Luminescent crystal material, preparation method thereof and application of luminescent crystal material in luminescence quenching detection of Hg < 2 + >

Abstract

The invention discloses a luminescent crystal material and a preparation method and application thereof in luminescence quenching detection of Hg < 2 + >, a luminescent metal-organic framework crystal material [Cd (L) (OBBA)] n is prepared based on a new AIE type functional ligand 4, 4 '-((9H-fluorene-9-yl) methylene) bis (1H-pyrazole), the method is simple, the synthetic route is simple and easy to control, the product yield can reach 39.3%, and the luminescent crystal material is suitable for industrial production. Compared with the prior art, the material can be used for detecting Hg < 2 + > in a luminescence quenching manner, has extremely high sensitivity, has a quenching constant of 4.36 * 10 < 4 > M <-1 > and a detection limit of 8.25 * 10 <-7 > M in the luminescence quenching detection of water phase Hg < 2 + >, and has a wide application prospect.

Description

Technical Field

[0001] The present invention belongs to the technical field of luminescent detection functional materials, and specifically relates to a luminescent crystal material and a preparation method thereof and a method for detecting Hg by luminescent quenching. 2+ Application in. Background Art

[0002] Mercury ions (Hg 2+ ) is a common toxic heavy metal that poses a serious threat to the environment and human health. 2+ Detection methods such as atomic absorption spectroscopy and inductively coupled plasma mass spectrometry are accurate, but the equipment is expensive and the operation is complicated. 2+ Detection materials have become a research hotspot.

[0003] In recent years, luminescent materials have become popular in Hg 2+ Especially the materials based on the principle of luminescence quenching, through Hg 2+ Interaction with the material causes a change in luminescence intensity, thus enabling detection. However, existing materials still have shortcomings in sensitivity, selectivity, stability and preparation process. Summary of the Invention

[0004] The purpose of this section is to summarize some aspects of the embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the abstract and title of this application to avoid obscuring the purpose of this section, the abstract and the title of the invention, and such simplifications or omissions should not be used to limit the scope of the present invention.

[0005] In view of the above problems and / or the problems existing in the prior art, the present invention is proposed.

[0006] Therefore, the purpose of the present invention is to overcome the deficiencies in the prior art and provide a luminescent crystal material.

[0007] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0008] (i) The chemical formula is [Cd(L)(OBBA)] n , wherein L is 4,4'-((9H-fluoren-9-yl)methylene)bis(1H-pyrazole) ligand, OBBA 2- is a 4,4-diphenylether dicarboxylate anion ligand, and n is an arbitrary value;

[0009] (ii) A two-dimensional planar structure is formed by the coordination of cadmium ions with 4,4'-((9H-fluoren-9-yl)methylene)bis(1H-pyrazole) ligands and 4,4-diphenylether dicarboxylate ion ligands.

[0010] As a preferred embodiment of the luminescent crystal material of the present invention, the molecular formula of the luminescent crystal material is C 34 H 22 CdN4O5; crystal system is triclinic; space group is P-1; unit cell parameters are α=94.499(4)°, β=100.786(5)°, γ=91.621(4)°, Z=2.

[0011] Another object of the present invention is to provide a method for preparing a luminescent crystal material.

[0012] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0013] 5 / 2 hydrated cadmium chloride, 4,4'-((9H-fluoren-9-yl)methylene)bis(1H-pyrazole), and 4,4-diphenylether dicarboxylic acid are added to a mixed solvent of water and methanol and stirred to obtain a mixed solution;

[0014] The mixed solution is placed in a sealed reactor and heated for reaction, then slowly cooled to room temperature. The product is filtered, washed, and dried to obtain the luminescent crystal material [Cd(L)(OBBA)] n .

[0015] As a preferred embodiment of the method for preparing the luminescent crystal material of the present invention, the molar ratio of the 2 / 5 hydrated cadmium chloride, 4,4'-((9H-fluoren-9-yl)methylene)bis(1H-pyrazole), and 4,4-diphenyl ether dicarboxylic acid is 1:0.5~2:0.5~2.

[0016] As a preferred solution of the method for preparing the luminescent crystal material of the present invention, the volume ratio of water to methanol in the mixed solvent is 1:0.5-2.

