Preparation method and application of binuclear rare earth cluster crystalline material

Abstract

The invention discloses a preparation method and application of a binuclear rare earth cluster crystalline material, belonging to the field of rare earth metal material synthesis. The invention prepares a binuclear rare earth cluster crystalline material by a volatilization method. The binuclear rare earth cluster crystalline material is constructed by a rare earth (III) element, a ligand 2,3,4,5,6-pentafluorobenzoic acid (HPFBA) and an auxiliary ligand 1,10-phenanthroline (phen), and has a chemical formula of RE2(PFBA)6(phen)2(H2O)2, wherein RE is a positive trivalent rare earth ion Eu(III) or Tb(III), and PFBA is a deprotonated 2,3,4,5,6-pentafluorobenzoic acid. The binuclear rare earth cluster crystalline material has excellent fluorescence properties and can selectively identify specific Cr 3+ This results in the quenching of its fluorescence signal and can be used as a fluorescent probe for Cr 3+ and as a fluorescent probe to detect Cr 3+ It has the characteristics of low detection limit, strong anti-interference and fast response time. It can also be applied to Cr in water environment and human serum and urine. 3+ The preparation method of the present invention is simple and easy to operate, does not require expensive precision instruments and equipment, and is suitable for popularization and application.

Description

Technical Field

[0001] The invention belongs to the field of rare earth metal material synthesis, and particularly relates to a preparation method of a binuclear rare earth cluster crystalline material and application thereof. Background Art

[0002] Chromium plays an important role in the human body, and is closely related to insulin. It plays an important role in diabetic patients, and is a very beneficial trace element for the human body. When chromium is deficient, it is easy to show glucose metabolism disorders, which in turn leads to diabetes. But at the same time, chromium is a highly toxic heavy metal that can easily enter human cells and cause damage to organs such as the liver and kidneys. If chromium accumulates in the human body, it may cause cancer. For the environment, excessive chromium ions (Cr 3+ ) is lethal to aquatic organisms, and chromium ions that enter the soil will accumulate in the plant body as the plant metabolizes, and then enter the human body, causing harm to human health. 3+ ) is mainly derived from the process of mineral smelting. Therefore, the Cr in the wastewater of each factory is 3+ It is of great significance to conduct rapid and sensitive detection of Cr content. Therefore, it is necessary to develop an efficient, accurate, simple and fast method to detect Cr 3+ method.

[0003] Currently, the detection of Cr 3+ The main methods include atomic absorption spectroscopy, oscillographic polarography, direct current method, etc., but these methods are costly, cumbersome, and low in sensitivity, and cannot perform simple and rapid analysis in real time. In recent years, fluorescent probes have been increasingly used in various fields due to their advantages such as strong selectivity, high sensitivity, fast response time, low cost, and convenience.

[0004] Rare earth complexes have diverse coordination geometric structures, unique magnetism and stability, and unique optical properties generated by the antenna effect, including large Stokes shift, stable emission band and long luminescence lifetime, making them ideal luminescent sensing materials. In rare earth complex fluorescent probes, organic ligands can sensitize rare earth ions through the "antenna effect" to emit strong characteristic fluorescence. This high-intensity characteristic fluorescence can interact with some non-fluorescent metal cations to cause quenching of the fluorescence of the rare earth complex. With the help of this change in the luminescence properties of the complex, it can be used to identify and detect the presence of metal cations.

[0005] Rare earth complex fluorescent probes have unique optical properties, with the characteristics of small sample usage, fast analysis speed, high sensitivity, and low detection limit. 3+ Specific detection of Cr 3+In order to detect the rare earth metals, it is also necessary to select suitable rare earth metals and organic ligands to construct rare earth metal complex materials that can serve as detection targets. Summary of the invention

[0006] In view of the problems existing in the above-mentioned prior art, the object of the present invention is to provide a preparation method and application of a binuclear rare earth cluster crystalline material. The binuclear rare earth cluster crystalline material has excellent fluorescence properties and can be used as a fluorescent probe for Cr 3+ It has the characteristics of low detection limit, strong anti-interference and fast response time, and can be applied to the detection of trace Cr in water environment, human serum and urine. 3+ Qualitative detection.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] The first aspect of the present invention provides a binuclear rare earth cluster crystalline material, which is constructed from a rare earth (III) element, a ligand 2,3,4,5,6-pentafluorobenzoic acid and an auxiliary ligand 1,10-phenanthroline, and has a chemical formula of RE2(PFBA)6(phen)2(H2O)2, wherein the RE is a positive trivalent rare earth ion Eu(III) or Tb(III), the PFBA is a deprotonated 2,3,4,5,6-pentafluorobenzoic acid, and the phen is 1,10-phenanthroline.

