Super-flexible crystal material with fluorescence and crystallization preparation method thereof

Abstract

The invention relates to a fluorescent super-flexible crystal material and a crystallization preparation method thereof, and the method comprises the following steps: firstly, completely dissolving 4-methylaniline in a mixed solution of hydrochloric acid and distilled water to obtain a solution 1; placing the solution 1 in a 100ml (three-necked flask and beaker), and reducing the reaction temperature to 0-5 DEG C; dissolving sodium nitrite in water, dissolving 2-naphthol (the molar weight is slightly lower than that of 4-methylaniline) in a sodium hydroxide solution with the mass fraction of 10% (heating and dissolving) to obtain a solution 2, slowly dropwise adding the sodium nitrite solution into the solution 1, dropwise adding the solution 2 after the starch potassium iodide test paper just turns blue, and continuously stirring for reaction; after the reaction is finished, a sodium hydroxide solution with the mass fraction of 10% is used for adjusting the pH to obtain a product, the product is washed with distilled water till filtrate is neutral, drying is conducted in a vacuum drying box at the temperature of 45 DEG C, the product is obtained, the calculated yield can reach 90% or above, and the fluorescent crystal with the length larger than 0.5 cm and the strain energy reaching 80% and ultrahigh flexibility is cultured.

Description

Technical Field

[0001] This application relates to the field of chemical engineering crystallization technology, specifically to a fluorescent ultra-flexible crystal material and its crystallization preparation method. Background Technology

[0002] Smart responsive materials have become a frontier in materials science research due to their dynamic response to external stimuli. Among them, organic crystal materials combine excellent mechanical flexibility with specific optical functions, showing unique advantages in fields such as flexible electronics, optical devices, and biomedical applications. Elastic fluorescent crystals not only possess the mechanical properties of conventional elastic crystals but also exhibit unique optical characteristics. Traditional crystal materials are generally considered rigid and brittle under external forces, which severely limits their application in flexible devices. However, recent studies have shown that certain organic crystals can exhibit significant elastic deformation capabilities under mechanical stress while maintaining structural and functional integrity.

[0003] Traditional crystal materials are severely limited in their application to flexible devices due to their rigidity and brittleness. Currently, most discovered flexible crystals exhibit bending strain of less than 10%. Elastic fluorescent crystals, as an important branch of smart responsive materials, have achieved synergistic regulation of mechanical properties and optical functions through molecular design and crystal engineering strategies based on π-conjugated systems. Research shows that by optimizing intermolecular non-covalent interactions (such as hydrogen bonds and π-π stacking), excellent elastic deformation capabilities and stimulus-responsive fluorescence properties can be obtained simultaneously.

