Fluorescent probe based on tetraphenylimidazole Schiff base as well as preparation method and application of fluorescent probe

Abstract

The invention discloses a tetraphenylimidazole Schiff base-based fluorescent probe and a preparation method and application thereof, the chemical name of the tetraphenylimidazole Schiff base-based fluorescent probe is (E)-2-(((2-hydroxyphenyl) imino) methyl)-4-(1, 4, 5-triphenyl-1H-imidazole-2-yl), the molecular formula of the tetraphenylimidazole Schiff base-based fluorescent probe is C34H25N3O2, and the structural formula of the tetraphenylimidazole Schiff base-based fluorescent probe is shown in the description. The fluorescence sensor can form a mixture with the combination ratio of 1: 1 with quizalofop-p-ethyl in a dimethylsulfoxide-water mixed solution, the fluorescence intensity is obviously enhanced, the enhancement trend of the fluorescence intensity is in direct proportion to the concentration of quizalofop-p-ethyl within a certain range, and the fluorescence sensor can be used for sensitive detection of quizalofop-p-ethyl in an environment or a real sample and has a good application prospect. The fluorescent probe is an ideal fluorescent probe for rapidly detecting quizalofop-p-ethyl.

Description

Technical Field

[0001] The present invention relates to a fluorescent probe based on tetraphenylimidazole Schiff base, its preparation method and application, belonging to the technical fields of organic synthesis and analytical chemistry. Background Art

[0002] With the rapid development of agriculture, pesticides play an increasingly crucial role in crop planting, storage and protection of agricultural products, etc. Using pesticides can effectively reduce the number of pests or weeds and increase the yield of agricultural products. However, the overuse of pesticides will lead to pesticide residues. Even trace amounts of pesticide residues can cause food pollution and serious damage to the ecological environment. At the same time, most pesticides have high water solubility and high stability, are easy to flow into the soil and water, and finally enter the human body through the food chain, posing a great threat to human life safety. Therefore, the problem of pesticide pollution has attracted more and more attention.

[0003] Organochlorine pesticides (abbreviated as OCPs) are an important class of pesticides, which are widely used for insecticidal, bactericidal, termite control and weeding. They have strong anti-decomposability and can remain in the environmental ecosystem for a long time. For example, the half-life of the pesticide dichlorodiphenyldichloroethylene (DDE) in the soil exceeds 20 years. In addition, organochlorine pesticides have high solubility in animal fat and can accumulate in biological tissues over time. Long-term exposure to them has a significant impact on human health. Many studies have shown that there is a potential association between the residue or pollution problems of organochlorine pesticides and diseases such as leukemia, lymphoma and human cancers (such as breast cancer, lung cancer, skin cancer, pancreatic cancer, liver cancer).

[0004] In recent years, the most commonly used detection methods in pesticide detection technology are instrumental analysis methods such as gas chromatography-mass spectrometry (GC), high performance liquid chromatography (HPLC) and gas chromatography-tandem mass spectrometry (GC-MS). Although the above methods have the characteristics of high selectivity and high sensitivity, they also have problems such as complex sampling technology, cumbersome operation process, high technical requirements for testers, and high instrument costs. Organic fluorescent probe detection has attracted much attention due to its advantages such as low detection limit, high sensitivity, simple operation and fast response speed. At present, different types of fluorescence have been developed to achieve selective detection of pesticide residues, but there are few fluorescent probes for the detection of organochlorine pesticides. Therefore, there is an urgent need for a simple, rapid and easy-to-use fluorescent probe detection method to achieve highly sensitive and selective detection of residual organochlorine pesticides in the environment. Summary of the Invention

[0005] The present invention provides a fluorescent probe based on tetraphenylimidazole Schiff base, which can have an obvious "turn-on" type dark green fluorescence change after responding to quizalofop-ethyl in an aqueous medium, and realizes detection through obvious fluorescence enhancement, and has high sensitivity and selective sensing ability for quizalofop-ethyl.

