A Cyano-Distyryl Crown Ether Macrocycle Fluorescent Probe and Its Synthesis Method and Application

Abstract

The present invention discloses a cyano-distyryl crown ether macrocyclic fluorescent probe, its synthesis method and application, belonging to the technical fields of organic synthesis and analytical chemistry. The cyano-distyryl crown ether macrocyclic fluorescent probe has a "2 + 2" macrocyclic structure with cyano-distyryl as the structural unit bridged by a crown ether chain, and its chemical name is tetra-(4-triethyleneglycolyl-1-cyano-1,2-diphenylvinyl) macrocycle; in a pure tetrahydrofuran solution, this fluorescent probe has a very weak light blue fluorescence emission at 446 nm, but in a tetrahydrofuran-water (5:95) solution, this probe has an obvious visible blue-green fluorescence emission at 446 nm. When this fluorescent probe is formulated into a certain concentration of tetrahydrofuran-water solution and mixed with the carbendazim solution to be detected, this fluorescent probe has a strong intermolecular interaction with carbendazim, and its fluorescence intensity is significantly enhanced, and the presence of other guests has little interference on its detection effect, and the efficient and selective detection of the pesticide carbendazim can be realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of organic synthesis and analytical chemistry, and particularly relates to a cyano-distyryl crown ether macrocyclic fluorescent probe, a synthesis method thereof and an application thereof. Background Art

[0002] Carbendazim is a benzimidazole drug and is also the main metabolite of benomyl in mammals and the degradation product in the environment. As a broad-spectrum and highly effective fungicide, carbendazim is widely used to control powdery mildew, downy mildew and other diseases of various agricultural products such as vegetables and fruits, and can effectively control plant diseases caused by fungi such as wheat, rice and cotton, and prevent wound rot during the cutting of succulent plants. However, it is toxic to humans and animals, and can cause poisoning symptoms such as excitement, convulsions, mental trance, nausea and vomiting, dizziness, headache, chest tightness, upper abdominal tenderness, etc. through the esophagus. Long-term intake will accumulate in the body and cause liver diseases and chromosome aberrations, thus leading to chronic or acute toxicity and affecting human health.

[0003] At present, the existing detection methods for carbendazim mostly rely on gas chromatography, liquid chromatography and their combination with mass spectrometry technology. The detection cycle is long, the procedure is complex, the required instrument cost is expensive, and the requirements for operators are high, which limits its use only in professional laboratories and makes it difficult to conduct large-scale sample screening and monitoring of the agricultural product food production process in a timely, convenient and economical manner. Therefore, seeking a rapid, convenient, accurate and economically feasible detection method has become an urgent problem to be solved in the research on carbendazim residue analysis.

[0004] In recent years, the fluorescent probe technology has been widely used in the fields of medicine, food, hygiene, etc. In the method for detecting substances, the target to be detected can be realized by using the property of the fluorescent probe having specific fluorescence, and the fluorescent probe can also react with the target to be detected to generate a highly specific chemical reaction and produce a highly sensitive fluorescent signal for qualitative and quantitative detection of trace or ultra-trace targets to be detected. However, many conventional fluorescent materials can emit light well in solution, but once they aggregate or become solid, the fluorescence phenomenon will be severely weakened, which hinders the application of these fluorescent materials in poor solvents such as water environment.

[0005] Cyanostilbene and its derivative molecules have low luminescence efficiency in dilute solutions, but have strong luminescence efficiency in concentrated solutions or in the aggregated state. This property lays a good foundation for their luminescence applications in the aqueous phase. The synthesis of a series of cyanostilbene-based fluorescent probes and their detection of specific guest ions or molecules in the aqueous phase have been reported. In addition, the research on macrocyclic compounds with unique guest inclusion ability is one of the research hotspots in recent years and has received much attention in host-guest chemistry. The construction of novel macrocyclic molecules with unique structures and specific recognition functions is in the ascendant. Therefore, constructing a fluorescent probe molecule based on cyanostilbene for the efficient and rapid detection of carbendazim has strong practical significance and good application value in agriculture and other aspects.

[0006] The invention with the publication number CN103472122A discloses an electrochemical sensor detection method for detecting trace carbendazim pesticides. The sensor is placed in a carbendazim solution, B-R buffer solution is added, and differential pulse voltammetry is used for detection. Although this method can detect trace carbendazim pesticides, it is relatively complex, has a long cycle, and is time-consuming and laborious, so it has certain limitations in application.

