CN108517207B - Tb-MOFs PA fluorescence detection probe and preparation method and application thereof - Google Patents

Abstract

The invention discloses a Tb-MOFs PA fluorescence detection probe, which has the following chemical formula: { (C)₂H₆NH₂)₂[Tb₂(ptptc)₂(DMF)(H₂O)]·DMF·6H₂O } n, the invention also discloses a preparation method of the detection probe, which comprises the steps of mixing terbium nitrate hexahydrate, 3 ', 5, 5' -terphenyl tetracarboxylic acid and HNO₃Adding N, N-dimethylformamide and deionized water into a polytetrafluoroethylene inner container of a hydrothermal synthesis kettle, and uniformly stirring to obtain a mixed solution; packaging the obtained mixed solution and putting the packaged mixed solution into a reaction kettle, then putting the reaction kettle into an oven, heating the reaction kettle to 160 ℃, and reacting for 72 hours; and taking the reaction kettle out of the oven, cooling to room temperature, washing the reacted mixed solution with DMF, and drying to obtain the finished product. The probe prepared by the invention has the characteristics of good selectivity, high sensitivity and high response speed.

Description

Tb-MOFs PA fluorescence detection probe and preparation method and application thereof

Technical Field

The invention belongs to the technical field of chemical sensing, and particularly relates to a Tb-MOFs PA fluorescence detection probe, and a preparation method and application of the detection probe.

Background

2,4, 6-trinitrophenol, also known as Picric Acid (hereinafter abbreviated as PA), is widely used for manufacturing electric detonators, fireworks, shells, dyes, medicines, leather and the like. 2,4, 6-trinitrophenol is easy to dissolve in water, can cause serious water and soil pollution when being used in a large amount, and can cause dizziness, headache, induced dermatitis and liver and kidney damage when contacting PA in a large amount for a long time. In addition, PA is used as a high explosive with high explosiveness and low safety, and causes great harm to public safety.

Instrumental detection methods such as high performance liquid chromatography, Raman spectroscopy, mass spectrometry and the like are the main methods for PA detection. However, such methods still have some inherent problems, such as the need for expensive large-scale instruments, poor detection selectivity, high detection cost, and the like. The fluorescent probe detection method has the characteristics of rapidness, simple and convenient operation and specific selection, and meets the detection requirements of real-time, high efficiency and high selectivity.

Disclosure of Invention

The invention aims to provide a Tb-MOFs PA fluorescence detection probe which has the characteristics of good selectivity, high sensitivity and high response speed.

The invention also aims to provide a preparation method of the Tb-MOFs PA fluorescence detection probe.

The technical scheme adopted by the invention is that the Tb-MOFs PA fluorescent detection probe has the following chemical formula:

{(C₂H₆NH₂)₂[Tb₂(ptptc)₂(DMF)(H₂O)]·DMF·6H₂O}n。

the second technical scheme adopted by the invention is that the preparation method of the Tb-MOFs PA fluorescence detection probe specifically comprises the following steps:

step 1, terbium nitrate hexahydrate, 3 ', 5, 5' -terphenyltetracarboxylic acid and HNO₃Adding N, N-dimethylformamide and deionized water into a polytetrafluoroethylene inner container of a hydrothermal synthesis kettle, and uniformly stirring to obtain a mixed solution;

step 2, packaging the mixed solution obtained in the step 1 and putting the packaged mixed solution into a reaction kettle, then putting the reaction kettle into an oven to heat the mixed solution to 160 ℃, and enabling the mixed solution to react in the reaction kettle for 72 hours;

and 3, taking the reaction kettle out of the oven, cooling to room temperature, taking the reacted mixed solution out of the reaction kettle, washing with DMF, and drying to obtain the product.

The invention has the advantages that the prepared fluorescence corresponding type PA detection probe can visually identify PA in real time according to the change of the fluorescence intensity of the probe; the fluorescence spectrometer is used for quantitatively measuring the concentration of the PA, the detection line can reach 100 nanomole, and the technical defects of low specificity identification capability, complex detection operation, low detection sensitivity and the like in the conventional PA detection technology are overcome.

