Application of metal fullerene-organic framework composite spinning functional material in air pressure measurement

Abstract

The invention relates to application of a metal fullerene-organic framework composite spinning functional material to air pressure measurement, and belongs to the technical field of metal fullerene composite materials. Loading the metal fullerene-organic framework composite spinning functional material into a quartz paramagnetic tube, adjusting the air pressure in the quartz paramagnetic tube, and collecting EPR signals of the material under different air pressures by using an electron paramagnetic resonance spectrometer; analyzing the peak heights of the EPR signals under different air pressures, and performing data fitting analysis by taking the air pressure values as abscissas and the peak heights as ordinates to obtain a relation equation; the method comprises the following steps: connecting a quartz paramagnetic tube filled with a metal fullerene-organic framework composite spinning functional material with a to-be-detected target system, and collecting an EPR signal; and substituting the peak height of the EPR signal into the relation equation to obtain an air pressure value of the target system. The self-spinning functional material can show excellent linear response in a low-vacuum region and a high-vacuum region, and meets the requirements for air pressure monitoring sensitivity and range in different scenes.

Description

Technical Field

[0001] The invention relates to application of a metal fullerene-organic framework composite spin functional material in air pressure measurement, belonging to the technical field of metal fullerene composite materials. Background Art

[0002] Air pressure, a physical quantity that reflects the rarefaction of air, holds significant application value in fields such as aerospace, industrial production, and environmental monitoring. With the development of society, methods for air pressure monitoring have been continuously refined and improved, resulting in the emergence of a wide range of air pressure sensors. Currently, air pressure measurement relies primarily on two types of technologies: mechanical pressure gauges and electronic sensors, primarily based on principles such as the piezoelectric effect, resistance change, or fiber optic sensing. The development of new air pressure measurement technologies will help expand its applications.

[0003] Organic framework materials are new porous crystalline materials constructed based on the concept of molecular engineering. They mainly include metal organic frameworks (MOFs) and covalent organic frameworks (COFs). These materials form a three-dimensional or two-dimensional ordered pore structure through the coordination bond between organic ligands and metal ions (MOFs) or the covalent bond between all-organic units (COFs). The pore size can be precisely adjusted in the nanometer range, and the specific surface area can reach 7000m 2 / g or more. The gas adsorption properties of organic framework materials are one of their most significant functional advantages. In gas storage applications, traditional pressure measurements only provide pressure data around the material and cannot measure the pressure within the pores of the organic framework. Therefore, the adsorption and desorption processes of gases within the material cannot be directly detected. Therefore, the development of in-situ, real-time pore pressure detection technology is needed.

[0004] Molecular spin probes are a class of functional molecules with unpaired electrons or specific magnetic properties. They can dynamically detect the structure and changes of the microscopic environment through techniques such as electron paramagnetic resonance (EPR), nuclear magnetic resonance (NMR) or magnetic resonance imaging (MRI). The core of this method is to use the magnetic characteristics of molecules themselves as "sensors" to reveal local physical and chemical information in materials, biological systems or chemical reactions. Molecular spin probe spin labeling technology, by introducing stable free radicals or paramagnetic atoms, gives molecules unpaired electrons, forming detectable magnetic signals. Molecular spin probes have the characteristics of high sensitivity, non-invasiveness, high temporal and spatial resolution, and have important application potential in materials science, medical imaging, environmental monitoring and other fields. As a "magnetic microscope", molecular spin probes are moving from basic research to widespread application. Among them, EPR is a unique technology specifically for the detection and characterization of paramagnetic substances, and is highly specific for free radical detection.

