A tripod-gadolinium-protoporphyrin IX and its preparation method and application

Abstract

The present invention discloses a tripod-gadolinium-protoporphyrin IX and its preparation method and application, belonging to the field of inorganic chemistry. First, gadolinium-protoporphyrin IX was prepared by coordinating protoporphyrin IX with gadolinium, and it was found that it was also unstable in the aqueous phase. In order to improve the stability of gadolinium-protoporphyrin IX in the aqueous phase, the present invention provides a method for coordinating gadolinium in gadolinium-protoporphyrin IX with a tripod molecule, and a stable tripod-gadolinium-protoporphyrin IX in the aqueous phase was obtained. Among them, the tripod molecule is sodium(cyclopentadienyl)tris(dimethylphosphiteoxy)cobalt(I). Further, the tripod-gadolinium-protoporphyrin IX was used for ratio sensing determination of dissolved oxygen, and it has good response sensitivity, response time and repeatability as a sensor.

Description

Technical Field

[0001] The present invention belongs to the field of inorganic chemistry, and particularly relates to a tripod-gadolinium-protoporphyrin IX, a preparation method thereof, and an application thereof. Background Art

[0002] Disclosing the information of this background art section is only intended to enhance the understanding of the overall background of the present invention, and is not necessarily to be regarded as an admission or any form of implication that this information constitutes the prior art already known to those of ordinary skill in the art.

[0003] Metal porphyrins are widely used in the fields of biomedicine, photocatalysis, analytical chemistry, etc. Among them, metal porphyrins with phosphorescence emission can be used to detect analytes such as oxygen and glucose. Platinum and palladium porphyrins are the most used porphyrins because they have a long triplet lifetime and a phosphorescence emission quantum yield. However, their emission peaks are around 650 nm, which has not reached the optical window of tissues. Lanthanide metal porphyrins, such as gadolinium porphyrin and lutetium porphyrin, have also been reported to have phosphorescence emission. Compared with platinum-based metal porphyrins, the phosphorescence emission wavelength of gadolinium porphyrin exceeds 700 nm. In addition, lanthanide metals have the advantages of being more easily obtained and lower in price than platinum-based metals. For example, the price of gadolinium chloride is about 1 / 10 of the price of palladium chloride.

[0004] However, gadolinium porphyrin is structurally unstable in phosphate buffer solution (pH = 7.2). This may be because gadolinium usually has 7-8 coordinations, and only 4 positions are coordinated by the 4 nitrogen atoms of the porphyrin. The remaining positions may be occupied by other groups in the phosphate buffer solution, resulting in the destruction of the symmetry of gadolinium porphyrin and even the dissociation of gadolinium ions from the porphyrin. Summary of the Invention

[0005] In order to solve the deficiencies of the prior art, the purpose of the present invention is to provide a tripod-gadolinium-protoporphyrin IX, a preparation method thereof, and an application thereof. First, gadolinium-protoporphyrin IX was obtained by coordinating protoporphyrin IX with gadolinium, and it was found that it is unstable in the aqueous phase. In order to improve the stability of gadolinium-protoporphyrin IX in the aqueous phase, the present invention provides a method for coordinating gadolinium in gadolinium-protoporphyrin IX with a tripod molecule, obtaining a stable tripod-gadolinium-protoporphyrin IX in the aqueous phase, and further using the tripod-gadolinium-protoporphyrin IX to perform ratio sensing determination of dissolved oxygen.

[0006] In order to achieve the above purpose, the technical solution of the present invention is as follows:

[0007] In the first aspect, the present invention provides a tripod-gadolinium-protoporphyrin IX, and the structure of the tripod-gadolinium-protoporphyrin IX is shown in formula (II);

[0008] Formula (II).

[0009] The tripod-gadolinium-protoporphyrin IX has a stable structure in phosphate buffer solution.