[0004] To address the aforementioned technical challenges, this invention develops novel flexible functional crystal materials through innovative molecular structure design and optimized crystallization processes. This material system achieves effective control over both microstructure and macroscopic properties by introducing characteristic functional groups to construct a synergistic regulatory network. Experiments have demonstrated that the resulting material maintains excellent optical properties while exhibiting significant deformability and stable stimulus-response characteristics (it only fractures when strain reaches 80%, and does not fracture even after repeated stretching under external force), providing an important material foundation for the development of next-generation flexible optoelectronic devices. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing flexible materials by providing a fluorescent ultra-flexible crystal material and its crystallization preparation method. To achieve the above objectives, the technical solution adopted by the present invention is as follows: A fluorescent ultra-flexible crystal material and its crystallization preparation method are disclosed, with the following specific steps: S1. Prepare an acidic solution of 4-methylaniline under low temperature conditions; 4-Methylaniline and concentrated hydrochloric acid were reacted at a molar ratio of 1:3.5. At room temperature, 4-methylaniline was added to a mixed solution of concentrated hydrochloric acid and water, with a volume ratio of 1:4 for hydrochloric acid and water. The reaction temperature was lowered to 0-5℃ and stirred at a constant temperature for 5-15 minutes to completely dissolve 4-methylaniline, resulting in an acidic solution of 4-methylaniline. S2. At a temperature of 0-5℃, dissolve sodium nitrite in water. The molar ratio of 4-methylaniline to sodium nitrite is 1:1.1. Slowly add the solution dropwise to the acidic solution of 4-methylaniline and allow it to react slowly until the starch-potassium iodide test paper just turns blue. Then stop adding the sodium nitrite solution. S3. With 4-methylaniline slightly in excess of the molar amount of 2-naphthol, dissolve 2-naphthol in a 10% sodium hydroxide solution and heat to 50°C until a clear solution is obtained. S4. Under the temperature conditions of 0-5℃, the clear liquid obtained in S3 is added dropwise to the solution obtained in S2 at a rate of 500uL / min, and the reaction is stirred for 1h. After the reaction is completed, the pH is adjusted to 8-9 using a 10% sodium hydroxide solution. S5. The suspension obtained in S4 is washed with distilled water until the pH of the washing solution is 7. The solid is obtained by vacuum filtration and dried in a vacuum drying oven at 45°C for more than 24 hours to obtain the product (Z)-1-[2-(p-tolyl)hydrazinoyl]naphth-2(1H)-one. S6. Dissolve the obtained product in N,N-dimethylformamide reagent and allow it to slowly evaporate at room temperature to obtain long needle-like crystals with high flexibility and fluorescent properties.

[0006] Furthermore, in the reaction, 4-methylaniline was in slight excess over 2-naphthol, with a ratio of 1.2:1.

[0007] Furthermore, in step S2, the molar ratio of 4-methylaniline to sodium nitrite is 1:1.1, with 4-methylaniline in slight excess. Therefore, the actual amount of sodium nitrite used is 2-naphthol to sodium nitrite at a ratio of 1:1.1.

[0008] Furthermore, steps S1-S4 are all completed during stirring at a speed of 400-700 rpm.

[0009] The beneficial effects of the present invention are as follows: The (Z)-1-[2-(p-tolyl)hydrazinyl]naphthalene-2(1H)-one prepared by the present invention is a novel flexible crystal material. Compared with existing flexible crystal materials, it is subjected to less stress, has a larger strain range, stronger flexibility (strain energy reaches 80%), and the yield can reach more than 90%. Attached Figure Description

[0010] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0011] Figure 1 The XRD pattern of (Z)-1-[2-(p-tolyl)hydrazine]naphthalene-2(1H)-one crystals in a preferred embodiment of the present invention; Figure 2 The 1H NMR spectrum of (Z)-1-[2-(p-tolyl)hydrazine]naphthyl-2(1H)-one crystals in a preferred embodiment of the present invention; Figure 3 A crystal microscope image of (Z)-1-[2-(p-tolyl)hydrazine]naphth-2(1H)-one in a preferred embodiment of the present invention; Figure 4 This is a diagram illustrating the flexible behavior of (Z)-1-[2-(p-tolyl)hydrazine]naphthalene-2(1H)-one crystals in a preferred embodiment of the present invention; Figure 5 The stress-strain curve of (Z)-1-[2-(p-tolyl)hydrazine]naphthalene-2(1H)-one crystal in a preferred embodiment of the present invention is shown. Detailed Implementation

