Polydiphenylacetylene derivative capable of rapidly detecting nitrobenzene explosives as well as synthesis method and application of polydiphenylacetylene derivative

Abstract

The invention discloses a polydiphenylacetylene derivative capable of rapidly detecting nitrobenzene explosives as well as a synthesis method and application of the polydiphenylacetylene derivative. A polydiphenylacetylene derivative with abundant active sites and extremely strong electron donating ability is designed aiming at the electron-deficient characteristic of nitrobenzene explosives so as to achieve the purpose of rapidly and accurately detecting the nitrobenzene explosives, and an ultrathin fluorescent polymer sensing probe is designed, so that an analyte can permeate the whole film more easily, and a good sensing effect is achieved. The synthesized polydiphenylacetylene derivative fluorescent probe is high in fluorescence intensity, high in detection sensitivity and high in detection speed.

Description

Technical Field

[0001] The present invention relates to the field of polymer fluorescent material sensors, and particularly relates to a polydiphenylacetylene derivative capable of rapidly detecting nitrobenzene explosives, a synthesis method thereof, and an application thereof. Background Art

[0002] Currently, the most common explosives are mainly divided into the following three categories: peroxides, diazonium salt compounds, and nitrobenzene compounds. Among them, nitrobenzene explosives are the most widely used. Poly-nitro aromatic hydrocarbon compounds have extremely strong explosiveness. Therefore, the detection of poly-nitrobenzene explosives such as 2,4,6-trinitrotoluene (TNT), nitrobenzene (NB), p-nitrotoluene (NT), 2,6-dinitrotoluene (DNMT), and 2,4,6-trinitrophenol (PA) is particularly important. The detection techniques for nitrobenzene explosives include chromatography-mass spectrometry, colorimetry, electrochemistry, surface plasmon resonance, chemiluminescence enzyme-linked immunosorbent assay, etc. However, the above detection methods currently have the disadvantages of long detection time, inconvenient portability of detection instruments, and high detection costs. Compared with other methods, fluorescence detection is fast, low-cost, and easy to carry. Some researchers have prepared it into a fluorescence sensing film for the detection of explosives: for example, some researchers deposited a blue fluorescence-emitting TCPC molecule and a green-emitting TCBzC molecule on ITO glass by electro-polymerization successively to prepare a dual-emission electro-polymerized film. However, the preparation process of the electro-polymerized film is complex, requires precise control of electro-polymerization conditions, and the stability and repeatability of the film may be affected by the environment; some researchers prepared a self-assembled oligodiphenylsilane film on a glass substrate, which can perform ultra-trace detection of TNT and DNT, but there is no relevant experimental data support for picric acid PA; there are also some researchers who designed and synthesized two fluoranthene derivatives TPFA and PO-TPFA with a "propeller" structure. However, the synthesis steps of the fluoranthene derivatives with a "propeller" structure are complex and the cost is high. Summary of the Invention

[0003] Aiming at the deficiencies of the prior art, the present invention provides a polydiphenylacetylene derivative capable of rapidly detecting nitrobenzene explosives, a synthesis method thereof, and an application thereof. The specific technical solutions are as follows:

[0004] A polydiphenylacetylene derivative capable of rapidly detecting nitrobenzene explosives has the following structural formula:

[0005]

[0006] Among them, the imidazole units in the three structural formulas are 1-alkylimidazole, 1-alkyl-3-methylimidazole, and 1-alkyl-2,3-dimethylimidazole respectively; the alkyl group is selected from any one of methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl, decyl, dodecyl, tetradecyl, hexadecyl, and octadecyl; the anion X is selected from any one of chloride ion, bromide ion, iodide ion, tetrafluoroborate ion, hexafluorophosphate ion, acetate ion, bis(trifluoromethanesulfonyl)imide ion, nitrate ion, perchlorate ion, hydrogen sulfate ion, dihydrogen phosphate ion, trifluoromethanesulfonate ion, trifluoroacetate ion, p-toluenesulfonate ion, alkyl group, amino group, hydroxyl group, alkoxy group, and trifluoromethanesulfonate group.