[0010] Research has found that gadolinium-protoporphyrin IX has an unstable structure in phosphate buffer solution, and its luminescence and absorption spectra change after adding phosphate buffer solution, gradually becoming the characteristics of protoporphyrin IX. The reason for the breakage is mainly that the oxygen atom in the phosphate group in the phosphate system coordinates with gadolinium in gadolinium-protoporphyrin IX to form a gadolinium-oxygen bond, causing the gadolinium-nitrogen bond between gadolinium and protoporphyrin IX to break, resulting in the dissociation of the metal in the metal complex. The oxygen atom in the tripod molecule is used to pre-coordinate with gadolinium in gadolinium-protoporphyrin IX, and the tripod molecule does not cause the breakage of the gadolinium-nitrogen bond, finally forming the tripod-gadolinium-protoporphyrin IX molecule. After entering the system containing phosphate groups, this molecule will no longer coordinate with exogenous substances in the system, so the stability of the structure can be ensured.

[0011] In a second aspect, the present invention provides a method for preparing the tripod-gadolinium-protoporphyrin IX described in the first aspect, comprising the following steps:

[0012] Mix an organic solvent solution containing gadolinium-protoporphyrin IX with an organic solvent solution containing a tripod molecule and stir at room temperature;

[0013] The structure of the gadolinium-protoporphyrin IX is shown in formula (I):

[0014] Formula (I).

[0015] In one or more embodiments, the tripod molecule is sodium(cyclopentadienyl)tris(dimethylphosphite)cobalt(I).

[0016] In one or more embodiments, the concentration of the organic solvent solution containing gadolinium-protoporphyrin IX is 1 - 3 mM, the concentration of the organic solvent solution containing the tripod molecule is 2 - 4 mM, and the volume ratio of the organic solvent solution of gadolinium-protoporphyrin IX to the organic solvent solution of the tripod is 1:(0.9 - 1.1).

[0017] In one or more embodiments, the organic solvent is methanol or ethanol.

[0018] In one or more embodiments, the stirring time is 12 - 14 h.

[0019] In one or more embodiments, the preparation method of gadolinium-protoporphyrin IX comprises the following steps:

[0020] Using protoporphyrin IX and gadolinium salt as raw materials, imidazole as a thermal solvent, reacting by a solvothermal method, and cooling after the reaction to obtain a crystalline solid containing gadolinium-protoporphyrin IX;

[0021] Dissolve the crystalline solid containing gadolinium-protoporphyrin IX in an organic solvent and purify it by dialysis using the organic solvent to obtain gadolinium-protoporphyrin IX.

[0022] Protoporphyrin IX is a porphyrin with wide applications, low price, and certain water solubility.

[0023] In one or more embodiments, the gadolinium salt is gadolinium chloride or gadolinium nitrate.

[0024] In one or more embodiments, the hot solvent used in the solvothermal reaction is imidazole. The amount of the hot solvent used does not need to be particularly limited as long as it is sufficient to enable the reaction to proceed fully. In the embodiments of the present invention, the molar ratio of imidazole to protoporphyrin IX is (3000 - 5000):1, preferably (3500 - 4500):1.

[0025] In one or more embodiments, the molar ratio of protoporphyrin IX to the gadolinium salt is 1:(9 - 11).

[0026] In one or more embodiments, the temperature of the solvothermal reaction is 120 - 140 °C, and the time is 6 - 9 h, preferably 6 - 8 h. When the temperature exceeds 140 °C, the structure of the porphyrin will be damaged. For example, when the temperature exceeds 200 °C, some side chains (ethers or carboxyl groups) of the porphyrin may be damaged, resulting in the undetectability of the gadolinium porphyrin product in the mass spectrum; if the time is too short, it is not conducive to the coordination of gadolinium ions and porphyrin, resulting in incomplete coordination and too low yield of the metal porphyrin.

[0027] In one or more embodiments, the organic solvent is methanol or ethanol.

[0028] In one or more embodiments, the number of dialysis purifications is 3 - 5 times, and the time for each time is 2 - 3 hours.

[0029] In a third aspect, the present invention provides the application of the tripod-gadolinium-protoporphyrin IX described in the first aspect or the tripod-gadolinium-protoporphyrin IX prepared by the method described in the second aspect in the preparation of oxygen sensor materials.

[0030] Preferably, the application in a phosphate system.

