阅读说明：本技术 一种高效红光铕配合物发光材料及其制备方法和应用 (High-efficiency red-light europium complex luminescent material and preparation method and application thereof ) 是由 李夏 罗李林 崔瑞方 于 2020-04-01 设计创作，主要内容包括：本发明涉及一种高效红光铕配合物发光材料及其制备方法及在对抗生素荧光传感方面的应用。该红光铕配合物[Eu(DPBA)(Phen)-(2)]·H-(2)O(H-(3)DPBA＝2-(3’,4’-二羧基苯氧基)苯甲酸,Phen＝1,10-菲罗啉)通过水热法制备而成,属于三斜晶系,Pī空间群,晶胞参数该高效红光铕配合物中Eu～(3+)的配位数为8,其中每一个Eu～(3+)分别与3个DPBA配体的4个氧原子和2个Phen配体的4个氮原子配位。配体DPBA与金属中心采用μ-(1):η～(1)η～(0)/μ-(2):η～(1)η～(1)的配位模式配位,形成一维结构。该高效红光铕配合物固体粉末量子产率高达86％。在352nm激发下可实现对几种抗生素的检测。本发明合成简单,成本低廉。(The invention relates to a high-efficiency red europium complex luminescent material, a preparation method thereof and application thereof in the aspect of antibiotic fluorescence sensing. The red europium complex [ Eu (DPBA) (Phen) 2 ]·H 2 O(H 3 DPBA ═ 2- (3',4' -dicarboxyphenoxy) benzoic acid, Phen ═ 1, 10-phenanthroline) was prepared by hydrothermal method, belonging to triclinic system, P ī space group, unit cell parameter Eu in the high-efficiency red-light europium complex 3+ Has a coordination number of 8, wherein each Eu 3+ With 4 respective DPBA ligandsOne oxygen atom is coordinated to 4 nitrogen atoms of 2 Phen ligands. Ligand DPBA and metal center are in mu form 1 :η 1 η 0 /μ 2 :η 1 η 1 The coordination mode of (A) to form a one-dimensional structure. The quantum yield of the high-efficiency red europium complex solid powder is as high as 86%. Detection of several antibiotics can be achieved under 352nm excitation. The invention has simple synthesis and low cost.)

1. A high-efficiency red-light europium complex luminescent material is characterized in that the molecular formula of the europium complex is [ Eu (DPBA) (Phen)₂]·H₂O(H₃DPBA ═ 2- (3',4' -dicarboxyphenoxy) benzoic acid, Phen ═ 1, 10-phenanthroline).

2. The red-emitting europium complex phosphor of claim 1, wherein the europium complex belongs to the triclinic system, P ī space group, cell parameters

3. The efficient red-emitting europium complex luminescent material of claim 1 or 2, wherein the europium complex comprises Eu in a crystallographically independent unit cell unit as analyzed by single crystal data³⁺Ions, 1 DPBA ligand, 2 Phen ligands and 1 free water molecule that is not coordinated.

4. The red-emitting europium complex luminescent material of claim 1, wherein the central metal of the europium complex is coordinated with 4 oxygen atoms of DPBA and 4 nitrogen atoms of 2 Phen to form an eight-coordinated one-dimensional metal-organic coordination polymer.

5. The red-emitting europium complex luminescent material of claim 1 or 2, wherein the europium complex has a high thermal stability as shown by the thermogravimetric curve, and the skeleton does not begin to collapse until about 390 ℃.

6. The red-emitting europium complex luminescent material of claim 1 or 2, wherein the europium complex [ Eu (DPBA) (Phen) ] is activated by 352nm UV light as determined by fluorescence spectroscopy₂]·H₂The O solid presents a stronger red fluorescence emission peak at 616nm, and the quantum yield of the solid powder is as high as 86%.

7. A method for preparing a red-light europium complex luminescent material is characterized in that Eu (NO) is used in the method₃)₃·6H₂O，H₃DPBA and Phen are used as raw materials, distilled water and sodium hydroxide solution are used as solvents, and the preparation method is adopted.