[0007] A preparation method of a polydiphenylacetylene derivative capable of rapidly detecting nitrobenzene explosives, comprising the following steps:

[0008] (1) Mix bis(triphenylphosphine)palladium dichloride, copper(I) iodide, and triphenylphosphine with a molar ratio of 1:2:2 as a catalyst, add trimethylsilylacetylene and 1-bromo-4-trimethylsilylbenzene with a volume ratio of 1:1, then add tetrahydrofuran and triethylamine, stir and heat at 60 - 80 °C for 6 - 12 h, and after post-treatment, obtain the product trimethyl(4-(trimethylsilyl)ethyl)phenyl)silane;

[0009] (2) Add the trimethyl(4-(trimethylsilyl)ethyl)phenyl)silane and potassium carbonate with a molar ratio of 1:4 to methanol, stir at room temperature for 2 - 6 h to completely dissolve and react, and after post-treatment, obtain the product (4-ethylphenyl)trimethylsilane;

[0010] (3) Add 4-iodophenylethanol, bis(triphenylphosphine)palladium dichloride, triphenylphosphine, and copper(I) iodide with a molar ratio of 360:1:4:5.5 to triethylamine and stir to obtain a mixed solution one; at the same time, add the (4-ethylphenyl)trimethylsilane to triethylamine and stir to dissolve to obtain a mixed solution two; mix the mixed solution one and the mixed solution two according to the molar ratio of the (4-ethylphenyl)trimethylsilane to the 4-iodophenylethanol of 1.2:1, mix and stir in an inert gas atmosphere at room temperature, and after cooling to room temperature, obtain 1-(p-trimethylsilyl)phenyl-2-(p-hydroxyethyl)phenylacetylene after post-treatment;

[0011] (4) Add the 1-(p-trimethylsilyl)phenyl-2-(p-hydroxyethyl)phenylacetylene, carbon tetrabromide, and triphenylphosphine with a molar ratio of 1:1.2:1.2 to anhydrous ether, stir and react at room temperature for 6 - 12 h, and after post-treatment, obtain a white needle-like polymer monomer;

[0012] (5) Polymerize the white needle-like polymer monomer obtained in step (4) to obtain a polydiphenylacetylene derivative precursor;

[0013] (6) React the poly(diphenylacetylene) derivative precursor obtained in step (5) with 1-alkylimidazole, 1-alkyl-3-methylimidazole, and 1-alkyl-2,3-dimethylimidazole respectively, attach the imidazole unit to the poly(diphenylacetylene) chain to obtain a product; then react the product with lithium bis(trifluoromethanesulfonyl)imide in a methanol solution, and perform post-treatment to obtain the poly(diphenylacetylene) derivative.

[0014] A fluorescence probe made of a poly(diphenylacetylene) derivative capable of rapidly detecting nitrobenzene explosives.

[0015] A method for preparing a fluorescence probe capable of rapidly detecting nitrobenzene explosives using a poly(diphenylacetylene) derivative, comprising the following steps:

[0016] S1: Clean the silicon wafer with a first organic solvent and deionized water to remove dust and particulate contaminants on the surface, and then perform vacuum drying;

[0017] S2: Dissolve the poly(diphenylacetylene) derivative in a second organic solvent, and obtain a poly(diphenylacetylene) derivative solution with a concentration of 2 - 8 mg / mL after ultrasonic treatment;

[0018] S3: After uniformly dropping the poly(diphenylacetylene) derivative solution obtained in step S2 onto the surface of the silicon wafer obtained in step S1, use a spin coater to rotate at a high speed to obtain a silicon wafer with a uniformly coated poly(diphenylacetylene) derivative on its surface;

[0019] S4: Put the silicon wafer coated with the poly(diphenylacetylene) derivative obtained in step S3 into an oven for drying to volatilize the organic solvent on the silicon wafer, and obtain the fluorescence probe.

[0020] Furthermore, the second organic solvent is selected from any one of acetone, acetonitrile, N,N-dimethylformamide, dimethyl sulfoxide, and methanol.

