CN109627450B

CN109627450B - 3D lanthanide metal coordination polymer and synthesis method and application thereof

Info

Publication number: CN109627450B
Application number: CN201811308712.4A
Authority: CN
Inventors: 林佳; 柯春先; 覃路珠; 林晓明; 蔡跃鹏
Original assignee: South China Normal University
Current assignee: South China Normal University
Priority date: 2018-11-05
Filing date: 2018-11-05
Publication date: 2021-03-02
Anticipated expiration: 2038-11-05
Also published as: CN109627450A

Abstract

A3D lanthanide metal coordination polymer and a synthesis method and application thereof, wherein the chemical formula of the lanthanide metal coordination polymer Eu-PBA is { [ Eu₂(PBA)₃(H₂O)₃]∙DMF∙3H₂O}_nWhere n is a natural number from 1 to plus infinity, the structural units of the polymer beingPī space group of triclinic system, the coordination polymer Eu-PBA is composed of ligand H₂PBA，EuCl₃∙6H₂Europium O trichloride dissolved in DMF and H₂And carrying out solvothermal reaction on the O. The coordination polymer Eu-PBA is mainly applied to the aspect of detecting heavy metal/harmful metal cations in human body, and is used for Hg²⁺And Pb²⁺Has high sensitivity and selectivity.

Description

3D lanthanide metal coordination polymer and synthesis method and application thereof

Technical Field

The invention belongs to the technical field of fluorescent detection materials, and particularly relates to a 3D lanthanide metal coordination polymer and a synthesis method and application thereof.

Background

With the development of scientific technology, large amounts of toxic chemicals (such as metal cations) originating from industrial waste water, metallurgy, metal plating, chemical industry, petroleum and other industries are discharged in large quantities. At the same time, it has adverse effects on the surrounding environment and human life.

It is well known that some metal cations (e.g., Hg)²⁺，Pb²⁺，Cr³⁺，Al³⁺、Cd²⁺，Mn²⁺，Co²⁺And Ba²⁺) Has irreversible physiological damage to the human brain, nervous system and digestive system. Therefore, it is particularly important to take effective decontamination and detection measures to alleviate the currently outstanding environmental problems. Chemists have been working on methods for detecting various pollutants with high selectivity, high quantitation and excellent performance. Among them, molecular-based biosensors are considered as promising environmental bio-detection tools.

With the unlimited emission of industrial and domestic pollutants, new and effective methods for toxic ion detection have become one of the contents of intense research today. Coordination Polymers (CPs), due to their attractive topological and functional properties, have been widely used in the fields of catalysis, luminescence, chemical sensors, gas storage, separations, and the like. It is reported that N-doped aromatic carboxylic acid ligands with excellent coordination capability are crucial for the construction of coordination polymers, especially for providing potential for their further luminescent applications. However, in the multifunctional coordination polymer, designing and synthesizing various organic ligands with lewis base sites has become a leading edge of research, and introduction of pyridyl, amido, carboxyl, sulfonic acid, hydroxyl and other N-doped groups is beneficial to constructing a porous structure and optimizing the luminescent properties of selectivity, quantification and high performance. At the same time, the photophysical properties of the luminescent lanthanide coordination polymers are attributed to Ln by a combination of luminescent properties and controllable porosity in the coordination polymers³⁺The f-f transition of (a) is endowed with a large-scale fluorescence detection capability through the interaction between a host and a guest, so that the f-f transition of (a) is widely applied to fluorescence quenching chemical sensing. Even so, few reports have been made to date for the detection of Hg²⁺Or Pb²⁺An ideal fluorescent coordination polymer.

At present, Hg is available²⁺And Pb²⁺The types of the detected fluorescent probes are rare, the defects of unobvious detection signals, complex preparation process, high production cost, low selectivity, low sensitivity, poor recycling property, limited application range and the like exist generally, and the method has the advantages of simple operation and high selectionThe development of fluorescent probes/sensors with high sensitivity, low detection limit, fast response time, and stability is of paramount importance.

Disclosure of Invention

The invention aims to provide a 3D lanthanide metal coordination polymer and a synthesis method and application thereof.

