A pentanuclear rare earth-transition heterometallic complex, a preparation method and application thereof
By reacting chiral bisbenzimidazole ligands with rare earth and transition metals, pentanuclear rare earth-transition heterometallic complexes were synthesized, solving the problem of polynuclear or high-nuclear synthesis of traditional ligands. This resulted in complexes with a bow-shaped structure, which can be applied to the development of molecular magnetic materials and molecular memory materials.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- NANTONG UNIV
- Filing Date
- 2026-03-20
- Publication Date
- 2026-07-10
AI Technical Summary
Existing technologies make it difficult to synthesize rare earth-transition metal complexes with multinucleated structures, and traditional rigid ligands are prone to forming multinucleated or high-nucleation complexes during synthesis, affecting their spatial configuration and application value.
A pentanuclear rare earth-transition heterometallic complex was synthesized by reacting chiral bisbenzimidazole ligands with rare earth and transition metals under specific conditions via a room-temperature volatilization method, forming a bow-shaped metal framework structure.
A rare-earth-transition heterometallic complex with a five-core bow-knot structure was successfully prepared, enriching the structural types of the complex and providing a new direction for the preparation of molecular magnetic materials and molecular memory materials. It has potential value for high-density information storage and quantum computing applications.
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of rare earth-transition complex preparation technology, and relates to a pentanuclear rare earth-transition heterometallic complex, its preparation method and application. Background Technology
[0002] Rare earth ions possess characteristics such as a large number of electrons and high magnetic anisotropy parameters, and like transition metals, they exhibit excellent optical, electronic, and catalytic properties. Furthermore, rare earth ions may interact with transition metals via ferromagnetic or antiferromagnetic interactions, resulting in ordered magnetic arrangements and becoming potential molecular magnets. Therefore, rare earth-transition metal complexes have broad application prospects in high-density information storage, quantum computing, and the synthesis of multifunctional magnetic molecular materials, attracting increasing attention from researchers (Science, 2018, 362(6421): 1400-1403).
[0003] In the synthesis of rare earth-transition heterometallic complexes, the type of ligand not only directly affects the synthesis of the complexes but also influences their spatial configuration. Traditional rigid ligands are relatively small molecules, and when synthesized with metal salts, they tend to form polynuclear or even hypernuclear complexes. In contrast to traditional rigid ligands, chiral bisbenzimidazole ligands are typical tetradentate ligands, providing abundant coordination sites. They have unique application value in asymmetric catalysis, chiral recognition, and other fields, and can be used to construct optically active metal complexes. This makes metal complexes with these ligands potentially applicable in quantum computing, biosensing, and drug development (ACS Sustainable Chem. Eng., 2018, 6, 3723-3732). Summary of the Invention
[0004] The present invention aims to provide a pentanuclear rare earth-transition heterometallic complex, its preparation method and application. The pentanuclear rare earth-transition heterometallic complex contains three rare earth ions and two transition metal ions, forming a pentanuclear bow-shaped metal framework structure.
[0005] The technical solution provided by this invention is as follows:
[0006] A pentanuclear rare earth-transition heterometallic complex, wherein the pentanuclear rare earth-transition heterometallic complex belongs to the tetragonal crystal system and has the molecular formula: Dy3Ni2(L)3(HL)2(N3)4(H2O)2(CF3SO3)·2CH3OH·5H2O (complex 1, HL = partially deprotonated 1,2-di(1-methyl-1H-benzo[d]imidazol-2-yl)ethane-1,2-diol, L = fully deprotonated 1,2-di(1-methyl-1H-benzo[d]imidazol-2-yl)ethane-1,2-diol), space group P43212, and cell parameters: a = 25.8160(9) Å, b = 25.8160(9) Å, c = 47.3557(15) Å, α = 90°, β = 90°, γ = 90°, V = 31561(2) Å 3 .
[0007] A method for preparing the above-mentioned pentanuclear rare earth-transition heterometallic complex includes:
[0008] S1. Mix Dy(CF3SO3)3, NiCl2·6H2O and ligand H2L (1,2-di(1-methyl-1H-benzo[d]imidazol-2-yl)ethane-1,2-diol) in a certain proportion and dissolve them in CH3OH and H2O, and stir at room temperature for 5-10 min;
[0009] S2. Add Et3N and NaN3, stir at 80℃ for 10 h, and allow to stand to volatilize. After about two weeks, blue blocky crystals can be obtained. The blue blocky crystals are the pentanuclear rare earth-transition heterometallic complex.
[0010] The synthetic route for penta-nuclear rare earth-transition heterometallic complexes is shown in the following formula:
[0011]
[0012] In the above formula, complex 1 is Dy3Ni2(L)3(HL)2(N3)4(H2O)2(CF3SO3)·2CH3OH·5H2O.
