An AIE-type cationic conjugated polymer, its preparation method and application

Abstract

This invention provides an AIE-type cationic conjugated polymer, its preparation method, and its applications. The invention uses a functionalized tetraphenylethylene structure as the donor unit and achieves emission at different wavelengths by adjusting the acceptor structure. This AIE-type cationic conjugated polymer, as a type of activation probe, overcomes the aggregation and fluorescence quenching problem of traditional conjugated polymer probes, enabling a color change from dark to bright. The AIE-type cationic conjugated polymer of this invention possesses abundant cationic structures and hydrophobic alkyl chains, enabling more efficient capture of target analytes through the synergistic effects of electrostatic and hydrophobic interactions, and has great potential for achieving high-sensitivity and high-accuracy detection of target analytes.

Description

Technical Field

[0001] This invention relates to the field of fluorescent probe technology, and in particular to an AIE-type cationic conjugated polymer, its preparation method, and its application. Background Technology

[0002] The development of conjugated polymers began in the 1960s. These polymers possess alternating single and double bond structures, typically composed of donor-acceptor structures, a characteristic that endows them with unique optoelectronic properties. Conjugated polymers generally exhibit significant light absorption and emission properties, capable of producing fluorescence and phosphorescence in the visible and ultraviolet light regions. Some conjugated polymers, such as polyaniline and polythiophene, can exhibit semiconductor behavior and even conductivity under certain conditions, leading to their widespread application in electronic devices.

[0003] The luminescent properties of conjugated polymers make them suitable as probes for the detection of specific targets. Due to their unique delocalized π-bond structure, they exhibit a "molecular wire" effect, meaning that when any fluorescent group in the polymer interacts with the target, it can trigger the response of all groups on the main chain, thereby amplifying the response signal and improving detection sensitivity.

[0004] However, similar to traditional fluorescent probes, conjugated polymers also suffer from aggregation quenching of fluorescence, which in turn affects their own luminescence properties. Summary of the Invention

[0005] To address the aforementioned problems in the prior art, this invention provides an AIE-type cationic conjugated polymer, its preparation method, and its application, thereby solving the problem of fluorescence quenching caused by aggregation of fluorescent probes in existing methods.

[0006] The specific details of the invention are as follows:

[0007] In a first aspect, the present invention provides an AIE-type cationic conjugated polymer, said AIE-type cationic conjugated polymer having the structural formula shown in Formula I:

[0008]

[0009] Formula I

[0010] Wherein, R is selected from any of the following structures:

[0011] .

[0012] In a second aspect, the present invention provides a method for preparing the AIE-type cationic conjugated polymer described in the first aspect above, the method comprising the following steps:

[0013] Step 1: Mix [1,1-bis(4-bromophenyl)-2,2-bis(4-hydroxyphenyl)]ethylene, cesium carbonate, and anhydrous acetone solution to form the first solution; mix 3-chloro-1-(N,N-dimethyl)propylamine with N,N-dimethylformamide solution to form the second solution;

[0014] Step 2: Mix the first solution with the second solution and place the mixture at 45℃~120℃ for 6 h~12 h. After the product is purified by the first separation process, the first monomer is obtained.

[0015] Step 3: Mix the first monomer, the acceptor fluorophore R, and the toluene solution to form the third solution; add the potassium carbonate solution to the ultrapure water to form the fourth solution;

[0016] Step 4: Mix the third solution with the fourth solution, degas the mixture, add tetra(triphenylphosphine)palladium, and react at 60 ℃~120 ℃ for 6 h~48 h. The resulting product is then purified by a second separation process to obtain the precursor polymer CPs.

[0017] Step 5: Mix the precursor polymer CPs, (3-bromopropyl)trimethylammonium bromide and tetrahydrofuran / methanol mixture, and react at 45 ℃~80 ℃ for 12 h~48 h. After the product is purified by the third separation, AIE-type cationic conjugated polymer AIE-CPs is obtained.

[0018] The receptor fluorophore R has any of the following structures:

[0019] .

[0020] Optionally, in step 1, the ratio of the amounts of [1,1-bis(4-bromophenyl)-2,2-bis(4-hydroxyphenyl)]ethylene, cesium carbonate, and anhydrous acetone solution is (0.1~1.0) g : (0.1~1.2) g : (25~100) mL; and / or

[0021] The ratio of 3-chloro-1-(N,N-dimethyl)propylamine to N,N-dimethylformamide is (0.1~1.2) g : (10~100) mL.

[0022] Optionally, in step 2, the first separation and purification includes:

[0023] The organic solvent in the obtained product was removed by rotary evaporation, and then saturated sodium chloride aqueous solution and dichloromethane were added for organic phase extraction.

[0024] The obtained organic phase was dried with anhydrous sodium sulfate, and then the organic solvent was removed by rotary evaporation. The purified first monomer was obtained by column chromatography.

[0025] Optionally, in step 3, the ratio of the first monomer, the receptor fluorophore R, and the toluene solution is (0.1~1.0) g : (0.05~0.5) g : (10~100) mL; and / or

[0026] The ratio of potassium carbonate to ultrapure water is (0.5~5.0) g : (1~10) mL.

[0027] Optionally, in step 4, the amount of the tetra(triphenylphosphine)palladium catalyst used is 2 ~ 20 mg / ml (0.005 g ~ 0.020 g).

[0028] Optionally, in step 4, the second separation and purification includes:

[0029] The organic solvent in the obtained product was removed by rotary evaporation, and then water and dichloromethane were added for organic phase extraction.

[0030] The obtained organic phase was dried with anhydrous sodium sulfate and then further removed by rotary evaporation to obtain the purified precursor polymer CPs.

[0031] Optionally, in step 5, the tetrahydrofuran / methanol mixture is formed by mixing tetrahydrofuran and methanol in equal volumes; and / or

[0032] The ratio of the precursor polymer CPs, (3-bromopropyl)trimethylammonium bromide, and tetrahydrofuran / methanol mixture is (0.01~0.1)g:(0.05~1.0)g:(10~100)mL.

[0033] Optionally, in step 5, the third separation and purification includes:

[0034] After removing tetrahydrofuran and methanol from the obtained product using a rotary evaporator, a methanol solution was added to dissolve it.

[0035] The resulting mixture was dialyzed for 1-3 days. The solid obtained from the dialyzing was washed three times with dichloromethane and dried to obtain AIE-type cationic conjugated polymers AIE-CPs.

[0036] Thirdly, the present invention provides an application of an AIE-type cationic conjugated polymer, wherein the AIE-type cationic conjugated polymer described in the first aspect is applied to a fluorescent probe.

[0037] Compared with the prior art, the present invention has the following advantages:

[0038] This invention provides an AIE-type cationic conjugated polymer. The invention uses a functionalized tetraphenylethylene structure as the donor unit and achieves emission at different wavelengths by adjusting the acceptor structure. As an on-off probe, this AIE-type cationic conjugated polymer overcomes the aggregation-induced fluorescence quenching problem of traditional conjugated polymer probes, enabling a color change from dark to bright. The AIE-type cationic conjugated polymer of this invention possesses abundant cationic structures and hydrophobic alkyl chains, enabling more efficient capture of target analytes through the synergistic effects of electrostatic and hydrophobic interactions, and has great potential for achieving high-sensitivity and high-accuracy detection of target analytes. Attached Figure Description

[0039] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0040] Figure 1 A flowchart illustrating the preparation method of the AIE-type cationic conjugated polymer provided in an embodiment of the present invention is shown.

[0041] Figure 2 The synthetic route of the AIE-type cationic conjugated polymer provided in the embodiments of the present invention is shown;

[0042] Figure 3 The nuclear magnetic resonance hydrogen spectrum of the AIE-type cationic conjugated polymer provided in the embodiments of the present invention is shown;

[0043] Figure 4 The fluorescence intensity characterization diagram of the AIE-type cationic conjugated polymer provided in the embodiments of the present invention is shown. Detailed Implementation

[0044] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention. Furthermore, all other embodiments obtained by those skilled in the art without inventive effort are within the protection scope of the present invention.

[0045] Specific experimental steps or conditions are not specified in the embodiments; they can be performed according to the conventional experimental steps or conditions described in the prior art. Reagents and other instruments used, unless otherwise specified, are all commercially available conventional reagent products. Furthermore, the accompanying drawings are merely illustrative diagrams of the embodiments of the present invention and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and therefore, repeated descriptions of them will be omitted. Some block diagrams shown in the drawings are functional entities and do not necessarily correspond to physically or logically independent entities.

[0046] Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of this specification.

[0047] In the description of this invention, it should be understood that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0048] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0049] The specific implementation details of this invention are as follows:

[0050] In a first aspect, the present invention provides an AIE-type cationic conjugated polymer, said AIE-type cationic conjugated polymer having the structural formula shown in Formula I:

[0051]

[0052] Formula I

[0053] Wherein, R is selected from any of the following structures:

[0054] .

[0055] In specific implementations, this invention uses a functionalized tetraphenylethylene structure as the donor unit, and achieves emission at different wavelengths by adjusting the acceptor structure R. Compared with traditional conjugated polymer fluorescent probes, the AIE-type cationic conjugated polymer provided in this invention overcomes the aggregation-induced fluorescence quenching (ACQ) problem of traditional conjugated polymers. Due to the introduction of the AIE donor unit, the ACQ problem is overcome, and aggregation-induced emission (AIE) occurs, thereby achieving a change in the fluorescent probe color from dark to bright. Compared with traditional cationic conjugated polymer fluorescent probes, the AIE-type cationic conjugated polymer provided in this invention has abundant cationic structures and hydrophobic alkyl chains that can more efficiently capture target molecule. The high-efficiency capture is due to the synergistic effect of electrostatic and hydrophobic interactions, which promotes the efficient binding of the probe to the target molecule.

[0056] The polymer provided in this invention uses TPE as the donor unit, which is essentially an AIE molecule, meaning it possesses aggregation-induced emission properties. In its aggregated state, it exhibits bright emission enhancement characteristics, unlike traditional ACQ (aggregation-quenched fluorescence) molecules which exhibit weak or no fluorescence emission in the aggregated state. This solves the problem of fluorescence quenching in traditional fluorescent molecules in the aggregated state.

[0057] Secondly, the present invention provides a method for preparing an AIE-type cationic conjugated polymer. Figure 1 A flowchart illustrating the preparation method of the AIE-type cationic conjugated polymer provided in this embodiment of the invention is shown, as follows: Figure 1 As shown, the preparation method includes the following steps:

[0058] Step 1: Mix [1,1-bis(4-bromophenyl)-2,2-bis(4-hydroxyphenyl)]ethylene, cesium carbonate, and anhydrous acetone solution to form a first solution; mix 3-chloro-1-(N,N-dimethyl)propylamine with N,N-dimethylformamide solution to form a second solution.

[0059] In this step, the ratio of [1,1-bis(4-bromophenyl)-2,2-bis(4-hydroxyphenyl)]ethylene, cesium carbonate, and anhydrous acetone solution is (0.1~1.0)g : (0.1~1.2)g : (25~100)mL; the ratio of 3-chloro-1-(N,N-dimethyl)propylamine to N,N-dimethylformamide is (0.1~1.2)g : (10~100)mL.

[0060] Step 2: Mix the first solution with the second solution and place the mixture at 45℃~120℃ for 6 h~12 h. After the product is purified by the first separation process, the first monomer is obtained.

[0061] In this step, after the first solution and the second solution are mixed, a substitution reaction is carried out to generate the first monomer. To ensure the normal progress of the reaction and to avoid the interference of oxygen and the generation of impurities, the substitution reaction is carried out in an oxygen-isolated environment. As an example, in this embodiment of the invention, the substitution reaction is carried out by heating and reflux. After the first solution and the second solution are mixed, nitrogen gas is introduced to purge the oxygen from the mixed solution and the container (three-necked flask). Then, the container holding the mixed solution is placed in the heating and reflux device to carry out the substitution reaction.

[0062] In some embodiments, the first separation and purification process of the resulting product after the substitution reaction is completed includes:

[0063] The organic solvent in the obtained product was removed by rotary evaporation, and then saturated sodium chloride aqueous solution and dichloromethane were added for organic phase extraction.

[0064] The organic phase obtained by extraction was dried with anhydrous sodium sulfate, filtered, and then the dichloromethane organic solvent was removed by rotary evaporation. The product was then eluted by column chromatography to obtain the purified first monomer.

[0065] Step 3: Mix the first monomer, the acceptor fluorophore R, and the toluene solution to form the third solution; add the potassium carbonate solution to the ultrapure water to form the fourth solution;

[0066] In this step, the receptor fluorophore R has any of the following structures: ;

[0067] The ratio of the first monomer, the acceptor fluorophore R, and the toluene solution in the third solution is (0.1~1.0) g : (0.05~0.5) g : (10~100) mL; the ratio of potassium carbonate to ultrapure water is (0.5~5.0) g : (1~10) mL.

[0068] Step 4: Mix the third solution with the fourth solution, degas the mixture, add tetra(triphenylphosphine)palladium, and react at 60 ℃~120 ℃ for 6 h~48 h. The resulting product is then purified by a second separation process to obtain the precursor polymer CPs.

[0069] In this step, the third and fourth solutions undergo polymerization in the presence of the catalyst tetra(triphenylphosphine)palladium. After polymerization, the resulting product is purified by a second separation process to obtain the precursor polymer CPs. The amount of tetra(triphenylphosphine)palladium catalyst used is 2-20 mg / ml (0.005 g-0.020 g). To ensure the normal progress of the polymerization reaction and to avoid interference from oxygen and the generation of impurities, the polymerization reaction is carried out in an oxygen-isolated environment. As an example, in this embodiment of the invention, the substitution reaction is carried out by heating and reflux. After mixing the first and second solutions, degassing is performed by introducing nitrogen gas to remove oxygen from the mixed solution and the container (three-necked flask). Then, the container holding the mixed solution is placed in a heating and reflux apparatus to carry out the polymerization reaction.

[0070] In some embodiments, after the polymerization reaction is completed, the second separation and purification process of the obtained product includes: removing the organic solvent from the obtained product using a rotary evaporator, and then adding water and dichloromethane for organic phase extraction; after drying the obtained organic phase with anhydrous sodium sulfate, further removing the organic solvent by rotary evaporation to obtain the purified precursor polymer CPs.

[0071] Step 5: Mix the precursor polymer CPs, (3-bromopropyl)trimethylammonium bromide and tetrahydrofuran / methanol mixture, and react at 45 ℃~80 ℃ for 12 h~48 h. After the product is purified by the third separation, AIE-type cationic conjugated polymer AIE-CPs is obtained.

[0072] In this step, the tetrahydrofuran / methanol mixture is a mixture formed by mixing tetrahydrofuran and methanol in equal volumes; the ratio of the precursor polymer CPs, (3-bromopropyl)trimethylammonium bromide and the tetrahydrofuran / methanol mixture is (0.01~0.1)g:(0.05~1.0)g:(10~100)mL.

[0073] In some embodiments, the third separation and purification includes the following process: after removing tetrahydrofuran and methanol from the obtained product using a rotary evaporator, a methanol solution is added for dissolution; the resulting mixture is dialyzed for 1-3 days, and the solid obtained from dialyzing is washed three times with dichloromethane and dried to obtain AIE-type cationic conjugated polymers AIE-CPs.

[0074] Figure 2 The synthetic route of the AIE-type cationic conjugated polymer provided in the embodiments of the present invention is shown, in conjunction with the above preparation steps and Figure 2As can be seen, this invention employs Suzuki cross-coupling polymerization and post-modification synthesis to design and synthesize a color-tunable AIE-type cationic conjugated polymer. It exhibits a weakly fluorescent dispersed state in good solvents, and then displays a strongly fluorescent aggregated state with the addition of unsuitable solvents or analytes, causing the luminescence color of the solution to change from dark to bright, thereby achieving the detection of the target analyte. The AIE-type cationic conjugated polymer provided by this invention, as an activated fluorescent probe, is the first to utilize the structure of the acceptor and introduce an AIE donor structure to achieve AIE-type cationic conjugated polymers with different emission wavelengths.

[0075] Thirdly, the present invention provides an application of an AIE-type cationic conjugated polymer, wherein the AIE-type cationic conjugated polymer provided in the first aspect is used in the preparation of fluorescent probes.

[0076] In specific implementation, the AIE-type cationic conjugated polymer provided by this invention contains a functionalized tetraphenylethylene donor fluorophore and an R-acceptor fluorophore. Compared with traditional conjugated polymer fluorescent probes, the AIE-type cationic conjugated polymer provided by this invention can overcome the aggregation-induced fluorescence quenching (ACQ) problem of traditional conjugated polymers. Due to the introduction of the AIE donor structural unit, the ACQ problem is overcome, and aggregation-induced emission (AIE) occurs, thereby realizing the color change of the fluorescent probe from dark to bright. Simultaneously, compared with traditional cationic conjugated polymer fluorescent probes, the AIE-type cationic conjugated polymer provided by this invention, with its abundant cationic structure and hydrophobic alkyl chains, can more efficiently capture target analytes. This high-efficiency capture is due to the synergistic effect of electrostatic and hydrophobic interactions, promoting efficient binding between the probe and the target molecule. Applying it to fluorescent probes can overcome the aggregation-induced fluorescence quenching problem of traditional conjugated polymers and endow the conjugated polymer probe with a novel mechanism of action, thus giving the conjugated polymer excellent sensing and imaging performance.

[0077] To enable those skilled in the art to more clearly understand the present invention, the following examples will provide a detailed description of an AIE-type cationic conjugated polymer, its preparation method, and its applications.

[0078] Example 1:

[0079] 0.1 g of [1,1-bis(4-bromophenyl)-2,2-bis(4-hydroxyphenyl)]ethylene and 0.1 g of Cs₂CO₃ were placed in a three-necked flask, and 25 mL of anhydrous acetone solution was added to obtain the first solution. 0.1 g of 3-chloro-1-(N,N-dimethyl)propylamine was dissolved in 10 mL of anhydrous DMF to obtain the second solution. The second solution was slowly added to the first solution, and the substitution reaction was carried out under nitrogen protection at 45 °C for 6 h. After the substitution reaction was completed, the organic solvent was removed by rotary evaporation, and the mixture was extracted with saturated NaCl solution and dichloromethane. The organic phase was collected, dried over anhydrous sodium sulfate, and filtered. The first monomer was obtained by column chromatography elution purification.

[0080] 0.1 g of the first monomer and 0.05 g of 4,7-bis(4,4,5,5-tetramethyl-1,3,2-dioxapentoboran-2-yl)-2,1,3-benzothiadiazole were placed in a three-necked flask, and 10 mL of toluene solution was added to obtain the third solution. 0.5 g of potassium carbonate was mixed with 1 mL of ultrapure water to obtain the fourth solution. The fourth solution was added to the third solution using a syringe, and the mixture was degassed for 30 min. 0.005 g of tetrakis(triphenylphosphine)palladium was added as a catalyst, and nitrogen gas was introduced for 30 min. The mixture was heated to reflux at 60 °C for 6 h to carry out the polymerization reaction. After the polymerization reaction was completed, the organic solvent was removed by rotary evaporation, and the mixture was extracted with water and dichloromethane. The organic phase was collected, dried with anhydrous sodium sulfate, and filtered. The organic solvent was removed by rotary evaporation to obtain the precursor polymer CPs. 0.01 g of CPs, 0.05 g of (3-bromopropyl)trimethylammonium bromide, and 10 mL of a tetrahydrofuran / methanol mixture were mixed and reacted at 45 °C for 12 h. After the reaction, the organic solvent was removed by rotary evaporation. 1 mL of methanol was added to dissolve the CPs, and the mixture was transferred to a dialysis bag with a molecular weight of 2.5 kDa and dialyzed for 3 days. After further removal of the organic solvent by rotary evaporation, the AIE-type cationic conjugated polymer AIE-CPs (in structural formula I, the acceptor fluorescent group R is...) was obtained. ).

[0081] Figure 3 The following is a hydrogen nuclear magnetic resonance spectrum of the AIE-type cationic conjugated polymer provided in an embodiment of the present invention, as shown. Figure 3 As shown, Figure 3 The proton characteristic peaks shown are: 1 ¹H NMR (400 MHz, CH₃OD, δ): δ 7.54–6.73 (br, aromatic H), δ 4.08 (br, O-CH₂-), δ 3.54 (br, N-CH₂-), δ 3.27 (br, N-CH₃), δ 2.44 (br, -CH₂-). This indicates that the synthesized product is identified as AIE-CPs.

[0082] Figure 4 The fluorescence intensity characterization diagram of the AIE-type cationic conjugated polymer provided in the embodiments of the present invention is shown, as follows: Figure 4 As shown in the figure, the horizontal axis represents the percentage content of the undesirable solvent tetrahydrofuran (THF), and the vertical axis represents the ratio of the fluorescence intensity value to the initial fluorescence intensity value. With the increase of the undesirable solvent THF, the aggregation degree of the AIE probe increases, and the fluorescence intensity increases.

[0083] Example 2:

[0084] 0.3 g of [1,1-bis(4-bromophenyl)-2,2-bis(4-hydroxyphenyl)]ethylene and 0.3 g of Cs₂CO₃ were placed in a three-necked flask, and 40 mL of anhydrous acetone solution was added to obtain the first solution. 0.3 g of 3-chloro-1-(N,N-dimethyl)propylamine was dissolved in 30 mL of anhydrous DMF to obtain the second solution. The second solution was slowly added to the first solution, and the substitution reaction was carried out under nitrogen protection at 45 °C for 8 h. After the substitution reaction was completed, the organic solvent was removed by rotary evaporation, and the mixture was extracted with saturated NaCl solution and dichloromethane. The organic phase was collected, dried over anhydrous sodium sulfate, and filtered. The first monomer was obtained by column chromatography elution purification.

[0085] 0.3 g of the first monomer and 0.15 g of 1,4-phenyldiborate bis(pinacol) ester were placed in a three-necked flask, and 30 mL of toluene solution was added to obtain the third solution. 1.0 g of potassium carbonate was mixed with 2 mL of ultrapure water to obtain the fourth solution. The fourth solution was added to the third solution using a syringe, and the mixture was degassed for 30 min. 0.008 g of tetra(triphenylphosphine)palladium was added as a catalyst, and nitrogen gas was introduced for 30 min. The mixture was heated to reflux at 80 °C for 18 h to carry out the polymerization reaction. After the polymerization reaction was completed, the organic solvent was removed by rotary evaporation, and water and dichloromethane were added for extraction. The organic phase was collected, dried with anhydrous sodium sulfate, and filtered. The organic solvent was removed by rotary evaporation to obtain the precursor polymer CPs. 0.03 g of CPs, 0.15 g of (3-bromopropyl)trimethylammonium bromide, and 30 mL of a tetrahydrofuran / methanol mixture were mixed and reacted at 50 °C for 18 h. After the reaction, the organic solvent was removed by rotary evaporation. 1 mL of methanol was added to dissolve the CPs, and the mixture was transferred to a dialysis bag with a molecular weight of 2.5 kDa and dialyzed for 3 days. After further removal of the organic solvent by rotary evaporation, the AIE-type cationic conjugated polymer AIE-CPs (in structural formula I, the acceptor fluorescent group R is...) was obtained. ).

[0086] The 1H NMR spectrum of the AIE-type cationic conjugated polymer obtained in this embodiment is compared with the characterization results in Example 1. Figure 3 The shown proton NMR spectrum and Figure 4 The fluorescence intensity characterization diagram shown is similar and will not be repeated here.

[0087] Example 3:

[0088] 0.5 g of [1,1-bis(4-bromophenyl)-2,2-bis(4-hydroxyphenyl)]ethylene and 0.6 g of Cs₂CO₃ were placed in a three-necked flask, and 60 mL of anhydrous acetone solution was added to obtain the first solution. 0.6 g of 3-chloro-1-(N,N-dimethyl)propylamine was dissolved in 50 mL of anhydrous DMF to obtain the second solution. The second solution was slowly added to the first solution, and the substitution reaction was carried out under nitrogen protection at 45 °C for 9 h. After the substitution reaction was completed, the organic solvent was removed by rotary evaporation, and the mixture was extracted with saturated NaCl solution and dichloromethane. The organic phase was collected, dried over anhydrous sodium sulfate, and filtered. Column chromatography was used for elution and purification to obtain the first monomer.

[0089] 0.5 g of the first monomer and 0.25 g of 4,7-bis[5-(4,4,5,5-tetramethyl-1,3,2-dioxoboronyl-2-yl)-2-thienyl]-2,1,3-benzothiadiazole were placed in a three-necked flask, and 50 mL of toluene solution was added to obtain the third solution. 2.0 g of potassium carbonate was mixed with 4 mL of ultrapure water to obtain the fourth solution. The fourth solution was added to the third solution using a syringe, and the mixture was degassed for 30 min. 0.010 g of tetra(triphenylphosphine)palladium was added as a catalyst, and nitrogen gas was introduced for 30 min. The mixture was heated to reflux at 95 °C for 24 h to carry out the polymerization reaction. After the polymerization reaction was completed, the organic solvent was removed by rotary evaporation, and the mixture was extracted with water and dichloromethane. The organic phase was collected, dried with anhydrous sodium sulfate, and filtered. The organic solvent was removed by rotary evaporation to obtain the precursor polymer CPs. 0.05 g of CPs, 0.25 g of (3-bromopropyl)trimethylammonium bromide, and 50 mL of a tetrahydrofuran / methanol mixture were mixed and reacted at 60 °C for 24 h. After the reaction, the organic solvent was removed by rotary evaporation. 1 mL of methanol was added to dissolve the CPs, and the mixture was transferred to a dialysis bag with a molecular weight of 2.5 kDa and dialyzed for 3 days. After further removal of the organic solvent by rotary evaporation, the AIE-type cationic conjugated polymer AIE-CPs (in structural formula I, the acceptor fluorescent group R is...) was obtained. ).

[0090] The structural formula of 4,7-bis[5-(4,4,5,5-tetramethyl-1,3,2-dioxoborhexacyclopentan-2-yl)-2-thienyl]-2,1,3-benzothiadiazole is as follows:

[0091] .

[0092] The 1H NMR spectrum of the AIE-type cationic conjugated polymer obtained in this embodiment is compared with the characterization results in Example 1. Figure 3 The shown proton NMR spectrum and Figure 4 The fluorescence intensity characterization diagram shown is similar and will not be repeated here.

[0093] Example 4:

[0094] 0.8 g of [1,1-bis(4-bromophenyl)-2,2-bis(4-hydroxyphenyl)]ethylene and 0.9 g of Cs₂CO₃ were placed in a three-necked flask, and 80 mL of anhydrous acetone solution was added to obtain the first solution. 0.9 g of 3-chloro-1-(N,N-dimethyl)propylamine was dissolved in 70 mL of anhydrous DMF to obtain the second solution. The second solution was slowly added to the first solution, and the substitution reaction was carried out under nitrogen protection at 45 °C for 10 h. After the substitution reaction was completed, the organic solvent was removed by rotary evaporation, and the mixture was extracted with saturated NaCl solution and dichloromethane. The organic phase was collected, dried over anhydrous sodium sulfate, and filtered. The first monomer was obtained by column chromatography elution purification.

