Mononuclear-binuclear eutectic rare earth magnetic complex and preparation method thereof

[0037] Embodiment one

[0038] A kind of mononuclear eutectic magnetic complex {[Tb(thd) 4 ][Tb 2 (thd) 6 (CH 3 COO)][Tmim] 2} The preparation method is specifically prepared according to the following steps:

[0039] 1. The 148.9 mg Tb(thd) 3 2H 2 O and 50.4 mg of TmimI were dissolved in 10 ml of n-pentane and stirred at room temperature for 10 minutes.

[0040] 2. Dissolve 3 mg of glacial acetic acid in 5 ml of n-pentane, slowly add it dropwise into the solution obtained in step 1, and stir and react for 10 minutes at room temperature.

[0041] 3. The reaction solution obtained in step 2 was stirred and reacted at 30°C for 60 minutes.

[0042] 4. Filter the reaction solution obtained in step 3, and slowly volatilize the filtrate at room temperature to obtain the colorless transparent rod-shaped crystals of the mononuclear eutectic magnetic complex.

[0043] The yield of the magnetic complex prepared in this example was 41.2%.

[0044] Embodiment two

[0045] A kind of mononuclear eutectic magnetic complex of the present embodiment {[Dy(thd) 4 ][Dy 2 (thd) 6 (CH 3 COO)][Tmim] 2} The preparation method is specifically prepared according to the following steps:

[0046] 1. Add 224.7 mg Dy(thd) 3 2H 2 O and 50.4 mg of TmimI were dissolved in 10 ml of n-pentane and stirred at room temperature for 10 minutes to obtain a mixed solution.

[0047] 2. Dissolve 3 mg of glacial acetic acid in 5 ml of n-pentane, and slowly add it dropwise into the mixed solution obtained in step 1, and stir and react for 10 minutes at room temperature.

[0048] 3. The reaction solution obtained in step 2 was continuously stirred and reacted at 50° C. for 120 minutes.

[0049] 4. Filter the reaction solution obtained in step 3, and slowly volatilize the filtrate at room temperature to obtain the colorless transparent rod-shaped crystals of the mononuclear eutectic magnetic complex.

[0050] The yield of the magnetic complex prepared in this example is 52.7%.

[0051] The complex prepared in this example is a mononuclear eutectic dysprosium complex constructed by β-diketone, tetramethylimidazolium and acetate, and its chemical formula is Dy 3 C 126 h 219 N 4 o 22 , the specific characteristics are as follows:

[0052] (1) Determination of crystal structure

[0053] The crystal structure of the complex of this example was determined by Bruker Smart Apex II CCD X-ray single crystal diffractometer. like figure 1 As shown, the complex crystallizes in the monoclinic system and belongs to the P2(1)/n space group, and the unit cell parameters are β=102.497(7)°, Z=4. An asymmetric unit contains a mononuclear Dy(III) structural unit [Dy(thd) 4 ], a dual-core Dy(III) structural unit [Dy 2 (thd) 6 (CH 3 COO)] and two imidazolium counter cations [Tmim] +. Among them, in [Dy(thd) 4 ], Dy(III) is surrounded by four thd ligands, in {DyO 8} in an eight-coordinated environment, while in the binuclear [Dy 2 (thd) 6 (CH 3 COO)] in the structural unit, Dy(III) ions all adopt {DyO 7}’s seven-coordination mode, two Dy(III) centers are linked by an acetate group.

[0054] (2) Infrared spectrum measurement

[0055] Use Thermo Nicolet iS10 infrared spectrometer to characterize the complex described in this example, the results are: 2952.25 (w), 2864.93 (w), 1588.49 (m), 1573.73 (m), 1538.05 (m), 1504.20 (m), 1451.25 (m), 1384.92(s), 1354.34(s), 1285.18(w), 1225.18(m), 117 6.20(w), 1138.25(m), 1024.18(w), 867.41(m), 792.94(w), 602.73(w), 47 3.14(m)( figure 2 ).

[0056] (3) Powder Diffraction Determination of Phase Purity

[0057] The phase purity of the colorless rod-shaped crystals of the complex obtained in this example was characterized by using a Bruker D8ADVANCE powder diffractometer. like image 3 As shown, the simulation curves were simulated using Mercury 3.10.1 software and single crystal structure data. The results show that the dysprosium complex has reliable phase purity, which provides guarantee for its application in molecular-based magnetic materials.

[0058] The static and dynamic magnetic properties of the mononuclear eutectic magnetic complexes prepared in this example:

[0059] The magnetic properties of the dysprosium complexes were determined by the Quantum Design MPMS-SQUID-VSM, a magnetic measurement system of a superconducting quantum interferometer. The test temperature of DC magnetic susceptibility is 2 ~ 300K, and the field strength is 1kOe. The test temperature of magnetization is 2K, 3K, 5K and 8K, and the field strength is 0~70kOe. The frequency range used for the imaginary part of the AC magnetic susceptibility and the real part of the AC magnetic susceptibility is 1 to 999 Hz, the temperature range is 1.8 to 6.2 K, and the field strength is zero.

[0060] like Figure 4 As shown, at room temperature, the DC magnetic susceptibility (χ M ) and temperature (T) product is 41.18cm 3 Kmol -1. The value of this product decreases slowly with decreasing temperature, and decreases rapidly below 20K, indicating that the rare earth ions in this single-molecule magnet have large unquenched orbital contributions and antiferromagnetic interactions between ions. Magnetization curve ( Figure 5 ) shows that when the field strength H is less than 10kOe, the magnetization M of the dysprosium complex increases rapidly with the increase of the magnetic field. Rare earth ions have strong magnetic anisotropy. In the case of an applied DC field of 0 Oe, the imaginary part of the AC magnetic susceptibility χ" of the dysprosium complex shows a significant temperature dependence ( Image 6 ) phenomenon, the corresponding Cole-Cole curve reflects a good semicircular distribution, and it can be fitted by the Debye function of a single relaxation process ( Figure 7 , the real part of the AC magnetic susceptibility in the figure is expressed by the symbol χ′). Based on the above phenomena, the rare earth complexes prepared by the present invention can exhibit typical slow relaxation behavior under zero field, have the characteristics of single-molecule magnets, and can be used as molecular-based magnetic materials in new high-density information storage devices (such as optical discs, hard disk, etc.) use.