Alkyl pyridinium type aggregation-induced emission compound as well as preparation method and application thereof

Abstract

The invention discloses an alkyl pyridinium type aggregation-induced emission compound as well as a preparation method and application thereof, the molecular structural formula of the alkyl pyridinium type aggregation-induced emission compound is as follows: # imgabs0 #, the preparation method comprises the following steps: stirring a raw material D, 1, 4-dimethyl pyridine-1-iodide, absolute ethyl alcohol and piperidine, and performing reflux overnight; and cooling the reaction mixture, concentrating under reduced pressure, and eluting and purifying a crude product to obtain the alkyl pyridinium type aggregation-induced emission compound. The alkyl pyridinium type aggregation-induced emission compound provided by the invention can efficiently kill gram-positive bacteria and gram-negative bacteria at the same time.

Description

Technical Field

[0001] The present invention relates to the technical field of multifunctional organic small molecule synthesis, and in particular to an alkyl pyridinium salt type aggregation-induced emission compound and a preparation method and application thereof. Background Art

[0002] Bacterial infectious diseases pose a huge threat to human health. The use of broad-spectrum antibiotics has led to the development and spread of bacterial resistance, which has seriously hindered the fight against bacterial infections. Photodynamic therapy (PDT) is considered a potential means to eliminate pathogens because it is not easy to cause drug resistance. Compared with antibiotics with specific targets, under light irradiation, the cellular reactive oxygen species (ROS) produced will further damage the internal or external structure of bacteria, making it difficult for bacteria to develop resistance to PDT. It does not require photosensitizers to penetrate the bacterial cell membrane and enter the interior of the bacteria, so it has a different bactericidal mechanism from traditional antibiotics. At the same time, photodynamic antibacterial is an oxidative damage mechanism based on the synergistic action of three factors: light, photosensitizer, and oxygen, so it will not cause drug resistance due to factors such as single medication, photosensitizer concentration, and insufficient exposure time.

[0003] Currently, most photosensitizers (PSs) show obvious antibacterial effects on Gram-positive bacteria, but lack photosensitizers that can kill Gram-negative bacteria. This may be because the outer layer of Gram-negative bacteria is mainly composed of a thin peptidoglycan layer (-8nm) and an outer membrane strain composed of lipids and lipopolysaccharides, which makes it difficult for photosensitizers to bind to Gram-negative bacteria and the antibacterial effect is unsatisfactory. Summary of the invention

[0004] The object of the present invention is to provide an alkylpyridinium salt type aggregation-induced luminescence compound and a preparation method and application thereof, which can kill Gram-positive bacteria and Gram-negative bacteria through photodynamic action.

[0005] In one aspect of the present invention, the present invention provides an alkyl pyridinium salt type aggregation-induced emission compound. According to an embodiment of the present invention, the molecular structure of the alkyl pyridinium salt type aggregation-induced emission compound is as follows:

[0006]

[0007] In addition, the alkylpyridinium salt type aggregation-induced emission compound according to the above embodiment of the present invention may also have the following additional technical features:

[0008] In some embodiments of the present invention, the alkylpyridinium salt-type aggregation-induced emission compound has near-infrared fluorescence emission.

[0009] In another aspect of the present invention, the present invention provides a method for preparing an alkyl pyridinium salt type aggregation-induced emission compound. According to an embodiment of the present invention, the method comprises the following steps: stirring and refluxing the raw material D and 1,4-dimethylpyridine-1-iodide, anhydrous ethanol, and piperidine overnight, cooling the reaction mixture, concentrating under reduced pressure, and eluting and purifying the crude product to obtain the alkyl pyridinium salt type aggregation-induced emission compound;

[0010] Wherein, the structural formula of the raw material D is as follows:

[0011]

[0012] In addition, the method for preparing an alkylpyridinium salt type aggregation-induced emission compound according to the above embodiment of the present invention may also have the following additional technical features:

[0013] In some embodiments of the present invention, the molar ratio of the raw material D to 1,4-dimethylpyridine-1-iodide is 1:1-1:2

