Cobalt complex with ferromagnetic interaction and preparation method and application thereof

Abstract

The invention belongs to the technical field of transition metal coordination chemistry, and relates to a cobalt complex with ferromagnetic interaction and a preparation method and application thereof, the molecular formula of the cobalt complex is {Co (bim) 4 [N (CN) 2] 2} n, and bim is 1-allylimidazole. The synthesis method of {Co (bim) 4 [N (CN) 2] 2} n comprises the following steps: dissolving anhydrous cobalt chloride in absolute methanol, adding a bim ligand, stirring, dissolving sodium dicyanamide in water, adding into the solution, fully reacting, and filtering to obtain a red solution. And standing and volatilizing the solution in the air for several days to obtain the cobalt complex with ferromagnetic interaction. The preparation process is safe and simple, high in controllability and good in repeatability, and the prepared complex is good in stability and relatively high in purity. Ferromagnetic interaction exists among cobalt ions in the complex, and the complex can serve as a molecule-based magnetic material to be applied to the fields of novel high-density information storage equipment and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of transition metal complex coordination functional materials, and relates to a cobalt complex with ferromagnetic interaction, a preparation method and application thereof. Background Art

[0002] Coordination polymers, as an important form of supramolecular polymers, are based on the precise self-assembly process between metal ions and organic ligands. Coordination polymers with very regular infinite network structures are one of the specific manifestations of the application of crystal engineering in supramolecular compounds. Coordination polymers have novel structures and broad application prospects. [2] , which has aroused great research interest among many researchers.

[0003] As a special type of compound, the metal center of coordination polymers is figuratively called a "node", which highlights the core position of the metal center in the structure of coordination polymers. Transition metal ions are usually used as nodes of coordination polymers due to their unique electronic structure. The d orbitals of their electron-filled parts will show different orbital coupling modes under different coordination environments, which provides the possibility of designing coordination polymers with specific properties and applications. By adjusting the type and coordination environment of transition metal ions, the performance of coordination polymers can be precisely controlled. Different types of electronic structures are important factors that allow them to have a variety of different coordination geometric configurations.

[0004] Coordination polymers can exhibit a variety of magnetic properties due to their unique structure and composition. These properties have important research value and application prospects in materials science and physics. Magnetism is the macroscopic manifestation of the magnetic moment of atoms or ions in solid materials, usually including different magnetic properties such as ferromagnetism, ferromagnetism and ferrimagnetism. Ferromagnetism means that the magnetic moments of adjacent atoms or ions in a material tend to be arranged in the same direction under the interaction, so that under the action of an external magnetic field, the degree of directional arrangement of the magnetic moment will be enhanced until it reaches saturation. In order to achieve efficient magnetism, metal ions can enhance the magnetic coupling between metal ions by forming shorter bonds with small ligands (such as cyano or azide groups). Summary of the invention

[0005] The purpose of the present invention is to provide a cobalt complex with ferromagnetic interaction and a preparation method and application thereof. The complex is simple to synthesize and easy to operate, and can exist stably in the air.

[0006] In a first aspect of the present invention, there is provided a cobalt complex having ferromagnetic interaction, the molecular formula of which is {Co(bim) 4 [N(CN) 2 ] 2} n, wherein bim is 1-allylimidazole; the crystallographic parameters of the cobalt complex are: the crystal belongs to the monoclinic system, and the space group is P2 1 / n, the unit cell parameters are α=90°, β=103.3570(10)°, γ=90°; in each unit of the cobalt complex, the cobalt ion is respectively bonded with 4 bims and 2 [N(CN) 2 ] 2 - The ions are coordinated to form a hexacoordinate configuration; the configuration of the cobalt ions in each unit of the cobalt complex is a distorted octahedral configuration.