The technical scheme adopted by the invention is as follows:

a 3D lanthanide series metal coordination polymer, the chemical formula of the lanthanide series metal coordination polymer Eu-PBA is { [ Eu₂(PBA)₃(H₂O)₃]·DMF·3H₂O}_nWhere n is a natural number from 1 to plus infinity, the structural units of the polymer being P_īA triclinic system space group;

the infrared absorption peaks of Eu-PBA include: 3360(s), 2332(w), 2930(w), 1657(s), 1621(m), 1544(vs), 1431(s), 1389(s), 1100(w), 777(w), 720(w), 593(m), 752(w), 593 (w);

the decomposition temperature of the Eu-PBA coordination skeleton is 330 ℃ or higher.

The synthesis method of the 3D lanthanide metal coordination polymer sequentially comprises the following steps:

1) taking DMF and H₂Mixing the O evenly to obtain a mixed solution A;

2) ligand H₂PBA，EuCl₃·6H₂Dissolving europium O trichloride in the mixed solution A in the step 1), and uniformly stirring to obtain a mixed solution B;

3) sealing the mixed solution B in a reaction kettle with a polytetrafluoroethylene lining, and reacting at a constant temperature;

4) taking out the product, cooling to room temperature, and filtering to obtain crystals;

5) washing the crystal with DMF for 3 times, and filtering to obtain crystal;

6) naturally drying the obtained crystal at room temperature to obtain a lanthanide coordination polymer Eu-PBA;

Eu-PBA is synthesized under the solvothermal condition and has a 3,3,6T13 network topological structure;

step 1) DMF and H₂The dosage of O is 3-10 mL, wherein DMF and H₂The volume ratio of O used is 1: 1;

step 2) H₂The using amount of PBA is 0.02-0.1 mmol, and EuCl₃·6H₂The usage amount of the europium O trichloride is 0.04-0.2 mmol, wherein H₂The molar ratio of PBA to europium trichloride is 1: 2;

step 3) reacting for 90-100 hours at a constant temperature of 75-85 ℃;

two different one-dimensional metal carboxylic acid chains of Eu-PBA, through PBA^2-The attachment of the ligands extends further to form a three-dimensional framework.

The 3D lanthanide metal coordination polymer is applied to the detection of heavy metal/harmful metal cations in human body, and Eu-PBA is used for Hg²⁺And Pb²⁺Has obvious fluorescence quenching effect.

The invention has the beneficial effects that:

the lanthanide series metal coordination polymer Eu-PBA is designed and synthesized under the solvothermal condition, has a 3D framework with a 3,3,6T13 network topological structure, and can be used as a fluorescent probe/sensor to detect and convert a fluorescent signal with high sensitivity due to the unique structural characteristics of the Eu-PBA. Eu-PBA to Hg²⁺And Pb²⁺Fluorescence quenching effect with high selectivity and sensitivity of cation, which can selectively detect Hg²⁺And Pb²⁺And has the advantages of low detection limit and high quenching effect, and is expected to be widely applied to the detection of daily heavy metal/harmful metal cations.

Drawings

FIG. 1 shows ligand H₂Synthetic roadmaps for PBA;

FIG. 2 shows Eu in Eu-PBA³⁺Schematic diagram of coordination mode of central metal ion;

FIG. 3 is a view of a one-dimensional Eu (1) -carboxylic acid chain;

FIG. 4 is a view of a one-dimensional Eu (2) -carboxylic acid chain;

FIG. 5 is a two-dimensional layered network structure of Eu-PBA;

FIG. 6 is a diagram of a (4,4) connected network topology of Eu-PBA;

FIG. 7 is a three-dimensional frame polyhedral view of Eu-PBA;

FIG. 8 is the 3,3,6T13 topology of Eu-PBA;

FIG. 9 is an infrared spectrum (IR) of Eu-PBA;

FIG. 10 is a thermogravimetric plot (TGA) of Eu-PBA;

FIG. 11 is a PXRD pattern of simulated Eu-PBA and experimentally obtained Eu-PBA;

FIG. 12 is H₂Fluorescence emission spectrum (λ) of BPA_ex＝339nm)；

FIG. 13 shows fluorescence excitation spectrum and emission spectrum (. lamda.) of Eu-PBA_ex＝339nm)；

FIG. 14 shows fluorescence emission spectra (λ) of Eu-PBA with different metal cations added at 300 μ M each_ex＝339nm)；

FIG. 15 shows that different metal cations are added to Eu-PBA at 300 μ M⁵D₀→⁷F₂Intensity of fluorescence (lambda) of_ex＝339nm)；

FIG. 16 shows the addition of different molar concentrations of Hg to DMF solvent²⁺The Eu-PBA fluorescence emission spectrum of (1);

FIG. 17 is Eu-PBA vs Hg in DMF solvent²⁺Stern-Volmer (SV) linear equation for fluorescence quenching effect;

FIG. 18 shows the addition of Pb to DMF solvent at different molar concentrations²⁺The Eu-PBA fluorescence emission spectrum of (1);

FIG. 19 is the reaction of Eu-PBA to Pb in DMF solvent²⁺Stern-Volmer (SV) linear equation for fluorescence quenching effect;

FIG. 20 is a graph of Hg detection at room temperature²⁺Or Pb²⁺Front and back, PXRD pattern of Eu-PBA.