[0021] The detection principle of using the poly(diphenylacetylene) derivative as a fluorescence probe for the detection of nitrobenzene explosives is as follows: The recognition unit of the poly(diphenylacetylene) derivative is an imidazolium cation, which can form a strong electrostatic interaction with nitro explosive molecules. The signal sensing unit is a diphenylethylene group, which is connected by an alkyl chain, so that its diphenylethylene and imidazole groups and their ions are in the same plane, forming a π-π conjugated molecular wire structure, which can emit strong yellow-green fluorescence. The poly(diphenylacetylene) derivative has a strong electron-donating ability, can bind to electron-deficient nitro explosives, and both static quenching and dynamic quenching exist during the fluorescence detection process, so that nitro explosives can be detected quickly and sensitively.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] 1. The polydiphenylacetylene derivative of the present invention has become an important luminescent material due to its unique π-π conjugated molecular wire structure;

[0024] 2. The fluorescent probe containing the polydiphenylacetylene derivative prepared in the present invention has high fluorescence intensity and high detection sensitivity, and is an excellent fluorescent material for detecting nitrobenzene explosives;

[0025] 3. The detection speed of the present invention is fast. A portable explosives detector can display the fluorescence intensity in real time. According to the fluorescence decrease value, real-time monitoring of nitrobenzene explosives can be achieved. It can be used for the detection of nitrobenzene explosives in water environment systems and solid systems, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 FIG. is the Fourier transform infrared spectrum of the polydiphenylacetylene derivative.

[0027] Figure 2 FIG. is the fluorescence emission spectrum of the polydiphenylacetylene derivative in different organic solutions.

[0028] Figure 3 FIG. is the observation result diagram of the fluorescent probe prepared in Preparation Example 1 of the polydiphenylacetylene derivative fluorescent probe under a 20-fold microscope of an optical microscope.

[0029] Figure 4 FIG. is the fluorescence intensity change diagram when the sensing probe of the polydiphenylacetylene derivative detects picric acid in an explosives detector.

[0030] Figure 5 FIG. is the stability test diagram of the sensing probe of the polydiphenylacetylene derivative in an explosives detector. DETAILED DESCRIPTION OF THE INVENTION

[0031] The present invention will be described in detail below according to the drawings and preferred embodiments. The purpose and effect of the present invention will become more clear. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0032] Example 1

[0033] In this example, the reaction process for preparing the polydiphenylacetylene derivative is as follows:

[0034] (1) Put 21 mg of bis(triphenylphosphine)palladium dichloride, 11.4 mg of copper(I) iodide and 15.7 mg of triphenylphosphine (molar ratio 1:2:2) as catalysts into a double-tube, inject 3 mL of ultra-dry tetrahydrofuran and 3 mL of triethylamine using a syringe, then inject 0.5 mL of ethynyltrimethylsilane and 0.5 mL of 1-bromo-4-(trimethylsilyl)benzene, stir and heat at 70 °C under nitrogen protection for 12 h. After post-treatment, the product trimethyl(4-(trimethylsilyl)ethyl)phenyl)silane is obtained;

[0035] (2) Put 0.62 g of trimethyl(4-(trimethylsilyl)ethyl)phenyl)silane and 1.38 g of potassium carbonate (molar ratio 1:4) into a round-bottom flask, add 10 mL of methanol, stir at room temperature for 5 h. After post-treatment, the product (4-ethylphenyl)trimethylsilane is obtained;

[0036] (3) Add 12.4 g of 4-iodophenylethanol, 0.0964 g of bis(triphenylphosphine)palladium dichloride, 0.157 g of triphenylphosphine and 0.149 g of copper(I) iodide to a three-necked flask, then add 150 mL of triethylamine and stir to obtain a mixed solution I; at the same time, dissolve 11.2 g of (4-ethylphenyl)trimethylsilane in 50 mL of triethylamine by stirring to obtain a mixed solution II; then mix the mixed solution I and the mixed solution II, reflux and stir under nitrogen for 24 h, cool to room temperature, and after post-treatment operations such as extraction, column chromatography and recrystallization, 1-(p-trimethylsilyl)phenyl-2-(p-hydroxyethyl)phenylacetylene is obtained;