8. Method according to claim 7, characterized in that it comprises the following steps:

the method comprises the following steps: eu (NO)₃)₃·6H₂O，H₃Adding DPBA, Phen into a reaction kettle with a polytetrafluoroethylene inner container, wherein Eu (NO)₃)₃·6H₂O，H₃The mass ratio of DPBA and Phen is 1:1:1.5, 10ml of distilled water and 200 mul of sodium hydroxide solution with the concentration of 1mol/L are added as solvent;

step two: placing the reaction kettle in the first step in an electric heating constant-temperature air-blowing drying oven, heating to 120 ℃, continuously heating for 72 hours, and then slowly cooling to room temperature at a cooling rate of 3 ℃/h;

filtering and drying the product obtained in the second step to obtain a white powdery solid, namely a target product [ Eu (DPBA) (Phen)₂]·H₂O。

9. A method for applying the red-light europium complex luminescent material of claim 1, wherein the europium complex can be used for preparing red fluorescent materials and realizing the detection of nitroantibiotics in water bodies, or detecting anions and cations, organic small molecules and drug molecules in biological and environmental systems.

Technical Field

The invention relates to a high-efficiency red europium complex luminescent material, a preparation method thereof, and application of the luminescent material in the aspects of selective detection of antibiotics and the like, belonging to the field of luminescent materials.

Background

Rare earth ions have become very important multifunctional luminescent materials in the last two decades due to their unique luminescent properties (long emission lifetime, large stokes shift, high color purity). However, since the f-f transition of rare earth ions is forbidden, the rare earth ions have very weak absorption of light in the ultraviolet region, so that the light emission intensity of the rare earth ions is very weak. To solve this problem, an organic ligand having strong absorbance in the ultraviolet region is generally introduced, and energy is transferred to the center of the rare earth ion through the organic ligand, thereby sensitizing the rare earth ion to luminescence (antenna effect). In general, an "antenna" is generally required to have a high molar extinction coefficient in the ultraviolet region while also having high efficiency in intersystem crossing and energy transfer processes. Thus, the choice of organic ligand and the structure of the complex directly influence the luminescence of the complex. For the reasons mentioned above, aromatic or heteroaromatic compounds of the pi-conjugated system are the first candidates. In the past research, the efficient fluorescent europium complex has important application in the fields of luminescence, display, illumination, biological imaging, detection and the like, and a large number of materials with high luminous efficiency are developed up to now. However, the carboxylic acid highly efficient luminescent europium complexes reported in the literature are still few so far. In recent research, the inventor finds a carboxylic acid ligand capable of effectively sensitizing europium metal and realizing high-efficiency luminescence. 2- (3',4' -Dicarboxyphenoxy) benzoic acid (H)₃DPBA) is an organic ligand with a conjugated system and a semi-rigid structure, and has better plane rigidity; meanwhile, 1, 10-phenanthroline (Phen) with strong chelating and coordinating capabilities also has a large conjugated system. The two ligands can jointly regulate and control the structure of the complex, so that the ligands can more effectively transfer energy to the center of the rare earth ion, and further the fluorescence property is enhanced.

Due to the unique fluorescence property of the efficient red-light europium complex, the efficient red-light europium complex has wide application in fluorescence detection, and can realize the detection of anions and cations, organic molecules, drug molecules and the like. Antibiotics, a commonly used drug in animal husbandry and aquaculture, play an important role in treating animal diseases and promoting the growth of livestock. However, serious abuse and residues of antibiotics have also caused contamination of water and soil resources. More seriously, these residual antibiotics may eventually be ingested by humans, causing acute or chronic poisoning. With the increasing public health and environmental protection concerns, the need for detecting and removing environmental pollutants is more and more urgent. Therefore, in the fields of analytical technology and environmental science, it is important to find a method for rapidly detecting anions and cations, small organic molecules, drugs and the like.