Detailed Description

The present invention is described in further detail below with reference to examples and the attached drawings, it is to be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention, and various equivalent modifications of the present invention will be limited by the claims appended hereto, as those skilled in the art will recognize after reading the present invention.

Example 1

The method for synthesizing the lanthanide series metal coordination polymer Eu-PBA comprises the following steps:

1) take 3mLDMF and 3mLH₂Mixing the O evenly to obtain a mixed solution A;

2) ligand 4.5mg (0.02mmol) H₂PBA，15mg(0.04mmol)EuCl₃·6H₂Dissolving europium O trichloride in the mixed solution A in the step 1), and uniformly stirring to obtain a mixed solution B;

3) sealing the mixed solution B in a reaction kettle with a polytetrafluoroethylene lining, and reacting at the constant temperature of 75 ℃ for 90 hours;

5) washing the crystal with DMF for 3 times, and filtering to obtain crystal;

6) and naturally drying the obtained crystal at room temperature to obtain the lanthanide coordination polymer Eu-PBA.

Example 2

1) take 3mLDMF and 3mLH₂Mixing the O evenly to obtain a mixed solution A;

2) ligand 11mg (0.05mmol) H₂PBA，36.6mg(0.1mmol)EuCl₃·6H₂Dissolving europium O trichloride in the mixed solution A in the step 1), and uniformly stirring to obtain a mixed solution B;

3) sealing the mixed solution B in a reaction kettle with a polytetrafluoroethylene lining, and reacting at the constant temperature of 80 ℃ for 96 hours;

5) washing the crystal with DMF for 3 times, and filtering to obtain crystal;

Example 3

1) take 5mLDMF and 5mLH₂Mixing the O evenly to obtain a mixed solution A;

2) ligand 15mg (0.07mmol) H₂PBA，51mg(0.14mmol)EuCl₃·6H₂Dissolving of europium O trichlorideUniformly stirring the mixed solution A in the step 1) to obtain a mixed solution B;

3) sealing the mixed solution B in a reaction kettle with a polytetrafluoroethylene lining, and reacting at the constant temperature of 78 ℃ for 95 h;

5) washing the crystal with DMF for 3 times, and filtering to obtain crystal;

Example 4

1) take 7mLDMF and 7mLH₂Mixing the O evenly to obtain a mixed solution A;

2) ligand 20mg (0.09mmol) H₂PBA，66mg(0.18mmol)EuCl₃·6H₂Dissolving europium O trichloride in the mixed solution A in the step 1), and uniformly stirring to obtain a mixed solution B;

3) sealing the mixed solution B in a reaction kettle with a polytetrafluoroethylene lining, and reacting at the constant temperature of 82 ℃ for 98 hours;

5) washing the crystal with DMF for 3 times, and filtering to obtain crystal;

Example 5

1) take 10mLDMF and 10mLH₂Mixing the O evenly to obtain a mixed solution A;

2) ligand 22mg (0.1mmol) H₂PBA，73mg(0.2mmol)EuCl₃·6H₂Dissolving europium O trichloride in the mixed solution A in the step 1), and uniformly stirring to obtain a mixed solution B;

3) sealing the mixed solution B in a reaction kettle with a polytetrafluoroethylene lining, and reacting at the constant temperature of 85 ℃ for 100 hours;

5) washing the crystal with DMF for 3 times, and filtering to obtain crystal;

Ligand H in the above examples₂The synthesis method of PBA is as follows:

dispersing 3-bromopyridine hydrochloride, 4-carboxyphenylboronic acid and sodium carbonate in toluene, adding palladium tetrakis (triphenylphosphine) to react for 8-10H at 80-100 ℃ to obtain 3-pyridine-4-benzoic acid, adding 3-pyridine-4-benzoic acid into thionyl chloride, refluxing at 60-80 ℃ to obtain 3-pyridine-4-ylbenzoyl chloride, dispersing the 3-pyridine-4-ylbenzoyl chloride and 5-aminoisophthalic acid with DMF (dimethyl formamide), placing in an ice water bath to react for 2-4H, pouring the reaction mixture into water, separating out solids, filtering and drying to obtain H₂PBA, as in fig. 1.