[0031] In a fourth aspect, a method for measuring oxygen by the ratio method, the method uses the tripod-gadolinium-protoporphyrin IX described in the first aspect as an oxygen concentration detection sensor, and includes the following steps:

[0032] Place the tripod-gadolinium-protoporphyrin IX in a phosphate buffer solution, and pass a nitrogen gas stream above the liquid surface of the solution, and measure its luminescence spectra before and after passing nitrogen; use phosphorescence as the oxygen sensing signal and fluorescence as the reference signal, and realize the detection of oxygen concentration based on the phosphorescence-fluorescence intensity ratio.

[0033] In one or more embodiments, the time for introducing nitrogen gas is 3 to 5 minutes. It is found that for the methanol / phosphate buffer solution system of tripod-gadolinium-protoporphyrin IX, the fluorescence of the system remains unchanged, while the phosphorescence shows a huge enhancement within 3 minutes. After stopping the introduction of nitrogen gas, the phosphorescence will rapidly decline, and after introducing nitrogen gas again, the phosphorescence can recover again.

[0034] Preferably, the wavelength of the excitation light source is 350 - 450 nm, preferably 405 nm.

[0035] Preferably, the emission wavelength of fluorescence is 610 - 640 nm, and the emission wavelength of phosphorescence is 700 - 740 nm. Preferably, the emission wavelength of fluorescence is 620 - 630 nm, and the emission wavelength of phosphorescence is 700 - 730 nm.

[0036] The ratio method is based on the phosphorescence-fluorescence intensity ratio to achieve phosphorescence-fluorescence ratio detection. Using phosphorescence as the oxygen sensing signal and fluorescence as the reference signal, real-time detection of oxygen concentration is realized.

[0037] In one or more embodiments, tripod-gadolinium-protoporphyrin IX is first dissolved in an organic solvent and then placed in a phosphate buffer solution.

[0038] Preferably, the volume ratio of the organic solvent solution containing tripod-gadolinium-protoporphyrin IX to the phosphate buffer solution is 1:(0.9 - 1.1).

[0039] Preferably, the organic solvent is methanol or ethanol.

[0040] Preferably, the concentration of the organic solvent solution containing tripod-gadolinium-protoporphyrin IX is 40 - 250 μM.

[0041] Preferably, the concentration of the phosphate buffer solution is 0.01 - 0.02 M.

[0042] One or some of the above technical solutions have the following advantages or beneficial effects:

[0043] (1) The tripod-gadolinium-protoporphyrin IX provided by the present invention has a stable structure in the presence of phosphate buffer solution. When gadolinium-protoporphyrin IX is in the presence of phosphate buffer solution, its fluorescence spectrum will rapidly transform into the fluorescence characteristics of protoporphyrin IX within several hours, that is, strong fluorescence, and its ultraviolet-visible absorption spectrum will also completely transform into the absorption characteristics of protoporphyrin IX after several days, that is, the absorption of the Soret band (350 - 450 nm) becomes broader, and the number of absorption peaks in the Q band (450 - 700 nm) increases. However, the molecular tripod-gadolinium-protoporphyrin IX with a coordinating tripod has a stable structure in the presence of phosphate buffer solution, specifically manifested as follows: no observable change in fluorescence within 24 hours, the ultraviolet-visible absorption spectrum still shows the absorption characteristics of metal porphyrin after 6 days, and the mass spectrometry after 3 days shows that the peak position of m / z and the isotope peak shape are still consistent with those of gadolinium-protoporphyrin IX.

[0044] (2) By using the tripod-gadolinium-protoporphyrin IX molecule proposed by the present invention, the detection of oxygen in water can be achieved. It is found that when nitrogen is passed through the methanol / phosphate buffer solution system of tripod-gadolinium-protoporphyrin IX, the fluorescence of the system remains unchanged, while the phosphorescence shows a huge enhancement within 3 minutes. After stopping passing nitrogen, the phosphorescence will rapidly decline, and when nitrogen is passed again, the phosphorescence can recover again. It has good response sensitivity, response time and repeatability. Brief Description of the Drawings

[0045] The specification drawings forming a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention.