[0014] In some embodiments of the present invention, the preparation method of the raw material D comprises the following steps: mixing the raw material C, 1-bromododecane, KI and K2CO3 with acetonitrile under nitrogen, stirring and reflux overnight, cooling to room temperature, extracting the reaction mixture with water and dichloromethane, and then drying and concentrating the crude product by silica gel elution chromatography with a mixture of petroleum ether and ethyl acetate to obtain the raw material D;

[0015] Wherein, the structural formula of the raw material C is as follows:

[0016]

[0017] In some embodiments of the present invention, the preparation method of the raw material C comprises the following steps: adding the raw material B, 4-formylphenylboronic acid, Pd(dppf)Cl2 and K2CO3 to an anhydrous toluene / methanol solution under nitrogen, stirring overnight at 90-110°C, cooling to room temperature, extracting the solution with water and dichloromethane, drying and concentrating, and purifying the crude product by silica gel elution chromatography with a mixture of petroleum ether and dichloromethane to obtain the raw material C;

[0018] Wherein, the structural formula of the raw material B is as follows:

[0019]

[0020] In some embodiments of the present invention, the preparation method of the raw material B comprises the following steps: dissolving A in chloroform under ice bath conditions, adding a mixed solution of dichloromethane and boron tribromide dropwise to the mixture, and then reacting at room temperature for 16-18 hours, adding methanol dropwise to quench excess boron tribromide, cooling to room temperature, extracting the reaction mixture with ethyl acetate, washing the organic layer with saturated sodium bicarbonate and water, drying and concentrating, and purifying the crude product by column chromatography with a mixed solution of petroleum ether and ethyl acetate to obtain raw material B;

[0021] Wherein, the structural formula of the raw material A is as follows:

[0022]

[0023] In another aspect of the present invention, the present invention provides an application of an alkylpyridinium salt type aggregation-induced emission compound. According to an embodiment of the present invention, under light conditions, the alkylpyridinium salt type aggregation-induced emission compound is used to generate active oxygen and singlet oxygen.

[0024] In addition, the use of an alkylpyridinium salt type aggregation-induced emission compound according to the above embodiment of the present invention may also have the following additional technical features:

[0025] In some embodiments of the present invention, the alkyl pyridinium salt type aggregation-induced emission compound is used to prepare a fluorescent probe photosensitizer for photodynamic therapy.

[0026] In another aspect of the present invention, the present invention provides an application of an alkylpyridinium salt type aggregation-induced luminescence compound. According to an embodiment of the present invention, the alkylpyridinium salt type aggregation-induced luminescence compound kills Gram-positive bacteria and Gram-negative bacteria through photodynamic action.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] (1) Alkylpyridinium salt-type aggregation-induced emission compounds have a strong push-pull electron effect and a large Stokes shift, which makes the absorption and emission wavelengths of the molecules redder and have near-infrared fluorescence emission. The push-pull electron structure can promote intersystem crossing, making it easier for energy to reach the triplet state, converting the oxygen around the fluorescent probe photosensitizer into reactive oxygen. Reactive oxygen can cause the death of bacteria, thereby achieving photodynamic killing.

[0029] (2) The pyridinium salt in the molecular structure of the alkylpyridinium salt-type aggregation-induced emission compound carries a positive charge, and the bacterial surface is negatively charged. Due to the electrostatic interaction between the positive and negative charges, the positively charged aggregation-induced emission molecules are easy to aggregate on the bacterial surface, providing a prerequisite for killing Gram bacteria; since the bacterial cell membrane is composed of a phospholipid bilayer, the appropriate lipid-water partition coefficient and the simulated phospholipid spatial structure enable the aggregation-induced emission molecules to attach to the bacterial cell membrane; the aggregation-induced emission molecules of the present invention are easily embedded in the cell membrane of Gram bacteria when co-cultured with bacteria, so that they can effectively act on Gram bacteria. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is the hydrogen nuclear magnetic resonance spectrum of compound B in Example 1 of the present invention;

[0031] Figure 2 is the hydrogen nuclear magnetic resonance spectrum of compound C in Example 1 of the present invention;

[0032] Figure 3 is the hydrogen nuclear magnetic resonance spectrum of compound D in Example 1 of the present invention;

