Flexible fluorescent sensor based on perylene diimide derivatives for detecting benzene vapor

Abstract

The present invention relates to a flexible fluorescent sensor based on a perylene diimide derivative for detecting benzene series vapor, belonging to the technical field of fluorescent sensors. In the flexible fluorescent sensor, a perylene diimide derivative is used as a fluorescent probe, and the perylene diimide derivative is HO-PDI-OH or UPy-PDI-UPy. The fluorescent probe HO-PDI-OH or UPy-PDI-UPy is doped into a polyurethane matrix to obtain a flexible fluorescent sensor. The flexible fluorescent sensor prepared by the present invention can achieve specific detection of benzene series vapor. Utilizing the flexible fluorescent sensor to detect benzene series vapor, the sensor has the characteristics of luminescent color change, visual recognition, good portability, high sensitivity, rapid response, and easy operation, and has potential application prospects in the field of benzene series detection.

Description

Technical Field

[0001] The present invention belongs to the technical field of fluorescence sensors, and in particular relates to a flexible fluorescence sensor based on perylene diimide derivatives for detecting benzene series vapor. Background Art

[0002] Against the backdrop of rapid global manufacturing development, coupled with the assistance of artificial intelligence, the industrialization process has been accelerated, leading to an annual increase in the use of BTEX as a basic chemical raw material. However, due to their volatility and biotoxicity, BTEX poses a potential threat to human health and the environment. Their emissions and leakage have caused global concerns about the living environment and public health. Therefore, it is particularly important to develop efficient, sensitive, and accurate BTEX detection methods to monitor BTEX concentrations in the environment and ensure public safety. Although traditional detection methods such as gas chromatography and liquid chromatography have high accuracy, they often require complex sample pretreatment and expensive equipment, which limits their practical application.

[0003] Organic fluorescence sensors can be used to monitor benzene compounds in air and water, helping to track pollution sources and assess environmental quality. In industrial production, particularly in the petrochemical and coatings industries, organic fluorescence sensors can detect benzene compound concentrations in real time, preventing leaks and accidents, and typically exhibit high sensitivity. Organic small molecule fluorescence sensors offer the advantages of high sensitivity and real-time detection, but these small molecule materials are often used for detection in solutions, resulting in poor portability for vapor detection. Furthermore, these sensors often manifest as changes in fluorescence intensity, making it difficult to visually identify benzene vapors. Summary of the Invention

[0004] The present invention aims to provide a flexible fluorescent sensor based on perylene diimide derivatives for detecting benzene series vapors. Two fluorescent probes based on perylene diimide derivatives were synthesized, and a polyurethane-based flexible fluorescent sensor based on these fluorescent probes was prepared. This sensor, which can be used to detect benzene series vapors, exhibits color change, visual recognition, portability, high sensitivity, rapid response, and ease of operation, showing potential applications in the field of benzene series detection.

[0005] The technical problem to be solved by the present invention is: Organic small molecule fluorescence sensors have the advantages of high sensitivity and real-time detection, but these small molecule materials are mostly used for detection in solutions, have poor portability in vapor detection, and are mostly manifested as changes in fluorescence intensity, making it difficult to achieve naked-eye identification of benzene vapors.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A flexible fluorescent sensor based on a perylene diimide derivative for detecting benzene vapor, wherein the perylene diimide derivative is a fluorescent probe, and the structure of the perylene diimide derivative is shown in formula (I):

[0008] Formula (I);

[0009] In the formula (I), R is a hydroxyl group, a hydroxyl derivative, 2-ureido-6-methylpyrimidin-4(1H)-one or a 2-ureido-6-methylpyrimidin-4(1H)-one derivative.

[0010] When R is a hydroxyl group or a hydroxyl derivative, the perylene diimide derivative is HO-PDI-OH.

[0011] When R is 2-ureido-6-methylpyrimidin-4(1H)-one or a derivative thereof, the perylene diimide derivative is UPy-PDI-UPy.