[0046] Figure 1 It is the mass spectrometry and theoretical mass spectrometry diagrams of gadolinium-protoporphyrin IX prepared in Example 1 of the present invention; wherein, (a) is the mass spectrometry and (b) is the theoretical mass spectrometry;

[0047] Figure 2 It is the luminescence spectrum after adding phosphate buffer solution in Example 1 of the present invention; wherein, (a) is the luminescence spectrum at different times after adding phosphate buffer solution to the methanol solution of gadolinium-protoporphyrin IX, and (b) is the luminescence spectrum of protoporphyrin IX in methanol / phosphate buffer solution;

[0048] Figure 3 It is the ultraviolet-visible absorption spectrum diagram of gadolinium-protoporphyrin IX in different solutions in Example 1 of the present invention; wherein, (a) is the ultraviolet-visible absorption spectrum of gadolinium-protoporphyrin IX in methanol solution, (b) is the ultraviolet-visible absorption spectrum of gadolinium-protoporphyrin IX methanol solution after adding phosphate buffer solution for 3 days, and (c) is the ultraviolet-visible absorption spectrum of protoporphyrin IX in methanol / phosphate buffer solution;

[0049] Figure 4This is the mass spectrum and theoretical mass spectrum of tripod-gadolinium-protoporphyrin IX in Example 2 of the present invention; wherein, (a) is the mass spectrum and (b) is the theoretical mass spectrum.

[0050] Figure 5 This is the luminescence spectrum of tripod-gadolinium-protoporphyrin IX at different times after adding phosphate buffer solution to the methanol solution in Example 2 of the present invention.

[0051] Figure 6 This is the ultraviolet-visible absorption spectrum of tripod-gadolinium-protoporphyrin IX in different solutions in Example 2 of the present invention; wherein, (a) is the ultraviolet-visible absorption spectrum of tripod-gadolinium-protoporphyrin IX in methanol solution, and (b) is the ultraviolet-visible absorption spectrum of tripod-gadolinium-protoporphyrin IX in methanol solution after adding phosphate buffer solution for 6 days.

[0052] Figure 7 This is the mass spectrum of tripod-gadolinium-protoporphyrin IX in methanol solution after adding phosphate buffer solution for 3 days in Example 2 of the present invention.

[0053] Figure 8 This is the luminescence spectrum of tripod-gadolinium-protoporphyrin IX before and after purging with nitrogen after storing in methanol / phosphate buffer solution for 5 h in Example 3 of the present invention. Detailed implementation manners

[0054] It should be noted that PpIX is protoporphyrin IX; Gd-PpIX is gadolinium-protoporphyrin IX; Gd-PpIX-L OMe is tripod-gadolinium-protoporphyrin IX.

[0055] Platinum and palladium porphyrins are the most widely used phosphorescent metal porphyrins. Compared with platinum-based metal porphyrins, the phosphorescence emission wavelength of gadolinium porphyrin exceeds 700 nm. In addition, lanthanide metals have advantages such as easier availability and lower price compared to platinum-based metals. However, gadolinium porphyrin is structurally unstable in phosphate buffer solution (pH = 7.2).

[0056] To solve the above problems, the design concept of the present invention is as follows: First, gadolinium-protoporphyrin IX was synthesized using a gadolinium salt and protoporphyrin IX, and the synthesized gadolinium-protoporphyrin IX was characterized by mass spectrometry. It was found through experiments that gadolinium-protoporphyrin IX can stably exist in methanol. However, when a phosphate buffer solution is added to this solution, the emission spectrum gradually changes to the fluorescence characteristics of protoporphyrin IX, and the measurement of the ultraviolet-visible absorption spectrum also confirms that phosphate will destroy the structure of gadolinium-protoporphyrin IX. The present invention pre-coordinates gadolinium-protoporphyrin IX with a tripod ligand molecule. In this way, the gadolinium in gadolinium-protoporphyrin IX will no longer be coordinated in the presence of phosphate. The synthesized tripod-gadolinium-protoporphyrin IX was characterized by mass spectrometry. The measurement of the emission spectrum found that the luminescence characteristics of tripod-gadolinium-protoporphyrin IX hardly changed within 24 hours in methanol / phosphate buffer solution, and the ultraviolet-visible absorption spectrum and mass spectrometry also confirmed that tripod-gadolinium-protoporphyrin IX can stably exist in a system containing a phosphate buffer solution. Finally, tripod-gadolinium-protoporphyrin IX was used for a preliminary analysis of different oxygen concentrations.