[0017] As a preferred embodiment of the method for preparing the luminescent crystal material of the present invention, the volume of the mixed solvent required for each 0.1 mmol of 5 / 2 hydrated cadmium chloride is 4 to 12 mL.

[0018] As a preferred solution of the method for preparing the luminescent crystal material of the present invention, the reaction time of the heating reaction is 48 to 72 hours.

[0019] As a preferred solution of the method for preparing the luminescent crystal material of the present invention, the cooling rate of slowly cooling to room temperature is 2-5°C / h.

[0020] Another object of the present invention is to provide a luminescent crystal material for detecting Hg by luminescence quenching. 2+ The luminescent crystal material is used for luminescence quenching detection of Hg 2+, which can detect Hg in water phase by luminescence 2+ The quenching constant is 4.36×10 4 M -1 , the detection limit was 8.25×10 -7 M.

[0021] Beneficial effects of the present invention:

[0022] The present invention synthesizes a luminescent crystal material [Cd(L)(OBBA)] based on the new AIE type organic ligand 4,4'-((9H-fluoren-9-yl)methylene)bis(1H-pyrazole) n The synthesis method is extremely simple, the route is mild and easy to control, and the obtained material [Cd(L)(OBBA)] n Can be used for luminescence quenching detection of Hg in aqueous phase 2+ Compared with the existing technology, the use of this crystal material for detection is simple and reliable, and the luminescence quenching detection of Hg in water phase 2+ The quenching constant is as high as 4.36×10 4 M -1 , the detection limit is as low as 8.25×10 -7 M, currently the most sensitive method for detecting Hg 2+ The luminescent crystal material has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be derived from these drawings without inventive effort. Among them:

[0024] Figure 1 This is the NMR spectrum of the ligand 4,4'-((9H-fluoren-9-yl)methylene)bis(1H-pyrazole) used in the present invention.

[0025] Figure 2 This is the core crystal structure of the ligand 4,4'-((9H-fluoren-9-yl)methylene)bis(1H-pyrazole) used in the present invention.

[0026] Figure 3 The crystalline material prepared by the present invention [Cd(L)(OBBA)] n Two-dimensional crystal structure diagram.

[0027] Figure 4 The crystalline material prepared by the present invention [Cd(L)(OBBA)] n X-ray diffraction pattern of powder.

[0028] Figure 5 This is a diagram showing the aggregation-induced emission effect of the new functional ligand 4,4'-((9H-fluoren-9-yl)methylene)bis(1H-pyrazole) used in the present invention.

[0029] Figure 6 The crystalline material prepared by the present invention [Cd(L)(OBBA)] n Excitation and emission spectra of aqueous suspension (0.1 mg / mL).

[0030] Figure 7 The luminescent crystal material [Cd(L)(OBBA)] prepared in the present invention n The luminescence intensity change curve of different volumes of mercury ion aqueous solution (2mmol / L) was added to the water suspension.

[0031] Figure 8 The crystalline material prepared by the present invention [Cd(L)(OBBA)] n Quenching constant curve for detecting mercury ions.

[0032] Figure 9 The crystalline material prepared by the present invention [Cd(L)(OBBA)] n Detection limit curve for mercury ion detection. DETAILED DESCRIPTION

[0033] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the embodiments of the specification.

[0034] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0035] Secondly, the term "one embodiment" or "embodiment" herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in various places throughout this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive of other embodiments.

[0036] Unless otherwise specified, the raw materials used in the present invention are all commercially available analytically pure materials in the art.

[0037] The yield of the present invention is calculated based on the ligand L [4,4'-((9H-fluoren-9-yl)methylene)bis(1H-pyrazole)], and the calculation formula is m (实际晶体) / m (L完全反应)

[0038] Example 1

[0039] This embodiment provides a method for preparing a luminescent crystal material, specifically:

[0040] 1) Synthesis of 4,4'-((9H-fluoren-9-yl)methylene)bis(1H-pyrazole)

[0041] 9-Fluorenone (5.4 g, 30.0 mmol), carbon tetrabromide (19.9 g, 60.0 mmol), and triphenylphosphine (26.3 g, 100.0 mmol) were dissolved in 250 mL of toluene, stirred, and heated at 40°C for 24 h. After filtration, the mixture was vacuum distilled and anhydrous ethanol was added to allow recrystallization overnight to obtain bright pale yellow crystals of 9-(dibromomethylene)-9H-fluorene in an 80% yield.