[0012] Furthermore, the structure of HO-PDI-OH is shown in formula (II):

[0013] Formula (II).

[0014] Furthermore, the preparation method of HO-PDI-OH comprises the following steps:

[0015] Under nitrogen protection, 1-amino-3,6,9-trioxa-11-undecanol, 3,4,9,10-perylenetetracarboxylic dianhydride and triethylamine were dissolved in organic solvent 1 to react to obtain a brown solid HO-PDI-OH.

[0016] Furthermore, the organic solvent 1 includes at least one of N,N-dimethylformamide and dimethyl sulfoxide.

[0017] Furthermore, the reaction temperature is 140-160° C., and the reaction time is 3-5 h.

[0018] Furthermore, the molar ratio of 1-amino-3,6,9-trioxa-11-undecanol, 3,4,9,10-perylenetetracarboxylic dianhydride and triethylamine is (2-3):(1-2):(32-39).

[0019] Furthermore, the usage ratio of the 1-amino-3,6,9-trioxa-11-undecanol and the organic solvent 1 is (3-4) mmol: (10-12) mL.

[0020] Further, the synthetic route of HO-PDI-OH is as follows:

[0021] .

[0022] Furthermore, the structure of UPy-PDI-UPy is shown in formula (III):

[0023] Formula (III).

[0024] Furthermore, the preparation method of UPy-PDI-UPy comprises the following steps:

[0025] A1. Dissolve 2-amino-6-methylpyrimidin-4(1H)-one and N,N-carbonyldiimidazole in N,N-dimethylformamide (DMF) to obtain UPy-Imidazole. Then, dissolve UPy-Imidazole and ethanolamine in tetrahydrofuran (THF) to obtain UPy-OH. Finally, dissolve UPy-OH in hexamethylene diisocyanate to obtain the target product UPy-NCO.

[0026] A2. Under nitrogen protection, 1-amino-3,6,9-trioxa-11-undecanol, 3,4,9,10-perylenetetracarboxylic dianhydride (PDI), and triethylamine were dissolved in organic solvent 1 to react to obtain a brown solid HO-PDI-OH.

[0027] A3. Under nitrogen protection, HO-PDI-OH, UPy-NCO and dibutyltin dilaurate (DBTDL) were dissolved in organic solvent 2 to react to obtain brown solid UPy-PDI-UPy.

[0028] Furthermore, in step A3, the organic solvent 2 includes at least one of N,N-dimethylformamide and dimethyl sulfoxide.

[0029] Furthermore, in step A3, the reaction temperature is 60-80° C., and the reaction time is 2-3 h.

[0030] Furthermore, in step A3, the usage ratio of HO-PDI-OH, UPy-NCO and organic solvent 2 is (1-2) mmol: (3-5) mmol: (40-50) mL.

[0031] Furthermore, the synthetic route of UPy-PDI-UPy is as follows:

[0032]

[0033] A method for preparing a flexible fluorescent sensor based on a perylene diimide derivative for detecting benzene series vapor comprises the following steps:

[0034] Step 1: Add polytetrahydrofuran, 1,6-diisocyanate hexane and dibutyltin dilaurate to dry tetrahydrofuran to obtain a mixture, stir the mixture under nitrogen protection, cool the mixture to room temperature after the reaction, add n-hexane thereto, collect the precipitate, wash and dry it to obtain a blank polyurethane matrix;

[0035] Step 2: Mix a blank polyurethane matrix with a perylene diimide derivative, add tetrahydrofuran, and heat until completely dissolved. Pour the solution into a polytetrafluoroethylene mold, let it stand at room temperature overnight, and vacuum dry to obtain a flexible fluorescent sensor.

[0036] Furthermore, in step 2, the mass ratio of the perylene diimide derivative to the polyurethane matrix is (0.010-0.020):3.

