Fluorescent probe based on 2, 5-dioctyl-3, 6-diphenyl pyrrolo-pyrrolo-dione and preparation method thereof

Abstract

The invention belongs to the technical field of probe detection, and particularly relates to a fluorescent probe based on 2, 5-dioctyl-3, 6-diphenyl pyrrolo-pyrrolo-dione and a preparation method of the fluorescent probe based on 2, 5-dioctyl-3, 6-diphenyl pyrrolo-pyrrolo-dione. In order to overcome the technical defects that an existing instrument is expensive and complex to operate, the invention provides a novel fluorescent probe based on 2, 5-dioctyl-3, 6-diphenyl pyrrolo-pyrrolo-dione. An aldehyde group is introduced to 2, 5-dioctyl-3, 6-diphenyl pyrrolo-pyrrolo-diketone, and different fluorescent probes are constructed through reaction of the aldehyde group and different recognition groups, so that detection of specific substances is realized.

Description

Technical Field

[0001] The present application belongs to the field of fluorescent probes, and specifically relates to a fluorescent probe based on 2,5-dioctyl-3,6-diphenylpyrrolopyrrole dione and a preparation method thereof. Background Art

[0002] The advantage of fluorescent probes in the field of detection is that they can identify specific chemicals with extremely high sensitivity and selectivity, and convert these microscopic identification information into intuitive fluorescent signals, allowing accurate detection of target substances in complex biological samples. The use of fluorescent probes is easy to operate, low cost and high efficiency, and suitable for widespread application in laboratories. In addition, fluorescence imaging technology has a place in the field of biomedical imaging due to its high spatial resolution and can provide precise positioning information. The multi-channel detection capability of fluorescent probes makes it possible to detect multiple targets simultaneously in the same reaction system, improving the efficiency and accuracy of the experiment.

[0003] Diketopyrrolopyrrole (DPP) is an organic compound with a conjugated structure, consisting of two pyrrole rings connected by a diketo group. It has excellent photoelectric properties, high molar absorption coefficient, good charge transfer ability, chemical structure modifiability, and good photostability and thermal stability. Due to its unique chemical and physical properties, it has shown a wide range of application prospects in the field of scientific research, including its application as an organic luminescent material in bioimaging and chemical sensors, its potential as a photosensitizer and photothermal agent in tumor treatment, its use as a high-performance material in organic field-effect transistors and organic photovoltaic devices, and its potential applications in sensors, light-absorbing materials, lithium-sulfur batteries, and optoelectronic devices.

[0004] Mercury ion (Hg 2+ ) is one of the most toxic heavy metal pollutants, which can cause serious environmental and health problems. 2+ It is easily absorbed by plants and accumulated through the food chain and converted into more dangerous organic mercury, especially methylmercury. This form of mercury is extremely destructive to the human nervous system and may cause symptoms such as neurasthenia, memory loss, poor sleep quality, and emotional instability. Mercury also has direct damage to the kidneys. High concentrations of mercury can directly damage renal tubular cells and cause acute tubular necrosis. Long-term exposure may also lead to nephrotic syndrome.

[0005] Endogenous hypochlorous acid (HClO) in organisms mainly comes from the oxidation reaction of hydrogen peroxide and chloride ions catalyzed by myeloperoxidase (MPO) in neutrophils. Neutrophils, as an important part of the immune system, participate in the body's immune defense mechanism. HClO and hypochlorite ions (ClO -) is essential for clearing invading bacteria and viruses and participating in life activities such as cell differentiation and migration when it maintains a normal concentration. - When the content is too high, it may damage nucleic acids, proteins, lipids, etc. in cells through oxidation or chlorination, causing cell apoptosis and tissue damage, which is related to the occurrence of diseases such as acute lung injury, cardiovascular disease, neurodegenerative diseases and even cancer. Therefore, it is necessary to develop accurate and reliable HClO / ClO - Detection methods are of great significance to life science and medical research.

[0006] Hydrazine hydrate (N2H4·H2O) is a colorless oily liquid with a light ammonia smell. It will smoke in the air and show a pungent smell. It occupies an important position in the chemical industry due to its strong nucleophilicity and reducing properties. It is widely used as aviation rocket and jet engine fuel, dye, antioxidant, catalyst, polymer cross-linking agent, etc. In addition, hydrazine hydrate is also used in synthetic industries such as pharmaceutical and pesticide synthesis, plastic foaming agent, etc. Hydrazine hydrate poses a serious threat to the environment and human health due to its high toxicity, high active alkalinity and good water solubility. It can enter the human body through inhalation, skin contact or ingestion, destroy DNA sequences, damage the lungs, liver and central nervous system, etc., causing irreversible damage. Studies have shown that the high toxicity of hydrazine hydrate may be related to its easy oxidation into chemically active substances, which can denature proteins, further damage the liver system, and even cause death. Summary of the invention

[0007] In order to overcome the technical defects of the existing instruments, which are expensive and complicated to operate, the present application provides a new fluorescent probe based on 2,5-dioctyl-3,6-diphenylpyrrolopyrrole dione. An aldehyde group is introduced into 2,5-dioctyl-3,6-diphenylpyrrolopyrrole dione, and three fluorescent probes HG1, DPP-1 and DPP-2 are synthesized through the reaction of the aldehyde group with ethanethiol, diaminomaleonitrile and malononitrile, and the detection of specific substances is realized.

[0008] The present application provides three fluorescent probes HG1, DPP-1 and DPP-2 based on 2,5-dioctyl-3,6-diphenylpyrrolopyrrole dione, which have good fluorescence properties and can realize simple, efficient and specific detection of specific substances.

[0009] A fluorescent probe based on 2,5-dioctyl-3,6-diphenylpyrrolopyrrole dione, the specific structure of which is as follows:

[0010]

[0011] The synthetic route is as follows:

[0012]

[0013] A fluorescent probe based on 2,5-dioctyl-3,6-diphenylpyrrolopyrrole dione was prepared as follows:

[0014] 1) Weigh 4-cyanobenzaldehyde, aminosulfonic acid and ethylene glycol and dissolve them in cyclohexane. After reflux reaction for 10-12 hours, cool to room temperature, extract the reaction solution with dichloromethane, wash with saturated sodium bicarbonate solution and water, remove water from the organic phase with anhydrous magnesium sulfate, filter and rotary evaporate to obtain a crude product, recrystallize the crude product with ethanol, filter and dry to obtain compound 1;

[0015] 2) Weigh ethyl benzoylacetate and ethyl chloroacetate and dissolve them in a solvent, add anhydrous potassium carbonate and sodium iodide, heat to 60-75°C, react for 10-14 hours, cool to room temperature, filter, extract the filtrate with dichloromethane, wash with water three times, remove water from the organic phase with anhydrous magnesium sulfate, filter, rotary evaporate, and dry to obtain compound 2;

[0016] 3) Weigh ammonium acetate, add it to glacial acetic acid under nitrogen, heat to 65-75°C, stir until completely dissolved, add compound 2 obtained in step 2), react for 20-24 hours, cool to room temperature, pour the reaction solution into ice water, let stand for 15 minutes, filter with suction, wash with water 3 times, recrystallize with ethanol, filter with suction, and dry to obtain compound 3;