Drawings

FIG. 1(a) is a diagram showing the structure of an asymmetric unit of the Tb-MOFs PA fluorescence detection probe of the present invention;

FIG. 1(b) shows that two carboxylate groups of the Tb-MOFs PA fluorescence detection probe of the present invention are bridged to form a bimetal [ Tb ]₂(μ₂-COO)₂(COO)₆]^2-A diagram of structural units of cluster bases;

FIG. 2(a) is a two-dimensional layered structure diagram of the Tb-MOFs PA fluorescence detection probe of the present invention on the ab plane;

FIG. 2(b) is a three-dimensional frame structure diagram of the Tb-MOFs PA fluorescence detection probe presented on bc surface;

FIG. 2(c) is a structural diagram of a Tb-MOFs PA fluorescence detection probe having a one-dimensional tunnel in the direction b;

FIG. 3 is a powder diffraction test spectrum of the Tb-MOFs PA fluorescence detection probe of the present invention;

FIG. 4 shows Tb-MOFs PA fluorescence detection probe and ligand H of the present invention₄ptptc solid state fluorescence spectrum;

FIG. 5 is a test chart of the recognition selectivity of different analytes by using a methanol Tb-MOFs PA fluorescent detection probe of 1 mg/mL;

FIG. 6 is a graph of the recognition selectivity test using a 1mg/mL methanolic Tb-MOF fluorescent probe system in the presence of PA and other analytes;

FIG. 7 is a graph of response time of a methanol Tb-MOF fluorescent probe system with 1mg/mL to PA fluorescence;

FIG. 8 is a response test chart of a 1mg/mL methanol Tb-MOF fluorescent probe system for different concentrations of PA;

FIG. 9 is a non-linear fit graph of the fluorescent response of a 1mg/mL methanolic Tb-MOF fluorescent probe system to different concentrations of PA.

Detailed Description

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

The Tb-MOFs PA fluorescent detection probe has the following chemical formula: { (C)₂H₆NH₂)₂[Tb₂(ptptc)₂(DMF)(H₂O)]·DMF·6H₂O}n。

In the formula, H₄ptptc is terphenyl-2, 2 ', 4, 4' -tetracarboxylic acid; the metal-organic framework belongs to the triclinic system,

space group, the structure of which has two dimethylamine cations, so that the crystal structure is a three-dimensional anion framework with one-dimensional pores. Tb with two coordination environments in the crystal structure³⁺Wherein Tb1³⁺Coordination mode of (2) with Tb2³⁺Similarly, Tb1³⁺And Tb2³⁺All form an octadentate structure by coordination with 6 chelated carboxylic acid oxygen atoms, two vicinal carboxylic acid oxygen atoms, and Tb1^{3 +}Coordinated with a DMF Tb2³⁺And a H₂The coordination of O forms a nonadentate tetradecahedron structure. Tb1 in crystal structure³⁺And Tb2³⁺The formed coordination units are bridged by two carboxylate radicals to form a bimetal [ Tb ]₂(μ₂-COO)₂(COO)₆]^2-Cluster base, ptptc^4-The carboxyl group of the ligand is represented by mu₆The coordination mode is connected with the cluster base of the adjacent bimetal to form a two-dimensional layered structure; mu.s₄Ptptc in bridged coordination mode^4-The ligand is connected with the adjacent two-dimensional layers to form a three-dimensional metal organic framework structure with one-dimensional pore channels. The crystal structure has a quadrilateral one-dimensional pore channel in the direction a, and the pore diameter is

A quadrilateral pore canal and a parallelogram pore canal exist in the direction b, and the pore diameters are respectively

And

dimethylamine cation and solvent molecules can be present in the pores, with a porosity of 35% as calculated by PLATON.