The synthesis method belongs to the prior art, and the specific preparation method is disclosed in patent 201810072884.X & lt & gt & lt/EN & gt & lt.

The structure and application of the coordination polymer Eu-PBA are analyzed through data and conclusions.

1) The following is the structural analysis of the coordination polymer Eu-PBA:

x-ray diffraction measurements at room temperature by Bruker APEX II diffractometer using graphite monochromatic Mo-Ka rays

And (4) measuring. Absorption correction and space group determination are performed by the multi-scan method using SADABS and XPREP in APEX2, respectively. The structure was solved by direct method using the SHELXL program (SHELXTL-2014), and using F²The full matrix least squares refines the structure. In the final cycle, the theoretical position of the organic hydrogen atom will be calculated using the isotropic displacement parameters of the organic hydrogen atom. Since the free solvent molecules are highly disordered in the structure, interference of their scattering is eliminated by the SQUEEZE program of PLATON, and the final result is used for the determination of the structure.

The refined structural data for Eu-PBA is summarized in table 1, and table 2 lists selected bond lengths and angles, as follows:

TABLE 1 refined Crystal and Structure data of Eu-PBA

TABLE 2 bond length of Eu-PBA

Angle of harmony key (°)

The structural analysis shows that Eu-PBA has P ī triclinic space group. According to fig. 2, the Eu (1) ion is octadentate, in a distorted, double-capped triangular prism geometry, coordinated with one pyridine nitrogen atom, six carboxylate oxygen atoms from six different ligands, and one oxygen atom from coordinated water, respectively. Furthermore, the Eu (2) ion is also octadentate, and its coordination environment is different from that of the Eu (1) ion. Each Eu (2) ion passing through six carboxylate oxygen atoms from five ligands and through two coordinated H atoms₂The two oxygen atoms of the O molecule are linked.

Furthermore, each adjacent Eu (1) center is connected by a carboxylic acid group via a bidentate chelate/bridge coordination mode to build up a one-dimensional Eu (1) -carboxylic acid chain, as shown in fig. 3.

Similarly, adjacent Eu (2) centers are linked with carboxylic acid groups to form 1D Eu (2) -carboxylic acid chains, as in fig. 4.

Eu-O bond length of 2.427(5) to 2.615(5), and O-Eu-O bond angle of 51.00(16) to 152.20(17) °, 1D Eu (1) chain and Eu (2) carboxylic acid chain pass through PBA^2-The carboxylic acid oxygen and pyridine nitrogen atoms of the ligand are linked to each other to form a 2D (4,4) linked layered lattice framework, as shown in fig. 5 and 6.

Next, the carboxylic acid oxygen atoms and pyridine nitrogen atoms from the numerous ligands are constructed as nodes into a 3D framework, as shown in fig. 7.

Each ligand acts as a 3-connected node, while the Eu-binuclear unit acts as a 6-connected node, and Eu-PBA has a 3,3,6T13 network topology, which

Symbol (4. 5)²)₂(4²·5²·10·6·7²)(5⁸·6⁴·10·6·7²) As in fig. 8.

C₆₃H₅₅Eu₂N₇O₂₂The theoretical value of the content of the non-metals is as follows: c, 48.32%; h, 3.54%; n, 6.26%; c, 48.30% by Elemental Analysis (EA); h, 3.57%; n,6.22 percent. Eu-PBA measurement by Infrared Spectroscopy (IR) (KBr, cm)^-1) 3360(s), 2332(w), 2930(w), 1657(s), 1621(m), 1544(vs), 1431(s), 1389(s), 1100(w), 777(w), 720(w), 593(m), 752(w), 593(w), as in FIG. 9.

To explore the thermal stability of Eu-PBA, thermogravimetric analysis (TGA) was performed by heating from room temperature to 800 ℃ at a heating rate of 10 ℃/min under nitrogen atmosphere. As shown in FIG. 10, Eu-PBA lost weight between room temperature and 330 ℃, corresponding to the loss of all free solvent molecules (measured 12.07%; calculated 11.57%). As the temperature increases, the entire frame collapses due to decomposition resulting in a dramatic weight loss above 330 ℃.

