阅读说明：本技术 一种稀土铽(iii)-有机框架配位聚合物及其制备方法和作为发光材料的应用 (Rare earth terbium (III) -organic framework coordination polymer, preparation method thereof and application thereof as luminescent material ) 是由 杨颖群 郑晓阳 庹路遥 郭小聪 于 2020-07-13 设计创作，主要内容包括：一种稀土铽(III)-有机框架配位聚合物及其制备方法和作为发光材料的应用,涉及稀土金属配合物技术领域,上述稀土铽(III)-有机框架配位聚合物荧光强度极强且单色性好,在三用紫外灯下,当激发波长为254nm时,能够发出强的绿色荧光,并在铁离子的探测方面表现出优异的选择性,当Fe<Sup>3+</Sup>浓度在0.00～1.25mmol.L<Sup>-1</Sup>的范围内时,上述稀土铽(III)-有机框架配位聚合物在水溶液中的荧光强度与其在铁离子溶液中的荧光强度的比值与Fe<Sup>3+</Sup>浓度呈现极强的线性关系,故该稀土铽(III)-有机框架配位聚合物可以作为荧光探针识别Fe<Sup>3+</Sup>,探测准确性高。(A rare earth terbium (III) -organic framework coordination polymer, a preparation method thereof and application thereof as a luminescent material relate to the technical field of rare earth metal complexes, the rare earth terbium (III) -organic framework coordination polymer has extremely strong fluorescence intensity and good monochromaticity, can emit strong green fluorescence under a three-purpose ultraviolet lamp when the excitation wavelength is 254nm, shows excellent selectivity in the aspect of iron ion detection, and when Fe is used 3+ The concentration is 0.00-1.25 mmol.L ‑1 In the range of (1), the ratio of the fluorescence intensity of the above-mentioned rare earth terbium (III) -organic framework coordination polymer in an aqueous solution to the fluorescence intensity thereof in an iron ion solution to Fe 3+ The concentration presents extremely strong linear relation, so the rare earth terbium (III) -organic framework coordination polymer can be used as a fluorescent probeIdentification of Fe 3+ And the detection accuracy is high.)

1. The rare earth terbium (III) -organic framework coordination polymer is characterized in that the crystal molecular structural formula of the rare earth terbium (III) -organic framework coordination polymer is as follows:

in the above formula, R is a water molecule.

2. The terbium (III) -organic framework coordination polymer according to claim 1, characterized in that it has crystallographic data of: monoclinic system, space group P2/n,

3. the method for preparing a rare earth terbium (III) -organic framework coordination polymer according to claim 1 or 2, comprising the steps of:

adding a proper amount of pyromellitic acid into a reaction container, adding a No. 1 mixed solvent consisting of methanol and water, stirring and dissolving, then adding a sodium hydroxide solution to adjust the pH value to 5-6, then adding a proper amount of terbium nitrate hexahydrate, stirring and dissolving at normal temperature to obtain a mixed solution, firstly adding a No. 2 mixed solvent consisting of water and methanol on the liquid surface of the mixed solution, then adding a methanol solution dissolved with 4,4' -bipyridyl, layering the solution, covering the reaction container under the condition of ensuring air permeability, standing for a period of time at room temperature, and obtaining a colorless crystal at the middle layer of the reaction container, namely the rare earth terbium (III) -organic framework coordination polymer.

4. The production method according to claim 3, characterized in that:

in the mixed solvent No. 1, the volume ratio of the methanol to the water is 1: 2; in the mixed solvent No. 2, the volume ratio of water to methanol is 1: 4.

5. the method of claim 4, wherein:

the ratio of the pyromellitic acid to the 1# mixed solvent is 12ml of 1# mixed solvent corresponding to each 0.33mmol of pyromellitic acid;

the molar ratio of the pyromellitic acid to the terbium nitrate hexahydrate to the added 4,4' -bipyridine is as follows: 3.3: 1: 2.5;

the volume ratio of the mixed solvent No. 1 to the mixed solvent No. 2 is 6: 1.

6. use of the rare earth terbium (III) -organic framework coordination polymer according to claim 1 or 2 as a light-emitting material.

7. The use of a terbium (III) -organic framework coordination polymer as defined in claim 1 or 2 in an iron ion fluorescent probe.