[0005] Metallofullerene spin-functional materials are nanoscale spherical molecules with sensitive electron spins. Due to the protection of the fullerene carbon cage, the electron spins within the cage are endowed with excellent chemical stability. The most notable feature of this type of molecule is that its electron spins are highly sensitive to external perturbations, which makes it show great application potential in the field of perception and sensing. For example, metallofullerene Sc3C2C 80 Paramagnetic molecules are representative spin-functional materials. Their unpaired single electrons are mainly located on the clusters inside the carbon cage and undergo hyperfine coupling with three Sc atoms. Hyperfine coupling splitting signals can be observed in the EPR spectrum. By analyzing the number, peak shape and intensity of the EPR spectrum, the interaction between the molecule and the environment can be explored. In particular, metallofullerene molecules have a size of less than 1 nm and can be implanted into the pores of organic framework materials. The gas adsorption of the material can be sensed by electron paramagnetic resonance (EPR) technology. Organic framework materials have highly ordered pore structures, adjustable pore sizes and rich functional group modification sites, making them ideal carriers of metallofullerene materials. The patent application CN115684239A submitted by the inventor of this application previously disclosed a metallofullerene electron spin probe and found that the effect of the interaction between metallofullerene and adsorbed gas in the pores of porous materials on the EPR signal can be used to analyze the gas adsorption capacity of porous materials, and then used to measure the gas adsorption performance of porous materials. However, when applying for the patent, the inventors had not discovered the changing relationship between the metal fullerene electron spin probe and air pressure, nor had they disclosed that it had properties related to air pressure measurement. Summary of the Invention

[0006] In view of this, the object of the present invention is to provide an application of a metallofullerene-organic framework composite spin functional material in air pressure measurement.

[0007] To achieve the above objectives, the technical solutions of the present invention are as follows.

[0008] An application of a metallofullerene-organic framework composite spin functional material in air pressure measurement includes the following steps:

[0009] The metallofullerene-organic framework composite spin functional material is placed in a quartz paramagnetic tube, the gas pressure in the quartz paramagnetic tube is adjusted, and the EPR signal of the material at different gas pressures is collected using an electron paramagnetic resonance spectrometer;

[0010] Analyze the EPR signal peak height under different gas pressures, use the gas pressure as the horizontal axis and the peak height as the vertical axis, perform data fitting analysis, and obtain the relationship equation;

[0011] A quartz paramagnetic tube containing a metal fullerene-organic framework composite spin functional material is connected to the target system to be measured to collect EPR signals; the EPR signal peak height is substituted into the relationship equation to obtain the gas pressure value of the target system.

[0012] Furthermore, the pressure adjustment range of the quartz paramagnetic tube is 1×10 5 Pa~1×10 -3 Pa.

[0013] Furthermore, the target system includes porous materials and a vacuum system.

[0014] Furthermore, the metal fullerene-organic framework composite spin functional material is composed of an organic framework material and metal fullerenes adsorbed in the pores of the organic framework material.

[0015] Furthermore, in the metallofullerene-organic framework composite spin functional material, the metallofullerene is Sc3C2C 80 Paramagnetic molecules; further, the mass fraction of metal fullerene is 1‰ to 20‰.

[0016] Furthermore, organic framework materials include metal-organic frameworks (MOFs) and covalent organic frameworks (COFs). Furthermore, the metal-organic frameworks include ZIF-8, NU-901, MOF-808, and MOF-177; and the covalent organic frameworks include Py-COF, Py-1P-COF, Py-2P-COF, and TpPa-1.

[0017] Furthermore, the metal fullerene-organic framework composite spin functional material is prepared by the following method, which includes: adding the organic framework material to the metal fullerene solution, fully soaking it to allow the metal fullerene to diffuse into the pores of the organic framework material, and after the soaking is completed, vacuum drying to obtain the metal fullerene-organic framework composite spin functional material.

[0018] Furthermore, the concentration of the metal fullerene solution is 10 -7 mol / L~10 -4 mol / L, the solvent is toluene, xylene, trimethylbenzene, chlorobenzene, o-dichlorobenzene or trichlorobenzene.

[0019] Furthermore, the soaking time is 1 to 7 days.

[0020] Beneficial effects

[0021] The present invention provides an application of a metallofullerene-organic framework composite spin-functional material for air pressure measurement. The inventors discovered that the metallofullerene-organic framework composite spin-functional material exhibits regular EPR signal variations under different air pressure conditions, exhibiting an exponential dependence. A linear equation is obtained by fitting the EPR signal peak height measured for the target system into this equation to obtain the air pressure of the target system. Different composite spin-functional materials exhibit different dependencies between EPR signal peak height and air pressure, resulting in different fitted equations. In practical applications, data entry and calculations should be tailored to the type of composite material used.

