Helical polymers with near-infrared I absorption, their preparation methods and uses

Abstract

The present invention discloses a helical polymer with absorption in the first near-infrared region, its preparation method and uses, which relates to the technical field of helical polymers. The present invention synthesizes a helical polymer with a novel structure. The synthesis method adopted is not only green and environmentally friendly, but also can reduce costs. Moreover, this helical polymer has the characteristic of absorption in the first near-infrared region and can be used for cell and tissue imaging to track the activities and reactions of biofunctional molecules in vivo.

Description

Technical Field:

[0001] The present invention relates to the technical field of helical polymers, and particularly relates to a helical polymer with absorption in the first near-infrared region, and a preparation method and use thereof. Background Art:

[0002] Helical polymers, also known as helical molecules, are a class of macromolecules widely existing in nature. For example, biological macromolecules such as DNA and proteins have helical conformations. Due to their precise and ordered chemical structures, they exhibit excellent properties and potential application values, thus attracting the close attention of scientists. So far, the development of helical polymers has been rapid, involving various fields such as molecular recognition, chiral recognition, chiral catalysis, and biological imaging.

[0003] Usually, the synthesis of helical polymers requires initiators or solvents for polymerization, and the solvents used in the polymerization process are toxic, with complex post-treatment and certain pollution to the environment. The present invention self-polymerizes into helical polymers without solvents, which is an environmentally friendly, green, and simple polymerization method. At the same time, it also reduces costs and avoids waste of natural resources. The self-polymerized helical polymers have a wide absorption range, reaching the first near-infrared region, and can be used for biological imaging to realize the tracking of single biological functional molecules in vivo and reveal their biological functions. Summary of the Invention:

[0004] The technical problem to be solved by the present invention is to provide a helical polymer and a preparation method thereof. The helical polymer has the characteristic of absorption in the first near-infrared region and can be applied to fields such as biological imaging.

[0005] One object of the present invention is to provide a helical polymer, and the structural formula is as follows:

[0006]

[0007] Wherein, R = C8H 17 , C2H5; n = 2 - 100.

[0008] Another object of the present invention is to provide a preparation method of the helical polymer. Intermediate 1 is obtained by reacting carbon disulfide with zinc chloride and tetrabutylammonium bromide. Intermediate 2 is obtained by reacting Intermediate 1 with RBr. The monomer is obtained by reacting Intermediate 2 with Br-Ar-CHO. The monomer undergoes a self-polymerization reaction under solvent-free conditions to generate the helical polymer.

[0009] The synthesis route is as follows:

[0010]

[0011] Wherein, R = C8H 17 , C2H5; n = 2 to 100.

[0012] A third object of the present invention is to provide the use of the helical polymer in the fields of biological imaging and the like.

[0013] The beneficial effects of the present invention are as follows: A novel-structured helical polymer is synthesized in the present invention. The synthesis method adopted is not only green and environmentally friendly, but also can reduce costs. Moreover, the helical polymer has the characteristic of absorption in the first near-infrared region and can be used for cell and tissue imaging to track the activities and reactions of biofunctional molecules in vivo. Description of the Drawings:

[0014] Figure 1 1H NMR spectra of Intermediate 2, monomer-triethyl phosphite complex and helical polymer of the present invention;

[0015] Figure 2 MALDI-TOF (Matrix-Assisted Laser Desorption / Ionization Time-of-Flight Mass Spectrometry) spectrum of the helical polymer of the present invention;

[0016] Figure 3 GPC (Gel Permeation Chromatography) spectrum of the helical polymer of the present invention;

[0017] Figure 4 SEM (Scanning Electron Microscope) image of the helical polymer of the present invention;

[0018] Figure 5 UV-Vis (Ultraviolet-Visible Absorption Spectrum) spectra of the helical polymer of the present invention in solvents and thin films. Detailed Embodiments:

[0019] In order to make the technical means, creative features, achieved purposes and effects of the present invention easy to understand, the present invention will be further described below in conjunction with specific embodiments and illustrations.

[0020] The present invention provides a helical polymer, the structural formula of which is shown as follows:

[0021]

[0022] wherein, R = C8H 17 , C2H5; n = 2 to 100.

