A kind of MOF material based on metal manganese-oxygen chain unit and its preparation method and application

Abstract

The application discloses a MOF material based on a metal manganese-oxygen chain unit and a preparation method and application thereof, and the chemical molecular formula of the MOF material based on the metal manganese-oxygen chain unit is [Mn3(TCA)2(H2O)2], wherein H3TCA is an organic ligand 4,4'4''-trimethyl aniline-3-carboxylic acid. The MOF material is formed by the metal manganese-oxygen chain unit and the organic ligand H3TCA, and has a three-dimensional porous structure with rhombic pores. The MOF material based on the metal manganese-oxygen chain unit has high thermal stability and good temperature sensing performance.

Description

Technical Field

[0001] This invention belongs to the field of crystalline porous material preparation and temperature sensing technology, specifically relating to a MOF material based on manganese-oxygen chain units and its preparation method and application. Background Technology

[0002] Temperature is a crucial parameter in natural sciences, industrial production, and daily life. Accurate temperature measurement is of great significance and research value for scientific research and production practices. Currently, there are many types of thermometers available. However, in some special situations, such as temperature measurement in low-temperature environments, high-temperature environments, microscopic systems, highly corrosive environments, or under strong electromagnetic conditions, traditional mercury thermometers and thermocouple thermometers often fall short of the requirements. Therefore, seeking new temperature detection methods with high sensitivity and high accuracy is of paramount importance.

[0003] Fluorescent temperature measurement, as a novel temperature detection technology, has attracted widespread 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 Frameworks, MOFs) possess unique framework structures and luminescent properties, especially rich emission sites, a wide emission wavelength range, structural tunability, and ease of functionalization, making them widely applicable in fields such as medical and health monitoring, environmental monitoring, and industrial automation. Utilizing the relationship between the fluorescence intensity ratio of the luminescent centers in the MOF structure and temperature to achieve temperature detection provides broad development space and prospects for the design and development of intelligent fluorescent temperature sensing materials. More importantly, the research on constructing highly stable and high-performance temperature sensor MOF materials based on polycarboxylic acid ligands in large π-delocalized systems urgently requires systematic research and development. Summary of the Invention

[0004] The first objective of this invention is to provide a MOF material based on a manganese-oxygen chain unit, wherein the chemical formula of the MOF material is [Mn3(TCA)2(H2O)2], named Mn-MOF1. The Mn-MOF1 material forms a three-dimensional porous structure with rhombic channels through the manganese-oxygen chain unit and the organic ligand H3TCA, where H3TCA is 4,4'4''-triphenylamine tricarboxylate, with the following structural formula:

[0005] .

[0006] Furthermore, the crystal structure of the Mn-MOF1 belongs to the monoclinic crystal system, with space group [missing information]. C 2 / cThe 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 .

[0007] Furthermore, in the Mn-MOF1 structure, the asymmetric unit comprises 1.5 crystal-independent Mn atoms. 2+ One deprotonated H3TCA ligand and one coordinated water molecule;

[0008] Among them, Mn 2+ It adopts a 6-coordinate octahedral coordination configuration, but has two coordination modes, Mn1 and Mn2. Mn1 coordinates with TCAs from 6 different deprotonated sites. 3- The ligand has 6 carboxyl oxygen atoms coordinated, and Mn2 is associated with 4 different deprotonated TCA atoms. 3- The ligand is coordinated with five carboxyl oxygen atoms and one oxygen atom of a water molecule.

[0009] Furthermore, in the structure of Mn-MOF1, Mn1 and Mn2 are connected by two carboxyl monodentate bridges and a carboxyl chelate-monodentate connection, while Mn2 and Mn2 share two carboxyl oxygens to form a one-dimensional metal manganese-oxygen chain unit.

[0010] Meanwhile, deprotonated H3TCA ligands are used μ 7- η 1 : η 1 : η 1 : η 2 : η 1 : η 2 Connecting metal ions; along b Along the axial direction, the three-dimensional structure of Mn-MOF1 contains rhombic channels with a size of approximately 10 × 10 Å. 2 .

[0011] Furthermore, the thermal stability of the Mn-MOF1 material reaches 430 °C. o C.