[0042] 9-(Dibromomethylene)-9H-fluorene (2 g, 6 mmol), 4-pyrazoleboronic acid (3.36 g, 30.0 mmol), 9-dibromoethylene-fluorene (338 mg, 1.00 mmol), anhydrous sodium carbonate (3.5 g, 33.00 mmol), and tetrakis(triphenylphosphine)palladium (0.5 g, 0.43 mmol) were added to 250 mL of a mixed solvent of 1,4-dioxane / water (V dioxane:V water = 4:1), and the mixture was heated to 120°C under a nitrogen atmosphere for 24 h.

[0043] After extraction, the organic component was purified by flash column chromatography using ethyl acetate / petroleum ether as the mobile phase to obtain the pure product ligand L (0.83 g, 2.67 mmol). Figure 1 The NMR spectrum of the ligand 4,4'-((9H-fluoren-9-yl)methylene)bis(1H-pyrazole) prepared in this step is as follows: Figure 2 The figure is a crystal structure diagram of the ligand 4,4'-((9H-fluoren-9-yl)methylene)bis(1H-pyrazole), indicating that the ligand was successfully synthesized. The ligand 4,4'-((9H-fluoren-9-yl)methylene)bis(1H-pyrazole) used in the following examples were synthesized according to this step.

[0044] 2) 0.05 mmol of 5 / 2 hydrated cadmium chloride, 0.025 mmol of 4,4'-((9H-fluoren-9-yl)methylene)bis(1H-pyrazole), and 0.05 mmol of 4,4-diphenyl ether dicarboxylic acid were added to 3 mL of a mixed solvent (V water:V methanol = 1:1) and stirred to obtain a mixed solution;

[0045] 3) The mixture was placed in a sealed reactor and heated to 140°C for 48 hours. The temperature was slowly cooled to room temperature at a rate of 2°C / h. The product was filtered and washed with deionized water and methanol to obtain the crystalline material [Cd(L)(OBBA)] n .

[0046] The structure of the prepared crystal material was analyzed using Bruker's ApexII single crystal diffractometer, and the results are shown in Table 1.

[0047] Table 1

[0048]

[0049]

[0050] As shown in Table 1, the extremely sensitive luminescence quenching detection of Hg 2+ The molecular formula of the luminescent crystal material is C 34 H 22 CdN4O5; crystal system is triclinic; space group is P-1; unit cell parameters are β=100.786(5)°, γ=91.621(4)°, Z=2.

[0051] Figure 3 The crystalline material [Cd(L)(OBBA)] was prepared for this example. n The two-dimensional crystal structure of (hydrogen atoms are omitted), Figure 4 The powder X-ray diffraction pattern is compared with the theoretically calculated X-ray diffraction pattern, which is basically consistent with the theoretically calculated X-ray diffraction pattern, indicating that the crystal material prepared by the present invention has a very high purity.

[0052] Figure 5 This is a fluorescence image of the new functional ligand 4,4'-((9H-fluoren-9-yl)methylene)bis(1H-pyrazole) used in this example in a mixed solution of DMF and water.

[0053] Figure 6 The crystalline material [Cd(L)(OBBA)] prepared in Example 1 of the present invention n The fluorescence properties in aqueous suspension showed that the maximum excitation wavelength for detecting mercury ions was 310 nm and the maximum emission wavelength was 470 nm.

[0054] Figure 7 To 2.5 mL of Example 1 crystalline material [Cd(L)(OBBA)] at a concentration of 0.1 mg / mL n The luminescence intensity change curve of the aqueous suspension of the crystal material is shown in FIG1. ​​The luminescence intensity of the aqueous suspension of the crystal material is measured at an excitation wavelength of 310 nm when different volumes of mercury ion aqueous solution with a concentration of 2 mmol / L are added to the aqueous suspension. It can be seen that the luminescence intensity of the suspension is gradually quenched as the amount of mercury ions gradually increases.

[0055] Figure 8 、 Figure 9The crystal materials of this embodiment are [Cd(L)(OBBA)] n Detection of Hg in aqueous phase 2+ The quenching constant curve and detection limit curve of the material showed that the luminescence quenching detection of Hg in water phase 2+ The quenching constant is 4.36×10 4 M -1 , the detection limit was 8.25×10 -7 M, indicating that the detection material provided by the present invention can detect Hg in water phase by extremely sensitive luminescence quenching 2+ .