[0037] Furthermore, the specific reaction route of the polyurethane matrix is as follows:

[0038]

[0039] Specifically, the two fluorescent probes provided by the present invention exhibit a gradual red-shift in fluorescence color as concentration increases in solution, achieving a transition from monomers to excimers and even aggregates. In powder form, both probes exhibited a fluorescent response to petroleum ether, benzene, dichloromethane, toluene, and xylene solvent vapors. HO-PDI-OH exhibited a predominantly increased fluorescence intensity, while UPy-PDI-UPy exhibited a predominantly blue-shift in fluorescence wavelength. Benzene vapor produced the most pronounced blue-shift in fluorescence, enabling specific recognition of benzene vapor through a transition from orange-red to orange-yellow light.

[0040] Fluorescence spectra reveal that the HO-PDI-OH molecules in the sensor, based on the HO-PDI-OH fluorescent probe, exist in a variety of forms: aggregates, excimers, and monomers. Compared to the powder state, the degree of probe aggregation is reduced, demonstrating that the polyurethane matrix effectively modulates the aggregation state of the probe molecules and that its spatial confinement enhances their dispersion. The sensor was exposed to benzene, toluene, xylene, chloroform, and petroleum ether vapors, respectively. The solvent molecules increased the distance between the probe molecules and reduced their aggregation. From petroleum ether to benzene, the sensor's emission color gradually shifted from orange-red to yellow, demonstrating specific detection of benzene. Fluorescence spectra of the sensor after exposure to benzene vapor for varying durations revealed that the process of benzene molecules penetrating the polyurethane matrix and dissociating the fluorescent probe HO-PDI-OH aggregates reaches equilibrium in a relatively short time, confirming the sensor's rapid detection capabilities.

[0041] In sensors based on the UPy-PDI-UPy fluorescent probe, the fluorescent probe UPy-PDI-UPy exists primarily in monomers, excimer complexes, and aggregates, with the proportion of aggregates significantly lower than that of the probe HO-PDI-OH in the sensor. Sensors containing the fluorescent probe UPy-PDI-UPy were fumigated with petroleum ether, dichloromethane, xylene, toluene, and benzene vapors. While the spectrum remained largely stable under petroleum ether vapor, the remaining solvents all exhibited the ability to dissociate UPy-PDI-UPy molecular aggregates. Fluorescence images of the sensor also clearly show changes in luminescence color, with the sensor's luminescence gradually transitioning from an initial orange-yellow to bright yellow and yellow-green, and exhibiting a bright green emission in benzene vapor, demonstrating significant specific recognition of benzene vapor. Compared to sensors based on HO-PDI-OH, the sensor exhibits higher detection accuracy, more pronounced recognition, and a faster response.

[0042] Beneficial effects of the present invention:

[0043] In the technical solution of the present invention, two probe molecules HO-PDI-OH and UPy-PDI-UPy are physically doped into a polyurethane matrix respectively. The spatial confinement effect provided by the polyurethane polymer chain and the probe molecule end group is utilized. The prepared flexible fluorescent sensor shows a significant decrease in the luminescence intensity of the aggregate under the action of solvent vapor. The luminescent color of the fluorescent sensor gradually blue-shifts in the order of petroleum ether, dichloromethane, xylene, toluene, and benzene, achieving specific detection of benzene vapor. Among them, the sensor luminescent color change based on UPy-PDI-UPy has a higher degree of recognition and a shorter response time. The flexible fluorescent sensor of the present invention is used to detect benzene vapor, which has the characteristics of luminescent color change, visual recognition, good portability, high sensitivity, rapid response and easy operation, and has potential application prospects in the field of benzene detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 The fluorescence spectra of HO-PDI-OH prepared in Example 1 at different concentrations in dichloromethane solution;

[0045] Figure 2 The curve showing the relationship between the fluorescence intensity ratio of the HO-PDI-OH excimer complex and the monomer luminescence and the solution concentration prepared in Example 1;

