A rare earth europium (III) probe material, a preparation method thereof and application thereof as a fluorescent detection material

Abstract

A rare earth europium(III) probe material, its preparation method, and its application as a fluorescent detection material, relating to the field of luminescent materials technology, wherein the aforementioned rare earth europium(III) probe material has the following chemical formula: [Eu(C 24 H 16 O6) 1.5 (2,2′-bipy)(DMF)] n The preparation method involves adding 2,5-bis(4-methylbenzoyl)terephthalic acid to a container, adding a mixed solvent consisting of water, N,N-dimethylformamide, and methanol, heating in a water bath to dissolve it, then adding europium nitrate hexahydrate to this mixed solution, continuing heating and stirring, transferring the resulting mixed solution to a test tube, adding a mixed solvent consisting of water and methanol to the surface of the liquid in the test tube, and then adding a methanol solution containing 2,2′-bipyridine. The rare earth europium(III) probe material is obtained by diffusion. This rare earth europium(III) probe material can be applied to the fluorescence detection of o-nitroaniline, and has the advantages of low cost, strong signal, high sensitivity, and simple operation.

Description

Technical Field

[0001] This invention relates to the field of luminescent materials technology, and in particular to a rare earth europium (III) probe material, its preparation method, and its application as a fluorescence detection material. Background Technology

[0002] o-Nitroaniline is mainly used as a dye intermediate and in the synthesis of photographic anti-shadow agents. It is also used in the determination of trace iodides and the production of the pesticide carbendazim. It has high toxicity (more toxic than aniline). It can be absorbed through the skin and respiratory tract. It is a potent methemoglobin-forming agent; the resulting methemoglobin causes tissue hypoxia, leading to cyanosis and damage to the central nervous system, cardiovascular system, and other organs. Once o-nitroaniline is released into the environment, it causes pollution.

[0003] Numerous methods exist for the detection of o-nitroaniline, such as high-performance liquid chromatography (HPLC), gas chromatography (GC), gas chromatography-mass spectrometry (GC-MS), ion mobility spectrometry (IMS), and Raman spectroscopy. While these methods offer high accuracy, they are cumbersome to prepare, time-consuming, and require large instruments, thus reducing efficiency. Rare earth ions, with their unique 4f electron shell structure, possess unique photoluminescence properties in their complexes, exhibiting advantages such as high color purity, long fluorescence lifetime, and high quantum yield. The photoluminescence properties of rare earth complexes are now utilized in laser materials, fiber optic communications, and fluorescent probes. Furthermore, rare earth complexes can be used as probes in time-resolved biodetection technologies due to their long fluorescence lifetime. Therefore, developing a rare earth probe material with good detection performance and high efficiency for o-nitroaniline is a major trend. Summary of the Invention

[0004] One of the objectives of this invention is to provide a rare earth europium (III) probe material for detecting o-nitroaniline, achieving good detection effect and high detection efficiency.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: a rare earth europium(III) probe material, having the following chemical expression:

[0006] [Eu(C 24 H 16 O6) 1.5 (2,2′-bipy)(DMF)] n ; where 2,2′-bipy is a 2,2′-bipyridine molecule.

[0007] Furthermore, the crystallographic data of the rare-earth europium(III) probe material are as follows: triclinic crystal system, space group [missing information]. Unit cell parameters: α=69.966(5)°, β=88.999(5)°, γ=85.857(5)°, Dc = 1.361 g / cm³ 3 , Z=2, μ(MoKα)=1.366mm -1 , F(000)=994, R=0.0514, wR=0.1155.

[0008] In addition, the present invention also provides a method for preparing the above-mentioned rare earth europium(III) probe material, which mainly includes the following steps: adding 2,5-bis(4-methylbenzoyl)terephthalic acid to a container, adding a mixed solvent composed of water, N,N-dimethylformamide and methanol, heating in a water bath to dissolve it, then adding europium nitrate hexahydrate to this mixed solution, continuing to heat and stir, transferring the obtained mixed solution to a test tube, adding a mixed solvent composed of water and methanol to the surface of the liquid in the test tube, then adding a methanol solution containing 2,2′-bipyridine, covering the mouth of the test tube with a plastic film with small holes, letting it stand at room temperature, and after two weeks, colorless crystal products slowly precipitate out.

[0009] Preferably, the volume ratio of water, N,N-dimethylformamide, and methanol is 1:5:10.

[0010] More preferably, a mixed solvent consisting of water and methanol is added to the surface of the liquid in the test tube, wherein the volume ratio of water to methanol is 1:8 to 1:12.

[0011] The present invention also provides the application of the above-mentioned rare earth europium (III) probe material as a luminescent material.

[0012] Preferably, the luminescent material emits red fluorescence when excited by ultraviolet light.

