An aie-type cationic conjugated polymer, preparation method and application

Abstract

The application provides an AIE type cationic conjugated polymer, a preparation method and application, the AIE type cationic conjugated polymer is FTD-C8-MI, has typical aggregation-induced emission (AIE) characteristics and fluorescence resonance energy transfer (FRET), the structural formula of FTD-C8-MI contains polyfluorene fluorophore, triphenylamine (TPA) fluorophore and two long carbon chain-containing dithiophene benzothiadiazole (DBT) fluorophore, FTD-C8-MI shows cyan green fluorescence under the irradiation of 365 nm violet light; FTD-C8-MI can be dissolved in dimethyl sulfoxide, and when a small amount is dissolved in water, it presents red clear and transparent liquid; when dimethyl sulfoxide solution containing FTD-C8-MI is added to an aqueous solution containing PFAS, the emission color of FTD-C8-MI changes from cyan green to red; therefore, the fluorescence intensity change and the chroma change of color of FTD-C8-MI to PFAS can be used to establish quantitative detection of PFOA and PFOS (two common PFAS), so that high-sensitivity and high-selectivity quantitative detection of different types of PFAS in water medium can be realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fluorescent probe, in particular to an AIE type cationic conjugated polymer, a preparation method and application thereof. BACKGROUND

[0002] PFAS is a series of non-natural synthetic organic compounds containing fluorine elements, which has high thermal stability, hydrophobic and oleophobic properties, and chemical stability, and is widely used in textiles, cosmetics, food packaging, coatings and medical fields. However, due to its excellent stability, PFAS has become a kind of permanent organic pollutant, which can accumulate in the body through the food chain and cause health problems such as thyroid disease, endocrine disorder, immunotoxicity, and liver toxicity in human body. At present, PFAS has been detected in various water bodies around the world and seriously exceeded the standard, which poses a serious threat to the environment and human health.

[0003] The detection method of PFAS mainly uses liquid chromatography-mass spectrometry (LC-MS) combined technology, in addition to which there are methods such as Raman spectroscopy, gas chromatography-mass spectrometry (GC-MS), electrochemical sensor, and engineering bacteria for detection. Although these detection methods have the advantages of high accuracy, high sensitivity, and high specificity, they have the problems of complex analysis process, long analysis time, high cost, and easy interference, which are not suitable for rapid detection of large quantities of samples and real-time monitoring of different water bodies.

[0004] Compared with these methods, the fluorescence detection method has the characteristics of fast response speed, simple operation, and low cost, and has become the most suitable method for rapid evaluation of water quality safety. However, most of the fluorescence detection methods have low specificity and sensitivity that cannot meet the extremely low limit requirement of PFAS, and the development of a new fluorescence detection method for PFAS with ultra-sensitivity is still the main problem faced by researchers. SUMMARY

[0005] In view of the above problems existing in the prior art, the present application provides an AIE type cationic conjugated polymer, a preparation method and application thereof, so as to realize rapid, accurate and sensitive detection of PFAS. It is of great significance for timely early warning and prevention and control of water pollution and reducing the health risk of residents.

[0006] The specific application content is as follows:

[0007] In a first aspect, the present application provides an AIE type cationic conjugated polymer, which has the following structural formula:

[0008] .

[0009] In a second aspect, the present application provides a preparation method of the AIE type cationic conjugated polymer of the first aspect, which comprises the following steps:

[0010] Step 1, after mixing 2,7-dibromo-9,9-di(6-bromohexyl)fluorene, 4,7-bis(5- bromothiophene-2-yl)-5,6-bis(n-octyloxy)-2,1,3-benzothiadiazole and N-phenyl-4-(4,4,5,5- tetramethyl-1,3,2-dioxaborolan-2-yl)-N-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl) aniline, a dichloromethane solution is added to form a first solution;

[0011] Step 2, potassium carbonate is mixed with ultrapure water to form a second solution, the first solution is mixed with the second solution, and after adding an appropriate amount of palladium, it is transferred to a 50 ℃~130 ℃ reaction for 16 h~72 h, and the obtained product is purified by first separation to obtain a precursor polymer;

[0012] Step 3, after mixing the precursor polymer and 1-methylimidazole, it is transferred to a 40 ℃~120 ℃ reaction for 16 h~84 h, and the reaction product is purified by second separation to obtain an AIE type cation conjugated polymer FTD-C8-MI.

[0013] Optionally, in step 1, the amount ratio of 2,7-dibromo-9,9-di(6-bromohexyl)fluorene, 4,7-bis(5- bromothiophene-2-yl)-5,6-bis(n-octyloxy)-2,1,3-benzothiadiazole, N-phenyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-N-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl) aniline and dichloromethane solution is (0.02~4.0) g:(0.02~2.0) g:(0.02~5.0) g:(10~100) ml.