[0012] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0013] A fluorescent ultra-flexible crystal material and its crystallization preparation method are disclosed, with the following specific steps: S1. Prepare an acidic solution of 4-methylaniline under low temperature conditions; 4-Methylaniline and concentrated hydrochloric acid were reacted at a molar ratio of 1:3.5. At room temperature, 4-methylaniline was added to a mixed solution of concentrated hydrochloric acid and water, with a volume ratio of 1:4 for hydrochloric acid and water. The reaction temperature was lowered to 0-5℃ and stirred at a constant temperature for 5-15 minutes to completely dissolve 4-methylaniline, resulting in an acidic solution of 4-methylaniline. S2. At a temperature of 0-5℃, dissolve sodium nitrite in water. The molar ratio of 4-methylaniline to sodium nitrite is 1:1.1. Slowly add the solution dropwise to the acidic solution of 4-methylaniline and allow it to react slowly until the starch-potassium iodide test paper just turns blue. Then stop adding the sodium nitrite solution. S3. With 4-methylaniline slightly in excess of the molar amount of 2-naphthol, dissolve 2-naphthol in a 10% sodium hydroxide solution and heat to 50°C until a clear solution is obtained. S4. Under the temperature conditions of 0-5℃, the clear liquid obtained in S3 is added dropwise to the solution obtained in S2 at a rate of 500uL / min, and the reaction is stirred for 1h. After the reaction is completed, the pH is adjusted to 8-9 using a 10% sodium hydroxide solution. S5. The suspension obtained in S4 is washed with distilled water until the pH of the washing solution is 7. The solid is obtained by vacuum filtration and dried in a vacuum drying oven at 45°C for more than 24 hours to obtain the product (Z)-1-[2-(p-tolyl)hydrazinoyl]naphth-2(1H)-one. S6. Dissolve the obtained product in N,N-dimethylformamide reagent and allow it to slowly evaporate at room temperature to obtain long needle-like crystals with high flexibility and fluorescent properties.

[0014] Furthermore, in the reaction, 4-methylaniline was in slight excess over 2-naphthol, with a ratio of 1.2:1.

[0015] Furthermore, in step S2, the molar ratio of 4-methylaniline to sodium nitrite is 1:1.1, with 4-methylaniline in slight excess. Therefore, the actual amount of sodium nitrite used is 2-naphthol to sodium nitrite at a ratio of 1:1.1.

[0016] Furthermore, steps S1-S4 are all completed during stirring at a speed of 400-700 rpm.

[0017] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below with reference to specific illustrations and embodiments. Example

[0018] 1) Under stirring conditions, 5.14 g of 4-methylaniline (48 mmol) was added at room temperature to a three-necked round-bottom flask containing a mixed solution of 12 mL concentrated hydrochloric acid and 50 mL water; the temperature was lowered to 0-5 °C, and the mixture was stirred at a constant temperature for 30 minutes to completely dissolve or disperse the 5.14 g of 4-methylaniline, resulting in an acidic solution of 4-methylaniline. The stirring speed was 500 rpm. 2) At a temperature of 0-5℃, dissolve 3.0g of sodium nitrite in water. The molar ratio of 4-methylaniline to sodium nitrite is 1:1.1. Slowly add the solution dropwise to the acidic solution of 4-methylaniline and allow it to react slowly until the starch-potassium iodide test paper just turns blue. Then stop adding the sodium nitrite solution. 3) Dissolve 5.77 g of 2-naphthol (40 mmol) in 10 ml of 10% sodium hydroxide solution, heat to 50 °C, and dissolve until a clear solution is obtained; 4) Under the temperature conditions of 0-5℃, the clarified liquid from step (3) is added dropwise to the solution obtained in (2) at a rate of 500uL / min, and the reaction is stirred for 1h. After the reaction is completed, the pH is adjusted to 8-9 using a 10% sodium hydroxide solution. 5) The suspension obtained in (4) was washed with distilled water until the pH of the washing liquid was 7. The solid was obtained by vacuum filtration and dried in a vacuum drying oven at 45°C for more than 24 hours to obtain the product (Z)-1-[2-(p-tolyl)hydrazine]naphthalene-2(1H)-one; 6) Dissolve 10.0 g of the obtained product (Z)-1-[2-(p-tolyl)hydrazinyl]naphth-2(1H)-one in N,N-dimethylformamide reagent and slowly volatilize at room temperature to obtain long needle-like crystals with high flexibility and fluorescent properties.