[0033] Figure 4 is the hydrogen nuclear magnetic resonance spectrum of compound C12 in Example 1 of the present invention;

[0034] Figure 5 is the carbon NMR spectrum of compound C12 in Example 1 of the present invention;

[0035] Figure 6 is a high-resolution mass spectrum of compound C12 in Example 1 of the present invention;

[0036] Figure 7 is the absorption spectrum of compound C12 in Example 3 of the present invention;

[0037] Figure 8 is an aggregation-induced emission (AIE) spectrum of compound C12 in Example 4 of the present invention. In the figure, the curve is 99%-0 from top to bottom, and 0, 10%, 20%, 30% ... 99% represents the volume content of toluene in the dimethyl sulfoxide / toluene mixed solution;

[0038] Fig. 9 is the AIE dot-line diagram of compound C12 in Example 4 of the present invention;

[0039] Fig.10 This is a graph showing the ROS production capacity of compound C12 under light conditions in Example 4 of the present invention;

[0040] Fig.11 is the compound C12 in Example 5 of the present invention under light conditions 1O2 production capacity diagram;

[0041] Fig.12 The colony photos of Pseudomonas syringae, Pseudomonas aeruginosa and Staphylococcus aureus on agar culture plates in the presence or absence of C12 and in darkness or white light in Example 6 of the present invention are shown;

[0042] Fig.13 The corresponding colony counts of Pseudomonas syringae, Pseudomonas aeruginosa, and Staphylococcus aureus on agar culture plates with / without C12 and in darkness / or white light in Example 6 of the present invention are statistical graphs;

[0043] Fig.14 This is a live / dead bacterial staining diagram of compound C12 in Example 7 of the present invention and Pseudomonas syringae, Pseudomonas aeruginosa, and Staphylococcus aureus after light killing. DETAILED DESCRIPTION

[0044] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] Example 1

[0046] A method for preparing an alkylpyridinium salt type aggregation-induced emission compound comprises the following steps:

[0047] (1) Synthesis of Compound B

[0048] Compound A (2.36 g, 6.16 mmol) was dissolved in chloroform (20 mL), and the mixture was cooled to 0 ° C under ice bath conditions. A solution containing dichloromethane (40 mL) and boron tribromide (24 mL, 24.64 mmol) was added dropwise to the above mixture. Then, the reaction was carried out at room temperature for 16 hours. 10 mL of methanol was added dropwise to quench the excess boron tribromide. After cooling to room temperature, the reaction mixture was extracted with ethyl acetate, the organic layer was washed with saturated sodium bicarbonate and water, dried with anhydrous Na2SO4 and concentrated. The crude product was purified by column chromatography and eluted with petroleum ether / ethyl acetate (4: 1, v: v) to obtain an off-white solid product B (1.64 g, yield: 75%).

[0049] Characterize the chemical structure of compound B, such as Figure 1 As shown, the characterization data is obtained: 1H NMR (600MHz, DMSO-d6) δ9.38 (s, 2H), 7.22 (d, J = 8.9 Hz, 2H), 6.91 (d, J = 8.7 Hz, 4H), 6.71 (d, J = 8.7 Hz, 4H), 6.55 (d, J = 8.9 Hz, 2H).

[0050] The synthetic reaction formula of compound B is as follows:

[0051]

[0052] (2) Synthesis of Compound C

[0053] Under nitrogen, compound B (1.88 g, 5.20 mmol), 4-formylphenylboronic acid (1.95 g, 13.01 mmol), Pd(dppf)Cl2 (0.38 g, 0.52 mmol) and K2CO3 (3.60 g, 26.02 mmol) were added to anhydrous toluene / methanol (1:1, v:v) solution (100 mL). The mixture was heated to 100 ° C and stirred overnight. After cooling to room temperature, water (50 mL) was added and the solution was extracted with dichloromethane. Drying with anhydrous Na2SO4 and removing the solvent under reduced pressure. Subsequently, the residue was purified by silica gel column chromatography using petroleum ether / dichloromethane (10:3, v:v) as eluent to obtain C as a brown-yellow flocculent solid (1.30 g, yield: 66%).

