CN114989093A - Preparation and application of AIE fluorescent material - Google Patents

Abstract

The invention belongs to the field of fluorescent small molecule self-assembly, and specifically discloses the synthesis of three kinds of fluorescent materials capable of self-assembly, the preparation method of self-assembly and its application in cation detection. The three fluorescent materials are: (Z)‑5‑(4‑dimethylaminobenzylidene)‑2‑(2‑cyanoethyl)‑3‑methylimidazolidinone, (Z)‑5‑ (3-Dimethylaminobenzylidene)-2-(2-cyanoethyl)-3-methylimidazolidinone, (Z)-5-(4-hydroxy-3,5-difluorobenzylidene methyl)-2-n-hexyl-3-methylimidazolidinone. All three compounds can self-assemble into fibrous structures with fluorescent properties and uniform structure in methanol and water solvent systems. Among them: (Z)‑5‑(4‑dimethylaminobenzylidene)‑2‑(2‑cyanoethyl)‑3‑methylimidazolidinone can identify copper ions and mercury ions in pure water , and can quantitatively detect mercury ions.

Description

Preparation and Application of AIE Fluorescent Materials

technical field

The invention belongs to the field of fluorescent small molecule self-assembly, and relates to the synthesis of three kinds of fluorescent materials capable of self-assembly, the preparation method of self-assembly and its application in cation detection and cytotoxicity.

Background technique

Luminescent materials with tunable luminescent properties are a hot spot of attention. Traditional organic fluorescent molecules can only have fluorescent properties in dilute solutions due to aggregation-induced quenching (ACQ), which greatly limits their use in solid luminescent materials. Applications. To overcome this problem, many efforts have been made, such as adding branched or macrocycles to polymers with a higher glass transition temperature, or blending them with polymers with a higher glass transition temperature, but the results have been inconsistent. not ideal. The phenomenon of aggregation-induced emission (AIE) discovered by Academician Tang Benzhong in 2001 provides another way to solve this problem. They developed a new molecule that fluoresces weakly in solution but emits intense light when aggregated. This unusual fluorescence behavior is due to confinement of molecular intrarotation, aggregation-induced planarization, and in some cases the formation of J-aggregates. After years of research, many amazing molecules with AIE effects have been designed.

Molecular self-assembly is the directed association of molecules into nano- or micro-structures through non-covalent interactions. AIE molecules have the advantages of high solid-state fluorescence efficiency and variable emission color, and are ideal building blocks for the construction of luminescent micro/nanostructures. Due to its unique properties, AIE molecules can be designed as a new type of functional materials, which have a wide range of applications in biology, environment, materials, pharmaceuticals, agriculture and other fields. However, classical AIE molecules are difficult to spontaneously assemble into ordered assemblies due to their non-planar topology.

SUMMARY OF THE INVENTION

The green fluorescent protein chromophore (HBI) derivatives synthesized by the applicant's project also have the AIE effect, and the green fluorescent protein chromophore derivatives can form nanomaterials with uniform structure through self-assembly under certain conditions. Since HBI is derived from the chromophore of green fluorescent protein, the self-assembly of its derivatives has better biocompatibility and lower cytotoxicity, which makes it have better applications in the field of biomedicine. In addition, since molecular self-assembly is mainly formed through intermolecular hydrogen bonds, π–π stacking and other non-covalent bonds, some heavy metal ions can inhibit molecular self-assembly through the competition of hydrogen bonds, resulting in fluorescence changes or by ions disintegrating molecular self-assembly. Fluorescence is quenched, enabling detection of ions. Based on this principle, heavy metal ions can be detected in pure aqueous systems or in cells.

Based on the above technical principles, the present invention has four purposes: (1) to provide several HBI derivatives capable of forming nanomaterials with fluorescent properties through self-assembly; (2) to provide the above-mentioned nanomaterials capable of forming fluorescent properties through self-assembly (3) Provide a method for the self-assembly of the above-mentioned HBI derivative to form a nanomaterial; (4) Provide the above-mentioned method for detecting mercury ions and/or copper ions by the above-mentioned nanomaterials with fluorescent properties.

In order to achieve the above object, the present invention adopts the following technical solutions:

1. A molecular probe for detecting heavy metal ions (mercury and/or copper ions)

The molecular probe is self-assembled from HBI derivatives in a solvent system to form a uniform nanofibrous structure. The molecular probe is capable of recognizing mercury ions and/or copper ions.

