Tripod-gadolinium-protoporphyrin IX as well as preparation method and application thereof

Abstract

The invention discloses tripod-gadolinium-protoporphyrin IX as well as a preparation method and application thereof, and belongs to the field of inorganic chemistry. The preparation method comprises the following steps: firstly, preparing gadolinium-protoporphyrin IX by utilizing coordination of protoporphyrin IX and gadolinium, and finding that the gadolinium-protoporphyrin IX is also unstable in a water phase; in order to improve the stability of gadolinium-protoporphyrin IX in a water phase, the invention provides a method for coordinating gadolinium in gadolinium-protoporphyrin IX by using a tripod molecule, the tripod-gadolinium-protoporphyrin IX stable in the water phase is obtained, and the tripod molecule is sodium (cyclopentadienyl) tris (dimethyl phosphorous acid acyloxy) cobalt (I). The tripod-gadolinium-protoporphyrin IX is further used for carrying out ratio sensing determination on the dissolved oxygen, and the tripod-gadolinium-protoporphyrin IX has better response sensitivity, response time and repeatability as a sensor.

Description

Technical Field

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

[0002] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention, and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art.

[0003] Metalloporphyrins are widely used in biomedicine, photocatalysis, analytical chemistry and other fields. Among them, metalloporphyrins 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 long triplet lifetimes and phosphorescence emission quantum yields, but their emission peaks are located around 650 nm, which has not yet reached the optical window of tissues. Lanthanide metalloporphyrins, such as gadolinium porphyrin and lutetium porphyrin, have also been reported to have phosphorescence emission. Compared with platinum metalloporphyrins, the phosphorescence emission wavelength of gadolinium porphyrin exceeds 700 nm. In addition, lanthanide metals have advantages over platinum metals in that they are easier to obtain and cheaper. For example, the price of gadolinium chloride is about 1 / 10 of that of palladium chloride.

[0004] However, the structure of gadolinium porphyrin is unstable in phosphate buffer solution (pH=7.2). This may be because gadolinium usually has 7-8 coordination sites, and only 4 sites are coordinated by the 4 nitrogen atoms of porphyrin. The remaining sites may be occupied by other groups in phosphate buffer solution, resulting in the destruction of the symmetry of gadolinium porphyrin and even the dissociation of gadolinium ions and 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 and its preparation method and application. First, protoporphyrin IX is coordinated with gadolinium to obtain gadolinium-protoporphyrin IX, and it is 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 using a tripod molecule, and obtains a tripod-gadolinium-protoporphyrin IX that is stable in the aqueous phase, and further uses the tripod-gadolinium-protoporphyrin IX to perform ratio sensing measurement of dissolved oxygen.

[0006] In order to achieve the above object, the technical solution of the present invention is: In a first aspect, the present invention provides a tripod-gadolinium-protoporphyrin IX, wherein the structure of the tripod-gadolinium-protoporphyrin IX is as shown in formula (II); Formula (II).

[0007] The tripod-gadolinium-protoporphyrin IX has a stable structure in a phosphate buffer solution.

[0008] The study found that the structure of gadolinium-protoporphyrin IX is unstable in phosphate buffer solution, and its luminescence and absorption spectra will change with the addition of phosphate buffer solution, gradually becoming the characteristics of protoporphyrin IX. The reason for the breakage is that the oxygen atoms in the phosphate group in the phosphate system will coordinate with the gadolinium in gadolinium-protoporphyrin IX to form a gadolinium-oxygen bond, which will cause the gadolinium-nitrogen bond between gadolinium and protoporphyrin IX to break, resulting in the dissociation of the metal in the metal complex, and the oxygen atoms in the tripod molecule will be pre-coordinated with the gadolinium in gadolinium-protoporphyrin IX, and the tripod molecule will not break the gadolinium-nitrogen bond, and finally form a tripod-gadolinium-protoporphyrin IX molecule. After entering the system containing phosphate, this molecule will no longer coordinate with exogenous substances in the system, so the stability of the structure can be guaranteed.

[0009] 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: 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).

[0010] In one or more embodiments, the tripod molecule is sodium (cyclopentadienyl) tris (dimethylphosphite) cobalt (I).

[0011] 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).

[0012] In one or more embodiments, the organic solvent is methanol or ethanol.

[0013] In one or more embodiments, the stirring time is 12 to 14 h.

[0014] In one or more embodiments, the method for preparing 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; The crystalline solid containing gadolinium-protoporphyrin IX is dissolved in an organic solvent and dialyzed and purified using the organic solvent to obtain gadolinium-protoporphyrin IX.