[0009] Preferably, the binuclear rare earth cluster crystalline material crystallizes in the monoclinic system, the space group is P-1, and the unit cell parameters are: α=63.938~84.122°, β=65.040~85.549°, γ=59.820~80.238°,

[0010] Preferably, the basic structural unit of the binuclear rare earth cluster crystalline material is a neutral structural unit composed of two crystallographically independent REs with the same coordination environment, six PFBAs, two phens, and two free water molecules, and in the basic structural unit, the two REs adopt an eight-coordination mode, three PFBA ligands and one phen ligand are chelated with one RE, wherein the six Os involved in the coordination come from the carboxyl oxygens in the three PFBA ligands, the two Ns come from the phen ligands, and the RE-O bond length is between The bond length of RE-N is between between.

[0011] The second aspect of the present invention provides a method for preparing the above binuclear rare earth cluster crystalline material, comprising the following steps:

[0012] S1, dissolving a rare earth soluble salt in a solvent to obtain a rare earth salt solution;

[0013] S2, adding deprotonated 2,3,4,5,6-pentafluorobenzoic acid to the rare earth salt solution obtained in step S1 and mixing evenly to obtain a mixed solution A;

[0014] S3, dissolving 1,10-phenanthroline in an organic solvent, and then adding the organic solvent to the mixed solution A obtained in step S2 and mixing the mixture to obtain a mixed solution B;

[0015] S4, sealing the mixed solution B obtained in step S3 with plastic wrap in a container, piercing holes, and evaporating the solvent to obtain a binuclear rare earth cluster crystalline material.

[0016] Preferably, in step S1, the rare earth soluble salt is any one of nitrate, chloride, acetate, sulfonate, oxalate and triflate of a rare earth metal.

[0017] Preferably, in step S1, the amount of the solvent used is 10 to 1000 times, more preferably 20 to 200 times, the amount of the rare earth soluble salt used by weight.

[0018] Preferably, in step S1, the solvent is water or an organic solvent, and the organic solvent is preferably one or a combination of two or more of dimethyl sulfoxide, N,N-dimethylformamide, tetrahydrofuran, methanol, acetonitrile, ethanol, acetone, acetylacetone, dichloromethane and chloroform.

[0019] Preferably, in step S2, the deprotonated 2,3,4,5,6-pentafluorobenzoic acid is obtained by adjusting the pH of 2,3,4,5,6-pentafluorobenzoic acid to 5.5-6.5 by adding alkali solution, and the alkali solution is one or a combination of two or more of sodium hydroxide, potassium hydroxide, triethylamine or ammonia water.

[0020] Preferably, in step S3, the amount of the organic solvent used is 200 to 1000 times, more preferably 30 to 800 times, by weight of the amount of 1,10-phenanthroline used.

[0021] Preferably, in step S3, the organic solvent is one or a combination of two or more of dimethyl sulfoxide, N,N-dimethylformamide, tetrahydrofuran, methanol, acetonitrile, ethanol, acetone, acetylacetone, dichloromethane and chloroform.

[0022] Preferably, in step S4, the environmental condition for the volatilization of the solvent in the mixed solution B is any one of normal air, nitrogen, oxygen and argon atmospheres, and is more preferably normal air atmosphere.

[0023] Preferably, in step S4, the mixed liquid evaporates for 1 to 90 days under normal atmospheric conditions.

[0024] Preferably, the molar ratio of the rare earth soluble salt, 2,3,4,5,6-pentafluorobenzoic acid and 1,10-phenanthroline is 1:3:1.