[0037] (4) React 4.4 g of 1-(p-trimethylsilyl)phenyl-2-(p-hydroxyethyl)phenylacetylene, 6.1 g of carbon tetrabromide and 4.7 g of triphenylphosphine (molar ratio 1:1.2:1.2) in 100 mL of anhydrous ether at room temperature for 12 h. After post-treatment, a white needle-like polymer monomer is obtained;

[0038] (5) Carry out a polymerization reaction on the white needle-like polymer monomer to obtain a polydiphenylacetylene derivative precursor;

[0039] (6) React the polydiphenylacetylene derivative precursor obtained in step (5) with 1-methylimidazole to attach the imidazole unit to the side chain of the polydiphenylacetylene, obtain the product, and then react it with lithium bis(trifluoromethanesulfonyl)imide in a methanol solution. After post-treatment, a polydiphenylacetylene derivative is obtained.

[0040] In order to explore the structural characteristics of the polydiphenylacetylene derivative and the influence of the solvent effect on its optical properties, the chemical structure of the polydiphenylacetylene derivative obtained in Example 1 was systematically characterized by Fourier transform infrared spectroscopy (FTIR), and the results are as Figure 1 shown. From Figure 1 it can be seen from the infrared spectrum that the synthesized polymer is a polydiphenylacetylene derivative.

[0041] Further, to clarify the regulatory effect of solvent polarity on the fluorescence properties of polydiphenylacetylene derivatives, acetone, acetonitrile (ACN), N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), and methanol were selected as the solvent system. The fluorescence intensity changes were analyzed by fluorescence spectroscopy, demonstrating that strong polar solvents have a significant regulatory mechanism on the luminescence properties of conjugated polymers. The results are as Figure 2 shown.

[0042] Example 2

[0043] (1) 42 mg of bis(triphenylphosphine)palladium dichloride, 22.8 mg of copper iodide, and 31.4 mg of triphenylphosphine were placed as catalysts into a double-ended tube. 6 mL of ultra-dry tetrahydrofuran and 6 mL of triethylamine were injected using a syringe. Then, 3 mL of ethynyltrimethylsilane and 3 mL of 1-bromo-4-(trimethylsilyl)benzene were injected. The mixture was stirred and heated at 70 °C under nitrogen protection for 8 h. After post-treatment, the product trimethyl(4-(trimethylsilyl)ethyl)phenyl)silane was obtained;

[0044] (2) 1.24 g of trimethyl(4-(trimethylsilyl)ethyl)phenyl)silane and 2.76 g of potassium carbonate were placed in a round-bottom flask, 10 mL of methanol was added, and the mixture was stirred at room temperature for 4 h. After post-treatment, the product (4-ethylphenyl)trimethylsilane was obtained

[0045] (3) 24.8 g of 4-iodophenylethanol, 0.1928 g of bis(triphenylphosphine)palladium dichloride, 0.314 g of triphenylphosphine, and 0.3 g of copper iodide were added to a three-necked flask. Then, 150 mL of triethylamine was added, and then 50 mL of triethylamine solution dissolving 22.4 g of (4-ethylphenyl)trimethylsilane was added. Nitrogen was passed through and the mixture was refluxed and stirred for 24 h. After cooling to room temperature, through post-treatment operations such as extraction, column chromatography, and recrystallization, 1-(p-trimethylsilyl)phenyl-2-(p-hydroxyethyl)phenylethyne was obtained;

[0046] (4) 8.8 g of 1-(p-trimethylsilyl)phenyl-2-(p-hydroxyethyl)phenylethyne, 12.2 g of carbon tetrabromide, and 9.4 g of triphenylphosphine were reacted at room temperature in 100 mL of anhydrous ether for 12 h. After post-treatment, a white needle-like polymer monomer was obtained;

[0047] (5) The white needle-like polymer monomer was subjected to a polymerization reaction to obtain a polydiphenylacetylene derivative precursor

[0048] (6) React the poly(diphenylacetylene) derivative precursor obtained in step (5) with 1-methylimidazole to attach the imidazole unit to the poly(diphenylacetylene) chain to obtain a product, and then react it with lithium bis(trifluoromethanesulfonyl)imide in a methanol solution, and perform post-treatment to obtain the poly(diphenylacetylene) derivative.

