MOF (Metal Organic Framework) material based on metal manganese-oxygen chain unit as well as preparation method and application of MOF material

Abstract

The invention discloses a metal manganese-oxygen chain unit-based MOF (Metal Organic Framework) material and a preparation method and application thereof, the chemical formula of the metal manganese-oxygen chain unit-based MOF material is [Mn3 (TCA) 2 (H2O) 2], and H3TCA is an organic ligand 4, 4 '4' '-triformic acid triphenylamine. According to the MOF material, a metal manganese-oxygen chain unit and an organic ligand H3TCA form a three-dimensional porous structure with rhombic pore channels. The MOF material of the metal manganese-oxygen chain unit has high thermal stability and good temperature sensing performance.

Description

Technical Field

[0001] The present invention belongs to the technical fields of the preparation of crystalline porous materials and temperature sensing, and particularly relates to a MOF material based on metal manganese-oxygen chain units, a preparation method thereof, and an application thereof. Background Art

[0002] Temperature is an important parameter in the fields of natural science, industrial production, and human daily life. The accurate measurement of temperature has important significance and research value for scientific research and production practice. Currently, there are various types of thermometers. However, in some special cases, such as for temperature measurement in low-temperature environments, high-temperature environments, microscopic systems, strongly corrosive environments, or strong electromagnetic conditions, traditional mercury thermometers and thermocouple thermometers often fail to meet the requirements. Therefore, it is of extremely important significance to seek new temperature detection methods with high sensitivity and high precision.

[0003] As a new type of temperature detection technology, fluorescence temperature measurement has attracted extensive attention due to its advantages such as high sensitivity, fast response speed, strong anti-interference ability, and non-contact measurement. Currently, fluorescent MOF materials (Metal–organic framework, MOF) have unique framework structures and luminescence performance advantages, especially characteristics such as rich luminescence sites, wide emission wavelength ranges, adjustable structures, and easy functionalization, and can be widely applied in multiple fields such as medical health monitoring, environmental monitoring, and industrial automation. Utilizing the relationship between the fluorescence intensity ratio of the luminescence centers in the MOF structure and temperature changes to achieve temperature detection provides broad development space and prospects for the design and development of intelligent fluorescent temperature sensing materials. More importantly, there is an urgent need for systematic research and development on the construction of highly stable and high-performance temperature sensor MOFs materials based on polycarboxylic acid ligands with large π delocalized systems. Summary of the Invention

[0004] The first object of the present invention is to provide a MOF material based on metal manganese-oxygen chain units. The chemical formula of the MOF material of the metal manganese-oxygen chain units is [Mn3(TCA)2(H2O)2], named Mn-MOF1. The Mn-MOF1 material forms a three-dimensional porous structure with rhombic pores through the metal manganese-oxygen chain units and the organic ligand H3TCA. H3TCA is 4,4'4''-tricarboxyaniline, and the structural formula is as follows: .

[0005] Furthermore, the crystal structure of the Mn-MOF1 belongs to the monoclinic system, and the space group is C 2 / c , and the unit cell parameters are: a = 27.302(4) Å, b = 9.1313(13), c = 26.814(4),α = 90.00 o , β = 120.495(5) o , γ =90.00 o 。

[0006] Furthermore, in the structure of Mn-MOF1, the asymmetric unit includes 1.5 crystallographically independent Mn 2+ , 1 deprotonated H3TCA ligand, and 1 coordinated water molecule; Among them, Mn 2+ adopts a 6-coordinate octahedral coordination configuration, but has two coordination modes, Mn1 and Mn2. Mn1 coordinates with 6 carboxylate oxygen atoms from 6 different deprotonated TCA 3- ligands, and Mn2 coordinates with 5 carboxylate oxygen atoms from 4 different deprotonated TCA 3- ligands and 1 oxygen atom of a water molecule.

[0007] Furthermore, in the structure of Mn-MOF1, Mn1 and Mn2 are connected by two carboxylate monodentate bridges and one carboxylate chelate-monodentate linkage, while Mn2 and Mn2 are connected by sharing two carboxylate oxygens to form a one-dimensional metal manganese-oxygen chain unit.

[0008] Meanwhile, the deprotonated H3TCA ligand adopts μ 7- η 1 : η 1 : η 1 : η 2 : η 1 : η 2 to connect metal ions; along the b axis direction, the three-dimensional structure of Mn-MOF1 has rhombic pores with a size of about 10 × 10 Å 2 .

[0009] Furthermore, the thermal stability of the Mn-MOF1 material reaches 430 o °C.