[0014] Optionally, in step 2, the amount ratio of potassium carbonate and ultrapure water is (0.5~6) g:(1~11) mL.

[0015] Optionally, in step 2, the amount of palladium is 0.01 g~0.20 g.

[0016] Optionally, in step 2, the first separation and purification includes:

[0017] The organic solvent in the obtained product is removed by a rotary evaporator, an appropriate amount of methanol is added for precipitation and centrifugation, and water and dichloromethane are added to the collected lower precipitate for organic phase extraction;

[0018] The obtained organic phase is dried with anhydrous sodium sulfate, and further rotary evaporation is performed to remove the organic solvent, and the purified precursor polymer is obtained.

[0019] Optionally, in step 3, the amount ratio of the precursor polymer and 1-methylimidazole is (20-100) mg:(1-10) mL.

[0020] Optionally, in step 3, the second separation and purification comprises:

[0021] An appropriate amount of methanol solution is added to the reaction product, and then transferred to a dialysis bag for dialysis for 1-3 days;

[0022] The dialysis solid is washed with chloroform for multiple times, and then collected by filtration, and further rotary evaporation is performed to remove the organic solvent, so as to obtain the AIE type cationic conjugated polymer FTD-C8-MI.

[0023] In a third aspect, the present application provides an application of the AIE type cationic conjugated polymer in the first aspect, and the AIE type cationic conjugated polymer is applied to a fluorescent probe.

[0024] Optionally, the AIE type cationic conjugated polymer is dissolved in dimethyl sulfoxide to construct a ratio type fluorescent probe for selective and quantitative detection of PFAS.

[0025] Compared with the prior art, the present application has the following advantages:

[0026] The AIE type cationic conjugated polymer provided by the present application is FTD-C8-MI, which has obvious aggregation-induced emission (AIE) characteristics and strong interchain fluorescence resonance energy transfer (interchain-FRET). FTD-C8-MI exhibits cyan green fluorescence under the irradiation of a 365 nm violet light lamp. FTD-C8-MI can be dissolved in dimethyl sulfoxide and a small amount of FTD-C8-MI dissolved in water appears as a red clear transparent liquid. When dimethyl sulfoxide solution containing FTD-C8-MI is added to an aqueous solution containing PFAS, the emission color of FTD-C8-MI changes from cyan green to red. Therefore, FTD-C8-MI is used as a fluorescent probe, and the fluorescence intensity change and the color change of FTD-C8-MI to PFAS are used to establish quantitative detection of PFOA and PFOS (two common PFAS), so that high sensitivity and high selectivity quantitative detection of different types of PFAS in water medium can be achieved.

[0027] Compared with the traditional ratio type fluorescent probe, the fluorescent probe FTD-C8-MI provided by the application has strong light focusing ability, enhanced FRET (fluorescence resonance energy transfer) to make the probe more sensitive, and can eliminate the interference of other substances in a complex water environment, thereby selectively recognizing PFAS. The high selectivity of the FTD-C8-MI fluorescent probe for PFAS is due to the strong binding affinity of the positively charged and hydrophobic skeleton of the FTD-C8-MI probe and the negatively charged PFAS. Through electrostatic hydrophobic interaction, the probe is aggregated to realize FRET and produce fluorescence color change. Compared with the traditional single-signal output fluorescent probe, the interference of changes in instrument instability, measurement conditions and probe concentration on the detection results can be greatly reduced, and the sensitivity and accuracy are high, the operation is convenient and fast, and it is suitable for on-site detection. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0029] Figure 1 A preparation method flowchart of the AIE type cationic conjugated polymer provided by the embodiment of the present application is shown;

[0030] Figure 2 A synthesis route of the AIE type cationic conjugated polymer provided by the embodiment of the present application is shown;

[0031] Figure 3 A nuclear magnetic resonance hydrogen spectrum of FTD-C8-MI provided by the embodiment of the present application is shown;

[0032] Figure 4 A fluorescence spectrum of FTD-C8-MI provided by the embodiment of the present application for PFOA and PFOS is shown;

[0033] Figure 5 A fluorescence intensity column chart of FTD-C8-MI provided by the embodiment of the present application for different analytes is shown. DETAILED DESCRIPTION

[0034] With reference to the accompanying drawings, the technical solutions in the embodiments of the present application will be clearly and completely described in the description of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way limiting on the present application and its applications or uses. Based on the embodiments in the present application, any person skilled in the art obtains any product same or similar to the present application under the inspiration of the present application or combines the present application with other prior art features, which falls within the protection scope of the present application. In addition, all other embodiments obtained by the ordinary skilled in the art without carrying out creative labor belong to the protection scope of the present application.