[0012] The present invention also provides a method for preparing the MOF material based on the manganese-oxygen chain unit, comprising the following steps:

[0013] Manganese chloride tetrahydrate (MnCl2·4H2O) and organic ligand H3TCA were added to a mixed solution of N,N-dimethylformamide (DMF) and acetonitrile (CH3CN), and the mixture was subjected to a solvothermal reaction to obtain Mn-MOF1 material.

[0014] Furthermore, 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 added MnCl2·4H2O to DMF is (0.1~0.2) mmol:3mL, and the volume ratio of DMF to CH3CN in the mixed solution is (1.5~2):1.

[0015] Furthermore, the temperature of the solvothermal reaction is 120~125 ℃, and the reaction time is 1~2 days.

[0016] Furthermore, the prepared Mn-MOF1 material was washed with DMF and CH3CN 3-5 times and then dried at room temperature for later use.

[0017] The present invention also provides the application of the MOF material based on the manganese-oxygen chain unit as a temperature sensor in the field of temperature sensing.

[0018] The beneficial effects of this invention: The MOF material structure of the manganese-oxygen chain unit of this invention is novel, and along the... b Viewed along the axis, the three-dimensional structure exhibits rhomboid channels formed by the metallic manganese-oxygen chain units and the organic ligand H3TCA, with a size of approximately 10 × 10 Å. 2 The thermal stability of the Mn-MOF1 material of this invention reaches 430 °C. o C. The Mn-MOF1 of the present invention has good application prospects as a fluorescent temperature sensor. Attached Figure Description

[0019] Figure 1 This is the asymmetric element diagram of Mn-MOF1.

[0020] Figure 2 This is a diagram of the manganese-oxygen chain unit of Mn-MOF1.

[0021] Figure 3 This diagram shows the connection mechanism of the organic ligand H3TCA for Mn-MOF1.

[0022] Figure 4 This is a three-dimensional structural diagram of Mn-MOF1.

[0023] Figure 5 The image shows the SEM morphology of Mn-MOF1.

[0024] Figure 6This is the X-ray powder diffraction pattern of Mn-MOF1.

[0025] Figure 7 The thermogravimetric curve of Mn-MOF1 is shown.

[0026] Figure 8 The fluorescence emission spectra of Mn-MOF1 and the organic ligand H3TCA are shown.

[0027] Figure 9 The fluorescence emission spectra of Mn-MOF1 at different temperatures are shown.

[0028] Figure 10 The graph shows the linear fit between the fluorescence emission intensity of Mn-MOF1 and temperature. Detailed Implementation

[0029] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments, but the scope of protection of the present invention is not limited to these embodiments.

[0030] Example 1

[0031] The preparation method of the MOF material with manganese-oxygen chain units in this embodiment is as follows:

[0032] MnCl2·4H2O (0.15 mmol) and organic ligand H3TCA (0.0265 mmol) were added to a mixed solution system of DMF (3 mL) and CH3CN (2 mL). The thermal reaction was carried out in a constant temperature drying oven at 125 °C for 1 day and then naturally cooled to room temperature. A large amount of yellow blocky crystals were obtained. After filtration and drying at room temperature, Mn-MOF1 material was prepared with a yield of 0.019 g and a yield of 63.1%.

[0033] Example 2

[0034] The preparation method of the MOF material with manganese-oxygen chain units in this embodiment is as follows:

[0035] MnCl2·4H2O (0.125 mmol) and organic ligand H3TCA (0.0265 mmol) were added to a mixed solution system of DMF (3 mL) and CH3CN (2 mL). The thermal reaction was carried out in a constant temperature drying oven at 120 °C for 2 days and then naturally cooled to room temperature to obtain a large amount of yellow blocky crystals. After filtration and drying at room temperature, Mn-MOF1 material was prepared with a yield of 0.015 g and a yield of 49.8%.

[0036] Example 3

[0037] The preparation method of the MOF material with manganese-oxygen chain units in this embodiment is as follows:

[0038] MnCl2·4H2O (0.2 mmol) and organic ligand H3TCA (0.0398 mmol) were added to a mixed solution system of DMF (3 mL) and CH3CN (2 mL). The thermal reaction was carried out in a constant temperature drying oven at 125 °C for 1 day and then naturally cooled to room temperature. A large amount of yellow blocky crystals were obtained. After filtration and drying at room temperature, Mn-MOF1 material was prepared with a yield of 0.022 g and a yield of 73.1%.