The invention also provides a preparation method of the Tb-MOFs (Tb-MOFs is an abbreviation of a terbium metal organic framework) PA fluorescence detection probe, and the preparation method of the Tb-MOFs PA fluorescence detection probe provided by the invention takes terbium nitrate hexahydrate as a metal source and takes 3,3 ', 5, 5' -terphenyltetracarboxylic acid (H) as a metal source₄ptptc) as ligand, N-dimethylformamide (DMF,4mL) and deionized (4mL) as solvent, comprising the following steps:

step 1, 8.7mg,0.02mmol terbium nitrate hexahydrate, 4mg,0.01mmol of 3,3 ', 5, 5' -terphenyltetracarboxylic acid (H)₄ptptc), three drops of 6mol/L HNO₃Adding N, N-Dimethylformamide (DMF) and 4ML deionized water into a polytetrafluoroethylene inner container of a 25ML hydrothermal synthesis kettle, and uniformly stirring;

step 2, packaging the mixed solution obtained in the step 1 and putting the packaged mixed solution into a reaction kettle, then putting the reaction kettle into an oven to heat the mixed solution to 160 ℃, and enabling the mixed solution to react in the reaction kettle for 72 hours;

and 3, taking the reaction kettle out of the oven at room temperature, taking the reacted mixed solution out of the reaction kettle, washing with DMF, and drying to obtain the product.

The Tb-MOFs probe prepared by the method is applied to fluorescence recognition of PA.

The application method of the Tb-MOFs PA fluorescence detection probe provided by the invention is not particularly limited. The test can be carried out by dispersing the probe molecule in a solvent such as ethanol, methanol, N-dimethylformamide or the like at room temperature. In order to research the specific recognition effect of the probe molecule on the PA molecule, methanol is used as a solvent to prepare a probe solution with the concentration of 1 mg/mL; 10mM of methanol or ethanol solution of p-nitrobenzoic acid (PNBA), m-nitroaniline (m-NA), o-nitroaniline (o-NA), o-nitrophenol (o-NP), 2,4, 6-trinitrophenol (PA), Nitrobenzene (NB),2, 4-dinitrophenylhydrazine (NB), benzene (benzozene), phenol (phenol), aniline (aniline) and nicotinic acid (3-NC) is prepared respectively.

Adding 50 mu M of different organic compounds into a 2mL methanol Tb-MOFs fluorescent probe system with the concentration of 1mg/mL to perform selectivity test on probe molecules; adding 50 mu M PA and 50 mu M of the different organic compounds into a 2mL 1mg/mL methanol Tb-MOFs fluorescent probe system to carry out a mixed selectivity test of probe molecules; adding 1 mu M, 10 mu M, 100 mu M and 200 mu M PA into a 2mL 1mg/mL methanol Tb-MOFs fluorescent probe system, recording the fluorescence intensity of the system at intervals of 30 seconds, and testing the detection response time; the concentration response test is carried out by adding 0.1-200 mu M of PA into 2mL of 1mg/mL methanol Tb-MOFs fluorescent probe system.

The probe responds to PA with the concentration of 0.1-200 mu M and shows a good nonlinear relation (R)²0.9994). In the concentration range, a fluorescence detection method can be adopted to carry out quantitative detection on PA, and the lowest detection concentration of PA is 100nM (the excitation wavelength is 325 nM); the probe has the effect of instant detection, and the corresponding time is less than 30 seconds.

Example 1

Preparation of Tb-MOFs PA fluorescence detection probe

Terbium nitrate hexahydrate (8.7mg,0.02mmol), 3 ', 5, 5' -terphenyltetracarboxylic acid (4 mg,0.01mmol) and 3 drops of 6mol/L HNO₃Adding N, N-dimethylformamide (4mL) and deionized water (4mL) into a polytetrafluoroethylene inner container of a 25mL hydrothermal synthesis kettle, and uniformly stirring; packaging the prepared mixed solution, putting the packaged mixed solution into a reaction kettle, putting the reaction kettle into an oven, heating to 160 ℃, and reacting for 72 hours; filtering, washing and drying to obtain white crystals which are the Tb-MOFs fluorescent probe material.