[0007] Jiang Xintian and Ding Ming studied the fluorescence method for the determination of carbendazim in 1989. Their research is based on the property that carbendazim has strong fluorescence emission in acidic media but no fluorescence in alkaline media. However, in this study, the fluorescence of carbendazim is easily affected by factors such as acidity, temperature, and reagents, and is unstable, resulting in low accuracy of the quantitative determination results of carbendazim, and it is only suitable for the detection of carbendazim under acidic conditions and not suitable for alkaline conditions.

[0008] The invention with the publication number CN103175813A discloses a method for simultaneously and rapidly determining the contents of carbendazim and thiabendazole in vegetables by fluorescence spectroscopy. This invention pre-treats the sample through simple extraction steps, then collects the three-dimensional excitation-emission fluorescence spectrum of the sample, and processes the obtained spectral data to obtain a three-dimensional data matrix; then a calibration model is made, and then the three-dimensional excitation-emission matrix fluorescence spectra of each sample are collected and processed under the same experimental parameters. The resolved relative concentrations are input into the calibration model, and the concentrations of carbendazim and thiabendazole in each sample are obtained through the prediction of the calibration model. Although this method can achieve the simultaneous quantitative detection of two target pesticides in vegetables, the process of establishing the model and collecting the three-dimensional excitation-emission matrix fluorescence spectra of each sample is still relatively complex. Summary of the Invention

[0009] To solve the problems existing in the prior art, the purpose of the present invention is to provide a cyanostilbene crown ether macrocyclic fluorescent probe, its synthesis method and application. The fluorescence intensity is significantly enhanced in the presence of carbendazim, and the presence of other ions has little interference on the detection result of this fluorescent probe. By using the increase in the fluorescence intensity of the fluorescent probe, the efficient and selective detection of carbendazim can be achieved.

[0010] The technical solution of the present invention is as follows:

[0011] One of the purposes of the present invention is to provide a cyanostilbene crown ether macrocyclic fluorescent probe. The chemical name of the fluorescent probe is tetra-(4-triethyleneglycolyl-1-cyano-1,2-diphenylvinyl) macrocycle, which has a macrocyclic structure with cyanostilbene as the structural unit bridged by a crown ether chain. The chemical structural formula is shown in (I):

[0012] Its molecular formula is C 84 H 84 N4O 16 .

[0013] Furthermore, the infrared spectrum characterization of the fluorescent probe is as follows: (KBr), v / cm -1 : 3327, (CH2), 3059 (CH), 1597 (CN);

[0014] The nuclear magnetic resonance hydrogen spectrum characterization is as follows: 1 H NMR (400 MHz, CDCl3) δ ppm : 7.30 (d, J = 8.0 Hz, 8H, ArH), 7.21 (s, 4H, CH=CCN), 7.11 (d, J = 8.0 Hz, 8H, ArH), 6.89 (d, J = 8.0 Hz, 8H, ArH), 6.76 (d, J = 8.0 Hz, 8H, ArH), 4.17 (t, J = 4.0 Hz, 8H, OCH2), 4.10 (t, J = 4.0 Hz, 8H, OCH2), 3.92 ((t, J = 4.0 Hz, 8H, OCH2), 3.86 ((t, J = 4.0 Hz, 8H, OCH2), 3.81 (s, 8H, OCH2), 3.75 (s, 8H, OCH2);

[0015] The nuclear magnetic resonance carbon spectrum characterization is as follows: 13 C NMR (100 MHz, CDCl3) δ ppm: 159.86, 159.29, 142.92, 131.47, 130.81, 130.29, 126.60, 125.36, 114.99, 114.51, 111.51, 77.03, 69.64, 67.52;

[0016] High-resolution mass spectrometry (m / s): Calculated value (C 84 H 84 N4O 16 ): 1404.588; Measured value: 1404.583 [MH] + and 1427.585 [M+Na + ;

[0017] Elemental analysis: Calculated value (C 84 H 84 N4O 16 ): C, 71.78; H, 6.02; N, 3.99; Measured value: C, 71.74; H, 6.04; N, 4.01.