[0023] The present invention also provides a preparation method of the helical polymer. Intermediate 1 is obtained by reacting carbon disulfide with zinc chloride and tetrabutylammonium bromide. Intermediate 2 is obtained by reacting Intermediate 1 with RBr. The monomer is obtained by reacting Intermediate 2 with Br-Ar-CHO. The monomer undergoes a self-polymerization reaction under solvent-free conditions to generate the helical polymer.

[0024] The synthesis route is shown as follows:

[0025]

[0026] Among them, R = C8H 17 , C2H5; n = 2 to 100.

[0027] The molar ratio of carbon disulfide, zinc chloride, and tetrabutylammonium bromide is 12:1.1:1 to 15:1.5:1.

[0028] The molar ratio of intermediate 1 to 1-bromooctane is 1:4 to 1:5.

[0029] The molar ratio of intermediate 2 to 5-bromothiophene-2-carbaldehyde is 1:1 to 1:1.2.

[0030] The monomer undergoes self-polymerization under the initiation of light or heat.

[0031] Monomers usually undergo polymerization reactions in initiators or solvents, but the monomers described in the present invention can undergo self-polymerization under solvent-free conditions, forming polymers with high molecular weights and a helical geometric structure, breaking the traditional polymerization mode.

[0032] The present invention also provides the use of the helical polymer in the fields of bioimaging and the like.

[0033] The present invention will be described in detail below through examples.

[0034] Example 1

[0035]

[0036] Synthesis of intermediate 1: Cut sodium (11.5 g, 0.5 mol) into small pieces and put it into a flask. Wash the flask with n-hexane and evaporate it under vacuum. Add carbon disulfide (90 mL), and dropwise add DMF (100 mL) under an ice bath. Stir overnight at room temperature; dropwise add methanol (25 mL) to quench sodium under an ice bath, then dropwise add an aqueous solution of ZnCl2 (20.4 g, 0.15 mol) in ammonia water (250 mL), and add water (200 mL) and methanol (200 mL). Then dropwise add an aqueous solution of (n-Bu)4NBr (38.6 g, 0.12 mol) in water (125 mL), stir overnight at room temperature, filter, wash, and dry under vacuum to obtain intermediate 1.

[0037] Example 2

[0038]

[0039] Synthesis of intermediate 2: Weigh intermediate 1 (2.2 g, 2.5 mmol) and dissolve it in acetonitrile (80 mL), add C8H17 Br (2.0 g, 10.4 mmol) was heated to 80 °C and refluxed for 3 h. After the reaction was completed, it was cooled to room temperature. The solvent was removed under vacuum. The reaction solution was extracted with a mixed solution of dichloromethane and water. The organic phase was dried and purified by column chromatography (petroleum ether) to obtain Intermediate 2. 1 1H-NMR (CDCl3, 400 MHz) δ 2.89 - 2.87 (t, J = 4.00 Hz, 4H), 1.7 - 1.65 (m, 4H), 1.45 - 1.38 (m, 4H), 1.34 - 1.26 (m, 16H), 0.90 - 0.86 (t, J = 8.00 Hz, 6H).

[0040] Example 3

[0041]

[0042] Synthesis of monomer-triethyl phosphite complex: Intermediate 2 (0.82 g, 1.95 mmol) and 5-bromothiophene-2-carbaldehyde (0.37 g, 1.95 mmol) were dissolved in toluene (20 mL). The mixture was heated to 120 °C, and then triethyl phosphite (10 mL) was slowly added. The mixture was refluxed for 4 h. After the reaction was completed, it was cooled to room temperature. The solvent was removed under vacuum. The reaction solution was extracted with a mixed solution of dichloromethane and water. The organic phase was dried and purified by column chromatography (petroleum ether / dichloromethane = 5 / 1, v / v). The solvent was evaporated to dryness to obtain the monomer-triethyl phosphite complex (the monomer self-polymerized after removing triethyl phosphite). 1 1H-NMR (CDCl3, 400 MHz) δ 6.95 - 6.94 (d, J = 4.00 Hz, 1H), 6.64 - 6.63 (d, J = 4.00 Hz, 1H), 6.58 (s, 1H), 2.85 - 2.76 (m, 4H), 1.68 - 1.62 (m, 4H), 1.42 - 1.25 (m, 22H), 0.88 - 0.86 (m, 7H).

