Preparation method of cobalt-based chiral enantiomer superparticle and cobalt-based chiral enantiomer superparticle

Abstract

The invention discloses a preparation method of a cobalt-based chiral enantiomer superparticle and the cobalt-based chiral enantiomer superparticle, and the preparation method comprises the following steps: stirring a mixture containing a cobalt source solution and an amino acid solution for reaction under an alkaline condition to obtain the cobalt-based chiral enantiomer superparticle, amino acid in the amino acid solution is L-cystine and / or D-cystine. The cobalt-based superstructure particles synthesized by the method have good chiral optical activity in a visible light region and a near-infrared light region, and have important guiding significance for preparing chiral enantiomer structure materials and exploring an assembly mechanism generated by a chiral ligand-induced chiral structure.

Description

Technical Field

[0001] The present application relates to a preparation method of cobalt-based chiral enantiomeric superparticles and cobalt-based chiral enantiomeric superparticles, belonging to the technical field of nanomaterial synthesis. Background Art

[0002] Chirality is a basic property of nature. The life system itself is a typical chiral structure, for example, the left hand and the right hand are mirror-symmetric structures. As the origin of life, amino acid molecules are all left-handed and sugar molecules are all right-handed. Although the two compounds that are enantiomers have exactly the same chemical composition, they often exhibit completely different functional properties. For example, in the "Thalidomide" incident, the chiral drug thalidomide R enantiomer had a sedative effect on pregnant women, while the S enantiomer caused fetal malformations. The results showed that in addition to the elemental composition, the three-dimensional spatial conformation is crucial to the chemical properties of the substance. But so far, people still don't know how chiral molecules are expressed at various scales and how chirality affects the morphology, structure and function of the final assembly.

[0003] Chiral inorganic nanomaterials, as a bio-friendly functional material, not only have the electrical, optical, and magnetic properties of nanomaterials, but also rely on the stereoselectivity of chirality to re-endow chiral nanomaterials with unique functional properties. Chiral multi-level nanoassembly materials constructed with chiral biomolecules and inorganic nano-elements provide multi-scale and multi-dimensional possibilities for their interaction with various biological systems due to their highly sensitive optical response and rich and adjustable morphology and spatial topological structure. In recent years, they have great application potential in the fields of biosensing, chiral catalysis, disease analysis, and medical imaging.

[0004] With the rapid development of nanotechnology in today's era, the rational design and precise construction of nano-assemblies with specific structures and functions have gradually become a hot topic of common concern among scientists around the world. Assemblies constructed in different ways have huge differences in structure, which leads to great differences in their functions. Furthermore, fully mastering the non-covalent interactions between different assembly units to achieve precise construction of nanostructures will help to better understand the assembly process in natural systems, and also provide a strong basis for artificial simulation of natural systems, thereby creating more practical value for mankind.

[0005] Cobalt is a common transition metal element with a silvery white color and a slight pink tint, and its common valence is +2 or +3. In addition, cobalt is also an important component of vitamin B12. The preparation of cobalt-based enantiomeric materials induced by chiral amino acids not only provides a simple method for the synthesis of chiral materials, but also provides a basis for the application of functional materials in the field of biosensors. Summary of the invention

[0006] In view of the shortcomings of the prior art, a method for preparing a class of chiral enantiomeric materials using amino acids is provided. The chiral cobalt-based materials prepared by the present invention have enantiomeric chiral structures, and chiral ligands induce chiral optical responses in both the visible light region and the near-infrared light region. The materials synthesized by the present invention are all synthesized at room temperature, and the synthesis method is simple and easy to prepare on a large scale.

[0007] According to one aspect of the present application, a method for preparing cobalt-based chiral enantiomeric superparticles is provided, the preparation method comprising:

[0008] Under alkaline conditions, a mixture containing a cobalt source solution and an amino acid solution is stirred for reaction to obtain the cobalt-based chiral enantiomeric superparticles;

[0009] The amino acid in the amino acid solution is L-cystine and / or D-cystine.

[0010] Optionally, the cobalt source in the cobalt source solution is selected from at least one of cobalt acetate, cobalt chloride, cobalt sulfate and cobalt nitrate.

[0011] Optionally, the volume ratio of the cobalt source solution to the amino acid solution is 1:0.5-4.

[0012] Optionally, the volume ratio of the cobalt source solution to the amino acid solution is selected from any value of 1:0.5, 1:1, 1:2, 1:3, 1:4 or a range between any two of the above.

[0013] Optionally, the concentration of the cobalt source solution is 25-30 mg / mL.

[0014] Optionally, the concentration of the cobalt source solution is selected from any value of 25 mg / mL, 26 mg / mL, 27 mg / mL, 28 mg / mL, 29 mg / mL, 30 mg / mL or a range between any two of the above values.

[0015] Optionally, the concentration of the amino acid solution is 25-50 mg / mL.

[0016] Optionally, the concentration of the amino acid solution is selected from any value of 25 mg / mL, 30 mg / mL, 35 mg / mL, 40 mg / mL, 45 mg / mL, 50 mg / mL or a range between any two of the above.