[0017] 4) Weighing metallic sodium, adding it to anhydrous tert-amyl alcohol under nitrogen environment, heating to 95-105° C., reacting until sodium is completely dissolved, reducing the temperature to 50-60° C., adding compound 1 obtained in step 1) and compound 3 obtained in step 3), heating to 95-105° C., reacting for 10-14 hours, cooling to room temperature, adding methanol and acetic acid, stirring at room temperature for 1-2 hours, filtering, repeatedly washing with methanol and water until the filtrate is colorless, and drying to obtain compound 4;

[0018] 5) Weigh potassium tert-butoxide and compound 4 obtained in step 4), add them to anhydrous N-methylpyrrolidone under nitrogen environment, heat to 55-65° C., stir until the solution turns red, add n-octane bromide, react for 20-24 hours, cool to room temperature, filter with suction, wash the filter residue with dichloromethane, combine the filtrate and dichloromethane, wash with concentrated brine and water, remove water from the organic phase with anhydrous magnesium sulfate, filter with suction, rotary evaporate, separate by column chromatography, and dry to obtain compound 5;

[0019] 6) Weigh the compound 5 obtained in step 5) and dissolve it in 30 ml of tetrahydrofuran, add 0.02 mol / L hydrochloric acid, reflux for 10-12 hours, cool to room temperature, extract the reaction solution with dichloromethane, wash with water three times, remove water from the organic layer with anhydrous magnesium sulfate, filter, and rotary evaporate to obtain a crude product, which is recrystallized with ethanol, filtered, and dried to obtain compound 6;

[0020] 7) Weigh ethanethiol, boron trifluoride etherate and compound 6 obtained in step 6), add them to anhydrous dichloromethane under nitrogen protection, react at 0° C. for 6-8 hours, warm to room temperature, and rotary evaporate the reaction solution to obtain a crude product, separate by column chromatography, and dry to obtain compound HG1;

[0021] 8) Weigh diaminomaleonitrile and compound 6 obtained in step 6) and dissolve them in anhydrous ethanol. After reflux reaction for 8-10 hours, cool to room temperature, place in a refrigerator for crystallization overnight, filter, wash with cold ethanol, and dry to obtain compound DPP-1;

[0022] 9) Weigh malononitrile and compound 6 obtained in step 6) and dissolve them in anhydrous ethanol. After reflux reaction for 10-12 hours, cool to room temperature, place in a refrigerator for crystallization overnight, filter, wash with cold ethanol, and dry to obtain compound DPP-2.

[0023] In step 1), the molar ratio of 4-cyanobenzaldehyde to ethylene glycol is 1:5 to 1:8; the molar ratio of 4-cyanobenzaldehyde to aminosulfonic acid is 100:8 to 100:10; the organic phase is first washed with saturated sodium bicarbonate for 1 to 2 times, and then washed with water for 2 to 3 times; a water separator needs to be installed during the reaction.

[0024] In step 2), the molar ratio of ethyl benzoylacetate to ethyl chloroacetate is 1:1-1:2; the molar ratio of ethyl benzoylacetate to anhydrous potassium carbonate is 1:1-1:2; the molar ratio of ethyl benzoylacetate to sodium iodide is 5:1-5:2; the solvent is ethylene glycol dimethyl ether and acetone, and the volume ratio of ethylene glycol dimethyl ether to acetone is 1:2-1:3.

[0025] In step 3), add 2-3 g of ammonium acetate to every 10 ml of glacial acetic acid.

[0026] In step 4), 0.2-0.3 g of metallic sodium is added to every 10 ml of anhydrous tert-amyl alcohol; the molar ratio of compound 3 to metallic sodium is 1:6-1:10; the molar ratio of compound 3 to compound 1 is 1:1-1:1.5; and the volume ratio of acetic acid to methanol is 1:15-1:20.

[0027] In step 5), the molar ratio of compound 4 to potassium tert-butoxide is 1:2 to 1:3; the molar ratio of compound 4 to n-octane bromide is 1:5 to 1:8; the concentrated brine is prepared by adding 1 to 2 g of sodium chloride per 10 ml of pure water; the organic phase is first washed with concentrated brine for 4 to 6 times, and then washed with water for 4 to 6 times; in column chromatography separation, n-octane bromide is first washed with a large amount of petroleum ether, and then eluted with ethyl acetate and petroleum ether, and the volume ratio of ethyl acetate to petroleum ether is 3:10.

[0028] In step 6), the volume ratio of 0.02 mol / L hydrochloric acid to tetrahydrofuran is 1:2 to 1:3.

[0029] In step 7), the molar ratio of compound 6 to ethyl mercaptan is 1:2 to 1:2.5; the molar ratio of boron trifluoride ether to ethyl mercaptan is 1:1 to 1:2; and the column chromatography is eluted with ethyl acetate and petroleum ether, and the volume ratio of ethyl acetate to petroleum ether is 3:10.

[0030] In step 8), the molar ratio of compound 6 to diaminomaleonitrile is 1:1 to 1:2.

[0031] In step 9), the molar ratio of compound 6 to malononitrile is 1:1 to 1:2.

[0032] The fluorescent probe based on 2,5-dioctyl-3,6-diphenylpyrrolopyrrole dione is used in the preparation of mercury ion fluorescent probes, hypochlorite ion fluorescent probes and hydrazine hydrate fluorescent probes.

[0033] Beneficial Effects

[0034] The invention synthesizes three compounds HG1, DPP-1 and DPP-2 based on 2,5-dioctyl-3,6-diphenylpyrrolopyrrole dione.

[0035] Hg 2+ The dithioacetal protecting group in compound HG1 can be selectively removed to convert the dithioacetal in the structure of compound HG1 into an aldehyde group and generate compound 6. The reaction is as follows:

[0036]

[0037] After testing, compound HG1 has the ability to inhibit Hg 2+ Good selectivity, can be applied to Hg 2+ Detection field.

[0038] C1O - It can selectively undergo a nucleophilic addition reaction with -C=N- in the compound DPP-1, followed by a hydrolysis reaction and an elimination reaction to generate an aldehyde and produce compound 6. The reaction is as follows:

[0039]

[0040] After testing, the compound DPP-1 has the ability to inhibit ClO - Good selectivity, can be applied to ClO - Detection field.