[0057] The implementation method is as follows: (1) Using protoporphyrin IX and a gadolinium source as raw materials and imidazole as a solvent, gadolinium ions were introduced into the porphyrin ring by the solvothermal method. After cooling, a crystalline solid containing gadolinium-protoporphyrin IX was obtained; (2) The obtained gadolinium-protoporphyrin IX was dissolved in methanol and dialyzed and purified with methanol as a solvent to remove excess gadolinium source, imidazole and other impurities; (3) The purified product was mixed with a solution of the tripod ligand (using methanol as a solvent) in a ratio of 1:1 and stirred for a certain time to prepare tripod-gadolinium-protoporphyrin IX.

[0058] In order to enable those skilled in the art to more clearly understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below in conjunction with specific embodiments.

[0059] Example 1

[0060] Using protoporphyrin IX and gadolinium chloride as raw materials, by the solvothermal method, with imidazole as the thermal solvent, the molar ratio of imidazole to protoporphyrin IX was 4000:1, the molar ratio of protoporphyrin IX to gadolinium chloride was 1:10, the temperature of the solvothermal reaction was 140 °C, and the time of the solvothermal reaction was 8 hours to synthesize gadolinium-protoporphyrin IX. After the reaction ended, it was allowed to cool naturally to room temperature to obtain a crystalline solid containing gadolinium-protoporphyrin IX. The structure of gadolinium-protoporphyrin IX is shown in formula (I);

[0061] Formula (I).

[0062] The obtained crystalline solid was dissolved in methanol, which would contain gadolinium-protoporphyrin IX, imidazole, Gd 3+ , Cl -Components such as these were dialyzed and purified 5 times using methanol as the solvent to remove components with smaller molecular weights such as imidazole, Gd 3+ , Cl - etc., and characterized using mass spectrometry. As Figure 1 shown, the experimental mass spectrum of gadolinium-protoporphyrin IX measured was highly consistent with its theoretical mass spectrum, indicating the successful synthesis of gadolinium-protoporphyrin IX.

[0063] The dialyzed and purified gadolinium-protoporphyrin IX was diluted to a concentration of 250 μM and mixed with a phosphate buffer solution at a concentration of 0.01 M in a volume ratio of 1:1.

[0064] As Figure 2 shown in (a) of Figure 2 , significant changes occurred in the luminescence spectra of the gadolinium-protoporphyrin IX methanol solution at different times after adding the phosphate buffer solution.

[0065] As Figure 3 shown, the ultraviolet-visible absorption spectrum of gadolinium-protoporphyrin IX in methanol solution was completely different from that of protoporphyrin IX, with a narrower Soret band (350 - 450 nm) and the number of peaks in the Q band (450 - 700 nm) reduced to 2. However, after 3 days of adding the phosphate buffer solution, the characteristics of both the Soret band and the Q band were consistent with those of protoporphyrin IX.

[0066] Example 2

[0067] Gadolinium-protoporphyrin IX obtained in Example 1 was mixed with a solution of a tripod ligand (using methanol as the solvent) in a ratio of 1:1 and stirred for a certain time to prepare tripod-gadolinium-protoporphyrin IX.

[0068] As Figure 4 shown, the experimental mass spectrum of tripod-gadolinium-protoporphyrin IX measured was highly consistent with its theoretical mass spectrum, indicating the successful synthesis of tripod-gadolinium-protoporphyrin IX.

[0069] Phosphate buffer solution (0.01 M) was added to the methanol solution of tripod-gadolinium-protoporphyrin IX (40 μM), and the change in the luminescence spectrum over time was detected. As Figure 5 shown, no significant changes occurred in the luminescence spectrum within 24 h, preliminarily indicating that the tripod can stabilize gadolinium-protoporphyrin IX.