[0046] Figure 3 The fluorescence spectra of UPy-PDI-UPy prepared in Example 2 at different concentrations in dichloromethane solution;

[0047] Figure 4The curve showing the relationship between the fluorescence intensity ratio of the UPy-PDI-UPy excimer complex and the monomer and the solution concentration prepared in Example 2;

[0048] Figure 5 Fluorescence spectra of HO-PDI-OH prepared in Example 1 fumigated with different solvent vapors;

[0049] Figure 6 The following are the corresponding photographs of HO-PDI-OH prepared in Example 1 after fumigation with different solvent vapors under fluorescent light and ultraviolet light;

[0050] Figure 7 Fluorescence spectra of UPy-PDI-UPy prepared in Example 2 after fumigation with different solvent vapors;

[0051] Figure 8 These are the corresponding photographs of UPy-PDI-UPy prepared in Example 2 after fumigation with different solvent vapors under fluorescent light and ultraviolet light;

[0052] Figure 9 Fluorescence spectra of the flexible fluorescent sensor S1 prepared in Example 3 under the action of different solvent fumigations;

[0053] Figure 10 Fluorescence photos of the flexible fluorescent sensor S1 prepared in Example 3 under the action of different solvent fumigations;

[0054] Figure 11 The fluorescence spectra of the flexible fluorescent sensor S1 prepared in Example 3 at different times under the action of benzene solvent fumigation;

[0055] Figure 12 Fluorescence spectra of the flexible fluorescent sensor S2 prepared in Example 4 under the action of different solvent fumigations;

[0056] Figure 13 Fluorescence photos of the flexible fluorescent sensor S2 prepared in Example 4 under the action of different solvent fumigations;

[0057] Figure 14 These are fluorescence spectra of the flexible fluorescent sensor S2 prepared in Example 4 at different times under the action of benzene solvent fumigation. DETAILED DESCRIPTION

[0058] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0059] Example 1. This example provides a method for preparing HO-PDI-OH, comprising the following steps:

[0060] Under nitrogen, 1-amino-3,6,9-trioxa-11-undecanol (2.6 g, 13.5 mmol), 3,4,9,10-perylenetetracarboxylic dianhydride (2.2 g, 5.6 mmol), and triethylamine (25 mL, 180 mmol) were dissolved in dry DMSO (50 mL). The mixture was stirred at 150°C for 4 h and then cooled to 80°C. A mixture of 10% hydrochloric acid (600 mL) and methanol (300 mL) was then added to the reaction solution. Stirring was continued at 60°C for 2 h, and the mixture was cooled to room temperature, allowed to stand, and filtered. The filter residue was dissolved in chloroform, washed with deionized water, dried over anhydrous magnesium sulfate, and filtered. The solvent was evaporated under reduced pressure, and the crude product was purified by column chromatography (stationary phase: neutral alumina; eluent: dichloromethane / methanol = 5 / 1) and recrystallized from n-hexane to obtain 3.6 g of HO-PDI-OH as a brown solid with a yield of 86%. Its H NMR spectrum data are as follows: 1 HNMR (400MHz, DMSO-d6): δ7.59(t,J=10.7Hz,8H), 4.59(t,J=5.5Hz,2H), 3.77-3.39(m,32H).

[0061] like Figure 1 、 2 As shown in the figure, the fluorescent probe HO-PDI-OH in dichloromethane solution, with the increase of concentration, the existence form of the probe molecule changes from monomer to excimer, and the emission color changes from (yellow) green to yellow, which proves that in low concentration solution, the probe mainly exists in the form of single molecule, while in high concentration solution, it exists in the form of excimer or even multi-molecule aggregate. Figure 5 、 6 As shown in the figure, after the probe HO-PDI-OH powder is fumigated with solvent vapor, the fluorescence intensity increases in the order of petroleum ether (PE), benzene (BZ), dichloromethane (MC), toluene (TL) to xylene (XY), while the spectral wavelength remains basically unchanged, indicating that the probe HO-PDI-OH powder can detect benzene vapor by changing the luminescence intensity.