[0007] The second aspect of the present invention provides a method for preparing the above-mentioned cobalt complex with ferromagnetic interaction, the preparation method comprising the following steps:

[0008] S1. dissolving anhydrous cobalt chloride in anhydrous methanol, adding bim ligand, stirring to obtain a reaction solution;

[0009] S2. dissolving sodium dicyanamide in water and adding the solution to the reaction mixture to react. After the reaction is complete, filtering is performed to obtain a red solution.

[0010] S3. leaving the red solution to stand in the air to evaporate, thereby obtaining the cobalt complex having ferromagnetic interaction.

[0011] In some embodiments, in step S2 of the preparation method, the reaction temperature is room temperature.

[0012] In some embodiments, in step S3 of the preparation method, the standing time is 7-14 days.

[0013] In some embodiments, in the preparation method, CoCl 2 The molar ratio of BIM is 1:2. For every 0.5 mmol of CoCl 2 Corresponding to 2.0-2.5mmol of sodium dicyanamide.

[0014] In some embodiments, in the preparation method, for every 0.5 mmol of CoCl 2 Corresponds to 10-15 mL of anhydrous methanol.

[0015] In some embodiments, in the preparation method, every 2 mmol of sodium dicyanamide corresponds to 2 mL of water.

[0016] The cobalt ions in the complex prepared by the invention are in an octahedral coordination environment and present ferromagnetic interaction.

[0017] The third aspect of the present invention provides a use of the above-mentioned cobalt complex or the cobalt complex prepared by the above-mentioned preparation method in the preparation of a molecule-based magnetic material.

[0018] The fourth aspect of the present invention provides a use of the above-mentioned cobalt complex or the cobalt complex prepared by the above-mentioned preparation method in high-density information storage materials.

[0019] Compared with the prior art, the preparation method of the present invention is simple to operate, has good controllability and high reproducibility, and the obtained complex is stable in air at room temperature, has high purity, exhibits ferromagnetic interaction, and can be widely used in the preparation of molecular-based magnetic materials and high-density information storage materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The cobalt complex provided by the present invention {Co(bim) 4 [N(CN) 2 ] 2} n Coordination environment diagram of the cobalt ion in.

[0021] Figure 2 The cobalt complex provided by the present invention {Co(bim) 4 [N(CN) 2 ] 2} n Stacking structure diagram.

[0022] Figure 3 The cobalt complex provided by the present invention {Co(bim) 4 [N(CN) 2 ] 2} n Variable temperature magnetic susceptibility test diagram. DETAILED DESCRIPTION

[0023] The following is a clear and complete description of the technical solutions in the embodiments of the present invention in combination with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] The reagents used in the present invention are all commercially available and of analytical grade.

[0025] Example 1

[0026] Take 0.5mmol CoCl 2Dissolve in 10 ml of anhydrous methanol, add 1 mmol of bim, and stir. Weigh 2 mmol of sodium dicyanamide, dissolve in 2 ml of water, and quickly inject into the above solution. After reacting for 6 hours, filter to obtain a clear pink filtrate. Place the filtrate in the air and volatilize for one week to obtain purple-red block crystals, i.e., the cobalt complex {Co(bim) 4 [N(CN) 2 ] 2} n , with a yield of 61%.

[0027] Example 2

[0028] Take 0.5mmol CoCl 2 Dissolve in 10 ml of anhydrous methanol, add 1 mmol of bim, and stir. Weigh 2.5 mmol of sodium dicyanamide, dissolve in 2.5 ml of water, and quickly inject into the above solution. After reacting for 6 hours, filter to obtain a clear pink filtrate. The filtrate is placed in the air and evaporated for 10 days to obtain purple-red block crystals with a yield of 60%.

[0029] Example 3

[0030] Take 0.5mmol CoCl 2 Dissolve in 15 ml of anhydrous methanol, add 1 mmol of bim, and stir. Weigh 2 mmol of sodium dicyanamide, dissolve in 2 ml of water, and quickly inject into the above solution. After reacting for 6 hours, filter to obtain a clear pink filtrate. The filtrate is placed in the air and evaporated for two weeks to obtain purple-red crystals with a yield of 60%.