[0056] Example 2

[0057] 1) 0.025 mmol of 5 / 2 hydrated cadmium chloride, 0.025 mmol of 4,4'-((9H-fluoren-9-yl)methylene)bis(1H-pyrazole), and 0.05 mmol of 4,4-diphenyl ether dicarboxylic acid were added to 3 mL of a mixed solvent (V water:V methanol = 1:1) and stirred to obtain a mixed solution;

[0058] 2) The mixture was placed in a sealed reactor and heated to 150°C for 48 hours. The temperature was slowly cooled to room temperature at a rate of 3°C / h. The product was filtered and washed with deionized water and methanol to obtain the crystalline material [Cd(L)(OBBA)] n .

[0059] Example 3

[0060] 1) 0.05 mmol of 5 / 2 hydrated cadmium chloride, 0.025 mmol of 4,4'-((9H-fluoren-9-yl)methylene)bis(1H-pyrazole), and 0.025 mmol of 4,4-diphenyl ether dicarboxylic acid were added to 3 mL of a mixed solvent (V water:V methanol = 1:1) and stirred to obtain a mixed solution;

[0061] 2) The mixture was placed in a sealed reactor and heated to 150°C for 72 hours. The temperature was slowly cooled to room temperature at a rate of 2°C / h. The product was filtered and washed with deionized water and methanol to obtain the crystalline material [Cd(L)(OBBA)] n .

[0062] Example 4

[0063] 1) 0.05 mmol of 5 / 2 hydrated cadmium chloride, 0.025 mmol of 4,4'-((9H-fluoren-9-yl)methylene)bis(1H-pyrazole), and 0.05 mmol of 4,4-diphenyl ether dicarboxylic acid were added to 3 mL of a mixed solvent (V water:V methanol = 1:1) and stirred to obtain a mixed solution;

[0064] 2) The mixture was placed in a sealed reactor and heated to 130°C for 72 hours. The temperature was slowly cooled to room temperature at a rate of 2°C / h. The product was filtered and washed with deionized water and methanol to obtain the crystalline material [Cd(L)(OBBA)] n .

[0065] Example 5

[0066] 1) 0.025 mmol of 5 / 2 hydrated cadmium chloride, 0.025 mmol of 4,4'-((9H-fluoren-9-yl)methylene)bis(1H-pyrazole), and 0.025 mmol of 4,4-diphenyl ether dicarboxylic acid were added to 1.5 mL of a mixed solvent (V water:V methanol = 1:1) and stirred to obtain a mixed solution;

[0067] 2) The mixture was placed in a sealed reactor and heated to 150°C for 72 hours. The temperature was slowly cooled to room temperature at a rate of 2°C / h. The product was filtered and washed with deionized water and methanol to obtain the crystalline material [Cd(L)(OBBA)] n .

[0068] Example 6

[0069] 1) 0.05 mmol of 5 / 2 hydrated cadmium chloride, 0.025 mmol of 4,4'-((9H-fluoren-9-yl)methylene)bis(1H-pyrazole), and 0.025 mmol of 4,4-diphenyl ether dicarboxylic acid were added to 6 mL of a mixed solvent (V water:V methanol = 1:1) and stirred to obtain a mixed solution;

[0070] 2) The mixture was placed in a sealed reactor and heated to 150°C for 72 hours. The temperature was slowly cooled to room temperature at a rate of 3°C / h. The product was filtered and washed with deionized water and methanol to obtain the crystalline material [Cd(L)(OBBA)] n .

[0071] Example 7

[0072] 1) 0.025 mmol of 5 / 2 hydrated cadmium chloride, 0.025 mmol of 4,4'-((9H-fluoren-9-yl)methylene)bis(1H-pyrazole), and 0.025 mmol of 4,4-diphenyl ether dicarboxylic acid were added to 3 mL of a mixed solvent (V water:V methanol = 1:2) and stirred to obtain a mixed solution;

[0073] 2) The mixture was placed in a sealed reactor and heated to 120°C for 72 hours. The temperature was slowly cooled to room temperature at a rate of 2°C / h. The product was filtered and washed with deionized water and methanol to obtain the crystalline material [Cd(L)(OBBA)] n .