[0013] Compared to existing technologies, the rare-earth europium(III) probe material provided by this invention emits strong red fluorescence under ultraviolet light excitation, thus enabling the detection of o-nitroaniline. This is because o-nitroaniline causes fluorescence quenching of the rare-earth europium(III) probe material. Fluorescence detection of o-nitroaniline can be achieved by observing the change in fluorescence intensity of the rare-earth europium(III) probe material at 617 nm after the addition of o-nitroaniline. This method for detecting o-nitroaniline offers advantages such as low cost, strong signal, high sensitivity, and ease of operation. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the crystal molecular structure of the rare earth europium(III) probe material of the present invention;

[0015] Figure 2A photograph of the rare earth europium(III) probe material of the present invention emitting red fluorescence under ultraviolet irradiation;

[0016] Figure 3 This is the solid-state fluorescence emission spectrum of the rare-earth europium(III) probe material of the present invention;

[0017] Figure 4 The rare earth europium(III) probe material of the present invention was prepared in o-nitroaniline solution (0-91 μmol·L⁻¹). -1 The emission spectrum in );

[0018] Figure 5 The effect of o-nitroaniline concentration on the fluorescence intensity ratio I0 / I of rare earth europium(III) probe material. Detailed Implementation

[0019] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to embodiments and accompanying drawings. The content mentioned in the embodiments is not intended to limit the present invention.

[0020] The method for preparing rare earth europium(III) probe materials includes the following steps: First, 0.100 mmol of 2,5-bis(4-methylbenzoyl)terephthalic acid is added to a round-bottom flask, followed by 16 ml of a mixed solvent consisting of water, N,N-dimethylformamide, and methanol (volume ratio 1:5:10). The mixture is heated in a water bath to dissolve the precipitate. Then, 0.072 mmol of europium nitrate hexahydrate is added to this mixed solution, and the mixture is heated and stirred continuously. The resulting mixed solution is then transferred to a glass test tube. 5.5 ml of a mixed solvent consisting of water and methanol (volume ratio 1:10) is added to the surface of the liquid in the test tube, followed by 4 ml of a methanol solution containing 0.166 mmol of 2,2′-bipyridine. The mouth of the test tube is covered with a perforated plastic wrap and left to stand at room temperature. After two weeks, colorless crystals slowly precipitate out.

[0021] The crystallographic data of this rare-earth europium(III) probe material are as follows: it belongs to the triclinic crystal system, space group [missing information]. Unit cell parameters: α=69.966(5)°, β=88.999(5)°, γ=85.857(5)°, Dc = 1.361 g / cm³ 3 , Z=2, μ(MoKα)=1.366mm -1 F(000) = 994, R = 0.0514, wR = 0.1155. The molecular structure of this rare earth europium(III) probe material is as follows: Figure 1 As shown.

[0022] The molecular structure of this rare-earth europium(III) probe material, including the main bond lengths and bond angles, is listed in Table 1. From the crystal structure... Figure 1 It is known that in the coordination polymer molecule, the 2,5-bis(4-methylbenzoyl) terephthalate ion acts as a bridging ligand, simultaneously coordinating with two adjacent europium(III) ions, forming a network structure. The central terbium(III) ion is in a nine-atom coordination environment, with six oxygen atoms from three 2,5-bis(4-methylbenzoyl) terephthalate ions, two nitrogen atoms from a 2,2′-bipyridine molecule, and one additional oxygen atom from an N,N-dimethylformamide (DMF) molecule. The Eu-O bond length is... Within the normal range.

[0023] Table 1. Main bond lengths of coordination polymers Bond angle (°)

[0024]

[0025] This rare-earth europium(III) probe material emits strong red fluorescence (e.g., when excited by 254nm ultraviolet light under a three-way ultraviolet lamp) Figure 2 (As shown); its fluorescence spectrum was measured using a fluorescence spectrophotometer. When the excitation wavelength was 356 nm, the coordination polymer exhibited two fluorescence emission peaks at 592 nm and 617 nm, corresponding to Eu and other wavelengths, respectively. 3+ of 5 D0→ 7 F1 and 5 D0→ 7 The electronic transition of F2 has the strongest emission peak at 617 nm (e.g., ...). Figure 3 (As shown).

[0026] Under the same testing conditions, the same amount of thoroughly ground europium(III) rare earth probe material was added to a solution with a concentration of 0.1 mol·L⁻¹. -1 The fluorescence emission spectra of the rare earth europium(III) probe material were detected in aqueous and blank solutions of o-nitroaniline. It was found that the fluorescence intensity of the rare earth europium(III) probe material was significantly quenched in the o-nitroaniline solution. This indicates that the material responds to o-nitroaniline and can be expected to be used as a probe for o-nitroaniline. - Fluorescent probes.