[0013] Furthermore, in the above preparation method, the molar ratio of organic ligands H2L, Dy(CF3SO3)3, NiCl2·6H2O, NaN3, and Et3N is 2:1:1:2:6.
[0014] Furthermore, the volume ratio of CH3OH to H2O in the mixed solvent is 1:1.
[0015] Furthermore, the stirring time at room temperature is 5-10 minutes.
[0016] Furthermore, the amount of mixed solvent used is 4-8 mL for every 0.1 mmol of organic ligand H2L.
[0017] Furthermore, the amount of mixed solvent used is 6 mL for every 0.1 mmol of organic ligand H2L.
[0018] Furthermore, the heating reaction temperature is 70-90℃, and the reaction time is 8-12 h.
[0019] Furthermore, the settling and evaporation time is 12-16 days.
[0020] Furthermore, the heating reaction temperature is 80°C, and the reaction time is 10 h.
[0021] This invention also provides an application of the above-mentioned pentanuclear rare earth-transition heterometallic complex in molecular magnetic materials or molecular memory materials.
[0022] Compared with existing technologies, this invention utilizes chiral bisbenzimidazole ligands to successfully obtain a rare-earth-transition heterometallic complex with a pentanuclear bowtie structure via a room-temperature volatilization method. This preparation method is simple, uses readily available raw materials, and by designing the structure of chiral bisbenzimidazole ligands to react with rare-earth and transition metals to form rare-earth-transition heterometallic complexes, it enriches the structural types of rare-earth-transition complexes and provides a new direction for exploring their structural applications. The synthesized complex can be applied to the preparation of molecular magnetic materials or molecular memory materials, and has potential application value in fields such as high-density information storage and quantum computing. Attached Figure Description
[0023] These and / or other aspects and advantages of the present invention will become apparent and readily understood from the following description of preferred embodiments taken in conjunction with the accompanying drawings, in which:
[0024] Figure 1 Photographs of the products from Examples 1-4;
[0025] Figure 2 The molecular structure diagram of coordination compound 1;
[0026] Figure 3 Coordination environment diagram of the central metal ion in complex 1;
[0027] Figure 4 The infrared spectrum of complex 1;
[0028] Figure 5 Thermogravimetric diagram of complex 1;
[0029] Figure 6 The temperature-dependent magnetic susceptibility of complex 1 under a DC field of 1000 Oe;
[0030] Figure 7 Magnetization diagram of complex 1;
[0031] Figure 8 The reduced magnetization diagram of complex 1;
[0032] Figure 9 The real (χ') and imaginary (χ") AC magnetic susceptibility plots of complex 1 at 0 Oe;
[0033] Figure 10 The real (χ') and imaginary (χ") part AC magnetic susceptibility diagrams of complex 1 at 1000 Oe are shown. Detailed Implementation
[0034] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.
[0035] It should be noted that all reagents in the following examples were purchased directly from the market and were of analytical grade, without further purification before use.
[0036] Example 1: Preparation of Dy3Ni2(L)3(HL)2(N3)4(H2O)2(CF3SO3)·2CH3OH·5H2O
[0037] H₂L (0.1 mmol, 32.2 mg), Dy(CF₃SO₃)₃ (0.05 mmol, 30.5 mg), and NiCl₂·6H₂O (0.05 mmol, 11.9 mg) were dissolved in CH₃OH and H₂O. The solution was placed on a magnetic stirrer and stirred at room temperature for 5 min until homogeneous and free of precipitate. Then, NaN₃ (0.1 mmol, 6.5 mg) and Et₃N (0.3 mmol, 30.3 mg) were added, and the mixture was stirred at 80 °C for 10 h. The solution was then filtered and allowed to stand to evaporate. After about two weeks, blue blocky crystals were obtained, which is the target complex 1.
[0038] Example 2: H₂L (0.1 mmol, 32.2 mg), Dy(CF₃SO₃)₃ (0.05 mmol, 30.5 mg), and NiCl₂·6H₂O (0.05 mmol, 11.9 mg) were dissolved in CH₃OH and stirred at room temperature for 5 min to ensure a homogeneous solution without precipitate. Then, NaN₃ (0.1 mmol, 6.5 mg) and Et₃N (0.3 mmol, 30.3 mg) were added, and the mixture was stirred at 80 °C for 10 h. The solution was then filtered and allowed to stand to evaporate. After approximately two weeks, the target complex 1 failed to form.
[0039] Example 3: H₂L (0.1 mmol, 32.2 mg), Dy(CF₃SO₃)₃ (0.05 mmol, 30.5 mg), and NiCl₂·6H₂O (0.05 mmol, 11.9 mg) were dissolved in CH₃OH and H₂O. The solution was placed on a magnetic stirrer and stirred at room temperature for 5 min until the solution was homogeneous and free of precipitate. Then, Et₃N (0.3 mmol, 30.3 mg) was added, and the mixture was stirred at 80 °C for 10 h. The solution was filtered and allowed to stand to evaporate. After approximately two weeks, no crystals formed.