The measured PXRD pattern of Eu-PBA is consistent with the simulated PXRD pattern, which shows that the phase purity is high, as shown in figure 11.

2) The following is an analysis of the application aspect of the coordination polymer Eu-PBA:

for better application of Eu-PBA for detection of cations, H is measured in the visible region₂Fluorescence spectra of PBA and coordination polymer Eu-PBA. When the excitation wavelength isAt 339nm, H is due to pi → pi and/or pi → n electron transition₂The PBA had a strong emission peak at a wavelength of 460nm, as shown in fig 12.

At the same time, Eu³⁺The respective characteristic peaks of the ion transitions appear at 582, 595, 619, 654 and 702nm, respectively, as shown in FIG. 13, which correspond to those at 582, 595, 619, 654 and 702nm, respectively⁵D₀→⁷F_J(J-0-4). However, the fluorescence spectrum of Eu-PBA does not have a strong emission peak (λ) of the ligand_em460nm), which proves H₂PBA ligands can be reacted with Eu³⁺Coordination interaction as an efficient detection of cation Eu³ ⁺The fluorescence quencher of (1).

Sensing and quenching effect experiments of Eu-PBA and different metal cations:

soaking 50mg fine powder of Eu-PBA in 100mL DMF solvent for 24 hr, performing ultrasonic treatment for 30 min to obtain uniform turbid suspension, transferring 1.8mL suspension into cuvette container, and collecting MCl_nAqueous solution (3mM, 0.2mL) (M)ⁿ⁺＝Al³⁺，Cr³⁺，Cd²⁺，Mn²⁺，Co²⁺，Ba²⁺，Hg²⁺And Pb²⁺(ii) a n-2-3) were added separately to the suspension to produce a series of homogeneous mixtures with the same cation concentration (300 μ M).

FIG. 14 shows Eu for a suspension containing different cations when excited³⁺The characteristic emission peak of the ion, while the fluorescence intensity varies with the added cation.

The addition of the metal cations weakens the fluorescence intensity of the Eu-PBA to different degrees, and the quenching effects are as follows in sequence: p b²⁺>Hg²⁺>Ba²⁺>Mn²⁺>Co²⁺>Cd²⁺>Cr³⁺>Al³⁺Wherein Eu is³⁺Correspond to⁵D₀→⁷F₂The maximum characteristic peak intensity of the transition is shown in fig. 15. The fluorescence intensity of Eu-PBA decreases slightly after most cations are added to the suspension. However, for Hg²⁺And Pb²⁺In addition, the fluorescence signal of Eu-PBA is sharply reduced, and the quenching effect is obviousIt was shown that the coordination polymer Eu-PBA can sensitively and selectively detect Hg from the above-mentioned numerous cations²⁺And Pb²⁺A cation. In the excited state (lambda)_ex339nm), a sharp fluorescence quenching of Eu-PBA occurs by a photo-induced electron transfer (PET) effect, resulting in a significant weakening phenomenon of fluorescence intensity. In the excited state, due to Hg²⁺Or Pb²⁺Production of ligand moiety as a novel luminophore, Hg²⁺And Pb²⁺The ions produce quenching by energy and/or electron transfer. In contrast, introduction of other metal cations (Al)³⁺，Cr³⁺，Cd²⁺，Mn²⁺，Co²⁺And Ba²⁺) There is no quenching effect so pronounced, probably due to the fact that Eu-PBA can transfer energy to Eu³⁺Ions and simultaneous blocking from H₂PBA ligands to Eu³⁺The intramolecular energy transfer path of the ion, and thus has no significant effect on the fluorescence intensity.