[0041] N2H4 can selectively attack the malononitrile part of the compound DPP-2 with strong electron-withdrawing ability to generate the corresponding hydrazone. The reaction is as follows:

[0042]

[0043] After testing, the compound DPP-2 has good selectivity for hydrazine hydrate and can be used in the field of hydrazine hydrate detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] (1) Figure 1 is the H NMR spectrum of compound HG1;

[0045] (2) Figure 2 is the mass spectrum of compound HG1;

[0046] (3) Figure 3 is the fluorescence spectrum of compound HG1's selectivity for metal ion mercury (the abscissa is the emission wavelength, the ordinate is the fluorescence intensity);

[0047] (4) Figure 4 This is the anti-interference experimental diagram of compound HG1 detecting mercury ions;

[0048] (5) Figure 5 It is compound HG1, compound HG1+Hg 2+ , H spectrum comparison of compound 6;

[0049] (6) Figure 6 is the H NMR spectrum of compound DPP-1;

[0050] (7) Figure 7 is the mass spectrum of compound DPP-1;

[0051] (8) Figure 8 It is the fluorescence spectrum of the compound DPP-1 selective for hypochlorite (the abscissa is the emission wavelength, and the ordinate is the fluorescence intensity);

[0052] (9) Fig. 9 This is the anti-interference experimental diagram of the compound DPP-1 detecting hypochlorite ions;

[0053] (10) Fig.10 It is compound DPP-1, compound DPP-1+ClO - , H spectrum comparison of compound 6;

[0054] (11) Fig.11 is the H NMR spectrum of compound DPP-2;

[0055] (12) Fig.12 is the mass spectrum of compound DPP-2;

[0056] (13) Fig.13 It is the fluorescence spectrum of the selectivity of compound DPP-2 to hydrazine hydrate (the abscissa is the emission wavelength, and the ordinate is the fluorescence intensity);

[0057] (14) Fig.14This is the anti-interference experimental diagram of compound DPP-2 detecting hydrazine hydrate;

[0058] (15) Fig.15 It is a high-resolution mass spectrum of compound DPP-2 after adding hydrazine hydrate. DETAILED DESCRIPTION

[0059] In order to better understand the technical solution of the present invention, it is further described in detail below through specific embodiments.

[0060] Example 1

[0061] Weigh 1.31 g of 4-cyanobenzaldehyde, 0.097 g of aminosulfonic acid, and 4.96 g of ethylene glycol and dissolve them in 60 ml of cyclohexane. After reflux reaction for 12 h, cool to room temperature, extract the reaction solution with dichloromethane, wash once with 100 ml of saturated sodium bicarbonate solution, and wash twice with 100 ml of water. After dehydrating the organic phase with anhydrous magnesium sulfate, filter and rotary evaporate to obtain a crude product. The crude product is recrystallized with ethanol, filtered, and dried to obtain 1.63 g of compound 1, with a yield of 93%;

[0062] Weigh 1.92 g of ethyl benzoylacetate, 1.22 g of ethyl chloroacetate, 2.07 g of anhydrous potassium carbonate, and 0.60 g of sodium iodide, add them to a mixed solvent consisting of 20 ml of ethylene glycol dimethyl ether and 40 ml of acetone, heat to 65 ° C, react for 12 hours, cool to room temperature, filter, extract the filtrate with dichloromethane, wash with water three times, remove water from the organic phase with anhydrous magnesium sulfate, filter, rotary evaporate, and dry to obtain compound 2;

[0063] Weigh 15 g of ammonium acetate, add it to 50 ml of glacial acetic acid under nitrogen, heat to 65°C, stir until completely dissolved, add compound 2 obtained in step 2), react for 24 hours, cool to room temperature, pour the reaction solution into ice water, let stand for 15 minutes, filter, wash with water 3 times, recrystallize with ethanol, filter, and dry to obtain 1.50 g of compound 3, yield: 65% (relative to ethyl benzoyl acetate);

[0064] Weigh 1 g of metallic sodium, add it to 50 ml of anhydrous tert-amyl alcohol under nitrogen atmosphere, heat to 105°C, react until sodium is completely dissolved, reduce the temperature to 60°C, add 1.05 g of compound 1 obtained in step 1) and 1.16 g of compound 3 obtained in step 3), heat to 95°C, react for 12 h, cool to room temperature, add 150 ml of methanol and 10 ml of acetic acid, stir at room temperature for 2 hours, filter, wash repeatedly with methanol and water until the filtrate is colorless, and dry to obtain 1.11 g of compound 4, yield: 62%;

[0065] Weigh 1.12g potassium tert-butoxide and 1.74g compound 4, add them to anhydrous N-methylpyrrolidone under nitrogen atmosphere, heat to 60°C, stir until the solution turns red, add 5.79g n-octane bromide, react for 24h, cool to room temperature, filter, wash the filter residue with dichloromethane, combine the filtrate and dichloromethane, wash 6 times with 100ml brine, wash 6 times with 100ml water, remove water from the organic phase with anhydrous magnesium sulfate, filter, rotary evaporate, separate by column chromatography, and dry to obtain 1.84g compound 5 with a yield of 63%;

[0066] 1.43 g of compound 5 obtained in step 5) was weighed and dissolved in 30 ml of tetrahydrofuran, 15 ml of 0.02 mol / L hydrochloric acid was added, and refluxed for 12 hours, then cooled to room temperature, the reaction solution was extracted with dichloromethane, washed with water 3 times, the organic layer was dehydrated with anhydrous magnesium sulfate, filtered, and rotary evaporated to obtain a crude product, which was recrystallized with ethanol, filtered, and dried to obtain 1.28 g of compound 6, yield: 95%;

[0067] Weigh 0.171 g of ethanethiol, 0.39 g of boron trifluoride etherate, and 0.675 g of compound 6 obtained in step 6), add them to anhydrous dichloromethane under nitrogen protection, react at 0°C for 8 h, warm to room temperature, and rotary evaporate the reaction solution to obtain a crude product, separate by column chromatography, and dry to obtain 0.73 g of compound HG1, with a yield of 90%;

[0068] Weigh 0.162 g of diaminomaleonitrile and 0.675 g of compound 6 obtained in step 6), add them to anhydrous ethanol, reflux for 10 h, cool to room temperature, put in a refrigerator to crystallize overnight, filter, wash with cold ethanol, and dry to obtain 0.748 g of compound DPP-1, yield: 95%;

[0069] Weigh 0.099 g of malononitrile and 0.675 g of compound 6 obtained in step 6), add them to anhydrous ethanol, reflux for 12 h, cool to room temperature, place in a refrigerator for crystallization overnight, filter, wash with cold ethanol, and dry to obtain 0.691 g of compound DPP-2, with a yield of 94%.