[0035] If the specific experimental steps or conditions are not indicated in the embodiments, the operation or conditions of the conventional experimental steps described in the prior art in the field can be used. If the reagents and other instruments used are not indicated by the manufacturer, they are all conventional reagent products that can be obtained by purchase. In addition, the drawings are only schematic illustrations of the embodiments of the present application, and are not necessarily drawn to scale. The same reference numerals in the drawings represent the same or similar parts, and thus repeated description thereof will be omitted. Some block diagrams shown in the drawings are functional entities, and do not necessarily correspond to physically or logically independent entities.

[0036] The technologies, methods and devices known to those skilled in the relevant art can not be discussed in detail, but under appropriate circumstances, the technologies, methods and devices should be regarded as part of the present application.

[0037] In the description of the present application, it should be understood that the use of the words "first", "second" and the like to qualify elements is only for the convenience of distinguishing the corresponding elements, and the above words have no special meaning unless otherwise stated, and therefore cannot be understood as limiting the scope of protection of the present application.

[0038] In addition, the technical features involved in different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0039] The specific implementation content of the present application is as follows:

[0040] In a first aspect, the present application provides an AIE type cationic conjugated polymer, which has the following structural formula:

[0041] .

[0042] In specific implementation, the AIE cationic conjugated polymer FTD-C8-MI provided by the embodiment of the present application has typical aggregation-induced emission (AIE) characteristics and fluorescence resonance energy transfer (FRET), the structural formula of the FTD-C8-MI contains a polyfluorene fluorophore, a triphenylamine (TPA) fluorophore, and a dithiophene benzothiadiazole (DBT) fluorophore containing two long carbon chains, the FTD-C8-MI exhibits cyan green fluorescence under the irradiation of a 365 nm violet light lamp; the FTD-C8-MI can be dissolved in dimethyl sulfoxide and presents a red clear and transparent liquid when a small amount of the FTD-C8-MI is dissolved in water; when the dimethyl sulfoxide solution containing the FTD-C8-MI is added to an aqueous solution containing PFAS, the emission color of the FTD-C8-MI changes from cyan green to red; therefore, the change in fluorescence intensity and the change in chroma of color of the FTD-C8-MI to PFAS can be used to establish quantitative detection of PFOA and PFOS (two common PFAS), and high-sensitivity and high-selectivity quantitative detection of different types of PFAS in a water medium can be achieved.

[0043] In a second aspect, the present application provides a preparation method of an AIE cationic conjugated polymer, Figure 1 A flow chart of the preparation method of the AIE cationic conjugated polymer provided by the embodiment of the present application is shown as follows, Figure 1 As shown in the figure, the preparation method comprises the following steps:

[0044] In step 1, 2,7-dibromo-9,9-di(6-bromohexyl)fluorene, 4,7-bis(5-bromothiophene-2-yl)-5,6-bis(n-octyloxy)-2,1,3-benzothiadiazole, and N-phenyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-N-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)aniline are mixed, then dichloromethane solution is added to form a first solution.

[0045] In this step, the amount ratio of 2,7-dibromo-9,9-di(6-bromohexyl)fluorene, 4,7-bis(5-bromothiophene-2-yl)-5,6-bis(n-octyloxy)-2,1,3-benzothiadiazole, N-phenyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-N-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)aniline, and dichloromethane solution is (0.02-4.0) g:(0.02-2.0) g:(0.02-5.0) g:(10-100) ml.

[0046] Step 2, mixing potassium carbonate and ultrapure water to form a second solution, mixing the first solution and the second solution, adding an appropriate amount of palladium, and then transferring to a reaction at 50 ℃-130 ℃ for 16 h-72 h, and the obtained product is purified by first separation to obtain a precursor polymer;

[0047] In this step, the amount ratio of potassium carbonate to ultrapure water is (0.5-6) g:(1-11) mL; after mixing the first solution and the second solution, the precursor polymer is generated by polymerization under the action of the catalyst palladium; the amount of palladium is 0.01 g-0.20 g; in order to ensure the normal progress of the reaction and avoid the interference of oxygen to the reaction and the generation of impurities, the polymerization reaction is carried out in an oxygen-free environment, and there is no oxygen in the reaction environment; as an example, in the embodiment of the present application, the polymerization reaction is carried out by heating reflux, nitrogen is introduced after mixing the first solution and the second solution, and the oxygen in the mixed solution and the container (a three-necked flask) is discharged, and then the container containing the mixed solution is placed in a heating reflux device to carry out the polymerization reaction.

[0048] In some embodiments, after the polymerization reaction is completed, the process of first separation and purification of the obtained product includes:

[0049] The organic solvent in the obtained product is removed by a rotary evaporator, an appropriate amount of methanol is added for precipitation and centrifugation, water and dichloromethane are added to the collected lower precipitate for organic phase extraction; the obtained organic phase is dried with anhydrous sodium sulfate, and then further rotary evaporation is carried out to remove the organic solvent, and the purified precursor polymer is obtained.

[0050] Step 3, mixing the precursor polymer and 1-methylimidazole, and then transferring to a reaction at 40 ℃-120 ℃ for 16 h-84 h, and the reaction product is purified by second separation to obtain an AIE type cationic conjugated polymer FTD-C8-MI.

[0051] In this step, the amount ratio of the precursor polymer to 1-methylimidazole is (20-100) mg:(1-10) mL; in order to ensure the normal progress of the reaction and avoid the interference of oxygen to the reaction and the generation of impurities, the reaction involved in step 3 is carried out in an oxygen-free environment, and there is no oxygen in the reaction environment; as an example, in the embodiment of the present application, the reaction is carried out by heating reflux, nitrogen is introduced after mixing the precursor polymer and 1-methylimidazole, and the oxygen in the mixed solution and the container (a three-necked flask) is discharged, and then the container containing the mixed solution is placed in a heating reflux device to carry out the reaction.

[0052] In some embodiments, after the reaction is completed, the second separation and purification process of the obtained product includes: adding an appropriate amount of methanol solution to the reaction product, transferring it to a dialysis bag, and dialyzing for 1-3 days; the obtained solid after dialysis is washed with chloroform for multiple times, collected by filtration, and further rotary evaporated to remove the organic solvent, and finally the AIE-type cationic conjugated polymer FTD-C8-MI is obtained.

[0053] Figure 2 The synthesis route of the AIE-type cationic conjugated polymer provided by the embodiments of the present application is shown, and the preparation steps and Figure 2 It can be seen that the AIE-type cationic conjugated polymer FTD-C8-MI is designed and synthesized by using Suzuki cross-coupling polymerization and post-modification synthesis. FTD-C8-MI has obvious aggregation-induced emission (AIE) characteristics and strong interchain fluorescence resonance energy transfer (interchain-FRET) in a good solvent (dimethyl sulfoxide solution), and further exhibits a strong fluorescent emission aggregate state (the emission color of FTD-C8-MI changes from cyan to red) with the addition of an analyte, thereby realizing the detection of the target object.

[0054] In a third aspect, the present application provides an application of the AIE-type cationic conjugated polymer in the first aspect. The AIE-type cationic conjugated polymer FTD-C8-MI has obvious aggregation-induced emission (AIE) characteristics and strong interchain fluorescence resonance energy transfer (interchain-FRET) in a good solvent (dimethyl sulfoxide solution), and further exhibits a strong fluorescent emission aggregate state (the emission color of FTD-C8-MI changes from cyan to red) with the addition of an analyte, thereby realizing the detection of the target object. Therefore, the AIE-type cationic conjugated polymer FTD-C8-MI can be applied to a fluorescent probe.

[0055] In specific implementation, the AIE-type cationic conjugated polymer FTD-C8-MI provided by the present application exhibits cyan green fluorescence under the irradiation of a 365 nm violet light; FTD-C8-MI can be dissolved in dimethyl sulfoxide; the AIE-type cationic conjugated polymer FTD-C8-MI provided by the present application is dissolved in dimethyl sulfoxide to construct a ratiometric fluorescent probe, the concentration of FTD-C8-MI can be 30-70 µM, preferably 50 µM, and it is added to an aqueous solution containing PFAS, and the emission color of FTD-C8-MI changes from cyan to red; therefore, the colorimetric change of PFAS exhibited by FTD-C8-MI can be used to establish quantitative detection of PFOA and PFOS (two common PFAS), and high-sensitivity and high-selectivity quantitative detection of different types of PFAS in water media is realized.

[0056] In order for those skilled in the art to more clearly understand the present application, the AIE-type cationic conjugated polymer, the preparation method and the application are described in detail through the following examples.

[0057] Example 1:

[0058] Take 0.9 g of N-phenyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-N-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl) aniline (M1), 0.6 g of 2,7-dibromo-9,9-di(6-bromohexyl)fluorene (M2), 0.3 g of bis(5-bromothiophene-2-yl)-5,6-bis(n-octyloxy)-2,1,3-benzothiadiazole (M4) in a three-necked flask, add 20 mL of dichloromethane solution to obtain a first solution; mix 0.5 g of potassium carbonate with 3 mL of ultrapure water to form a second solution;

[0059] Add the second solution to the first solution with a syringe, add 0.02 g of zero-valent palladium as a catalyst, pass nitrogen for 10 min, heat at 50 ℃, and condense reflux for 16 h to carry out the polymerization reaction; after the polymerization reaction is completed, remove the organic solvent with a rotary evaporator, drop into methanol to precipitate and centrifuge, collect the lower precipitate; then add water and dichloromethane to extract, collect the organic phase, dry with anhydrous sodium sulfate, and filter; remove the organic solvent by rotary evaporation to obtain a precursor polymer.

[0060] Mix 20 mg of the precursor polymer and 3 mL of 1-methylimidazole, and react at 40 ℃ for 18 h; after the reaction is completed, transfer the reacted liquid to a dialysis bag with a molecular weight of 3 kDa, and dialyze in a methanol solution for 1 day; after dialysis, wash the product with chloroform, filter, then collect the solid on the filter paper with methanol, and remove the solvent by rotary evaporation to obtain the AIE-type cationic conjugated polymer FTD-C8-MI.

[0061] Figure 3 The nuclear magnetic resonance hydrogen spectrum of the AIE-type cationic conjugated polymer FTD-C8-MI provided by the embodiment of the present application is shown in Figure 1. Figure 3 As shown in the nuclear magnetic resonance hydrogen spectrum characterization result, the synthesized product is FTD-C8-MI.

[0062] Example 2:

[0063] Take 1.2 g of N-phenyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-N-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)aniline (M1), 1.0 g of 2,7-dibromo-9,9-di(6-bromohexyl)fluorene (M2), 0.6 g of bis(5-bromothiophen-2-yl)-5,6-bis(n-octyloxy)-2,1,3-benzothiadiazole (M4) in a three-necked flask, add 30 mL of dichloromethane solution to obtain a first solution; 0.8 g of potassium carbonate is mixed with 5 mL of ultrapure water to form a second solution;

[0064] The second solution is added to the first solution with a syringe, 0.06 g of zero-valent palladium is added as a catalyst, nitrogen is introduced for 10 min, heated at 60 ℃, and condensed refluxed for 20 h to carry out the polymerization reaction; after the polymerization reaction is completed, the organic solvent is removed by a rotary evaporator, precipitated into methanol and centrifuged to collect the lower precipitate; then water and dichloromethane are added for extraction, the organic phase is collected, dried with anhydrous sodium sulfate, and filtered; the organic solvent is removed by rotary evaporation to obtain a precursor polymer;

[0065] After 30 mg of the precursor polymer and 4 mL of 1-methylimidazole are mixed, the reaction is carried out at 50 ℃ for 28 h; after the reaction is completed, the reacted liquid is transferred to a dialysis bag with a molecular weight of 3 kDa, and the dialysis bag is placed in a methanol solution for dialysis for 1 day; after dialysis, the product is washed with chloroform, filtered, and then the solid on the filter paper is collected with methanol, and the solvent is removed by rotary evaporation to obtain an AIE-type cationic conjugated polymer FTD-C8-MI.

[0066] The nuclear magnetic resonance hydrogen spectrum of the AIE-type cationic conjugated polymer obtained in this example is the same as the characterization result in Example 1, Figure 3 The nuclear magnetic resonance hydrogen spectrum shown is not repeated here.

[0067] Example 3:

[0068] Take 1.2 g of N-phenyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-N-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)aniline (M1), 1.0 g of 2,7-dibromo-9,9-di(6-bromohexyl)fluorene (M2), 0.6 g of bis(5-bromothiophen-2-yl)-5,6-bis(n-octyloxy)-2,1,3-benzothiadiazole (M4) in a three-necked flask, add 30 mL of dichloromethane solution to obtain a first solution; 0.8 g of potassium carbonate is mixed with 5 mL of ultrapure water to form a second solution;

[0069] The second solution was added to the first solution by using a syringe, 0.10 g of zero-valent palladium was added as a catalyst, nitrogen was bubbled for 10 min, and the polymerization reaction was carried out by heating at 100 ℃ and condensing reflux for 15 h. After the polymerization reaction was completed, the organic solvent was removed by using a rotary evaporator, and the product was precipitated by dropping into methanol and centrifuged. The lower precipitate was collected. Then, water and dichloromethane were added for extraction, and the organic phase was collected, dried with anhydrous sodium sulfate, and filtered. The organic solvent was removed by rotary evaporation to obtain a precursor polymer.

[0070] After 44 mg of the precursor polymer and 5 mL of 1-methylimidazole were mixed, the mixture was reacted at 90 ℃ for 43 h. After the reaction was completed, the reacted liquid was transferred to a dialysis bag with a molecular weight of 3 kDa, and the dialysis bag was placed in a methanol solution for dialysis for 1 day. After dialysis, the product was washed with chloroform, filtered, and then the solid on the filter paper was collected with methanol. The solvent was removed by rotary evaporation to obtain an AIE-type cationic conjugated polymer FTD-C8-MI.

[0071] The nuclear magnetic resonance hydrogen spectrum of the AIE-type cationic conjugated polymer obtained in this example was the same as the characterization result in Example 1 (the nuclear magnetic resonance hydrogen spectrum shown in FIG. 1), and is not repeated here. Figure 3 The nuclear magnetic resonance hydrogen spectrum shown in FIG. 1.

[0072] Example 4:

[0073] 1.3 g of N-phenyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-N-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)aniline (M1), 1.1 g of 2,7-dibromo-9,9-di(6-bromohexyl)fluorene (M2), and 0.7 g of bis(5-bromothiophen-2-yl)-5,6-bis(n-octyloxy)-2,1,3-benzothiadiazole (M4) were added to 35 mL of dichloromethane solution to obtain a first solution. 1.6 g of potassium carbonate was mixed with 6 mL of ultrapure water to form a second solution.

[0074] The second solution was added to the first solution by using a syringe, 0.04 g of zero-valent palladium was added as a catalyst, nitrogen was bubbled for 10 min, and the polymerization reaction was carried out by heating at 60 ℃ and condensing reflux for 21 h. After the polymerization reaction was completed, the organic solvent was removed by using a rotary evaporator, and the product was precipitated by dropping into methanol and centrifuged. The lower precipitate was collected. Then, water and dichloromethane were added for extraction, and the organic phase was collected, dried with anhydrous sodium sulfate, and filtered. The organic solvent was removed by rotary evaporation to obtain a precursor polymer.

[0075] After 26 mg of the precursor polymer and 4 mL of 1-methylimidazole were mixed, the mixture was reacted at 95 ℃ for 38 h; after the reaction was completed, the reacted liquid was transferred to a dialysis bag with a molecular weight of 3 kDa, and the dialysis bag was placed in a methanol solution for dialysis for 1 day; after dialysis was completed, the product was washed with chloroform, filtered, and then the solid remaining on the filter paper was collected with methanol, and the solvent was removed by rotary evaporation to obtain the AIE-type cationic conjugated polymer FTD-C8-MI.

[0076] The hydrogen nuclear magnetic resonance spectrum of the AIE-type cationic conjugated polymer obtained in this example was the same as the characterization result in Example 1 (the hydrogen nuclear magnetic resonance spectrum shown is not repeated here). Figure 3

[0077] Example 5:

[0078] 3.1 g of N-phenyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-N-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)aniline (M1), 2.8 g of 2,7-dibromo-9,9-di(6-bromohexyl)fluorene (M2), and 1.2 g of bis(5-bromothiophen-2-yl)-5,6-bis(n-octyloxy)-2,1,3-benzothiadiazole (M4) were added to 80 mL of dichloromethane to obtain a first solution; 2.3 g of potassium carbonate was mixed with 10 mL of ultrapure water to form a second solution;

[0079] The second solution was added to the first solution by using a syringe, 0.13 g of zero-valent palladium was added as a catalyst, nitrogen was introduced for 10 min, and the mixture was heated at 96 ℃ and condensed to reflux for 22 h to perform a polymerization reaction; after the polymerization reaction was completed, the organic solvent was removed by using a rotary evaporator, methanol was added dropwise to precipitate and centrifuge, and the lower precipitate was collected; then water and dichloromethane were added for extraction, the organic phase was collected, and anhydrous sodium sulfate was used for drying, and then filtration was performed; the organic solvent was removed by rotary evaporation to obtain a precursor polymer;

[0080] After 40 mg of the precursor polymer and 6 mL of 1-methylimidazole were mixed, the mixture was reacted at 90 ℃ for 36 h; after the reaction was completed, the reacted liquid was transferred to a dialysis bag with a molecular weight of 3 kDa, and the dialysis bag was placed in a methanol solution for dialysis for 1 day; after dialysis was completed, the product was washed with chloroform, filtered, and then the solid remaining on the filter paper was collected with methanol, and the solvent was removed by rotary evaporation to obtain the AIE-type cationic conjugated polymer FTD-C8-MI.

[0081] The hydrogen nuclear magnetic resonance spectrum of the AIE-type cationic conjugated polymer obtained in this example was the same as the characterization result in Example 1 (the hydrogen nuclear magnetic resonance spectrum shown is not repeated here). Figure 3 ​The NMR spectra of the AIE-type cationic conjugated polymers obtained in this example are the same as the characterization results in Example 1 (shown in the NMR spectra of the AIE-type cationic conjugated polymers) and are not repeated here.

[0082] Example 6:

[0083] Take 1.6 g of N-phenyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-N-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)aniline (M1), 1.4 g of 2,7-dibromo-9,9-di(6-bromohexyl)fluorene (M2), 0.5 g of bis(5-bromothiophen-2-yl)-5,6-bis(n-octyloxy)-2,1,3-benzothiadiazole (M4) in a three-necked flask, add 33 mL of dichloromethane solution to obtain a first solution; mix 3.2 g of potassium carbonate with 11 mL of ultrapure water to form a second solution;

[0084] Add the second solution to the first solution with a syringe, add 0.09 g of zero-valent palladium as a catalyst, pass nitrogen for 10 min, heat at 110 ℃, and condense reflux for 19 h to carry out the polymerization reaction; after the polymerization reaction is completed, remove the organic solvent with a rotary evaporator, drop into methanol to precipitate and centrifuge, collect the lower precipitate; then add water and dichloromethane to extract, collect the organic phase, dry with anhydrous sodium sulfate, and filter; remove the organic solvent by rotary evaporation to obtain a precursor polymer;

[0085] Mix 46 mg of the precursor polymer and 4 mL of 1-methylimidazole, and react at 65 ℃ for 41 h; after the reaction is completed, transfer the reacted liquid to a dialysis bag with a molecular weight of 3 kDa, and dialyze the dialysis bag in a methanol solution for 1 day; after dialysis is completed, wash the product with chloroform, filter, then collect the solid remaining on the filter paper with methanol, and remove the solvent by rotary evaporation to obtain an AIE-type cationic conjugated polymer FTD-C8-MI.

[0086] The NMR spectra of the AIE-type cationic conjugated polymers obtained in this example are the same as the characterization results in Example 1 (shown in the NMR spectra of the AIE-type cationic conjugated polymers) and are not repeated here. Figure 3 The NMR spectra of the AIE-type cationic conjugated polymers obtained in this example are the same as the characterization results in Example 1 (shown in the NMR spectra of the AIE-type cationic conjugated polymers) and are not repeated here.

[0087] The following experimental examples use FTD-C8-MI provided in Example 1 as the experimental object to carry out

[0088] Experimental Example 1

[0089] Dissolve the AIE-type cationic conjugated polymer FTD-C8-MI in dimethyl sulfoxide to construct a ratiometric fluorescent probe, and apply it to fluorescent detection of different concentrations of PFOA and PFOS:

[0090] The concentration of FTD-C8-MI was kept at 50 µM, the concentration of PFOA was from 0 µM to 26 µM with an interval of 2 µM, the concentration of PFOS was from 0 µM to 40 µM with an interval of 2 µM, the total volume of the test system was 1 mL, the test temperature was 25 ℃, and the excitation wavelength was 370 nm.

[0091] Figure 4 The fluorescence spectrum of PFOA and PFOS exhibited by FTD-C8-MI is shown in the drawings provided by the embodiments of the present application; wherein, Figure 4 the left shows the fluorescence spectrum of PFOA exhibited by FTD-C8-MI, Figure 4 the right shows the fluorescence spectrum of PFOS exhibited by FTD-C8-MI; as Figure 4 shown, with the increase of the concentration of PFOA or PFOS, the fluorescence intensity at 465 nm gradually decreases, and the fluorescence intensity at 645 nm gradually increases. Under the excitation of the ultraviolet lamp, the simultaneous change of the two emission peaks can realize the ratio calculation, reduce the interference of the changes of the instrument instability, measurement conditions and probe concentration on the detection results. At the same time, the fluorescence color of the solution changes from green to red, realizing the naked-eye detection of PFOA and PFOS. From Figure 4 the drawing, it can be seen that the fluorescence intensity of FTD-C8-MI fluorescence probe at 465 nm has a good linear correlation with the concentration of PFOA or PFOS, indicating that the data obtained in the detection analysis has high accuracy, small measurement error and strong reliability of the detection results.

[0092] Experimental Example 2:

[0093] The AIE-type cationic conjugated polymer FTD-C8-MI was dissolved in dimethyl sulfoxide to construct a ratio-type fluorescence probe with the concentration of FTD-C8-MI being 50 µM; and different test systems containing potential interferents were added thereto to test the selectivity of FTD-C8-MI to PFAS and different potential interferents:

[0094] The test system includes the analyte PFOA, PFOS, coexisting substances (E2, DOP, BPA, TC, Lys) interfering surfactants (CTAB, CTAC), anions (Cl − , AC − , CO3 2− , HSO 3− , SO4 2− , HPO 4− , NO 2− ) and cations (Na + , Mn 2+ , Bi 3+ , Fe 3+ , Ce2+ Cu 2+ Cd 2+ Pb 2+ Co 2+ at least two of the following: Cu, Cd, Pb, Co, and Ni, the concentration of each analyte is 10 µM, the total volume of the test system is 1 mL, the test temperature is 25 ℃, and the excitation wavelength is 370 nm.

[0095] Figure 5 The fluorescence intensity column chart of FTD-C8-MI for different analytes is shown, wherein, Figure 5 (A) shows the fluorescence intensity column chart of FTD-C8-MI for analytes, coexisting substances, interfering surfactants, and anions, Figure 5 (B) shows the fluorescence intensity column chart of FTD-C8-MI for analytes and cations; it can be seen from the above figures that the ratio-type fluorescent probe of FTD-C8-MI can selectively and quantitatively detect PFAS, and has excellent selectivity for PFOA and PFOS. This is because PFOA and PFOS have very strong electronegativity compared with other interfering substances, and under the synergistic effect of electrostatic interaction and hydrophobic interaction, the probe aggregation can occur fluorescence resonance energy transfer (FRET), thereby producing strong color change, realizing high-selectivity detection of PFOA and PFOS.

[0096] In the description of the specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in the specification.

[0097] For the method embodiments, in order to simply describe, they are all expressed as a series of action combinations, but those skilled in the art should know that the present application is not limited by the order of the described actions, because according to the present application, certain steps can be performed in other order or simultaneously. Secondly, those skilled in the art should know that the embodiments described in the specification are all preferred embodiments, and the actions and components involved are not necessarily necessary for the present application.

[0098] The above describes in detail the AIE type cation conjugated polymer, the preparation method and the application provided by the application. The principles and implementation manners of the application are described by using specific examples. The above examples are only used to help understand the method of the application and the core idea thereof. Meanwhile, for those skilled in the art, the specific implementation manners and application ranges can be changed according to the idea of the application. In conclusion, the content of the specification should not be understood as a limitation of the application.

Claims

1. An AIE-type cationic conjugated polymer, characterized in that, The AIE type cationic conjugated polymer has the following structural formula: 。 2. A method for preparing the AIE-type cationic conjugated polymer of claim 1, characterized in that, The preparation method comprises the following steps: Step 1, after mixing 2,7-dibromo-9,9-di(6-bromohexyl)fluorene, 4,7-bis(5-bromothiophene-2-yl)-5,6-bis(n-octyloxy)-2,1,3-benzothiadiazole and N-phenyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-N-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)aniline, dichloromethane solution is added to form a first solution; Step 2, potassium carbonate and ultrapure water are mixed to form a second solution, the first solution is mixed with the second solution, and after adding an appropriate amount of palladium, it is transferred to 50 DEG C~130 DEG C for reaction for 16 h~72 h, and the obtained product is purified by first separation to obtain a precursor polymer; Step 3, after mixing the precursor polymer and 1-methylimidazole, it is transferred to 40 DEG C~120 DEG C for reaction for 16 h~84 h, and the reaction product is purified by second separation to obtain the AIE type cationic conjugated polymer FTD-C8-MI.

3. The method of claim 2, wherein the AIE-type cationic conjugated polymer is prepared by the reaction of the compound of formula (1) with the compound of formula (2) in the presence of a base. In step 1, the amount ratio of 2,7-dibromo-9,9-di(6-bromohexyl)fluorene, 4,7-bis(5-bromothiophene-2-yl)-5,6-bis(n-octyloxy)-2,1,3-benzothiadiazole, N-phenyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-N-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)aniline and dichloromethane solution is (0.02~4.0) g:(0.02~2.0) g:(0.02~5.0) g:(10~100) ml.

4. The method of claim 2, wherein the AIE-type cationic conjugated polymer is prepared by the reaction of the compound of formula (1) with the compound of formula (2) in the presence of a base. In step 2, the amount ratio of potassium carbonate and ultrapure water is (0.5~6) g:(1~11) mL.

5. The method of claim 2, wherein the AIE-type cationic conjugated polymer is prepared by the reaction of the compound of formula (1) with the compound of formula (2) in the presence of a base. In step 2, the amount of palladium is 0.01 g~0.20 g.

6. The method for preparing the AIE-type cationic conjugated polymer according to claim 2, characterized in that, In step 2, the first separation and purification comprises: The organic solvent in the obtained product is removed by using a rotary evaporator, an appropriate amount of methanol is added for precipitation and centrifugation, water and dichloromethane are added to the collected lower precipitate for organic phase extraction; The obtained organic phase is dried by anhydrous sodium sulfate, and then further rotary evaporation is performed to remove the organic solvent, so that the purified precursor polymer is obtained.

7. The method for preparing the AIE-type cationic conjugated polymer according to claim 2, characterized in that, In step 3, the amount ratio of the precursor polymer and 1-methylimidazole is (20~100) mg:(1~10) mL.

8. The method for preparing the AIE-type cationic conjugated polymer according to claim 2, characterized in that, In step 3, the second separation and purification comprises: An appropriate amount of methanol solution is added to the reaction product, and then transferred to a dialysis bag for dialysis for 1-3 days; The dialysis obtained solid is washed with chloroform for multiple times, and then collected by filtration, and further rotary evaporation is performed to remove the organic solvent, so that the AIE type cationic conjugated polymer FTD-C8-MI is obtained.

9. Use of the AIE-type cationic conjugated polymer according to claim 1, characterized in that, The AIE type cationic conjugated polymer is applied to a fluorescent probe.

10. The use of the AIE-type cationic conjugated polymer according to claim 9, characterized in that, The AIE-type cationic conjugated polymer is dissolved in dimethyl sulfoxide to construct a ratiometric fluorescent probe for selective and quantitative detection of PFAS.

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