[0019] The synthesis yielded 95.31% of the product, with a crystallinity of 100% and more than 50% of the crystals being longer than 0.5 cm. The XRD, ¹H NMR, crystal microscopy, crystal flexibility behavior, and stress-strain results of the obtained product are as follows: Figure 1 , 2 As shown in Figures 3, 4, and 5, the XRD and HNMR results show that the prepared (Z)-1-[2-(p-tolyl)hydrazinyl]naphthyl-2(1H)-one has high purity. Microscopic examination, crystal flexibility behavior, and crystal stress-strain curves show that the crystal has high flexibility and will only break when it reaches 80%. Example

[0020] 1) Under stirring conditions, 2.57 g of 4-methylaniline (24 mmol) was added at room temperature to a three-necked round-bottom flask containing a mixed solution of 6 mL concentrated hydrochloric acid and 25 mL water; the temperature was lowered to 0-5 °C and stirred at a constant temperature for 30 minutes to completely dissolve or disperse the 2.57 g of 4-methylaniline, resulting in an acidic solution of 4-methylaniline. The stirring speed was 500 rpm. 2) At a temperature of 0-5℃, dissolve 1.52g of sodium nitrite in water. The molar ratio of 4-methylaniline to sodium nitrite is 1:1.1. Slowly add the solution dropwise to the acidic solution of 4-methylaniline and allow it to react slowly until the starch-potassium iodide test paper just turns blue. Then stop adding the sodium nitrite solution. 3) Dissolve 2.88 g of 2-naphthol (20 mmol) in 8 ml of 10% sodium hydroxide solution, heat to 50°C, and dissolve until a clear solution is obtained; 4) Under the temperature conditions of 0-5℃, the clarified liquid from step (3) is added dropwise to the solution obtained in (2) at a rate of 500uL / min, and the reaction is stirred for 1h. After the reaction is completed, the pH is adjusted to 8-9 using a 10% sodium hydroxide solution. 5) The suspension obtained in (4) was washed with distilled water until the pH of the washing liquid was 7. The solid was obtained by vacuum filtration and dried in a vacuum drying oven at 45°C for more than 24 hours to obtain the product (Z)-1-[2-(p-tolyl)hydrazine]naphthalene-2(1H)-one; 6) Dissolve 4.86 g of the obtained product (Z)-1-[2-(p-tolyl)hydrazinyl]naphth-2(1H)-one in N,N-dimethylformamide reagent and slowly volatilize at room temperature to obtain long needle-like crystals with high flexibility and fluorescent properties.

[0021] The synthesis yielded 92.72% of the product, with a crystallinity of 100% and more than 50% of the crystals being longer than 0.5 cm. The XRD, ¹H NMR, crystal microscopy, crystal flexibility behavior, and stress-strain results of the obtained product are as follows: Figure 1 , 2 As shown in Figures 3, 4, and 5, the XRD and HNMR results show that the prepared (Z)-1-[2-(p-tolyl)hydrazinyl]naphthyl-2(1H)-one has high purity. Microscopic examination, crystal flexibility behavior, and crystal stress-strain curves show that the crystal has high flexibility and will only break when it reaches 80%. Example

