A series of crystalline MOFs based on 9-linked trinuclear lanthanide metal clusters, their preparation methods and applications
By preparing and controlling a unique 9-linked trinuclear lanthanide cluster-based MOF material, the problem of controlling the SHG performance of MOF materials in the field of second harmonic generation was solved. The gradient adjustment of SHG performance and the clear link between structural performance were realized. The material has high porosity and good nonlinear optical properties.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- NANKAI UNIV
- Filing Date
- 2023-11-09
- Publication Date
- 2026-07-17
Smart Images
Figure CN117362676B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of MOF material preparation technology, specifically to a series of preparation methods for trinuclear lanthanide metal cluster-based metal-organic framework materials and their applications in second harmonic generation. Background Technology
[0002] Developing novel application-oriented functional materials through structural design and synthesis is a highly challenging problem. The key scientific issue is understanding and deeply analyzing the relationship between structure and performance, thereby designing and synthesizing novel high-performance materials that meet specific needs. The rational design of building blocks with specific dimensions, geometries, and symmetries, and their self-assembly through strong coordination bonds, to construct application-oriented high-performance metal-organic frameworks (MOFs), is of significant research importance and potential application value, capable of meeting practical application requirements.
[0003] Metal-organic frameworks (MOFs) are a class of tunable and scalable crystalline framework materials. They allow for the design and control of solid-state material properties, such as second harmonic generation (SHG), through the pre-designed framework and building blocks. SHG is one of the most important nonlinear optical phenomena, with broad research and application value in laser manufacturing, optical communication, live-cell imaging, and military applications. The factors influencing SHG signals are complex, and non-centrosymmetric arrangement plays a crucial role in SHGs. However, the following challenges exist in this field: firstly, the SHG performance of synthesized MOFs is generally poor; secondly, SHG performance is difficult to control; and finally, the relationship between the structure and performance of MOFs exhibiting high-performance SHGs remains unclear. Therefore, successfully synthesizing a series of MOFs with tunable SHG performance is a challenging scientific problem. Summary of the Invention
[0004] The purpose of this invention is to address the challenges of controlling the performance of SHGs and the ambiguous relationship between structure and performance. It provides a series of methods for preparing trinuclear lanthanide cluster-based MOFs with unique 9-connections and their application in second harmonic generation. This series of nonlinear optical crystalline materials not only allows for the control of SHG performance by adjusting the number of electrons in lanthanide ions, but also, through theoretical calculations and in-depth analysis of crystal structures, reveals that the chiral driving force of the 9-connected trinuclear lanthanide metal clusters is the source of SHG activity. This invention not only introduces a series of novel nonlinear optical crystalline materials with tunable SHG performance but also clarifies the relationship between trinuclear lanthanide cluster-based MOFs with unique 9-connections and second harmonic generation performance. It provides valuable experience, new design strategies, and theoretical guidance for the structural design and synthesis of application-oriented novel MOF materials.
[0005] The technical solution of the present invention:
[0006] A series of trinuclear lanthanide cluster-based MOFs materials with SHG properties based on unique 9-connections are described. These materials are nonlinear optical crystalline materials of trinuclear cluster-based lanthanide metal-organic frameworks, possessing a gfy topological network structure, with the general structural formula [Ln3(m3-O)(C]. 15 The material, named NKU-405-Ln (Ln = Eu / Tb / Gd), consists of a trinuclear lanthanide cluster connected to nine ligands via coordinate bonds. Three lanthanide atoms are bridged by an oxygen atom, forming a triangular distribution. Three ligands are above the equatorial plane, three below, and three more on the equatorial plane. Three terminal water atoms on the equatorial plane act as hydrogen bond donors, exposing numerous directional channels. The three thiophene S atoms in the ligands exhibit polarity, and the S-containing heterocycles break the mirror symmetry of the ligands. NKU-405-Ln possesses hexagonal channels containing three dimethylamine cations (C2H8N)2 to balance the charge of the framework material. +
[0007] A method for preparing a 9-linked trinuclear lanthanide metal cluster-based MOF material with second harmonic generation properties includes the following steps:
[0008] (1) The organic ligand benzo[1,2-b:3,4-b':5,6-b']trithiophene-2,5,8-tricarboxylic acid (H3BTTC), metal salt, concentrated nitric acid, template agent o-fluorobenzoic acid, and solvent are mixed in a certain proportion and subjected to a hydrothermal reaction. After synthesis, the mixture is filtered, washed, and dried to obtain the preliminary structure with the general formula [Ln3(m3-O)(C 15The trinuclear cluster-based lanthanide metal-organic framework NKU-405-Ln is a nonlinear optical crystalline material; the molar ratio of the organic ligand to the metal salt is 1:(1-5); preferably, the molar ratio of the organic ligand to the metal salt is 1:(1-2).