[0054] The chemical structure of compound C was characterized, such as Figure 2 As shown, the characterization data is obtained: 1 H NMR(600MHz,DMSO-d6)δ9.96(s,1H),9.42(s,2H),7.89(d,J=8.0Hz,2H),7.79(d,J=8.0Hz,2H ), 7.56 (d, J = 8.6Hz, 2H), 6.97 (d, J = 8.3Hz, 4H), 6.75 (d, J = 8.5Hz, 4H), 6.71 (d, J = 8.5Hz, 2H).

[0055] The synthetic reaction formula of compound C is as follows:

[0056]

[0057] (3) Synthesis of Compound D

[0058] Under N2 atmosphere, compound C (0.10 g, 0.26 mmol), 1-bromododecane (0.33 g, 1.31 mmol), KI (0.03 g, 0.18 mmol) and K2CO3 (0.18 g, 1.35 mmol) were dissolved in acetonitrile (20 mL). The reaction mixture was stirred and refluxed overnight. After cooling to room temperature, water was added and the mixture was extracted three times with dichloromethane. The extract was dried over anhydrous Na2SO4 and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography using petroleum ether / ethyl acetate (10:1, v:v) as eluent to obtain a yellow oil, namely compound D (0.11 g, yield: 60%).

[0059] The chemical structure of compound D was characterized, such as Figure 3 As shown, the characterization data is obtained: 1 H NMR (600MHz, CDCl3) δ10.00(s,1H),7.89(d,J=8.1Hz,2H),7.70(d,J=7.9Hz,2H),7.46(d,J=8.5Hz,2H),7.10(d,J=8.6Hz,4H),7.00(d,J=8.6Hz,2H ),6.86(d,J=8.8Hz,4H),3.95(t,J=6.5Hz,4H),1.80(p,J=6.8Hz,4H),1.4 7(q,J=10.7,9.1Hz,4H),1.31(d,J=10.7Hz,32H),0.91(t,J=6.9Hz,6H),.

[0060] The synthetic reaction formula of compound D is as follows:

[0061]

[0062] (4) Synthesis of Compound C12

[0063] Under N2 atmosphere, D (0.72 g, 1.00 mmol), 1,4-dimethylpyridine-1-iodide (0.23 g, 1.00 mmol) and a few drops of piperidine were added to dry ethanol (15 mL). The reaction mixture was refluxed overnight. After cooling to room temperature, the solvent was removed under reduced pressure, and the crude product was purified by a neutral alumina column using a mixture of dichloromethane / methanol (95:5, v:v) as an eluent to obtain a dark red solid C12 (0.48 g, yield: 51%), which is the alkylpyridinium salt type aggregation-induced emission compound.

[0064] The chemical structure of compound C12 was characterized, such as Figure 4-6 As shown, the characterization data is obtained: 1H NMR (600MHz, DMSO-d6) δ8.83(d,J=6.5Hz,2H),8.19(d,J=6.8Hz,2H),8.00(d,J=16.2Hz,1H ),7.76(d,J=8.5Hz,2H),7.72(d,J=8.2Hz,2H),7.58–7.55(m,2H),7.50(d,J=16.2Hz,1H), 7.02(d,J=8.9Hz,4H),6.90(d,J=9.0Hz,4H),6.80(d,J=8.7Hz,2H),4.23(s,3H),3.91(t,J =6.5Hz,4H),1.69–1.65(m,4H),1.37(d,J=7.6Hz,4H),1.22(s,32H),0.83(t,J=7.1Hz,6H). 13 C NMR (151MHz, CDCl3) δ167.74,155.76,155.54,149.00,144.82,141.71,140.16,1 32.53,132.18,130.93,130.64,129.12,128.82,127.37,126.91,126.69,126.63, 126.59,123.88,115.30,115.25,68.24,65.57,31.91,30.55,29.67,29.63,29.6 1,29.59,29.43,29.35,26.08,26.07,22.68,19.17,14.13,13.72.HRMS(ESI):m / z calcd.for C 56 H 75 N2O2[MI - ] + :807.5823, the measured molecular weight is:807.5809.