[0070] Example 2

[0071] Weigh 1.31 g of 4-cyanobenzaldehyde, 0.097 g of aminosulfonic acid, and 4.96 g of ethylene glycol and dissolve them in 60 ml of cyclohexane. After reflux reaction for 10 h, cool to room temperature, extract the reaction solution with dichloromethane, wash once with 100 ml of saturated sodium bicarbonate solution, and wash twice with 100 ml of water. After the organic phase is dehydrated with anhydrous magnesium sulfate, it is filtered and rotary evaporated to obtain a crude product. The crude product is recrystallized with ethanol, filtered, and dried to obtain 1.56 g of compound 1, with a yield of 89%;

[0072] Weigh 1.92 g of ethyl benzoylacetate, 1.22 g of ethyl chloroacetate, 2.07 g of anhydrous potassium carbonate, and 0.60 g of sodium iodide, add them to a mixed solvent consisting of 20 ml of ethylene glycol dimethyl ether and 40 ml of acetone, heat to 65 ° C, react for 12 hours, cool to room temperature, filter, extract the filtrate with dichloromethane, wash with water three times, remove water from the organic phase with anhydrous magnesium sulfate, filter, rotary evaporate, and dry to obtain compound 2;

[0073] Weigh 15 g of ammonium acetate, add it to 50 ml of glacial acetic acid under nitrogen, heat to 75°C, stir until completely dissolved, add compound 2 obtained in step 2), react for 20 hours, cool to room temperature, pour the reaction solution into ice water, let stand for 15 minutes, filter, wash with water 3 times, recrystallize with ethanol, filter, and dry to obtain 1.386 g of compound 3, yield: 60% (relative to ethyl benzoyl acetate);

[0074] Weigh 1 g of metallic sodium, add it to 50 ml of anhydrous tert-amyl alcohol under nitrogen atmosphere, heat to 105°C, react until sodium is completely dissolved, reduce the temperature to 60°C, add 1.05 g of compound 1 obtained in step 1) and 1.16 g of compound 3 obtained in step 3), heat to 95°C, react for 10 h, cool to room temperature, add 150 ml of methanol and 10 ml of acetic acid, stir at room temperature for 2 hours, filter, wash repeatedly with methanol and water until the filtrate is colorless, and dry to obtain 1.04 g of compound 4, yield: 58%;

[0075] Weigh 1.12g potassium tert-butoxide and 1.74g compound 4, add them to anhydrous N-methylpyrrolidone under nitrogen atmosphere, heat to 65°C, stir until the solution turns red, add 5.79g n-octane bromide, react for 20h, cool to room temperature, filter, wash the residue with dichloromethane, combine the filtrate and dichloromethane, wash 6 times with 100ml concentrated brine, wash 6 times with 100ml water, remove water from the organic phase with anhydrous magnesium sulfate, filter, rotary evaporate, separate by column chromatography, and dry to obtain 1.63g compound 5 with a yield of 56%;

[0076] 1.43 g of compound 5 obtained in step 5) was weighed and dissolved in 30 ml of tetrahydrofuran, 10 ml of 0.02 mol / L hydrochloric acid was added, and refluxed for 12 hours, then cooled to room temperature, the reaction solution was extracted with dichloromethane, washed with water 3 times, the organic layer was dehydrated with anhydrous magnesium sulfate, filtered, and rotary evaporated to obtain a crude product, which was recrystallized with ethanol, filtered, and dried to obtain 1.18 g of compound 6, yield: 88%;

[0077] Weigh 0.171 g of ethanethiol, 0.39 g of boron trifluoride etherate, and 0.675 g of compound 6 obtained in step 6), add them to anhydrous dichloromethane under nitrogen protection, react at 0°C for 6 h, warm to room temperature, and rotary evaporate the reaction solution to obtain a crude product. Separate by column chromatography and dry to obtain 0.70 g of compound HG1, yield: 87%;

[0078] Weigh 0.162 g of diaminomaleonitrile and 0.675 g of compound 6 obtained in step 6), add them to anhydrous ethanol, reflux for 8 h, cool to room temperature, put in a refrigerator to crystallize overnight, filter, wash with cold ethanol, and dry to obtain 0.717 g of compound DPP-1, yield: 91%;

[0079] Weigh 0.099 g of malononitrile and 0.675 g of compound 6 obtained in step 6), add them to anhydrous ethanol, reflux for 10 h, cool to room temperature, put in a refrigerator for crystallization overnight, filter, wash with cold ethanol, and dry to obtain 0.662 g of compound DPP-2, with a yield of 90%.

[0080] Example 3

[0081] Weigh 1.31 g of 4-cyanobenzaldehyde, 0.078 g of aminosulfonic acid, and 4.96 g of ethylene glycol and dissolve them in 60 ml of cyclohexane. After reflux reaction for 12 h, cool to room temperature, extract the reaction solution with dichloromethane, wash once with 100 ml of saturated sodium bicarbonate solution, and wash twice with 100 ml of water. After the organic phase is dehydrated with anhydrous magnesium sulfate, it is filtered and rotary evaporated to obtain a crude product. The crude product is recrystallized with ethanol, filtered, and dried to obtain 1.54 g of compound 1, with a yield of 88%;

[0082] Weigh 1.92 g of ethyl benzoylacetate, 1.22 g of ethyl chloroacetate, 2.07 g of anhydrous potassium carbonate, and 0.60 g of sodium iodide, add them to a mixed solvent consisting of 20 ml of ethylene glycol dimethyl ether and 40 ml of acetone, heat to 65 ° C, react for 12 hours, cool to room temperature, filter, extract the filtrate with dichloromethane, wash with water three times, remove water from the organic phase with anhydrous magnesium sulfate, filter, rotary evaporate, and dry to obtain compound 2;

[0083] Weigh 10 g of ammonium acetate, add it to 50 ml of glacial acetic acid under nitrogen, heat to 65°C, stir until completely dissolved, add compound 2 obtained in step 2), react for 24 hours, cool to room temperature, pour the reaction solution into ice water, let stand for 15 minutes, filter, wash with water 3 times, recrystallize with ethanol, filter, and dry to obtain 1.04 g of compound 3, yield: 45% (relative to ethyl benzoyl acetate);

[0084] Weigh 1.5 g of metallic sodium, add it to 50 ml of anhydrous tert-amyl alcohol under nitrogen atmosphere, heat to 105° C., react until sodium is completely dissolved, reduce the temperature to 60° C., add 1.05 g of compound 1 obtained in step 1) and 1.16 g of compound 3 obtained in step 3), heat to 95° C., react for 12 h, cool to room temperature, add 150 ml of methanol and 10 ml of acetic acid, stir at room temperature for 2 hours, filter, wash repeatedly with methanol and water until the filtrate is colorless, and dry to obtain 0.92 g of compound 4, yield: 51%;

[0085] Weigh 1.12g potassium tert-butoxide and 1.74g compound 4, add them to anhydrous N-methylpyrrolidone under nitrogen atmosphere, heat to 60°C, stir until the solution turns red, add 4.82g n-octane bromide, react for 24h, cool to room temperature, filter, wash the residue with dichloromethane, combine the filtrate and dichloromethane, wash 6 times with 100ml concentrated brine, wash 6 times with 100ml water, remove water from the organic phase with anhydrous magnesium sulfate, filter, rotary evaporate, separate by column chromatography, and dry to obtain 1.75g ​​compound 5 with a yield of 60%;

[0086] 1.43 g of compound 5 obtained in step 5) was weighed and dissolved in 30 ml of tetrahydrofuran, 10 ml of 0.02 mol / L hydrochloric acid was added, and refluxed for 12 hours, then cooled to room temperature, the reaction solution was extracted with dichloromethane, washed with water three times, the organic layer was dehydrated with anhydrous magnesium sulfate, filtered, and rotary evaporated to obtain a crude product, which was recrystallized with ethanol, filtered, and dried to obtain 1.22 g of compound 6, yield: 90%;

[0087] Weigh 0.155 g of ethanethiol, 0.39 g of boron trifluoride etherate, and 0.675 g of compound 6 obtained in step 6), add them to anhydrous dichloromethane under nitrogen protection, react at 0°C for 8 h, warm to room temperature, and rotary evaporate the reaction solution to obtain a crude product. Separate by column chromatography and dry to obtain 0.65 g of compound HG1, yield: 81%;

[0088] Weigh 0.135 g of diaminomaleonitrile and 0.675 g of compound 6 obtained in step 6), add them to anhydrous ethanol, reflux for 10 h, cool to room temperature, put in a refrigerator to crystallize overnight, filter, wash with cold ethanol, and dry to obtain 0.701 g of compound DPP-1, yield: 89%;

[0089] Weigh 0.082 g of malononitrile and 0.675 g of compound 6 obtained in step 6), add them to anhydrous ethanol, reflux for 12 h, cool to room temperature, place in a refrigerator for crystallization overnight, filter, wash with cold ethanol, and dry to obtain 0.647 g of compound DPP-2, with a yield of 88%.