[0025] The third aspect of the present invention also provides the above binuclear rare earth cluster crystalline material as a fluorescent probe for application in Cr in actual environment. 3+ Detection, wherein the actual environment includes water environment and human serum, urine, etc.

[0026] The fourth aspect of the present invention also provides a test paper made of the above binuclear rare earth cluster crystalline material for Cr 3+ Qualitative detection.

[0027] The present invention has the following beneficial effects:

[0028] (1) In the present invention, pentafluorobenzoic acid is selected as the first ligand. On the one hand, for metal ions, the energy transfer process is considered to be an important quenching mechanism, that is, the ligand of the complex absorbs light, and then the electron is transferred from the ground state S0 to the excited singlet state S1. The life of the singlet state S1 is very short. After crossing to the lowest excited state T1, the energy is then transferred from the minimum excited triplet state T1 to the rare earth ion through energy transfer, and the ground state electron is transferred to the ground state rare earth ion, thereby emitting light. Since there is an oxygen in the carboxyl group of pentafluorobenzoic acid in the binuclear rare earth cluster crystalline material of the present invention that does not participate in coordination, the uncoordinated oxygen can react with Cr 3+ The effective binding hinders the energy transfer from the lowest excited triplet state T1 to the rare earth ion, resulting in the energy transfer from the ligand to Cr 3+ , resulting in fluorescence quenching; on the other hand, because there is no oscillating group on the pentafluorobenzoic acid ligand, the above energy transfer efficiency can be higher.

[0029] (2) In the present invention, pentafluorobenzoic acid is selected as the first ligand and 1,10-phenanthroline is selected as the auxiliary ligand, so that the structure of the binuclear rare earth cluster crystalline material finally prepared is more stable, and it can maintain excellent stability even when placed in a pH range of 2 to 13 and in different organic solvents.

[0030] (3) The present invention prepares a binuclear rare earth cluster crystalline material by a volatilization method. The binuclear rare earth cluster crystalline material has excellent fluorescence properties and can selectively identify specific Cr 3+ This leads to the quenching of its fluorescence signal and can be used as a fluorescent probe for Cr 3+ As a fluorescent probe to detect Cr 3+It has the characteristics of low detection limit, strong anti-interference and fast response time. As a fluorescent probe, it is also suitable for detecting Cr in actual environments such as water environment, human serum and urine. 3+ Qualitative detection.

[0031] (4) The binuclear rare earth cluster crystalline material prepared by the present invention can also be made into test paper for Cr 3+ Qualitative detection of the substance can be achieved, thus laying the foundation for the subsequent design of a portable fluorescent probe.

[0032] (5) The preparation method of the present invention is simple and easy to operate, does not require expensive precision instruments and equipment, and is suitable for promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0034] Figure 1 It is a Tb binuclear rare earth cluster crystalline material (1-Tb) and Cr 3+ Crystal structure diagram before binding;

[0035] Figure 2 It is a Tb binuclear rare earth cluster crystalline material (1-Tb) and Cr 3+ The crystal structure diagram after combination;

[0036] Figure 3 PXRD patterns of Tb binuclear rare earth cluster crystalline materials (1-Tb) in different pH and solvents.

[0037] Figure 4 The Tb binuclear rare earth cluster crystalline material (1-Tb) and 23 different substances (Ba 2+ , Ca 2+ 、Cd 2+ 、Co 3+ Cr 3+ NH4 + Mg 2+ , Mn 2+ , Pb 2+ 、Zn 2+ , Fe 3+ , K + 、C6H5COO - 、AlO3 3- 、SiO3 2- 、C7H7O3S - 、B4O7 2- 、C6H5O7 3-、(C6H5)4B - 、CH3COO - WO4 2- 、SO4 2- 、SO3 2- ) The fluorescence spectrum histogram after combination (excitation wavelength is 335nm, and the highest characteristic emission peak is 534nm);

[0038] Figure 5 The Tb binuclear rare earth cluster crystalline material is 3+ Detection limit spectrum (excitation wavelength is 335nm);

[0039] Figure 6 The Tb binuclear rare earth cluster crystalline material is 3+ Response time curve (excitation wavelength is 335nm);

[0040] Figure 7 Detection of Cr for Tb binuclear rare earth cluster crystalline material (1-Tb) 3+ Anti-interference result diagram (excitation wavelength is 335nm);

[0041] Figure 8 The Tb binuclear rare earth cluster crystalline material was used as a fluorescent probe to detect Cr in water environment, human serum and urine. 3+ Fluorescence spectrum of (excitation wavelength is 335nm);

[0042] Fig. 9 This is a photograph of a test paper made of Tb binuclear rare earth cluster crystalline material immersed in 23 different ions; DETAILED DESCRIPTION

[0043] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present invention. However, it should be clear to those skilled in the art that the present invention may be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present invention.

