirred at 95 °C for 1 h to dissolve. After filtration, the resulting 30 mg / mL PVA aqueous solution was used for subsequent experiments. Substance c was dispersed in the 30 mg / mL PVA aqueous solution, sonicated for 5 h, and then allowed to stand for 1 h to prepare a homogeneous solution. Subsequently, the above homogeneous solution was coated onto a 50 mm × 20 mm quartz glass substrate using a drop-coating method to prepare a thin film. After drying at 80 °C for 4 h, an ultraviolet light-responsive afterglow luminescent color-changing film was obtained.
7. The method for preparing the ultraviolet light-responsive afterglow luminescent color-changing film according to claim 4, characterized in that, in column chromatography, the eluent is a mixture of ethyl acetate (EA) and petroleum ether (PE), wherein the volume ratio of ethyl acetate (EA) to petroleum ether (PE) is 1:
4.
8. The application of the ultraviolet light-responsive afterglow luminescent color-changing film as described in claim 1 in the field of anti-counterfeiting.