[0022] Organic framework materials possess highly ordered pore structures and tunable pore sizes. Their nanoscale confinement allows them to accommodate and stabilize molecular probes embedded with metallofullerenes. Within the nanopores, the adsorption, diffusion, and movement of gas molecules interact closely with the metallofullerenes embedded within the pores, triggering a spin signal response from the metallofullerenes. This signal can then be used to detect the gas pressure within the pores of the porous material, enabling in situ monitoring of gas adsorption and desorption within the pores. This type of metallofullerene-organic framework composite spin-functionalized material, capable of real-time in situ measurement of gas pressure within the framework material's pores, will have transformative applications.

[0023] This application can also be extended to conventional vacuum systems, specifically for testing negative pressure systems under working conditions. This involves connecting the system under test to a quartz tube containing a spin-composite material, collecting EPR spectra, and analyzing the data to determine the system's vacuum level. Due to the metallofullerene's sensitive sensitivity to its environment, the spin signal exhibits excellent linear response in both low and high vacuum regions, meeting the sensitivity and range requirements for pressure monitoring in various scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Sc3C2C prepared in Example 1 of the present invention 80 Optical photograph of @Py-COF spin-functional material.

[0025] Figure 2 Sc3C2C prepared in Example 2 of the present invention 80 Optical photograph of @Py-1P-COF spin-functional material.

[0026] Figure 3 Sc3C2C prepared in Example 3 of the present invention 80 Optical photograph of @ZIF-8 spin-functional material.

[0027] Figure 4 Schematic diagram of the structure of the device used in Example 4 of the present invention.

[0028] Figure 5Sc3C2C described in Example 1 80 @Py-COF spin functional material response to gas pressure (a) and the linear relationship between gas pressure and EPR peak height (b).

[0029] Figure 6 Sc3C2C described in Example 2 80 @Py-1P-COF spin functional material response to gas pressure (a) and the linear relationship between gas pressure and EPR peak height (b).

[0030] Figure 7 Sc3C2C described in Example 3 80 @ZIF-8 spin functional material response to air pressure (a) and the linear relationship between air pressure and EPR peak height (b). DETAILED DESCRIPTION

[0031] The present invention will be further described in detail below with reference to specific examples. Unless otherwise specified, the experimental methods used in the following examples are conventional methods; the reagents and materials used in the following examples are all commercially available unless otherwise specified.

[0032] The invention discloses an application of a metallofullerene-organic framework composite spin functional material in air pressure measurement. The application steps include: loading the metallofullerene-organic framework composite spin functional material into a quartz paramagnetic tube, then placing the tube in an electron paramagnetic resonance spectrometer, connecting the quartz paramagnetic tube to a vacuum pump and a vacuum gauge via an air pipe, controlling different air pressures via a regulating valve, and obtaining EPR signals by testing at different air pressures.

[0033] In the test, the pressure range can be 1×10 5 Pa to 1×10 -3 Between Pa.

[0034] The test analyzed the EPR signal peak heights at different pressures, with pressure as the horizontal axis and peak height as the vertical axis, and performed a data fitting analysis. The experimental results showed that the composite spin-functional material exhibited regular EPR signal variations under different pressure conditions, exhibiting an exponential dependence. The fitting yielded a linear equation. Substituting the measured EPR signal peak height of the spin-functional material in the target system into this equation, the target system's pressure value was obtained.

[0035] In the test, different composite spin functional materials have different dependencies between EPR signal peak height and gas pressure value, so different relationship equations will be fitted. In actual application, data should be input and calculated according to the type of composite material used.

[0036] The metal fullerene-organic framework composite spin functional material is composed of embedded metal fullerene and organic framework material.

[0037] The metal fullerene is Sc3C2C 80 Paramagnetic molecules.

[0038] The mass fraction of the metal fullerene in the metal fullerene-organic framework composite spin functional material is 1‰ to 20‰.

[0039] The organic framework materials include two major systems: metal organic frameworks (MOFs) materials and covalent organic frameworks (COFs) materials.

[0040] The metal-organic framework compound is a metal-organic framework compound material with a three-dimensional ordered porous structure formed by organic molecules such as organic carboxylic acids containing at least one multidentate functional group as ligands and metal ions as the center; the metal ions can be metal ions such as Zr, Zn, Mn, Mg, etc.; the metal-organic framework material can specifically be: ZIF-8, NU-901, MOF-808, MOF-177, etc.