[0010] The present invention also provides a preparation method of the MOF material based on the metal manganese-oxygen chain unit, including the following steps: Adding manganese chloride tetrahydrate MnCl2·4H2O and the organic ligand H3TCA into a mixed solution of N,N-dimethylformamide DMF and acetonitrile CH3CN, and obtaining the Mn-MOF1 material after solvothermal reaction.

[0011] Furthermore, in the mixed solution, the concentration of manganese chloride tetrahydrate is 0.02 - 0.04 mol / L, and the concentration of the organic ligand H3TCA is 0.0053 - 0.0106 mol / L; the addition ratio of MnCl2·4H2O to DMF is (0.1 - 0.2) mmol: 3 mL, and the volume ratio of DMF to CH3CN in the mixed solution is (1.5 - 2):1.

[0012] Furthermore, the temperature of the solvothermal reaction is 120 - 125 °C, and the reaction time is 1 - 2 days.

[0013] Furthermore, after the prepared Mn-MOF1 material is washed 3 - 5 times with DMF and CH3CN respectively, it is dried at room temperature for standby.

[0014] The present invention also provides the application of the MOF material based on the metal manganese-oxygen chain unit as a temperature sensor in the field of temperature sensing.

[0015] Advantages of the present invention: The MOF material of the metal manganese-oxygen chain unit of the present invention has a novel structure. Observed along the b axis direction, rhombic pores with a size of about 10 × 10 Å are formed by the metal manganese-oxygen chain unit and the organic ligand H3TCA in the three-dimensional structure. 2 . The thermal stability of the Mn-MOF1 material of the present invention reaches 430 o °C. The Mn-MOF1 of the present invention has good application prospects as a fluorescence temperature sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is the asymmetric unit diagram of Mn-MOF1.

[0017] Figure 2 It is the metal manganese-oxygen chain unit diagram of Mn-MOF1.

[0018] Figure 3 It is the connection mode diagram of the organic ligand H3TCA of Mn-MOF1.

[0019] Figure 4 It is the three-dimensional structure diagram of Mn-MOF1.

[0020] Figure 5 It is the SEM morphology diagram of Mn-MOF1.

[0021] Figure 6 It is the X-ray powder diffraction diagram of Mn-MOF1.

[0022] Figure 7 It is the thermogravimetric curve diagram of Mn-MOF1.

[0023] Figure 8 It is the fluorescence emission spectrum diagram of Mn-MOF1 and the organic ligand H3TCA.

[0024] Figure 9 It is the fluorescence emission spectrum diagram of Mn-MOF1 at different temperatures.

[0025] Figure 10 It is the linear fitting diagram of the fluorescence emission intensity of Mn-MOF1 and temperature. Specific implementation mode

[0026] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments, but the protection scope of the present invention is not limited to these embodiments.

[0027] Example 1 The preparation method of the MOF material of the metal manganese-oxygen chain unit in this example is as follows: Add MnCl2·4H2O (0.15 mmol) and the organic ligand H3TCA (0.0265 mmol) into the mixed solution system of DMF (3 mL) and CH3CN (2 mL). The thermal reaction is placed in a constant temperature drying oven and heated at a constant temperature of 125 °C for 1 day, and then naturally cooled to room temperature. A large number of yellow blocky crystals can be obtained. Filter and dry at room temperature to obtain the prepared Mn-MOF1 material. The yield is 0.019 g and the yield rate is 63.1%.

[0028] Example 2 The preparation method of the MOF material of the metal manganese-oxygen chain unit in this example is as follows: Add MnCl2·4H2O (0.125 mmol) and the organic ligand H3TCA (0.0265 mmol) into the mixed solution system of DMF (3 mL) and CH3CN (2 mL). The thermal reaction is placed in a constant temperature drying oven and heated at a constant temperature of 120 °C for 2 days, and then naturally cooled to room temperature. A large number of yellow blocky crystals can be obtained. Filter and dry at room temperature to obtain the prepared Mn-MOF1 material. The yield is 0.015 g and the yield rate is 49.8%.

[0029] Example 3 The preparation method of the MOF material of the metal manganese-oxygen chain unit in this example is as follows: Add MnCl2·4H2O (0.2 mmol) and the organic ligand H3TCA (0.0398 mmol) into the mixed solution system of DMF (3 mL) and CH3CN (2 mL). The thermal reaction is placed in a constant temperature drying oven and heated at a constant temperature of 125 °C for 1 day, and then naturally cooled to room temperature. A large number of yellow blocky crystals can be obtained. Filter and dry at room temperature to obtain the prepared Mn-MOF1 material. The yield is 0.022 g and the yield rate is 73.1%.

