Preparation Method and Application of Copper Cobalt Sulfide Nanoflowers with Chiral Optical Activity

Abstract

The present invention relates to a preparation method and application of copper cobalt sulfide nanoflowers with chiral optical activity, belonging to the technical field of material chemistry. It directly prepares copper cobalt sulfide nanoflowers by a one-step method using a copper ion solution, a cobalt ion solution, a thioacetamide solution and penicillamine. The copper cobalt sulfide nanoflowers synthesized by the present invention have mirror-symmetric chiral optical activity, and the preparation method is simple and the enantioselective catalytic performance is excellent. The prepared material has important significance for promoting the development of fields such as food industry wastewater treatment, edible mushroom production, papermaking and textile, organic synthesis, and bioenergy.

Description

Technical Field

[0001] The present invention relates to a preparation method and application of copper cobalt sulfide nanoflowers with chiral optical activity, belonging to the technical field of material chemistry. Background Art

[0002] Natural enzymes are mainly composed of proteins and have a unique chiral structure. They not only have extremely high catalytic activity but also exhibit excellent selectivity. Natural enzymes play a very important role in aspects such as substance synthesis and transformation. Although natural enzymes have high catalytic activity and excellent selectivity, the preparation and extraction processes are complex, the cost performance is low, and they are easily inactivated and difficult to store for a long time. These characteristics greatly limit the large-scale application of natural enzymes in the fields of biology, medicine, agriculture, food, etc.

[0003] In recent years, with the in-depth study of nanomaterials by people, it has been found that some nanomaterials have catalytic properties similar to natural enzymes and have the potential to replace natural enzymes. For example, metal oxides such as magnetite, carbon dots, noble metal nanoparticles such as gold / platinum nanoparticles, etc. Compared with natural nanozymes, artificially synthesized nanozymes not only have higher stability and can, to a certain extent, resist the influence of temperature, ionic strength, solvent, time, etc. on catalytic activity, but are also easier to recycle and can be recycled multiple times.

[0004] Laccase is a natural enzyme widely present in mushrooms and plants in the form of monomeric glycoproteins. It can promote the oxidation of phenolic compounds and can oxidize almost all substrates with a ρ-polyphenol similar structure, and is widely used in many fields. However, the reported research mainly focuses on the catalytic ability of nanozymes, and there are few reports on the selectivity of catalytic substrates. Chiral nanomaterials have high selectivity and stereocontrol, and can realize the selective conversion of chiral substances. Therefore, they have become the most promising alternative materials to natural enzymes. Developing and constructing nanozymes with catalytic ability similar to laccase and enantioselectivity is of great significance for promoting the development of fields such as catalytic conversion of chiral molecules, biosensing, immunoassay, cancer diagnosis, and degradation of toxic and harmful substances in the environment. Summary of the Invention

[0005] The purpose of the present invention is to overcome the above deficiencies and provide a preparation method and application of copper cobalt sulfide nanoflowers with chiral optical activity, the preparation method of which is simple and has excellent enantioselective catalytic performance.

[0006] The technical solution of the present invention is a preparation method of copper cobalt sulfide nanoflowers with chiral optical activity, which directly prepares copper cobalt sulfide nanoflowers by a one-step method using a copper ion solution, a cobalt ion solution, a thioacetamide solution, and penicillamine under alkaline conditions, and the reaction process is in an inert gas atmosphere.

[0007] Furthermore, after the reaction is carried out by the one-step method, it is necessary to continue the reaction for a period of time in an inert gas atmosphere, that is, copper cobalt sulfide nanoflowers are generated.

[0008] Furthermore, the copper cobalt sulfide nanoflowers are specifically in two chiral configurations of L- and D-.

[0009] Furthermore, the steps are as follows: prepare copper ion solution, cobalt ion solution, penicillamine solution, alkaline solution and thioacetamide solution; sequentially add the copper ion solution, cobalt ion solution and penicillamine solution into pure water, mix evenly, and then dropwise add the prepared alkaline solution and thioacetamide solution under stirring; continuously pass an inert gas into the reaction solution for high-temperature reaction; stop heating, and continue to stir the reaction under a nitrogen atmosphere at room temperature; after the reaction is completely finished, centrifuge to remove the supernatant, and resuspend the precipitate with water to obtain copper cobalt sulfide nanoflowers.