[0070] Meanwhile, the ultraviolet-visible absorption spectrum of tripod-gadolinium-protoporphyrin IX stored in methanol / phosphate buffer solution for several days was measured. As Figure 6As shown, it was found that the UV-visible absorption spectra of the tripod-gadolinium-protoporphyrin IX after being stored for 6 days were completely identical to those of the tripod-gadolinium-protoporphyrin IX in methanol, which confirmed that the tripod-gadolinium-protoporphyrin IX did not transform into protoporphyrin IX in the presence of phosphate buffer solution.

[0071] To further illustrate that the tripod can stabilize gadolinium-protoporphyrin IX, Figure 7 the mass spectrum of the sample after adding phosphate buffer solution for three days was given, and it was found that the m / z peak corresponding to the tripod-gadolinium-protoporphyrin IX still had a very strong signal.

[0072] Example 3

[0073] The tripod-gadolinium-protoporphyrin IX obtained in Example 2 was deoxygenated in the methanol / phosphate buffer solution system. Figure 8 The luminescence spectra before and after deoxygenation were given. It was found that the peak corresponding to fluorescence remained basically unchanged, and the peak near 710 nm corresponding to phosphorescence showed a huge enhancement. This also indicated that this peak was phosphorescence emission because phosphorescence emission is extremely sensitive to oxygen. Based on this, a ratio sensor can be established to analyze the oxygen concentration.

[0074] Example 4

[0075] Using protoporphyrin IX and gadolinium chloride as raw materials, by the solvothermal method, with imidazole as the thermal solvent, the molar ratio of imidazole to protoporphyrin IX was 4100:1, the molar ratio of protoporphyrin IX to gadolinium chloride was 1:9, the temperature of the solvothermal reaction was 130 °C, and the time of the solvothermal reaction was 13 hours. Gadolinium-protoporphyrin IX was synthesized. After the reaction ended, it was allowed to cool naturally to room temperature to obtain a crystalline solid containing gadolinium-protoporphyrin IX.

[0076] The obtained crystalline solid was dissolved in methanol, which would contain gadolinium-protoporphyrin IX, imidazole, Gd 3+ , Cl - and other components. It was dialyzed and purified 4 times with methanol as the solvent to remove components with relatively small molecular weights such as imidazole, Gd 3+ , Cl - and other components.

[0077] The dialyzed and purified gadolinium-protoporphyrin IX was mixed with the tripod methanol solution and stirred for 12 h to obtain the tripod-gadolinium-protoporphyrin IX.

[0078] Example 5

[0079] Using protoporphyrin IX and gadolinium chloride as raw materials, a solvothermal method was adopted with imidazole as the thermal solvent. The molar ratio of imidazole to protoporphyrin IX was 4200:1, and the molar ratio of protoporphyrin IX to gadolinium chloride was 1:11. The temperature of solvothermal reaction was 120 °C, and the time was 14 hours. Gadolinium-protoporphyrin IX was synthesized. After the reaction ended, it was allowed to cool naturally to room temperature to obtain a crystalline solid containing gadolinium-protoporphyrin IX.

[0080] The obtained crystalline solid was dissolved in methanol, which would contain gadolinium-protoporphyrin IX, imidazole, Gd 3+ , Cl - and other components. It was dialyzed and purified 3 times with methanol as the solvent to remove components with relatively small molecular weights such as imidazole, Gd 3+ , Cl - and other components.

[0081] The dialyzed and purified gadolinium-protoporphyrin IX was mixed with a methanol solution of tripod and stirred for 13 h to obtain tripod-gadolinium-protoporphyrin IX.

[0082] Example 6

[0083] Using protoporphyrin IX and gadolinium chloride as raw materials, a solvothermal method was adopted with imidazole as the thermal solvent. The molar ratio of imidazole to protoporphyrin IX was 4000:1, and the molar ratio of protoporphyrin IX to gadolinium chloride was 1:10. The temperature of solvothermal reaction was 120 °C, and the time was 14 hours. Gadolinium-protoporphyrin IX was synthesized. After the reaction ended, it was allowed to cool naturally to room temperature to obtain a crystalline solid containing gadolinium-protoporphyrin IX.