[0041] The covalent organic framework compound is a highly ordered two-dimensional porous crystalline material formed by connecting two formyl groups and two amino groups in a single pyrene core molecule through intermolecular self-condensation; the covalent organic framework material can specifically be: Py-COF, Py-1P-COF, Py-2P-COF, TpPa-1, etc.

[0042] The metal fullerene-organic framework composite spin functional material is prepared according to a method comprising the following steps: preparing a metal fullerene solution of a certain concentration, immersing an appropriate amount of organic framework material in the metal fullerene solution, fully immersing the material to allow the metal fullerene to diffuse into the pores of the organic framework material, and vacuum drying after the immersion to remove solvent molecules, thereby finally obtaining the metal fullerene-organic framework composite material.

[0043] The metallofullerene solution uses endohedral metallofullerene as solute, and the solvent can be one of toluene, xylene, trimethylbenzene, chlorobenzene, o-dichlorobenzene, and trichlorobenzene.

[0044] The concentration of the metal fullerene solution can be 10 -7 mol / L to 10 -4 mol / L.

[0045] The soaking time is 1 to 7 days.

[0046] Example 1

[0047] Sc3C2C 80Synthesis of Py-COF spin functional materials: 2 mg of Py-COF was weighed and immersed in 5.76×10 -5 mol / LSc3C2C 80 After 7 days of sufficient adsorption, the solid was taken out and rinsed with toluene and dried in vacuo. 80 The mass fraction of Sc3C2C is 14.7‰. 80 Optical photos of @Py-COF composite materials are shown in Figure 2. Figure 1 shown.

[0048] Example 2

[0049] Sc3C2C 80 Synthesis of @Py-1P-COF spin functional material: 2 mg of Py-1P-COF was weighed and immersed in 5.76×10 - 5 mol / L Sc3C2C 80 After 7 days of adsorption, the solid was taken out and rinsed with toluene and dried in vacuo. 80 The mass fraction of Sc3C2C is 9.67‰. 80 Optical photos of @Py-1P-COF composite materials Figure 2 .

[0050] Example 3

[0051] Sc3C2C 80 @ Synthesis of ZIF-8 spin functional materials: 10 mg ZIF-8 was weighed and immersed in 2.88×10 -5 mol / LSc3C2C 80 After 7 days of adsorption, the solid was taken out and rinsed with toluene and dried in vacuo. 80 The mass fraction of Sc3C2C is 2.86‰. 80 Optical photos of ZIF-8 composite materials are shown in Figure 2. Figure 3 .

[0052] Example 4

[0053] Detection of air pressure by spin functional materials: Place the spin functional material in a quartz paramagnetic tube, place the quartz paramagnetic tube in the resonant cavity of an electron paramagnetic resonance spectrometer, and connect the quartz paramagnetic tube to a vacuum pump and a vacuum gauge through an air pipe, such as Figure 4 As shown in the figure, different air pressures are controlled by regulating valves, and EPR signals are obtained by testing at different air pressures.

[0054] Figure 5-7 Sc3C2C 80 @Py-COF、Sc3C2C 80 @Py-1P-COF and Sc3C2C 80 The EPR spectrum of @ZIF-8 changes at different pressures. In this example, the pressure was controlled in the range of 1-1000 mbar. The measured EPR signal peak height was analyzed and plotted as a function of pressure. The EPR peak height exhibited a linear response to pressure. A linear fit was performed on the data to obtain an equation for the relationship between EPR peak height and pressure. Based on this linear equation, in practice, the pressure of the target system can be obtained by substituting the measured EPR signal peak height of the spin-functional material into this equation.

[0055] Example 5

[0056] will be loaded with Sc3C2C 80 A quartz paramagnetic tube containing the @Py-COF material was connected to the vacuum system to be tested via an air pipe. The electron paramagnetic resonance (EPR) signal from the material was collected, yielding a peak-to-peak height of 22.6. Substituting this peak-to-peak height into the standard fitting curve established in Example 4: y = 11.32 + 30 * exp(-(x + 69.99) / 113.25), the solution yielded a pressure of approximately 40.8 mbar. To verify the feasibility, a digital vacuum gauge was then used to measure the pressure, which showed a value of 40.6 mbar, with an error of less than 1%.