[0090] Example 4

[0091] Weigh 1.31 g of 4-cyanobenzaldehyde, 0.097 g of aminosulfonic acid, and 3.10 g of ethylene glycol and dissolve them in 60 ml of cyclohexane. After reflux reaction for 12 h, cool to room temperature, extract the reaction solution with dichloromethane, wash once with 100 ml of saturated sodium bicarbonate solution, and wash twice with 100 ml of water. After the organic phase is dehydrated with anhydrous magnesium sulfate, it is filtered and rotary evaporated to obtain a crude product. The crude product is recrystallized with ethanol, filtered, and dried to obtain 1.47 g of compound 1, with a yield of 84%;

[0092] Weigh 1.92 g of ethyl benzoylacetate, 1.22 g of ethyl chloroacetate, 1.38 g of anhydrous potassium carbonate, and 0.60 g of sodium iodide, add them to a mixed solvent consisting of 20 ml of ethylene glycol dimethyl ether and 40 ml of acetone, heat to 65 ° C, react for 12 hours, cool to room temperature, filter, extract the filtrate with dichloromethane, wash with water three times, remove water from the organic phase with anhydrous magnesium sulfate, filter, rotary evaporate, and dry to obtain compound 2;

[0093] Weigh 15 g of ammonium acetate, add it to 50 ml of glacial acetic acid under nitrogen, heat to 65°C, stir until completely dissolved, add compound 2 obtained in step 2), react for 24 hours, cool to room temperature, pour the reaction solution into ice water, let stand for 15 minutes, filter, wash with water 3 times, recrystallize with ethanol, filter, and dry to obtain 1.32 g of compound 3, yield: 57% (relative to ethyl benzoyl acetate);

[0094] Weigh 1 g of metallic sodium, add it to 50 ml of anhydrous tert-amyl alcohol under nitrogen atmosphere, heat to 105°C, react until sodium is completely dissolved, reduce the temperature to 60°C, add 1.31 g of compound 1 obtained in step 1) and 1.16 g of compound 3 obtained in step 3), heat to 95°C, react for 12 h, cool to room temperature, add 150 ml of methanol and 10 ml of acetic acid, stir at room temperature for 2 hours, filter, wash repeatedly with methanol and water until the filtrate is colorless, and dry to obtain 1.08 g of compound 4, yield: 60%;

[0095] Weigh 1.12g potassium tert-butoxide and 1.74g compound 4, add them to anhydrous N-methylpyrrolidone under nitrogen atmosphere, heat to 60°C, stir until the solution turns red, add 7.72g n-octane bromide, react for 24h, cool to room temperature, filter, wash the residue with dichloromethane, combine the filtrate and dichloromethane, wash 6 times with 100ml concentrated brine, wash 6 times with 100ml water, remove water from the organic phase with anhydrous magnesium sulfate, filter, rotary evaporate, separate by column chromatography, and dry to obtain 1.81g compound 5 with a yield of 62%;

[0096] 1.43 g of compound 5 obtained in step 5) was weighed and dissolved in 30 ml of tetrahydrofuran, 15 ml of 0.02 mol / L hydrochloric acid was added, and refluxed for 12 hours, then cooled to room temperature, the reaction solution was extracted with dichloromethane, washed with water 3 times, the organic layer was dehydrated with anhydrous magnesium sulfate, filtered, and rotary evaporated to obtain a crude product, which was recrystallized with ethanol, filtered, and dried to obtain 1.28 g of compound 6, yield: 95%;

[0097] Weigh 0.171 g of ethanethiol, 0.53 g of boron trifluoride etherate, and 0.675 g of compound 6 obtained in step 6), add them to anhydrous dichloromethane under nitrogen protection, react at 0°C for 8 h, warm to room temperature, and rotary evaporate the reaction solution to obtain a crude product, separate by column chromatography, and dry to obtain 0.73 g of compound HG1, with a yield of 90%;

[0098] Weigh 0.202 g of diaminomaleonitrile and 0.675 g of compound 6 obtained in step 6), add them to anhydrous ethanol, reflux for 8 h, cool to room temperature, put in a refrigerator to crystallize overnight, filter, wash with cold ethanol, and dry to obtain 0.740 g of compound DPP-1, yield: 94%;

[0099] Weigh 0.165 g of malononitrile and 0.675 g of compound 6 obtained in step 6), add them to anhydrous ethanol, reflux for 10 h, cool to room temperature, put in a refrigerator for crystallization overnight, filter, wash with cold ethanol, and dry to obtain 0.676 g of compound DPP-2, with a yield of 92%.

[0100] Example 5

[0101] Weigh 1.31 g of 4-cyanobenzaldehyde, 0.078 g of aminosulfonic acid, and 3.10 g of ethylene glycol and dissolve them in 60 ml of cyclohexane. After reflux reaction for 12 h, cool to room temperature, extract the reaction solution with dichloromethane, wash once with 100 ml of saturated sodium bicarbonate solution, and wash twice with 100 ml of water. After dehydrating the organic phase with anhydrous magnesium sulfate, filter and rotary evaporate to obtain a crude product. The crude product is recrystallized with ethanol, filtered, and dried to obtain 1.38 g of compound 1, with a yield of 79%;

[0102] Weigh 1.92 g of ethyl benzoylacetate, 1.22 g of ethyl chloroacetate, 2.07 g of anhydrous potassium carbonate, and 0.30 g of sodium iodide, add them to a mixed solvent consisting of 20 ml of ethylene glycol dimethyl ether and 40 ml of acetone, heat to 65 ° C, react for 12 hours, cool to room temperature, filter, extract the filtrate with dichloromethane, wash with water three times, remove water from the organic phase with anhydrous magnesium sulfate, filter, rotary evaporate, and dry to obtain compound 2;

[0103] Weigh 15 g of ammonium acetate, add it to 50 ml of glacial acetic acid under nitrogen, heat to 65°C, stir until completely dissolved, add compound 2 obtained in step 2), react for 24 hours, cool to room temperature, pour the reaction solution into ice water, let stand for 15 minutes, filter, wash with water 3 times, recrystallize with ethanol, filter, and dry to obtain 1.39 g of compound 3, yield: 60% (relative to ethyl benzoyl acetate);