[0018] The second object of the present invention is to provide a preparation method of a cyanodiphenylstilbene crown ether macrocyclic fluorescent probe, comprising the following steps:

[0019] (1) Under ice bath conditions, stir triethylene glycol and p-toluenesulfonyl chloride in anhydrous pyridine to precipitate a white solid. Then, slowly pour the entire reaction mixture into hydrochloric acid with stirring, add dichloromethane solution to extract the organic matter, separate the organic layer and concentrate it, add methanol to precipitate, obtain a white solid, and filter and dry it to obtain triethylene glycol bis(p-toluenesulfonate), that is, compound 1. The synthesis process is as follows:

[0020]

[0021] (2) Add compound 1, p-hydroxybenzyl cyanide, anhydrous potassium carbonate, and potassium iodide to anhydrous acetonitrile for reflux. After evaporating most of the solvent, add dichloromethane and hydrochloric acid solution, stir well and separate the layers. After separating the organic layer, dry it, concentrate it, add methanol, and place it in the refrigerator overnight to fully precipitate the solid. Filter out the solid and dry it to obtain compound 2. The synthesis process is as follows:

[0022]

[0023] (3) Add compound 1, p-hydroxybenzaldehyde, anhydrous potassium carbonate, and potassium iodide to anhydrous acetonitrile, reflux and then evaporate most of the solvent. Add dichloromethane and hydrochloric acid solution, stir well and separate the layers. After separating the organic layer, dry it, concentrate it, add methanol, and place it in the refrigerator overnight to fully precipitate the solid. Filter out the solid and dry it to obtain compound 3. The synthesis process is as follows:

[0024]

[0025] (4) Under the protection of a nitrogen atmosphere, in a flask, compound 2, compound 3 and sodium hydroxide are added to anhydrous ethanol and stirred under reflux. After the reaction is completed, a solid precipitates.

[0026] (5) Filter out the solid obtained in step (3), dissolve it with chloroform, wash it with distilled water to separate the organic layer, concentrate the organic layer and subject it to silica gel column chromatography to obtain a yellow-green solid, namely the cyanostilbene crown ether macrocycle fluorescent probe.

[0027] Furthermore, the synthesis methods of compound 2 and compound 3 refer to the published literature (Wu, Y.; Zheng, S.; Guo, H.; Yang, F. Crown-ether-bridging bis-diphenylacrylonitrile macrocycle: The effect fluorescence sensor for oxytetracycline, Photochem. Photobiol., A, 2021, 412, 113219).

[0028] Furthermore, in step (1), the molar ratio of triethylene glycol to p-toluenesulfonyl chloride is 1:2; the mass fraction of hydrochloric acid is 10%.

[0029] Furthermore, in step (2), the molar ratio of compound 1, p-hydroxybenzyl cyanide, anhydrous potassium carbonate and potassium iodide is 2:4:8:1, and the molar concentration of hydrochloric acid is 1 mol / L.

[0030] Furthermore, in step (3), the molar ratio of compound 1, p-hydroxybenzaldehyde, anhydrous potassium carbonate and potassium iodide is 2:4:8:1, and the molar concentration of hydrochloric acid is 1 mol / L.

[0031] Furthermore, in step (4), the molar ratio of compound 2, compound 3 and sodium hydroxide is 1:0.5 - 1.5:0.5 - 1.5.

[0032] Furthermore, in step (4), the stirring and refluxing time is 12 - 36 h.

[0033] Furthermore, in step (5), the eluent for silica gel column chromatography separation is a mixed solution of ethyl acetate and petroleum ether.

[0034] Furthermore, the volume ratio of ethyl acetate to petroleum ether in the mixed solution is 1:3.

[0035] The third object of the present invention is to provide an application of a cyano-diphenyl ethylene crown ether macrocycle fluorescent probe. By adding a tetrahydrofuran-water mixed solution containing the cyano-diphenyl ethylene crown ether macrocycle fluorescent probe to a sample solution to be measured, and comparing with a standard working curve of the fluorescence intensity varying with the carbendazim concentration, the rapid and efficient detection of the carbendazim content in the sample solution can be achieved.

[0036] Further, the fluorescent probe of the present invention is formulated into a solution of tetrahydrofuran-water at a certain concentration. At the same time, a series of carbendazim solutions with gradient-changing concentrations are prepared according to 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 2.0, 3.0, 4.0 times the concentration of the fluorescent probe. The fluorescent probe is respectively mixed with this series of carbendazim solutions, and then the fluorescence intensity of the mixed solution is measured to establish a standard working curve of the fluorescence intensity varying with the carbendazim concentration gradient with the fluorescence intensity as the ordinate and the carbendazim concentration as the abscissa.