[0015] Protoporphyrin IX is a widely used, relatively low-priced porphyrin with a certain degree of water solubility.

[0016] In one or more embodiments, the gadolinium salt is gadolinium chloride or gadolinium nitrate.

[0017] In one or more embodiments, the hot solvent used in the solvothermal reaction is imidazole. The amount of the hot solvent used is not particularly limited, as long as it is sufficient to allow the reaction to proceed fully. In an embodiment of the present invention, the molar ratio of imidazole to protoporphyrin IX is (3000-5000):1, preferably (3500-4500):1.

[0018] In one or more embodiments, the molar ratio of protoporphyrin IX to gadolinium salt is 1:(9-11).

[0019] In one or more embodiments, the temperature of the solvothermal reaction is 120-140°C, and the time is 6-9 hours, preferably 6-8 hours. A temperature exceeding 140°C will destroy the structure of the porphyrin. For example, when the temperature exceeds 200°C, some side chains (ether or carboxyl) of the porphyrin may be destroyed, resulting in the failure to detect the gadolinium porphyrin product in the mass spectrometry; if the time is too short, it is not conducive to the coordination of the gadolinium ion and the porphyrin, resulting in incomplete coordination and too low a yield of the metal porphyrin.

[0020] In one or more embodiments, the organic solvent is methanol or ethanol.

[0021] In one or more embodiments, the dialysis purification is performed 3 to 5 times, each time lasting 2 to 3 hours.

[0022] In a third aspect, the present invention provides use 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 preparing oxygen sensor materials.

[0023] Preferably, it is used in a phosphate system.

[0024] In a fourth aspect, a method for measuring oxygen using a ratio method is provided, wherein the method uses the tripod-gadolinium-protoporphyrin IX described in the first aspect 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.

[0025] In one or more embodiments, the nitrogen gas flow time is 3 to 5 minutes. When nitrogen gas is passed through the methanol / phosphate buffer solution system of tripod-gadolinium-protoporphyrin IX, it is found that the fluorescence of the system remains unchanged, while the phosphorescence is greatly enhanced within 3 minutes, and after the nitrogen gas flow is stopped, the phosphorescence will drop rapidly, and after the nitrogen gas flow is restarted, the phosphorescence can be restored again.

[0026] Preferably, the wavelength of the excitation light source is 350-450 nm, preferably 405 nm.

[0027] 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.

[0028] 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 to achieve real-time detection of oxygen concentration.

[0029] In one or more embodiments, Tripod-Gd-Protoporphyrin IX is first dissolved in an organic solvent and then placed in a phosphate buffer solution.

[0030] 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).

[0031] Preferably, the organic solvent is methanol or ethanol.

[0032] Preferably, the concentration of the organic solvent solution containing tripod-gadolinium-protoporphyrin IX is 40-250 μM.

[0033] Preferably, the concentration of the phosphate buffer solution is 0.01-0.02M.

[0034] One or some of the above technical solutions have the following advantages or beneficial effects: (1) The tripod-gadolinium-protoporphyrin IX provided by the present invention has a stable structure in the presence of a phosphate buffer solution. In the presence of a phosphate buffer solution, the fluorescence spectrum of gadolinium-protoporphyrin IX will rapidly change to the fluorescence characteristics of protoporphyrin IX within a few hours, that is, strong fluorescence, and the ultraviolet-visible absorption spectrum will also completely change to the absorption characteristics of protoporphyrin IX after a few days, that is, the Soret band (350-450 nm) absorption becomes broader, and the number of Q band (450-700 nm) absorption peaks increases. The molecular tripod-gadolinium-protoporphyrin IX of the coordination tripod has a stable structure in the presence of a phosphate buffer solution, which is specifically manifested as: no observable change in fluorescence within 24 hours, the ultraviolet-visible absorption spectrum after 6 days still reflects the absorption characteristics of metal porphyrin, and the mass spectrum after 3 days shows that the peak position and isotope peak shape of m / z are still consistent with those of gadolinium-protoporphyrin IX.