[0009] (2) The initially obtained crystal material was washed with DMF solution, and the trinuclear lanthanide cluster-based MOF nonlinear optical crystal material with unique 9-linkage was named NKU-405-Ln (Ln=Eu / Tb / Gd).
[0010] Furthermore, the metal salt is a lanthanide metal nitrate, specifically europium nitrate hexahydrate, terbium nitrate hexahydrate, gadolinium nitrate hexahydrate, europium chloride hexahydrate, terbium chloride hexahydrate, and gadolinium chloride hexahydrate;
[0011] Furthermore, the solvent is N,N-dimethylformamide (DMF) and water.
[0012] Furthermore, the temperature of the hydrothermal reaction is 100–115°C; the reaction time is 48–72 h, preferably the reaction temperature is 105–110°C, and preferably the reaction time is 96 h.
[0013] The NKU-405-Ln material provided by this invention can be applied to the performance intensity tuning of second harmonic generation (SHG). Under 940 nm excitation, the SHG performance can be graded from below that of Y-type quartz to comparable to Y-type quartz, and then to several times the strength of Y-type quartz, through in-situ substitution of lanthanide metal ions. NKU-405-Ln not only achieves SHG performance tuning, but theoretical calculations and crystal structure analysis also show that the unique 9-linked trinuclear lanthanide metal cluster is the key to achieving SHG performance, clearly elucidating the relationship between structure and performance.
[0014] The advantages and beneficial effects of this invention are:
[0015] (1) The preparation process of this series of 9-linked trinuclear lanthanide metal cluster-based MOFs is simple and the structure is stable.
[0016] (2) The 9-connected trinuclear lanthanide metal cluster-based MOFs material has a large porosity and pore size.
[0017] (3) The 9-connected trinuclear lanthanide metal cluster-based MOFs material has the advantage of adjustable second harmonic generation performance and good second-order nonlinear optical properties. Attached Figure Description
[0018] Figure 1The diagram shows the crystal structure of the material in Example 1. (a) is a diagram of the secondary building blocks, including a trinuclear lanthanide metal cluster as an unstructured building block. (b) is a diagram of a three-connected benzo[1,2-b:3,4-b':5,6-b']trithiophene-2,5,8-tricarboxylic acid (H3BTTC) as an organized building block. (c) is a diagram of the three-dimensional network structure and topology of NKU-405-Ln.
[0019] Figure 2 This is a crystal pore diagram of the material in Example 1.
[0020] Figure 3 The X-ray diffraction patterns of NKU-405-Eu in different solvents in Example 1 are shown.
[0021] Figure 4 The X-ray diffraction patterns of NKU-405-Tb in different solvents in Example 1 are shown.
[0022] Figure 5 The X-ray diffraction patterns of NKU-405-Gd in different solvents in Example 1 are shown.
[0023] Figure 6 The thermogravimetric analysis diagram of NKU-405-Ln in Example 1 is shown.
[0024] Figure 7 This is a field emission scanning electron microscope image of the NKU-405-Eu in Example 1.
[0025] Figure 8 This is a field emission scanning electron microscope image of NKU-405-Tb in Example 1.
[0026] Figure 9 This is a field emission scanning electron microscope image of NKU-405-Gd in Example 1.
[0027] Figure 10 The NKU-405-Ln in Example 1 is a self-made combined polarization optical device that uses a femtosecond pulsed laser as a pump.
[0028] Figure 11 The nonlinear optical spectra of NKU-405-Eu under different pump light excitations in Example 1 are shown.