[0044] Example 1

[0045] Preparation of Tb binuclear rare earth cluster crystalline materials:

[0046] S1. Dissolve 7.1 mg of terbium nitrate hexahydrate in 2.0 mL of methanol to obtain a terbium nitrate salt solution;

[0047] S2, 10.0 mg of 2,3,4,5,6-pentafluorobenzoic acid was placed in a beaker, 1.0 mL of water was added, and the pH was adjusted to 6.0 with 0.1 M sodium hydroxide solution to obtain deprotonated 2,3,4,5,6-pentafluorobenzoic acid; the deprotonated 2,3,4,5,6-pentafluorobenzoic acid was slowly added dropwise to the rare earth salt solution obtained in step S1 and mixed evenly to obtain a mixed solution A;

[0048] S3, dissolving 2.8 mg of 1,10-phenanthroline in 2.0 mL of ethanol, and then adding the mixture to the mixed solution A obtained in step S2 and mixing evenly to obtain a mixed solution B;

[0049] S4. Place the obtained mixed solution B in a 10.0 mL small beaker, seal it with plastic wrap and pierce it, let it stand at room temperature, and evaporate it under normal atmospheric conditions for 28 days to obtain 3.8 mg of colorless block crystals, i.e., Tb binuclear rare earth cluster crystalline material Tb2(PFBA)6(phen)2(H2O)2, recorded as 1-Tb.

[0050] Example 2

[0051] It is basically the same as Example 1, except that: in this example, "7.1 mg of terbium nitrate hexahydrate" is replaced by "7.0 mg of europium nitrate hexahydrate" to obtain 3.5 mg of colorless block crystals, namely Eu binuclear rare earth cluster crystalline material Eu2(PFBA)6(phen)2(H2O)2, recorded as 1-Eu.

[0052] Example 3

[0053] It is basically the same as Example 1, except that: in this example, "terbium nitrate hexahydrate is dissolved in 2.0 mL of methanol" is replaced by "terbium chloride hexahydrate is dissolved in 7.0 mL of deionized water", and 3.6 mg of colorless block crystals are obtained, namely, Tb binuclear rare earth cluster crystalline material Tb2(PFBA)6(phen)2(H2O)2, recorded as 2-Tb.

[0054] Example 4

[0055] It is basically the same as Example 2, except that: in this example, "europium nitrate hexahydrate is dissolved in 2.0 mL of methanol, and 2.8 mg of 1,10-phenanthroline is dissolved in 2.0 mL of ethanol" is replaced by "europium chloride hexahydrate is dissolved in 0.5 mL of ethanol, and 2.8 mg of 1,10-phenanthroline is dissolved in 0.5 mL of methanol", and 3.4 mg of colorless block crystals are obtained, namely Tb binuclear rare earth cluster crystalline material Eu2(PFBA)6(phen)2(H2O)2, recorded as 2-Eu.

[0056] Example 5

[0057] The method is basically the same as Example 1, except that: in this embodiment, "terbium nitrate hexahydrate is dissolved in 2.0 mL of methanol, and the mixed solution B is volatilized for 28 days under normal atmospheric environment" is replaced by "terbium chloride hexahydrate is dissolved in 1.0 mL of acetone, and the mixed solution B is volatilized for 5 days under normal atmospheric environment", and 3.5 mg of colorless block crystals are obtained, namely, Tb binuclear rare earth cluster crystalline material Tb2(PFBA)6(phen)2(H2O)2, recorded as 3-Tb.