[0104] Weigh 1 g of metallic sodium, add it to 50 ml of anhydrous tert-amyl alcohol under nitrogen atmosphere, heat to 105°C, react until sodium is completely dissolved, reduce the temperature to 60°C, add 1.05 g of compound 1 obtained in step 1) and 1.16 g of compound 3 obtained in step 3), heat to 95°C, react for 12 h, cool to room temperature, add 150 ml of methanol and 15 ml of acetic acid, stir at room temperature for 2 hours, filter, wash repeatedly with methanol and water until the filtrate is colorless, and dry to obtain 1.11 g of compound 4, yield: 62%;

[0105] Weigh 1.12g potassium tert-butoxide and 1.74g compound 4, add them to anhydrous N-methylpyrrolidone under nitrogen atmosphere, heat to 60°C, stir until the solution turns red, add 5.79g n-octane bromide, react for 24h, cool to room temperature, filter, wash the filter residue with dichloromethane, combine the filtrate and dichloromethane, wash 6 times with 100ml brine, wash 6 times with 100ml water, remove water from the organic phase with anhydrous magnesium sulfate, filter, rotary evaporate, separate by column chromatography, and dry to obtain 1.84g compound 5 with a yield of 63%;

[0106] 1.43 g of compound 5 obtained in step 5) was weighed and dissolved in 30 ml of tetrahydrofuran, 15 ml of 0.02 mol / L hydrochloric acid was added, and refluxed for 12 hours, then cooled to room temperature, the reaction solution was extracted with dichloromethane, washed with water 3 times, the organic layer was dehydrated with anhydrous magnesium sulfate, filtered, and rotary evaporated to obtain a crude product, which was recrystallized with ethanol, filtered, and dried to obtain 1.28 g of compound 6, yield: 95%;

[0107] Weigh 0.155 g of ethanethiol, 0.26 g of boron trifluoride etherate, and 0.675 g of compound 6 obtained in step 6), add them to anhydrous dichloromethane under nitrogen protection, react at 0°C for 8 h, warm to room temperature, and rotary evaporate the reaction solution to obtain a crude product. Separate by column chromatography and dry to obtain 0.65 g of compound HG1, yield: 81%;

[0108] Weigh 0.27 g of diaminomaleonitrile and 0.675 g of compound 6 obtained in step 6), add them to anhydrous ethanol, reflux for 10 h, cool to room temperature, put in a refrigerator to crystallize overnight, filter, wash with cold ethanol, and dry to obtain 0.740 g of compound DPP-1, yield: 94%;

[0109] Weigh 0.165 g of malononitrile and 0.675 g of compound 6 obtained in step 6), add them to anhydrous ethanol, reflux for 12 h, cool to room temperature, place in a refrigerator for crystallization overnight, filter, wash with cold ethanol, and dry to obtain 0.691 g of compound DPP-2, with a yield of 94%.

[0110] HG1 compound HNMR spectrum (attached Figure 1 ) and mass spectrometry analysis (attached Figure 2 ):

[0111] Table 1 was obtained by analyzing the structural formula and nuclear magnetic resonance hydrogen spectrum of compound HG1. This compound has 15 kinds of hydrogen. The signal peak near 0.79ppm is the signal peak of proton 1, and its peak area is 6.00; the signal peaks in the range of 1.07-1.21ppm are the signal peaks of protons 2, 3, 4, 5, 6 and 15, and its peak area is 26.15; the signal peak near 1.36ppm is the signal peak of proton 7, and its peak area is 4.05; the signal peak near 3.67ppm is the signal peak of proton 8, and its peak area is 4.07; the signal peak near 7.56ppm is the signal peak of proton 8, and its peak area is 4.07; The peak is the signal peak of proton 9, and its peak area is 2.99; the signal peak near 7.62ppm is the signal peak of proton 10, and its peak area is 2.101; the signal peak near 7.81ppm is the signal peak of protons 11 and 12, and its peak area is 4.05; the signal peak near 5.28ppm is the signal peak of proton 13, and its peak area is 1.00; the signal peak near 2.50-2.65ppm is the signal peak of proton 14, and its peak area is 4.05. It can be seen that the nuclear magnetic resonance hydrogen spectrum of the compound is in good agreement with the structure of the compound.

[0112] Compound Structure C 39 H 54 N2O2S2, calculated molecular weight is 646.3627, tested molecular weight is 647.3693 (C 39 H 54 N2O2S2) + . It can be concluded that the mass spectrum of the compound is consistent with the expected molecular weight.

[0113] Table 1 Compound HQ1 1 Chemical shifts and peak assignments of HNMR.

[0114] Table 1

[0115]

[0116] DPP-1 compound H NMR spectrum (attached Figure 5 ) and mass spectrometry analysis (attached Figure 6 ):

[0117] Table 2 was obtained by analyzing the structural formula and nuclear magnetic resonance hydrogen spectrum of compound DPP-1. This compound has 14 kinds of hydrogen. Among them, the signal peak appearing near 0.80ppm is the signal peak of proton 1, and its peak area is 6.27; the signal peak appearing in the range of 1.08-1.21ppm is the signal peak of proton 2, 3, 4, 5 and 6, and its peak area is 20.40; the signal peak appearing near 1.38ppm is the signal peak of proton 7, and its peak area is 4.09; the signal peak appearing near 3.72ppm is the signal peak of proton 8, and its peak area is 4.06; the signal peak appearing near 7.59ppm is the signal peak of proton 9, and its peak area is is 3.07; the signal peak near 7.82ppm is the signal peak of proton 10, and its peak area is 2.10; the signal peak near 7.92ppm is the signal peak of proton 11, and its peak area is 2.05; the signal peak near 8.23ppm is the signal peak of proton 12, and its peak area is 1.92; the signal peak near 8.34ppm is the signal peak of proton 13, and its peak area is 1.00; the signal peak near 8.17ppm is the signal peak of proton 14, and its peak area is 1.90. It can be seen that the nuclear magnetic resonance hydrogen spectrum of the compound is in good agreement with the structure of the compound.

[0118] Compound Structure C 39 H 46 N6O2, calculated molecular weight is 630.3682, tested molecular weight is 631.3747 (C 39 H 46 N6O2) + . It can be concluded that the mass spectrum of the compound is consistent with the expected molecular weight.

[0119] Table 2 Compound DPP-1 1 Chemical shifts and peak assignments of HNMR.