[0006] The technical solution of the present invention is as follows:

[0007] The present invention provides a fluorescent probe based on tetraphenylimidazole Schiff base, with the molecular formula C 34 H 25 N3O2, having the structure shown below:

[0008]

[0009] The present invention also provides a preparation method of a fluorescent probe based on tetraphenylimidazole Schiff base. Under a nitrogen atmosphere, using 2-hydroxy-5-(1,4,5-triphenyl-1H-imidazol-2-yl)benzaldehyde and o-aminophenol as raw materials, after mixing them, dissolve them in absolute ethanol and stir and reflux for 5 - 15 h until the raw materials react completely. Cool the reaction solution to room temperature, add ice-cold pure water to the reaction solution and collect the red precipitate. Recrystallize the red precipitate in CHCl3 / MeOH to obtain red C 34 H 25 N3O2, which is the fluorescent probe based on tetraphenylimidazole Schiff base.

[0010] Furthermore, the molar ratio of 2-hydroxy-5-(1,4,5-triphenyl-1H-imidazol-2-yl)benzaldehyde to o-aminophenol is 1:1 - 5.

[0011] Furthermore, the volume ratio of CHCl3 / MeOH is 1:5.

[0012] The present invention also provides the use of the fluorescent probe based on tetraphenylimidazole Schiff base for detecting quizalofop-p-ethyl.

[0013] Furthermore, the fluorescent probe based on tetraphenylimidazole Schiff base forms a mixture with a binding ratio of 1:1 with quizalofop-p-ethyl in a dimethyl sulfoxide-water mixed solution, enhancing fluorescence.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0015] 1. The fluorescence probe (TPS) provided by the present invention has obvious cyan fluorescence at 485 nm in a dimethyl sulfoxide solution system; in a dimethyl sulfoxide - water (V / V, 5:95) mixed solution, the probe has dual fluorescence emissions at 483 nm and 558 nm and emits weak purplish - red fluorescence; the fluorescence probe of the present invention can form a mixture with quizalofop - p - ethyl with a binding ratio of 1:1 in a dimethyl sulfoxide - water (V / V, 5:95) mixed solution, the fluorescence intensity is significantly enhanced, and within a certain range, the increasing trend of the fluorescence intensity is proportional to the concentration of quizalofop - p - ethyl. The presence of other types of guests does not interfere with the detection of quizalofop - p - ethyl. Therefore, the fluorescence probe of the present invention can be used for the sensitive detection of quizalofop - p - ethyl in environmental or real samples and is an ideal fluorescence probe for the rapid detection of quizalofop - p - ethyl.

[0016] 2. The detection limit of the fluorescence probe provided by the present invention is 0.0096 μM, which can be used for the selective and sensitive detection of quizalofop - p - ethyl and has good application prospects for the detection of quizalofop - p - ethyl in complex environments and real samples. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is the infrared spectrum diagram of the functional group structures of TPS of the present invention;

[0018] Figure 2 It is the nuclear magnetic resonance hydrogen spectrum diagram of the structure of TPS of the present invention;

[0019] Figure 3 It is the nuclear magnetic resonance carbon spectrum diagram of the structure of TPS of the present invention;

[0020] Figure 4 It is the mass spectrum diagram of the structure of TPS of the present invention;

[0021] Figure 5 It is the fluorescence spectrum diagram after the compound TPS with a concentration of 1×10 -5 mol / L is mixed with different concentrations of quizalofop - p - ethyl in a dimethyl sulfoxide - aqueous solution (V / V, 5:95);

[0022] Figure 6 It is the standard curve of the change in the concentration gradient of quizalofop - p - ethyl and the change in fluorescence intensity in Example 4;

[0023] Figure 7 It is the fluorescence emission spectrum diagram after the compound TPS with a concentration of 1×10 -5 mol / L is mixed with various pesticides and ions with a concentration of 1×10 -5 mol / L in a dimethyl sulfoxide - aqueous solution (V / V, 5:95);

[0024] Figure 8Schematic diagram of the fluorescence intensity ratio of compound TPS + quizalofop-p-ethyl + other molecules to compound TPS + quizalofop-p-ethyl in dimethyl sulfoxide - aqueous solution (V / V, 5:95). Detailed implementation mode

[0025] The following further describes the present invention in conjunction with preferred embodiments. In the present invention, the endpoints and any values within the disclosed ranges are not limited to the exact ranges or values, and these ranges or values should be understood to include values close to these ranges or values; for numerical ranges, between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values, they can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0026] The experimental methods in the following examples are all conventional methods unless otherwise specified, and are carried out according to the techniques or conditions described in the literature in this field or according to the product instructions. The materials, reagents, etc. used in the following examples can be obtained from commercial channels unless otherwise specified.