[0058] Example 6

[0059] It is basically the same as Example 2, except that: in this example, "europium nitrate hexahydrate is dissolved in 2.0 mL of methanol, and the mixed solution B is volatilized for 28 days under normal atmospheric environment" is replaced by "europium chloride hexahydrate is dissolved in 7.0 mL of deionized water, and the mixed solution B is volatilized for 60 days under nitrogen atmosphere", and 3.4 mg of colorless block crystals are obtained, namely Tb binuclear rare earth cluster crystalline material Eu2(PFBA)6(phen)2(H2O)2, recorded as 3-Eu.

[0060] (1) Crystal structure determination of binuclear rare earth cluster crystalline materials

[0061] The crystal structure of the binuclear rare earth cluster crystalline material prepared in Examples 1-3 was determined using a single crystal X-ray diffractometer.

[0062] Determination of crystal diffraction data and structure: The binuclear rare earth cluster crystalline materials prepared in the above Examples 1-3 are heterogeneous isomorphous structures, all crystallized in the monoclinic system, and the space group is P-1; wherein, the unit cell parameters of 1-Tb are: α=73.938(2)°, β=75.040(3)°, γ=69.820(2)°, Z=2;1-Eu unit cell parameters: α=74.122(6)°, β=75.549(5)°, γ=70.238(5)°, Z=2; unit cell parameters of 2-Tb: α=74.035(3)°, β=75.196(3)°, γ=69.948(3)°, Z = 2. It is inferred that the chemical formula of the binuclear rare earth cluster crystalline material prepared by the present invention is: [RE2(PFBA)6(phen)2(H2O)2], wherein RE is Eu(III) or Tb(III).

[0063] Here we take 1-Tb as an example to describe its structure in detail. 1-Tb is a rare earth complex with a binuclear structure. It crystallizes in triclinic form and has a P-1 space group. The structure of its crystal is shown in the figure below. Figure 1 As shown by Figure 1 The results show that the basic unit of the Tb binuclear rare earth cluster crystalline material is a neutral structural unit composed of two crystallographically independent Tb(Ⅲ) with the same coordination environment, six PFBA ligands, two phen and two free water molecules. In the basic structural unit, the two Tb(Ⅲ) adopt an eight-coordination mode, three PFBA ligands and one phen ligand are chelated with one Tb(Ⅲ), among which the six O involved in the coordination come from the carboxyl oxygen of the three PFBA ligands, and the two N come from the phen ligand. The bond length of Tb-O is between The bond length of Tb-N is between between.

[0064] (2) Stability test of Tb binuclear rare earth cluster crystalline materials

[0065] 1-Tb powder was soaked in aqueous solutions of different pH values ​​and six organic solvents (methanol, ethanol, acetonitrile, acetone, tetrahydrofuran, acetylacetone) for half an hour, then centrifuged and dried. PXRD tests were performed together with 1-Tb powder that had not been soaked in the solution after being placed for 1 day and 30 days. The test results are as follows: Figure 3 shown.

[0066] Depend on Figure 3 The results show that by comparing the PXRD test results with the crystal simulation peaks, it is found that the two are basically consistent, which shows that the rare earth binuclear cluster crystalline material prepared by the present invention has excellent stability.

[0067] (3) Study on the fluorescence properties of Tb binuclear rare earth cluster crystalline materials

[0068] 5.0 mg of 1-Tb powder was dissolved in 5 mL of DMF to obtain a 1-Tb DMF solution. 50 uL of the 1-Tb DMF solution was added to 4.9 mL of deionized water and divided into 24 portions. 50 uL of deionized water was added to one portion as a blank sample. 50 uL of Cr was added to one portion. 3+ Solution (1.0×10 -3 M) (solvent is deionized water), and finally add Cr 3+ Solution (1.0×10 -3 M) (solvent is deionized water) and 22 other substances with the same concentration and solvent (Ba 2+ , Ca 2+ 、Cd 2 + 、Co 3+ NH4+ Mg 2+ , Mn 2+ , Pb 2+ 、Zn 2+ , Fe 3+ , K + 、C6H5COO - 、AlO3 3- 、SiO3 2- 、C7H7O3S - 、B4O7 2- 、C6H5O7 3- 、(C6H5)4B - 、CH3COO - WO4 2- 、SO4 2- 、SO3 2- ), under the same conditions, the fluorescence performance test (excitation wavelength is 335nm), the test results are as follows Figure 4 shown.