[0065] The synthetic reaction formula of compound C12 is as follows:

[0066]

[0067] Example 2

[0068] A method for preparing an alkylpyridinium salt type aggregation-induced emission compound, which differs from Example 1 only in that the amounts of compound D and 1,4-dimethylpyridine-1-iodide in step (4) are different. In this example, the molar ratio of compound D to 1,4-dimethylpyridine-1-iodide is 1:2, compound D is (0.72 g, 1.00 mmol), and 1,4-dimethylpyridine-1-iodide is (0.46 g, 2.00 mmol).

[0069] Example 3

[0070] Characterization of the photophysical properties of alkyl pyridinium salt-type aggregation-induced emission compounds:

[0071] The compound C12 prepared in Example 1 was dissolved in DMSO (dimethyl sulfoxide) solution to prepare a solution with a concentration of 10 μM for testing. Figure 7 As shown, the maximum absorption wavelength of compound C12 is around 450 nm.

[0072] Then, the target compound C12 was dissolved in a DMSO / Toluene (dimethyl sulfoxide / toluene) mixed solution with different solvent volume ratios to prepare a solution with a fixed concentration (10 μM), and its fluorescence emission spectrum was detected at an excitation wavelength of 460 nm.

[0073] like Figure 8 , 9 As shown, the fluorescence intensity of compound C12 in DMSO solution is very weak. When the volume content of toluene in the mixed solution is less than 90%, the solution has almost no fluorescence, and no aggregates are produced in this solution. When the volume content of toluene reaches 90%, compound C12 begins to aggregate and the fluorescence intensity is significantly enhanced. When the volume content of toluene is 99%, the fluorescence intensity of the solution reaches the maximum, indicating that compound C12 has typical and excellent aggregation-induced emission properties.

[0074] Figure 8 The fluorescence emission peak is located at 700nm, which belongs to the near-infrared fluorescence range. Therefore, the alkyl pyridinium salt-type aggregation-induced emission compound emits near-infrared fluorescence.

[0075] Example 4

[0076] Alkylpyridinium salt-type aggregation-induced emission compounds are used to generate reactive oxygen species:

[0077] 2,7-dichlorofluorescein diacetate (DCFH-DA) was used as a ROS indicator to measure the ROS generation of C12 under white light LED. DCFH-DA (2 mL, 5 μM) PBS solution was added to 20 μL 1 mM C12 DMSO dye solution, and the PL spectra (λ ex =485 nm). The relationship between the fluorescence intensity at 525 nm and the irradiation time was plotted to represent the generation rate of ROS.

[0078] The commercial dye Ce6 was used to replace the above C12 as a control group, and another control group without adding C12 dye was set up for adaptation.

[0079] like Fig.10 As shown, with the increase of illumination time, compared with only DCFH-DA, in the presence of C12, the fluorescence of DCFH-DA has a tendency to become stronger, indicating the generation of reactive oxygen species, which shows that C12 in Example 1 has a strong ability to generate reactive oxygen species. At the same time, it can be seen that C12 generates more reactive oxygen species than the commercial dye Ce6, and C12 can be used as a very good fluorescent probe photosensitizer for photodynamic therapy.

[0080] Example 5

[0081] Alkylpyridinium salt-type aggregation-induced emission compounds are used to generate singlet oxygen ( 1 O2):

[0082] 9,10-Anthracenediyl-bis(methylene)dicarboxylic acid (ABDA) was used as 1 O2 indicator. In the experiment, 13 μL of ABDA stock solution (7.5 mM) was added to 2 mL of C12 aqueous suspension (10 μM), and a white light LED was used as the irradiation source. The absorption of ABDA at 378 nm was recorded at different irradiation times to obtain the decay rate of the photosensitization process.

[0083] The commercial dye Ce6 was used to replace the above C12 as a control group, and another control group without adding C12 dye was set up for adaptation.

