Rare-earth-based magnet material, preparation method and application

Abstract

The invention belongs to the technical field of magnetic functional materials. The invention discloses a rare-earth-based magnet material, a preparation method and application. The chemical formula of the rare earth based magnet material disclosed by the invention is [Gd5 (L) 12 (mu3-OH) 2 (H2O) 2] Cl. 5EtOH. 5CH3CN. 11H2O, and L is 2-hydroxy-1-naphthaldehyde. The rare earth-based magnet material disclosed by the invention can be used as a magnetic refrigeration material and a magnetic resonance imaging contrast agent, a better imaging effect can be realized at a lower dosage by utilizing the advantage of high nuclear number, the image contrast and definition are improved, an imaging window is prolonged, and further comprehensive diagnosis and reduction of potential toxicity are facilitated.

Description

Technical Field

[0001] The present application belongs to the technical field of magnetic functional materials, and in particular relates to a rare earth-based magnetic material, a preparation method and an application thereof. Background Art

[0002] Gd-based rare earth complexes are a type of nanomaterials whose magnetism originates from the molecular level. They have the characteristics of magnetic isotropy and size uniformity. Due to their unique magnetic and quantum properties, they have shown excellent application potential in many cutting-edge fields such as magnetic resonance imaging, quantum computing and magnetic cooling materials. However, existing contrast agents have defects such as poor imaging effect and unclear contrast. Summary of the invention

[0003] Purpose of the invention: This application provides a rare earth-based magnetic material, preparation method and application. The rare earth-based magnetic material of this application can be used in the preparation of magnetic resonance contrast agents, solving the defects of poor imaging effect and unclear contrast of contrast agents in the prior art.

[0004] Technical solution: The embodiment of the present application provides a rare earth-based magnet material, the chemical formula of the rare earth-based magnet material is: [Gd5(L) 12 ( m 3-OH)2(H2O)2]Cl·5EtOH·5CH3CN·11H2O, wherein L is 2-hydroxy-1-naphthaldehyde.

[0005] In some embodiments, the rare earth-based magnet material has a structure of five Gd ions, twelve deprotonated ligands L, two m 3-OH ion, two coordinated water molecules, five acetonitrile molecules, five ethanol molecules, one chloride ion, eleven free water molecules and one chloride ion; five Gd ions through two m The 3-OH groups are connected to form a double triangle pentanuclear structure with common vertices, and each Gd ion is an eight-coordinated configuration.

[0006] In some specific embodiments, [Gd5(L) 12 ( m In the structure of [3-OH)2(H2O)2]Cl·5EtOH·5CH3CN·11H2O, the bond length of Gd(III)-O formed by Gd(III) and oxygen O is between 2.238(8)-2.514(8)Å, and the bond angle of O-Gd(III)-O is between 66.8(3)°-155.6(3)°.

[0007] In some embodiments, the chemical formula of the rare earth-based magnet material is C 152 H 157 C5D 44 , molecular weight is 3509.63.

[0008] In some embodiments, the rare earth-based magnet material belongs to the tetragonal system. Space group, the unit cell parameters of the rare earth-based magnet material are: a =17.9517(2)Å, b =17.9517(2)Å, c =51.4044(8)Å, α= 90.00º, β= 90.00º, c= 90.00º.

[0009] In some embodiments, the rare earth-based magnet material is prepared by the following method: Gd(ClO4)3·6H2O, 2-hydroxy-1-naphthaldehyde and 2-amino-2-methyl-1,3-propanediol are weighed and dissolved in an organic solvent to obtain a mixed solution, and the solution is placed at room temperature to obtain [Gd5(L) 12 ( m 3-OH)2(H2O)2]Cl·5EtOH·5CH3CN·11H2O.

[0010] The present application also provides a method for preparing a rare earth-based magnet material, comprising the following steps: Weigh Gd(ClO4)3·6H2O, 2-hydroxy-1-naphthaldehyde and 2-amino-2-methyl-1,3-propanediol and dissolve them in an organic solvent to obtain a mixed solution, which is then placed at room temperature to obtain [Gd5(L) 12 ( m 3-OH)2(H2O)2]Cl·5EtOH·5CH3CN·11H2O.

[0011] The present application synthesizes gadolinium magnetic materials at room temperature, and the preparation path has low energy consumption and low pollution, which provides a new preparation strategy for metal complexes and solves the problem that the self-assembly of magnets in the prior art mostly relies on high temperature and high pressure.

[0012] In some embodiments, the organic solvent comprises anhydrous ethanol and acetonitrile in a volume ratio of 1:(2-3), such as a volume ratio of anhydrous ethanol and acetonitrile in the organic solvent is 1:2 or 1:3.

[0013] In some embodiments, the mixed solution is allowed to stand at room temperature for 5 h to 24 h.

[0014] In some embodiments, the molar ratio of Gd(ClO4)3·6H2O, 2-hydroxy-1-naphthaldehyde and 2-amino-2-methyl-1,3-propanediol is 0.1:0.4:0.2.

[0015] The embodiments of the present application also provide the use of the above-mentioned rare earth-based magnet material or the rare earth-based magnet material prepared by the above-mentioned method for preparing the rare earth-based magnet material in the preparation of magnetic refrigeration materials and magnetic resonance contrast agents.

[0016] Beneficial effects: The present application provides a rare earth-based magnet material, a preparation method and an application. The chemical formula of the rare earth-based magnet material of the present application is: [Gd5(L) 12 ( m 3-OH)2(H2O)2]Cl·5EtOH·5CH3CN·11H2O, wherein L is 2-hydroxy-1-naphthaldehyde. The rare earth-based magnet material of the present application can be used as a magnetic refrigeration material and a magnetic resonance imaging contrast agent. By taking advantage of the high number of nuclei, it can achieve better imaging effects at lower doses, improve image contrast and clarity, extend the imaging window, and thus facilitate comprehensive diagnosis and reduce potential toxicity. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a molecular structure diagram of the rare earth-based magnet material prepared in Example 1 of the present invention; Figure 2 is a molecular skeleton diagram of the rare earth-based magnet material prepared in Example 1 of the present invention; Figure 3 is a skeleton structure diagram of the rare earth-based magnet material prepared in Example 1 of the present invention; Figure 4 The rare earth-based magnet material prepared in Example 1 of the present application xM、xMT Temperature T Change curve chart; Figure 5 The rare earth-based magnet material prepared in Example 1 of the present application at different temperatures MH picture; Figure 6 The rare earth-based magnet material prepared in Example 1 of the present application right T Change curve; Figure 7 is an infrared spectrum of the rare earth-based magnet material prepared in Example 1 of the present application; Figure 8 This is a magnetic resonance imaging performance diagram of the rare earth-based magnet material prepared in Example 1 of the present application. DETAILED DESCRIPTION

[0018] Example 1: [Gd5(L) 12 ( m Preparation of 3-OH)2(H2O)2]Cl·5EtOH·5CH3CN·11H2O Gd(ClO4)3·6H2O (0.1mmol, 0.0451g), 2-hydroxy-1-naphthaldehyde (0.4mmol, 0.0688g), and 2-amino-2-methyl-1,3-propanediol (0.2mmol, 0.0210g) were accurately weighed in a lead-free glass bottle in sequence, and 1.5mL of acetonitrile and 0.5mL of anhydrous ethanol were added. The mixture was shaken thoroughly to ensure uniform mixing to form a uniform solution, which was exposed to air at room temperature and left statically for 10h to obtain [Gd5(L) 12 ( m 3-OH)2(H2O)2]Cl·5EtOH·5CH3CN·11H2O.

[0019] Example 2: Characterization and performance measurement of the rare earth-based magnet material prepared in Example 1 (1) Structural characterization Select single crystals with good texture and no cracks, and use SuperNova X-ray single crystal diffractometer to analyze the single crystals on graphite monochromator. Mo- Under Kα radiation (λ=0.7107Å), 293(2)K conditions, at a specific i Range f-o Diffraction points were collected in a scanning mode for single crystal structure analysis and correction. All compounds were solved by direct method and refined by full matrix least squares method using ShelXL-2014 and SHELXL packages. All non-hydrogen atoms were refined by direct method. Detailed crystal determination data are shown in Table 1, and specific crystal bond length and bond angle tables are shown in Table 2. Molecular structure is shown in Figure 1~Figure 3 shown.

[0020] Table 1 Crystal determination data of rare earth-based magnet materials

[0021] Among them, Data in Table 1 represents the number of independent diffraction points involved in the correction, Restrains represents the number of restrictions used in the correction process, and parameters represents the number of variables involved in the correction.

[0022] Table 2 Bond lengths and angles of rare earth-based magnet materials

[0023] (2) Determination of magnetic properties The rare earth-based magnet material prepared in Example 1 was subjected to variable temperature AC magnetic susceptibility measurement in a 1000 Oe external DC magnetic field and a temperature range of 2 K to 300 K. The test data were plotted as x M T and x M TT The results are as follows Figure 4 When the temperature is at room temperature, the rare earth-based magnet material x M T The value is 38.19cm 3 Kmol -1 , and the theory of five independent Gd(III) ions x M T The values ​​are very close. The temperature is between 300K and 50K. x M T Keep basically unchanged, and the temperature continues to drop x M T The value drops rapidly and finally reaches a minimum value of 27.67 cm at a temperature of 2 K. 3 Kmol -1 , the molar magnetic susceptibility of rare earth-based magnet materials in the entire test environment x M It directly shows a negative correlation with temperature. At the same time, the field-dependent magnetization intensity of rare earth-based magnet materials was tested under the condition of temperature range of 2K~8K. The curves did not overlap, and the increase was obvious in low field environment and slightly changed in high field environment. When the external magnetic field was 50KOe and the temperature was 2K, the magnetization intensity of rare earth-based magnet materials reached 30.76 Nm B , which is quite consistent with its theoretical value. According to Maxwell's relationship, the magnetic entropy of rare earth-based magnet materials changes and the magnetic entropy (-D S m ) to temperature T At 2K, H=5T, The actual value is 9.76 Jmol -1 K -1 , this complex The value is close to that of the complex containing five Gd(III) ions. The above results, combined with the properties of high spin state and zero orbital angular momentum of the Gd(III) complex, indicate that the rare earth-based magnet material prepared in Example 1 of the present application can be used as a magnetic refrigeration material.

[0024] like Figure 2 As shown, the rare earth-based magnet material prepared in Example 1 at different temperatures MH Figure, from Figure 5 It can be seen that there is no overlap in the curves. The increase is obvious under low field conditions and there is a slight change under high field conditions. At 2K, the rare earth-based magnet material reaches 30.72 at 50KOe. Nm B, which is very close to the theoretical value. Figure 6 As shown, the rare earth-based magnet material prepared in Example 1 right T Change curve, as can be seen from the figure, at 2K, H=5T, The actual value is 9.76 Jmol -1 K -1 ,this The values ​​are similar to those of the complex containing five Gd(III) ions.

[0025] (4) Infrared spectroscopy analysis like Figure 7 As shown, the infrared spectrum of the rare earth-based magnet material prepared in Example 1 is Figure 7 The results show that the absorption peak of the rare earth-based magnet material prepared in Example 1 is at 3416 cm -1 It is relatively wide and long near 1614cm. It is believed that this segment belongs to the signal peak generated by the stretching vibration of rare earth-based magnet materials or water molecules in the environment. -1 There is a sharp peak at 1175cm, which is the signal peak generated by the stretching vibration of the C=C conjugated double bond in the benzene ring. -1 There is a weaker peak, which belongs to the signal peak generated by the CO stretching vibration of phenolic hydroxyl group.

[0026] (5) Magnetic resonance imaging performance analysis The central atom Gd of the rare earth-based magnetic material prepared in Example 1 is a paramagnetic metal. Therefore, whether the rare earth-based magnetic material prepared in Example 1 can be used as a GBCA (gadolinium contrast agent) is considered. Therefore, a 0.5T magnetic resonance scanner is used to measure the performance. The results are as follows: Figure 8 As shown. The rare earth-based magnet material prepared in Example 1 has a magnetic field strength of 0.5 T. T 1 weighted MR grayscale image and the corresponding pseudo-color darkening both show significant concentration dependence. The transverse relaxation rate ( R 1) and longitudinal relaxation rate ( R 2) are 2.74mM respectively -1 s -1 and 3.08mM -1 s -1 , according to the longitudinal relaxation enhancement ratio formula ( R 2 / R 1) The result is 1.12. In summary, the rare earth-based magnet material prepared in Example 1 has the properties of a positive contrast agent and can be used as an ideal gadolinium contrast agent (GBCA) material.

[0027] The above is a detailed introduction to a rare earth-based magnet material, preparation method and application provided in the embodiments of the present application. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method of the present application and its core idea; at the same time, for technical personnel in this field, according to the idea of ​​the present application, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A rare earth-based magnet material, characterized in that: The chemical formula of the rare earth-based magnet material is: [Gd5(L) 12 ( μ 3-OH)2(H2O)2]Cl·5EtOH·5CH3CN·11H2O, wherein L is 2-hydroxy-1-naphthaldehyde.

2. The rare earth-based magnet material according to claim 1, characterized in that: The rare earth-based magnet material has a structure of five Gd ions, twelve deprotonated ligands L, and two μ 3-OH ion, two coordinated water molecules, five acetonitrile molecules, five ethanol molecules, one chloride ion, eleven free water molecules and one chloride ion; five Gd ions through two μ The 3-OH groups are connected to form a double triangle pentanuclear structure with common vertices, and each Gd ion is an eight-coordinated configuration.

3. The rare earth-based magnet material according to claim 1, characterized in that: The rare earth-based magnet material belongs to the tetragonal system. Space group, the unit cell parameters of the rare earth-based magnet material are: a =17.9517(2)Å, b =17.9517(2)Å, c =51.4044(8)Å, α= 90.00º, β= 90.00º, γ= 90.00º.

4. The rare earth-based magnet material according to claim 1, characterized in that: The rare earth-based magnet material is prepared by the following method: Gd(ClO4)3·6H2O, 2-hydroxy-1-naphthaldehyde and 2-amino-2-methyl-1,3-propanediol are weighed and dissolved in an organic solvent to obtain a mixed solution, and the mixed solution is placed at room temperature to obtain [Gd5(L) 12 ( μ 3-OH)2(H2O)2]Cl·5EtOH·5CH3CN·11H2O.

5. The method for preparing a rare earth-based magnet material according to claim 1, characterized in that: The following steps are involved: Weigh Gd(ClO4)3·6H2O, 2-hydroxy-1-naphthaldehyde and 2-amino-2-methyl-1,3-propanediol and dissolve them in an organic solvent to obtain a mixed solution, which is then placed at room temperature to obtain [Gd5(L) 12 ( μ 3-OH)2(H2O)2]Cl·5EtOH·5CH3CN·11H2O.

6. The method for preparing a rare earth-based magnet material according to claim 5, characterized in that: The organic solvent includes anhydrous ethanol and acetonitrile in a volume ratio of 1:(2-3).

7. The method for preparing a rare earth-based magnet material according to claim 5, characterized in that: The mixed solution is allowed to stand at room temperature for 5 h to 24 h.

8. The method for preparing a rare earth-based magnet material according to claim 5, characterized in that: The molar ratio of Gd(ClO4)3·6H2O, 2-hydroxy-1-naphthaldehyde and 2-amino-2-methyl-1,3-propanediol is 0.1:0.4:0.

2.

9. Use of the rare earth-based magnet material as claimed in any one of claims 1 to 4 or the rare earth-based magnet material prepared by the method for preparing the rare earth-based magnet material as claimed in any one of claims 5 to 8 in preparing magnetic refrigeration materials and magnetic resonance imaging contrast agents.

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