[0027] The present invention provides a fluorescence probe based on tetraphenylimidazole Schiff base. According to Figure 1 the infrared spectrum shown, Figure 2 the nuclear magnetic resonance hydrogen spectrum shown, Figure 3 the nuclear magnetic resonance carbon spectrum shown, Figure 4 and the mass spectrum shown, the fluorescence probe of the present invention is named (E)-2-(((2-hydroxyphenyl)imino)methyl)-4-(1,4,5-triphenyl-1H-imidazol-2-yl)phenol, which is abbreviated as TPS in the following examples. Its molecular formula is C 34 H 25 N3O2, and has the following structure:

[0028]

[0029] The nuclear magnetic resonance hydrogen spectrum of TPS is: 1 H NMR(400MHz,DMSO-d6),δppm:6.77(d,J=12.0Hz,1H,ArH),6.88(t,J=8.0Hz,1H,ArH),6.96(d,J=8.0Hz,1H,ArH),7.12-7.19(m,3H,ArH),7.23-7.38(m,13H,ArH),7.51(d,J=8.0Hz,2H,ArH),7.85(d,J=4.0Hz,1H,ArH),8.91(s,1H,N=CH),9.79(s,1H,OH),14.08(s,1H,OH);

[0030] The carbon-13 NMR spectrum of TPS is as follows: 13 C NMR(100MHz,DMSO-d6),δ,ppm:117.0,119.6,120.1,121.6,126.8,126.9,128.6,128.8,128.9,129.2,129.7,130.9,131.3,131.6,132.7,133.1,134.8,134.9,137.1,146.1,151.6,161.5,161.6;MALDI-TOF-MS m / z:Calcd forC 34 H 25 N3O2[M+K] + ,546.295,found:546.363.Anal.calcd for C 34 H 25 N3O2:C 80.45;H 4.96;N8.28;found C 80.48,H 4.92,N 8.31.

[0031] Example 1

[0032] This example provides a preparation method of a fluorescent probe based on tetraphenylimidazole Schiff base, and the steps are as follows:

[0033] Under a nitrogen atmosphere, 0.50 mol of 2-hydroxy-5-(1,4,5-triphenyl-1H-imidazol-2-yl)benzaldehyde and 0.50 mol of o-aminophenol are used as raw materials. After mixing, they are dissolved in 10 mL of anhydrous ethanol with a mass concentration of 99% and stirred and refluxed for 15 h. The reaction process is monitored by TLC thin-layer chromatography until the raw materials react completely. The reaction solution is cooled to room temperature, 100 mL of ice-cold pure water is added to the reaction solution, and the red precipitate is collected. The red precipitate is recrystallized in CHCl3 / MeOH (volume ratio of 1:5) to obtain red C 34 H 25 N3O2, which is the fluorescent probe based on tetraphenylimidazole Schiff base. After detection, the yield is 80.5%.

[0034] Among them, in this example and the following examples, the raw material 2-hydroxy-5-(1,4,5-triphenyl-1H-imidazol-2-yl)benzaldehyde is prepared according to the method in the public literature "Sens.Actuators B:Chem.2022,369:132347.".

[0035] Example 2

[0036] This example provides a preparation method of a fluorescent probe based on tetraphenylimidazole Schiff base, and the steps are as follows:

[0037] Under a nitrogen atmosphere, 0.50 mol of 2-hydroxy-5-(1,4,5-triphenyl-1H-imidazol-2-yl)benzaldehyde and 2.50 mol of o-aminophenol were used as raw materials. After mixing them, they were dissolved in 20 mL of anhydrous ethanol with a mass concentration of 99% and stirred under reflux for 5 h. The reaction progress was monitored by TLC thin-layer chromatography until the raw materials reacted completely. The reaction solution was cooled to room temperature, 200 mL of ice-cold pure water was added to the reaction solution, and the red precipitate was collected. The red precipitate was recrystallized in CHCl3 / MeOH (volume ratio 1:5) to obtain red C 34 H 25 N3O2, which is the fluorescent probe based on tetraphenylimidazole Schiff base. The yield was detected to be 92.5%.