[0010] Furthermore, the copper ion solution is specifically Cu(ClO4)2 solution; the cobalt ion solution is specifically CoCl2·6H2O solution; the alkaline solution is specifically NaOH solution.

[0011] Furthermore, the concentration of the copper ion solution is 60-140 mg / mL, the concentration of the cobalt ion solution is 70-150 mg / mL, the concentration of the penicillamine solution is 90-120 mg / mL, the alkaline solution is 30-50 mg / mL NaOH solution, and the concentration of the thioacetamide solution is 80-120 mg / mL.

[0012] Furthermore, take 2-5 mL of Cu(ClO4)2 solution, 3-7 mL of CoCl2·6H2O solution and 20-40 mL of penicillamine solution and sequentially add them into 400-500 mL of pure water, and mix evenly; then dropwise add NaOH solution until the pH of the solution is 8-9, and continue to dropwise add 0.5-1.5 mL of thioacetamide solution with a concentration of 80-120 mg / mL; continuously pass an inert gas into the reaction solution to make the reaction solution react at 70-100 °C for 8-15 h; stop heating, and continue to stir the reaction under an inert gas atmosphere at room temperature for 16-36 h; after the reaction is finished, centrifuge to remove the supernatant, and resuspend the precipitate with water to obtain copper cobalt sulfide nanoflowers.

[0013] The copper cobalt sulfide nanoflowers with chiral optical activity prepared by the method.

[0014] Application of the copper cobalt sulfide nanoflowers with chiral optical activity, using them to replace laccase for catalytic oxidation reaction.

[0015] Furthermore, using them as a catalyst to catalytically oxidize L-adrenaline.

[0016] Further, 50 - 200 μL of copper cobalt sulfide nanoflowers with a concentration of 0.5 - 2 mg / mL were added to a mixed solution containing 500 - 1500 μL of PBS buffer with a pH of 6 - 8 and 60 - 180 μL of L - adrenaline with a concentration of 1 - 3 mg / mL, and the reaction was carried out for 1 - 2 h with an open mouth; the reaction solution was centrifuged at 7000 - 10000 rpm for 5 - 20 min to remove the copper cobalt sulfide nanoflowers, and adrenaline pigment was obtained.

[0017] Further, the inert gas described in the present invention is nitrogen.

[0018] The reaction mechanism of the copper cobalt sulfide nanoflowers with chiral optical activity prepared by the present invention is as Figure 12 shown. In the conventional case of the one - step preparation reaction, copper cobalt sulfide will be generated, but there will be no outer - layer flaky structure. Further anaerobic reaction after the preliminary reaction can enable a layer of nanoflower - type to grow on the outer layer of the copper cobalt sulfide core.

[0019] The present invention constructs an inorganic copper cobalt sulfide nanomaterial with chiral optical activity, which can be used as a nano - enzyme and applied to the synthesis and separation of stereoselective compounds in the pharmaceutical and industrial production fields; it can be applied to the manufacture of biosensors, and through specific signal transmission and regulation, rapid detection of biological substances can be realized, thereby improving the detection efficiency; it can be used for biological separation, thus solving the problems existing in chemical separation technology and effectively reducing pollution.

[0020] The beneficial effects of the present invention: The synthesized copper cobalt sulfide inorganic nanoparticles of the present invention have strong chiral optical activity, the preparation method is simple, they have phenol - oxidase - like activity, and the prepared nanoflower morphology increases the contact area between the nanomaterial and the catalytic substrate, thereby increasing the catalytic efficiency; the prepared materials can also be used for water treatment and soil bioremediation, and have broad application prospects in environmental catalysis and rapid detection. Description of the Drawings

[0021] Figure 1 Transmission electron microscope photograph of L - penicillamine - modified copper cobalt sulfide nanoflowers.

[0022] Figure 2 High - resolution transmission electron microscope photograph of L - penicillamine - modified copper cobalt sulfide nanoflowers.

[0023] Figure 3 EDX - Mapping diagram of L - penicillamine - modified copper cobalt sulfide nanoflowers.

[0024] Figure 4 X - ray diffraction spectrum of L - penicillamine - modified copper cobalt sulfide nanoflowers.

[0025] Figure 5X-ray electron spectroscopy of L-penicillamine modified copper cobalt sulfide nanoflowers.

[0026] Figure 6 Circular dichroism spectra of L / D-penicillamine modified copper cobalt sulfide nanoflowers.

[0027] Figure 7 Absorption spectra of L / D-penicillamine modified copper cobalt sulfide nanoflowers.