[0037] Further, the fluorescent probe is mixed with the carbendazim solution to be measured, and the fluorescence intensity value after mixing is measured. The obtained fluorescence intensity value is compared with the standard working curve of the carbendazim concentration gradient change established above, and the carbendazim gradient in the solution to be measured is read from the curve graph.

[0038] Further, the volume ratio of tetrahydrofuran to water in the mixed solution is 5:95.

[0039] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0040] 1. The present invention designs a cyano-diphenyl ethylene crown ether macrocycle fluorescent probe, which has a "2+2" macrocycle structure with cyano-diphenyl ethylene as the structural unit bridged by a crown ether chain, and is an ideal sensor for rapid and sensitive detection of carbendazim. When this fluorescent probe is placed in a pure tetrahydrofuran solution, there is a very weak light blue fluorescence emission at 446 nm, but in a tetrahydrofuran-water (5:95) mixed solution, there is an obvious visible blue-green fluorescence emission at this wavelength. When a carbendazim sample to be measured is added to the mixed solution containing the fluorescent probe, there is a strong intermolecular interaction between the fluorescent probe and carbendazim, and this intermolecular interaction causes the fluorescence intensity of the fluorescent probe to increase significantly, thus realizing the selective and sensitive detection of carbendazim.

[0041] 2. The cyano-diphenyl ethylene crown ether macrocycle fluorescent probe disclosed by the present invention has strong anti-interference ability, can selectively detect carbendazim alone, and the detection limit can reach 7.8×10 -6 M, and the presence of other guests has little or negligible interference on the detection of carbendazim. It is suitable for the detection of carbendazim in various agricultural crops and environmental water samples, has a wide application prospect, and has the advantages of simple detection method and common detection instruments.

[0042] 3. Compared with the existing fluorescence probe technologies, the cyanostilbene crown ether macrocyclic fluorescence probe constructed in the present invention has strong luminescence efficiency in concentrated solutions or in an aggregated state, and the synthesis method is simple and energy-saving. It can be generated by mixing at normal temperature and pressure without high-energy excitation, is environmentally friendly, and can be widely applied in the fields of life science, environmental science, etc. It has important reference value in the field of constructing novel macrocyclic molecules with unique structures and specific recognition functions.

[0043] Reference numerals

[0044] Figure 1 is the process flow chart of the preparation method of the cyanostilbene crown ether macrocyclic fluorescence probe described in the present invention;

[0045] Figure 2 is the standard working curve of the concentration gradient change of carbendazim and the fluorescence intensity change in Example 4 of the present invention;

[0046] Figure 3 is the fluorescence emission spectrum of the cyanostilbene crown ether macrocyclic fluorescence probe described in the present invention reacting with various pesticide molecules in a tetrahydrofuran-water mixed solution;

[0047] Figure 4 is the fluorescence emission spectrum of the cyanostilbene crown ether macrocyclic fluorescence probe described in the present invention reacting with different concentrations of carbendazim in a tetrahydrofuran-water mixed solution;

[0048] Figure 5 is the comparison chart of the ratio of the fluorescence intensity of the cyanostilbene crown ether macrocyclic fluorescence probe described in the present invention reacting with other guests (or other guests + carbendazim) to its own fluorescence intensity in a tetrahydrofuran-water mixed solution. The other guests are, in order, 1 = blank, 2 = imidacloprid, 3 = hymexazol, 4 = carbendazim, 5 = glyphosate, 6 = thiophanate-methyl, 7 = pyrimidinylsulfuron, 8 = naphthaleneacetic acid, 9 = mancozeb, 10 = dimehypo, 11 = tricyclazole, 12 = picloram, 13 = monosultap, 14 = dichlorvos, 15 = paclobutrazol, 16 = glufosinate-ammonium, 17 = hexazinone, 18 = thiamethoxam;

[0049] Figure 6 is the infrared spectrum diagram of the cyanostilbene crown ether macrocyclic fluorescence probe described in the present invention;

[0050] Figure 7 is the nuclear magnetic resonance hydrogen spectrum diagram of the cyanostilbene crown ether macrocyclic fluorescence probe described in the present invention;

[0051] Figure 8 is the nuclear magnetic resonance carbon spectrum diagram of the cyanostilbene crown ether macrocyclic fluorescence probe described in the present invention;

[0052] Figure 9This is the mass spectrum of the cyanostilbene crown ether macrocyclic fluorescent probe of the present invention. Specific Embodiments

[0053] The present invention will be further described below in conjunction with the accompanying drawings and preferred embodiments. The provided embodiments are only for clarifying the present invention, rather than limiting the scope of the present invention.