[0038] Example 3

[0039] This example provides a preparation method of a fluorescent probe based on tetraphenylimidazole Schiff base, and the steps are as follows:

[0040] Under a nitrogen atmosphere, 0.50 mol of 2-hydroxy-5-(1,4,5-triphenyl-1H-imidazol-2-yl)benzaldehyde and 1.50 mol of o-aminophenol were used as raw materials. After mixing them, they were dissolved in 15 mL of anhydrous ethanol with a mass concentration of 99% and stirred under reflux for 10 h. The reaction progress was monitored by TLC thin-layer chromatography until the raw materials reacted completely. The reaction solution was cooled to room temperature, 150 mL of ice-cold pure water was added to the reaction solution, and the red precipitate was collected. The red precipitate was recrystallized in CHCl3 / MeOH (volume ratio 1:5) to obtain red C 34 H 25 N3O2, which is the fluorescent probe based on tetraphenylimidazole Schiff base. The yield was detected to be 86.8%.

[0041] Example 4

[0042] The compound TPS provided by the present invention was used as a fluorescent probe to detect quizalofop-p-ethyl, and the specific steps are as follows:

[0043] The compound TPS was formulated into a solution with a certain concentration. At the same time, a series of quizalofop-p-ethyl solutions with gradient-changing concentrations were prepared according to 0, 0.01, 0.02, 0.04, 0.06, 0.08, 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, and 5.0 molar multiples of the concentration of the compound TPS. The compound TPS was fully shaken and mixed with these series of quizalofop-p-ethyl solutions one by one, and the fluorescence intensity of the mixed solution was measured. The fluorescence intensity spectrum of the measured quizalofop-p-ethyl is shown in Figure 5. As can be seen from the figure, the fluorescence intensity of the compound TPS shows an obvious increasing trend as the concentration of quizalofop-p-ethyl increases. Taking Figure 5Based on this, a standard curve of the concentration gradient change of quizalofop-p-ethyl was established with the quizalofop-p-ethyl concentration as the abscissa and the fluorescence intensity of the mixed solution as the ordinate. As Figure 6 shown, the increasing trend of the fluorescence intensity of the compound TPS and quizalofop-p-ethyl mixed system is linearly related to the quizalofop-p-ethyl concentration. Comparing the obtained fluorescence intensity values with the standard curve of the concentration gradient change of quizalofop-p-ethyl established above, the content of quizalofop-p-ethyl in the quizalofop-p-ethyl solution with unknown concentration can be read from the curve graph.

[0044] Figure 7 In dimethyl sulfoxide-aqueous solution (V / V, 5:95), the fluorescence emission spectra of compound TPS with a concentration of 1×10 -5 M and various common pesticides and ions with a concentration of 1×10 -5 M are mixed, as Figure 7 shown. The compounds, common pesticides and ions (test objects) indicated by each serial number in the figure are as follows: 1 = TPS, 2 = 1 + quizalofop-p-ethyl, 3 = 1 + bromoxynil octanoate, 4 = 1 + thiophanate-methyl, 5 = 1 + oxyfluorfen, 6 = 1 + pymetrozine, 7 = 1 + naphthaleneacetic acid, 8 = 1 + hexazinone, 9 = 1 + thiamethoxam, 10 = 1 + dimehypo, 11 = 1 + triadimefon, 12 = 1 + monosultap, 13 = 1 + paraldehyde, 14 = 1 + Na + +, 15 = 1 + K + +, 16 = 1 + Zn 2 + 2+, 17 = 1 + Ca 2+ 2+, 18 = 1 + NH 4+ 4+, 19 = 1 + Ba 2+ 2+, 20 = 1 + Pb 2+ 2+, 21 = 1 + Hg 2+ 2+, 22 = 1 + Cu 2+ 2+, 23 = 1 + SO4 2- 2-, 24 = 1 + NO3 - -, 25 = 1 + Cl - -, 26 = 1 + PO4 3 3-, 27 = 1 + HPO4 2- 2-. Under the influence of various other molecules, compound TPS only has an obvious response phenomenon to quizalofop-p-ethyl and the fluorescence is significantly enhanced, indicating that compound TPS can selectively recognize quizalofop-p-ethyl.