[0040] Example 4: H₂L (0.1 mmol, 32.2 mg), Dy(CF₃SO₃)₃ (0.05 mmol, 30.5 mg), and NiCl₂·6H₂O (0.05 mmol, 11.9 mg) were dissolved in H₂O and stirred on a magnetic stirrer at room temperature for 5 min to homogenize the solution. Then, NaN₃ (0.1 mmol, 6.5 mg) and Et₃N (0.3 mmol, 30.3 mg) were added, and stirring was continued at 80 °C for 10 h. The solution was filtered and allowed to stand to evaporate. After approximately two weeks, no crystals formed.
[0041] Figure 1 The figures are photographs of the products of Examples 1-4; wherein, (a) is a photograph of the product of Example 1, (b) is a photograph of the product of Example 2, (c) is a photograph of the product of Example 3, and (d) is a photograph of the product of Example 4.
[0042] Example 5: Crystal Structure Determination
[0043] High-quality single crystals were selected for structural determination. X-ray diffraction was performed using Xcalibur and Eos CCD single-crystal X-ray diffractometers, respectively. Mo Kα rays (λ = 0.71073 Å) monochromated by a graphite monochromator were used as the incident source for data collection and processing. All calculations were performed using the SHELXS-2014 and SHELXL-2014 software packages.
[0044] The asymmetric structural unit of coordination compound 1 is as follows Figure 2 As shown in the diagram. The coordination environment of Dy and Ni is shown in the diagram. Figure 3 As shown in Table 1, Dy1, Dy2, and Dy3 are all octagonal and exhibit a tetragonal antiprism coordination configuration. The coordinating atom of Dy1 is composed of two deprotonated L atoms. 2- Each ligand anion provides two O atoms (O3, O4, O7, O8) and one N atom (N5, N14), and another L atom. 2-The ligand anion provides two oxygen atoms (O9, O10), forming a {O6N2} coordination environment. Both Dy2 and Dy3 form a {O4N4} coordination environment with eight surrounding coordinating atoms. Taking Dy2 as an example, a deprotonated L... 2- The ligand anion provides one oxygen atom (O10), one nitrogen atom (N18); and another L... 2- The ligand anion provides only one oxygen atom (O3); one HL - The anion provides one oxygen atom (O2) and one nitrogen atom (N3); the two azide groups provide two nitrogen atoms (N30, N24); and the last oxygen atom (O12) is provided by a water molecule involved in coordination. Of the eight coordinating atoms in Dy3, O9 and N18 are provided by a deprotonated L... 2- The ligand anion provides the O7; O7 is provided by another L 2- The ligand anion provides; an HL - The anion provides one oxygen atom (O6) and one nitrogen atom (N11); the two azide groups provide two nitrogen atoms (N27, N21); the last oxygen atom (O11) originates from the water molecule involved in coordination. The Ni atoms in the complex are all six-coordinated octahedral, forming a coordination environment of {O3N3} (Table 2). The average distance between Dy and O in complex 1 is 2.33 Å, and between Dy and N is 2.51 Å. The bond angle between O and Cu is 66.1–165.4°, and between N and Dy is 74.1–163.6°. The bond angle between N and Cu is 81.30(18)–177.2(2).
[0045] Table 1. Calculated data on the partial coordination configurations of Dy1, Dy2, and Dy3 ions in coordination compound 1.
[0046]
[0047] Table 2 Calculated data on the coordination configuration of Ni ions in coordination compound 1
[0048]
[0049] Example 6: Infrared Spectroscopic Characterization
[0050] Complex 1 was characterized by infrared (FTIR) in the 4000-400 cm⁻¹ band. The results of the infrared spectral analysis are as follows: Figure 4 As shown. Complex 1 at 1620 cm. -1 The presence of a strong absorption peak, attributed to the C=C stretching vibration, indicates the presence of unsaturated bonds in the complex; the absorption peak is located at 3500–3100 cm⁻¹. -1 A strong absorption peak exists in the band, which is due to the stretching vibration of the NH bond; in the 1450-1650 cm⁻¹ band.-1 Several distinct absorption peaks were observed in the range, which are characteristic peaks caused by the stretching vibration of the benzene ring skeleton.
[0051] Example 7: Thermogravimetric Analysis
[0052] Thermogravimetric analysis results of complex 1 ( Figure 5 The results show that the complex gradually loses weight as the temperature increases. When the weight loss ratio of the complex reaches 5.1%, a brief plateau occurs, indicating that the loss is of CH3OH from complex 1. As the temperature continues to rise, the organic structure of the complex collapses, the overall framework collapses, and the final product accounts for 72.5%.