8. The terbium (III) organic framework coordination polymer as defined in claim 1 or 2, wherein Fe is contained in a solution containing iron ions³⁺The application of concentration detection is characterized in that: in Fe³⁺The concentration is not more than 1.25mmol.L^-1Using the rare earth terbium (III) -organic framework coordination polymer as an indicator in the solution to be detected, and obtaining Fe in the solution to be detected according to the following formula³⁺Concentration value:

I₀/I＝1.0105+450.75[Fe³⁺]；

in the above formula, I₀The fluorescence intensity of the rare earth terbium (III) -organic framework coordination polymer in a blank aqueous solution is shown, I is the fluorescence intensity of the rare earth terbium (III) -organic framework coordination polymer in an iron ion solution to be detected, [ Fe ]³⁺]Is Fe in the solution to be measured³⁺And (4) concentration.

Technical Field

The invention relates to the technical field of rare earth metal complexes, in particular to a rare earth terbium (III) -organic framework coordination polymer, a preparation method thereof and application thereof as a luminescent material.

Background

The rare earth ions have a special 4f electronic layer structure, and the complex has the unique photoluminescence performance and has the advantages of high luminescent color purity, narrow emission half-height width, long fluorescence service life and the like. The function of the photoluminescence of the rare earth complex can be seen in the fields of laser materials, optical fiber communication, fluorescent probes and the like. In order to enhance the fluorescence intensity of the complex, it is necessary to select a suitable sensitizer, and an organic ligand is generally used as the sensitizer, so that the sensitizer can effectively transfer energy to enable the rare earth ions to reach an emission state, and the commonly used organic ligand is beta-diketone, aromatic carboxylic acid and the like.

Chinese patent document CN107556486A discloses a rare earth organic framework material for iron ion fluorescence detection, which is a three-dimensional infinite network crystalline material with regular pore channels, and uses linear dicarboxylic acid with hydroxyl functional groups as an organic ligand, and the rare earth ions and carboxylic acid oxygen of the ligand form Ln-O one-dimensional infinite chains, and then form a three-dimensional porous structure through bridging the ligand. The rare earth organic framework material can be applied to the detection of the concentration of iron ions, and as shown in figure 3 in the literature, when the concentration of iron ions is in a concentration range of about 0-53 mu M, the fluorescence intensity and the concentration of iron ions are in a linear relationship, and ratio type fluorescence detection can be realized on the iron ions. In addition, the rare earth organic framework material in the above document is prepared by a hydrothermal method, the temperature is continuously above 120 ℃ in the reaction process, and the energy consumption is not low.

Chinese patent document CN108864158A discloses a tetranuclear rare earth terbium complex, which has better fluorescence intensity and monochromaticity, and in the document, the tetranuclear rare earth terbium complex is prepared by a diffusion method, and the synthesis process is carried out at normal temperature, thereby saving energy and protecting environment. However, the above documents do not disclose the results of the selective recognition test of iron ions by the tetranuclear rare earth terbium complex, and the fluorescence intensity of the tetranuclear rare earth terbium complex also has room for improvement.

Disclosure of Invention

One of the purposes of the invention is to provide a rare earth terbium (III) -organic framework coordination polymer with a chain structure, which has high fluorescence intensity and can realize ratio type fluorescence detection on iron ions in a larger concentration range.

In order to achieve the above object, the present invention provides a terbium (III) -organic framework coordination polymer, wherein the crystal molecular structural formula of the terbium (III) -organic framework coordination polymer is:

in the above formula, R is a water molecule.

Wherein, the crystallography data of the rare earth terbium (III) coordination polymer are as follows: the crystal belongs to monoclinic system, space group P2/n, α＝90.00°,β＝109.552(8)°,γ＝90.00°,

Dc＝7.86g/cm³, F(000)＝1560,S＝1.192。

in addition, the invention also provides a method for preparing the rare earth terbium (III) -organic framework coordination polymer, which comprises the following steps:

adding a proper amount of pyromellitic acid into a reaction container, adding a No. 1 mixed solvent consisting of methanol and water, stirring and dissolving, then adding a sodium hydroxide solution to adjust the pH value to 5-6, then adding a proper amount of terbium nitrate hexahydrate, stirring and dissolving at normal temperature to obtain a mixed solution, firstly adding a No. 2 mixed solvent consisting of water and methanol on the liquid surface of the mixed solution, then adding a methanol solution dissolved with 4,4' -bipyridyl, layering the solution, covering the reaction container under the condition of ensuring air permeability, standing for a period of time at room temperature, and obtaining a colorless crystal at the middle layer of the reaction container, namely the rare earth terbium (III) -organic framework coordination polymer.

Wherein, in the mixed solvent No. 1, the volume ratio of the methanol to the water is 1: 2; in the mixed solvent No. 2, the volume ratio of water to methanol is 1: 4.

wherein the ratio of the pyromellitic acid to the 1# mixed solvent is 12ml of the 1# mixed solvent corresponding to each 0.33mmol of pyromellitic acid;

the molar ratio of the pyromellitic acid to the terbium nitrate hexahydrate to the added 4,4' -bipyridine is as follows: 3.3: 1: 2.5;

the volume ratio of the mixed solvent No. 1 to the mixed solvent No. 2 is 6: 1.

the rare earth terbium (III) -organic framework coordination polymer can be applied as a luminescent material.

In addition, the rare earth terbium (III) -organic framework coordination polymer can also be applied to iron ion fluorescent probes.

Finally, the rare earth terbium (III) -organic framework coordination polymer can also be used for the Fe in iron ion-containing solution³⁺Concentration detection, in particular in Fe³⁺The concentration is not more than 1.25mmol.L^-1The rare earth terbium (III) -organic framework coordination polymer is used as an indicator in the solution to be detected, and Fe in the solution to be detected is obtained according to the following formula³⁺Concentration value:

I₀/I＝1.0105+450.75[Fe³⁺]；

in the above formula, I₀The fluorescence intensity of the rare earth terbium (III) -organic framework coordination polymer in a blank aqueous solution is shown, I is the fluorescence intensity of the rare earth terbium (III) -organic framework coordination polymer in an iron ion solution to be detected, [ Fe ]³⁺]Is Fe in the solution to be measured³⁺And (4) concentration.

The rare earth terbium (III) -organic framework coordination polymer is fluorescentThe luminous intensity and the monochromaticity are good, and under a three-purpose ultraviolet lamp, when the excitation wavelength is 254nm, the fluorescent lamp can emit extremely strong green fluorescence. And the rare earth terbium (III) -organic framework coordination polymer shows excellent selectivity on detection of iron ions when being used as Fe³⁺The concentration is 0.00-1.25 mmol.L^-1In the range of (1), the ratio of the fluorescence intensity of the above-mentioned rare earth terbium (III) -organic framework coordination polymer in an iron ion solution to the fluorescence intensity thereof in an aqueous solution to Fe³⁺The concentration presents extremely strong linear relation, so the rare earth terbium (III) -organic framework coordination polymer can be used as a fluorescent probe to identify Fe³⁺Compared with two products in the background art (documents CN107556486A and CN108864158A), the rare earth terbium (III) -organic framework coordination polymer can realize ratio type fluorescence detection on iron ions in a larger concentration range, and has high detection accuracy. Different from the rare earth organic framework material in CN107556486A in the literature which adopts a hydrothermal method, the invention adopts a diffusion method to synthesize the rare earth terbium (III) -organic framework coordination polymer at normal temperature, thereby being more energy-saving and environment-friendly. Meanwhile, the synthesis device used by the invention is simpler and the operation is simpler. Compared with the tetranuclear rare earth terbium (III) complex in the document CN108864158A, the rare earth terbium (III) -organic framework coordination polymer prepared by the invention has higher fluorescence intensity.

Description of the drawings:

FIG. 1 is a molecular structural diagram of a rare earth terbium (III) -organic framework coordination polymer prepared in the example;

FIG. 2 is a photograph of a terbium (III) -organic framework coordination polymer emitting strong green fluorescence under a three-way ultraviolet lamp at an excitation wavelength of 254 nm;

FIG. 3 is a solid fluorescence emission spectrum of a rare earth terbium (III) -organic framework coordination polymer at room temperature;

FIG. 4 is a graph showing the effect of different metal ions on the fluorescence emission spectra of a rare earth terbium (III) -organic framework coordination polymer;

FIG. 5 shows the coordination polymer of rare earth terbium (III) in Fe³⁺The concentration is 0.00-1.25 mmol.L^-1Emission spectra in different solutions; the insert in the upper left corner of the graph is the fluorescence intensity ratio I₀I and Fe³⁺A graph of concentration dependence;

FIG. 6 is a graph showing the effect of different metal ions on the fluorescence emission spectrum of a tetranuclear rare earth terbium complex;

FIG. 7 shows the four-core rare earth terbium complex in Fe³⁺The concentration is 0.00-1.0 mmol.L^-1Emission spectra in different solutions; the insert in the upper right corner of the graph is the fluorescence intensity ratio I₀I and Fe³⁺A graph of concentration dependence;

FIG. 8 shows the solid fluorescence emission spectra of terbium (III) -organic framework coordination polymer (a) and tetranuclear terbium (b) under the same test conditions.

Detailed Description

In order to facilitate the understanding of those skilled in the art, the present invention will be further described with reference to the following examples, which are not intended to limit the present invention. It should be noted that the following examples are carried out in the laboratory, and it should be understood by those skilled in the art that the amounts of the components given in the examples are merely representative of the proportioning relationship between the components, and are not specifically limited.

1. Synthesis of rare earth terbium (III) -organic frame coordination polymer.

0.33mmol of pyromellitic acid is added into a round-bottom flask, the mixture is dissolved by 12ml of mixed solvent of methanol and water (volume ratio is 1: 2), sodium hydroxide solution is added to adjust the pH value of the solution to be 5-6, then 0.10mmol of terbium nitrate hexahydrate is added, stirring is continued, and the mixed solution is transferred into a glass test tube. 2ml of a mixed solvent composed of water and methanol (volume ratio: 1: 4) was added to the liquid surface in the test tube, and then a methanol solution containing 0.25mmol of 4,4' -bipyridine dissolved therein (i.e., the amount of 4,4' -bipyridine added was 0.25mmol, which is understood to mean that 0.25mmol of 4,4' -bipyridine was dissolved in an appropriate amount of methanol and then the whole was added to the test tube) was added, and the solution in the test tube was separated into layers. And finally, covering the opening of the test tube with the small-hole preservative film, standing for a period of time at room temperature, and obtaining a colorless crystal product in the middle layer of the test tube. The colorless crystal product is the rare earth terbium (III) -organic framework coordination polymer. It is noted that during the preparation, the pH of the solutionThe choice of the value and the solvent mixture is very important, and an inappropriate pH value and solvent mixture will result in no formation of the desired product. The crystallographic data of the above-mentioned terbium (III) -organic framework coordination polymer are as follows: the crystal belongs to monoclinic system, space group P2/n,

α＝90.00°, β＝109.552(8)°,γ＝90.00°,Dc＝7.86g/cm³f (000) ═ 1560, S ═ 1.192. Elemental analysis: elemental analysis: theoretical value (%): c39.90, H3.04, N4.23; found (%): c39.82, H3.03, N4.22. (2) IR (KBr, cm)^-1)：1695(vs)， 1560(vs)，1516(s),1396(s)，816(s)，548(w)。

2. Crystal structure of rare earth terbium (III) -organic framework coordination polymer.

The molecular structure of the above-mentioned terbium (III) -organic framework coordination polymer is shown in FIG. 1, and the main bond lengths and bond angles are shown in Table 1. As can be seen from fig. 1, in the rare earth terbium (III) -organic framework coordination polymer molecule, pyromellitic acid radical is used as a bridging ligand to coordinate with two adjacent terbium (III) ions at the same time, and the whole molecule forms a chain structure. The central terbium (III) ion is in a nine coordinate environment, with the terbium (III) ion coordinated to the 4 oxygen atoms of the two pyromellitic acid groups and to the five water molecules. Meanwhile, in the complex molecule, there are water molecules which are not coordinated and 4,4' -bipyridine molecules. The bond length of Tb-O is

Range, within normal range.

TABLE 1 major bond length of the complexes

Angle of and key (°)

3. And (3) testing the performance of the rare earth terbium (III) -organic framework coordination polymer.

3.1 As shown in figure 2, under a three-way ultraviolet lamp, when the complex is excited by ultraviolet light with the wavelength of 254nm, the complex emits extremely strong green fluorescence; the fluorescence spectrum is measured by using a fluorescence spectrophotometer, and as shown in figure 3, when the excitation wavelength is 325nm, the complex has four fluorescence emission peaks at 491, 546, 586 and 622nm, which correspond to Tb respectively³⁺Is/are as follows⁵D₄→⁷F₆、⁵D₄→⁷F₅、⁵D₄→⁷F₄And⁵D₄→⁷F₃wherein the fluorescence intensity at 546nm is strongest.

3.2 adding the fully ground rare earth terbium (III) -organic framework coordination polymer and barium sulfate powder into a high polymer material adhesive, uniformly dispersing by ultrasonic, and uniformly fixing the mixture on a glass slide.