[0029] Figure 12 The nonlinear optical spectra of NKU-405-Tb under different pump light excitations in Example 1 are shown.
[0030] Figure 13 The nonlinear optical spectra of NKU-405-Gd under different pump light excitations in Example 1 are shown.
[0031] Figure 14 The polarization dependence of the intensity of the second harmonic generation of NKU-405-Ln in vertical orientation in Example 1.
[0032] Figure 15 The energy dependence of the second harmonic generation intensity of NKU-405-Ln in Example 1.
[0033] Figure 16 This is a comparison of the second harmonic generation intensity of NKU-405-Ln crystal and Y-type quartz in Example 1.
[0034] Figure 17 This is a schematic diagram of the electronic structure of NKU-405-Ln in Example 1. (a), (b), and (c) are the band diagrams of NKU-405-Gd, NKU-405-Eu, and NKU-405-Tb, respectively; (d), (e), and (f) are the density of states diagrams of NKU-405-Gd, NKU-405-Eu, and NKU-405-Tb, respectively. Detailed Implementation
[0035] To make the objectives, technical solutions, and advantages of this invention clearer, the content of this invention will be further explained below in conjunction with the accompanying drawings and embodiments. However, these examples do not limit the scope of protection of this invention. Based on the technical solutions of this invention, various modifications or variations that can be made by those skilled in the art without creative effort are still within the scope of protection of this invention.
[0036] Example 1
[0037] Synthesis of NKU-405-Ln material
[0038] 5 mg of organic ligand H3BTTC, 15 mg of europium nitrate hexahydrate or terbium nitrate hexahydrate or gadolinium nitrate hexahydrate, and 50 mg of o-fluorobenzoic acid were dissolved in 2 mL of DMF and 0.5 mL of water. The mixture was sonicated for 15 min and reacted at 105 °C for 48 h. After the reaction was completed, the mixture was slowly cooled to room temperature in air. The mixture was then filtered and washed three times with DMF. After drying, a relatively pure 9-linked trinuclear lanthanide metal cluster-based MOF material was obtained, named NKU-405-Ln. A schematic diagram of its microstructure is shown below. Figure 1 and Figure 2 .
[0039] To test the solvent stability of NKU-405-Ln, the freshly synthesized sample was immersed in a common organic solvent for 48 hours before the PXRD data of the sample was measured. Figures 3 to 5 As shown in the figure, this series of materials still maintains good structural integrity, indicating that it has good solvent stability.
[0040] To test the thermal stability of NKU-405-Ln, the freshly synthesized sample was washed, dried, and then subjected to thermogravimetric analysis. Figure 6 As shown in the figure, this series of materials decomposes at approximately 450℃, exhibiting good thermal stability.
[0041] To test the morphology of NKU-405-Ln, field emission scanning electron microscopy was performed. The results are shown in [Figure number missing]. Figures 7 to 9 It has the shape of a hexagonal prism.
[0042] To test the nonlinear optical properties of NKU-405-Ln, the material was subjected to... Figure 10 The test was conducted under the schematic diagram of the device.
[0043] From the appendix Figure 10 As can be seen, the anisotropic nonlinear optical property measurement device of the present invention includes, in sequence, a pulsed laser generator, a polarizer for adjusting the polarization direction of the linearly polarized light emitted by the pulsed laser generator, an attenuator 1 for adjusting the power of the linearly polarized light emitted by the pulsed laser generator, a filter 1 for filtering the wavelength of the linearly polarized light emitted by the pulsed laser generator, an attenuator 2 for adjusting the power of a single beam of linearly polarized light, a prism 1 for focusing the linearly polarized light on the optical path, an electric sample stage for driving the sample, a prism 2 confocal with the prism 1, a filter 2 for filtering the background light of the reflected linearly polarized light, a polarizer for adjusting the polarization direction of the reflected linearly polarized light, a prism 3 for focusing the linearly polarized light into the detector, and a photon detector. The pulsed laser generator of the present invention can select picosecond lasers, nanosecond lasers, and femtosecond lasers as the Z-scan light source. The electric sample stage can move precisely along the optical path direction, i.e., along the Z-axis, precisely from Z to +Z. The optical signal carrying polarized light information is captured by the detector's OL and charge-coupled device (CCD) and used to perform optical performance analysis on the NKU-405-Ln sample on the sample stage.
