Metallofullerene monomolecular magnet material and preparation method thereof

Abstract

The invention provides a metallofullerene monomolecular magnet material and a preparation method thereof. The metallofullerene is a monomolecular magnet with a nanometer size, the hysteresis phenomenon can be observed at 23K or below, and the metallofullerene shows a good magnetic behavior. According to the metallofullerene molecule, a triethylamine reduction method is adopted to enrich a metallofullerene anion solution, and then the solution and an iodobenzene solvent are subjected to a derivatization reaction to obtain the corresponding phenyl derivative of the metallofullerene. The preparation method is simple, clear in structure, high in purity and good in reproducibility, and can be applied to researches of ultrahigh-density storage materials, quantum computing technologies, electron spinning and the like.

Description

Technical Field

[0001] The present invention belongs to the field of molecular-based magnetic materials, and particularly relates to a metal fullerene single-molecule magnet material and a preparation method thereof. Background Art

[0002] A single-molecule magnet (SMM) is a single molecule that macroscopically exhibits slow magnetic relaxation behavior, and its magnetism comes from the magnetic bistability of the molecule itself. The f-orbital electrons of rare-earth metal ions have relatively large magnetic moments and magnetic anisotropy, so rare-earth ions have attracted much attention in the field of single-molecule magnets. As a zero-dimensional nanostructured carbon material, fullerene has a special cavity structure that can embed metal ions or metal clusters to form metal fullerenes. Compared with traditional metal-organic complex single-molecule magnets, metal fullerene single-molecule magnets formed by embedding rare-earth ions in fullerenes have the advantages of simple coordination environment and high stability due to the protection of magnetic metal ions by the external carbon cage. However, the currently developed metal fullerene single-molecule magnets mainly face problems such as extremely low yield, complex preparation process, and difficult purification. Therefore, it is of great significance to study and develop new preparation and purification methods for metal fullerenes. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a single-molecule magnet material based on metal fullerene, with the chemical formula Dy2@C 80 -C6H5 and a relative molecular mass of 1362.

[0004] Another object of the present invention is to provide a preparation method for the above-mentioned metal fullerene single-molecule magnet material.

[0005] A preparation method for a metal fullerene single-molecule magnet material:

[0006] Using a graphite rod filled with metal oxide Dy2O3 and graphite powder as the anode and a pure graphite rod as the cathode, arc discharge is carried out in an arc furnace. The soot generated by the discharge is dispersed in an organic solvent mixed solution, heated under reflux, and the metal fullerenes contained in the soot are extracted. The extracted metal fullerenes are dissolved in iodobenzene and heated under reflux to obtain phenyl derivatives of metal fullerenes. Finally, the product is purified using high-performance liquid chromatography.

[0007] In the present invention, the molar ratio of the metal oxide Dy2O3 to graphite powder is 1:20.

[0008] In the present invention, the organic solvent mixed solution is preferably a mixed solution of toluene:acetone:triethylamine (volume ratio 30:20:1); the heating reflux extraction time is preferably 5 hours.

[0009] In the present invention, the heating reflux time of iodobenzene is preferably 5 hours.

[0010] Advantages of the present invention:

[0011] The present invention develops a method for synthesizing endohedral dysprosium fullerene phenyl derivatives, which cannot be synthesized by known methods. This metal fullerene derivative has excellent single-molecule magnet characteristics and shows hysteresis below 23 K. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is the mass spectrum of the embodiment described in the present invention.

[0013] Figure 2 It is the magnetization intensity curve of the embodiment described in the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0014] To make the preparation scheme of the present invention clearer and more understandable, the following is a detailed description in combination with the drawings and embodiments.