[0069] Depend on Figure 4 The bar graph shows that the blank 1-Tb DMF solution has the maximum emission peak at 534nm (reference Figure 5 Spectrum), compared with adding other substances, adding Cr 3+ The DMF solution of 1-Tb showed obvious fluorescence quenching effect at 534nm. This indicates that the Tb binuclear rare earth cluster crystalline material (1-Tb) has a strong effect on Cr 3+ Has a significant fluorescence quenching effect. Figure 2 Since one of the carboxyl oxygen groups of pentafluorobenzoic acid in the Tb binuclear rare earth cluster crystalline material (1-Tb) is not involved in the coordination, the uncoordinated oxygen is bound to Cr 3+ The combination is carried out, so that the energy transfer from the lowest excited triplet state T1 to the rare earth ion is hindered, resulting in the energy transfer from the ligand to Cr 3+ , which causes fluorescence quenching. The above results confirm that the binuclear rare earth cluster crystalline material prepared by the present invention can recognize specific Cr 3+ This results in the quenching of its fluorescence signal.

[0070] Depend on Figure 5 The results show that binuclear rare earth cluster crystalline materials can be used as fluorescent probes for Cr 3+ The detection limit is as low as 5.2ppb, and the response time is extremely short. Figure 6 As shown in FIG. 1 , the maximum quenching efficiency (25%) can be achieved within 1 minute, further confirming that the binuclear rare earth cluster crystalline material prepared by the present invention can selectively recognize specific Cr 3+ The quenching of its fluorescence signal can be used as a trace amount of Cr 3+The fluorescent probe can be used for detection, and the detection can be completed in a short time (1min) and has low requirements for detection equipment.

[0071] (4) Anti-interference test

[0072] 5.0 mg of 1-Tb powder was added to 5.0 mL of DMF solution to dissolve the powder to obtain 1-Tb solution. 50.0 uL of 1-Tb solution was added to 4.9 mL of deionized water, and then 50.0 uL of Cr 3+ Solution (1.0×10 -3 M) (solvent is deionized water) and 50.0uL of 22 different interfering ions (Ba 2+ , Ca 2+ 、Cd 2+ 、Co 3+ NH4 + Mg 2+ , Mn 2+ , Pb 2+ 、Zn 2+ , Fe 3+ , K + 、C6H5COO - 、AlO3 3- 、SiO3 2- 、C7H7O3S - 、B4O7 2- 、C6H5O7 3- 、(C6H5)4B - 、CH3COO - WO4 2- 、SO4 2- 、SO3 2- ), the fluorescence performance test was carried out by fluorescence spectrometer with an excitation wavelength of 335nm, and the anti-interference results were obtained as follows Figure 7 shown.

[0073] Depend on Figure 7 The results show that the presence of different interfering ions has a significant effect on Cr 3+ The detection results were not significantly affected, that is, the Tb binuclear rare earth cluster crystalline material (1-Tb) prepared by the present invention had excellent anti-interference performance.

[0074] (5) Application of binuclear rare earth cluster crystalline materials as fluorescent probes in practical environments 3+ Detection

[0075] 1-Tb was used as a fluorescent probe to detect Cr in water environment, human serum and urine. 3+ Test: Take 50uL of 1-Tb solution and add it to 4.4mL of deionized water, then add 50uL of Cr 3+Solution (1.0×10 -3 M), add 500 μL of lake water, tap water, and human urine (50 times diluted with saline) respectively, take 50uL of 1-Tb solution and add it to 4.8mL of deionized water, then add 50uL of Cr 3+ Solution (1.0×10 -3 M), and then added 100 μL of human serum (diluted 100 times with normal saline), and the fluorescence performance was tested by fluorescence spectrometer with an excitation wavelength of 335 nm. The results are as follows Figure 8 shown.