[0120] Table 2

[0121]

[0122] DPP-2 compound H NMR spectrum (attached Fig. 9 ) and mass spectrometry analysis (attached Fig.10 ):

[0123] Table 3 was obtained by analyzing the structural formula and nuclear magnetic resonance hydrogen spectrum of compound DPP-2. This compound has 13 kinds of hydrogen. The signal peak appearing near 0.81ppm is the signal peak of proton 1, and its peak area is 6.08; the signal peak appearing in the range of 1.09-1.23ppm is the signal peak of proton 2, 3, 4, 5 and 6, and its peak area is 20.27; the signal peak appearing near 1.39ppm is the signal peak of proton 7, and its peak area is 4.04; the signal peak appearing near 3.73ppm is the signal peak of proton 8, and its peak area is 4.09; the signal peak appearing near 7.60ppm is the signal peak of proton 8, and its peak area is 4.09; The signal peak at 7.83ppm is the signal peak of proton 10, and its peak area is 2.05; the signal peak at 8.06ppm is the signal peak of proton 11, and its peak area is 2.01; the signal peak at 8.12ppm is the signal peak of proton 12, and its peak area is 2.03; the signal peak at 8.64ppm is the signal peak of proton 13, and its peak area is 1.00. It can be seen that the hydrogen nuclear magnetic resonance spectrum of the compound is in good agreement with the structure of the compound.

[0124] Compound Structure C 38 H 44 N4O2, calculated molecular weight is 588.3464, tested molecular weight is 589.3535 (C 38 H 44 N4O2) + . It can be concluded that the mass spectrum of the compound is consistent with the expected molecular weight.

[0125] Table 3 Compound DPP-2 1 Chemical shifts and peak assignments of HNMR.

[0126] Table 3

[0127]

[0128] Compound HG1 prepared in Example 1 was dissolved and diluted in tetrahydrofuran: water (1 / 1, v / v) to prepare 1.0×10 -5 mol / L sample solution. The fluorescence excitation wavelength of the compound was determined using an F-700 fluorescence spectrophotometer, and the fluorescence spectrum of the compound was measured. Equivalent amounts of different metal ions Hg 2+ 、Ag + , Ba + 、Cd + 、Co + , Cu 2+ , Fe 2+ , Fe 3+ , K+ 、Na + 、Ni 2+ , Pb 2+ , Sr 2+ 、Zn 2+ Determine the fluorescence emission spectrum of the fluorescent probe in the presence of various metal ions (such as the attached Figure 3 As shown), the probe emits yellow fluorescence, and Hg 2+ After that, the fluorescence quickly turned orange and the fluorescence intensity weakened. However, the fluorescence intensity did not change much after adding other ions, and no fluorescence red shift occurred. This result shows that the probe HG1 can effectively inhibit Hg 2+ It has a good identification function.

[0129] The compound DPP-1 prepared in Example 1 was dissolved and diluted in tetrahydrofuran: water (1 / 1, v / v) to prepare 1.0X 10 -5 mol / L sample solution. The fluorescence excitation wavelength of the compound was determined using an F-700 fluorescence spectrophotometer, and the fluorescence spectrum of the compound was measured. Equivalent amounts of different ions ClO were added to the solution. - 、F - Br - , Cl - 、NO3 - 、HSO3 - 、ACO - 、HCO3 - 、CO3 2- , S 2- 、SO4 2- , GSH, Cys and H2O2 were measured in the presence of each ion. The fluorescence emission spectra of the fluorescent probes (such as the attached Figure 7 As shown), the probe emits red fluorescence, and ClO - After that, the fluorescence quickly turned orange and the fluorescence intensity became stronger. However, the fluorescence intensity did not change much after adding other ions, and no fluorescence blue shift occurred. This result shows that the probe DPP-1 can effectively inhibit ClO - It has a good identification function.

[0130] The compound DPP-2 prepared in Example 1 was dissolved and diluted with ethanol: water (2 / 1, v / v) to prepare 1.0×10 -5 mol / L sample solution. The fluorescence excitation wavelength of the compound was measured using an F-700 fluorescence spectrophotometer, and the fluorescence spectrum of the compound was measured. Equivalent amounts of N2H4, Mg 2+ , Cu 2+ , Fe 2+ , Fe 3+ 、Al 3+ , Ca 2+ , Ba 2+Cr 3+ , ClO - 、F - Br - , Cl - 、NO3 - 、HSO3 - 、ACO - 、HCO3 - 、CO3 2- , S 2- 、SO4 2- , GSH, Cys and H2O2 were measured in the presence of each ion. The fluorescence emission spectra of the fluorescent probes (such as the attached Fig.11 As shown in the figure, the probe emits red fluorescence. After adding hydrazine hydrate, the fluorescence quickly turns to yellow and the fluorescence intensity becomes stronger. However, when other ions are added, the fluorescence intensity does not change much and no fluorescence blue shift occurs. This result shows that the probe DPP-2 has a good recognition effect on hydrazine hydrate.

[0131] In the presence of other ions, the fluorescent probe HG1 selectively recognizes mercury ions, i.e., ion competition experiments (see attached Figure 4 The compound HG1 prepared in Example 1 was dissolved and diluted with tetrahydrofuran: water (1 / 1, v / v) to prepare 1.0X 10 -5 mol / L sample solution. Equivalent amounts of different ions (Ag + , Ba + 、Cd + 、Co + , Cu 2 + , Fe 2+ , Fe 3+ , K + 、Na + 、Ni 2+ , Pb 2+ , Sr 2+ 、Zn 2+ ), the fluorescence intensity of probe HG1 did not change significantly, while the addition of an equivalent amount of Hg 2+ After that, the fluorescence intensity increased significantly, which proved that the probe HG1 can still detect Hg even in the presence of other ions. 2+ Has higher selectivity.

[0132] In the presence of other ions, the fluorescent probe DPP-1 selectively recognizes hypochlorite ions, i.e., ion competition experiments (see attached Figure 8 The compound DPP-1 prepared in Example 1 was dissolved and diluted in tetrahydrofuran: water (1 / 1, v / v) to prepare 1.0X 10 -5mol / L sample solution. Equivalent amounts of different ions (F - Br - , Cl - 、NO3 - 、HSO3 - 、ACO - 、HCO3 - 、CO3 2- , S 2- 、SO4 2- , GSH, Cys, H2O2), the fluorescence intensity of the probe DPP-1 did not change significantly, while the addition of an equivalent amount of ClO - After that, the fluorescence intensity increased significantly, which proved that the probe HG1 can still detect ClO even in the presence of other ions. - Has higher selectivity.

[0133] In the presence of other ions, the fluorescent probe DPP-2 selectively recognizes mercury ions, i.e., ion competition experiments (see attached Fig.12 The compound DPP-2 prepared in Example 1 was dissolved and diluted with ethanol: water (2 / 1, v / v) to prepare 1.0× 10 -5 mol / L sample solution. Equivalent amounts of different ions (Mg 2+ , Cu 2+ , Fe 2+ , Fe 3 + 、Al 3+ , Ca 2+ , Ba 2+ Cr 3+ , ClO - 、F - Br - , Cl - 、NO3 - 、HSO3 - 、ACO - 、HCO3 - 、CO3 2- , S 2- 、SO4 2- , GSH, Cys, H2O2), the fluorescence intensity of probe DPP-2 did not change significantly, while after adding an equivalent amount of N2H4, the fluorescence intensity was significantly enhanced, which proves that probe HG1 still has a high selectivity for N2H4 even in the presence of other ions.