[0062] Example 2. This example provides a method for preparing UPy-PDI-UPy, comprising the following steps:

[0063] 2-Amino-6-methylpyrimidin-4(1H)-one (6 g, 0.048 mol) and N,N'-carbonyldiimidazole (9.4 g, 0.058 mol) were dissolved in DMF (110 mL) and reacted at 90°C under nitrogen for 5 hours. After the reaction, the mixture was cooled to room temperature, 150 mL of acetone was added as a precipitant, and the mixture was allowed to stand for 2 hours. The residue was filtered, washed with acetone, and dried in a vacuum oven at 50°C to obtain the desired product, Upy-Imidazole, as a white solid (7.8 g, 74.1% yield). It was used directly in the subsequent step.

[0064] UPy-Imidazole (6 g, 0.027 mol) and ethanolamine (2.5 g, 0.041 mol) were dissolved in THF (120 mL) and reacted at 25°C under a nitrogen atmosphere for 3 hours. After the reaction, the reaction solution was concentrated, and 400 mL of distilled water was added as a precipitant. The mixture was allowed to stand for half an hour. The residue was filtered, washed sequentially with deionized water and acetone, and dried in a vacuum oven at 50°C to obtain the desired product, UPy-OH.

[0065] UPy-OH (1.5 g, 7 mmol) was dissolved in 1,6-diisocyanate (HDI) (15 mL) and heated to 90°C under a nitrogen atmosphere for 24 hours. After completion of the reaction, the mixture was cooled to room temperature and precipitated with 100 mL of ethyl acetate. The mixture was allowed to stand for half an hour and then filtered. The residue was washed sequentially with toluene and acetone. The mixture was then dried in a vacuum oven at 50°C to obtain the desired product, UPy-NCO.

[0066] Under nitrogen, the fluorescent probe HO-PDI-OH (1.00 g, 1.3 mmol), UPy-NCO (1.28 g, 3.25 mmol), and DBTDL (83 μL) were dissolved in DMF (40 mL). The mixture was heated to 70°C for 2 h. The mixture was filtered, and the residue was recrystallized from chloroform / n-hexane to obtain 1.76 g of UPy-PDI-UPy, a tan solid, in a 90% yield. Its H NMR spectrum data are as follows: 1 HNMR (400MHz, CDCl3): δ13.12(s,2H),12.90(s,2H),11.75(s,2H),10.24(s,1H),10.10(s,1H),8.68 -8.41(m,8H),5.83(s,2H),4.51-4.43(m,4H),3.95-3.55(m,36H),2.23(s,6H),0.94-0.83(m,16H).

[0067] like Figure 3 、 4As shown in the figure, the fluorescent probe UPy-PDI-UPy in dichloromethane solution changes from monomer to excimer as the concentration increases. The emission color changes from (yellow) green to yellow, proving that the probe exists mainly in the form of a single molecule in low concentration solution, while in the form of an excimer or even a multi-molecule aggregate in high concentration solution. Figure 7 、 8 As shown, under the action of solvent vapor, the luminescence wavelength of UPy-PDI-UPy powder undergoes a significant blue shift in the order of petroleum ether, dichloromethane, toluene, xylene, and finally benzene. The powder fumigated with benzene vapor exhibits the highest luminescence intensity and the most pronounced blue shift, demonstrating clear specific recognition of benzene vapor. Fluorescence images of the samples also clearly show that the luminescence color of the samples fumigated with benzene vapor turns orange-yellow, a noticeable difference visible to the naked eye compared to samples fumigated with other solvent vapors, demonstrating specific recognition of benzene.