[0049] Example 3

[0050] The reaction process for preparing the poly(diphenylacetylene) derivative in this example is as follows:

[0051] (1) Put 21 mg of bis(triphenylphosphine)palladium dichloride, 11.4 mg of copper(I) iodide, and 15.7 mg of triphenylphosphine as catalysts into a double-necked tube. Use a syringe to inject 3 mL of ultra-dry tetrahydrofuran and 3 mL of triethylamine, and then inject 0.5 mL of ethynyltrimethylsilane and 0.5 mL of 1-bromo-4-(trimethylsilyl)benzene. Stir and heat at 70 °C under nitrogen protection for 12 h. After post-treatment, the product trimethyl(4-(trimethylsilyl)ethyl)phenyl)silane is obtained.

[0052] (2) Put 0.62 g of trimethyl(4-(trimethylsilyl)ethyl)phenyl)silane and 1.38 g of potassium carbonate into a round-bottom flask, add 10 mL of methanol, and stir at room temperature for 5 h. After post-treatment, the product (4-ethylphenyl)trimethylsilane is obtained.

[0053] (3) Add 12.4 g of 4-iodophenethyl alcohol, 0.0964 g of bis(triphenylphosphine)palladium dichloride, 0.157 g of triphenylphosphine, and 0.149 g of copper(I) iodide to a three-necked flask. Then add 150 mL of triethylamine, and then add it to 50 mL of triethylamine in which 11.2 g of (4-ethylphenyl)trimethylsilane is dissolved. Pass nitrogen and reflux and stir for 24 h. Cool to room temperature. After post-treatment operations such as extraction, column chromatography, and recrystallization, 1-(p-trimethylsilyl)phenyl-2-(p-hydroxyethyl)phenylacetylene is obtained.

[0054] (4) React 4.4 g of 1-(p-trimethylsilyl)phenyl-2-(p-hydroxyethyl)phenylacetylene, 6.1 g of carbon tetrabromide, and 4.7 g of triphenylphosphine in 100 mL of anhydrous ether at room temperature for 12 h. After post-treatment, a white needle-like polymer monomer is obtained.

[0055] (5) Perform a polymerization reaction on the white needle-like polymer monomer to obtain a poly(diphenylacetylene) derivative precursor.

[0056] (6) React the bromoethyl group in the poly(diphenylacetylene) derivative precursor obtained in step (5) with 1-methyl-3-methylimidazole to attach the imidazole unit to the poly(diphenylacetylene) chain to obtain a product, and then react it with lithium bis(trifluoromethanesulfonyl)imide in a methanol solution, and perform post-treatment to obtain the poly(diphenylacetylene) derivative.

[0057] Example 4

[0058] In this embodiment, the reaction process for preparing the polydiphenylacetylene derivative is as follows:

[0059] (1) Put 21 mg of bis(triphenylphosphine)palladium dichloride, 11.4 mg of copper(I) iodide, and 15.7 mg of triphenylphosphine as catalysts into a double-tube, inject 3 mL of ultra-dry tetrahydrofuran and 3 mL of triethylamine using a syringe, then inject 0.5 mL of ethynyltrimethylsilane and 0.5 mL of 1-bromo-4-(trimethylsilyl)benzene, stir and heat at 70 °C under nitrogen protection for 12 h, and obtain the product trimethyl(4-(trimethylsilyl)ethyl)phenyl)silane after post-treatment;

[0060] (2) Put 0.62 g of trimethyl(4-(trimethylsilyl)ethyl)phenyl)silane and 1.38 g of potassium carbonate into a round-bottom flask, add 10 mL of methanol, stir at room temperature for 5 h, and obtain the product (4-ethylphenyl)trimethylsilane after post-treatment

