A novel manganese tetranuclear structure metal complex, a preparation method and application thereof

Abstract

The application relates to a metal coordination compound, in particular to a novel manganese tetranuclear structure metal complex, a preparation method and application of the complex, the chemical general formula of the complex is [Mn2(mu3-OH)Mn 0.5 Mn 0.5 (tbac)2] n ·2H2O, wherein H3tbac is 1,3,5-tri (carboxymethoxy) benzene; the preparation method comprises the following steps: placing H3tbac in a reaction kettle, adding a mixed solvent, stirring at room temperature for 30 min, adding manganese acetate tetrahydrate, continuing to stir until completely dissolved, adjusting the pH value to 7-8, continuing to stir for 30 min, then sealing the reaction kettle and placing the reaction kettle in a constant-temperature reaction at 160 DEG C, cooling to room temperature after reaction, filtering, washing, and obtaining block-shaped yellow crystals, namely the novel manganese tetranuclear structure metal complex. The obtained complex has good thermal stability and magnetic properties, and provides a theoretical basis and experimental basis for in-depth research and development of Mn complex molecule-based magnetic materials.

Description

Technical Field

[0001] This invention relates to metal coordination compounds, and particularly to a novel manganese tetranuclear metal complex, its preparation method, and its applications. Background Technology

[0002] With the increasing demand for various high technologies, magnetic materials have gradually developed into modern magnetic storage materials, magnetic wave absorption materials, magnetic induction materials, and magnetic sensitive materials. Molecular-based magnets have advantages such as high transparency, non-conductivity, low density, ease of processing, high magnetic capacity, and low magnetic loss ratio. Furthermore, the wide variety of ligand designs allows for the creation of diverse molecular-based magnets. Moreover, by studying the relationship between the structure and properties of coordination compounds, the structure of ligands can be purposefully modified to improve the performance of the coordination compounds and enhance the magnetic properties of molecular-based magnets. These magnets are suitable for applications such as electromagnetic shielding materials, aerospace materials, information storage materials, and biocompatible materials.

[0003] Bistable molecular-based magnetic materials are currently a hot research topic in molecular-based magnetic materials, including temperature-responsive and externally magnetic field-responsive magnetic bistable materials. Spin-crossover complexes and single-molecule magnets are the most widely studied. Spin-crossover complexes can achieve bistable phenomena near room temperature, modulated by external factors such as temperature, pressure, and light radiation, making them the closest to practical applications of molecular-based magnetic materials. Therefore, they have potential applications in molecular switches, sensing, and information storage. Single-molecule magnets are nanoscale molecular magnetic materials with characteristics such as easy processing, low density, and chemical solubility. Furthermore, single-molecule magnets retain their magnetization after the removal of an external magnetic field and exhibit slow magnetic relaxation behavior, making them highly promising for applications in ultra-high-density information storage, quantum computing, and spintronics. Transition metals Co(II) and rare-earth metals Dy(III) possess unquenched orbital angular momentum and strong magnetic anisotropy, making them ideal carriers for constructing high-performance single-molecule magnets. In recent years, scientists have moved beyond simply studying spin-crossing and single-molecule magnets independently. Instead, they have opted to design and synthesize novel ligands to combine these two properties into spin-crossing-single-molecule magnet bifunctional complexes. Currently, reports on combining these two properties to synthesize spin-crossing-single-molecule magnet bifunctional complexes are rare, and there are no reports on using the flexible aromatic carboxylic acid 1,3,5-tris(carboxymethoxy)benzene (H3tbac), with its flexible coordination mode, as a directional ligand to construct novel molecular-based magnetic materials of Mn complexes. Summary of the Invention

[0004] The purpose of this invention is to provide a novel manganese tetranuclear metal complex, its preparation method, and its application, addressing the aforementioned problems.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A novel manganese tetranuclear metal complex with the general chemical formula [Mn2(μ3-OH)Mn 0.5 Mn 0.5 (tbac)2] n ·2H2O, wherein H3tbac = 1,3,5-tris(carboxymethoxy)benzene; the complex belongs to the triclinic crystal system, space group Pī, and each manganese ion is in a six-coordinated coordination environment, forming an octahedral configuration;

[0007] The method for preparing the novel manganese tetranuclear metal complex is characterized by comprising the following steps:

[0008] H3tbac was placed in a reaction vessel, a mixed solvent was added, and the mixture was stirred at room temperature for 30 minutes. Manganese acetate tetrahydrate was added, and the mixture was stirred until completely dissolved. The pH was adjusted to 7-8, and the mixture was stirred for another 30 minutes. The reaction vessel was then sealed and placed at 160°C for constant temperature reaction. After the reaction, the mixture was cooled to room temperature, filtered, and washed to obtain blocky yellow crystals, which is the novel manganese tetranuclear structure metal complex.

[0009] In the above preparation method, preferably, the molar ratio of H3tbac and manganese acetate tetrahydrate is 1:1.

[0010] In the above preparation method, preferably, the mixed solvent is a mixed solution of water and ethanol in a volume ratio of 9:4 or 2:1.

[0011] In the above preparation method, preferably, the pH value is adjusted using a triethylamine solution.

[0012] In the above preparation method, preferably, the constant temperature reaction time is 4-5 days.

[0013] This invention also provides the application of the novel manganese tetranuclear structure metal complex in the preparation of molecular-based magnetic materials.

[0014] In summary, due to the adoption of the above technical solution, the present invention has the following beneficial effects:

[0015] This invention selects 1,3,5-tris(carboxymethoxy)benzene (H3tbac), a flexible aromatic carboxylic acid with a flexible coordination mode, as a directional ligand and reacts it with manganese acetate tetrahydrate via a solvothermal method to generate a novel tetranuclear metal complex. The preparation method is simple, convenient, uses readily available raw materials, operates under mild conditions, and has a high yield. The obtained complex exhibits good thermal stability and magnetic properties. Magnetic studies show that the magnetic properties of the complex are characterized by antiferromagnetic coupling between adjacent metal ions within the cluster, providing a theoretical basis and foundation for the subsequent design and synthesis of molecular-based magnetic materials with special magnetic properties. Attached Figure Description

[0016] Figure 1 This is a crystal structure diagram of the novel manganese tetranuclear structure metal complex of the present invention.

[0017] Figure 2 This is a coordination polyhedron diagram of the central ion of the novel manganese tetranuclear structure metal complex of the present invention.

[0018] Figure 3 This is a three-dimensional packing diagram of the novel manganese tetranuclear structured metal complex of the present invention.

[0019] Figure 4 This is a thermogravimetric and micro-thermogravimetric curve of the novel manganese tetranuclear structure metal complex of the present invention.

[0020] Figure 5 This is a surface interaction force diagram of the novel manganese tetranuclear structured metal complex of the present invention.

[0021] Figure 6 This is a two-dimensional fingerprint map of the surface interaction of the novel manganese tetranuclear structured metal complex of the present invention.

[0022] Figure 7 The χ of the novel manganese tetranuclear structured metal complex of this invention m –T、χ m T-T curve graph.

[0023] Figure 8 The χm of the novel manganese tetranuclear structured metal complex of this invention -1 –T curve graph.

[0024] Figure 9 This is the M-H curve of the novel manganese tetranuclear structure metal complex of the present invention at a temperature T=2K.

[0025] Figure 10 This is an AC magnetic susceptibility curve of the novel manganese tetranuclear structure metal complex of the present invention. Detailed Implementation

[0026] To more clearly illustrate the present invention, the following specific embodiments will be used to further explain the invention.

[0027] This invention provides a novel manganese tetranuclear metal complex with the general chemical formula [Mn2(μ3-OH)Mn 0.5 Mn 0.5 (tbac)2] n ·2H₂O, wherein H₃tbac = 1,3,5-tris(carboxymethoxy)benzene; the crystal structure diagram of the complex is shown below. Figure 1 As shown, the coordination polyhedron diagram of the central ion of the complex is as follows: Figure 2 As shown, the three-dimensional packing diagram of the complex 1 is as follows. Figure 3 As shown.

[0028] In this embodiment, 1,3,5-tris(carboxymethoxy)benzene is used as a directional ligand and reacted with manganese acetate tetrahydrate via a solvothermal method to generate a novel tetranuclear metal complex.

[0029] This complex belongs to the triclinic crystal system with space group Pī. Each manganese ion is in a six-coordinated coordination environment, forming an octahedral configuration. The molecules are stacked to form a three-dimensional structure through ligand oxygen bridging and π··π interactions of the benzene ring.

[0030] The experimental instruments and reagents used in the embodiments of this invention are as follows:

[0031] Experimental Instruments: Agilent G8910A CCD single-crystal diffractometer (Agilent Technologies, USA), Perkin-Elmer 240Q elemental analyzer (PerkinElmer, USA), Spectrum 65 Fourier transform infrared spectrometer (PerkinElmer, USA), RF-5301PC fluorescence spectrophotometer (Shimadzu Corporation, Japan); XTL-220 microscope (Shanghai Tiansheng Instrument Co., Ltd.), UV-8000 ultraviolet-visible spectrophotometer (Shanghai Yuanxi Instrument Co., Ltd.), HQT-4 fully automatic microcomputer differential calorimeter (Beijing Hengjiu Scientific Instrument Factory), MPMS SQUID magnetometer magnetic measurement system (QuantumDesign, USA).

[0032] Experimental reagents: All chemical reagents and chemicals used in the experiment were analytical grade, including 1,3,5-tris(carboxymethoxy)benzene (Jinan Henghua Technology Co., Ltd.), manganese acetate tetrahydrate, triethylamine, sodium hydroxide, anhydrous ethanol, and DMF (Xilong Chemical Co., Ltd.).

[0033] In some embodiments of the present invention, a method for preparing the above-mentioned novel manganese tetranuclear structure metal complex is also provided, comprising the following steps: placing H3tbac in a reaction vessel, adding a mixed solvent, stirring at room temperature for 30 min, adding manganese acetate tetrahydrate, continuing to stir until completely dissolved, adjusting the pH value to 7-8, continuing to stir for 30 min, then sealing the reaction vessel and placing it at a constant temperature of 160°C for reaction, cooling to room temperature after reaction, filtering, washing, and obtaining blocky yellow crystals, i.e., the novel manganese tetranuclear structure metal complex.

[0034] In the above preparation method, preferably, the molar ratio of H3tbac and manganese acetate tetrahydrate is 1:1.

[0035] In the above preparation method, preferably, the mixed solvent is a mixed solution of water and ethanol in a volume ratio of 9:4 or 2:1.

[0036] In the above preparation method, preferably, the pH value is adjusted using a triethylamine solution.

[0037] In the above preparation method, preferably, the constant temperature reaction time is 4-5 days.

[0038] To enable those skilled in the art to better understand the technical solution of this application, the technical solution of this application will be described in detail below with reference to specific embodiments.

[0039] I. Synthesis of Coordination Compounds

[0040] Example 1:

[0041] H3tbac (0.0750 g, 0.25 mmol) was placed in a 30 mL reactor, and a mixed solvent consisting of 9 mL water and 4 mL ethanol was added. The mixture was stirred at room temperature for 30 min. Manganese acetate tetrahydrate (0.0613 g, 0.25 mmol) was added, and stirring was continued for 1 h until completely dissolved. The pH was adjusted to 7 with triethylamine solution, and stirring was continued for 30 min. The reactor was then sealed and placed in a 160 °C incubator for 5 days. After the reaction, the mixture was cooled to room temperature, filtered, and washed to obtain clean, blocky yellow crystals. The yield was 0.081 g, with a yield of 71.6% (based on H3TB).

[0042] Example 2:

[0043] H3tbac (0.0750 g, 0.25 mmol) was placed in a 30 mL reaction vessel, and a mixed solvent consisting of 10 mL water and 5 mL ethanol was added. The mixture was stirred at room temperature for 30 min. Manganese acetate tetrahydrate (0.0613 g, 0.25 mmol) was added, and the mixture was stirred for another 1 h until completely dissolved. The pH was adjusted to 8 with triethylamine solution, and the mixture was stirred for another 30 min. The reaction vessel was then sealed and placed in a 160 °C incubator for 4 days. After the reaction, the mixture was cooled to room temperature, filtered, and washed to obtain clean, blocky yellow crystals.

[0044] II. Identification of Coordination Compounds

[0045] The blocky yellow crystals obtained in Examples 1 and 2 were characterized by infrared absorption spectroscopy (IR), elemental analysis, and X-ray single-crystal diffraction. The results are as follows:

[0046] Infrared data: IR (KBr): 3448, 1605, 1429, 1320, 1264, 1160, 1083, 941, 818, 732, 676, 590 cm⁻¹-1 .

[0047] The complex at 3448cm -1 The absorption peak is attributed to the hydroxyl (-OH) peak of the water molecule; at 1605 cm⁻¹ -1 The absorption peak at 1429 cm⁻¹ is a characteristic peak of the carbonyl group on the carboxyl group (C=O), while the characteristic peak of the benzene ring skeleton (C=C) appears at 1429 cm⁻¹. -1 1320cm -1 At 676cm -1 The Mn-O absorption peak at 818 cm⁻¹ indicates that the carbonyl group in the ligand is coordinated with the manganese ion during the reaction. The out-of-plane bending peak of CH on the benzene ring appears at 818 cm⁻¹. -1 The characteristic peak of the methyl group on the benzene ring is located at 732 cm⁻¹. -1 Complex 676cm -1 The presence of a Mn-O coordination characteristic peak indicates that the ligand has successfully coordinated with the metal ion.

[0048] Elemental analysis: C, 35.47; H, 2.86. Theoretical value (C) 24 H 23 Mn3O 21 , Mr=812.24): C, 35.49; H, 2.85.

[0049] Crystallographic data: The chemical formula of the complex is C 24 H 23 Mn3O 21 It belongs to the triclinic crystal system, space group P, and its crystallographic parameters, main bond lengths and bond angles are listed in Tables 1, 2 and 3, respectively.

[0050] Table 1. Crystallographic parameters of the coordination compounds

[0051] Table 1 Crystal data and structure refinements for complex

[0052]

[0053]

[0054] Note: [a]R1=Σ||F o |–|F c || / Σ|F o |.[b]wR2=[Σw(|F o 2 |–|F c 2 |) 2 / Σw(|F o 2 |)2 ] 1 / 2 .

[0055] Table 2. Partial bond lengths of the coordination compounds

[0056] Table 2 Selected bond lengths for complex

[0057]

[0058] Table 3 Partial bond angles of coordination compounds

[0059] Table 3 Selected bond angles[°]for complex

[0060]

[0061]

[0062] Note: (i)-x+2,-y+1,-z+1; (ii)-x+2,-y,-z+1; (iii)x,y+1,z; (iv)-x+2,-y+1,-z; (v)x,y ,z+1; (vi)x,y+1,z-1; (vii)-x+2,-y,-z; (viii)x,y-1,z; (ix)x,y-1,z+1; (x)x,y,z-1.

[0063] Figure 1 The crystal structure of the complex is as follows: Figure 1 It can be seen that the complex is composed of two Mn groups. II Two Mn III One bridging hydroxyl anion, two TBACs 3- The complex consists of ligands and two water molecules. In the structure of this complex, the four manganese ions have different occupancy rates: Mn1 and Mn3 have occupancy rates of 0.5, while Mn2 and Mn4 have occupancy rates of 1. Each manganese ion is in a six-coordinated coordination environment, forming an octahedral configuration. Mn1 and Mn3 have the same coordination configuration; taking Mn1 as an example, Mn1 is associated with the five oxygen atoms of the four polydentate ligands. It coordinates with a μ3-OH oxygen bridging atom (Mn1-O19=2.010(3), symmetry codes: (i)x+1,y,z; (ii)-x+2,-y,-z) to form a hexahedral MnO6 configuration. The coordination of Mn2 and Mn4 is the same. Taking Mn2 as an example, Mn2 coordinates with the four oxygen atoms of the four polydentate ligands. and two μ3-OH oxygen bridging atoms Symmetric codes: (iii) -x+2, -y, -z+1; (iv) x, y, z+1) coordinate to form a hexahedral MnO6 configuration.

[0064] Figure 2 This is the coordination polyhedron diagram of the manganese central ion in the complex. In the coordination octahedron where Mn1 is located, the equatorial plane is composed of O11, O19, and O14, respectively. i and O18 ii The optimal square plane equation is: -0.0263x + 0.8544y - 0.5189z = -1.1767. The average deviation of the four O atoms in the equatorial plane is... O1, O15 i These are two vertices of the octahedron, and their distances to the plane are respectively... and The distance by which the central manganese ion deviates from this plane is Therefore, both Mn1 and Mn3 form a twisted octahedral configuration. The equatorial plane of the coordination octahedron where Mn2 is located is formed by O4 and O4, respectively. ii O18 ii and O18 iv The optimal square plane equation is: -0.8738x + 0.0012y - 0.4863z = -13.7764. The average deviation of the four O atoms in the equatorial plane from the plane is 0. (O19, O19) iii These are two vertices of the octahedron, and their distances to the plane are both... Furthermore, the distance of the central manganese ion from the plane is also 0, so Mn2 and Mn4 form an octahedral configuration through coordination with oxygen atoms.

[0065] Figure 3 The diagram shows the three-dimensional stacking of the complex. The chains are orderly stacked into a three-dimensional structure through ligand oxygen bridging and π-π interactions of the ligand benzene ring.

[0066] III. Thermodynamic Stability Testing of Coordination Compounds

[0067] The thermal stability of the complex was determined using an HQT-4 fully automatic microcomputer differential calorimeter, with the pure phase crystals of the complex heated from 25°C to 900°C at a heating rate of 10°C / min under N2 atmosphere.

[0068] Figure 4The TG / DTG curves of the novel manganese tetranuclear metal complex synthesized in this invention are shown. It can be seen that the weight of each tetranuclear cluster remains essentially unchanged between 171 and 568 °C. From 171 °C, the entire framework structure of the complex begins to undergo pyrolysis, and all ligands are lost at 568 °C (theoretically 67.53%, actually 65.16%). The final residues are likely manganese oxides MnO2 and Mn3O4. A peak appears at approximately 378 °C on the differential thermogravimetric (DTG) curve, and this peak is very strong, indicating that the tetranuclear manganese clusters experience the greatest weight loss rate at high temperatures.

[0069] IV. Hirshfeld Surface Analysis

[0070] Using the crystal parameter CIF file of the complex as the data source, the distribution of Hirshfeld surface forces of the complex molecules was calculated using the CrystalExplorer 3.1 program. Different intermolecular interactions were visualized on the three-dimensional molecular surface of the crystal structure, and the Dnorm, Shape index and Curvedness diagrams were obtained. The 2D fingerprint was calculated to quantitatively analyze the nature and type of surface forces between molecules inside the crystal.

[0071] Figure 5 For the surface force diagram of the coordination compound, Figure 5 In the middle, the extent of the Dnorm surface on the left is The shape index and curvature s are respectively in and Within the range. Bright red spots on the Dnorm surface represent strong surface forces, such as hydrogen bonding and van der Waals forces, present in the complex molecules at that location. In the Shape Index diagram, bright yellow irregular shapes represent π··π interactions between molecules, corresponding to the benzene ring in the molecule. The Curvedness diagram measures the degree of surface deformation caused by intermolecular interactions in a crystal. Flat and sharp regions indicate lower and higher degrees of deformation, respectively. Different intermolecular forces around the molecule divide the surface deformation into different regions.

[0072] The results of quantitative analysis of the nature and type of surface forces between molecules within the crystal are summarized in a 2D fingerprint image, such as... Figure 6 In the complex molecule, O···H interactions account for 31.2% of the dominant interaction, and are evenly distributed in the central part of the fingerprint region. This indicates weak interactions such as close-range contact and van der Waals forces in the complex. H···H interactions account for 20.5%, which are conventional intramolecular hydrogen bonds in the complex molecule. The C···H / H···C ratio is 10.2%.

[0073] V. Magnetic Testing

[0074] Using the MPMS SQUID magnetometer (Quantum Design, USA), the relationship between molar magnetic susceptibility and temperature was determined for pure-phase crystals of the complex under a DC external magnetic field of 1000 Oe at temperatures of 2–300 K. The relationship between magnetization M and magnetic field strength H was also determined at 2 K. Furthermore, the relationship between AC magnetic susceptibility and frequency was determined at temperatures of 2–20 K and frequencies of 100 Hz and 997 Hz.

[0075] The χ² value obtained by scanning the pure-phase crystal of the complex within the temperature range of 2–300 K and under a DC external magnetic field of 1000 Oe was obtained. m –T and χ m T-T curve, such as Figure 7 As shown. For the tetranuclear manganese unit, χ m T is 10.93 cm at 300 K. 3 Kmol –1 This value is 6.94 cm⁻¹ greater than that of the non-interacting tetranuclear manganese unit. 3 Kmol –1 The high χ² value suggests orbital contributions from deformed octahedral Mn²⁺ ions. As temperature decreases, χ²... m The T value decreases, reaching a minimum of 8.10 cm at 1.99 K. 3 Kmol –1 As the temperature continues to decrease, χ m T rises rapidly, reaching a maximum value of 9.91 cm at 1.99 K. 3 Kmol –1 This magnetic behavior suggests that antiferromagnetic coupling exists between manganese ions within the tetranuclear cluster, and that at low temperatures, χ m The sudden increase in T may be due to zero-field splitting (ZFS) in the ground state, the Zeeman effect, or intermolecular antiferromagnetic interactions.

[26] 50K and above χ m –1 Following the Curie–Weiss law (χ=C / (T–θ)) for the T curve, a linear fit yields the Weiss constant θ=-11.08K and the Curie constant C=11.11cm. –1 Kmol –1 ,like Figure 8 As shown. The negative Weiss constant also suggests the existence of antiferromagnetic interactions between adjacent manganese ions within the cluster.

[0076] Figure 9The M-H curve of the complex at temperature T = 2 K shows that when the external field H is very small, the magnetization (M) increases almost linearly with H; after H > 2 T, the magnetization (M) increases slowly, reaching 9.38 Nβ·mol⁻¹ at 7 T. -1 Below the assumption g = 2, S T =5 when 10Nβ·mol -1 This suggests that M has not reached saturation or that some electrons occupy the excited state, the latter leading to a lower ground state spin.

[0077] Figure 10 The graph shows the AC magnetic susceptibility of the complex at temperatures ranging from 2 to 15 K and frequencies of 100 Hz and 997 Hz. This indicates that within this temperature range, neither the real nor imaginary parts of the AC magnetic susceptibility exhibit frequency dependence, nor do they show any peaks. These magnetic properties suggest that antiferromagnetic exchange interactions exist within the complex cluster.

[0078] The test results above show that this invention synthesizes a novel [Mn2(μ3-OH)Mn] structure using 1,3,5-tris(carboxymethoxy)benzene as a directional ligand. 0.5 Mn 0.5 (tbac)2] n The 2H₂O complex is a triclinic crystal with space group P. In its structural unit, four metal Mn ions coordinate with bridging μ₃-OH and ligand H₃tbac oxygen atoms to form an octahedral MnO₆ configuration. The molecules are orderly stacked into a three-dimensional structure through ligand oxygen bridging and π…π stacking interactions of the benzene rings within the ligands. The complex also exhibits good thermal stability. Hirshfeld surface analysis results show the presence of strong O…H and H…H hydrogen bonds on the complex surface, as well as intermolecular π…π interactions. Magnetic studies indicate that the complex's magnetic properties manifest as antiferromagnetic coupling between adjacent metal ions within the cluster, providing a theoretical basis for the subsequent design and synthesis of molecular-based magnetic materials with special magnetic properties.

[0079] The above description is a detailed description of the preferred embodiments of the present invention. However, the embodiments are not intended to limit the scope of the patent application of the present invention. All equivalent changes or modifications made under the technical spirit of the present invention should fall within the patent scope covered by the present invention.

Claims

1. A manganese tetranuclear metal complex, characterized in that, The general chemical formula of the complex is [Mn2( μ 3-OH)Mn 0.5 Mn 0.5 (tbac)2] n ·2H2O, where H3tbac = 1, 3, 5-tris(carboxymethoxy)benzene; The complex belongs to the triclinic crystal system and has a space group of [space group number missing]. P Each manganese ion is in a six-coordinated coordination environment, forming an octahedral configuration; the crystallographic parameters of the complex are shown in Table 1 below, the main bond lengths are shown in Table 2 below, and the main bond angles are shown in Table 3 below. Table 1 Crystallographic parameters of the coordination compounds ， R 1 = Σ|| F o | – | F c || / S| F o |; wR 2 = [Σ w (| F o 2 |– | F c 2 |) 2 / S w (| F o 2 |) 2 ] 1 / 2 Table 2. Main bond lengths of coordination compounds ， Table 3. Major bond angles of the complexes ， Symmetric code: (i) x+1, y, z; (ii) −x+2, −y, −z; (iii) −x+2, −y, −z+1; (iv) x, y,z+1; (v) −x+1, −y, −z+1; (vi) −x+1, −y, −z; (vii) x−1, y, z; (viii) x, y, z−1.

2. The method for preparing a manganese tetranuclear metal complex according to claim 1, characterized in that, Includes the following steps: H3tbac was placed in a reaction vessel, a mixed solvent was added, and the mixture was stirred at room temperature for 30 min. Manganese acetate tetrahydrate was added, and the mixture was stirred until completely dissolved. The pH was adjusted to 7-8, and the mixture was stirred for another 30 min. The reaction vessel was then sealed and placed at 160 °C for constant temperature reaction. After the reaction, the mixture was cooled to room temperature, filtered, and washed to obtain blocky yellow crystals, which are the manganese tetranuclear structure metal complexes. The mixed solvent is a mixed solution of water and ethanol in a volume ratio of 9:4 or 2:

1.

3. The preparation method according to claim 2, characterized in that: The molar ratio of H3tbac and manganese acetate tetrahydrate is 1:

1.

4. The preparation method according to claim 2, characterized in that: Adjust the pH value with triethylamine solution.

5. The preparation method according to claim 2, characterized in that: The constant temperature reaction time is 4-5 days.

6. The application of the manganese tetranuclear structure metal complex according to claim 1 in the preparation of molecular-based magnetic materials.

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