In order to further explore the Hg of the target²⁺And Pb²⁺Varying the Hg in suspension by a concentration gradient²⁺And Pb²⁺To investigate the quenching effect of Eu-PBA. The results show that Hg is associated with heavy metal ions²⁺And Pb²⁺The increase in concentration (from 10. mu.M to 500. mu.M, respectively) significantly reduced the fluorescence intensity. The results show that the quenching effect is related to Hg²⁺And Pb²⁺The concentration of (c) is linear, as shown in FIGS. 16-19. The Stern-Volmer (SV) equation can be used to quantitatively calculate the fluorescence quenching efficiency. By the Stern-Volmer equation: i is₀/I＝1+K_sv[M]The quenching constant (K) was calculated_sv) In which I₀And the value of I is the addition of HgCl₂Or PbCl₂Fluorescence intensity of the suspension before and after, [ M ]]Is HgCl₂Or PbCl₂The molar concentration of (c). In addition, the detection limit (D) may be calculated based on the equation D-3 σ/K, where σ and K correspond to the standard deviation and the slope (K), respectively_sv). Calculated quenching constant (K)_sv) Are respectively 8743 (for Hg)²⁺) And 43988 (for Pb)²⁺)M^-1Showing that the coordination polymer Eu-PBA is opposite to Pb²⁺Has more excellent and sensitive quenching effect. ComputingThe detection limits (D) were 341.20. mu.M and 68.13. mu.M, respectively, indicating that the coordination polymers Eu-PBA were responsible for Hg²⁺And Pb²⁺And (3) cationic fluorescence sensing characteristics.

To verify the stability of Eu-PBA, the immersion of Eu-PBA in the presence of Hg was measured²⁺Or Pb²⁺The PXRD patterns of the front and back PXRD patterns in the DMF solution are highly consistent, and the result shows that the framework of the Eu-PBA is not obviously changed, so that the Eu-PBA has good solvent stability and chemical stability, as shown in figure 20.

The above description is only a part of the embodiments of the present invention, but the design concept of the present invention is not limited thereto, and any insubstantial modifications made by the design concept should fall within the scope of infringing the present invention. However, any simple modification, equivalent change and modification of the above embodiments according to the technical essence of the present invention will still fall within the protection scope of the technical solution of the present invention without departing from the content of the technical solution of the present invention.

Claims

1. A3D lanthanide metal coordination polymer is characterized in that the lanthanide coordination polymer Eu-PBA has a chemical formula { [ Eu₂(PBA)₃(H₂O)₃]∙DMF∙3H₂O}_nWherein n is a natural number from 1 to positive infinity, the structural units of the polymer belonging to the P ī triclinic space group;

the lanthanide coordination polymer Eu-PBA is synthesized under the solvothermal condition and has a 3,3,6T13 network topology structure.

2. The 3D lanthanide metal coordination polymer of claim 1, wherein the infrared absorption peak of Eu-PBA comprises: 3360(s), 2332(w), 2930(w), 1657(s), 1621(m), 1544(vs), 1431(s), 1389(s), 1100(w), 777(w), 720(w), 593(m), 752(w), 593 (w).

3. The 3D lanthanide metal coordination polymer of claim 1, wherein the decomposition temperature of the coordination backbone of Eu-PBA is 330 ℃ or higher.

4. A method for synthesizing a 3D lanthanide metal coordination polymer as defined in any of claims 1 to 3, characterized in that it is prepared by the following steps in sequence:

1) taking DMF and H₂Mixing the O evenly to obtain a mixed solution A;

2) ligand 5- (4-pyridin-3-yl-benzoylamino) -m-phthalic acid H₂PBA，EuCl₃∙6H₂Dissolving europium O trichloride in the mixed solution A in the step 1), and uniformly stirring to obtain a mixed solution B;

5) washing the crystal with DMF for 3 times, and filtering to obtain crystal;

5. The method of synthesizing a 3D lanthanide metal coordination polymer as defined in claim 4, wherein Eu-PBA is synthesized under solvothermal conditions, having a 3,3,6T13 network topology.

6. The method of synthesizing a 3D lanthanide metal coordination polymer as defined in claim 4 or 5, wherein step 1) DMF and H₂The dosage of O is 3-10 mL.

7. The method of synthesizing a 3D lanthanide metal coordination polymer as recited in claim 4 or 5, wherein step 2) H₂The using amount of PBA is 0.02-0.1 mmol, and EuCl₃∙6H₂The usage amount of the europium O trichloride is 0.04-0.2 mmol.

8. The method for synthesizing the 3D lanthanide metal coordination polymer according to claim 4 or 5, wherein the step 3) is performed at a constant temperature of 75-85 ℃ for 90-100 h.

9. The method for synthesizing 3D lanthanide metal coordination polymer as claimed in claim 4 or 5, wherein two different one-dimensional metal carboxylic acid chains in Eu-PBA pass through PBA^2-The attachment of the ligands extends further to form a three-dimensional framework.

10. Use of a 3D lanthanide metal coordination polymer as defined in any of claims 1 to 3 for heavy metal/human body hazardous metal cation detection, wherein Eu-PBA is responsible for Hg²⁺And Pb²⁺Has fluorescence quenching effect.