Performing structural, purity and fluorescence characterization on the prepared functional metal-organic framework based on the rare earth metal cluster:

1) Tb-MOFs structural testing

Single Crystal diffraction data Collection with Mo/K a radiation at 150K using a Bruker D8Venture diffractometer

Collected in omega/2 theta scan mode, absorption correction using SADABS program. By direct structural decomposition, howeverThen, the coordinates of all non-hydrogen atoms are obtained by a difference Fourier method. The calculation work is done on a PC using the SHELXTL package. Detailed crystallographic data are shown in Table 1, and structures are shown in attached figures 1-2; wherein FIG. 1(a) is a diagram showing the structure of an asymmetric unit of a Tb- MOF 2,4, 6-trinitrophenol fluorescence detection probe; FIG. 1(b) shows that the double carboxylate bridging of Tb- MOF 2,4, 6-trinitrophenol fluorescence detection probe forms a bimetal [ Tb ]₂(μ₂-COO)₂(COO)₆]^2-A diagram of the structural units of the cluster base. FIG. 2(a) is a two-dimensional layered structure diagram of a Tb- MOF 2,4, 6-trinitrophenol fluorescence detection probe on an ab plane; FIG. 2(b) is a diagram showing the structure of a three-dimensional framework of a Tb- MOF 2,4, 6-trinitrophenol fluorescence detection probe appearing on the bc plane; FIG. 2(c) shows that the Tb- MOF 2,4, 6-trinitrophenol fluorescence detection probe has a one-dimensional pore diagram in the direction b.

TABLE 1

^aR₁＝Σ||F_o|-|F_c||/Σ|F_o|.^bwR₂＝[Σ[w(F_o ²-F_c ²)²]/Σw(F_o ²)²]^1/2,where w ＝1/[σ²(F_o)²+(aP)²+bP]and P＝(F_o ²+2F_c ²)/3.

The structures of fig. 1 and 2 show that: Tb-MOFs is a crystal structure belonging to the triclinic system,

a space group; the crystal structure is a functional metal-organic framework based on rare earth metal clusters, and Tb in two coordination environments exists in the crystal structure³⁺Tb in two coordination environments³⁺Formation of [ Tb ] by carboxylate bridging₂(μ₂-COO)₂(COO)₆]^2-Of a bimetallic cluster of, wherein Tb1³⁺Coordination mode of (2) with Tb2³⁺Similarly, Tb1³⁺And Tb2³⁺All form an octadentate structure by coordination with 6 chelated carboxylic acid oxygen atoms, two bridging carboxylic acid oxygen atoms, and Tb1³⁺Coordinated with a DMF Tb2³⁺And a H₂The coordination of O forms a nonadentate tetradecahedron structure. Tb1 in crystal structure³⁺And Tb2³⁺The formed coordination units are bridged by two carboxylate radicals to form a bimetallic cluster group, ptptc^4-The carboxyl group of the ligand is represented by mu₆The coordination mode links the cluster bases of adjacent double metals to form a two-dimensional layered structure; mu.s₄Ptptc in bridged coordination mode^4-The ligand is linked with the adjacent two-dimensional layer to form a three-dimensional metal organic framework structure with one-dimensional pore channels. The crystal structure has a quadrilateral one-dimensional pore channel in the direction a, a quadrilateral pore channel and a parallelogram pore channel in the direction b, and dimethylamine cations and solvent molecules can exist in the pore channels.