At present, methods for detecting and analyzing the content of antibiotics in water mainly include liquid chromatography-mass spectrometry, ultraviolet detection liquid chromatography, capillary electrophoresis, surface enhanced raman spectroscopy and fluorescence. Although the traditional detection technology has high sensitivity, the traditional detection technology is limited due to the fact that instruments are expensive and not easy to carry. Compared with other detection methods, the fluorescence method has the advantages of simple operation, high sensitivity, good selectivity and the like. Therefore, it is increasingly receiving attention and being widely studied.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a preparation method and application of a high-efficiency red europium complex. In the invention, H is selected₃DPBA and Phen have large conjugated systems, and organic ligands with strong absorbance in an ultraviolet region are synthesized into an europium complex with high luminous efficiency and good thermal stability by a hydrothermal method. The molecular formula is [ Eu (DPBA) (Phen)₂]·H₂O, the new substance is simple to synthesize and stable in property, white powder emits red fluorescence under the excitation of ultraviolet light under the natural light, and the quantum yield of solid powder is as high as 86%. Can be used for preparing red fluorescent materials and detecting anions and cations, organic micromolecules, drug molecules and the like in biological and environmental systems.

In order to realize the purpose of the invention, the method is realized by the following technical scheme:

efficient red light europium preparationThe preparation scheme of the compound is as follows: with Eu (NO)₃)₃·6H₂O，H₃DPBA and Phen are used as raw materials, distilled water and sodium hydroxide solution are used as solvents, and the preparation method is adopted. The method specifically comprises the following steps:

(1) eu (NO)₃)₃·6H₂O，H₃Adding DPBA, Phen into a reaction kettle with a polytetrafluoroethylene inner container, wherein Eu (NO)₃)₃·6H₂O，H₃The mass ratio of DPBA, Phen was 1:1:1.5, 10 milliliters (ml) of distilled water and 200 microliters (μ L) of sodium hydroxide solution at a concentration of 1 mole/liter (mol/L) were added as solvents.

And (2) placing the reaction kettle in the step (1) in an electric heating constant temperature air blast drying oven, heating to 120 ℃ (DEG C) for 72 hours, and then slowly cooling to room temperature at a cooling rate of 3 ℃/hour (DEG C/h).

Filtering and drying the product obtained in the step (2) to obtain a white powdery solid, namely a target product [ Eu (DPBA) (Phen)₂]·H₂O。

The efficient red light europium complex prepared by the method can be used for preparing red fluorescent materials and detecting nitroantibiotics in water. And can also be used for detecting anions and cations, organic small molecules, drug molecules and the like in biological and environmental systems.

Compared with the prior art, the invention has the following beneficial effects:

(1) according to the technical scheme provided by the invention, the invention provides the high-efficiency red europium complex which is prepared by a simple one-step hydrothermal method, and the molecule of the high-efficiency red europium complex is [ Eu (DPBA) (Phen)₂]·H₂And O. Analysis of single crystal data shows that the asymmetric unit cell contains a crystallographically independent Eu³⁺Ions, 1 DPBA ligand, 2 Phen ligands and 1 free water molecule that is not coordinated. The thermogravimetric curve shows that the high-efficiency red light europium complex has high thermal stability, and the framework does not collapse until about 390 ℃.

(2) The high-efficiency red light prepared by the inventionThe europium complex is colorless under natural light and bright red light under 365 nanometer (nm) ultraviolet light. As shown by fluorescence spectrum test, the europium complex [ Eu (DPBA) (Phen) at the maximum excitation wavelength of 352nm₂]·H₂The O solid presents a stronger red fluorescence emission peak at 616nm, which is a characteristic emission peak of europium ions. The quantum yield of the solid powder is as high as 86%.

(3) By adopting the preparation method, the yield of the prepared high-efficiency red europium complex is about 60 percent. Meanwhile, the high-efficiency red europium complex provided by the invention has positive influence on environmental pollution treatment, preparation of novel red fluorescent materials and development and utilization of rare earth elements. Can be used for detecting anions and cations, organic small molecules, drug molecules and the like in biological and environmental systems.