[0035] (2) The tripod-gadolinium-protoporphyrin IX molecule proposed in the present invention can be used to detect oxygen in the aqueous phase. When nitrogen was passed through the methanol / phosphate buffer solution system of tripod-gadolinium-protoporphyrin IX, it was found that the fluorescence of the system remained unchanged, while the phosphorescence showed a huge enhancement within 3 minutes. After the nitrogen was stopped, the phosphorescence dropped rapidly, and after the nitrogen was passed again, the phosphorescence could be restored. It has good response sensitivity, response time and repeatability. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0037] Figure 1 The mass spectrum and theoretical mass spectrum of gadolinium-protoporphyrin IX prepared in Example 1 of the present invention; wherein (a) is the mass spectrum, and (b) is the theoretical mass spectrum; Figure 2 The luminescence spectra after adding phosphate buffer solution in Example 1 of the present invention; wherein (a) is the luminescence spectra of gadolinium-protoporphyrin IX methanol solution at different times after adding phosphate buffer solution, and (b) is the luminescence spectrum of protoporphyrin IX in methanol / phosphate buffer solution; Figure 3 The UV-visible absorption spectra of gadolinium-protoporphyrin IX in different solutions in Example 1 of the present invention are shown in Figures 1 and 2; wherein (a) is the UV-visible absorption spectrum of gadolinium-protoporphyrin IX in a methanol solution, (b) is the UV-visible absorption spectrum of gadolinium-protoporphyrin IX in a methanol solution after a phosphate buffer solution is added thereto for 3 days, and (c) is the UV-visible absorption spectrum of protoporphyrin IX in a methanol / phosphate buffer solution. Figure 4The 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; Figure 5 The luminescence spectra at different times after adding phosphate buffer solution to the methanol solution of tripod-gadolinium-protoporphyrin IX in Example 2 of the present invention; Figure 6 The UV-visible absorption spectra of tripod-gadolinium-protoporphyrin IX in Example 2 of the present invention in different solutions; wherein (a) is the UV-visible absorption spectrum of tripod-gadolinium-protoporphyrin IX in a methanol solution, and (b) is the UV-visible absorption spectrum of tripod-gadolinium-protoporphyrin IX in a methanol solution after adding a phosphate buffer solution for 6 days; Figure 7 This is the mass spectrum of the tripod-gadolinium-protoporphyrin IX methanol solution in Example 2 of the present invention after phosphate buffer solution was added for 3 days; Figure 8 This is the luminescence spectrum of the tripod-gadolinium-protoporphyrin IX in Example 3 of the present invention before and after nitrogen gas was passed after being stored in a methanol / phosphate buffer solution for 5 hours. DETAILED DESCRIPTION

[0038] It should be noted that PpIX is protoporphyrin IX; Gd-PpIX is gadolinium-protoporphyrin IX; Gd-PpIX-L OMe It is a tripod-gadolinium-protoporphyrin IX.

[0039] Platinum and palladium porphyrins are the most commonly used phosphorescent metal porphyrins. Compared with platinum metal porphyrins, the phosphorescent emission wavelength of gadolinium porphyrin exceeds 700 nm. In addition, lanthanide metals have advantages over platinum metals in terms of easier availability and lower price. However, gadolinium porphyrin is structurally unstable in phosphate buffer solution (pH=7.2).

[0040] In order to solve the above problems, the design idea of ​​the present invention is: first, gadolinium-protoporphyrin IX is synthesized using gadolinium salt and protoporphyrin IX, and the synthesized gadolinium-protoporphyrin IX is characterized by mass spectrometry. It is found through experiments that gadolinium-protoporphyrin IX can exist stably in methanol, but when phosphate buffer solution is added to the solution, the luminescence spectrum will gradually change to the fluorescence characteristics of protoporphyrin IX, and the measurement of ultraviolet-visible absorption spectrum also confirms that phosphate will destroy the structure of gadolinium-protoporphyrin IX. The present invention uses a tripod ligand molecule to pre-coordinate gadolinium-protoporphyrin IX, so that the gadolinium in gadolinium-protoporphyrin IX will no longer be coordinated when phosphate exists. The synthesized tripod-gadolinium-protoporphyrin IX is characterized by mass spectrometry. The luminescence spectrum measurement finds that the luminescence characteristics of tripod-gadolinium-protoporphyrin IX in methanol / phosphate buffer solution are almost unchanged within 24 hours. The ultraviolet-visible absorption spectrum and mass spectrum also confirm that tripod-gadolinium-protoporphyrin IX can stably exist in a system containing a phosphate buffer solution. Finally, the tripod-gadolinium-protoporphyrin IX is used to perform a preliminary analysis of different oxygen concentrations.