[0057] Example 6

[0058] will be loaded with Sc3C2C 80 A paramagnetic tube for the @Py-1P-COF material was connected to the vacuum system to be tested via an air pipe. The EPR signal of the material was collected. The peak-to-peak height of the measured EPR signal was 8.5. Substituting the corresponding standard curve fitting formula from Example 4: y = 4.66 + 13.43 * exp(-(x + 2.73) / 68.11), the system pressure at this point was calculated to be 82.5 mbar. The system pressure was then measured using a digital vacuum gauge, which showed a pressure of 83 mbar, within 1%.

[0059] Example 7

[0060] will be loaded with Sc3C2C 80A paramagnetic tube containing the ZIF-8 material was connected to the vacuum system to be tested via an air pipe. The EPR signal of the material was collected, and the peak-to-peak height of the measured EPR signal was 3.2. Substituting this value into the corresponding standard fitting curve in Example 4: y = 1.77 + 2*exp(-(x - 30.72) / 412.94), the system pressure was calculated to be approximately 170 mbar. The system pressure was then measured using a digital vacuum gauge, which showed a pressure of 171.2 mbar, with a calculated error of less than 1%.

[0061] In summary, the invention includes but is not limited to the above embodiments. Any equivalent replacement or partial improvement made under the spirit and principle of the present invention shall be deemed to be within the scope of protection of the present invention.

Claims

1. Application of a metallofullerene-organic framework composite spin functional material in air pressure measurement, characterized by: The application steps include: The metallofullerene-organic framework composite spin functional material is placed in a quartz paramagnetic tube, the gas pressure in the quartz paramagnetic tube is adjusted, and the EPR signal of the material at different gas pressures is collected using an electron paramagnetic resonance spectrometer; Analyze the peak height of EPR signals under different gas pressures, use gas pressure as the horizontal axis and peak height as the vertical axis, perform data fitting analysis, and obtain the relationship equation; A quartz paramagnetic tube containing a metal fullerene-organic framework composite spin functional material is connected to the target system to be measured to collect EPR signals; the EPR signal peak height is substituted into the relationship equation to obtain the gas pressure value of the target system.

2. The use of a metallofullerene-organic framework composite spin functional material in air pressure measurement according to claim 1, characterized in that: The gas pressure adjustment range in the quartz paramagnetic tube is 1×10 5 Pa~1×10 -3 Pa.

3. The use of a metallofullerene-organic framework composite spin functional material in air pressure measurement according to claim 1, characterized in that: The target system includes porous materials and a vacuum system.

4. The use of a metallofullerene-organic framework composite spin functional material in air pressure measurement according to claim 1, characterized in that: The metal fullerene-organic framework composite spin functional material consists of an organic framework material and metal fullerenes adsorbed in the pores of the organic framework material.

5. The use of a metallofullerene-organic framework composite spin functional material in air pressure measurement according to claim 1 or 4, characterized in that: In the metal fullerene-organic framework composite spin functional material, the metal fullerene is Sc3C2C 80 Paramagnetic molecules.

6. The use of a metallofullerene-organic framework composite spin functional material in air pressure measurement according to claim 4, characterized in that: The mass fraction of metal fullerene is 1‰~20‰.

7. Use of a metallofullerene-organic framework composite spin functional material in air pressure measurement according to claim 1 or 4, characterized in that: Organic framework materials include metal-organic framework materials and covalent organic framework materials.

8. The use of a metallofullerene-organic framework composite spin functional material in air pressure measurement according to claim 7, characterized in that: The metal organic framework materials include ZIF-8, NU-901, MOF-808, and MOF-177; the covalent organic framework materials include Py-COF, Py-1P-COF, Py-2P-COF, and TpPa-1.

9. The use of a metallofullerene-organic framework composite spin functional material in air pressure measurement according to claim 4, characterized in that: The metal fullerene-organic framework composite spin functional material is prepared by the following method, which includes: adding the organic framework material to the metal fullerene solution, fully soaking it to allow the metal fullerene to diffuse into the pores of the organic framework material, and after the soaking is completed, vacuum drying to obtain the metal fullerene-organic framework composite spin functional material.

10. The use of a metallofullerene-organic framework composite spin functional material in air pressure measurement according to claim 9, characterized in that: The concentration of the metal fullerene solution is 10 -7 mol / L~10 -4 mol / L, the solvent is toluene, xylene, trimethylbenzene, chlorobenzene, o-dichlorobenzene or trichlorobenzene; And / or, the soaking time is 1 to 7 days.

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