[0054] The materials, reagents, etc. used in the following embodiments can be obtained from commercial channels without special instructions;

[0055] In the following quantitative tests, three repeated experiments are set, and the results are averaged;

[0056] The experimental methods in the following embodiments are all conventional methods without special instructions.

[0057] Example 1

[0058] This example provides a cyanostilbene crown ether macrocyclic fluorescent probe, and its synthesis method is as Figure 1 shown, including the following steps:

[0059] (1) Under ice bath conditions, 0.1 mol of triethylene glycol and 0.2 mol of p-toluenesulfonyl chloride are added to 100 mL of anhydrous pyridine, and stirred for 8 h. A large amount of white precipitate precipitates. After stirring, the reaction mixture is slowly poured into 200 mL of 10% hydrochloric acid, and then 100 mL of dichloromethane solution is added to extract the organic matter. The organic layer is separated, concentrated, methanol is added for precipitation, a white solid is obtained, filtered and dried to obtain triethylene glycol bis(p-toluenesulfonate), that is, Compound 1;

[0060] (2) 2 mmol of Compound 1, 4 mmol of p-hydroxybenzyl cyanide, 8 mmol of anhydrous potassium carbonate and 1 mmol of potassium iodide are added to 50 mL of anhydrous acetonitrile. After refluxing for 24 hours, most of the solvent is evaporated. 50 mL of dichloromethane and 50 mL of 1 M hydrochloric acid solution are added, stirred well and layered. The organic layer is separated, dried, concentrated, 50 mL of methanol is added, and the mixture is placed in the refrigerator overnight to fully precipitate the solid. The solid is filtered out and dried to obtain Compound 2;

[0061] (3) 2 mmol of Compound 1, 4 mmol of p-hydroxybenzaldehyde, 8 mmol of anhydrous potassium carbonate and 1 mmol of potassium iodide are added to 50 mL of anhydrous acetonitrile. After refluxing for 24 hours, most of the solvent is evaporated. 50 mL of dichloromethane and 50 mL of 1 M hydrochloric acid solution are added, stirred well and layered. The organic layer is separated, dried, concentrated, 50 mL of methanol is added, and the mixture is placed in the refrigerator overnight to fully precipitate the solid. The solid is filtered out and dried to obtain Compound 3;

[0062] (4) In a flask, 1 mmol of compound 2, 0.5 mmol of compound 3 and 0.5 mmol of sodium hydroxide were added to 100 mL of 99.5% absolute ethanol, and the mixture was stirred and refluxed for 36 h. After the reaction was completed, a solid was precipitated.

[0063] (5) The solid obtained in step (4) was filtered out, dissolved in 40 mL of chloroform, washed twice with 30 mL of distilled water, and the organic layer was separated. The organic layer was concentrated and subjected to silica gel column chromatography (eluent: ethyl acetate / petroleum ether = 1:3, V / V) to obtain a yellow-green solid, namely the cyanostilbene crown ether macrocyclic fluorescent probe (molecular formula: C 84 H 84 N4O 16 ), and the yield was 32%.

[0064] Example 2

[0065] This example provides a method for synthesizing a cyanostilbene crown ether macrocyclic fluorescent probe, as Figure 1 shown, which includes the following steps:

[0066] (1) Under ice bath conditions, 0.1 mol of triethylene glycol and 0.2 mol of p-toluenesulfonyl chloride were added to 100 mL of anhydrous pyridine, and the mixture was stirred for 8 h. A large amount of white precipitate was formed. After stirring, the reaction mixture was slowly poured into 200 mL of 10% hydrochloric acid, and then 100 mL of dichloromethane solution was added to extract the organic matter. The organic layer was separated, concentrated, methanol was added for precipitation, and a white solid was obtained. After filtration and drying, triethylene glycol bis(p-toluenesulfonate), namely compound 1, was prepared.