[0022] 1) Under stirring conditions, 3.86 g of 4-methylaniline (36 mmol) was added at room temperature to a three-necked round-bottom flask containing a mixed solution of 9 mL concentrated hydrochloric acid and 40 mL water; the temperature was lowered to 0-5 °C and stirred at a constant temperature for 30 minutes to completely dissolve or disperse the 3.86 g of 4-methylaniline, resulting in an acidic solution of 4-methylaniline. The stirring speed was 500 rpm. 2) At a temperature of 0-5℃, dissolve 2.28g of sodium nitrite in water. The molar ratio of 4-methylaniline to sodium nitrite is 1:1.1. Slowly add the solution dropwise to the acidic solution of 4-methylaniline and allow it to react slowly until the starch-potassium iodide test paper just turns blue. Then stop adding the sodium nitrite solution. 3) Dissolve 4.32 g of 2-naphthol (30 mmol) in 10 ml of 10% sodium hydroxide solution, heat to 50 °C, and dissolve until a clear solution is obtained; 4) Under the temperature conditions of 0-5℃, the clarified liquid from step (3) is added dropwise to the solution obtained in (2) at a rate of 500uL / min, and the reaction is stirred for 1h. After the reaction is completed, the pH is adjusted to 8-9 using a 10% sodium hydroxide solution. 5) The suspension obtained in (4) was washed with distilled water until the pH of the washing liquid was 7. The solid was obtained by vacuum filtration and dried in a vacuum drying oven at 45°C for more than 24 hours to obtain the product (Z)-1-[2-(p-tolyl)hydrazine]naphthalene-2(1H)-one; 6) Dissolve 7.44 g of the obtained product (Z)-1-[2-(p-tolyl)hydrazinyl]naphth-2(1H)-one in N,N-dimethylformamide reagent and slowly volatilize at room temperature to obtain long needle-like crystals with high flexibility and fluorescent properties.

[0023] The synthesis yielded 94.66% of the product, with a crystallinity of 100% and more than 50% of the crystals being longer than 0.5 cm. The XRD, ¹H NMR, crystal microscopy, crystal flexibility behavior, and stress-strain results of the obtained product are as follows: Figure 1 , 2 As shown in Figures 3, 4, and 5, the XRD and HNMR results show that the prepared (Z)-1-[2-(p-tolyl)hydrazinyl]naphthyl-2(1H)-one has high purity. Microscopic examination, crystal flexibility behavior, and crystal stress-strain curves show that the crystal has high flexibility and will only break when it reaches 80%. Example

[0024] 1) Under stirring conditions, 1.98 g of 4-methylaniline (18 mmol) was added at room temperature to a three-necked round-bottom flask containing a mixed solution of 5 mL concentrated hydrochloric acid and 20 mL water; the temperature was lowered to 0-5 °C and stirred at a constant temperature for 30 minutes to completely dissolve or disperse the 1.98 g of 4-methylaniline, resulting in an acidic solution of 4-methylaniline. The stirring speed was 500 rpm. 2) At a temperature of 0-5℃, dissolve 1.52g of sodium nitrite in water. The molar ratio of 4-methylaniline to sodium nitrite is 1:1.1. Slowly add the solution dropwise to the acidic solution of 4-methylaniline and allow it to react slowly until the starch-potassium iodide test paper just turns blue. Then stop adding the sodium nitrite solution. 3) Dissolve 2.22 g of 2-naphthol (15 mmol) in 8 ml of 10% sodium hydroxide solution, heat to 50°C, and dissolve until a clear solution is obtained; 4) Under the temperature conditions of 0-5℃, the clarified liquid from step (3) is added dropwise to the solution obtained in (2) at a rate of 500uL / min, and the reaction is stirred for 1h. After the reaction is completed, the pH is adjusted to 8-9 using a 10% sodium hydroxide solution. 5) The suspension obtained in (4) was washed with distilled water until the pH of the washing liquid was 7. The solid was obtained by vacuum filtration and dried in a vacuum drying oven at 45°C for more than 24 hours to obtain the product (Z)-1-[2-(p-tolyl)hydrazine]naphthalene-2(1H)-one; 6) Dissolve 3.79 g of the obtained product (Z)-1-[2-(p-tolyl)hydrazinyl]naphth-2(1H)-one in N,N-dimethylformamide reagent and slowly volatilize at room temperature to obtain long needle-like crystals with high flexibility and fluorescent properties.