[0043] Example 4

[0044]

[0045] Synthesis of helical polymer: The monomer-triethyl phosphite complex was dried under vacuum to remove triethyl phosphite. The resulting monomer was rapidly self-polymerized under the initiation of heat or light (room temperature and indoor light) to obtain the helical polymer. 1 1H-NMR (CDCl3, 400 MHz) δ 7.14 - 6.30 (m, 2H), 3.10 - 2.62 (m, 4H), 1.82 - 1.5 (m, 4H), 1.5 - 1.2 (m, 21H), 0.9 - 0.8 (m, 6H).

[0046] The structural characterization and performance testing of the helical polymer synthesized in this invention are as follows. The results are shown in Figures 1-5 .

[0047] From Figure 1 it can be seen that the helical polymer with the said structure is successfully synthesized in this invention.

[0048] From Figure 2 it can be seen that for the spectrogram of the helical polymer with a molecular weight of around 2000, the difference between adjacent main peaks is 316.6 g / mol, and the molecular weight of the monomer unit is 316, corresponding to the molecular weight of one structural unit, which proves that the structural unit of the polymer is exactly the structure of the monomer unit. The differences between the main peak and the adjacent secondary peaks on both sides are 78.3 g / mol and 79.4 g / mol, corresponding to the molecular weight of bromine at the end of the polymer, indicating that the H on the other side of the end is likely to drop off, resulting in bromination capping.

[0049] From Figure 3 it can be seen that the number-average molecular weight Mn of the polymer in this invention is 11464, the degree of polymerization n is 36, and the polydispersity index Mw / Mn is 1.55; the number-average molecular weight Mn of the polymer is 2378, the degree of polymerization n is 7, and the polydispersity index Mw / Mn is 1.22. The molecular weight of the polymer is relatively large, and the polydispersity index is close to 1, indicating that its molecular weight distribution is relatively narrow and the molecular weight is relatively uniform.

[0050] From Figure 4 it can be seen that the long-chain structure of the polymer in this invention is helical.

[0051] From Figure 5 it can be seen that the maximum absorption wavelength of the polymer in this invention in dichloromethane is 419 nm, and the maximum absorption wavelength of the polymer film is 849 nm, reaching the absorption range of the first near-infrared region. The absorption wavelength range of the polymer film is 350 - 860 nm, indicating that the polymer film has a wide absorption range and can capture more photons. Utilizing this property, this polymer can be applied to fields such as bioimaging.

[0052] The above shows and describes the basic principles, main features, and advantages of this invention. Those skilled in the art should understand that this invention is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principles of this invention. Without departing from the spirit and scope of this invention, this invention will have various changes and improvements, and these changes and improvements all fall within the scope of this invention claimed. The scope of protection claimed for this invention is defined by the appended claims and their equivalents.

Claims

1. A helical polymer, characterized in that, The structural formula is as follows: wherein, R = C8H 17 , C2H5; n = 2 to 100.

2. The method for preparing the helical polymer according to claim 1, wherein: Intermediate 1 is obtained by reacting carbon disulfide with zinc chloride and tetrabutylammonium bromide. Intermediate 1 reacts with RBr to obtain Intermediate 2. Intermediate 2 reacts with Br-Ar-CHO to obtain a monomer, and the monomer undergoes a self-polymerization reaction under solvent-free conditions to form a helical polymer; The synthetic route is as follows: Among them, R = C8H 17 , C2H5; n = 2 to 100.

3. The preparation method according to claim 2, wherein: The molar ratio of the carbon disulfide to the zinc chloride and the tetrabutylammonium bromide is 12:1.1:1 to 15:1.5:

1.

4. The preparation method according to claim 2, characterized in that: The molar ratio of the Intermediate 1 to 1-bromooctane is 1:4 to 1:

5.

5. The preparation method according to claim 2, wherein: The molar ratio of the Intermediate 2 to 5-bromothiophene-2-carbaldehyde is 1:1 to 1:1.

2.

6. The preparation method according to claim 2, characterized in that: The monomer undergoes a self-polymerization reaction under the initiation of light or heat.

7. Use of the helical polymer according to claim 1 or the helical polymer obtained by the preparation method according to any one of claims 2-6 in bioimaging.

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