[0067] (2) 2 mmol of compound 1, 4 mmol of p-hydroxybenzyl cyanide, 8 mmol of anhydrous potassium carbonate and 1 mmol of potassium iodide were added to 50 mL of anhydrous acetonitrile. After refluxing for 24 hours, most of the solvent was evaporated. 50 mL of dichloromethane and 50 mL of 1M hydrochloric acid solution were added, and the mixture was stirred well and separated into layers. The organic layer was dried, concentrated, 50 mL of methanol was added, and the mixture was placed in the refrigerator overnight to fully precipitate the solid. The solid was filtered out and dried to obtain compound 2.

[0068] (3) 2 mmol of compound 1, 4 mmol of p-hydroxybenzaldehyde, 8 mmol of anhydrous potassium carbonate and 1 mmol of potassium iodide were added to 50 mL of anhydrous acetonitrile. After refluxing for 24 hours, most of the solvent was evaporated. 50 mL of dichloromethane and 50 mL of 1M hydrochloric acid solution were added, and the mixture was stirred well and separated into layers. The organic layer was dried, concentrated, 50 mL of methanol was added, and the mixture was placed in the refrigerator overnight to fully precipitate the solid. The solid was filtered out and dried to obtain compound 3.

[0069] (4) In a flask, 1 mmol of compound 2, 1 mmol of compound 3 and 1 mmol of sodium hydroxide were added to 100 mL of 99.5% absolute ethanol, and the mixture was stirred and refluxed for 24 h. After the reaction was completed, a solid was precipitated.

[0070] (5) The solid obtained in step (4) was filtered out, dissolved in 40 mL of chloroform, washed twice with 30 mL of distilled water, and the organic layer was separated. The organic layer was concentrated and subjected to silica gel column chromatography (eluent: ethyl acetate / petroleum ether = 1:3, V / V) to obtain a yellow-green solid, namely the cyanodiphenylstilbene crown ether macrocyclic fluorescent probe (molecular formula: C 84 H 84 N4O 16 ), and the yield was 68%.

[0071] Example 3

[0072] This example provides a method for synthesizing a cyanodiphenylstilbene crown ether macrocyclic fluorescent probe, which includes the following steps:

[0073] (1) Under ice bath conditions, 0.1 mol of triethylene glycol and 0.2 mol of p-toluenesulfonyl chloride were added to 100 mL of anhydrous pyridine, and the mixture was stirred for 8 h. A large amount of white precipitate was formed. After stirring, the reaction mixture was slowly poured into 200 mL of 10% hydrochloric acid, and then 100 mL of dichloromethane solution was added to extract the organic matter. The organic layer was separated, concentrated, methanol was added for precipitation, and a white solid was obtained. After filtration and drying, triethylene glycol bis(p-toluenesulfonate), that is, compound 1, was prepared.

[0074] (2) 2 mmol of compound 1, 4 mmol of p-hydroxybenzyl cyanide, 8 mmol of anhydrous potassium carbonate and 1 mmol of potassium iodide were added to 50 mL of anhydrous acetonitrile. After refluxing for 24 hours, most of the solvent was evaporated. 50 mL of dichloromethane and 50 mL of 1 M hydrochloric acid solution were added, and the mixture was stirred well and separated into layers. The organic layer was separated, dried, concentrated, 50 mL of methanol was added, and the mixture was placed in the refrigerator overnight to fully precipitate the solid. The solid was filtered out and dried to obtain compound 2.

[0075] (3) 2 mmol of compound 1, 4 mmol of p-hydroxybenzaldehyde, 8 mmol of anhydrous potassium carbonate and 1 mmol of potassium iodide were added to 50 mL of anhydrous acetonitrile. After refluxing for 24 hours, most of the solvent was evaporated. 50 mL of dichloromethane and 50 mL of 1 M hydrochloric acid solution were added, and the mixture was stirred well and separated into layers. The organic layer was separated, dried, concentrated, 50 mL of methanol was added, and the mixture was placed in the refrigerator overnight to fully precipitate the solid. The solid was filtered out and dried to obtain compound 3.

[0076] (4) In a flask, 1 mmol of compound 2, 1.5 mmol of compound 3 and 1.5 mmol of sodium hydroxide were added to 100 mL of 99.5% absolute ethanol, and the mixture was stirred and refluxed for 12 h. After the reaction was completed, a solid was precipitated.