[0030] Example 4 The preparation method of the MOF material of the manganese-oxygen chain unit in this example is as follows: Add MnCl2·4H2O (0.25 mmol) and the organic ligand H3TCA (0.0795 mmol) into the mixed solution system of DMF (5 mL) and CH3CN (2.5 mL). The thermal reaction is placed in a constant-temperature drying oven and heated at a constant temperature of 125 °C for 1 day, and then naturally cooled to room temperature. A large number of yellow block crystals can be obtained. Filter and dry at room temperature to obtain the prepared Mn-MOF1 material. The yield is 0.050 g, and the yield rate is 55.3%.

[0031] Example 5 The preparation method of the MOF material of the manganese-oxygen chain unit in this example is as follows: Add MnCl2·4H2O (0.1 mmol) and the organic ligand H3TCA (0.0265 mmol) into the mixed solution system of DMF (3 mL) and CH3CN (2 mL). The thermal reaction is placed in a constant-temperature drying oven and heated at a constant temperature of 125 °C for 1 day, and then naturally cooled to room temperature. A large number of yellow block crystals can be obtained. Filter and dry at room temperature to obtain the prepared Mn-MOF1 material. The yield is 0.01 g, and the yield rate is 33.3%.

[0032] (1) Crystal data of the Mn-MOF1 material At 296(2) K, crystal data was collected using a Bruker D8 Quest CMOS single-crystal diffractometer. The data collection used Mo-Kα (λ = 0.71073 Å) target rays monochromatized by a graphite monochromator. Data processing and reduction were performed using the SAINT program. Structure analysis and refinement were performed using the SHELXL-97 program. The structure diagram is shown in the appendix Figures 1-4 . The crystallographic data is shown in Table 1

[0033] Table 1 Crystallographic data of this metal-organic framework material

[0034] Appendix Figure 1 The structure diagram in the appendix shows that in the Mn-MOF1 material, the asymmetric unit includes 1.5 crystallographically independent Mn 2+ , 1 TCA 3-Ligand, one coordinated water molecule. Symmetry operation codes in the figure: a = 1 - x, 1 - y, 1 - z; b = 1 / 2 + x, 3 / 2 - y, 1 / 2 + z; c = 1 / 2 - x, -1 / 2 + y, 1 / 2 - z; d = 1 / 2 - x, 1 / 2 + y, 1 / 2 - z; e = x, 1 - y, 1 / 2 + z; f = 1 - x, y, 1 / 2 - z.).

[0035] Appendix Figure 2 The structure diagram of... shows that in the Mn-MOF1 material, the metal Mn has two coordination modes. Mn1 coordinates with 6 carboxyl oxygen atoms from 6 different TCA 3- ligands, while Mn2 coordinates with 5 carboxyl oxygen atoms from 4 different TCA 3- ligands and the oxygen atom of 1 water molecule. In Mn-MOF, Mn1 and Mn2 are connected by two carboxylate monodentate bridges and one carboxylate chelate-monodentate linkage, while Mn2 and Mn2 share two carboxyl oxygen atoms to form a one-dimensional metal manganese-oxygen chain unit.

[0036] Appendix Figure 3 The structure diagram of... shows the way of the organic ligand that has removed the hydrogen atoms on three carboxyl groups to connect with metal manganese in the Mn-MOF1 material.

[0037] Appendix Figure 4 The structure diagram of... shows the three-dimensional structure diagram of the Mn-MOF1 material. When observed along the b axis direction, diamond-shaped pores are formed in the three-dimensional structure of Mn-MOF, with a size of about 10 × 10 Å 2 .

[0038] Appendix Figure 5 The SEM morphology diagram of... shows that the Mn-MOF1 material is in a block shape, with a size of 50 - 200 microns.

[0039] Appendix Figure 6 The X-ray powder diffraction pattern of... shows that the diffraction peak heights of the PXRD spectrum of the Mn-MOF1 material and the simulated PXRD spectrum of the single crystal structure are in good agreement, indicating that the Mn-MOF1 material has a very high purity.

[0040] Appendix Figure 7 The thermogravimetric curve of... shows the thermal stability analysis of the Mn-MOF1 material, indicating that the material can be stable up to 430 °C.

[0041] (2) Solid fluorescence emission spectrum of the Mn-MOF1 material in this example At room temperature, the solid fluorescence of the Mn-MOF1 material and the organic ligand H3TCA was studied (see Appendix Figure 8). The organic ligand H3TCA exhibits an extremely strong fluorescence emission peak at 467 nm, while the Mn-MOF1 material shows an extremely strong fluorescence emission peak at 406 nm. Compared with the fluorescence emission peak of the organic ligand H3TCA, the Mn-MOF1 material has a significant blue shift of approximately 61 nm. This phenomenon can be attributed to the rigidity maintained after the coordination of the carboxyl group of the organic ligand with manganese metal ions in the Mn-MOF1 structure, which increases the energy level between the HOMO and LUMO, resulting in a large blue shift of the Mn-MOF1 material.

[0042] (3) Fluorescence emission spectra of the Mn-MOF1 material in this example at different temperatures Due to the excellent fluorescence properties and good stability of Mn-MOF1, its application in temperature sensing was studied. As Figure 9 shown, the results of the variable-temperature fluorescence spectra of Mn-MOF1 indicate that as the temperature increases (from 80 K to 300 K), the fluorescence intensity gradually decreases and the maximum emission spectrum does not change with temperature, indicating that Mn-MOF1 has very strong stability. In addition, the relationship between the emission intensity and temperature (from 80 K to 300 K) shows a good linear correlation ( R 2 = 0.9758) (see appendix Figure 10 ), indicating that the Mn-MOF1 material has great potential as a luminescent material in the field of low-temperature detection.

[0043] The above shows and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and the descriptions in the specification only illustrate the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A MOF material based on metal manganese-oxygen chain units, characterized in that: The chemical formula is [Mn3(TCA)2(H2O)2], named Mn-MOF1. The Mn-MOF1 material forms a three-dimensional porous structure with rhombus channels through the metal manganese-oxygen chain unit and the organic ligand H3TCA. H3TCA is 4,4'4''-triphenylamine tricarboxylate, and the structural formula is as follows: 。 2. The MOF material based on metal manganese-oxygen chain units according to claim 1, characterized in that: The crystal structure of the Mn-MOF1 belongs to the monoclinic system, and the space group is C 2 / c , the unit cell parameters are: a = 27.302(4) Å, b = 9.1313(13), c = 26.814(4), α = 90.00 o , β = 120.495(5) o , γ = 90.00 o .

3. The MOF material based on metal manganese-oxygen chain units according to claim 1, characterized in that: In the structure of Mn-MOF1, the asymmetric unit consists of 1.5 crystal-independent Mn 2+ , 1 deprotonated H3TCA ligand, 1 coordinated water molecule; Among them, Mn 2+ It adopts a 6-coordinate octahedral coordination configuration, but has two coordination modes Mn1 and Mn2. Mn1 is bound to six different deprotonated TCAs. 3- The six carboxyl oxygen atoms of the ligand are coordinated, and Mn2 is coordinated with four different deprotonated TCAs. 3- The ligand is coordinated by five carboxyl oxygen atoms and one oxygen atom of a water molecule.

4. The MOF material based on metal manganese-oxygen chain units according to claim 1, characterized in that: In the structure of Mn-MOF1, Mn1 and Mn2 are connected by two carboxyl monodentate bridges and one carboxyl chelate-monodentate, while Mn2 and Mn2 are shared by two carboxyl oxygens to form a one-dimensional metal manganese-oxygen chain unit; Deprotonated H3TCA ligand was used μ 7- η 1 : η 1 : η 1 : η 2 : η 1 : η 2 Connect Mn ions; along b In the axial direction, the three-dimensional structure of Mn-MOF1 has diamond-shaped channels with a size of 10 × 10 Å. 2 .

5. The MOF material based on metal manganese-oxygen chain units according to claim 1, characterized in that: The thermal stability of the Mn-MOF1 material reaches 430 o C.

6. A method for preparing a MOF material based on a metal manganese-oxygen chain unit as claimed in any one of claims 1 to 5, characterized in that: The steps include: Manganese chloride tetrahydrate MnCl2·4H2O and organic ligand H3TCA are added to a mixed solution of N,N-dimethylformamide DMF and acetonitrile CH3CN, and Mn-MOF1 material is obtained after solvothermal reaction.

7. The method for preparing the MOF material based on the metal manganese-oxygen chain unit according to claim 6, characterized in that: In the mixed solution, the concentration of manganese chloride tetrahydrate is 0.02-0.04 mol / L, the concentration of organic ligand H3TCA is 0.0053-0.0106 mol / L; the ratio of the added amounts of MnCl2·4H2O and DMF is (0.1-0.2) mmol:3 mL, and the volume ratio of DMF and CH3CN in the mixed solution is (1.5-2):

1.

8. The method for preparing the MOF material based on the metal manganese-oxygen chain unit according to claim 6, characterized in that: The temperature of the solvent thermal reaction is 120-125° C., and the reaction time is 1-2 days.

9. Use of the MOF material based on metal manganese-oxygen chain units as claimed in any one of claims 1 to 5 as a temperature sensor in the field of temperature sensing.

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