[0061] (3) Add 12.4 g of 4-iodophenylethanol, 0.0964 g of bis(triphenylphosphine)palladium dichloride, 0.157 g of triphenylphosphine, and 0.149 g of copper(I) iodide to a three-necked flask, then add 150 mL of triethylamine, and then add it to 50 mL of triethylamine dissolving 11.2 g of (4-ethylphenyl)trimethylsilane, reflux and stir under nitrogen for 24 h, cool to room temperature, and obtain 1-(p-trimethylsilyl)phenyl-2-(p-hydroxyethyl)phenylacetylene after post-treatment operations such as extraction, column chromatography, and recrystallization;

[0062] (4) React 4.4 g of 1-(p-trimethylsilyl)phenyl-2-(p-hydroxyethyl)phenylacetylene, 6.1 g of carbon tetrabromide, and 4.7 g of triphenylphosphine in 100 mL of anhydrous ether at room temperature for 12 h, and obtain a white needle-like polydiphenylacetylene derivative precursor after post-treatment;

[0063] (5) Polymerize the white needle-like polymer monomer to obtain a polydiphenylacetylene derivative precursor;

[0064] (6) React the bromoethyl groups in the polydiphenylacetylene derivative precursor obtained in step (5) with 1-methyl-2,3-dimethylimidazole respectively to attach the imidazole units to the polydiphenylacetylene chain to obtain a product, and then react it with sodium trifluoromethanesulfonate in a methanol solution, and obtain the polydiphenylacetylene derivative after post-treatment.

[0065] Example 5

[0066] The steps for obtaining a fluorescent probe from the polydiphenylacetylene derivative prepared above and using it to detect nitrobenzene explosives are as follows:

[0067] (1) Clean the silicon wafer with organic solvents and deionized water to remove dust and particulate contaminants on the surface, and dry it in a vacuum drying oven for later use.

[0068] (2) Dissolve the polydiphenylacetylene derivative obtained in Example 1 in methanol, and ultrasonically dissolve it at room temperature to prepare a polydiphenylacetylene derivative solution with a concentration of 8 mg / mL.

[0069] (3) After uniformly dropping the polydiphenylacetylene derivative solution obtained in step (2) onto the surface of the cleaned silicon wafer obtained in step (1), use a spin coater to rotate it at 1000 r / min for 40 s to obtain a silicon wafer with a uniformly coated polydiphenylacetylene derivative on its surface.

[0070] (4) Put the silicon wafer coated with the polydiphenylacetylene derivative obtained in step (3) into a vacuum drying oven at 80 °C and dry it for 24 h to volatilize the organic solvent on the silicon wafer, obtaining a fluorescent probe of the polydiphenylacetylene derivative. The observation result diagram of the fluorescent probe obtained in this example under a 20-fold optical microscope is as Figure 3 shown. It can be seen from Figure 3 that the polydiphenylacetylene material coating adheres to the silicon wafer with a good porosity to reduce π-π stacking, which is beneficial for the detection of explosive gases.

[0071] (5) Use the silicon wafer containing the polydiphenylacetylene derivative dried in step (4) as a fluorescent probe, put it into an explosive detector, and the fluorescence intensity of the detection system changes with the concentration change of nitrobenzene explosives. Judge the presence of nitrobenzene explosives according to the magnitude of the fluorescence quenching value.

[0072] The usage method of the explosive detector is as follows: (1) Dip a sampling paper into the nitrobenzene explosive or drop the solution containing the nitrobenzene explosive on the sampling paper and wait for the solution to volatilize completely; (2) Insert the sampling paper containing the nitrobenzene explosive into the explosive detector; (3) Judge whether there is an explosive according to the fluorescence intensity displayed by the explosive detector.

[0073] Furthermore, according to the change of the fluorescence intensity in the explosive detector with the change of the explosive concentration, the detection sensitivity can be calculated and the detection limit can be determined.