[0041] The implementation method is as follows: (1) using protoporphyrin IX and a gadolinium source as raw materials and imidazole as a solvent, a solvothermal method is used to introduce gadolinium ions into the porphyrin ring, and after cooling, a crystalline solid containing gadolinium-protoporphyrin IX is obtained; (2) the obtained gadolinium-protoporphyrin IX is dissolved in methanol and dialyzed and purified using methanol as a solvent to remove excess impurities such as the gadolinium source and imidazole; (3) the purified product is mixed with a solution of a tripod ligand (methanol as a solvent) in a 1:1 ratio in a certain proportion, and stirred for a certain period of time to obtain tripod-gadolinium-protoporphyrin IX.

[0042] 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.

[0043] Example 1 Protoporphyrin IX and gadolinium chloride are used as raw materials, and a solvothermal method is adopted. Imidazole is used as a thermal solvent. The molar ratio of imidazole to protoporphyrin IX is 4000:1, the molar ratio of protoporphyrin IX to gadolinium chloride is 1:10, the solvothermal temperature is 140°C, and the solvothermal time is 8 hours. Gadolinium-protoporphyrin IX is synthesized. After the reaction is completed, it is 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); Formula (I).

[0044] The crystalline solid obtained by dissolving in methanol contains gadolinium-protoporphyrin IX, imidazole, Gd 3+ , Cl - The components were dialyzed and purified five times using methanol as solvent to separate the imidazole and Gd 3+ , Cl- The components were removed and characterized by mass spectrometry. Figure 1 As shown, the measured experimental mass spectrum of gadolinium-protoporphyrin IX is highly consistent with its theoretical mass spectrum, indicating that gadolinium-protoporphyrin IX was successfully synthesized.

[0045] The dialyzed purified gadolinium-protoporphyrin IX was diluted to a concentration of 250 μM and mixed with a 0.01 M phosphate buffer solution at a volume ratio of 1:1.

[0046] like Figure 2 As shown in (a), the luminescence spectrum of gadolinium-protoporphyrin IX methanol solution changes significantly at different times after adding phosphate buffer solution. Figure 2 (b) in the figure is the luminescence spectrum of protoporphyrin IX in methanol / phosphate buffer solution. By comparison, it is found that after a period of time, the luminescence spectrum of gadolinium-protoporphyrin IX changes into the luminescence characteristics of protoporphyrin IX.

[0047] like Figure 3 As shown in the figure, the UV-visible absorption spectrum of gadolinium-protoporphyrin IX in methanol solution is completely different from that of protoporphyrin IX, in which the Soret band (350-450 nm) is narrower and the number of Q band (450-700 nm) peaks is reduced to 2. However, 3 days after the addition of phosphate buffer solution, the characteristics of the Soret band and Q band are consistent with those of protoporphyrin IX.

[0048] Example 2 The gadolinium-protoporphyrin IX obtained in Example 1 was mixed with a solution of a tripod ligand (methanol as a solvent) in a certain ratio of 1:1, and stirred for a certain period of time to obtain tripod-gadolinium-protoporphyrin IX.

[0049] like Figure 4 As shown, the measured experimental mass spectrum of tripod-gadolinium-protoporphyrin IX is highly consistent with its theoretical mass spectrum, indicating that tripod-gadolinium-protoporphyrin IX was successfully synthesized.

[0050] Phosphate buffer solution (0.01 M) was added to the methanol solution of tripod-gadolinium-protoporphyrin IX (40 μM), and the changes in the luminescence spectrum over time were detected, e.g. Figure 5 As shown, the luminescence spectrum did not show obvious changes within 24 h, which preliminarily indicated that the tripod could stabilize Gd-protoporphyrin IX.

[0051] The UV-visible absorption spectra of Tripod-Gd-Protoporphyrin IX after storage in methanol / phosphate buffer solution for several days were also measured. Figure 6 As shown, it was found that the UV-visible absorption spectrum of tripod-Gd-protoporphyrin IX after storage for 6 days was completely consistent with that of tripod-Gd-protoporphyrin IX in methanol, which confirmed that tripod-Gd-protoporphyrin IX no longer converted into protoporphyrin IX in the presence of phosphate buffer solution.

[0052] To further demonstrate that the tripod can stabilize Gd-protoporphyrin IX, Figure 7 The mass spectrum of the sample three days after the addition of phosphate buffer solution is shown, and it is found that the m / z peak corresponding to tripod-gadolinium-protoporphyrin IX still has a strong signal.

[0053] Example 3 The tripod-gadolinium-protoporphyrin IX obtained in Example 2 was subjected to a deoxygenation treatment in a methanol / phosphate buffer solution system. Figure 8 The luminescence spectra before and after deoxygenation are given, and it is found that the peak corresponding to fluorescence remains basically unchanged, and the peak corresponding to phosphorescence at around 710 nm shows a huge enhancement, which also shows that this peak is phosphorescence emission, because phosphorescence emission is extremely sensitive to oxygen. Based on this, a ratio sensor can be established to analyze the oxygen concentration.