2) Tb-MOFs PA fluorescence detection Probe powder diffraction test (PXRD):

the Tb-MOFs fluorescent probe prepared by the invention is tested on a Bruker D8 ADVANCE powder Diffractometer (Bruker D8 ADVANCE X-Ray Diffractometer) at room temperature, and the spectrogram is shown in figure 3. The main diffraction peak of the test spectrogram is consistent with the simulated peak based on the crystal data, which indicates that the Tb-MOFs prepared by the method has better purity. The abscissa 2theta/degree in FIG. 3 represents the X-ray diffraction spectrum obtained by scanning the entire diffraction region at an angle of 2theta, and the intensity of the diffraction peak at different diffraction angles is represented as the ordinate.

3) Tb-MOFs PA fluorescence detection probe solid fluorescence test

The Tb-MOFs fluorescent probe prepared by the invention is tested on an Agilent luminescence spectrometer (Agilent Cary Eclipse fluorescence spectrometer) at room temperature, the excitation wavelength is 325nm, the spectrogram is shown in figure 4, and as can be seen from figure 4, the Tb-MOFs fluorescent probe mainly comprises 5 fluorescence emission peaks, and the positions of the fluorescence emission peaks are 363nm,491 nm,546nm,586nm and 621nm respectively. The above fluorescence emission peaks can be respectivelyAttributing to ligands pi-pi transition and terbium⁵D₄→⁷F₆,⁵D₄→⁷F₅,⁵D₄→⁷F₄and⁵D₄→⁷F₃Characteristic emission peak.

Example 2:

this example is a response test for a single set of analytes for Tb-MOFs probes prepared in example 1.

Preparing Tb-MOFs probe suspension with the concentration of 1mg/mL by using methanol as a solvent, and adding 50 mu M of p-nitrobenzoic acid (PNBA), M-nitroaniline (M-NA), o-nitroaniline (o-NA), o-nitrophenol (o-NP), 2,4, 6-trinitrophenol (PA), Nitrobenzene (NB),2, 4-dinitrophenylhydrazine (2,4-DNPH), Benzene (Benzene), Phenol (Phenol), Aniline (Aniline) and nicotinic acid (3-NC) into 2mL of the probe suspension respectively. The relative fluorescence intensities of the probe suspension before and after addition of different organic molecules were measured, and the results are shown in FIG. 5 (F)₀The relative fluorescence intensity of a suspension containing no organic molecules added thereto, and F the relative fluorescence intensity of a suspension containing organic molecules added thereto). As can be seen in FIG. 5, fluorescence is significantly reduced with only PA added to the probe solution. Compared with PA, other structural analogs have no obvious effect on the probe molecules. The experimental results obtained in this example show that the probe molecule can specifically recognize and detect PA.

Example 3

This example is a response test for the two-component analytes for Tb-MOFs probe prepared in example 1.

Preparing Tb-MOFs probe suspension with a concentration of 1mg/mL by using methanol as a solvent, and adding 50 μ M of PA and any one of p-nitrobenzoic acid (PNBA), M-nitroaniline (M-NA), o-nitroaniline (o-NA), o-nitrophenol (o-NP), 2,4, 6-trinitrophenol (PA), Nitrobenzene (NB),2, 4-dinitrophenylhydrazine (2,4-DNPH), Benzene (Benzene), Phenol (Phenol), Aniline (Aniline) and nicotinic acid (3-NC) into 2mL of the probe suspension. The relative fluorescence intensity before and after adding the probe suspension to the analyte was measured, and the result is shown in FIG. 6 (F)₀For the relative fluorescence intensity of the suspension without analyte, F is the addition of bisRelative fluorescence intensity of the suspension after analyte composition). As can be seen in fig. 6, the addition of other analytes did not affect the recognition effect of the probe on PA. The experimental results obtained in this example show that the probe molecule can specifically recognize and detect PA. Analyte represents an Analyte.

Example 4:

this example is a Tb-MOFs probe prepared in example 1, tested for response time to different concentrations of PA.