The glass slides were each added at a concentration of 0.01mol.L^-1Different metal ion (Ag)⁺、 Al³⁺、Ba²⁺、Ca²⁺、Ca²⁺、Cd²⁺、Co²⁺、Cr³⁺、Cu²⁺、Fe²⁺、Hg²⁺、 K⁺、Mg²⁺、Mn²⁺、Na⁺、Ni²⁺、Pb²⁺、Zn²⁺、Fe³⁺) In the solution, the fluorescence emission spectrum of the rare earth terbium (III) -organic framework coordination polymer is detected, and the detection result is shown in figure 4. As can be seen from FIG. 4, the fluorescence emission spectra of the terbium (III) rare earth-organic framework coordination polymers in the respective solutions have substantially the same peak shape, but differ in intensity to a different extent. Comparison of Tb in rare earth terbium (III) -organic framework coordination polymer molecules³⁺At 546nm (⁵D₄→⁷F₅) Change in fluorescence emission intensity: when in Ag⁺、Al³⁺、Ba²⁺、Ca²⁺、Ca²⁺、Cd²⁺、Co²⁺、 Cr³⁺、Cu²⁺、Fe²⁺、Hg²⁺、K⁺、Mg²⁺、Mn²⁺、Na⁺、Ni²⁺、Pb²⁺And Zn²⁺The fluorescence emission intensity of the rare earth terbium (III) -organic framework coordination polymer is hardly changed in the solution; when in Fe³⁺The fluorescence intensity of the foregoing terbium (III) -organic framework coordination polymer is almost quenched when in solution, which may be Fe³⁺The addition of (a) inhibits the transfer of energy from the ligand to the rare earth ion. Therefore, the rare earth terbium (III) -organic framework coordination polymer can efficiently detect Fe³⁺Can be used as Fe³⁺The fluorescent probe of (1).

To further study Fe³⁺Effect on fluorescence emission intensity of rare earth Terbium (III) -organic framework coordination Polymer the foregoing slides were added to different concentrations of Fe³⁺In solution, under the same detection conditions, the presence of Fe is recorded³⁺Fluorescence emission spectrum of rare earth terbium (III) -organic framework coordination polymer in solution (see fig. 5). As shown in FIG. 5, the rare earth terbium (III) -organic framework coordination polymer pair Fe³⁺Has high fluorescence sensitivity with Fe³⁺Increase in concentration, Tb³⁺The fluorescence intensity at 546nm gradually decreased. Setting the fluorescence intensity of the rare earth terbium (III) -organic framework coordination polymer in a blank aqueous solution as I₀In Fe³⁺The fluorescence intensity in the solution is I, the ratio thereof (I)₀I) and Fe³⁺The concentration is 0.00-1.25 mmol.L^-1Shows extremely strong linear relation in the range (the insert in the upper left corner of FIG. 5), and the linear equation is I₀/I＝1.0105+450.75[Fe³⁺]R2 ═ 0.9958. Wherein [ Fe ]³⁺]Is Fe in the solution to be measured³⁺And (4) concentration.

4. Tetranuclear rare earth terbium complex pair Fe³⁺Selective identification test of (2).

The tetranuclear rare earth terbium complex is prepared according to the method in the document CN108864158A, and the molecular structure of the tetranuclear rare earth terbium complex is shown in figure 1 in the document CN 108864158A. And adding the fully ground four-core rare earth terbium complex and barium sulfate powder into a high polymer material adhesive, uniformly dispersing by ultrasonic, and uniformly fixing on a glass slide.

4.1 the slides were each added to a concentration of 0.01mol.L^-1Different metal ion (Ag)⁺、Al³⁺、Ba²⁺、Ca²⁺、Ca²⁺、Cd²⁺、Co²⁺、Cr³⁺、Cu²⁺、Fe²⁺、 Hg²⁺、K⁺、Mg²⁺、Mn²⁺、Na⁺、Ni²⁺、Pb²⁺、Zn²⁺、Fe³⁺) In the solution, the fluorescence emission spectrum of the tetranuclear rare earth terbium complex is detected, and the detection result is shown in figure 6. As can be seen from FIG. 6, the fluorescence intensity of the tetranuclear rare earth terbium complex is in Fe³⁺Almost quenched in the solution, and the fluorescence intensity change is not obvious in other metal ion solutions, which shows that the tetranuclear rare earth terbium complex can be used for Fe³⁺Identified and highly selective, can be used as Fe³⁺The fluorescent probe of (1).