[0054] Example 4 Protoporphyrin IX and gadolinium chloride are used as raw materials, a solvothermal method is adopted, imidazole is used as a thermal solvent, the molar ratio of imidazole to protoporphyrin IX is 4100:1, the molar ratio of protoporphyrin IX to gadolinium chloride is 1:9, the solvothermal temperature is 130 ° C, the solvothermal time is 13 hours, gadolinium-protoporphyrin IX is synthesized, and after the reaction is completed, it is allowed to cool naturally to room temperature to obtain a crystalline solid containing gadolinium-protoporphyrin IX.

[0055] The crystalline solid obtained by dissolving in methanol contains gadolinium-protoporphyrin IX, imidazole, Gd 3+ , Cl - The components were dialyzed and purified four times using methanol as solvent to separate the imidazole and Gd 3+ , Cl - And other ingredients removed.

[0056] The dialyzed purified gadolinium-protoporphyrin IX was mixed with the tripod methanol solution and stirred for 12 h to obtain tripod-gadolinium-protoporphyrin IX.

[0057] Example 5 Protoporphyrin IX and gadolinium chloride are used as raw materials, a solvothermal method is adopted, imidazole is used as a thermal solvent, the molar ratio of imidazole to protoporphyrin IX is 4200:1, the molar ratio of protoporphyrin IX to gadolinium chloride is 1:11, the solvothermal temperature is 120 ° C, the solvothermal time is 14 hours, gadolinium-protoporphyrin IX is synthesized, and after the reaction is completed, it is allowed to cool naturally to room temperature to obtain a crystalline solid containing gadolinium-protoporphyrin IX.

[0058] The crystalline solid obtained by dissolving in methanol contains gadolinium-protoporphyrin IX, imidazole, Gd 3+ , Cl -The components were dialyzed and purified three times using methanol as solvent to separate the imidazole and Gd 3+ , Cl - And other ingredients removed.

[0059] The dialyzed purified gadolinium-protoporphyrin IX was mixed with the tripod methanol solution and stirred for 13 h to obtain tripod-gadolinium-protoporphyrin IX.

[0060] Example 6 Protoporphyrin IX and gadolinium chloride are used as raw materials, a solvothermal method is adopted, imidazole is used as a thermal solvent, the molar ratio of imidazole to protoporphyrin IX is 4000:1, the molar ratio of protoporphyrin IX to gadolinium chloride is 1:10, the solvothermal temperature is 120 ° C, the solvothermal time is 14 hours, gadolinium-protoporphyrin IX is synthesized, and after the reaction is completed, it is allowed to cool naturally to room temperature to obtain a crystalline solid containing gadolinium-protoporphyrin IX.

[0061] The crystalline solid obtained by dissolving in methanol contains gadolinium-protoporphyrin IX, imidazole, Gd 3+ , Cl - The components were dialyzed and purified three times using methanol as solvent to separate the imidazole and Gd 3+ , Cl - And other ingredients removed.

[0062] The dialyzed purified gadolinium-protoporphyrin IX was mixed with the tripod methanol solution and stirred for 14 h to obtain tripod-gadolinium-protoporphyrin IX.

[0063] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A tripod-gadolinium-protoporphyrin IX, characterized in that: The structure of the tripod-gadolinium-protoporphyrin IX is shown in formula (II): Formula (II).

2. A method for preparing the tripod-gadolinium-protoporphyrin IX according to claim 1, 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).

3. The method according to claim 2, characterized in that The tripod molecule is sodium (cyclopentadienyl) tris (dimethylphosphite) cobalt (I).

4. The method according to claim 2, 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.

5. The method according to claim 2, characterized in that: 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; The crystalline solid containing gadolinium-protoporphyrin IX is dissolved in an organic solvent and dialyzed and purified using the organic solvent to obtain gadolinium-protoporphyrin IX.

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

7. Use of the tripod-gadolinium-protoporphyrin IX according to claim 1 or the tripod-gadolinium-protoporphyrin IX prepared by the method according to any one of claims 2 to 6 in preparing oxygen sensor materials.

8. The use according to claim 7, characterized in that: Application in phosphate systems.

9. A method for measuring oxygen by ratio method, characterized in that: The method uses the tripod-gadolinium-protoporphyrin IX described in claim 1 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.

10. The method according to claim 9, 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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