[0031] The cobalt complex {Co(bim) 4 [N(CN) 2 ] 2} n The samples were assayed as follows:

[0032] (1) Crystal structure determination

[0033] Single crystals of appropriate size were selected under a microscope, and the structure was tested at room temperature on a Bruker SMARTApex IICCD single crystal instrument using a graphite-monochromatized molybdenum target. The APEXII program was used to collect data and determine the unit cell. The structural data were normalized and absorption corrected using the SAINT and SADABS programs. The SHELXTL-97 program was used for structural analysis. All non-hydrogen atomic coordinates were obtained by the difference Fourier synthesis method, and the full matrix least squares method was used to correct the atomic coordinates and anisotropic temperature factors, and all hydrogen atoms were hydrogenated using theory. Figure 1 The cobalt complex {Co(bim) 4[N(CN) 2 ] 2} n Coordination environment diagram of the cobalt ion in. Figure 1 The structural picture proves that the cobalt ion is located in an octahedral coordination environment. Figure 2 The cobalt complex {Co(bim) 4 [N(CN) 2 ] 2} n The crystallographic data are shown in Table 1, and the coordination bond lengths are shown in Table 2.

[0034] Table 1: Cobalt complexes {Co(bim) 4 [N(CN) 2 ] 2} n Crystallographic data

[0035]

[0036]

[0037] Table 2: Cobalt complexes {Co(bim) 4 [N(CN) 2 ] 2} n Coordination bond length and bond angle data

[0038] <![CDATA[Co1-N2 1 ]]> 2.1171(14) Co1-N2 2.1171(14) <![CDATA[Co1-N5 2 ]]> 2.1562(16) <![CDATA[Co1-N5 3 ]]> 2.1562(16) Co1-N3 2.1429(15) <![CDATA[Co1-N3 1 ]]> 2.1429(15) <![CDATA[N2 1 -Co1-N2]]> 180.0 <h2 style=";text-align:left;direction:ltr"><![CDATA[N2 <h2 style=";text-align:left;direction:ltr"> 1 <h2 style=";text-align:left;direction:ltr"> -Co1-N3]]><h2 style=";text-align:left;direction:ltr"> 88.57(6) N3-Co1-N2 91.43(6) <h2 style=";text-align:left;direction:ltr"><![CDATA[N2 <h2 style=";text-align:left;direction:ltr"> 1 <h2 style=";text-align:left;direction:ltr"> -Co1-N3<h2 style=";text-align:left;direction:ltr"> 1 <h2 style=";text-align:left;direction:ltr"> ]]><h2 style=";text-align:left;direction:ltr"> 91.43(6) <![CDATA[N2-Co1-N3 1 ]]> 88.57(6) <![CDATA[N2-Co1-N5 2 ]]> 89.98(6) <![CDATA[N2 1 -Co1-N5 2 ]]> 90.02(6) <![CDATA[N2 1 -Co1-N5 3 ]]> 89.98(6) <![CDATA[N2-Co1-N5 3 ]]> 90.02(6) <h2 style=";text-align:left;direction:ltr"><![CDATA[N3 <h2 style=";text-align:left;direction:ltr"> 1 <h2 style=";text-align:left;direction:ltr"> -Co1-N3]]><h2 style=";text-align:left;direction:ltr"> 180.0 <![CDATA[N3 1 -Co1-N5 2 ]]> 88.89(7) <![CDATA[N3 1 -Co1-N5 3 ]]> 91.11(7) <![CDATA[N3-Co1-N5 3 ]]> 88.89(7) <![CDATA[N3-Co1-N5 2 ]]> 91.11(7) <![CDATA[N5 2 -Co1-N5 3 ]]> 180.0

[0039] Each cobalt ion is bound to four bim ligands and two [N(CN) 2 ] 2 - The coordination is carried out to form an octahedral coordination configuration, which is calculated by Shape software (Table 3).