Drawings

FIGS. 1(a) and 1(b) show europium complexes [ Eu (DPBA) (Phen) according to the invention₂]·H₂The crystal structure of O; wherein FIG. 1(a) is a diagram showing the Eu (III) coordination environment, and FIG. 1(b) is a one-dimensional structural diagram;

FIG. 2 is an X-ray powder diffraction pattern (abscissa-angle; ordinate-diffraction intensity) of a europium complex of the present invention;

FIG. 3 is a thermogravimetric plot of europium complexes of the invention (air atmosphere; abscissa-temperature; ordinate-percent residue);

FIG. 4 is a fluorescence spectrum of a europium complex of the present invention (abscissa-wavelength; ordinate-relative fluorescence intensity; Ex is excitation wavelength); wherein, the illustration is as follows: the excitation spectrum (Em is emission wavelength) of the europium complex of the invention.

FIG. 5 is a graph showing the change in fluorescence intensity of europium complexes of the present invention in the presence of different types of antibiotic solutions (abscissa-different types of antibiotics; ordinate-relative fluorescence intensity);

FIGS. 6(a) -6(c) are graphs showing the fluorescence intensity of europium compounds of the present invention (abscissa-wavelength; ordinate-relative fluorescence intensity) as a function of the amount of antibiotic added thereto, when excited at 352 nm; wherein, the illustration is as follows: linear regression equation obtained from antibiotic titration curve (abscissa-antibiotic concentration; ordinate- (I)₀/I)-1；(I₀Fluorescence intensity when no antibiotic was added, I is fluorescence intensity after antibiotic addition)).

Detailed Description

The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.

In order to more clearly show the technical solutions and the technical effects provided by the present invention, the method of the present invention is described in detail below with reference to specific embodiments. In the invention, the final product is subjected to X-ray single crystal diffraction test and analyzed to obtain an accurate crystal structure; and performing a series of characterization on the final product, such as elemental analysis, X-ray powder diffraction, thermogravimetry, fluorescence and the like.

Overall, the highly efficient red europium complex [ Eu (DPBA) (Phen) ]₂]·H₂O(H₃DPBA ═ 2- (3',4' -dicarboxyphenoxy) benzoic acid, Phen ═ 1, 10-phenanthroline) was prepared by hydrothermal method, belonging to triclinic system, P ī space group, unit cell parameter Eu in the europium complex³⁺Has a coordination number of 8, wherein each Eu³⁺Coordinated to 4 oxygen atoms of 3 DPBA ligands and 4 nitrogen atoms of 2 Phen ligands, respectively. Ligand DPBA and metal center are in mu form₁:η¹η⁰/μ₂:η¹η¹The coordination mode of (A) to form a one-dimensional structure. The quantum yield of the high-efficiency red europium complex solid powder is as high as 86%. Detection of several antibiotics can be achieved under 352nm excitation.

Example 1.

Firstly, preparation of the high-efficiency red light europium complex

The efficient red europium complex is prepared by the following steps: eu (NO)₃)₃·6H₂O(0.1mmol)，H₃DPBA (0.1mmol) and Phen (0.15mmol) are put into a 25ml reaction kettle, 10ml deionized water is added,200 mu L of NaOH solution with the concentration of 1mol/L is screwed down outside the metal of the reaction kettle, then the mixture is placed in an electric heating constant temperature blast drying oven, the temperature is increased to 120 ℃ and is kept for 72 hours, the temperature is reduced to room temperature at the speed of 3 ℃/h, the mixture is filtered, washed by distilled water, and after drying, white powdery solid is obtained, and the yield is about 60 percent.

Selecting high-quality, suitable-size and high-transparency crystals, placing on Bruker Smart APE XII CCD type X-ray single crystal diffractometer, and monochromating with graphite monochromator to obtain Cu-KalphaThe radiation light source scans the crystal and collects diffraction points, the crystal structure is solved by a direct method by adopting an olex2 program, the coordinate of a hydrogen atom is determined by a theoretical hydrogenation method, and the hydrogen atom and the non-hydrogen atom are corrected by a full matrix least square method by respectively adopting isotropic and anisotropic temperature factors. The main crystallographic data are shown in table 1.