[0039] Example 4

[0040] The preparation method of the MOF material with manganese-oxygen chain units in this embodiment is as follows:

[0041] MnCl2·4H2O (0.25 mmol) and organic ligand H3TCA (0.0795 mmol) were added to a mixed solution system of DMF (5 mL) and CH3CN (2.5 mL). The thermal reaction was carried out in a constant temperature drying oven at 125 °C for 1 day, and then naturally cooled to room temperature to obtain a large amount of yellow blocky crystals. After filtration and drying at room temperature, Mn-MOF1 material was prepared with a yield of 0.050 g and a yield of 55.3%.

[0042] Example 5

[0043] The preparation method of the MOF material with manganese-oxygen chain units in this embodiment is as follows:

[0044] MnCl2·4H2O (0.1 mmol) and organic ligand H3TCA (0.0265 mmol) were added to a mixed solution system of DMF (3 mL) and CH3CN (2 mL). The thermal reaction was carried out in a constant temperature drying oven at 125 °C for 1 day and then naturally cooled to room temperature. A large amount of yellow blocky crystals were obtained. After filtration and drying at room temperature, Mn-MOF1 material was prepared with a yield of 0.01 g and a yield of 33.3%.

[0045] (1) Crystal data of Mn-MOF1 material

[0046] Crystal data were collected at 296(2) K using a Bruker D8 Quest CMOS single-crystal diffractometer with Mo-Kα (λ = 0.71073 Å) target rays monochromated by a graphite monochromator. Data processing and reconstruction were performed using the SAINT program. Structural analysis and refinement were performed using the SHELXL-97 program. The structural diagram is attached. Figure 1-4 Crystallographic data are shown in Table 1.

[0047] Table 1. Crystallographic data of the metal-organic framework material.

[0048]

[0049] Appendix Figure 1 The structural diagram shows that the asymmetric unit cell in the Mn-MOF1 material comprises 1.5 crystallographically independent Mn atoms. 2+ 1 TCA 3- The ligand consists of one coordinated water molecule. The symmetry opcodes in the diagram are: 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.

[0050] Appendix Figure 2 The structural diagram shows that in the Mn-MOF1 material, metallic Mn exists in two coordination modes, with Mn1 interacting with six different TCA groups. 3- The ligand has six carboxyl oxygen atoms coordinated to it, while Mn2 is associated with four different TCA groups. 3- The ligand has five carboxyl oxygen atoms coordinated to one oxygen atom of a water molecule. In Mn-MOF, Mn1 and Mn2 are connected by two carboxyl monodentate bridges and one carboxyl chelate-monodentate linker, while Mn2 and Mn2 share two carboxyl oxygen atoms to form a one-dimensional metal manganese-oxygen chain unit.

[0051] Appendix Figure 3 The structural diagram shows that the Mn-MOF1 material is connected to metallic manganese by organic ligands that have had three hydrogen atoms removed from their carboxyl groups.

[0052] Appendix Figure 4 The structural diagram shows that the three-dimensional structure of the Mn-MOF1 material, along... b When viewed along the axis, rhomboid channels with a size of approximately 10 × 10 Å are formed in the three-dimensional structure of Mn-MOF. 2 .

[0053] Appendix Figure 5 The SEM morphology images show that the Mn-MOF1 material is in bulk form with a size of 50-200 micrometers.

[0054] Appendix Figure 6 The X-ray powder diffraction pattern shows that the diffraction peaks of the Mn-MOF1 material and the simulated PXRD pattern of the single crystal structure are highly consistent, indicating that the Mn-MOF1 material has very high purity.

[0055] Appendix Figure 7The thermogravimetric curves show that the thermal stability analysis of the Mn-MOF1 material indicates that the material can be stable up to 430 °C.

[0056] (2) Solid-state fluorescence emission spectrum of Mn-MOF1 material in this embodiment

[0057] Solid-state fluorescence of Mn-MOF1 materials and the organic ligand H3TCA was investigated at room temperature (see Appendix). Figure 8 The organic ligand H3TCA exhibits a very strong fluorescence emission peak at 467 nm, while the Mn-MOF1 material exhibits a very strong fluorescence emission peak at 406 nm. Compared with the fluorescence emission peak of the organic ligand H3TCA, the Mn-MOF1 material shows a significant blue shift of about 61 nm. This phenomenon can be attributed to the fact that the carboxyl group of the organic ligand in the Mn-MOF1 structure remains rigid after coordination with the manganese ion, which raises the energy level between HOMO and LUMO, causing a significant blue shift in the Mn-MOF1 material.

[0058] (3) Fluorescence emission spectra of the Mn-MOF1 material at different temperatures in this embodiment

[0059] Due to the superior fluorescence properties and good stability of Mn-MOF1, its application in temperature sensing was investigated. For example... Figure 9 As shown, the temperature-dependent fluorescence spectroscopy results of Mn-MOF1 indicate that the fluorescence intensity gradually decreases with increasing temperature (80 K to 300 K), while the maximum emission spectrum remains unchanged with temperature, demonstrating the very strong stability of Mn-MOF1. Furthermore, the relationship between emission intensity and temperature (80 K to 300 K) shows a good linear correlation. R 2 =0.9758 (see appendix) Figure 10 This indicates that Mn-MOF1 material has great potential as a luminescent material in the field of low-temperature detection.

[0060] The foregoing has shown and described the basic principles and main features of the present invention, as well as its advantages. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A MOF material based on 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 rhombic channels through the metal manganese-oxygen chain unit and the organic ligand H3TCA. H3TCA is 4,4'4''-triphenylamine tricarboxylate, and its structural formula is as follows: ； In the Mn-MOF1 structure, the asymmetric unit comprises 1.5 crystal-independent Mn atoms. 2+ One deprotonated H3TCA ligand and one coordinated water molecule; Among them, Mn 2+ It adopts a 6-coordinate octahedral coordination configuration, but has two coordination modes, Mn1 and Mn2. Mn1 coordinates with TCAs from 6 different deprotonated sites. 3- The ligand has 6 carboxyl oxygen atoms coordinated, and Mn2 is associated with 4 different deprotonated TCA atoms. 3- The ligand has five carboxyl oxygen atoms coordinated to one oxygen atom of a water molecule; In the structure of Mn-MOF1, Mn1 and Mn2 are connected by two carboxyl monodentate bridges and one carboxyl chelate-monodentate connection, while Mn2 and Mn2 share two carboxyl oxygens to form a one-dimensional metal manganese-oxygen chain unit. Deprotonated H3TCA ligands are used μ 7- η 1 : η 1 : η 1 : η 2 : η 1 : η 2 Connecting Mn ions; along b Along the axial direction, the three-dimensional structure of Mn-MOF1 contains rhombic channels with a size of 10 × 10 Å. 2 .

2. The MOF material based on manganese-oxygen chain units according to claim 1, characterized in that: The crystal structure of the Mn-MOF1 belongs to the monoclinic crystal system, with space group [space group number missing]. 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 manganese-oxygen chain units according to claim 1, characterized in that: The thermal stability of the Mn-MOF1 material reaches 430. o C.

4. A method for preparing MOF material based on manganese-oxygen chain units as described in any one of claims 1-3, characterized in that: Includes the following steps: Manganese chloride tetrahydrate (MnCl2·4H2O) and organic ligand H3TCA were added to a mixed solution of N,N-dimethylformamide (DMF) and acetonitrile (CH3CN), and the mixture was subjected to a solvothermal reaction to obtain Mn-MOF1 material.

5. The method for preparing MOF materials based on manganese-oxygen chain units according to claim 4, 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 added MnCl2·4H2O to DMF is (0.1~0.2) mmol:3mL, and the volume ratio of DMF to CH3CN in the mixed solution is (1.5~2):

1.

6. The method for preparing MOF materials based on manganese-oxygen chain units according to claim 4, characterized in that: The solvothermal reaction is carried out at a temperature of 120-125 °C for 1-2 days.

7. The application of MOF material based on manganese-oxygen chain units as described in any one of claims 1-3 as a temperature sensor in the field of temperature sensing.

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