[0084] The obtained crystalline solid was dissolved in methanol, which would contain gadolinium-protoporphyrin IX, imidazole, Gd 3+ , Cl - and other components. It was dialyzed and purified 3 times with methanol as the solvent to remove components with relatively small molecular weights such as imidazole, Gd 3+ , Cl - and other components.

[0085] The dialyzed and purified gadolinium-protoporphyrin IX was mixed with a methanol solution of tripod and stirred for 14 h to obtain tripod-gadolinium-protoporphyrin IX.

[0086] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for preparing tripod-gadolinium-protoporphyrin IX, characterized in that: The following steps are involved: The organic solvent solution containing gadolinium-protoporphyrin IX is mixed with the organic solvent solution containing the tripod molecule and stirred at room temperature; The structure of the gadolinium-protoporphyrin IX is shown in formula (I): Formula (I); The structure of the tripod-gadolinium-protoporphyrin IX is shown in formula (II): Formula (II); The preparation method of gadolinium-protoporphyrin IX comprises the following steps: Protoporphyrin IX and gadolinium salt are used as raw materials, imidazole is used as a hot solvent, a solvothermal method is used for reaction, and after the reaction is completed, the reaction is cooled to obtain a crystalline solid containing gadolinium-protoporphyrin IX; dissolving the crystalline solid containing gadolinium-protoporphyrin IX in an organic solvent and performing dialyzing purification using the organic solvent to obtain gadolinium-protoporphyrin IX; The gadolinium salt is gadolinium chloride or gadolinium nitrate; The molar ratio of protoporphyrin IX and gadolinium salt is 1:(9-11); The temperature of the solvothermal reaction is 120~140℃ and the time is 6~8 h; The experimental mass spectrum of gadolinium-protoporphyrin IX is highly consistent with its theoretical mass spectrum; The Tripod-Gd-Protoporphyrin IX experimental mass spectrum is highly consistent with its theoretical mass spectrum; The tripod molecule is sodium (cyclopentadienyl) tris (dimethylphosphite) cobalt (I).

2. The preparation method according to claim 1, characterized in that: The concentration of the organic solvent solution containing gadolinium-protoporphyrin IX is 1-3 mM, the concentration of the organic solvent solution containing the tripod molecule is 2-4 mM, and the volume ratio of the organic solvent solution containing gadolinium-protoporphyrin IX to the organic solvent solution containing the tripod molecule is 1:(0.9-1.1); The organic solvent is methanol or ethanol; The stirring time is 12~14 h.

3. The preparation method according to claim 1, characterized in that: The organic solvent is methanol or ethanol; The number of dialysis purifications is 3 to 5 times, and each time lasts 2 to 3 hours.

4. Use of tripod-gadolinium-protoporphyrin IX prepared by the preparation method according to any one of claims 1 to 3 in the preparation of oxygen sensor materials.

5. The use according to claim 4, characterized in that: Application in phosphate systems.

6. A method for measuring oxygen by ratio method, characterized in that: The method uses the tripod-gadolinium-protoporphyrin IX obtained by the preparation method according to any one of claims 1 to 3 as an oxygen concentration detection sensor, and comprises the following steps: Tripod-gadolinium-protoporphyrin IX is placed in a phosphate buffer solution, and a nitrogen gas flow is passed above the liquid surface of the solution. The luminescence spectrum before and after the nitrogen flow is measured; phosphorescence is used as the oxygen sensing signal and fluorescence is used as the reference signal, and the oxygen concentration is detected based on the phosphorescence-fluorescence intensity ratio.

7. The method according to claim 6, characterized in that The nitrogen flow time is 3 to 5 minutes; Tripod-gadolinium-protoporphyrin IX was first dissolved in an organic solvent and then placed in a phosphate buffer solution; The organic solvent is methanol or ethanol; The emission wavelength of fluorescence is 610~640nm, and the emission wavelength of phosphorescence is 700~740nm.

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