[0025] The synthesis yielded 96.44% of the product, with a crystallinity of 100% and more than 50% of the crystals being longer than 0.5 cm. The XRD, ¹H NMR, crystal microscopy, crystal flexibility behavior, and stress-strain results of the obtained product are as follows: Figure 1 , 2 As shown in Figures 3, 4, and 5, the XRD and HNMR results show that the prepared (Z)-1-[2-(p-tolyl)hydrazinoyl]naphthalene-2(1H)-one has high purity. The microscopic examination, crystal flexibility behavior, and crystal stress-strain curves show that the crystal has high flexibility, breaking only when it reaches 80%, indicating high flexibility. Example

[0026] 1) Under stirring conditions, 6.43 g of 4-methylaniline (60 mmol) was added at room temperature to a three-necked round-bottom flask containing a mixed solution of 15 mL concentrated hydrochloric acid and 60 mL water; the temperature was lowered to 0-5 °C, and the mixture was stirred at a constant temperature for 30 minutes to completely dissolve or evenly disperse 6.43 g of 4-methylaniline, resulting in an acidic solution of 4-methylaniline. The stirring speed was 500 rpm. 2) At a temperature of 0-5℃, dissolve 3.75g of sodium nitrite in water. The molar ratio of 4-methylaniline to sodium nitrite is 1:1.1. Slowly add the solution dropwise to the acidic solution of 4-methylaniline and allow it to react slowly until the starch-potassium iodide test paper just turns blue. Then stop adding the sodium nitrite solution. 3) Dissolve 7.21 g of 2-naphthol (50 mmol) in 15 ml of 10% sodium hydroxide solution, heat to 50°C, and dissolve until a clear solution is obtained; 4) Under the temperature conditions of 0-5℃, the clarified liquid from step (3) is added dropwise to the solution obtained in (2) at a rate of 500uL / min, and the reaction is stirred for 1h. After the reaction is completed, the pH is adjusted to 8-9 using a 10% sodium hydroxide solution. 5) The suspension obtained in (4) was washed with distilled water until the pH of the washing liquid was 7. The solid was obtained by vacuum filtration and dried in a vacuum drying oven at 45°C for more than 24 hours to obtain the product (Z)-1-[2-(p-tolyl)hydrazine]naphthalene-2(1H)-one; 6) Dissolve 12.49 g of the obtained product (Z)-1-[2-(p-tolyl)hydrazinyl]naphth-2(1H)-one in N,N-dimethylformamide reagent and slowly volatilize at room temperature to obtain long needle-like crystals with high flexibility and fluorescent properties.

[0027] The synthesis yielded 95.34% of the product, with a crystallinity of 100% and more than 50% of the crystals being longer than 0.5 cm. The XRD, ¹H NMR, crystal microscopy, crystal flexibility behavior, and stress-strain results of the obtained product are as follows: Figure 1 , 2 As shown in Figures 3, 4, and 5, the XRD and HNMR results show that the prepared (Z)-1-[2-(p-tolyl)hydrazinyl]naphthyl-2(1H)-one has high purity. Microscopic examination, crystal flexibility behavior, and crystal stress-strain curves show that the crystal has high flexibility and will only break when it reaches 80%.

[0028] In Examples 1 to 5 above, the (Z)-1-[2-(p-tolyl)hydrazine]naphthalene-2(1H)-one crystals prepared exhibited characteristic peaks in their X-ray powder diffraction patterns at diffraction angles of 2θ = 7.6 ± 0.1, 12.6 ± 0.1, 13.6 ± 0.1, 15.4 ± 0.1, 19.6 ± 0.1, 25.0 ± 0.1, 26.8 ± 0.1, 27.5 ± 0.1, and 46.7 ± 0.1 degrees. Figure 1 As shown.

[0029] In Examples 1 to 5 above, the (Z)-1-[2-(p-Tolyl)hydrazine]naphthalene-2(1H)-one crystals prepared had the following NMR spectra (400 MHz, dimethyl sulfoxide): δ / ppm = 15.61 (s, 1H), 8.59 (s, 1H), 7.96 (s, 1H), 7.81 (s, 3H), 7.63 (s, 1H), 7.47 (s, 1H), 7.38 (s, 2H), 7.02 (s, 1H), 2.38 (s, 3H). Figure 2 As shown.