[0134] The probe HG1 was compared with Hg 2+ 1HNMR spectra before and after the reaction (see attached Figure 5 Probe HG1 and Hg2+ After the reaction, the signal peaks attributed to hydrogen 13 and hydrogen 14 disappeared, and new peaks attributed to aldehyde hydrogen were observed. 2+ The H NMR spectrum after the reaction is consistent with that of compound 6. The results show that 2+ Under the promotion of , the thioacetal group is eliminated to produce the corresponding aldehyde group.

[0135] The probe DPP-1 and ClO were compared. - Before and after reaction 1 HNMR spectrum (see attached Fig.10 Probe DPP-1 and ClO - After the reaction, the signal peaks attributed to hydrogen 13 and hydrogen 14 disappeared, and new peaks attributed to aldehyde hydrogen were observed. - The H NMR spectrum after the reaction is consistent with that of compound 6. The results show that in ClO - Under the promotion of , the maleonitrile part of the probe DPP-1 was eliminated, thereby generating the corresponding aldehyde group.

[0136] The reaction mixture of probe DPP-2 and excess hydrazine hydrate was detected by high-resolution mass spectrometry (see attached Fig.15 As shown in Figure 2, the molecular ion peak of probe DPP-2 disappears, and a new molecular ion peak appears at m / z = 555.3691. This peak can be attributed to the hydrazone generated by the reaction, corresponding to the structure C of the hydrazone. 35 H 46 N4O2, its molecular weight is calculated to be 554.3621.

Claims

1. A fluorescent probe based on 2,5-dioctyl-3,6-diphenylpyrrolopyrrole dione, characterized in that its specific structure is as follows:

2. The fluorescent probe based on 2,5-dioctyl-3,6-diphenylpyrrolopyrrole diketo as claimed in claim 1, characterized in that The synthetic route is as follows:

3. Prepare the fluorescent probe based on 2,5-dioctyl-3,6-diphenylpyrrolopyrrole diketo as claimed in claim 1, characterized in that: The preparation method is as follows: 1) Weigh metallic sodium, add it to anhydrous tert-amyl alcohol under nitrogen atmosphere, heat to 95-105°C, react until sodium is completely dissolved, reduce the temperature to 50-60°C, add compound 1 and compound 3, heat to 95-105°C, react for 10-14 hours, cool to room temperature, add methanol and acetic acid, stir at room temperature for 1-2 hours, filter, wash repeatedly with methanol and water until the filtrate is colorless, and dry to obtain compound 4; 2) Weigh potassium tert-butoxide and compound 4 obtained in step 1), add them to anhydrous N-methylpyrrolidone under nitrogen atmosphere, heat to 55-65° C., stir until the solution turns red, add n-octane bromide, react for 20-24 hours, cool to room temperature, filter with suction, wash the filter residue with dichloromethane, combine the filtrate and dichloromethane, wash with concentrated brine and water, remove water from the organic phase with anhydrous magnesium sulfate, filter with suction, rotary evaporate, separate by column chromatography, and dry to obtain compound 5; 3) Weigh the compound 5 obtained in step 2) and dissolve it in 30 ml of tetrahydrofuran, add 0.02 mol / L hydrochloric acid, reflux for 10-12 hours, cool to room temperature, extract the reaction solution with dichloromethane, wash with water three times, remove water from the organic layer with anhydrous magnesium sulfate, filter, and rotary evaporate to obtain a crude product, which is recrystallized with ethanol, filtered, and dried to obtain compound 6; 4) Weigh ethanethiol, boron trifluoride etherate and compound 6 obtained in step 3), add them into anhydrous dichloromethane under nitrogen protection, react at 0° C. for 6-8 hours, warm to room temperature, and rotary evaporate the reaction solution to obtain a crude product, separate by column chromatography, and dry to obtain compound HG1; 5) Weigh diaminomaleonitrile and compound 6 obtained in step 3) and dissolve them in anhydrous ethanol. After reflux reaction for 8-10 hours, cool to room temperature, place in a refrigerator for crystallization overnight, filter, wash with cold ethanol, and dry to obtain compound DPP-1; 6) Weigh malononitrile and compound 6 obtained in step 3) and dissolve them in anhydrous ethanol. After reflux reaction for 10-12 hours, cool to room temperature, place in a refrigerator for crystallization overnight, filter, wash with cold ethanol, and dry to obtain compound DPP-2.

4. The method for preparing a fluorescent probe based on 2,5-dioctyl-3,6-diphenylpyrrolopyrrole diketo as claimed in claim 3, characterized in that: In step 1), 0.2-0.3 g of metallic sodium is added to every 10 ml of anhydrous tert-amyl alcohol; the molar ratio of compound 3 to metallic sodium is 1:6-1:10; the molar ratio of compound 3 to compound 1 is 1:1-1:1.5; and the volume ratio of acetic acid to methanol is 1:15-1:

20.

5. The method for preparing a fluorescent probe based on 2,5-dioctyl-3,6-diphenylpyrrolopyrrole diketo as claimed in claim 3, characterized in that: In step 2), the molar ratio of compound 4 to potassium tert-butoxide is 1:2 to 1:3; the molar ratio of compound 4 to n-octane bromide is 1:5 to 1:8; the concentrated brine is prepared by adding 1 to 2 g of sodium chloride per 10 ml of water, the organic phase is first washed with concentrated brine for 4 to 6 times, and then washed with pure water for 4 to 6 times; in column chromatography separation, n-octane bromide is first washed away with a large amount of petroleum ether, and then eluted with ethyl acetate and petroleum ether, and the volume ratio of ethyl acetate to petroleum ether is 3:

10.

6. The method for preparing a fluorescent probe based on 2,5-dioctyl-3,6-diphenylpyrrolopyrrole diketo as claimed in claim 3, characterized in that: In step 3), the volume ratio of 0.02 mol / L hydrochloric acid to tetrahydrofuran is 1:2 to 1:

3.

7. The method for preparing a fluorescent probe based on 2,5-dioctyl-3,6-diphenylpyrrolopyrrole diketo as claimed in claim 3, characterized in that: In step 4), the molar ratio of compound 6 to ethyl mercaptan is 1:2 to 1:2.5; the molar ratio of boron trifluoride ether to ethyl mercaptan is 1:1 to 1:2; and the column chromatography is eluted with ethyl acetate and petroleum ether, and the volume ratio of ethyl acetate to petroleum ether is 3:

10.

8. The method for preparing a fluorescent probe based on 2,5-dioctyl-3,6-diphenylpyrrolopyrrole diketo as claimed in claim 3, characterized in that: In step 5), the molar ratio of compound 6 to diaminomaleonitrile is 1:1 to 1:

2.

9. The method for preparing a fluorescent probe based on 2,5-dioctyl-3,6-diphenylpyrrolopyrrole diketo as claimed in claim 3, characterized in that: In step 6), the molar ratio of compound 6 to malononitrile is 1:1 to 1:

2.

10. Use of the fluorescent probe based on 2,5-dioctyl-3,6-diphenylpyrrolopyrrole diketo as claimed in claim 1 in the preparation of mercury ion fluorescent probe, hypochlorite ion fluorescent probe and hydrazine hydrate fluorescent probe.

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