The structural formula of the HBI derivative is shown below:

Its chemical names are:

(Z)-5-(4-Dimethylaminobenzylidene)-2-(2-cyanoethyl)-3-methylimidazolidinone, marked as XSG;

(Z)-5-(3-dimethylaminobenzylidene)-2-(2-cyanoethyl)-3-methylimidazolidinone, marked as FSG;

(Z)-5-(4-Hydroxy-3,5-difluorobenzylidene)-2-n-hexyl-3-methylimidazolidinone, labeled XWC.

The molecular probe is formed by self-assembly of XSG in a solvent system, the solvent system is a pure water system and a methanol/water system, and the methanol/water system in the methanol/water system has a volume ratio of 0-20%, for example, it can be the volume of methanol A methanol/water system with a ratio of 20%; preferably, the solvent system is a pure water phase, which contains no organic solvent.

The molecular probe is formed by self-assembly of FSG in a solvent system, and the solvent system is methanol/water system, tetrahydrofuran/water system, 1,1,1,3,3,3-hexafluoro-2-propanol/ Water system or dimethyl sulfoxide/water system, wherein the volume ratio of methanol in the solvent system is 0 to 20%, the volume ratio of tetrahydrofuran is 0 to 10%, and the volume ratio of 1,1,1,3,3,3-hexafluoro-2- The volume ratio of propanol is 0-10%, and the volume ratio of dimethyl sulfoxide is 0-5%; preferably, in the solvent system, the volume ratio of methanol is 10%-20%, and the volume ratio of tetrahydrofuran is 5%-10%, The volume ratio of 1,1,1,3,3,3-hexafluoro-2-propanol is 5% to 10%, and the volume ratio of dimethyl sulfoxide is 1% to 5%.

The molecular probe is formed by self-assembly of XWC in a solvent system, and the solvent system is a methanol/water system, wherein the methanol volume ratio in the solvent system is 0-20%; preferably, the methanol volume ratio in the solvent system is 10% to 20%.

2. Synthesis of HBI derivatives XSG, FSG and XWC

The synthetic route of HBI derivatives is shown below:

Wherein: rt in the route refers to room temperature; R ₁ is 4-N, N-dimethyl 4-N(Me) ₂ , 3-N, N-dimethyl 3-N(Me) ₂ or 3,5-dimethy Fluoro-4-hydroxy 3,5-F,4-OH; R ₂ is propionitrile or n-hexane.

3. The method of self-assembly of HBI derivatives to form nanomaterials

The HBI derivatives are dissolved in the solvent system, and after mixing, stand still to obtain HBI derivatives (XSG, FSG and XWC) self-assembled fluorescent materials, that is, molecular probes for detecting heavy metal ions are obtained.

Fourth, the application of the above molecular probe in the preparation and detection of heavy metal ion probes.

The molecular probe can identify mercury ions and/or copper ions, the concentration of copper ions in the solution to be tested is 0-1 mmol/L, and the concentration of mercury ions is 0-1 mmol/L.

In one aspect, the molecular probe can be assembled by an ion-suppressed probe, resulting in a change in its fluorescence to detect ions. Preferably, the molecular probe is formed by self-assembly of XSG in a solvent system.

The molecular probe, on the other hand, can detect ions by ionically disrupting the assembly, resulting in a change in its fluorescence (quenching). Preferably, the molecular probe is formed by self-assembly of XSG in a solvent system.

Preferably, the application of the above molecular probe in detecting heavy metal ion probes in the preparation of a pure water phase system, the molecular probe is formed by self-assembly of XSG in a solvent system, and the solvent system is a pure water phase, which does not contain organic solvent.

Preferably, the application of the above molecular probe in the qualitative and/or quantitative detection of mercury ion probes in the preparation of a pure water phase system, the molecular probe is formed by self-assembly of XSG in a solvent system, and the solvent system is pure water phase, which does not contain organic solvents.

Further, the concentration of copper ions in the solution to be tested is 0.01-0.1 mmol/L, and the concentration of mercury ions is 0.01-0.1 mmol/L.

It should be noted that: "the solvent system is pure water phase, which does not contain organic solvent" as used herein means that the content of organic solvent in the system is extremely small, the proportion of which is less than 0.1% in the solvent system, which can be ignored.

Compared with the prior art, the present invention has the following advantages and beneficial effects:

1. In the prior art, it is difficult to detect cations in pure water by using the mechanism of complexation. In the present invention, the XSG molecular probe can be used to realize the detection of cations in a 100% aqueous solvent system.

2. Mercury ions can inhibit the assembly of HBI derivatives (XSG, FSG, XWC), enabling naked vision detection of mercury ions.