[0044] To further analyze the nonlinear optical properties of NKU-405-Ln, including the wavelength dependence of the second harmonic generation performance of this series of materials ( Figures 11 to 13 NKU-405-Ln exhibits second harmonic generation effects at different excitation wavelengths ranging from 800 to 1040 nm. The optimal excitation wavelength for NKU-405-Eu is 1020 nm, for NKU-405-Tb it is 980 nm, and for NKU-405-Gd it is 940 nm. Polarization dependence ( Figure 14 This indicates that NKU-405-Ln all exhibit polarity, with the order of polarity from strongest to weakest being NKU-405-Gd > NKU-405-Eu > NKU-405-Tb; energy dependence ( Figure 15This indicates that NKU-405-Ln exhibits good second-order nonlinear effects and a high optical damage threshold; a comparison of its second harmonic generation intensity with that of Y-type quartz under the same test conditions ( Figure 16 (To be tested)
[0045] To analyze the electronic structure characteristics of NKU-405-Ln, the calculated band diagram and energy density of this series of materials are as follows: Figure 17 As shown, the band gaps of NKU-405-Gd, NKU-405-Eu, and NKU-405-Tb are 2.95, 2.62, and 2.70 eV, respectively. Analysis of the density of states diagrams reveals that the electron transfer process involves charge transfer from the metal cluster to the ligand and charge transfer within the ligand.
[0046] Finally, the polarity of the NKU-405-Ln crystal structure was calculated, as shown in Table 1.
[0047] Table 1. Octuple moment calculation results of NKU-405-Ln (excluding dimethylamine cations)
[0048]
[0049] This is consistent with the experimental results of the present invention, and the order of magnitude of the octet moments is NKU-405-Gd>NKU-405-Eu>NKU-405-Tb.
[0050] Example 1:
[0051] Synthesis of NKU-405-Ln material
[0052] 5 mg of organic ligand H3BTTC, 15 mg of europium nitrate hexahydrate or terbium nitrate hexahydrate or gadolinium nitrate hexahydrate, and 50 mg of o-fluorobenzoic acid were dissolved in 2 mL of LDM and 0.5 mL of water, sonicated for 15 min, and reacted at 100 °C for 48 h.
[0053] Example 2:
[0054] Synthesis of NKU-405-Ln material
[0055] 5 mg of organic ligand H3BTTC, 15 mg of europium chloride hexahydrate or terbium chloride hexahydrate or gadolinium chloride hexahydrate, and 50 mg of o-fluorobenzoic acid were dissolved in 2 mL of LDMF and 0.5 mL of water, sonicated for 15 min, and reacted at 100 °C for 48 h.
[0056] Example 3:
[0057] Synthesis of NKU-405-Ln material
[0058] Dissolve 5 mg of organic ligand H3BTTC, 15 mg of europium nitrate hexahydrate or terbium nitrate hexahydrate or gadolinium nitrate hexahydrate, and 50 mg of o-fluorobenzoic acid in 2 mL of DMF and 0.5 mL of water, then add 0.01 mL of 3.5 M concentrated nitric acid in DMF solution, sonicate for 15 min, and react at 100 °C for 48 h.
[0059] Example 4:
[0060] Synthesis of NKU-405-Ln material
[0061] 5 mg of organic ligand H3BTTC, 15 m of europium chloride hexahydrate or terbium chloride hexahydrate or gadolinium chloride hexahydrate, and 50 mg of o-fluorobenzoic acid were dissolved in 2 m LDM and 0.5 mL of water. Then, 0.01 mL of DMF solution of 3.5 M concentrated nitric acid was added, and the mixture was sonicated for 15 min and reacted at 100 °C for 48 h.
[0062] Example 5:
[0063] Synthesis of NKU-405-Ln material
[0064] 5 mg of organic ligand H3BTTC, 15 mg of europium nitrate hexahydrate or terbium nitrate hexahydrate or gadolinium nitrate hexahydrate, and 50 mg of o-fluorobenzoic acid were dissolved in 2 mL of LDM and 0.5 mL of water, sonicated for 15 min, and reacted at 105 °C for 48 h.