[0077] (5) Filter out the solid in step (4), dissolve it with 40 mL of chloroform, wash it twice with 30 mL of distilled water, separate the organic layer, concentrate the organic layer and subject it to silica gel column chromatography (eluent: ethyl acetate / petroleum ether = 1:3, V / V) to obtain a yellowish-green solid, namely the cyanostilbene crown ether macrocyclic fluorescent probe (molecular formula C 84 H 84 N4O 16 ), with a yield of 41%.

[0078] Example 4

[0079] This example provides an application of the cyanostilbene crown ether macrocyclic fluorescent probe, including the following steps:

[0080] (1) Prepare a tetrahydrofuran-water mixed solution containing the cyanostilbene crown ether macrocyclic fluorescent probe of Example 2 above, where the volume ratio of tetrahydrofuran to water is 5:95. Prepare a series of carbendazim solutions with gradient-changing concentrations according to 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 2.0, 3.0, 4.0 times the concentration of the fluorescent probe. Mix the mixed solution with the series of carbendazim solutions respectively, measure the fluorescence intensity after mixing, and establish a standard working curve with the fluorescence intensity on the vertical axis and the carbendazim concentration on the horizontal axis, as Figure 2 shown;

[0081] (2) Mix the tetrahydrofuran-water mixed solution containing the cyanostilbene crown ether macrocyclic fluorescent probe with the carbendazim solution to be tested, compare the measured fluorescence intensity value with the standard working curve in step (1), and read out the carbendazim concentration in the solution to be tested from the curve graph.

[0082] Performance test:

[0083] 1. Selectivity test

[0084] Add 1×10 -5 mol / L of various pesticide molecules to a 1×10 -5 mol / L tetrahydrofuran-water mixed solution containing the cyanostilbene crown ether macrocyclic fluorescent probe described in Example 2, and measure the fluorescence emission spectra after the reaction respectively. The results are as Figure 3 shown.

[0085] As Figure 3 shown, when testing different pesticide molecules, the tetrahydrofuran-water mixed solution containing the cyanostilbene crown ether macrocyclic fluorescent probe only responds quickly to carbendazim and the fluorescence intensity increases significantly, indicating that this fluorescent probe has good selective recognition ability for carbendazim.

[0086] 2. Correlation test

[0087] To a 1×10 -5 mol / L tetrahydrofuran-water mixed solution containing the cyano-distyryl crown ether macrocyclic fluorescent probe described in Example 2, different concentrations of carbendazim solutions were added, and the fluorescence emission spectra after the reaction were measured respectively. The results are as Figure 4 shown.

[0088] Among Figure 4 them, as the concentration of carbendazim in the solution continued to increase, the fluorescence intensity of the tetrahydrofuran-water mixed solution containing the cyano-distyryl crown ether macrocyclic fluorescent probe showed an obvious upward trend. Therefore, it can be inferred that there is a good linear relationship between the fluorescence intensity of this fluorescent probe mixed solution and the concentration of carbendazim, and it can be applied to the quantitative analysis activities related to carbendazim.

[0089] 3. Anti-interference test

[0090] To a 1×10 -5 mol / L tetrahydrofuran-water mixed solution containing the cyano-distyryl crown ether macrocyclic fluorescent probe described in Example 2, 1×10 -5 mol / L of other guests (or other guests + carbendazim) were added, and the fluorescence emission spectra after the reaction were measured respectively. The results are as Figure 5 shown.

[0091] Figure 5 In -5 it, I is the fluorescence intensity after the reaction of a 1×10 -5 mol / L tetrahydrofuran-water mixed solution containing the cyano-distyryl crown ether macrocyclic fluorescent probe with 1×10 o mol / L of other guests (or other guests + carbendazim), and I -5 is the fluorescence intensity of a 1×10 Figure 5 mol / L fluorescent probe mixed solution. It can be seen from

[0092] that after adding other guests, the fluorescence ratios of the fluorescent probe are all close to 1, indicating that other guests have little effect on the fluorescence of the fluorescent probe. However, after adding carbendazim to other ions, the fluorescence of the fluorescent probe is significantly enhanced, indicating that other guests have little interference on the sensitive detection of carbendazim by this fluorescent probe. The above are only the embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structure or equivalent process transformation made by using the content of the specification of the present invention, or directly or indirectly applied in other related technical fields, shall be equally included in the patent protection scope of the present invention.