[0028] Figure 8 Fourier transform spectra of L-penicillamine modified copper cobalt sulfide nanoflowers.

[0029] Figure 9 Absorption change diagram of catalytic L-adrenaline in Application Example 2.

[0030] Figure 10 Schematic diagram of the mechanism of L / D-copper cobalt sulfide nanoflowers catalyzing L-adrenaline.

[0031] Figure 11 Kinetic comparison diagram of catalytic L-adrenaline in Application Example 2.

[0032] Figure 12 Reaction mechanism for the preparation of copper cobalt sulfide nanoflowers. Detailed implementation manners

[0033] Example 1 Synthesis of chiral copper cobalt sulfide nanoflowers

[0034] Using L-Pen and D-Pen as raw materials respectively, copper cobalt sulfide nanoflowers with different chiral configurations were synthesized.

[0035] (1) Prepare 100 mg / mL Cu(ClO4)2 solution, 100 mg / mL CoCl2·6H2O solution, 100 mg / mL penicillamine (Pen) solution, 50 mg / mL sodium hydroxide solution (NaOH), and 100 mg / mL thioacetamide solution (TAA);

[0036] (2) Add 2.38 mL of Cu(ClO4)2 solution, 3.71 mL of CoCl2·6H2O solution, and 20 mL of Pen solution into 500 mL of ultrapure water. Then, dropwise add NaOH solution to the solution under stirring until the pH value of the solution reaches 8.5, and add 0.8 mL of thioacetamide solution to it. Then, introduce nitrogen into the solution. After 30 min, heat the solution to 95 °C and react for 10 h. After the solution cools to room temperature, continue to stir the solution in a nitrogen atmosphere and react for another 24 h.

[0037] After the reaction was completed, the reaction solution was centrifuged at 10000 rpm for 15 min to remove the supernatant. Then the precipitate was redissolved in pure water and washed twice to remove the excess unreacted reactants.

[0038] Example 2 Characterization and Analysis of the Structure, Composition, and Properties of Chiral Copper Cobalt Sulfide

[0039] The physical, chemical, and optical properties of the nanoparticles prepared in Example 1 were confirmed and characterized by instruments such as a circular dichroism spectrometer, a transmission electron microscope, an X-ray electron energy spectrometer, and a Fourier transform infrared spectrometer.

[0040] The washed product solution was dropped on a copper grid. After 50 min, the solution on the copper grid was removed. After the copper grid was completely dried, its morphology was observed using a transmission electron microscope. The transmission electron microscope photos of L-Pen and the nanoflowers synthesized by L-Pen-mediated are as Figure 1 shown, and the high-resolution transmission electron microscope photos are as Figure 2 shown.

[0041] It can be seen from the electron microscope photos that monodisperse nanoflowers with a size of about 250 nm are evenly distributed in the field of view. When the magnification is increased, a region with lower contrast can be clearly observed at the edge of the nanoparticles. Through the high-resolution transmission electron microscope photo ( Figure 2 ), it can be observed that this region is an obvious flaky structure, and the overall lattice fringes are arranged in different directions.

[0042] To confirm the element distribution of the nanoflowers, EDX-Mapping was further used to characterize a single nanoflower (specifically as Figure 3 shown). It can be seen from the obtained element distribution map that the cobalt element distribution is very small in the petal parts around, but Cu and S are evenly distributed. It can be speculated that it is Cu x S. In the middle particle part with slightly higher contrast, Cu, Co, and S are evenly distributed. It can be speculated that it is Cu x Co y S.

[0043] To further confirm the speculation results, the composition of the material was confirmed using an X-ray crystal diffraction (XRD) instrument and an X-ray electron energy spectrometer (XPS). The X-ray diffraction spectrum is as Figure 4 shown, and the X-ray electron energy spectrum is as Figure 5 shown. It can be seen from the obtained XRD spectrum that the XRD of the product can respectively correspond to the standard PDF cards of #36-0380 of Cu 39 S 28 , #36-0379 of Cu9S8, and #47-1738 of Co3S4, proving that the product is composed of Cu 39 S28 , which is composed of Cu9S8 and Co3S4. Meanwhile, it can be seen from the XPS that the binding energies of copper at 932.5 and 952.5 eV correspond to the binding energies of Cu 39 S 28 and Cu9S8 respectively, while the binding energies of cobalt at 780 and 795 eV correspond to the binding energy of Co3S4. Finally, it can be determined that the synthesized nanoparticles are Cu x S-Cu x Co y S nanoflowers.