[0076] Depend on Figure 8 The results show that 1-Tb contains trace amounts (1.0×10 -5 mol / L)Cr 3+ The fluorescence at 534nm was significantly quenched in water environments (lake water and tap water) and human serum and urine, indicating that the binuclear rare earth complex 1-Tb has a strong effect on Cr 3+ It has excellent fluorescence sensing effect and can be used as a fluorescent probe in the actual environment to detect Cr 3+ Qualitative detection.

[0077] (6) Using binuclear rare earth cluster crystalline materials to make test paper for Cr 3+ Detection

[0078] Cut the filter paper into appropriate size (1*1cm 2 ), soaked in 1-Tb (0.01M) DMF solution for 30 minutes, and then dried at 80°C for sensing applications. The above dried test paper was soaked in the above 23 different ion solutions, and a blank was used as a control. After drying, it was placed neatly and photographed under 365nm ultraviolet light. The obtained photos are shown in Figure 1. Fig. 9 shown.

[0079] Depend on Fig. 9 The results showed that except for immersion in Cr 3+ Except for the test paper in the solution, all the test papers immersed in other ion solutions emitted Tb 3+ The unique green luminescence indicates that the binuclear rare earth cluster crystalline material prepared by the present invention can be made into test paper for Cr 3+ Qualitative detection.

[0080] The present invention is not limited to the above-mentioned specific implementation modes. Various changes made by ordinary technicians in this field based on the above-mentioned concepts without creative work are all within the protection scope of the present invention.

Claims

1. Preparation of binuclear rare earth cluster crystalline materials for practical environment Cr 3+ The use of a fluorescent probe for detection, characterized in that The chemical formula of the binuclear rare earth cluster crystalline material is: RE2(PFBA)6(phen)2(H2O)2, wherein the RE is a positive trivalent rare earth ion Eu(III) or Tb(III), the PFBA is a deprotonated 2,3,4,5,6-pentafluorobenzoic acid, and the phen is 1,10-phenanthroline; The binuclear rare earth cluster crystalline material crystallizes in the monoclinic system, and the space group is P -1, unit cell parameters: a = 9.8707~11.8923Å, b = 11.1254~13.1462Å, c = 13.0734~15.0780Å, α =63.938~84.122°, β =65.040~85.549°, γ = 59.820~80.238°, V = 1047.52~2057.01Å 3 ; The basic structural unit of the binuclear rare earth cluster crystalline material is a neutral structural unit composed of two crystallographically independent REs with the same coordination environment, six PFBAs, two phens, and two free water molecules, and in the basic structural unit, the two REs adopt an eight-coordination mode, three PFBA ligands and one phen ligand are chelated with one RE, wherein the six Os involved in the coordination come from the carboxyl oxygens in the three PFBA ligands, and the two Ns come from the phen ligands, the RE-O bond length is between 2.339-2.729 Å, and the RE-N bond length is between 2.576-2.585 Å; The actual environment includes water environment and human serum and urine.

2. Binuclear rare earth cluster crystalline materials in the preparation of Cr 3+ Application in test paper for qualitative detection, characterized in that, The chemical formula of the binuclear rare earth cluster crystalline material is: RE2(PFBA)6(phen)2(H2O)2, wherein the RE is a positive trivalent rare earth ion Eu(III) or Tb(III), the PFBA is a deprotonated 2,3,4,5,6-pentafluorobenzoic acid, and the phen is 1,10-phenanthroline; The binuclear rare earth cluster crystalline material crystallizes in the monoclinic system, and the space group is P -1, unit cell parameters: a = 9.8707~11.8923Å, b = 11.1254~13.1462Å, c = 13.0734~15.0780Å, α =63.938~84.122°, β =65.040~85.549°, γ = 59.820~80.238°, V = 1047.52~2057.01Å 3 ; The basic structural unit of the binuclear rare earth cluster crystalline material is a neutral structural unit composed of two crystallographically independent REs with the same coordination environment, six PFBAs, two phens and two free water molecules. In the basic structural unit, the two REs adopt an eight-coordination mode, three PFBA ligands and one phen ligand are chelated with one RE, wherein the six Os involved in the coordination come from the carboxyl oxygens in the three PFBA ligands, and the two Ns come from the phen ligands. The bond length of RE-O is between 2.339-2.729 Å, and the bond length of RE-N is between 2.576-2.585 Å.

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