[0068] Example 3: This example provides a method for preparing a flexible fluorescent sensor S1, comprising the following steps:

[0069] Step 1: To dry tetrahydrofuran (10 mL), add polytetrahydrofuran (Mn = 650, 1.95 g, 3 mmol), DBTDL (30 μL), and HDI (0.5 mL, 3.02 mmol) to obtain a mixture. Under nitrogen, stir the mixture at 60°C for 20 hours. After cooling to room temperature, add n-hexane (200 mL) as a precipitant. The precipitate is collected, washed with n-hexane, and dried under vacuum to obtain a blank polyurethane matrix (PU).

[0070] Step 2: Mix the polyurethane matrix (3.0 g) with the fluorescent probe HO-PDI-OH (0.015 g) prepared in Example 1, add tetrahydrofuran (3 mL), and heat until completely dissolved. Pour the solution into a polytetrafluoroethylene mold (3.0 × 1.0 × 0.2 cm 3 ) and allowed to stand at room temperature overnight to allow the solvent to evaporate slowly. The obtained sample was then vacuum dried for 24 hours to obtain a flexible fluorescent sensor S1.

[0071] like Figure 9 As shown in the figure, the fluorescent probe HO-PDI-OH is loaded into the polyurethane matrix. The emission peak of sensor S1 is located at 645nm, and there are two shoulder peaks located at 589 and 548nm respectively. This shows that the existence forms of the probe HO-PDI-OH molecules include aggregation, excimer and monomer forms. The polyurethane matrix can effectively regulate the aggregation state of the probe molecules, and the spatial confinement effect it provides can improve the dispersion of the molecules. Figure 10As shown in the figure, from petroleum ether to benzene, the luminescence color of S1 gradually changes from orange-red to yellow, achieving specific detection of benzene. Figure 11 As shown, the fluorescence spectrum changes after fumigation in benzene vapor for different lengths of time showed that the fluorescence spectrum reached equilibrium in a relatively short time, verifying the fast detection characteristics of the sensor.

[0072] Example 4: This example provides a method for preparing a flexible fluorescent sensor S2, comprising the following steps:

[0073] Step 1: To dry tetrahydrofuran (10 mL), add polytetrahydrofuran (Mn = 650, 1.95 g, 3 mmol), DBTDL (30 μL), and HDI (0.5 mL, 3.02 mmol) to obtain a mixture. Under nitrogen, stir the mixture at 60°C for 20 hours. After cooling to room temperature, add n-hexane (200 mL) as a precipitant. The precipitate is collected, washed with n-hexane, and dried under vacuum to obtain a blank polyurethane matrix (PU).

[0074] Step 2: Mix the polyurethane matrix (3.0 g) with the fluorescent probe UPy-PDI-UPy (0.015 g) prepared in Example 2, add tetrahydrofuran (3 mL), and heat until completely dissolved. Pour the solution into a polytetrafluoroethylene mold (3.0 × 1.0 × 0.2 cm 3 ) and allowed to stand at room temperature overnight to allow the solvent to evaporate slowly. The obtained sample was then vacuum dried for 24 hours to obtain a flexible fluorescent sensor S2.

[0075] like Figure 12 As shown in Figure 2, the fluorescent probe UPy-PDI-UPy exists in the form of monomers, excimer complexes, and aggregates in S2. Compared with sensor S1, the relative intensity of the fluorescent probe monomer luminescence peak in S2 is significantly enhanced, and the relative intensity of the aggregate luminescence is significantly weakened. Figure 13 As shown in the figure, under the action of solvent vapor, the change in luminescence color can be clearly observed from the fluorescence photos of the sensor. The luminescence of sensor S2 gradually transitions from the initial orange-yellow to bright yellow and yellow-green, and shows bright green luminescence in benzene vapor, showing obvious specific recognition of benzene vapor. For detection, the recognition is higher and the recognition effect is more obvious. Figure 14 As shown, through the time-dependent fluorescence spectrum, it can be found that the fluorescence spectrum of sensor S2 under the action of benzene vapor basically reaches equilibrium after 3 minutes, and the detection speed is faster.