[0084] like Fig.11 As shown in the figure, with the increase of illumination time, the ultraviolet absorption of the C12 and ABDA indicator groups continued to weaken compared with the control group ABDA, indicating that more 1 O2 is produced and destroys the indicator, and it can be seen that C12 has a better ability to produce singlet oxygen than the commercial dye Ce6.

[0085] Example 6

[0086] Alkylpyridinium salt-type aggregation-induced emission compounds combined with photodynamic antibacterial activity assay: Pseudomonas syringae (P. syringae), Pseudomonas aeruginosa (P. aeruginosa) and Staphylococcus aureus (S. aureus) were used as research objects, and the photodynamic antibacterial effect of fluorescent groups with AIE effect (AIEgens) was evaluated by the plate coating method. Specifically, the following steps are included:

[0087] (1) A single colony of Pseudomonas syringae, Pseudomonas aeruginosa or Staphylococcus aureus isolated from an LB agar plate was inoculated into 5-10 mL of LB solution and cultured at 200 rpm for 10-12 h at 26° C. (Pseudomonas syringae, Pseudomonas aeruginosa) or 37° C. (Staphylococcus aureus). The solution was then centrifuged at 6500 rpm for 3 min, washed three times with 1×PBS (pH=7.4), and then serially diluted in 1×PBS to achieve the desired bacterial concentration or optical density (OD) at 600 nm, specifically OD 600 =0.3.

[0088] (2) A 40 μM 1×PBS solution of C12 prepared in Example 1 was mixed with a bacterial suspension (OD 600 =0.3) and mixed thoroughly. Each bacterial suspension treated with C12 was then divided into two groups. One group was placed in a dark environment, and the other group was placed in a 32 mW / cm 2 The treated bacterial suspension was diluted 10 3 Times, take 100 μL of each sample and evenly spread it on LB agar plate (triplicate). Incubate at 26°C (Pseudomonas syringae, Pseudomonas aeruginosa) or 37°C (Staphylococcus aureus) for 24 hours, count the bacterial colonies, and calculate the colony forming unit (CFU) survival rate. The calculation formula is as follows:

[0089]

[0090] Where A0 is the CFU count of 1x PBS, and A is the CFU count of the experimental group (C12) under dark or white light irradiation.

[0091] from Figure 12-13 It can be seen that in the group without C12 treatment, Pseudomonas syringae, Pseudomonas aeruginosa and Staphylococcus aureus grew well on the agar plate under dark and light conditions; C12 treatment alone had no obvious antibacterial effect on Pseudomonas syringae, Pseudomonas aeruginosa and Staphylococcus aureus; in the group treated with C12 and light, there was almost no visible colony growth of Pseudomonas syringae, Pseudomonas aeruginosa and Staphylococcus aureus on the agar plate, and the colony count decreased by nearly 100%, indicating that C12 can kill Gram-positive and Gram-negative bacteria through photodynamic action.

[0092] Example 7

[0093] Bacterial viability test of alkylpyridinium salt-type aggregation-induced emission compounds:

[0094] Calcein acetoxymethyl ester (Calcein-am) is a membrane permeable dye that can be used as a marker for live cells. Once inside the cell, intracellular esterases cleave the acetoxymethyl (am) group, converting it to calcein (a fluorescent dye) which is membrane impermeable. Propidium iodide (PI) is used to stain the DNA and RNA of dead bacterial cells. Bacterial viability tests using Calcein-am and PI dual staining fluorescent dyes are performed to assess membrane integrity.

[0095] Prepare bacterial suspension in 1× PBS with a bacterial concentration of 1×10 6 mL -1 . A bacterial suspension of Pseudomonas syringae, Pseudomonas aeruginosa or Staphylococcus aureus was prepared and thoroughly mixed with a 40 μM, 1×PBS solution of C12 prepared in Example 1 according to the method of Example 5. A mixture of Calcein-am (4 μM) and PI (6 μM) was added to 100 μL of the bacterial suspension mixed with C12. The solution was incubated in the dark for 15 min. After staining, the sample was washed with 1×PBS to remove excess dye. The bacteria were then imaged at 20x magnification using a Leica TCS SP8 CLSM (Leica Microsystems, Heidelberg, Germany).