[0044] Meanwhile, the washed Cu x S-Cu x Co y S nanoflowers mediated by L-Pen and D-Pen were respectively tested with a circular dichroism spectrometer (such as Figure 6 ) and an absorption spectrometer (such as Figure 7 ). Among them, the circular dichroism spectrum is as shown in Figure 6 , and the absorption spectrum is as shown in Figure 7 . It can be observed that there is a strong mirror-symmetric chiral signal around 300 - 1000 nm, and the distribution range of the chiral signal completely corresponds to that of the absorption signal, fully demonstrating the controllable synthesis of chiral optically active D- / L-Pen-Cu x S-Cu x Co y S nanoflowers.

[0045] It can be observed from the XPS test that a certain amount of O, C, and N are contained in the product, proving that a certain amount of chiral ligand Pen is modified on the surface of the nanoparticles, and the chiral signal of the nanoparticles may be induced by these chiral ligands. To further analyze the source of the chirality of the nanoparticles, the infrared spectrum of the product was measured. According to the Fourier transform spectrum of the product (such as Figure 8 ), it can be seen that the infrared characteristic peaks such as C=O, C-H, and N-H in the nanoparticles can correspond to those of the chiral ligand. However, compared with the infrared spectrum of the chiral ligand, the peak corresponding to the mercapto group (-SH) at 2450 cm -1 in the nanoparticles does not appear, fully indicating that the surface of Cu x S-Cu x Co y S is connected to the mercapto group in the Pen molecule by covalent bonds, and the chiral ligand plays an inducing role in the generation of its chiral optical activity during the synthesis of the nanoparticles.

[0046] The above experimental results fully prove the synthesis of chiral optically active D- / L-cobalt copper sulfide nanoflowers in Example 1.

[0047] Application Example 1: Application of Chiral Copper Cobalt Sulfide Nanoflowers in Catalyzing L - Adrenaline

[0048] The catalytic reactions of L - adrenaline were carried out respectively using L - type copper cobalt sulfide nanoflowers (L - Pen - NF), laccase and the catalyst - free group, and the reaction results were compared.

[0049] The first group: 100 μL of L - type copper cobalt sulfide nanoflowers (L - Pen - NF) (1 mg / mL) synthesized by the hydrothermal method in Example 1 was added to a mixed solution containing 800 μL of PBS buffer (pH 7.0) and 100 μL of L - adrenaline (1 mg / mL);

[0050] The second group: 100 μL of laccase (1 mg / mL) was added to a mixed solution containing 800 μL of PBS buffer (pH 7.0) and 100 μL of L - adrenaline (1 mg / mL);

[0051] The third group: No catalyst was added as a blank control (Blank).

[0052] After the three groups of reaction solutions were reacted open - mouthed for a period of time, they were centrifuged at 10000 rpm for 5 min to remove the copper cobalt sulfide nanoflowers in the first group.

[0053] The ultraviolet absorption spectra of the three groups of reactants were measured respectively with a UV - visible spectrophotometer, and the specific results are as Figure 9 shown. The solution turning orange - red and the characteristic peak at 485 nm (ox - DQ) increasing can indicate that the copper cobalt sulfide nanoflowers have good phenol - oxidase - like activity. L - adrenaline is oxidized to adrenochrome (as Figure 10 ).

[0054] Application Example 2: Effect of Chiral Copper Cobalt Sulfide Nanoflowers in Catalyzing L - Adrenaline

[0055] 20 μL of laccase (1 mg / mL) and 20 μL of L - type or D - type copper cobalt sulfide nanoflowers (D - Pen - NF) (1 mg / mL) synthesized by the hydrothermal method in Example 1 were respectively taken and added to 180 μL of PBS solution containing 0.1 mM, 0.2 mM, 0.4 mM, 0.8 mM, 1.6 mM L - adrenaline. The change of the ultraviolet absorption spectrum at 485 nm with time was measured with an enzyme - label instrument; Using the Michaelis - Menten equation (where the K m value is called the Michaelis constant, V max is the reaction rate when the enzyme is saturated with the substrate, and [S] is the substrate concentration) to calculate the change curve of the reaction rate of the catalyst with the concentration of L - adrenaline.