3. The present invention can utilize the XSG molecular probe to realize the quantitative detection of Hg ²⁺ in the pure water phase solvent system.

Description of drawings

Figure 1: Fluorescence microscopy images of 1 mg/mL XSG self-assembled in different solvents (a, c, d, e) and 0.17 mg/mL XSG self-assembled in ultrapure water; a is v/v 20% methanol/water, b is 100% water, c is 10% v/v THF/water, d is 10% v/v HFP/water, e is 5% v/v DMSO/water.

Figure 2: Fluorescence microscope images (a-c) and scanning electron microscope images (d-g) of the self-assembly process of XSG in 1 mg/mL, 20% methanol in water (v/v).

Figure 3: Fluorescence microscopy images of 1 mg/mL FSG self-assembly in different solvents (a-e); a is v/v 20% methanol/water, b is v/v 10% THF/water, c is v /v is 10% isopropanol/water, d is 10% v/v HFP/water, e is 5% v/v DMSO/water.

Figure 4: Fluorescence microscope images (a-c) and scanning electron microscope images (d-g) of the self-assembly process of FSG in 1 mg/mL, 20% methanol in water (v/v).

Figure 5: Fluorescence microscopy images of 1 mg/mL XWC self-assembly in different solvents (a-d): a is v/v 20% methanol/water, b is v/v 20% acetonitrile/water, c is v /v is 5% DMSO/water, d is v/v 5% DMF/water.

Figure 6: Fluorescence microscopy images (a) and SEM images (b, c) of XWC self-assembly in 1 mg/mL, 20% methanol in water (v/v).

Figure 7: Molecular fluorescence spectra of XSG, FSG, XWC in 1 mg/mL, 20% methanol in water (v/v).

Figure 8: 0.1 mg/mL XSG in pure water blank (a) and 1.6 mmol/L Cu ²⁺ (b), Hg ²⁺ (c), Na ⁺ (d), Ag ⁺ (e), Ca Fluorescence microscopy images (TRITC mode test) of self-assembly in aqueous solutions of ²⁺ (f), K ⁺ (g), Mg ²⁺ (h), Zn ²⁺ (j).

Figure 9: After 0.1 mg/mL XSG formed self-assembly in pure water, its fluorescence spectrum was tested, and its assembled morphology was observed by fluorescence microscope; then 10 μL of mercury ions and copper ions were added to the assembled solution, respectively (The final concentration of both ions was 1 mmol/L), the fluorescence intensity of the XSG solution was tested after 3 hours (excitation wavelength was 509 nm, slit width was 5 nm-5 nm), and its assembly was observed by fluorescence microscopy (TRITC mode test) appearance.

Figure 10: Molecular fluorescence spectrum of 0.1 mg/mL XSG in pure aqueous solution when the mercury ^ion concentration ranges from 0.01 to 1 mmol/L (10a); Figure 10b is obtained by plotting the curve of , and the line graph on the right side of Figure 10b can be obtained by taking the fluorescence value at 533 nm in the figure, and its linear fitting pattern can be obtained.

Fig. 11: The graph of the cytotoxicity of XSG, FSG and XWC in human glioma cells at concentrations of 10 ^-5 , 10 ^-6 , and 10 ^-7 mol/L, respectively.

Detailed ways

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

Example 1: Preparation of HBI derivatives XSG, FSG and XWC

1. Synthesis of compound 2

Take a 500mL eggplant-shaped bottle, add 200mL ether, 32mL deionized water, 10g glycine methyl ester hydrochloride, then add 11g anhydrous potassium carbonate, stir for 10min, and then add 9.8g ethylacetimide hydrochloride to react for 10min. The aqueous phase and the organic phase were separated by a separating funnel, 200 mL of ether was added to the aqueous phase again, the reaction was continued for 10 min, and the organic phases were combined. Anhydrous magnesium sulfate was added to the organic phase, dried, filtered, and spin-dried to obtain product 2 as a light yellow liquid.

2. Preparation of XSG

Take a 50mL dry eggplant-shaped bottle, add 4-dimethylaminobenzaldehyde (1.49g, 10mmol) and 3-aminopropionitrile (77mg, 11mol), use 20mL of absolute ethanol as a solvent, and stir at room temperature for 12h under nitrogen atmosphere . The corresponding Schiff base was obtained after the solvent was spin-dried. Then, newly prepared compound 2 (1.25 g, 11 mmol) was added, and 20 mL of anhydrous ethanol was used as a solvent, and the mixture was stirred at room temperature for 12 h. After the reaction, spin dry the solvent, and separate and purify the final product XSG by column chromatography: (Z)-5-(4-dimethylaminobenzylidene)-2-(2-cyanoethyl)-3- Methylimidazolidinone.

HRMS: calculated for [M+H]: 283.15, measured: 283.1551; ¹ H NMR (400MHz, DMSO, 298K): δ(ppm): 8.07(d, J=8.8Hz, 2H), 6.91(s, 1H) ,6.76(d,J＝8.9Hz,2H),3.85(t,J＝6.5Hz,2H),3.01(s,6H),2.88(t,J＝6.5Hz,2H),2.39(s,3H) ; ¹³ C NMR (101MHz, DMSO, 298K): δ (ppm): 169.81, 159.45, 151.90, 134.44, 134.24, 127.75, 121.85, 119.17, 112.13, 40.07, 36.17, 17.58, 15.68.

3. Preparation of FSG

Take a 50 mL dry eggplant-shaped bottle, add 3-dimethylaminobenzaldehyde (1.49 g, 10 mmol) and 3-aminopropionitrile (77 mg, 11 mol), use 20 mL of anhydrous ethanol as a solvent, and stir at room temperature for 12 h under a nitrogen atmosphere . The corresponding Schiff base was obtained after the solvent was spin-dried. Then, newly prepared compound 2 (1.25 g, 11 mmol) was added, and 20 mL of anhydrous ethanol was used as a solvent, and the mixture was stirred at room temperature for 12 h. After the reaction, the solvent was spin-dried, and the final product FSG was obtained by separation and purification by column chromatography: (Z)-5-(3-dimethylaminobenzylidene)-2-(2-cyanoethyl)-3- Methylimidazolidinone.

HRMS: calculated for [M+H]: 283.15, measured: 283.1547; ¹ H NMR(400MHz, DMSO, 298K): δ(ppm): 7.62–7.56(m, 1H), 7.25(t, J=8.0Hz, 1H), 6.97(s, 1H), 6.82-6.78(m, 1H), 3.87(t, J=6.6Hz, 1H), 2.92(s, 1H), 2.42(s, 1H); ¹³ CNMR(101MHz, DMSO, 298K): δ(ppm): 170.15, 163.05, 150.97, 138.25, 134.77, 129.59, 127.36, 120.67, 119.11, 116.43, 114.94, 40.53, 36.28, 17.54, 15.95.

4. Preparation of XWC

Take a 50 mL dry eggplant-shaped bottle, add 3,5-fluoro, 4-hydroxybenzaldehyde (1.58 g, 10 mmol) and n-hexylamine (1.45 mL, 11 mol), use 20 mL of anhydrous ethanol as a solvent, under a nitrogen atmosphere at room temperature Stir for 12h. The corresponding Schiff base was obtained after the solvent was spin-dried. Then, newly prepared compound 2 (1.25 g, 11 mmol) was added, and 20 mL of anhydrous ethanol was used as a solvent, and the mixture was stirred at room temperature for 12 h. After the reaction, spin dry the solvent, and separate and purify by column chromatography to obtain the final product XWC: (Z)-5-(4-hydroxy-3,5-difluorobenzylidene)-2-n-hexyl-3-methyl imidazolidinone.

HRMS: calculated for [M+H]: 322.15, measured: 322.1524; ¹ H NMR(400MHz, DMSO, 298K): δ(ppm): 8.05(d, J=9.0Hz, 2H), 6.85(s, 1H) ,6.74(d,J=9.1Hz,2H),3.53(t,J=7.3Hz,2H),3.01(s,6H),2.33(s,3H),1.68–1.43(m,2H),1.26( m, 6H), 0.86 (t, J=6.8Hz, 3H); ¹³ C NMR (101MHz, DMSO, 298K): δ (ppm): 170.10, 164.48, 153.53, 151.13, 138.62, 136.15, 125.18, 123.38, 115.75 ,40.33,31.25,28.96,26.28,22.45,15.91,14.34.

Example 2: Preparation method of XSG, FSG, XWC self-assembled materials

1. XSG self-assembly

(1) The effect of solvent on the self-assembly of XSG

Five parts of 1 mg of XSG were accurately weighed, and four parts were dissolved in 200 μL of methanol, 100 μL of tetrahydrofuran (THF), and 100 μL of 1,1,1,3,3,3-hexafluoro-2-propanol (HFP), respectively. , 50 μL of dimethyl sulfoxide (DMSO), and then correspondingly added 800 μL, 900 μL, 900 μL, and 950 μL of ultrapure water. After mixing with a shaker, let stand for 2 hours to obtain the self-assembly of XSG. The self-assembled solution was placed on a glass plate, and after it was naturally dried, the self-assembly morphology of XSG in different solvent systems was tested by fluorescence microscopy, as shown in Figure 1(a, c-e): a methanol/water (v/v : 2/8), c THF/water (v/v: 1/9), dHFP/water (v/v: 1/9), e DMSO (v/v: 0.5/9.5). 1 part was dissolved in 6 mL of ultrapure water (heated in a water bath at 80 degrees Celsius for 1 hour), cooled to room temperature naturally and allowed to stand for 3 hours to obtain the self-assembly of XSG, and its self-assembly was tested by fluorescence microscopy, as shown in Figure 1(b) .

As shown in Figure 1, XSG can self-assemble into fibrous nanomaterials with uniform structure in methanol/water and pure water solvent systems, and both exhibit green fluorescence. In other solvent systems, the structure of self-assembly is more complex and disordered. Therefore, the suitable solvent system for the self-assembly of XSG is methanol/water or pure water.

(2) XSG assembly process in methanol and water mixed solvent

At room temperature, 1 mg of XSG was accurately weighed and dissolved in 200 μL of methanol solvent. After complete dissolution, 800 μL of ultrapure water was added, and the methanol/ultrapure aqueous solution containing XSG was mixed with a shaker. After 2 hours, the solution was transferred to the glass plate and the silicon wafer respectively, put into a freeze dryer to freeze-dry, and passed through a fluorescence microscope (sample on the glass plate) and a super-resolution cold field scanning electron microscope (sample on the silicon wafer). Test its appearance.

As shown in Figure 2, when water was added to the methanol solution containing XSG, due to the poor solubility of XSG in water, XSG immediately self-assembled to form fine fibrous spherical nanomaterials (Figure 2a, 2d). Then, the tiny fiber balls are intertwined into thicker rods (Fig. 2b and 2e), and finally assembled to form nanorod-like structures with uniform structure (Fig. 2c and Fig. 2f), and the cross-sectional view (Fig. Solid rod structure.

2. Self-assembly of FSG

(1) Effect of solvent on FSG self-assembly

Five parts of 1 mg of FSG were accurately weighed and dissolved in 200 μL of methanol, 100 μL of tetrahydrofuran (THF), 100 μL of isopropanol, and 100 μL of 1,1,1,3,3,3-hexafluoro-2-propanol. (HFP), 50 μL of dimethyl sulfoxide (DMSO), and then correspondingly added 800 μL, 900 μL, 900 μL, 900 μL, 950 μL of ultrapure water, shake well, and let stand for 2 hours to obtain the self-assembly of FSG , respectively transfer the solution containing the self-assembly onto the glass plate, and after it is naturally dried, test its self-assembly by fluorescence microscope, as shown in Figure 3(a-e): a methanol/water (v/v: 2/8 ), b THF/water (v/v: 1/9), c isopropanol/water (v/v: 1/9), dHFP/water (v/v: 1/9), e DMSO (v/ v: 0.5/9.5).

As shown in Figure 3, FSG cannot form nanomaterials with uniform structure through self-assembly in the isopropanol/water solvent system, and nanofibrous materials with green fluorescence properties can be formed in other solvent systems, and the fibers formed by FSG are relatively small. Fibers formed by XSG are finer.

(2) FSG assembly process in methanol and water mixed solvent

At room temperature, accurately weigh 1 mg of FSG and dissolve it into 200 μL of methanol solvent. After it is completely dissolved, add 800 μL of ultrapure water, and use a shaker to mix the methanol/ultrapure aqueous solution containing FSG, and let stand for 0min and 30min respectively After 2 hours, the solution was transferred to the glass plate and the silicon wafer respectively, put into a freeze dryer to freeze-dry, and passed through a fluorescence microscope (sample on the glass plate) and a super-resolution cold field scanning electron microscope (sample on the silicon wafer). Test its shape.

As shown in Fig. 4, when water was added to the methanol solution containing FSG, due to the poor solubility of FSG in water, FSG immediately self-assembled to form a finer fibrous spherical nanomaterial than XSG (Fig. 4a, 4d), Over time, the tiny fiber balls intertwined into thicker rods (Fig. 4b and Fig. 4e), and finally assembled to form a uniform nanofibrous structure (Fig. 4c and Fig. 4f). 4g) indicates that it is a solid rod-like structure.

3. Self-assembly of XWC

(1) The effect of solvent on the self-assembly of XWC

Accurately weigh four parts of 1 mg of XWC, dissolve them in 200 μL of methanol, 200 μL of acetonitrile, 50 μL of DMSO, and 50 μL of N,N-dimethylformamide (DMF), respectively, and then add 800 μL, 800 μL, 950 μL, 950 μL of ultrapure water, mixed with a shaker, and allowed to stand for 6 hours to obtain the self-assembly of XWC. The solution containing the self-assembly was spotted on a glass plate, and after it was naturally dried, the XWC was tested by a fluorescence microscope. The self-assembly morphologies in different solvent systems are shown in Fig. 5(a-d): a methanol/water (v/v: 2/8), b acetonitrile/water (v/v: 2/8), c DMSO/water ( v/v: 0.9/9.5), dDMF/water (v/v: 0.5/9.5).

As shown in Figure 5, the solvent has a great influence on the assembly of XWC. In the mixed system of methanol and water, XWC can form a nanorod-like structure with uniform structure, and in the mixed solvent system of acetonitrile and water, it forms a wide flat rod-like structure. In the more polar DMSO and DMF systems, very fine filamentous structures are formed.

(2) Study on the assembly morphology of XWC in methanol and water mixed solvent system

At room temperature, 1 mg of XWC was accurately weighed and dissolved in 200 μL of methanol solvent. After it was completely dissolved, 800 μL of ultrapure water was added, mixed with a shaker, and after standing for 6 hours, the self-assembly of XWC was obtained. The solution of the assembly was spotted on a glass plate, placed in a freeze dryer for lyophilization, and its self-assembly was tested by fluorescence microscopy, as shown in Figure 6a. The solution containing the self-assembly was spotted on a silicon wafer, put into a freeze dryer to freeze dry, and its morphology was tested by ultra-high resolution cold field scanning electron microscopy, as shown in Figure 6(b-c).

As shown in Figure 6a, the self-assembly of XWC is also a rod-like structure, and its rod-like structure is straighter than that of XSG and FSG, and its cross-section (Figure 6c) is also a solid rod-like structure.

4. XSG, FSG, XWC fluorescence properties

Accurately weigh 1 mg of XSG, FSG, and XWC, respectively, and dissolve them in 200 μL of methanol solvent. After they are completely dissolved, add 800 μL of ultrapure water respectively. After mixing with a shaker, measure their fluorescence emission spectra. Then, after standing for 6 hours, after the self-assembly was completed, the fluorescence emission spectra were tested respectively. The excitation wavelength of the test XSG is 516nm, and the slit width is 5nm-5nm, as shown in Figure 7a; the excitation wavelength of the test FSG is 445nm, and the slit width is 5nm-5nm, as shown in Figure 7b; the excitation wavelength of the test XWC is 415nm, and the slit The width is 5nm-5nm, as shown in Figure 7c.

As shown in Figure 7a, the fluorescence intensity of XSG after assembly was about 7.7 times higher than that before assembly, and the optimal emission wavelength of fluorescence occurred red-shifted from 549 nm before assembly to 593 nm after assembly; The fluorescence intensity was enhanced by about 250 times, and the optimal emission wavelength of fluorescence was blue-shifted from 540 nm before assembly to 536 nm after assembly; Figure 7c shows that three fluorescence emission peaks appeared after XWC assembly, and the intensity of the highest fluorescence emission peak was enhanced by about 36 times, the corresponding fluorescence emission wavelength red-shifted from 522 nm before assembly to 549 nm after assembly. In addition, XWC also appeared fluorescence emission peaks at 482 and 518 nm.

Example 3: Application of XSG for the detection of cations

(1) The response of XSG to various cations

Prepare 160mmol/L Cu ²⁺ , Hg ²⁺ , Na ⁺ , Ag ⁺ , Ca ²⁺ , K ⁺ , Mg ²⁺ , Zn ²⁺ aqueous solution respectively, the steps are: respectively accurately weigh a certain amount of copper nitrate trihydrate , mercuric perchlorate trihydrate, sodium chloride, silver nitrate, anhydrous calcium chloride, potassium chloride, anhydrous magnesium sulfate and zinc chloride were added to a 10mL EP tube, and dissolved in appropriate amount of water with a pipette. Ultrasound for 0.5 min.

Accurately weigh two parts of 3 mg of XSG into the EP tube, add 30 mL of ultrapure water, heat in a water bath at 80°C for one hour to form a hot solution, pipette 8 parts of 3 mL of 0.1 mg/mL XSG aqueous solution into the EP tube, and then separately Add 30 μL of an aqueous solution containing Cu ²⁺ , Hg ²⁺ , Na ⁺ , Ag ⁺ , Ca ²⁺ , K ⁺ , Mg ²⁺ , Zn ²⁺ to make the final concentration 1.6 mmol/L, and let stand for 6 hours. The solution was taken onto a glass plate, and the effect of different metal ions on the self-assembly of XSG was observed by fluorescence microscope. Figure 8, pure water blank (8a), Cu ²⁺ (8b), Hg ²⁺ (8c), Na ⁺ (8d), Ag ⁺ (8e), Ca ²⁺ (8f), K ⁺ (8g), Mg ²⁺ (8h), Zn ²⁺ (8j).

As shown in Figure 8, Cu ²⁺ ions and Hg ²⁺ ions can inhibit XSG self-assembly, while other metal ions have no effect on XSG self-assembly. It shows that Cu ²⁺ ions and Hg ²⁺ ions can be detected by the self-assembly of XSG. Similarly, the self-assembly of FSG and XWC in the solvent system can be used to detect Cu ²⁺ ions and Hg ²⁺ ions.

(2) The response of XSG assembly to Cu ²⁺ ions and Hg ²⁺ ions, respectively

Accurately weigh 2 mg of XSG into an EP tube, add 20 mL of ultrapure water, heat in a water bath at 80°C for one hour to form a hot solution, and pipette 3 mL of 0.1 mg/mL XSG aqueous solution into a cuvette for self-assembly After 3 hours, after the XSG assembly was completed, its fluorescence spectrum was tested, and part of the solution was transferred to a glass plate. After it was naturally dried, the assembled morphology was observed by a fluorescence microscope; then 18.7 was added to the assembled solution system. μL of aqueous solution containing Hg ²⁺ and Cu ²⁺ to make the final concentration 1 mmol/L. After standing for 3 hours, the fluorescence spectrum was tested, and part of the solution was transferred to a glass plate, and after it was naturally dried, the assembled morphology was observed by a fluorescence microscope.

As shown in Figure 9, the self-assembly of XSG in pure water phase has a maximum emission fluorescence spectrum around 600 nm (Figure 9d), Figure 9a shows the morphology of XSG self-assembly in pure water phase, Figure 9c shows the addition of Cu The morphology of the XSG self-assembly of ²⁺ , indicating that Cu ²⁺ can partially disintegrate the XSG self-assembly (Fig. 9c), resulting in a decrease in its fluorescence intensity (Fig. 9d). Figure 9b shows the morphology of the self-assembly of XSG added with Hg ²⁺ , indicating that Hg ²⁺ can completely disintegrate the XSG self-assembly (Figure 9b), resulting in complete quenching of its fluorescence intensity (Figure 9d). Cu ²⁺ and Hg ^{2+ were} detected. Similarly, Cu ²⁺ ions and Hg ²⁺ ions can be detected after FSG and XWC are used to form assemblies in a solvent system.

(3) Quantitative detection of Hg ²⁺ by XSG

Accurately weigh 2 mg of XSG into an EP tube, add 20 mL of ultrapure water, heat in a water bath at 80°C for one hour to form a hot solution, and pipette 3 mL of 0.1 mg/mL XSG aqueous solution into a cuvette for self-assembly After 3 hours, after the XSG was assembled, its fluorescence spectrum was tested, and then 10 μL of Hg ²⁺ aqueous solutions with different concentrations were added to ensure that the final concentration was 0.01-1 mmol/L. After standing for 3 hours, the fluorescence intensity was measured, and Figure 10a was obtained. , and plot the fluorescence intensity corresponding to the concentration of 0.01-0.1 mmol/L from Fig. 10a to obtain Fig. 10b.

Figure 10a shows that the addition of Hg ²⁺ significantly reduces the fluorescence intensity of XSG self-assembly, and its fluorescence maximum emission peak shifts from 600nm to 540nm; Figure 10b shows that with the increase of Hg ²⁺ concentration, the fluorescence of XSG self-assembly gradually increases weaken. The Hg ²⁺ concentration and the fluorescence value were linearly fitted at 533 nm in the range of 0.01～0.1 mmol/L, and it was found that there was a certain linear relationship between the two. The Hg ²⁺ concentration could be quantitatively detected by this method. It also shows that the use of XSG self-assembly can realize the detection of Cu ²⁺ and Hg ²⁺ in pure water phase ^; and can realize naked vision detection and quantitative detection of Hg ²⁺ in pure water phase.

Example 4: MTT test of XSG, FSG, XWC

U87 (human glioma cell line) cells were cultured at 30,000 cells/well in a 24-well plate, and the medium was DMEM, 10% fetal bovine serum (FBS), 0.1% double antibody (penicillin, streptomycin) , 5% carbon dioxide, incubated at 37 °C for 24 hours, and then added 10 μL of DMSO solutions of different concentrations of XSG, FSG, XWC, respectively, the final concentrations of XSG, FSG, XWC were 0.1 μmol/L, 1 μmol/L, 10 μmol/L, incubate for 24 hours, take 50 μL of CCK-8 kit, add the aforementioned U87 cells to the aforementioned U87 cells and incubate for 2 hours at 37°C, and test the absorbance at 450 nm on a multi-labeled microplate.

Figure 11 shows that in the concentration range of 0.1-10 μmol/L, the cytotoxicity of XSG, FSG and XWC to U87 cells is very low.

Claims (10)

1. An AIE molecule, wherein said AIE molecule has the structural formula:

2. the AIE molecule of claim 1, wherein the AIE molecule is synthesized by the following route:

wherein: r ₁ Is 4-N, N-dimethyl-4-N (Me) ₂ 3-N, N-dimethyl-3-N (Me) ₂ Or 3, 5-difluoro-4-hydroxy 3,5-F, 4-OH; r ₂ Is propionitrile or n-hexane.

3. A molecular probe for detecting heavy metal ions, wherein the molecular probe is formed by the AIE molecule of claim 1 or 2 self-assembling in a solvent system to form a uniform nano-fiber-like structure, and the molecular probe can recognize mercury ions and/or copper ions.

4. The molecular probe for detecting heavy metal ions according to claim 3, wherein the molecular probe is formed by self-assembly of XSG in a solvent system, the solvent system is a pure water system and a methanol/water system, and the volume ratio of methanol in the methanol/water system is 0-20%;

the molecular probe is formed by self-assembling FSG in a solvent system, wherein the solvent system is a methanol/water system, a tetrahydrofuran/water system, a 1,1,1,3,3, 3-hexafluoro-2-propanol/water system or a dimethyl sulfoxide/water system, the volume ratio of methanol in the solvent system is 0-20%, the volume ratio of tetrahydrofuran is 0-10%, the volume ratio of 1,1,1,3,3, 3-hexafluoro-2-propanol is 0-10%, and the volume ratio of dimethyl sulfoxide is 0-5%;

the molecular probe is formed by self-assembly of XWC in a solvent system, wherein the solvent system is a methanol/water system, and the volume ratio of methanol in the solvent system is 0-20%.

5. The molecular probe for detecting heavy metal ions according to claim 4, wherein the molecular probe is formed by self-assembly of XSG in a solvent system, the solvent system is a pure water system and a methanol/water system, and the volume ratio of methanol in the methanol/water system is 0-20%;

the molecular probe is formed by self-assembly of FSG in a solvent system, wherein the solvent system is a methanol/water system, a tetrahydrofuran/water system, a 1,1,1,3,3, 3-hexafluoro-2-propanol/water system or a dimethyl sulfoxide/water system, wherein the volume ratio of methanol in the solvent system is 10-20%, the volume ratio of tetrahydrofuran is 5-10%, the volume ratio of 1,1,1,3,3, 3-hexafluoro-2-propanol is 5-10%, and the volume ratio of dimethyl sulfoxide is 1-5%;

the molecular probe is formed by self-assembly of XWC in a solvent system, wherein the solvent system is a methanol/water system, and the volume ratio of methanol in the solvent system is 10-20%.

6. Use of the molecular probe for detecting heavy metal ions according to any one of claims 3 to 5 in the preparation of a probe for detecting heavy metal ions.

7. The use according to claim 6, wherein the molecular probe is an ion detectable by an ion-inhibiting probe assembly causing a change in its fluorescence.

8. The use according to claim 6, wherein the molecular probe detects ions by ion-disruption of the assembly, resulting in a change in fluorescence thereof.

9. Use of a molecular probe for detecting heavy metal ions according to any one of claims 3 to 5 in the preparation of a heavy metal ion detection probe in a pure water phase system, wherein the molecular probe is formed by self-assembly of XSG in a solvent system.

10. The use of the molecular probe for detecting heavy metal ions according to any one of claims 3 to 5 for qualitatively and/or quantitatively detecting mercury ions in the preparation of a pure water phase system, wherein the molecular probe is formed by self-assembly of XSG in a solvent system.

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