[0015] Embodiment:

[0016] Using a graphite rod filled with metal oxide Dy2O3 and graphite powder as the anode and a pure graphite rod as the cathode, the DC arc furnace is evacuated until 5 Pa, then the cathode and anode are connected, short-circuited at 100 A for 1 hour. After the vacuum degree drops below 5 Pa again, stop evacuating, and fill helium gas until the pressure in the furnace reaches 180 Torr, and perform arc discharge at 100 A current. After the discharge, collect the soot, disperse it in a mixed solution of toluene:acetone:triethylamine (volume ratio 30:20:1) and heat under reflux for 5 hours. During this process, the metal fullerene is reduced to a negative ion by triethylamine and extracted into the solution. Centrifuge and filter the extract, take the supernatant and evaporate to dryness, add iodobenzene solvent and heat under reflux for 5 hours for phenyl derivatization reaction. Then centrifuge and filter the solution again, take the supernatant and evaporate to dryness, dissolve it in toluene solution, and purify it using high-performance liquid chromatography to obtain Dy2@C 80 -C6H5 solution. Drop the solution on a 4 mm х 4 mm silicon wafer, and after the solvent dries, fix it on a special quartz rod for testing with a magnetic measurement system (MPMS3).

[0017] The characterization of the dysprosium-containing metal fullerene single-molecule magnet material (Dy2@C 80 -C6H5) prepared in this example is as follows:

[0018] For mass spectrometry testing, an AB Sciex 5800 laser desorption time-of-flight mass spectrometer is used to characterize the dysprosium-containing metal fullerene Dy2@C 80 -C6H5 in positive ion mode. As Figure 1 shown, it can be observed that Dy2@C appears at the position of m / z = 1362 80-C6H5 characteristic peak, proving that the compound is Dy2@C 80 -C6H5 molecule. The Dy2@C observed in the mass spectrum 80 signal comes from the fragments generated by the laser cleavage of Dy2@C 80 -C6H5.

[0019] Magnetic measurements were carried out using a magnetic measurement system (MPMS3). The test temperatures for magnetization were 5 K and 23 K, and the applied magnetic field was ±5 T. The magnetization curves are as Figure 2 shown. As the applied magnetic field strength increases, the magnetization at each temperature increases and finally tends to saturate. At the same time, the hysteresis loops at 5 K and 23 K do not close. This indicates that Dy2@C 80 -C6H5 has magnetic relaxation behavior in the temperature range of 5 - 23 K. Compared with the dysprosium-containing dimetallic fullerenes reported in the literature, the blocking temperature is relatively high, showing good single-molecule magnet behavior.

[0020] The above are only the embodiments of the present invention, and the description thereof is relatively specific and detailed, but it should not be used to limit the patent scope of the present invention. Any equivalent structural or equivalent process transformation made by using the content of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, shall be equally included in the patent protection scope of the present invention.

Claims

1. A metal-fullerene single-molecule magnet with the chemical formula Dy2@C 80 -C6H5 and a relative molecular mass of 1362.

2. The preparation method of the metal fullerene single-molecule magnet material as described in claim 1 includes the following steps: Using a graphite rod filled with metal oxide Dy2O3 and graphite powder as the anode and a pure graphite rod as the cathode, arc discharge is carried out in an arc furnace. The soot generated by the discharge is dispersed in a mixed organic solvent solution, and heated under reflux to extract the metal fullerenes contained in the soot. The extracted metal fullerenes are dissolved in iodobenzene and heated under reflux to obtain phenyl derivatives of the metal fullerenes. Finally, high performance liquid chromatography is used to purify the product.

3. The preparation method of the metal fullerene single-molecule magnet material according to claim 2, wherein: The molar ratio of the metal oxide Dy2O3 to the graphite powder is 1:

20.

4. The preparation method of the metal fullerene single-molecule magnet material according to claim 2, characterized in that: The mixed organic solvent solution is preferably a toluene / acetone / triethylamine mixed solution with a volume ratio of 30:20:1; the time for heating under reflux extraction is preferably 5 hours.

5. The preparation method of the metal fullerene single-molecule magnet material according to claim 2, wherein: The time for heating iodobenzene under reflux is preferably 5 hours.

6. The metal fullerene single-molecule magnet according to claim 1, characterized in that: It exhibits hysteresis below 23K temperature and has single-molecule magnet behavior.

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