[0065] Example 6:
[0066] Synthesis of NKU-405-Ln material
[0067] 5 mg of organic ligand H3BTTC, 15 mg of europium chloride hexahydrate or terbium chloride hexahydrate or gadolinium chloride hexahydrate, and 50 mg of o-fluorobenzoic acid were dissolved in 2 mL of LDMF and 0.5 mL of water, sonicated for 15 min, and reacted at 105 °C for 48 h.
[0068] Example 7:
[0069] Synthesis of NKU-405-Ln material
[0070] Dissolve 5 mg of organic ligand H3BTTC, 15 mg of europium nitrate hexahydrate or terbium nitrate hexahydrate or gadolinium nitrate hexahydrate, and 50 mg of o-fluorobenzoic acid in 2 mL of DMF and 0.5 mL of water, then add 0.01 mL of 3.5 M concentrated nitric acid in DMF solution, sonicate for 15 min, and react at 105 °C for 48 h.
[0071] Example 8:
[0072] Synthesis of NKU-405-Ln material
[0073] 5 mg of organic ligand H3BTTC, 15 m of europium chloride hexahydrate or terbium chloride hexahydrate or gadolinium chloride hexahydrate, and 50 mg of o-fluorobenzoic acid were dissolved in 2 m LDM and 0.5 mL of water. Then, 0.01 mL of DMF solution of 3.5 M concentrated nitric acid was added, and the mixture was sonicated for 15 min and reacted at 105 °C for 48 h.
[0074] Example 9:
[0075] Synthesis of NKU-405-Ln material
[0076] 5 mg of organic ligand H3BTTC, 15 mg of europium nitrate hexahydrate or terbium nitrate hexahydrate or gadolinium nitrate hexahydrate, and 50 mg of o-fluorobenzoic acid were dissolved in 2 mL of LDM and 0.5 mL of water, sonicated for 15 min, and reacted at 110 °C for 48 h.
[0077] Example 10:
[0078] Synthesis of NKU-405-Ln material
[0079] 5 mg of organic ligand H3BTTC, 15 mg of europium chloride hexahydrate or terbium chloride hexahydrate or gadolinium chloride hexahydrate, and 50 mg of o-fluorobenzoic acid were dissolved in 2 mL of LDMF and 0.5 mL of water, sonicated for 15 min, and reacted at 110 °C for 48 h.
[0080] Example 11:
[0081] Synthesis of NKU-405-Ln material
[0082] 5 mg of organic ligand H3BTTC, 15 mg of europium nitrate hexahydrate or terbium nitrate hexahydrate or gadolinium nitrate hexahydrate, and 50 mg of o-fluorobenzoic acid were dissolved in 2 mL of DMF and 0.5 mL of water. Then, 0.01 mL of 3.5 M concentrated nitric acid DMF solution was added, and the mixture was sonicated for 15 min and reacted at 110 °C for 48 h.
[0083] Example 12:
[0084] Synthesis of NKU-405-Ln material
[0085] 5 mg of organic ligand H3BTTC, 15 m of europium chloride hexahydrate or terbium chloride hexahydrate or gadolinium chloride hexahydrate, and 50 mg of o-fluorobenzoic acid were dissolved in 2 m LDM and 0.5 mL of water. Then, 0.01 mL of DMF solution of 3.5 M concentrated nitric acid was added, and the mixture was sonicated for 15 min and reacted at 110 °C for 48 h.
[0086] Example 13:
[0087] Synthesis of NKU-405-Ln material
[0088] 5 mg of organic ligand H3BTTC, 15 mg of europium nitrate hexahydrate or terbium nitrate hexahydrate or gadolinium nitrate hexahydrate, and 50 mg of o-fluorobenzoic acid were dissolved in 2 mL of LDM and 0.5 mL of water, sonicated for 15 min, and reacted at 115 °C for 48 h.
[0089] Example 14:
[0090] Synthesis of NKU-405-Ln material
[0091] 5 mg of organic ligand H3BTTC, 15 mg of europium chloride hexahydrate or terbium chloride hexahydrate or gadolinium chloride hexahydrate, and 50 mg of o-fluorobenzoic acid were dissolved in 2 mL of LDMF and 0.5 mL of water, sonicated for 15 min, and reacted at 115 °C for 48 h.