[0076] Throughout the specification, references to terms such as "one embodiment," "example," or "specific example" indicate that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0077] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the described specific embodiments or replace them in similar ways. As long as they do not deviate from the invention or exceed the scope defined by the claims, they should all fall within the scope of protection of the present invention.

Claims

1. Application of a perylene diimide derivative-based flexible fluorescent sensor in the detection of benzene series vapor, characterized by: The method for preparing the flexible fluorescent sensor comprises the following steps: Step 1: Add polytetrahydrofuran, 1,6-diisocyanate hexane and dibutyltin dilaurate to dry tetrahydrofuran to obtain a mixture, stir the mixture under nitrogen protection, cool the mixture to room temperature after the reaction, add n-hexane thereto, collect the precipitate, wash and dry it to obtain a blank polyurethane matrix; Step 2: Mix a blank polyurethane matrix with a perylene diimide derivative, add tetrahydrofuran, and heat until completely dissolved. Pour the solution into a polytetrafluoroethylene mold, let it stand at room temperature overnight, and vacuum dry to obtain a flexible fluorescent sensor. The perylene diimide derivative is HO-PDI-OH, and its structure is shown in formula (II): Formula (II); Alternatively, the perylene diimide derivative is UPy-PDI-UPy, and its structure is shown in formula (III): Formula (III); The preparation method of the UPy-PDI-UPy comprises the following steps: A1. Dissolving 2-amino-6-methylpyrimidin-4(1H)-one and N,N-carbonyldiimidazole in N,N-dimethylformamide to obtain UPy-Imidazole. Then, dissolving UPy-Imidazole and ethanolamine in tetrahydrofuran to obtain UPy-OH. Finally, dissolving UPy-OH in hexamethylene diisocyanate to obtain the target product UPy-NCO. A2. Under nitrogen protection, 1-amino-3,6,9-trioxa-11-undecanol, 3,4,9,10-perylenetetracarboxylic dianhydride, and triethylamine were dissolved in organic solvent 1 to react to obtain a brown solid HO-PDI-OH; A3. Under nitrogen protection, HO-PDI-OH, UPy-NCO and dibutyltin dilaurate were dissolved in organic solvent 2 to react to obtain UPy-PDI-UPy as a brown solid.

2. The use of the perylene diimide derivative-based flexible fluorescent sensor in the detection of benzene series vapor according to claim 1, characterized in that: The organic solvent 1 is selected from at least one of N,N-dimethylformamide and dimethyl sulfoxide; the reaction temperature is 140-160° C., and the reaction time is 3-5 hours.

3. The use of the perylene diimide derivative-based flexible fluorescent sensor in the detection of benzene series vapor according to claim 1, characterized in that: The molar ratio of the 1-amino-3,6,9-trioxa-11-undecanol, 3,4,9,10-perylenetetracarboxylic dianhydride and triethylamine is (2-3):(1-2):(32-39); the amount ratio of the 1-amino-3,6,9-trioxa-11-undecanol and the organic solvent 1 is (3-4) mmol:(10-12) mL.

4. The use of the perylene diimide derivative-based flexible fluorescent sensor in the detection of benzene series vapor according to claim 1, characterized in that: In the step A3, the organic solvent 2 is selected from at least one of N,N-dimethylformamide and dimethyl sulfoxide, the reaction temperature is 60-80° C., and the reaction time is 2-3 hours.

5. The use of the perylene diimide derivative-based flexible fluorescent sensor in the detection of benzene series vapor according to claim 1, characterized in that: In step A3, the usage ratio of HO-PDI-OH, UPy-NCO and organic solvent 2 is (1-2) mmol: (3-5) mmol: (40-50) mL.

6. Use of the perylene diimide derivative-based flexible fluorescent sensor in the detection of benzene series vapor according to claim 1, characterized in that: The mass ratio of the perylene diimide derivative to the polyurethane matrix is (0.010-0.020):3.

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