[0045] Figure 8Schematic diagram of the fluorescence intensity ratio of compound TPS + quizalofop - p - ethyl + other molecules to compound TPS + quizalofop - p - ethyl in dimethyl sulfoxide - aqueous solution (V / V, 5:95). The ordinate is the fluorescence intensity of each test object, and the abscissa is the test object. The test objects represented by serial numbers from left to right (0 - 26) are as follows: 1 = TPS + quizalofop - p - ethyl, 2 = 1 + bromoxynil octanoate, 3 = 1 + thiophanate - methyl, 4 = 1 + oxyfluorfen, 5 = 1 + pymetrozine, 6 = 1 + naphthaleneacetic acid, 7 = 1 + hexazinone, 8 = 1 + thiamethoxam, 9 = 1 + dimehypo, 10 = 1 + triadimefon, 11 = 1 + monosultap, 12 = 1 + paraldehyde, 13 = 1 + Na + ,14 = 1 + K + ,15 = 1 + Zn 2+ ,16 = 1 + Ca 2+ ,17 = 1 + NH4 + ,18 = 1 + Ba 2+ ,19 = 1 + Pb + ,20 = 1 + Hg 2+ ,21 = 1 + Cu 2 + ,22 = 1 + SO4 2- ,23 = 1 + NO3 - ,24 = 1 + Cl - ,25 = 1 + PO4 3- ,26 = 1 + HPO4 2- ; In this example, the concentration of compound TPS is 1×10 -5 M, and the concentration after adding other interfering objects in mixture is 2×10 -5 M. As can be seen from Figure 8 , the change in fluorescence intensity during the test is not significant, indicating that other object molecules do not interfere with the detection of quizalofop - p - ethyl by the fluorescence probe of the present invention.

[0046] The above - mentioned embodiments are all preferred embodiments of the present invention. However, the embodiments of the present invention are not limited to the above - mentioned embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of this patent shall be equivalent replacement methods and are all included in the protection scope of this patent.

Claims

1. A fluorescent probe based on tetraphenylimidazole Schiff base, characterized in that: Its molecular formula C 34 H 25 N3O2 has the following structure:

2. The method for preparing a fluorescent probe based on tetraphenylimidazole Schiff base according to claim 1, characterized in that: Under nitrogen atmosphere, 2-hydroxy-5-(1,4,5-triphenyl-1H-imidazole-2-yl)benzaldehyde and o-aminophenol were used as raw materials, mixed and dissolved in anhydrous ethanol and stirred under reflux for 5 to 15 hours until the raw materials reacted completely, the reaction solution was cooled to room temperature, ice-pure water was added to the reaction solution and the red precipitate was collected, and the red precipitate was recrystallized in CHCl3 / MeOH to obtain red C 34 H 25 N3O2 is a fluorescent probe based on tetraphenylimidazole Schiff base.

3. The method for preparing a fluorescent probe based on tetraphenylimidazole Schiff base according to claim 2, characterized in that: The molar ratio of 2-hydroxy-5-(1,4,5-triphenyl-1H-imidazol-2-yl)benzaldehyde to o-aminophenol is 1:1-5.

4. The method for preparing a fluorescent probe based on tetraphenylimidazole Schiff base according to claim 2, characterized in that: The volume ratio of CHCl3 / MeOH was 1:

5. The tetraphenylimidazole Schiff base-based fluorescent probe as claimed in claim 1 is used to detect quizalofop-ethyl.

6. The fluorescent probe based on tetraphenylimidazole Schiff base according to claim 5 is used to detect Quizalofop-P-ethyl, characterized in that: The fluorescent probe based on tetraphenylimidazole Schiff base forms a mixture with a binding ratio of 1:1 with quizalofop-ethyl in a mixed solution of dimethyl sulfoxide-water, enhancing fluorescence.

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