[0096] like Fig.14 As shown, the confocal laser scanning microscopy (CLSM) results showed that the bacteria treated with C12 mainly emitted green fluorescence in the dark, indicating a high proportion of live bacteria. In contrast, the bacteria treated with white light and C12 mainly emitted red fluorescence, indicating that a large number of bacteria died. These observations indicate that AIEgens exhibit bactericidal activity under white light irradiation.

[0097] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the structure of the present invention or exceed the scope defined by the claims, they shall all fall within the protection scope of the present invention.

Claims

1. An alkylpyridinium salt type aggregation-induced emission compound, characterized in that: The molecular structure is as follows:

2. The alkylpyridinium salt-type aggregation-induced emission compound according to claim 1, characterized in that: The alkylpyridinium salt type aggregation-induced emission compound has near-infrared fluorescence emission.

3. A method for preparing the alkylpyridinium salt type aggregation-induced emission compound according to claim 1 or 2, characterized in that: The method comprises the following steps: stirring and refluxing the raw material D, 1,4-dimethylpyridine-1-iodide, anhydrous ethanol and piperidine overnight, cooling the reaction mixture, concentrating under reduced pressure, and eluting and purifying the crude product to obtain the alkylpyridinium salt type aggregation-induced emission compound; Wherein, the structural formula of the raw material D is as follows:

4. The method for preparing an alkylpyridinium salt type aggregation-induced emission compound according to claim 3, characterized in that: The molar ratio of the raw material D to 1,4-dimethylpyridine-1-iodide is 1:1-1:

2.

5. The method for preparing an alkylpyridinium salt type aggregation-induced emission compound according to claim 3, characterized in that: The preparation method of the raw material D comprises the following steps: mixing the raw material C, 1-bromododecane, KI and K2CO3 with acetonitrile under nitrogen, stirring and refluxing overnight, cooling to room temperature, extracting the reaction mixture with water and dichloromethane, then drying and concentrating, and purifying the crude product by silica gel elution chromatography with a mixture of petroleum ether and ethyl acetate to obtain the raw material D; Wherein, the structural formula of the raw material C is as follows:

6. The method for preparing an alkylpyridinium salt type aggregation-induced emission compound according to claim 5, characterized in that: The preparation method of the raw material C comprises the following steps: adding the raw material B, 4-formylphenylboronic acid, Pd(dppf)Cl2 and K2CO3 into an anhydrous toluene / methanol solution under nitrogen, stirring at 90-110° C. overnight, cooling to room temperature, extracting the solution with water and dichloromethane, drying and concentrating, and purifying the crude product by silica gel elution chromatography with a mixture of petroleum ether and dichloromethane to obtain the raw material C; Wherein, the structural formula of the raw material B is as follows:

7. The method for preparing an alkylpyridinium salt type aggregation-induced emission compound according to claim 6, characterized in that: The preparation method of the raw material B comprises the following steps: dissolving A in chloroform under ice bath conditions, dropping a mixed solution of dichloromethane and boron tribromide into the mixture, then reacting at room temperature for 16-18 hours, dropping methanol to quench excess boron tribromide, cooling to room temperature, extracting the reaction mixture with ethyl acetate, washing the organic layer with saturated sodium bicarbonate and water, drying and concentrating, and purifying the crude product by column chromatography with a mixed solution of petroleum ether and ethyl acetate to obtain the raw material B; Wherein, the structural formula of the raw material A is as follows:

8. Use of the alkylpyridinium salt type aggregation-induced emission compound according to claim 1, characterized in that: Under light conditions, the alkylpyridinium salt-type aggregation-induced emission compound is used to generate active oxygen and singlet oxygen.

9. The use of the alkylpyridinium salt type aggregation-induced emission compound according to claim 8, characterized in that: The alkyl pyridinium salt type aggregation-induced luminescence compound is used for preparing a fluorescent probe photosensitizer for photodynamic therapy.

10. Use of the alkylpyridinium salt type aggregation-induced emission compound according to claim 1, characterized in that: The alkylpyridinium salt type aggregation-induced luminescence compound kills Gram-positive bacteria and Gram-negative bacteria through photodynamic action.

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