[0017] Optionally, the pH value of the mixture is 8-10.

[0018] Optionally, the alkaline solution in the alkaline condition is selected from at least one of a sodium hydroxide solution, a potassium hydroxide solution, and a sodium carbonate solution.

[0019] Optionally, the rotation speed of the stirring reaction is 400 to 800 rpm / min.

[0020] Optionally, the stirring reaction time is 4 to 8 hours.

[0021] Optionally, the stirring reaction time is selected from any value of 4h, 5h, 6h, 7h, 8h or a range between any two of the above.

[0022] According to another aspect of the present application, there is provided a cobalt-based chiral enantiomeric superparticle prepared by the above-mentioned preparation method, wherein the particle size of the cobalt-based chiral enantiomeric superparticle is 0.5-2 um.

[0023] Optionally, the characteristic peak of the circular dichroism spectrum signal of the cobalt-based chiral enantiomeric superparticles is 400-600nm or 900-1000nm.

[0024] Optionally, the chiral cobalt-based superparticles with L-cystine or D-cystine as ligands have a particle size of about 1 μm and characteristic peaks at 400 nm and 900 nm.

[0025] As a specific implementation, the present application is implemented through the following technical solutions:

[0026] A method for synthesizing a chiral amino acid-induced chiral cobalt-based superstructure material comprises the following steps: using L-cystine and D-cystine as chiral ligands, using cobalt acetate tetrahydrate as a cobalt source, and inducing the generation of a cobalt-based enantiomeric superstructure by stirring the reaction under alkaline reaction conditions.

[0027] Furthermore, the synthesis method specifically comprises the following steps:

[0028] S1. Adjust the alkalinity of the L-cystine and D-cystine chiral ligand solutions to fully dissolve them, then add the tetrahydrate cobalt acetate solution and the L-cystine and D-cystine chiral ligands to water in sequence, and rapidly stir and react for 4-8 hours to obtain a reaction solution of a cobalt-based chiral enantiomeric superstructure;

[0029] S2. The final product is purified by centrifugation to obtain the cobalt-based chiral enantiomeric superstructure material.

[0030] Furthermore, in step S1, when the cobalt acetate tetrahydrate solution reacts with the L-cystine and D-cystine solutions respectively, an alkaline solution is added to the L-cystine and D-cystine to adjust the pH to 8-10, and the alkaline solution is a sodium hydroxide solution, a potassium hydroxide solution or a sodium carbonate solution.

[0031] In the present invention, during the specific operation, a tetrahydrated cobalt acetate aqueous solution can be prepared at room temperature, and then L-cystine and D-cystine aqueous solutions are respectively prepared, and the pH value of the L-cystine or D-cystine solution is adjusted to 8-10 with a sodium hydroxide solution to fully dissolve the L-cystine or D-cystine solution. The prepared tetrahydrated cobalt acetate solution and L-cystine or D-cystine solution are sequentially added into a conical flask containing ultrapure water, and reacted by magnetic stirring at room temperature, and it can be observed that the color of the solution is milky white and gradually deepens.

[0032] The beneficial effects of this application include:

[0033] The present application provides a method for preparing a class of amino acid-induced chiral cobalt-based superparticles. The synthesized L and D-configured cobalt-based superparticles both have good chiral optical activity in the visible light region and near-infrared light region, and the circular dichroism spectrum shows very good symmetry, which is of great significance for preparing materials with enantiomeric chiral structures and studying the mechanism of chiral ligand-induced chiral structure formation. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a scanning electron microscope (SEM) image of the cobalt-based superparticles synthesized by L-cystine induction prepared in Example 1 of the present application, with a scale of 1.00 μm.

[0035] Figure 2 This is a scanning electron microscope (SEM) image of the cobalt-based superparticles synthesized by D-cystine induction prepared in Example 1 of the present application, with a scale of 1.00 μm.

[0036] Figure 3 Circular dichroism spectra of the cobalt-based superparticles synthesized by L-cystine and the cobalt-based superparticles synthesized by D-cystine in Example 2 of the present application.

[0037] Figure 4 This is an absorption spectrum diagram of the cobalt-based superparticles synthesized by L-cystine and the cobalt-based superparticles synthesized by D-cystine in Example 2 of the present application. DETAILED DESCRIPTION

[0038] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

[0039] Unless otherwise specified, the raw materials in the examples of this application were purchased through commercial channels.

[0040] The experimental methods in the following examples without specifying specific conditions are usually carried out under conventional conditions or under conditions recommended by the manufacturers.

[0041] Circular dichroism spectroscopy characterization:

[0042] The circular dichroism spectrum was tested using a Chirascan V100 circular dichroism spectrometer from Applied Photophysics, UK, with a detection wavelength range of 300-1000 nm.

[0043] Scanning electron microscopy characterization:

[0044] Scanning electron microscope (SEM) images were taken using Hitachi SU8100, Japan, with an accelerating voltage of 15 KV. UV-visible light absorption was tested using the Thermo Fisher BioMate 3S UV-visible absorption spectrometer.