[0074] Example 8

[0075] 1) 0.05 mmol of 5 / 2 hydrated cadmium chloride, 0.025 mmol of 4,4'-((9H-fluoren-9-yl)methylene)bis(1H-pyrazole), and 0.05 mmol of 4,4-diphenyl ether dicarboxylic acid were added to 6 mL of a mixed solvent (V water:V methanol = 1:2) and stirred to obtain a mixed solution;

[0076] 2) The mixture was placed in a sealed reactor and heated to 150°C for 48 hours. The temperature was slowly cooled to room temperature at a rate of 5°C / h. The product was filtered and washed with deionized water and methanol to obtain the crystalline material [Cd(L)(OBBA)] n .

[0077] Example 9

[0078] 1) 0.05 mmol of 5 / 2 hydrated cadmium chloride, 0.025 mmol of 4,4'-((9H-fluoren-9-yl)methylene)bis(1H-pyrazole), and 0.05 mmol of 4,4-diphenyl ether dicarboxylic acid were added to 3 mL of a mixed solvent (V water:V methanol = 1:0.5) and stirred to obtain a mixed solution;

[0079] 2) The mixture was placed in a sealed reactor and heated to 150°C for 48 hours. The temperature was slowly cooled to room temperature at a rate of 2°C / h. The product was filtered and washed with deionized water and methanol to obtain the crystalline material [Cd(L)(OBBA)] n .

[0080] The yields of the crystalline materials prepared in Examples 1 to 9 were calculated, and the results are shown in Table 2.

[0081] Table 2

[0082]

[0083]

[0084] It can be seen from Table 2 that the luminescent crystal materials can be prepared by adopting the scheme of the present invention, and the yield is significantly affected by adjusting the preparation conditions.

[0085] Comparative Example 1

[0086] The difference between this comparative example and Example 1 is that the mixed solvent in step 1) is adjusted (V water: V methanol = 1:3), and the remaining steps and processes are referred to Example 1. As a result, the solution is clear and no crystals are generated, indicating that the preparation is unsuccessful.

[0087] Comparative Example 2

[0088] The difference between this comparative example and Example 1 is that the mixed solvent in step 1) is adjusted to only water, and the processes in the remaining steps are the same as those in Example 1. As a result, the solution is turbid, with a large amount of precipitation and no crystals generated, and the preparation is unsuccessful.

[0089] Comparative Example 3

[0090] This comparative example differs from Example 1 in that the molar ratio of 5 / 2 hydrated cadmium chloride, 4,4'-((9H-fluoren-9-yl)methylene)bis(1H-pyrazole), and 4,4-diphenyl ether dicarboxylic acid in step 1) is adjusted to 3:1:3, and the remaining steps and processes are referred to Example 1. As a result, the solution is turbid, no crystals are generated, and the preparation is unsuccessful.

[0091] Comparative Example 4

[0092] The difference between this comparative example and Example 1 is that, except for adjusting the cooling rate in step 2) to 1°C / h, the processes of the remaining steps are all referred to Example 1. As a result, the yield is not significantly improved, the experimental process is slow, and unnecessary resources are wasted.

[0093] Comparative Example 5

[0094] The difference between this comparative example and Example 1 is that the heating reaction temperature in step 2) is adjusted to 100° C., and the remaining steps are all based on Example 1. As a result, the crystal growth is incomplete and the quality is poor, and subsequent testing cannot be performed.

[0095] Comparative Example 6

[0096] This comparative example differs from Example 1 in that the ligand in step 2) is adjusted to 4,4'-((9H-fluoren-9-yl)methylene)dipyrimidine, step 1) is omitted, and the remaining steps and processes are all based on Example 1. As a result, a relatively clear solution is obtained with essentially no crystal precipitation, and the quality is poor, making subsequent testing impossible.

[0097] It can be seen from Comparative Examples 1 to 6 that the luminescent crystal material of the present application can not be successfully prepared under any conditions.