[0027] To further investigate the effect of o-nitroaniline on the fluorescence emission intensity of the rare-earth europium(III) probe material, under the same detection conditions, this rare-earth europium(III) probe material was added to o-nitroaniline solutions of different concentrations, and its fluorescence emission spectrum was measured. Figure 4As shown, the rare earth europium(III) probe material exhibits high fluorescence sensitivity to o-nitroaniline. Comparing the fluorescence peak intensity changes of this rare earth material at 617 nm, it was found that: (1) the fluorescence intensity of the rare earth europium(III) probe material at 617 nm gradually decreases with increasing o-nitroaniline concentration. (2) Let the fluorescence intensity of the rare earth europium(III) probe material in the blank solution be I0, and the fluorescence intensity in the o-nitroaniline solution be I. The ratio (I0 / I) is related to the concentration of the o-nitroaniline solution in the range of 0-91 μmol·L⁻¹. -1 A linear relationship is present within the range (e.g.) Figure 5 As shown), the linear equation is I0 / I = 0.9292 + 13973[2-Nitroaniline], R 2 =0.988.

[0028] This invention synthesizes a novel rare-earth europium(III) probe material using 2,2′-bipyridine, 2,5-bis(4-methylbenzoyl)-terephthalic acid, and europium nitrate as raw materials. This material possesses the following characteristics:

[0029] (1) The diffusion method is used for room temperature synthesis, which is energy-saving and environmentally friendly.

[0030] (2) The synthesis device is simple and easy to operate.

[0031] (3) The rare earth europium (III) probe material has good fluorescence intensity and monochromaticity. Under a three-way ultraviolet lamp, when the excitation wavelength is 254 nm, the material emits strong red fluorescence.

[0032] (5) Europium(III) rare-earth probe materials can be used to detect o-nitroaniline. The detection principle is mainly based on the fluorescence quenching of the rare-earth europium(III) probe material caused by o-nitroaniline. By measuring the change in fluorescence intensity of the rare-earth europium(III) probe material at 617 nm after the addition of o-nitroaniline, the fluorescence detection of o-nitroaniline can be achieved. The linear range of this method is 14-91 μmol / L, and the detection limit (3σ / s) is 1.941 μmol / L. This application has the advantages of low cost, strong signal, high sensitivity, and simple operation, saving tedious detection time.

[0033] To facilitate understanding by those skilled in the art of the improvements of this invention over the prior art, some of the accompanying drawings and descriptions have been simplified. The above embodiments are preferred implementations of this invention. In addition, this invention can be implemented in other ways. Any obvious substitutions without departing from the concept of this technical solution are within the protection scope of this invention.

Claims

1. A rare earth europium(III) probe material, characterized in that, It has the following chemical expression: [Eu(C 24 H 16 O6) 1.5 (2,2′-bipy)(DMF)] n ; where 2,2′-bipy is a 2,2′-bipyridine molecule; Furthermore, in the rare earth europium(III) probe material, 2,5-bis(4-methylbenzoyl) terephthalate acts as a bridging ligand, simultaneously coordinating with two adjacent europium(III) ions to form a network structure; the central europium(III) ion is in a nine-atom coordination environment, where six oxygen atoms come from three 2,5-bis(4-methylbenzoyl) terephthalate ions, two nitrogen atoms come from a 2,2′-bipyridine molecule, and another oxygen atom comes from an N,N-dimethylformamide molecule; The crystallographic data of rare earth europium(III) probe materials are as follows: Triclinic crystal system, space group Cell parameters: a = 9.5012(6) Å, b = 15.4237(8) Å, c = 17.4535(11) Å, α = 69.966(5) º, β = 88.999(5) º, γ = 85.857(5) º, V = 2396.6(3) Å 3 Dc = 1.361 g / cm³ 3 , Z = 2, μ(MoKα) = 1.366 mm -1 , F(000) = 994, R= 0.0514, wR = 0.1155.

2. A method for preparing the rare earth europium(III) probe material according to claim 1, characterized in that: 2,5-Di(4-methylbenzoyl)terephthalic acid was added to a container, followed by a mixed solvent consisting of water, N,N-dimethylformamide, and methanol. The mixture was heated in a water bath to dissolve the acid. Europium nitrate hexahydrate was then added to the mixed solution, and the mixture was heated and stirred. The resulting mixed solution was transferred to a test tube, and a mixed solvent consisting of water and methanol was added to the surface of the liquid in the test tube. A methanol solution containing 2,2′-bipyridine was then added. The rare earth europium(III) probe material was obtained by diffusion.

3. The method for preparing rare earth europium(III) probe material according to claim 2, characterized in that: The diffusion method involves covering the mouth of the test tube with a perforated plastic wrap, allowing it to stand at room temperature, and after two weeks, colorless crystals slowly precipitate out.

4. The method for preparing rare earth europium(III) probe material according to claim 2, characterized in that: The volume ratio of water, N,N-dimethylformamide, and methanol is 1:5:

10.

5. The method for preparing rare earth europium(III) probe material according to claim 2, characterized in that: Add a mixed solvent of water and methanol to the surface of the liquid in the test tube, with the volume ratio of water to methanol being 1:8 to 1:

12.

6. An application of the rare earth europium(III) probe material according to claim 1, characterized in that: Applications as luminescent materials.

7. The application of the rare earth europium(III) probe material according to claim 6, characterized in that: The luminescent material emits red fluorescence when excited by ultraviolet light.

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