[0074] Examples 6 - 9

[0075] The steps are the same as those in Example 5, except that the second organic solvents in which the polydiphenylacetylene derivative obtained in Example 1 is dissolved in step (2) are different. The second organic solvents in Examples 6 - 9 are dimethyl sulfoxide, N,N-dimethylformamide, acetonitrile, and acetone respectively.

[0076] Use the detection method for detecting nitrobenzene explosives with the fluorescent probe obtained in Example 5 to detect the explosive picric acid:

[0077] After drying, the silicon wafer containing polydiphenylacetylene derivatives is cut into small silicon wafers of 4mm * 4mm as fluorescence sensing probes and placed into the explosive detector. Reducing the size of the fluorescence sensing probes is more conducive to saving the detection cost and expanding the application range of the product. Then, use a sampling paper to dip in nitrobenzene explosives or drop the solution containing nitrobenzene explosives on the sampling paper. After the solution has completely volatilized, insert it into the explosive detection instrument, and judge whether there is an explosive according to the fluorescence intensity displayed by the explosive detector. As Figure 4 shown, it is the real-time fluorescence intensity change of detecting picric acid by putting the fluorescence sensing probe containing polydiphenylacetylene derivatives into the explosive detector: among them, region a and region c represent the fluorescence intensity self-decay curve of the fluorescence polymer sensing probe over time, and region c also represents the fluorescence change after the sensor detects the explosive, and the fluorescence intensity has a significant increase compared to the lowest point when the explosive is detected; region b represents the fluorescence intensity change when the fluorescence polymer sensing probe reacts with 1500 ng / μL picric acid; region d represents the fluorescence intensity change when the fluorescence polymer sensing probe reacts with 3000 ng / μL picric acid; points 1 and 2 are the moments when the sensing probe containing polydiphenylacetylene derivatives detects the explosive. Due to the fluorescence quenching reaction between the explosive and polydiphenylacetylene derivatives, the fluorescence intensity drops rapidly. From the fluorescence intensity change in the figure, it can be concluded that the fluorescence polymer sensing probe prepared with polydiphenylacetylene derivatives can well detect nitrobenzene explosives.

[0078] To further ensure the stability of the fluorescence sensing material, we conduct a blank measurement of the fluorescence probe prepared by the preparation method of the probe for detecting nitrobenzene explosives in Example 5 without inserting the sampling paper containing explosives. As Figure 5 shown: Region a and c represent the fluorescence change curves of the fluorescence polymer sensing probe under the condition of blank measurement without adding explosives, and region b represents the fluorescence intensity self-decay curve of the fluorescence polymer sensing probe over time. The stability test mainly compares whether the fluorescence intensity decreased each time in region a and region c under the blank measurement condition is the same after the fluorescence self-decay through region b. After comparing the fluorescence intensity decrease values of region a and region c in Figure 5 , it meets the requirement that the fluorescence decrease values are the same. From this, it can be obtained that the fluorescence sensing probe containing polydiphenylacetylene derivatives prepared by us has good stability and meets the experimental requirements.

[0079] Those of ordinary skill in the art can understand that the above are only preferred examples of the invention and are not used to limit the invention. Although the invention has been described in detail with reference to the foregoing examples, for those skilled in the art, they can still modify the technical solutions recorded in the foregoing examples, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, etc. made within the spirit and principle of the invention shall be included within the protection scope of the invention.

Claims

1. A polyphenylene acetylene derivative capable of rapidly detecting nitrobenzene explosives, characterized in that: The structural formula is as follows: The imidazole units in the three structural formulas are 1-alkylimidazole, 1-alkyl 3-methylimidazole and 1-alkyl-2,3-dimethylimidazole respectively; the alkyl group is selected from any one of methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl, decyl, dodecyl, tetradecyl, hexadecyl and octadecyl; the anion X is selected from any one of chloride, bromide, iodide, tetrafluoroborate, hexafluorophosphate, acetate, bistrifluoromethanesulfonyl imide, nitrate, perchlorate, hydrogen sulfate, dihydrogen phosphate, trifluoromethanesulfonate, trifluoroacetate, p-toluenesulfonate, alkyl, amino, hydroxyl, alkoxy and trifluoromethanesulfonate.