[0092] Example 15:
[0093] Synthesis of NKU-405-Ln material
[0094] 5 mg of organic ligand H3BTTC, 15 mg of europium nitrate hexahydrate or terbium nitrate hexahydrate or gadolinium nitrate hexahydrate, and 50 mg of o-fluorobenzoic acid were dissolved in 2 mL of DMF and 0.5 mL of water. Then, 0.01 mL of DMF solution of 3.5 M concentrated nitric acid was added, and the mixture was sonicated for 15 min and reacted at 115 °C for 48 h.
[0095] Example 16:
[0096] Synthesis of NKU-405-Ln material
[0097] 5 mg of organic ligand H3BTTC, 15 m of europium chloride hexahydrate or terbium chloride hexahydrate or gadolinium chloride hexahydrate, and 50 mg of o-fluorobenzoic acid were dissolved in 2 m LDM and 0.5 mL of water. Then, 0.01 mL of 3.5 M concentrated nitric acid DMF solution was added, and the mixture was sonicated for 15 min and reacted at 115 °C for 48 h.
[0098] It should be further noted that the above embodiments are merely implementation methods of specific technical solutions and conditions of the present invention, used for understanding the technical concept of the present invention, and not for limiting the scope of protection of the present invention. Any obvious adjustments and modifications made based on the specific implementation of the present invention should be within the scope of protection of the present invention.
Claims
1. A series of crystalline MOFs based on 9-linked trinuclear lanthanide metal clusters, wherein the materials are 9-linked trinuclear lanthanide metal cluster-based metal-organic frameworks with one-dimensional hexagonal channels and a general structural formula of [Ln3(m3-O)(C 15 H3O6S3)3(H2O)3](C2H8N)2 has a gfy topology network structure and is named NKU-405-Ln, where Ln=Eu, Tb, Gd.
2. The method for preparing the crystalline MOFs based on a 9-connected trinuclear lanthanide metal cluster as described in claim 1, characterized in that, Includes the following steps: The organic ligand benzo[1,2-b:3,4-b':5,6-b']trithiophene-2,5,8-tricarboxylic acid (H3BTTC), metal salt, concentrated nitric acid, template agent o-fluorobenzoic acid, and solvent were mixed in a certain proportion and subjected to a hydrothermal reaction. After synthesis, the mixture was filtered, washed, and dried to obtain the preliminary structure with the general formula [Ln3(m3-O)(C 15 A trinuclear cluster-based lanthanide metal-organic framework material, H3O6S3)3(H2O)3](C2H8N)2; wherein the molar ratio of the organic ligand to the metal salt is 1:(1~2); The solvent is N,N-dimethylformamide (DMF) and water.
3. The preparation method according to claim 2, characterized in that, The metal salt is a lanthanide metal salt, namely europium nitrate hexahydrate, terbium nitrate hexahydrate, gadolinium nitrate hexahydrate, europium chloride hexahydrate, terbium chloride hexahydrate, and gadolinium chloride hexahydrate.
4. The preparation method according to claim 2, characterized in that, The hydrothermal reaction temperature is 100℃~115℃; the reaction time is 48–96h.
5. The preparation method according to claim 2, characterized in that, The concentrated nitric acid has a concentration of 3.5 mol / L and a dosage of 0-150 μL.
6. The preparation method according to claim 2, characterized in that, The amount of the organic ligand H3BTTC is 5 mg, the amount of the template agent o-fluorobenzoic acid is 50-100 mg, the amount of DMF in the solvent is 2 mL, and the amount of water is 0.5 mL.
7. The preparation method according to claim 4, characterized in that, The hydrothermal reaction temperature is 105℃-110℃, and the reaction time is 48h.
8. The application of the MOF crystalline material based on a 9-connected trinuclear lanthanide metal cluster as described in claim 1 in the generation of second harmonics.
9. The application according to claim 8, characterized in that, The application is that, under 940nm excitation, the intensity order of the second harmonic generation is NKU-405-Gd>NKU-405-Eu>NKU-405-Tb.