[0030] In Examples 1 to 5 above, the (Z)-1-[2-(p-tolyl)hydrazine]naphthalene-2(1H)-one crystals prepared exhibit extremely high flexibility, recovering their shape even after repeated compression and deformation, with a macroscopic strain reaching 80% fracture rate. Figure 3 As shown in Figures 4 and 5.

[0031] In summary, the (Z)-1-[2-(p-tolyl)hydrazinyl]naphthalene-2(1H)-one crystal prepared by this invention is a novel flexible material with high flexibility, macroscopic strain up to 80%, simple preparation process, and high yield, reaching over 90%, making it suitable for dynamic applications such as flexible electronics and wearable devices.

[0032] The ultra-flexible crystal material and its crystallization preparation method disclosed and proposed in this invention can be implemented by those skilled in the art by appropriately changing the raw materials, process parameters, and other aspects, based on the content of this document. The methods and products of this invention have been described through preferred embodiments. Those skilled in the art can obviously modify or appropriately change and combine the methods and products described herein without departing from the content, spirit, and scope of this invention to achieve the technology of this invention. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art, and they are all considered to be included within the spirit, scope, and content of this invention.

Claims

1. A fluorescent ultraflexible crystal material and its crystallization preparation method, characterized in that, Includes the following steps: S1. Prepare an acidic solution of 4-methylaniline under low temperature conditions; 4-Methylaniline and concentrated hydrochloric acid were reacted at a molar ratio of 1:3.

5. At room temperature, 4-methylaniline was added to a mixed solution of concentrated hydrochloric acid and water, with a volume ratio of 1:4 for hydrochloric acid and water. The reaction temperature was lowered to 0-5℃ and stirred at a constant temperature for 5-15 minutes to completely dissolve 4-methylaniline, resulting in an acidic solution of 4-methylaniline. S2. At a temperature of 0-5℃, dissolve sodium nitrite in water. The molar ratio of 4-methylaniline to sodium nitrite is 1:1.

1. Slowly add the solution dropwise to the acidic solution of 4-methylaniline and allow it to react slowly until the starch-potassium iodide test paper just turns blue. Then stop adding the sodium nitrite solution. S3. With 4-methylaniline slightly in excess of the molar amount of 2-naphthol, dissolve 2-naphthol in a 10% sodium hydroxide solution and heat to 50°C until a clear solution is obtained. S4. Under the temperature conditions of 0-5℃, the clear liquid obtained in S3 is added dropwise to the solution obtained in S2 at a rate of 500uL / min, and the reaction is stirred for 1h. After the reaction is completed, the pH is adjusted to 8-9 using a 10% sodium hydroxide solution. S5. The suspension obtained in S4 is washed with distilled water until the pH of the washing solution is 7. The solid is obtained by vacuum filtration and dried in a vacuum drying oven at 45°C for more than 24 hours to obtain the product (Z)-1-[2-(p-tolyl)hydrazinoyl]naphth-2(1H)-one. S6. Dissolve the obtained product in N,N-dimethylformamide reagent and allow it to slowly evaporate at room temperature to obtain long needle-like crystals with high flexibility and fluorescent properties.

2. The fluorescent ultra-flexible crystal material and its crystallization preparation method according to claim 1, characterized in that, The 4-methylaniline was in slight excess of 2-naphthol, with a ratio of 1.2:

1.

3. The fluorescent ultra-flexible crystal material and its crystallization preparation method according to claim 1, characterized in that, In step S2, the molar ratio of 4-methylaniline to sodium nitrite is 1:1.1, with 4-methylaniline in slight excess. Therefore, the actual amount of sodium nitrite used is 2-naphthol to sodium nitrite at a ratio of 1:1.

1.

4. The fluorescent ultraflexible crystal material and its crystallization preparation method according to claim 1, characterized in that, Steps S1-S4 are all completed while stirring at a speed of 400-700 rpm.

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