[0045] Example 1: Preparation of Chiral Amino Acid-Induced Cobalt-Based Chiral Enantiomeric Superparticles

[0046] (1) First, weigh 250 mg of cobalt acetate tetrahydrate solid powder and add it to 10 mL of ultrapure water to dissolve it. Then, prepare 100 mM L-cystine and D-cystine aqueous solutions respectively. Weigh 240 mg of two chiral ligands and dissolve them in 8 mL of water. Use 2 mL of 1 M sodium hydroxide solution to adjust the pH value of the chiral ligand solution to about 8-10. Then, add 1 mL of the prepared cobalt acetate tetrahydrate solution and 2 mL of L-cystine or D-cystine solution to a glass bottle containing 18 mL of ultrapure water. React for 8 h under magnetic stirring. It can be observed that the color of the solution turns milky white.

[0047] (2) The obtained L-type and D-type chiral cobalt-based superparticles were separated by centrifugation to obtain products, and the centrifugal speed was 5000 rpm for 10 minutes. The supernatant was removed and the precipitate was resuspended in ultrapure water; the purified material was used for circular dichroism spectroscopy testing and scanning electron microscopy morphology characterization.

[0048] (3) Preparation of chiral cobalt-based superparticles: The chiral optical signals generated by the nanoparticles synthesized with L-cystine and D-cystine are symmetrical, and the positions of the characteristic peaks are the same, both at 400nm and 900nm, and the particle size is about 1μm.

[0049] Example 2: Characterization method of chiral cobalt-based ultra-small nanoparticles induced by chiral amino acid-based ligand analogs

[0050] (1) Circular dichroism spectroscopy characterization: The chiral cobalt-based nanomaterials obtained by centrifugation purification were resuspended in ultrapure water and diluted to 2 mg / mL. Ultrapure water was used as the baseline background. The scanning wavelength range was 300 to 1000 nm and the scanning speed was 1 s / nm. The circular dichroism spectra and UV-visible absorption spectra of the materials synthesized with L-cystine and D-cystine were obtained. Figure 3 and Figure 4 ),from Figure 3It can be seen that the material has obvious circular dichroism characteristic peaks at 400nm and 900nm wavelengths, and the circular dichroism spectra of the synthetic materials with L-cystine and D-cystine are symmetrically distributed; Figure 4 It can be seen that the material has obvious absorption in the range of 300-1000nm, without obvious characteristic peaks.

[0051] (2) Scanning electron microscopy characterization: The chiral cobalt-based ultra-small nanoparticles obtained by centrifugation purification were resuspended in ultrapure water and diluted to a concentration of 1 mg / mL. 5 μL was dropped on the surface of a silicon wafer and allowed to stand until the water was completely evaporated. The particles were then placed under an infrared lamp for heating and drying for 10 minutes. The morphology was observed under a cold field scanning electron microscope at a voltage of 3-5 kV. The electron micrograph of the material synthesized with L-cystine ( Figure 1 ), electron micrograph of the material synthesized with the participation of D-cystine ( Figure 2 ),from Figure 1 and Figure 2 It can be seen that the particle size of L-cystine and D-cystine involved in the synthesis of materials is the same, showing a multi-level helical conformation, and the scanning electron microscopy results of L-type materials and D-type materials show an obvious mirror-symmetrical structural distribution.

[0052] The above are only a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method for preparing cobalt-based chiral enantiomeric superparticles, characterized in that: The preparation method comprises: Under alkaline conditions, a mixture containing a cobalt source solution and an amino acid solution is stirred for reaction to obtain the cobalt-based chiral enantiomeric superparticles; The amino acid in the amino acid solution is L-cystine and / or D-cystine.

2. The preparation method according to claim 1, characterized in that: The cobalt source in the cobalt source solution is selected from at least one of cobalt acetate, cobalt chloride, cobalt sulfate and cobalt nitrate.

3. The preparation method according to claim 1, characterized in that: The volume ratio of the cobalt source solution to the amino acid solution is 1:0.5-4.

4. The preparation method according to claim 1, characterized in that: The concentration of the cobalt source solution is 25-30 mg / mL; Preferably, the concentration of the amino acid solution is 25-50 mg / mL.

5. The preparation method according to claim 1, characterized in that: The pH value of the mixture is 8-10.

6. The preparation method according to claim 1, characterized in that: The alkaline solution in the alkaline condition is selected from at least one of a sodium hydroxide solution, a potassium hydroxide solution, and a sodium carbonate solution.

7. The preparation method according to claim 1, characterized in that: The rotation speed of the stirring reaction is 400-800 rpm / min.

8. The preparation method according to claim 1, characterized in that: The stirring reaction time is 4 to 8 hours.

9. The cobalt-based chiral enantiomeric superparticles prepared by the preparation method according to any one of claims 1 to 8, characterized in that: The particle size of the cobalt-based chiral enantiomer superparticles is 0.5-2 μm.

10. The cobalt-based chiral enantiomeric superparticle according to claim 9, characterized in that: The characteristic peak of the circular dichroism spectrum signal of the cobalt-based chiral enantiomeric superparticle is 400-600nm or 900-1000nm.

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