[0053] Example 8: Magnetic Property Testing
[0054] The magnetic susceptibility of complex 1 powder sample was measured using a 1000 Oe DC field within a temperature range of 0-300 K. The experimental data showed that the magnetic susceptibility of complex 1 was 32.51 cm⁻¹. 3 K mol -1 Nearly 3 Dy III and 2 Ni II Theoretical value of ions in uncoupled state ( Figure 6 Analysis of the fitted curves shows that as the temperature decreases, the χ² of this complex... M The T value gradually decreases, possibly due to the decay of the sublevel of the Stark excited state and the Ni II There are antiferromagnetic interactions between the ions. The χ² of this compound at 2 K... M T reached 26.80 cm 3 The lowest value of K·mol⁻¹ was measured. The magnetization of complex 1 in the magnetic field range of 0-8 T and at different temperatures was measured. Figure 7 The results showed that the magnetization curve of the complex had a maximum value of 17.03 Nµ at 2 K and 7 T. B This value is lower than the theoretical saturation value for five independent metal ions, a phenomenon likely caused by Stark level splitting and magnetic anisotropy. For example... Figure 8 As shown, the magnetic susceptibility curves of complex 1 do not overlap, indicating the existence of a low-potential excited state in this system. AC magnetic susceptibility tests were conducted on complex 1 under zero external magnetic field and under an applied external magnetic field of 1000 Oe within the temperature range of 2-20 K. The test results show that the quantum tunneling effect in complex 1 is strong, and the AC magnetic susceptibility does not exhibit a temperature- and frequency-dependent imaginary part signal. Figure 9 and Figure 10In summary, coordination compound 1 exhibits significant magnetic anisotropy, Stark level splitting, and a strong quantum tunneling effect, making it an ideal model coordination compound for exploring magnetic interactions, magnetic relaxation mechanisms, and quantum tunneling effects in rare-earth-transition dissimilar metal systems. Furthermore, its multi-metallic central structure provides a reference for developing novel molecular-based magnetic materials.
[0055] While some embodiments of the present general inventive concept have been shown and described, those skilled in the art will understand 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 by the claims and their equivalents.
Claims
1. A pentanuclear rare earth-transition heterometallic complex, characterized in that, The pentanuclear rare earth-transition heterometallic complex has a bow-shaped metallic framework structure, belongs to the tetragonal crystal system, and has the molecular formula Dy3Ni2(L)3(HL)2(N3)4(H2O)2(CF3SO3)·2CH3OH·5H2O, where HL = partially deprotonated 1,2-di(1-methyl-1H-benzo[d]imidazol-2-yl)ethane-1,2-diol, L = fully deprotonated 1,2-di(1-methyl-1H-benzo[d]imidazol-2-yl)ethane-1,2-diol), space group P43212, and cell parameters: a = 25.8160(9) Å, b = 25.8160(9) Å, c = 47.3557(15) Å, α = 90°, β = 90°, γ = 90°, V = 31561(2) Å 3 .
2. A method for preparing the pentanuclear rare earth-transition heterometallic complex as described in claim 1, characterized in that, The preparation method is as follows: Dy(CF3SO3)3, NiCl2·6H2O and ligand H2L are mixed and dissolved in a mixed solvent of CH3OH and H2O. The mixture is stirred at room temperature until homogeneous. Et3N and NaN3 are added, and the mixture is heated and allowed to stand to volatilize, resulting in blue blocky crystals. The blue blocky crystals are pentanuclear rare earth-transition heterometallic complexes. H2L is 1,2-di(1-methyl-1H-benzo[d]imidazol-2-yl)ethane-1,2-diol.
3. The preparation method according to claim 2, characterized in that, The molar ratio of organic ligands H2L, Dy(CF3SO3)3, NiCl2·6H2O, NaN3, and Et3N is 2:1:1:2:
6.
4. The preparation method according to claim 2, characterized in that, In the mixed solvent, the volume ratio of CH3OH to H2O is 1:
1.
5. The preparation method according to claim 2, characterized in that, Stirring at room temperature for 5-10 minutes.
6. The preparation method according to claim 2, characterized in that, The volume of mixed solvent used is 4-8 mL for every 0.1 mmol of organic ligand H2L.
7. The preparation method according to claim 2, characterized in that, The heating reaction is carried out at a temperature of 70-90℃ for 8-12 hours.
8. The preparation method according to claim 2, characterized in that, The settling and evaporation time is 12-16 days.
9. The application of the pentanuclear rare earth-transition heterometallic complex as described in claim 1 in the preparation of molecular magnetic materials.
10. The application of the pentanuclear rare earth-transition heterometallic complex as described in claim 1 in the preparation of molecular memory materials.