[0098] Comparative Example 7

[0099] The difference between this comparative example and Example 1 is that the 4,4-diphenyl ether dicarboxylic acid in step 2) is adjusted to 1,4-naphthalene dicarboxylic acid, the 5 / 2 hydrated cadmium chloride is adjusted to cadmium nitrate tetrahydrate, step 1) is omitted, and the remaining steps are referred to Example 1 to obtain the crystal of this comparative example. After testing, the crystal has a high affinity for Hg 2+ No detection effect.

[0100] Comparative Example 8

[0101] The difference between this comparative example and Example 1 is that the 4,4-diphenyl ether dicarboxylic acid in step 1) is adjusted to 9-anthracenecarboxylic acid, step 1) is omitted, and the remaining steps are referred to Example 1 to obtain the crystal of this comparative example. After testing, the crystal has a high affinity for Hg 2+ No detection effect.

[0102] In summary, the present invention provides a novel AIE-type 4,4'-((9H-fluoren-9-yl)methylene)bis(1H-pyrazole) functional organic ligand capable of extremely sensitive luminescence quenching detection of Hg in aqueous phase. 2+ The preparation method and product of the luminescent metal-organic framework crystal material are simple and easy to control, and the product yield can reach 39.3%, which is suitable for industrial production and promotion. Compared with the existing technology, the crystal material can detect Hg by luminescence quenching for the first time. 2+ , extremely high sensitivity, luminescence quenching detection of Hg in aqueous phase 2+ The quenching constant is 4.36×10 4 M -1 , the detection limit is as low as 8.25×10 -7 M, has broad application prospects.

[0103] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A luminescent crystal material, characterized in that: (i) The chemical formula is [Cd(L)(OBBA)] n , wherein L is 4,4'-((9H-fluoren-9-yl)methylene)bis(1H-pyrazole) ligand, OBBA 2- is a 4,4-diphenylether dicarboxylate anion ligand, and n is an arbitrary value; (ii) A two-dimensional planar structure is formed by the coordination of cadmium ions with 4,4'-((9H-fluoren-9-yl)methylene)bis(1H-pyrazole) ligands and 4,4-diphenylether dicarboxylate ion ligands.

2. The luminescent crystal material according to claim 1, wherein: The molecular formula of the luminescent crystal material is C 34 H 22 CdN4O5; crystal system is triclinic; space group is P-1; unit cell parameters are α=94.499(4)°, β=100.786(5)°, γ=91.621(4)°, Z=2.

3. The method for preparing a luminescent crystal material according to any one of claims 1 or 2, wherein: include, 5 / 2 hydrated cadmium chloride, 4,4'-((9H-fluoren-9-yl)methylene)bis(1H-pyrazole), and 4,4-diphenylether dicarboxylic acid are added to a mixed solvent of water and methanol and stirred to obtain a mixed solution; The mixed solution is placed in a sealed reactor and heated for reaction, then slowly cooled to room temperature. The product is filtered, washed, and dried to obtain the luminescent crystal material [Cd(L)(OBBA)] n .

4. The method for preparing a luminescent crystal material according to claim 3, wherein: The molar ratio of the 2 / 5 hydrated cadmium chloride, 4,4'-((9H-fluoren-9-yl)methylene)bis(1H-pyrazole), and 4,4-diphenyl ether dicarboxylic acid is 1:0.5-2:0.5-2.

5. The method for preparing a luminescent crystal material according to claim 3, wherein: The volume ratio of water to methanol in the mixed solvent is 1:0.5-2.

6. The method for preparing a luminescent crystal material according to any one of claims 4 or 5, wherein: The volume of the mixed solvent required for each 0.1 mmol of 5 / 2 hydrated cadmium chloride is 4 to 12 mL.

7. The method for preparing a luminescent crystal material according to claim 4, wherein: The reaction temperature of the heating reaction is 120-180°C.

8. The method for preparing a luminescent crystal material according to claim 7, wherein: The reaction time of the heating reaction is 48 to 72 hours.

9. The method for preparing a luminescent crystal material according to claim 3, wherein: The cooling rate of slowly cooling to room temperature is 2-5°C / h.

10. The luminescent crystal material according to any one of claims 1 or 2 is used to detect Hg by luminescence quenching. 2+ The application is characterized by: The luminescent crystal material is used for detecting Hg by luminescence quenching 2+ , which can detect Hg in water phase by luminescence 2+ The quenching constant is 4.36×10 4 M -1 , the detection limit was 8.25×10 -7 M.

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