[0040] Table 3: Cobalt complexes {Co(bim) 4 [N(CN) 2 ] 2} n CShM value

[0041] Configuration CShM value HP-6(Hexagonal) 32.366 PPY-6(Pentagonal Pyramid) 29.829 OC-6(octahedron) 0.022 TPR-6(Triangular Prism) 16.456 JPPY-6(Pentagonal Pyramid) 33.267

[0042] (2) Characterization of magnetic properties

[0043] The magnetic measurement adopts the superconducting quantum interference device Quantum Design MPMS SQUID VSM magnetic measurement system. The test temperature of DC magnetic susceptibility is 2.0~300K and the magnetic field is 1000Oe.

[0044] like Figure 3As shown, at 300K, the χ M T value is 3.01cm 3 K mol -1 , which is much larger than the corresponding χ when only the Co(II) ion spin is considered M T theoretical value (1.875cm 3 Kmol -1 ), which indicates that there is a large orbital angular momentum in the complex, and the magnetic anisotropy of the complex is increased through spin-orbit coupling. As the temperature decreases, the χ M The T value gradually decreases. When the temperature drops to around 50K, M The T value suddenly increases, indicating the existence of ferromagnetic interaction in the complex. When the temperature drops to 30K, χ M The T value continues to decrease until the temperature drops to 2.5K. M The T value dropped to the lowest value, which was 1.87cm 3 K mol -1 .

[0045] Based on the above phenomena, the cobalt complex prepared by the present invention has ferromagnetic interaction and can be used as a molecular-based magnetic material in high-density information storage devices.

[0046] Although some embodiments of the present general inventive concept have been shown and described, it will be appreciated by those skilled in the art that changes may be made to these embodiments without departing from the principles and spirit of the present general inventive concept, the scope of which is defined in the claims and their equivalents.

Claims

1. A cobalt complex with ferromagnetic interaction, the molecular formula of which is {Co(bim)4[N(CN)2]2} n , wherein bim is 1-allylimidazole; the crystallographic parameters of the cobalt complex are: the crystal belongs to the monoclinic system, the space group is P21 / n, and the unit cell parameters are α=90°, β=103.3570(10)°, γ=90°; In each unit of the cobalt complex, the cobalt ion is respectively connected with 4 bims and 2 [N(CN)2]2 - The ions are coordinated to form a six-coordinate configuration; The configuration of cobalt ions in each unit of the cobalt complex is a distorted octahedral configuration.

2. A method for preparing the cobalt complex according to claim 1, characterized in that: The preparation method comprises the following steps: S1. Dissolve anhydrous cobalt chloride in anhydrous methanol, add bim ligand, stir to obtain a reaction solution; S2. dissolving sodium dicyanamide in water and adding the solution to the reaction mixture to react. After the reaction is complete, filtering is performed to obtain a red solution. S3. leaving the red solution to volatilize in the air to obtain the cobalt complex having ferromagnetic interaction.

3. The preparation method according to claim 2, characterized in that: In step S2, the reaction temperature is room temperature.

4. The preparation method according to claim 2, characterized in that: In step S3, the standing time is 7-14 days.

5. The preparation method according to claim 2, characterized in that: The molar ratio of CoCl2 to BIM is 1:2, and every 0.5 mmol of CoCl2 corresponds to 2.0-2.5 mmol of sodium dicyanamide.

6. The preparation method according to claim 2, characterized in that: Every 0.5 mmol of CoCl2 corresponds to 10-15 mL of anhydrous methanol.

7. The preparation method according to claim 6, characterized in that: Every 2 mmol of sodium dicyanamide corresponds to 2 mL of water.

8. Use of the cobalt complex according to claim 1 or the cobalt complex prepared by the preparation method according to any one of claims 2 to 7 in the preparation of molecular-based magnetic materials.

9. Use of the cobalt complex according to claim 1 or the cobalt complex prepared by the preparation method according to any one of claims 2 to 7 in high-density information storage materials.

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