[0056] The kinetic comparison diagram of L / D-cobalt copper sulfide nanoflowers catalyzing L-adrenaline is as Figure 11 shown. The statistical table of kinetic parameters of L / D-cobalt copper sulfide nanoflowers catalyzing L-adrenaline is shown in Table 1, where K cat is the catalytic constant.

[0057] Table 1

[0058]

[0059] As Figure 11 can be seen from the data recorded in and Table 1, with the increase of the concentration of L-adrenaline, the catalytic rate of cobalt copper sulfide nanoflowers gradually increases, and the catalytic rate of the L-type material is faster than that of the D-type material.

Claims

1. Preparation method of copper cobalt sulfide nanoflowers with chiral optical activity, characterized in that The steps are as follows: prepare copper ion solution, cobalt ion solution, penicillamine solution, alkaline solution and thioacetamide solution; Add the copper ion solution, cobalt ion solution and penicillamine solution into pure water in sequence. After mixing evenly, dropwise add the prepared alkaline solution and thioacetamide solution under stirring; continuously pass inert gas into the reaction solution to make the reaction solution react at a high temperature of 70 - 100 °C; stop heating and continue stirring the reaction under a nitrogen atmosphere at room temperature; after the reaction is completely finished, centrifuge to remove the supernatant, and resuspend the precipitate with water to obtain copper cobalt sulfide nanoflowers; finally, after confirmation and characterization, it is proved that copper cobalt sulfide nanoflowers with chiral optical activity are synthesized.

2. The preparation method of the copper cobalt sulfide nanoflowers with chiral optical activity as described in claim 1, characterized in that: The copper cobalt sulfide nanoflowers are specifically in two chiral configurations of L- and D-.

3. The preparation method of the copper cobalt sulfide nanoflowers with chiral optical activity as described in claim 1, characterized in that: The copper ion solution is specifically Cu(ClO4)2 solution; the cobalt ion solution is specifically CoCl2·6H2O solution; the alkaline solution is specifically NaOH solution.

4. The preparation method of the copper cobalt sulfide nanoflowers with chiral optical activity according to claim 3, characterized in that: The concentration of the copper ion solution is 60 - 140 mg / mL, the concentration of the cobalt ion solution is 70 - 150 mg / mL, the concentration of the penicillamine solution is 90 - 120 mg / mL, the alkaline solution is 30 - 50 mg / mL NaOH solution, and the concentration of the thioacetamide solution is 80 - 120 mg / mL.

5. The preparation method of the copper cobalt sulfide nanoflowers with chiral optical activity as described in claim 4, characterized in that: Take 2 - 5 mL of Cu(ClO4)2 solution, 3 - 7 mL of CoCl2·6H2O solution and 20 - 40 mL of penicillamine solution and add them into 400 - 500 mL of pure water in sequence, and mix evenly; then dropwise add NaOH solution until the pH of the solution is 8 - 9, and continue to dropwise add 0.5 - 1.5 mL of thioacetamide solution with a concentration of 80 - 120 mg / mL; continuously pass inert gas into the reaction solution to make the reaction solution react at 70 - 100 °C for 8 - 15 h; stop heating and continue stirring the reaction for 16 - 36 h under an inert gas atmosphere at room temperature; after the reaction is finished, centrifuge to remove the supernatant, and resuspend the precipitate with water to obtain copper cobalt sulfide nanoflowers.

6. Copper cobalt sulfide nanoflowers with chiral optical activity prepared by the method according to any one of claims 1 - 5.

7. The application of the copper cobalt sulfide nanoflowers with chiral optical activity as claimed in claim 6, characterized in that: Replace laccase with it for catalytic oxidation reaction.

8. Use of the copper cobalt sulfide nanoflowers with chiral optical activity according to claim 7, characterized in that: Use it as a catalyst to catalytically oxidize L - adrenaline.

9. Application of the copper cobalt sulfide nanoflowers with chiral optical activity as described in claim 8, characterized in that: Take 50 - 200 μL of copper cobalt sulfide nanoflowers with a concentration of 0.5 - 2 mg / mL and add them to a mixed solution containing 500 - 1500 μL of PBS buffer with a pH of 6 - 8 and 60 - 180 μL of L - adrenaline with a concentration of 1 - 3 mg / mL, and react with an open mouth for 1 - 2 h; centrifuge the reaction solution at 7000 - 10000 rpm for 5 - 20 min to remove the copper cobalt sulfide nanoflowers to obtain adrenochrome.

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