[0095] 0.8 g of the first monomer and 0.4 g of 1H,5H-phenyl[1,2-c:4,5-c"]bis([1,2,5]thiadiazole)-4,8-bis(pinacol borate) were placed in a three-necked flask, and 80 mL of toluene solution was added to obtain the third solution. 3.0 g of potassium carbonate was mixed with 8 mL of ultrapure water to obtain the fourth solution. The fourth solution was added to the third solution using a syringe, and the mixture was degassed for 30 min. 0.015 g of tetrakis(triphenylphosphine)palladium was added as a catalyst, and nitrogen gas was introduced for 30 min. The mixture was heated to reflux at 105 °C for 36 h to carry out the polymerization reaction. After the polymerization reaction, the organic solvent was removed by rotary evaporation, and water and dichloromethane were added for extraction. The organic phase was collected, dried with anhydrous sodium sulfate, and filtered. The organic solvent was removed by rotary evaporation to obtain the precursor polymer CPs. 0.08 g of CPs, 0.4 g of (3-bromopropyl)trimethylammonium bromide, and 75 g of... A mixture of 1 mL tetrahydrofuran and methanol in equal proportions was mixed and reacted at 65 °C for 36 h. After the reaction, the organic solvent was removed by rotary evaporation. 1 mL of methanol was added to dissolve the solvent, and the mixture was transferred to a dialysis bag with a molecular weight of 2.5 kDa and dialyzed for 3 days. After further removal of the organic solvent by rotary evaporation, AIE-type cationic conjugated polymers AIE-CPs (where the acceptor fluorescent group R in structural formula I is...) were obtained. ).

[0096] The structural formula of 1H,5H-benzyl[1,2-c:4,5-c"]bis([1,2,5]thiadiazole)-4,8-bis(pinacol borate) is as follows:

[0097] .

[0098] The 1H NMR spectrum of the AIE-type cationic conjugated polymer obtained in this embodiment is compared with the characterization results in Example 1. Figure 3 The shown proton NMR spectrum and Figure 4 The fluorescence intensity characterization diagram shown is similar and will not be repeated here.

[0099] Example 5:

[0100] 1.0 g of [1,1-bis(4-bromophenyl)-2,2-bis(4-hydroxyphenyl)]ethylene and 1.2 g of Cs₂CO₃ were placed in a three-necked flask, and 100 mL of anhydrous acetone solution was added to obtain the first solution. 1.2 g of 3-chloro-1-(N,N-dimethyl)propylamine was dissolved in 100 mL of anhydrous DMF to obtain the second solution. The second solution was slowly added to the first solution, and the substitution reaction was carried out under nitrogen protection at 45 °C for 12 h. After the substitution reaction was completed, the organic solvent was removed by rotary evaporation, and the mixture was extracted with saturated NaCl solution and dichloromethane. The organic phase was collected, dried over anhydrous sodium sulfate, and filtered. The first monomer was obtained by column chromatography elution purification.

[0101] 1.0 g of the first monomer and 0.5 g of 4,7-bis(5-(4,4,5,5-tetramethyl-1,3,2-dioxoboronyl-2-yl)thiophene-2-yl)benzo[c]bis([1,2,5])thiadiazole were placed in a three-necked flask, and 100 mL of toluene solution was added to obtain the third solution. 5.0 g of potassium carbonate was mixed with 10 mL of ultrapure water to obtain the fourth solution. The fourth solution was added to the third solution using a syringe, and the mixture was degassed for 30 min. 0.020 g of tetra(triphenylphosphine)palladium was added as a catalyst, and nitrogen gas was introduced for 30 min. The mixture was heated to reflux at 120 °C for 48 h to carry out the polymerization reaction. After the polymerization reaction was completed, the organic solvent was removed by rotary evaporation, and water and dichloromethane were added for extraction. The organic phase was collected, dried with anhydrous sodium sulfate, and filtered. The organic solvent was removed by rotary evaporation to obtain the precursor polymer CPs. 0.1 g of CPs, 0.5 g of (3-bromopropyl)trimethylammonium bromide, and 100 mL of a tetrahydrofuran / methanol mixture were mixed and reacted at 80 °C for 48 h. After the reaction, the organic solvent was removed by rotary evaporation. 1 mL of methanol was added to dissolve the CPs, and the mixture was transferred to a dialysis bag with a molecular weight of 2.5 kDa and dialyzed for 3 days. After further removal of the organic solvent by rotary evaporation, the AIE-type cationic conjugated polymer AIE-CPs (in structural formula I, the acceptor fluorescent group R is...) was obtained. ).

[0102] The structural formula of 4,7-bis(5-(4,4,5,5-tetramethyl-1,3,2-dioxoboronyl-2-yl)thiophene-2-yl)benzo[c]bis([1,2,5]thiadiazole) is as follows:

[0103] ;

[0104] The synthetic route for 4,7-bis(5-(4,4,5,5-tetramethyl-1,3,2-dioxoboronyl-2-yl)thiophene-2-yl)benzo[c]bis([1,2,5]thiadiazole) is as follows:

[0105] ;

[0106] The 1H NMR spectrum of the AIE-type cationic conjugated polymer obtained in this embodiment is compared with the characterization results in Example 1. Figure 3 The shown proton NMR spectrum and Figure 4 The fluorescence intensity characterization diagram shown is similar and will not be repeated here.

[0107] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0108] For the sake of simplicity, the method embodiments are described as a series of actions. However, those skilled in the art should understand that the present invention is not limited to the described order of actions, as some steps can be performed in other orders or simultaneously according to the present invention. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and components involved are not necessarily essential to the present invention.

[0109] The above provides a detailed description of the AIE-type cationic conjugated polymer, its preparation method, and its applications. Specific examples have been used to illustrate the principles and implementation methods of the invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the invention. At the same time, those skilled in the art will recognize that, based on the ideas of the invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the invention.

Claims

1. An AIE-type cationic conjugated polymer, characterized in that, The AIE-type cationic conjugated polymer has a structural formula shown in Formula I: Formula I R is selected from any one of the following structures: 。 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, mixing [1,1-bis(4-bromophenyl)-2,2-bis(4-hydroxyphenyl)] ethylene, cesium carbonate and anhydrous acetone solution to form a first solution; mixing 3-chloro-1-(N,N-dimethyl) propylamine and N,N-dimethylformamide solution to form a second solution; Step 2, mixing the first solution and the second solution, and placing them at 45-120 DEG C for 6-12 hours, and then purifying the obtained product by first separation to obtain a first monomer; Step 3, mixing the first monomer, acceptor fluorophore R precursor and toluene solution to form a third solution; Potassium carbonate solution is added to ultrapure water to form a fourth solution; Step 4, mixing the third solution and the fourth solution, degassing treatment, then adding tetrakis(triphenylphosphine)palladium, and placing them at 60-120 DEG C for 6-48 hours, and then purifying the obtained product by second separation to obtain a precursor polymer CPs; Step 5, mixing the precursor polymer CPs, (3-bromopropyl) trimethylammonium bromide and tetrahydrofuran / methanol mixed solution, and placing them at 45-80 DEG C for 12-48 hours, and then purifying the obtained product by third separation to obtain the AIE-type cationic conjugated polymer AIE-CPs; The acceptor fluorophore R precursor comprises any one of the following structures: 。 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 use amount ratio of [1,1-bis(4-bromophenyl)-2,2-bis(4-hydroxyphenyl)] ethylene, cesium carbonate and anhydrous acetone solution is (0.1-1.0) g:(0.1-1.2) g:(25-100) mL; and / or The use amount ratio of 3-chloro-1-(N,N-dimethyl) propylamine and N,N-dimethylformamide is (0.1-1.2) 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 first separation and purification comprises: The obtained product is dried by anhydrous sodium sulfate, and then organic solvent is removed by rotary evaporation; then saturated sodium chloride aqueous solution and dichloromethane are added for organic phase extraction; The obtained organic phase is dried by anhydrous sodium sulfate, and then organic solvent is removed by rotary evaporation; then the purified first monomer is obtained by column chromatography elution.

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 3, the use amount ratio of the first monomer, the acceptor fluorophore R precursor and the toluene solution is (0.1-1.0) g:(0.05-0.5) g:(10-100) mL; and / or The use amount ratio of potassium carbonate and ultrapure water is (0.5-5.0) g:(1-10) mL.

6. The method for preparing the AIE-type cationic conjugated polymer according to claim 2, characterized in that, In step 4, the second separation and purification comprises: The obtained product is dried by anhydrous sodium sulfate, and then organic solvent is removed by rotary evaporation; then water and dichloromethane are added for organic phase extraction; The obtained organic phase is dried by anhydrous sodium sulfate, and then organic solvent is removed by rotary evaporation to obtain the purified precursor polymer CPs.

7. The method for preparing the AIE-type cationic conjugated polymer according to claim 2, characterized in that, In step 5, the tetrahydrofuran / methanol mixed solution is formed by mixing tetrahydrofuran and methanol in equal volume; and / or The precursor polymer CPs, (3-bromopropyl) trimethylammonium bromide and tetrahydrofuran / methanol mixed solution are used in a ratio of (0.01-0.1) g:(0.05-1.0) g:(10-100) mL.

8. The method for preparing the AIE-type cationic conjugated polymer according to claim 2, characterized in that, In step 5, the third separation and purification comprises: After removing tetrahydrofuran and methanol in the obtained product by using a rotary evaporator, methanol solution is added for dissolution; The obtained mixture is dialyzed for 1-3 days, and the obtained solid is washed with dichloromethane for three times and dried to obtain the AIE-type cationic conjugated polymer AIE-CPs.

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

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