Claims

1. A cyano-diphenyl ethylene crown ether macrocyclic fluorescent probe, characterized in that, The chemical name of the fluorescent probe is tetra-(4-triethylenedioxyl-1-cyano-1,2-diphenylvinyl) macrocycle, which has a macrocyclic structure with cyanodiphenylethylene as the structural unit bridged by a crown ether chain. The chemical structural formula is shown in (I): Its molecular formula is C 84 H 84 N4O 16 .

2. A method for synthesizing the cyanostilbene crown ether macrocyclic fluorescent probe as described in claim 1, characterized in that, It includes the following steps: (1) Under ice bath conditions, stir triethylene glycol and p-toluenesulfonyl chloride in anhydrous pyridine to precipitate a white solid. Then, slowly pour the whole reaction mixture into hydrochloric acid with stirring, add dichloromethane solution to extract the organic matter, separate the organic layer and concentrate it, add methanol to precipitate, obtain a white solid, and prepare triethylene glycol bis(p-toluenesulfonate), namely Compound 1, after filtration and drying. The chemical structural formula of Compound 1 is shown in (II): (2) Add Compound 1, p-hydroxybenzyl cyanide, anhydrous potassium carbonate, and potassium iodide to anhydrous acetonitrile for reflux. After most of the solvent is evaporated, add dichloromethane and hydrochloric acid solution, stir well and separate the layers. After separating the organic layer, dry it, concentrate it, add methanol, and place it in the refrigerator overnight to fully precipitate the solid. Filter out the solid and dry it to obtain Compound 2. The chemical structural formula of Compound 2 is shown in (III): (3) Add Compound 1, p-hydroxybenzaldehyde, anhydrous potassium carbonate, and potassium iodide to anhydrous acetonitrile, reflux and then evaporate most of the solvent, add dichloromethane and hydrochloric acid solution, stir well and separate the layers. After separating the organic layer, dry it, concentrate it, add methanol, and place it in the refrigerator overnight to fully precipitate the solid. Filter out the solid and dry it to obtain Compound 3. The chemical structural formula of Compound 3 is shown in (IV): (4) Under the protection of a nitrogen atmosphere, stir and reflux Compound 2, Compound 3, and sodium hydroxide in anhydrous ethanol in a flask. After the reaction ends, a solid precipitates; (5) Filter out the solid in step (3), dissolve it with chloroform, wash it with distilled water to separate the organic layer, concentrate the organic layer and perform silica gel column chromatography to obtain a yellow-green solid, namely the cyanodiphenylethylene crown ether macrocycle fluorescent probe.

3. The synthesis method of a cyano-distyryl crown ether macrocyclic fluorescent probe as claimed in claim 2, wherein, In step (1), the molar ratio of triethylene glycol to p-toluenesulfonyl chloride is 1:2; the mass fraction of hydrochloric acid is 10%.

4. The synthesis method of a cyano-distyryl crown ether macrocyclic fluorescent probe according to claim 2, characterized in that, In step (2), the molar ratio of Compound 1, p-hydroxybenzyl cyanide, anhydrous potassium carbonate, and potassium iodide is 2:4:8:1, and the molar concentration of hydrochloric acid is 1 mol / L.

5. The synthesis method of a cyano-diphenyl ethylene crown ether macrocyclic fluorescent probe according to claim 2, characterized in that, In step (3), the molar ratio of Compound 1, p-hydroxybenzaldehyde, anhydrous potassium carbonate, and potassium iodide is 2:4:8:

1.

6. The synthesis method of a cyano-distyryl crown ether macrocyclic fluorescent probe according to claim 2, characterized in that, In step (3), the molar concentration of hydrochloric acid is 1 mol / L.

7. The synthesis method of a cyano-distyryl crown ether macrocyclic fluorescent probe as claimed in claim 2, wherein In step (4), the molar ratio of Compound 2, Compound 3, and sodium hydroxide is 1:0.5 - 1.5:0.5 - 1.

5.

8. The synthesis method of a cyano-distyryl crown ether macrocyclic fluorescent probe as described in claim 2, characterized in that, In step (4), the stirring and reflux time is 12 - 36 h.

9. The synthesis method of a cyano-distyryl crown ether macrocyclic fluorescent probe according to claim 2, characterized in that, In step (5), when performing silica gel column chromatography separation, the eluent is a mixed solution of ethyl acetate and petroleum ether with a volume ratio of 1:

3.

10. Application of the cyanodiphenylethylene crown ether macrocycle fluorescent probe as described in claim 1 in detecting carbendazim.

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