Tb-MOFs probe suspension at a concentration of 1mg/mL was prepared using methanol as a solvent, and 1. mu.M, 10. mu.M, 100. mu.M and 200. mu.M PA were added to 2mL of the above-mentioned probe suspension, respectively. The fluorescence intensity of the probe was recorded every 30 seconds, and the results are shown in FIG. 7, with the abscissa representing the time of addition of PA and the ordinate representing the relative fluorescence intensity. As can be seen from fig. 7: after the addition of PA, the response was complete within 30 seconds. The experimental result obtained in the embodiment shows that the probe molecule can rapidly react with PA to give fluorescence signal change, and can be used for real-time monitoring of PA.

Example 5:

this example is a response test of Tb-MOFs probe prepared in example 1 to different concentrations of PA.

Methanol is used as a solvent to prepare Tb-MOFs probe suspension with the concentration of 1mg/mL, and 0.1-200 mu M PA is added into 2mL of the probe suspension. The relative fluorescence intensities of the probe suspension before and after addition of the analyte were measured, and the results are shown in FIG. 8 (F)₀Relative fluorescence intensity of the suspension without the added analyte, and F relative fluorescence intensity of the suspension after the added two-component analyte). As can be seen from FIG. 8, the fluorescence intensity of Tb-MOFs probe rapidly decreased with the increase of PA concentration, and the lowest detection concentration reached 100 nM. The experimental results obtained in this example show that the probe responds well to the increase in PA concentration with respect to the fluorescence intensity.

Example 6:

this example is a non-linear fit of the results of the fluorescence response test for different concentrations of PA with the Tb-MOFs probe prepared in example 1.

Tb-MOFs probe suspension at a concentration of 1mg/mL was prepared using methanol as a solvent, and 0 was added to 2mL of the above probe suspension.1-200. mu.M PA. The relative fluorescence intensities of the probe suspension before and after addition of the analyte were measured, and the results are shown in FIG. 8 (F)₀Relative fluorescence intensity of the suspension without the added analyte, and F relative fluorescence intensity of the suspension after the added two-component analyte). The fluorescence intensities obtained in FIG. 8 were plotted against the PA concentration and fitted non-linearly to obtain FIG. 9. As can be seen from FIG. 9, the fluorescence intensity of the probe showed a good nonlinear relationship with the PA concentration in the range of 0.1 to 200. mu.M. The nonlinear equation is:

the experimental result obtained in the embodiment shows that the probe has the application potential of quantitatively detecting PA.

The Tb-MOFs PA fluorescence detection probe has the characteristics that PA can be visually identified according to the change of the fluorescence intensity of the probe; the portable fluorescence spectrometer can be used for qualitatively determining the PA in real time, and the defects of low specificity identification capability, complex detection operation, incapability of monitoring in real time and the like in the conventional PA detection technology are overcome.

Claims (1)

1. The application of the Tb-MOFs PA fluorescence detection probe is characterized in that: the application in the fluorescence recognition of PA;

the Tb-MOFs PA fluorescent detection probe has the following chemical formula: { (C)₂H₆NH₂)₂[Tb₂(ptptc)₂(DMF)(H₂O)]·DMF·6H₂O}n；

Wherein PA is 2,4, 6-trinitrophenol which is also called picric acid;

H₄ptptc is terphenyl-2, 2 ', 4, 4' -tetracarboxylic acid;

the preparation method of the Tb-MOFs PA fluorescence detection probe specifically comprises the following steps:

step 1, terbium nitrate hexahydrate, 3 ', 5, 5' -terphenyltetracarboxylic acid and HNO₃Adding N, N-dimethylformamide and deionized water into a polytetrafluoroethylene inner container of a hydrothermal synthesis kettle, stirring uniformly,obtaining a mixed solution;

step 2, packaging the mixed solution obtained in the step 1 and putting the packaged mixed solution into a reaction kettle, then putting the reaction kettle into an oven to heat the mixed solution to 160 ℃, and enabling the mixed solution to react in the reaction kettle for 72 hours;

and 3, taking the reaction kettle out of the oven, cooling to room temperature, taking the reacted mixed solution out of the reaction kettle, washing with DMF, and drying to obtain the product.

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