2. A method for preparing a polyphenylene derivative capable of rapidly detecting nitrobenzene explosives as claimed in claim 1, characterized in that: The steps include: (1) Bistriphenylphosphine palladium dichloride, cuprous iodide and triphenylphosphine in a molar ratio of 1:2:2 are mixed as a catalyst, trimethylsilyl acetylene and 1-bromo-4-trimethylsilylbenzene in a volume ratio of 1:1 are added, and then tetrahydrofuran and triethylamine are added, and the mixture is stirred and heated at 60-80° C. for 6-12 hours, and the product trimethyl(4-(trimethylsilyl)ethyl)phenyl)silane is obtained after post-treatment; (2) adding the trimethyl(4-(trimethylsilyl)ethyl)phenyl)silane and potassium carbonate in a molar ratio of 1:4 to methanol, stirring at room temperature for 2-6 hours to completely dissolve and react, and obtaining the product (4-ethylphenyl)trimethylsilane after post-treatment; (3) adding 4-iodophenethyl alcohol, bistriphenylphosphine palladium dichloride, triphenylphosphine and cuprous iodide in a molar ratio of 360:1:4:5.5 to triethylamine and stirring to obtain a mixed solution 1; at the same time, adding the (4-ethylphenyl)trimethylsilane to triethylamine and stirring to dissolve to obtain a mixed solution 2; mixing the mixed solution 1 and the mixed solution 2 in an inert gas atmosphere at room temperature according to a molar ratio of the (4-ethylphenyl)trimethylsilane to the 4-iodophenethyl alcohol of 1.2:1, and cooling to room temperature, and post-treating to obtain 1-(p-trimethylsilyl)phenyl-2-(p-hydroxyethyl)phenylacetylene; (4) adding the 1-(p-trimethylsilyl)phenyl-2-(p-hydroxyethyl)phenylacetylene, carbon tetrabromide and triphenylphosphine in a molar ratio of 1:1.2:1.2 to anhydrous ether, stirring at room temperature for 6-12 hours, and obtaining a white needle-shaped polymer monomer after post-treatment; (5) subjecting the white needle-shaped polymer monomer obtained in step (4) to polymerization to obtain a poly(phenylene vinylene) derivative precursor; (6) reacting the poly(diphenylvinylene) derivative precursor obtained in step (5) with 1-alkylimidazole, 1-alkyl 3-methylimidazole, and 1-alkyl-2,3-dimethylimidazole, respectively, attaching the imidazole unit to the poly(diphenylvinylene) chain to obtain a product; and then reacting the product with lithium bis(trifluoromethylsulfonyl)imide in a methanol solution, and post-treating to obtain a poly(diphenylvinylene) derivative.

3. A fluorescent probe made of the polyphenylene acetylene derivative capable of rapidly detecting nitrobenzene explosives as claimed in claim 1.

4. A method for preparing a fluorescent probe capable of rapidly detecting nitrobenzene explosives using the polyphenylene acetylene derivative according to claim 1, characterized in that: The steps include: S1: Cleaning the silicon wafer with a first organic solvent and deionized water to remove dust and particulate contaminants on the surface, and then vacuum drying; S2: dissolving the poly(diphenylvinylene) derivative in a second organic solvent, and obtaining a 2-8 mg / mL poly(diphenylvinylene) derivative solution after ultrasonication; S3: evenly drop-coating the poly(diphenylvinylene) derivative solution obtained in step S2 on the surface of the silicon wafer obtained in step S1, and then using a spin coater to spin at high speed to obtain a silicon wafer evenly coated with the poly(diphenylvinylene) derivative; S4: Put the silicon wafer coated with the polydiphenylvinylene derivative obtained in step S3 into an oven for drying, so that the organic solvent on the silicon wafer evaporates, thereby obtaining a fluorescent probe.

5. The method according to claim 4, characterized in that The second organic solvent is selected from any one of acetone, acetonitrile, N,N-dimethylformamide, dimethyl sulfoxide, and methanol.

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