4.2 to further study Fe³⁺The influence on the fluorescence emission intensity of the tetranuclear rare earth terbium complex is realized by adding the glass slide into Fe with different concentrations³⁺In solution, under the same detection conditions, the presence of Fe is recorded³⁺Fluorescence emission spectrum of tetranuclear rare earth terbium complex in solution (see FIG. 7), as shown in FIG. 7, tetranuclear rare earth terbium complex for Fe³⁺Has high fluorescence sensitivity with Fe³⁺Increase in concentration, Tb³⁺The fluorescence intensity at 545nm gradually decreased. Setting the fluorescence intensity of the tetranuclear rare earth terbium complex in a blank aqueous solution as I₀In Fe³⁺The fluorescence intensity in the solution is I, the ratio thereof (I)₀I) and Fe³⁺The concentration is 0.0-1.0 mmol.L^-1Within the range satisfying the Sterm-Volmer (SV) equation: i is₀/I＝1+K_svC, and presents a linear relationship (see inset in the upper right corner of FIG. 7), the linear equation being I₀/I＝1.0+712.82[Fe³⁺]，R2＝0.9974。

From the above test results, it can be seen that the terbium (III) organic framework coordination polymer provided by the present invention can realize ratio-type fluorescence detection of iron ions in a larger concentration range compared with the tetranuclear terbium (tb) complex in document CN 108864158A.

5. And (3) performing comparative test on the fluorescence intensity of the rare earth terbium (III) -organic framework coordination polymer and the tetranuclear rare earth terbium complex.

The fluorescence emission spectrum of the rare earth terbium (III) -organic framework coordination polymer (a in FIG. 8) and the fluorescence emission spectrum of the tetranuclear rare earth terbium complex in the document CN108864158A (b in FIG. 8) were measured using a fluorescence spectrophotometer model F-7000 under the same test conditions. As can be seen from fig. 8: at 545nm, the fluorescence intensity of the rare earth terbium (III) organic framework coordination polymer is obviously stronger than that of the tetranuclear rare earth terbium complex (the fluorescence intensity of the rare earth terbium (III) -organic framework coordination polymer is about 1.8 times of that of the tetranuclear rare earth terbium complex).

In summary, from the above test results of the rare earth terbium (III) -organic framework coordination polymer, the comparative test results of the rare earth terbium (III) -organic framework coordination polymer and the tetranuclear rare earth terbium complex, and the preparation process of the rare earth terbium (III) -organic framework coordination polymer, it can be determined that: the terbium (III) -organic framework coordination polymer prepared by the embodiment has good fluorescence intensity and monochromaticity, and can emit extremely strong green fluorescence under a three-way ultraviolet lamp when the excitation wavelength is 254 nm. And the rare earth terbium (III) -organic framework coordination polymer shows excellent selectivity on detection of iron ions when being used as Fe³⁺The concentration is 0.00-1.25 mmol.L^-1In the range of (1), the ratio of the fluorescence intensity of the above-mentioned rare earth terbium (III) -organic framework coordination polymer in an iron ion solution to the fluorescence intensity thereof in an aqueous solution to Fe³⁺The concentration presents extremely strong linear relation, so the rare earth terbium (III) -organic framework coordination polymer can be used as a fluorescent probe to identify Fe³⁺Compared with two products in the background art (documents CN107556486A and CN108864158A), the rare earth terbium (III) -organic framework coordination polymer can realize ratio type fluorescence detection on iron ions in a larger concentration range, and has high detection accuracy. In addition, compared with the rare earth organic framework material in the document CN107556486A, the rare earth terbium (III) -organic framework coordination polymer synthesized by the diffusion method at normal temperature in the above examples is more energy-saving and environment-friendly. Meanwhile, the synthesis device used in the embodiment is simpler and the operation is simpler. Compared with the tetranuclear rare earth terbium complex in the document CN108864158AThe terbium (III) -organic framework coordination polymer prepared in the above example has significantly higher fluorescence intensity at 545 nm.

The above embodiments are preferred implementations of the present invention, and the present invention can be implemented in other ways without departing from the spirit of the present invention.

Finally, it should be emphasized that some of the descriptions of the present invention have been simplified to facilitate the understanding of the improvements of the present invention over the prior art by those of ordinary skill in the art, and that other elements have been omitted from this document for the sake of clarity, and those skilled in the art will recognize that these omitted elements may also constitute the content of the present invention.