A rare earth-based magnet material, preparation method and application

Abstract

This application belongs to the technical field of magnetic functional materials. This application discloses a rare earth-based magnet material, a preparation method and an application. The chemical formula of the rare earth-based magnet material of this application is: [Gd5(L) 12 ( μ 3-OH)2(H2O)2]Cl·5EtOH·5CH3CN·11H2O, where L is 2-hydroxy-1-naphthaldehyde. The rare earth-based magnet material of this application can be used as a magnetic refrigeration material and a magnetic resonance imaging contrast agent. By taking advantage of the high nuclear number, 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.

Description

Technical Field

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

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

[0003] Object of the Invention: This application provides a rare earth-based magnet material, a preparation method and an application thereof. The rare earth-based magnet material of this application can be used in the preparation of magnetic resonance contrast agents, solving the defects of poor imaging effects and unclear contrast of existing contrast agents in the prior art.

[0004] Technical Solution: An embodiment of this application provides a rare earth-based magnet material, and the chemical formula of the rare earth-based magnet material is: [Gd 5 (L) 12 ( μ 3 -OH) 2 (H 2 O) 2 Cl·5EtOH·5CH 3 CN·11H 2 O, where L is 2-hydroxy-1-naphthaldehyde.

[0005] In some embodiments, the structure of the rare earth-based magnet material is composed of five Gd ions, twelve deprotonated ligands L, two μ 3 -OH ions, two coordinated water molecules, five acetonitrile molecules, five ethanol molecules, eleven free water molecules and one chloride ion; the five Gd ions are connected by two μ 3 -OH to form a co-vertex double-triangle pentanuclear structure, and each Gd ion has an octahedral coordination configuration.

[0006] In some specific embodiments, [Gd 5 (L) 12 ( μ 3 -OH) 2 (H 2 O) 2 Cl·5EtOH·5CH 3 CN·11H 2In the O structure, the bond lengths of Gd(III)-O formed by Gd(III) and oxygen O are between 2.238(8) - 2.514(8) Å, and the bond angles of O-Gd(III)-O are 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 ClGd 5 O 44 , and the molecular weight is 3509.63.

[0008] In some embodiments, the rare earth-based magnet material belongs to the tetragonal crystal system, space group, and 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.

[0009] In some embodiments, the rare earth-based magnet material is prepared by the following method: Weigh Gd(ClO 4 ) 3 ·6H 2 O, 2-hydroxy-1-naphthaldehyde, and 2-amino-2-methyl-1,3-propanediol and dissolve them in an organic solvent to obtain a mixed solution. Let it stand at room temperature to obtain [Gd 5 (L) 12 ( μ 3 -OH) 2 (H 2 O) 2 Cl·5EtOH·5CH 3 CN·11H 2 O.

[0010] This application embodiment also provides a preparation method of a rare earth-based magnet material, including the following steps:

[0011] Weigh Gd(ClO 4 ) 3 ·6H 2 O, 2-hydroxy-1-naphthaldehyde, and 2-amino-2-methyl-1,3-propanediol and dissolve them in an organic solvent to obtain a mixed solution. Let it stand at room temperature to obtain [Gd 5 (L) 12 ( μ 3 -OH)2 (H 2 O) 2 Cl·5EtOH·5CH 3 CN·11H 2 O。

[0012] This application synthesizes gadolinium magnetic materials at room temperature. The preparation route has low energy consumption and low pollution, providing a new preparation strategy for metal complexes and solving the problem that the self-assembly of magnets in the prior art mostly depends on high temperature and high pressure.

[0013] In some embodiments, the organic solvent includes anhydrous ethanol and acetonitrile with a volume ratio of 1:(2 - 3), such as the volume ratio of anhydrous ethanol to acetonitrile in the organic solvent being 1:2 or 1:3.

[0014] In some embodiments, the mixed solution is allowed to stand at room temperature for 5 h to 24 h.

[0015] In some embodiments, the molar ratio of Gd(ClO 4 ) 3 ·6H 2 O, 2-hydroxy-1-naphthaldehyde, and 2-amino-2-methyl-1,3-propanediol is 0.1:0.4:0.2.

[0016] This application embodiment also provides the application of the above rare earth-based magnet material or the rare earth-based magnet material prepared by the above preparation method of the rare earth-based magnet material in the preparation of magnetic refrigeration materials and magnetic resonance imaging contrast agents.

[0017] Beneficial effects: This 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 this application is: [Gd 5 (L) 12 ( μ 3 -OH) 2 (H 2 O) 2 Cl·5EtOH·5CH 3 CN·11H 2 O, where L is 2-hydroxy-1-naphthaldehyde. The rare earth-based magnet material of this application can be used as a magnetic refrigeration material and a magnetic resonance imaging contrast agent. Utilizing the advantage of a high nuclear number, 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

[0018] Figure 1 is the molecular structure diagram of the rare earth-based magnet material prepared in Example 1 of the present invention;

[0019] Figure 2It is the molecular skeleton diagram of the rare earth-based magnet material prepared in Example 1 of the present invention;

[0020] Figure 3 It is the skeleton structure diagram of the rare earth-based magnet material prepared in Example 1 of the present invention;

[0021] Figure 4 It is the χM, χMT of the rare earth-based magnet material prepared in Example 1 of this application with respect to temperature T variation curve graph;

[0022] Figure 5 It is the M-H graph of the rare earth-based magnet material prepared in Example 1 of this application at different temperatures;

[0023] Figure 6 It is the of the rare earth-based magnet material prepared in Example 1 of this application with respect to T variation curve;

[0024] Figure 7 It is the infrared spectrum graph of the rare earth-based magnet material prepared in Example 1 of this application;

[0025] Figure 8 It is the magnetic resonance imaging performance graph of the rare earth-based magnet material prepared in Example 1 of this application. Detailed implementation manners

[0026] Example 1: [Gd 5 (L) 12 ( μ 3 -OH) 2 (H 2 O) 2 Cl·5EtOH·5CH 3 CN·11H 2 O preparation

[0027] Accurately weigh Gd(ClO 4 ) 3 ·6H 2 O (0.1 mmol, 0.0451 g), 2-hydroxy-1-naphthaldehyde (0.4 mmol, 0.0688 g), 2-amino-2-methyl-1,3-propanediol (0.2 mmol, 0.0210 g) in a lead-free glass bottle in sequence, add 1.5 mL of acetonitrile and 0.5 mL of absolute ethanol, shake well to ensure uniform mixing to form a homogeneous solution, and let it stand statically in contact with air at room temperature for 10 h to obtain [Gd 5 (L) 12 ( μ 3 -OH) 2 (H2 O) 2 Cl·5EtOH·5CH 3 CN·11H 2 O。

[0028] Example 2: Characterization and property measurement of the rare earth-based magnet material prepared in Example 1

[0029] (1) Structure characterization

[0030] Select single crystals with good texture, no cracks and regular shape. Using a SuperNova X-ray single crystal diffractometer, under graphite monochromatized Mo- Kα radiation (λ = 0.7107 Å), 293(2)K conditions, in a specific θ range to φ-ω collect diffraction points in a scanning manner for single crystal structure analysis and refinement. All compounds are solved by the direct method and refined by full matrix least squares using the ShelXL-2014 and SHELXL program packages. All non-hydrogen atoms are refined using the direct method. The detailed crystal determination data are shown in Table 1, and the specific crystal bond lengths and bond angles are shown in Table 2. The molecular structure is as Figures 1 to 3 shown.

[0031] Table 1 Crystal determination data of rare earth-based magnet materials

[0032]

[0033] Among them, Data in Table 1 represents the number of independent diffraction points involved in the refinement, Restrains represents the number of restraints used in the refinement process, and parameters represents the number of variables involved in the refinement.

[0034] Table 2 Bond lengths and bond angles of rare earth-based magnet materials

[0035]

[0036] (2) Measurement of magnetic properties

[0037] The temperature-dependent AC susceptibility of the rare earth-based magnet material prepared in Example 1 was measured in the range of 2K to 300K with an applied DC magnetic field of 1000 Oe. The test data were plotted as χ M T and χ M T-T graphs, and the results are as Figure 4 shown. When the temperature is at room temperature, the χ M T value of the rare earth-based magnet material is 38.19 cm 3Kmol -1 , is very close to the theoretical χ M T values of five independent Gd(III) ions. Between 300K and 50K, χ M T remains basically unchanged. As the temperature continues to drop χ M T the value drops rapidly and finally reaches a minimum value of 27.67 cm at a temperature of 2K 3 Kmol -1 . In the entire test environment, the molar magnetic susceptibility of the rare earth-based magnet material χ M directly shows a negative correlation with temperature. At the same time, the field-dependent magnetization intensity of the rare earth-based magnet material was tested under the condition of a temperature range of 2K - 8K. The curves did not overlap, and the increase was obvious in the low-field environment and slightly changed in the high-field environment. When the external magnetic field is 50KOe and the temperature is 2K, the magnetization intensity of the rare earth-based magnet material reaches 30.76 Nμ B , which is in good agreement with its theoretical value. According to the Maxwell relationship, based on the magnetic entropy change of the rare earth-based magnet material, the magnetic entropy (-D S m ) versus temperature T curve is plotted. At 2K and H = 5T, the actual value of is 9.76 Jmol -1 K -1 . The value of this complex is close to that of the complex containing five Gd(III) ions. Combining the above results with the high-spin state and zero orbital angular momentum properties of the Gd(III)-containing complex, the rare earth-based magnet material prepared in Example 1 of this application can be used as a magnetic refrigeration material.

[0038] As Figure 2 shown, for the rare earth-based magnet material prepared in Example 1 at different temperatures M-H graph, as can be seen from Figure 5 , the curves do not overlap, and the increase is obvious under low-field conditions and slightly changed under high-field conditions. At a temperature of 2K, the rare earth-based magnet material reaches 30.72 Nμ B at 50KOe, which is very close to the theoretical value. As Figure 6 shown, for the versus T change curve of the rare earth-based magnet material prepared in Example 1, as can be seen from the figure, at 2K and H = 5T, The actual value is 9.76 J / mol -1 K -1 , this value is similar to that of the complex containing five Gd(III) ions.

[0039] (4)Infrared spectroscopy analysis

[0040] As Figure 7 shown, the infrared spectrum of the rare earth-based magnet material prepared in Example 1. From Figure 7 the results, it can be seen that the absorption peak of the rare earth-based magnet material prepared in Example 1 is relatively broad and long around 3416 cm -1 . It is considered that this section belongs to the signal peak generated by the stretching vibration of water molecules in the rare earth-based magnet material or the environment. There is a sharp peak at 1614 cm -1 , which is the signal peak generated by the stretching vibration of the C=C conjugated double bond in the benzene ring. There is a peak with relatively weak signal at 1175 cm -1 , which belongs to the signal peak generated by the stretching vibration of the phenolic hydroxyl C-O.

[0041] (5)Magnetic resonance imaging performance analysis

[0042] The central atom Gd of the rare earth-based magnet material prepared in Example 1 is a paramagnetic metal. Therefore, it is considered whether the rare earth-based magnet material prepared in Example 1 can become a GBCA (gadolinium-based contrast agent). So, a 0.5T magnetic resonance scanner was used for performance measurement, and the results are as Figure 8 shown. When the rare earth-based magnet material prepared in Example 1 is at 0.5T, T 1 weighted MR gray-scale images and the corresponding pseudo-color darkening both significantly show concentration dependence. The transverse relaxation rate ( R 1 ) and longitudinal relaxation rate ( R 2) of the rare earth-based magnet material prepared in Example 1 are 2.74 mM -1 s -1 and 3.08 mM -1 s -1 respectively. According to the longitudinal relaxation enhancement ratio formula ( R 2 / R 1 ), the result is 1.12. In summary, it shows that 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-based contrast agent (GBCA) material.

[0043] The above has introduced in detail a rare earth-based magnet material, a preparation method and an application provided by the embodiments of the present application. Specific examples are used herein to elaborate on the principle and implementation manner of the present application. The description of the above embodiments is only used to help understand the method and its core idea of the present application; at the same time, for those skilled in the art, according to the idea of the present application, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to 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; the structure of the rare earth-based magnet material is five Gd ions, twelve deprotonated ligands L, two μ 3-OH ion, two coordinated water molecules, five free ethanol molecules, five free acetonitrile molecules, eleven free water molecules and one free chloride ion; five Gd ions are connected by 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.

2. 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.

3. 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.

4. 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.

5. The method for preparing a rare earth-based magnet material according to claim 4, characterized in that: The organic solvent includes anhydrous ethanol and acetonitrile in a volume ratio of 1:(2-3).

6. The method for preparing a rare earth-based magnet material according to claim 4, characterized in that: The mixed solution is allowed to stand at room temperature for 5 h to 24 h.

7. The method for preparing a rare earth-based magnet material according to claim 4, 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.

8. Use of the rare earth-based magnet material as claimed in any one of claims 1 to 3 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 4 to 7 in the preparation of magnetic refrigeration materials and magnetic resonance imaging contrast agents.

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