TABLE 1 Primary crystallographic data

The data were analyzed to obtain the crystal structure (fig. 1(a) and 1 (b)). The structure analysis result shows that 4 oxygen atoms of central metal europium and DPBA and 4 nitrogen atoms of 2 Phen are coordinated to form an eight-coordinated one-dimensional metal-organic coordination polymer. The peaks of the PXRD test pattern can be well matched with the diffraction peaks of the crystal structure fitting pattern (software Mercury), indicating that the obtained crystals are target products and the purity of the sample is high (fig. 2).

The main symmetrical operations are:¹1-X,-Y,1-Z；²1+X,1+Y,+Z；³-1+X,-1+Y,+Z

the target product has a chemical formula of C₃₉H₂₇N₄O₉Eu, molecular mass 847.6, elemental analysis theoretical value: c (55.21%), H (2.71%), N (6.61%), actual value: c (55.23%), H (2.69%), N (6.58%).

Thermogravimetric data analysis of the obtained complex product in an air atmosphere shows that the complex product mainly has two weight losses, the free water molecules are lost at about 100 ℃ for the first time, and the weight loss percentage is 2.21 percent (the theoretical weight loss ratio is 2.13 percent); the skeleton begins to decompose after 390 ℃, which shows that the high-efficiency red europium complex has higher thermal stability (figure 3).

Solid state fluorescence test shows that the europium complex [ Eu (DPBA) (Phen)₂]·H₂The maximum excitation wavelength of O is 352 nm. With the wavelength as the excitation wavelength, the europium complex has fluorescence emission peaks at 593nm and 616nm, which are characteristic emission peaks of europium ions (fig. 4), and the fluorescence quantum yield of the solid powder is as high as 86%.

This example was repeated several times, and based on the amount of Eu (III), the complex [ Eu (DPBA) (Phen) was calculated₂]·H₂The O product yield was about 60%. The crystal diffraction data obtained by repeating the experiment was consistent with the data obtained by fitting, the crystal structure obtained was unchanged and the product was purer (fig. 2), which shows that the operation repeatability of example 1 was very high.

Secondly, the high-efficiency red europium complex detects the nitro-containing antibiotics

3 mg (mg) of the europium complex powder prepared in example 1 of the present invention was weighed, sufficiently ground, dissolved in 3 mL (mL) of water, and dispersed in amoxicillin, azithromycin, ornidazole, sulfadimidine, sulfamethoxazole, sulfadiazine, sulfathiazole thiamphenicol, metronidazole, roxithromycin, metronidazole, penicillin (each at a concentration of 1X 10)^-3mol/L), sonicated for 30 minutes, and aged for three days. Obtaining a fluorescence intensity diagram under the excitation of 352nm wavelength (figure 5);

the fluorescence intensity of the europium complex was almost completely quenched after addition of the ornidazole, metronidazole and metronidazole antibiotic solutions (fig. 5). Therefore, the high-efficiency red europium complex prepared by the invention can detect the antibiotic containing the nitro group in the aqueous solution within a certain range. And other substances such as anions and cations, organic small molecules and the like in the environmental pollutants can also be detected.

Respectively titrating three antibiotics of ornidazole, metronidazole and metronidazole by a fluorescence titration method (the concentration is 1 multiplied by 10)^-3mol/L) and the titration range is 0-720 mu L, the mixture is shaken up after each dripping, and the fluorescence emission spectrum of the complex is detected. The europium complex has detection limit of 7.4 × 10 for ornidazole^-6mol/L, the detection limit of metronidazole is 1.2 multiplied by 10^-7mol/L, the detection limit of the metronidazole is 3.1 multiplied by 10^-6mol/L (FIGS. 6(a) -6 (c)).

The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention.