A fluorescent silver-platinum nanocluster material, a preparation method and application thereof

Abstract

The application belongs to the cross field of nanomaterials and coordination chemistry, and specifically discloses a fluorescent silver-platinum nanocluster material, a preparation method and application as a mercury ion detection probe in mercury ion detection. 162 H 156 Ag 14 Cl4P 12 Pt, which is abbreviated as Ag 14 Pt(Dppp)6Cl4, belongs to a monoclinic system; a space group is P21 / c, alpha=90 degrees, beta=112.279(4) degrees, gamma=90 degrees, and a molecular weight is 4321.57 Da. The preparation method provided by the application does not need a complex process flow, and synthesis is carried out at normal temperature and pressure, the operation steps are simple, and raw materials are easy to obtain. The fluorescent silver-platinum nanocluster material has high stability, an electrochemical energy gap is as high as 1.53 V, can be stored for at least 30 days under normal temperature and pressure conditions, shows excellent fluorescence selectivity and sensitivity to mercury ions, and has good application prospect.

Description

TECHNICAL FIELD

[0001] The present application belongs to the cross field of nanomaterials and coordination chemistry, and particularly relates to a fluorescent silver-platinum nanocluster material, a preparation method thereof and application thereof in mercury ion detection. BACKGROUND

[0002] Mercury ions have been listed as a key pollution control pollutant by various national agencies and international organizations due to their extremely high toxicity and difficulty in being biodegraded. Mercury ions can be accumulated in organisms through the food chain and eventually enter the human body, causing the human body to have decreased immunity, damage to the immune system function, and thus increase the incidence of various epidemics and chronic diseases. Designing new materials and developing easy-to-use analysis techniques for real-time and rapid detection of mercury ions in real samples is a prerequisite for protecting the natural environment and preventing human diseases. So far, various analysis techniques such as inductively coupled plasma mass spectrometry, high-performance liquid chromatography, gas chromatography, atomic absorption spectrometry, atomic fluorescence spectrometry, X-ray fluorescence spectrometry, and electrochemical analysis have been widely used in the detection of heavy metal ions. However, these analysis techniques usually rely on bulky and costly precision equipment, and also require complex sample pretreatment steps, which greatly limits their application potential in rapid on-site detection. As ion probes, fluorescent nanoclusters have attracted widespread attention from researchers due to their simple operation, no need for complex sample pretreatment, low cost, and small sample damage during detection.

[0003] However, fluorescent nanoclusters are prone to aggregation into nanoparticles due to their small particle size and high surface free energy, which often leads to a significant decrease in cluster stability and fluorescence intensity. Currently, there are still few reports on fluorescent nanoclusters with precise single-crystal structure, high stability, and the ability to achieve specific detection of mercury ions. SUMMARY

[0004] The purpose of the present application is to overcome the limitations of the prior art and provide a fluorescent silver-platinum nanocluster material with high stability, an electrochemical energy gap as high as 1.53V, and the ability to be stored for at least 30 days under normal temperature and pressure conditions, excellent fluorescence selectivity and sensitivity to mercury ions, and good application prospects.

[0005] One of the purposes of the present application is to provide a fluorescent silver-platinum nanocluster material with the chemical formula C 162 H 156 Ag 14 Cl4P 12 Pt, abbreviated as Ag 14 Pt(Dppp)6Cl4, which belongs to the monoclinic system, and the space group is P21 / c, α = 90°, β = 112.279(4)°, γ = 90°, Molecular weight is 4321.57 Da; wherein Dppp is 1,3-bis(diphenylphosphino)propane, the structural formula is as follows:

[0006]

[0007] Further improvement of the fluorescent silver platinum nanocluster material:

[0008] Preferably, the structure of the fluorescent silver platinum nanocluster material is composed of 14 Ag atoms, one Pt atom, 6 dppp organic ligands and 4 halogen Cl ligands.

[0009] The second object of the present application is to provide a preparation method of the fluorescent silver platinum nanocluster material as claimed in any one of the above, comprising the following steps:

[0010] S1, silver trifluoromethanesulfonate is added to a mixed solvent of dichloromethane and methanol, stirred to fully dissolve, then platinum salt and 1,3-bis(diphenylphosphino)propane are added, and the stirring is continued to obtain a uniform mixed solution;

[0011] S2, an aqueous solution of sodium borohydride is added to the mixed solution, and the reaction is carried out at room temperature for 12-20 h to obtain a suspension, an excess of n-hexane is added to the suspension, the precipitate is collected by centrifugation and washed again with an excess of n-hexane and centrifuged to obtain a crude product;

[0012] S3, the crude product is dissolved with methanol, then at room temperature, the formation of crystals is induced by gas-phase diffusion of diethyl ether into the solution, the crystal product is collected and naturally air-dried to prepare the fluorescent silver platinum nanocluster material.

[0013] Further improvement of the preparation method of the above fluorescent silver platinum nanocluster material:

[0014] Preferably, the molar mass ratio of silver trifluoromethanesulfonate, platinum salt, 1,3-bis(diphenylphosphino)propane and sodium borohydride is 1:(0.1-0.5):(1-2):(0.4-2.5).

[0015] Preferably, the platinum salt in step S1 is chloroplatinic acid or platinum nitrate.

[0016] Preferably, in step S1, dichloromethane and methanol are mixed in a volume ratio of 9:1 to form a mixed solvent, and the addition amount of silver trifluoromethanesulfonate in the mixed solvent is 1-2 mg / ml.

[0017] Preferably, in step S2, the concentration of the aqueous solution of sodium borohydride is 0.8-5.4 mg / ml.

[0018] Preferably, in step S2, the precipitate is collected by centrifugation at a speed of 8500-10000 rpm for 40-60 seconds.

[0019] The second object of the present application is to provide an application of the fluorescent silver-platinum nanocluster material in detecting mercury ions.

[0020] As a further improvement of the application of the fluorescent silver-platinum nanocluster material in detecting mercury ions:

[0021] Preferably, under the excitation of 430 nm wavelength, the mercury ion standard solution is added into the solution containing the fluorescent silver-platinum nanocluster material at a volume ratio of 1:10, the concentration of the mercury ion standard solution is 1-10 μM, the concentration of the solution containing the fluorescent silver-platinum nanocluster material is 10-18 μM, and the emission peak intensity of the solution at 592 nm is greatly reduced.

[0022] The present application has the following advantages compared with the prior art:

[0023] 1) The preparation method of the present application provides a reference for the synthesis technology of fluorescent nanoclusters. The preparation method provided by the present application has the advantages of simple operation process, mild reaction conditions, low cost, no need for calcination, and no need for complex process flow. The synthesis is carried out at normal temperature and pressure, the operation steps are simple, and the raw materials are easy to obtain. The fluorescent silver-platinum nanocluster can be prepared simply and quickly by one-pot method at room temperature.

[0024] 2) The fluorescent silver-platinum nanocluster material provided by the present application not only has an atomic-level precise structure, but also has high stability and high dispersity. The absolute quantum yield of the fluorescent silver-platinum nanocluster material is 9.9% at room temperature. The fluorescent silver-platinum nanocluster material exhibits excellent fluorescence selectivity and sensitivity to mercury ions, and the detection limit is as low as 92.6 nM, which has good application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 The structure diagram of the fluorescent silver-platinum nanocluster material prepared by the present application;

[0026] Figure 2 The electrospray high-resolution mass spectrum of the fluorescent silver-platinum nanocluster material prepared in Examples 1-3;

[0027] Figure 3 The differential pulse voltammogram of the fluorescent silver-platinum nanocluster material prepared in Examples 1-3;

[0028] Figure 4 The ultraviolet absorption spectrum of the crystal solution of the fluorescent silver-platinum nanocluster material prepared in Examples 1-3 after being placed for different time;

[0029] Figure 5 The excitation spectrum and emission spectrum of the fluorescent silver-platinum nanocluster material prepared in Examples 1-3;

[0030] Figure 6The absolute quantum yield chart of the fluorescent silver-platinum nanocluster material prepared in Example 1-3;

[0031] Figure 7 The chart of the change of the relative fluorescent intensity of the fluorescent silver-platinum nanocluster material solution prepared in Example 1-3 added with different ions of the same concentration;

[0032] Figure 8 The fluorescent response chart of the fluorescent silver-platinum nanocluster material solution prepared in Example 1-3 added with mercury ions of different concentrations;

[0033] Figure 9 The linear relationship chart of the fluorescent intensity of the fluorescent silver-platinum nanocluster material solution prepared in Example 1-3 and the concentration of mercury ions. DETAILED DESCRIPTION

[0034] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with examples. All other examples obtained by those skilled in the art without creative labor on the basis of the examples in the present application belong to the protection scope of the present application.

[0035] Example 1

[0036] The present embodiment provides a preparation method of a fluorescent silver-platinum nanocluster material, comprising the following steps:

[0037] S1, dissolve silver trifluoromethanesulfonate (15 mg, 0.058 mmol) in a mixed solvent composed of 9 mL of dichloromethane and 1 mL of methanol, and fully dissolve it by stirring; then add platinum nitrate (2 mg, 0.0063 mmol) and 1,3-bis(diphenylphosphino)propane (30 mg, 0.073 mmol), and continue to stir for 60 min to obtain a uniform mixed solution;

[0038] S2, dissolve sodium borohydride (2 mg, 0.053 mmol) in 1 mL of water, and pour it into the above mixed solution, and react at room temperature for 12 h. After the reaction is completed, a suspension is obtained. Add excess n-hexane to the suspension, centrifuge the suspension at 8900 rpm for 50 seconds, collect the precipitate, and wash and centrifuge it with excess n-hexane to obtain a crude product;

[0039] S3, dissolve the crude product with methanol, then at room temperature, diffuse diethyl ether into the solution by gas phase to induce the formation of crystals, and after three days, yellow rod-shaped transparent crystals, i.e. the fluorescent silver-platinum nanocluster material, are obtained. Collect the crystal product and dry it naturally.

[0040] Example 2

[0041] The present embodiment provides a preparation method of a fluorescent silver-platinum nanocluster material, comprising the following steps:

[0042] S1, dissolve silver trifluoromethanesulfonate (15 mg, 0.058 mmol) in a mixed solvent consisting of 9 mL of dichloromethane and 1 mL of methanol, fully dissolve it by stirring; then add chloroplatinic acid (2.5 mg, 0.0061 mmol) and 1,3-bis(diphenylphosphino)propane (35 mg, 0.085 mmol), continue stirring for 60 min to obtain a uniform mixed solution;

[0043] S2, dissolve sodium borohydride (1 mg, 0.026 mmol) in 1 mL of water, and pour it into the above mixed solution, react at room temperature for 12 h, and obtain a suspension after the reaction is completed; add excess n-hexane to the suspension, centrifuge the suspension at 8900 rpm for 45 s, collect the precipitate and wash and centrifuge it with excess n-hexane to obtain a crude product;

[0044] S3, dissolve the crude product with methanol, then at room temperature, diffuse diethyl ether into the solution in the gas phase to induce the formation of crystals, and after three days, yellow rod-shaped transparent crystals, i.e., the fluorescent silver-platinum nanocluster material, are obtained; collect the crystal product and air dry it naturally.

[0045] Example 3

[0046] The embodiment provides a preparation method of a fluorescent silver-platinum nanocluster material, comprising the following steps:

[0047] S1, dissolve silver trifluoromethanesulfonate (15 mg, 0.058 mmol) in a mixed solvent consisting of 9 mL of dichloromethane and 1 mL of methanol, fully dissolve it by stirring; then add chloroplatinic acid (4 mg, 0.0098 mmol) and 1,3-bis(diphenylphosphino)propane (40 mg, 0.097 mmol), continue stirring for 60 min to obtain a uniform mixed solution;

[0048] S2, dissolve sodium borohydride (5 mg, 0.132 mmol) in 1 mL of water, and pour it into the above mixed solution, react at room temperature for 12 h, and obtain a suspension after the reaction is completed; add excess n-hexane to the suspension, centrifuge the suspension at 8900 rpm for 60 s, collect the precipitate and wash and centrifuge it with excess n-hexane to obtain a crude product;

[0049] S3, dissolve the crude product with methanol, then at room temperature, diffuse diethyl ether into the solution in the gas phase to induce the formation of crystals, and after three days, yellow rod-shaped transparent crystals, i.e., the fluorescent silver-platinum nanocluster material, are obtained; collect the crystal product and air dry it naturally.

[0050] The fluorescent silver-platinum nanocluster material prepared in Examples 1-3 is taken for further characterization, and the process is as follows:

[0051] (1) Crystal structure determination

[0052] Under nitrogen protection and low temperature conditions of 193K, the crystal products of Examples 1-3 were selected and tested using a single crystal X-ray diffractometer (model Bruker D8 Venture) under a microscope. The Ga-Kα rays were diffracted, and the diffraction data were collected using the ω scanning method. The single crystal structure was solved by the direct method using the SHELXL-97 software program, the refinement method used the least squares method F2, and the empirical absorption correction used the SADABS program. First, the positions of all non-hydrogen atoms were determined and anisotropic corrections were made. All Ag, Pt, P, Cl and C atoms were directly discovered, and the hydrogen atom positions in the molecule were refined using isotropic calculations. Detailed crystal measurement data are shown in Table 1. Figure 1 As shown in the results, the precise structure of the fluorescent silver platinum nanocluster after analysis is [Ag 14 Pt(Dppp)6Cl4], whose structure consists of 14 Ag atoms, one Pt atom, 6 dppp organic ligands and 4 halogen Cl ligands.

[0053] Table 1 Main crystallographic parameters

[0054]

[0055]

[0056] R1=∑||Fo|-|Fc|| / ∑|Fo|.wR2=[∑w(F o 2 -F c 2 ) 2 / ∑w(F o 2 ) 2 ] 1 / 2

[0057] Figure 2 This is an electrospray ionization high-resolution mass spectrometry (instrument model: Waters Xevo G3 QTOF) of the fluorescent silver platinum nanocluster material prepared in Example 1-3, which confirms that the material has good dispersibility in the solution.

[0058] Figure 3 This is the differential pulse voltammogram of the fluorescent silver-platinum nanocluster material prepared in Example 1 (the instrument model is Shanghai Chenhua CHI600E), which confirms that the electrochemical energy gap of the material is as high as 1.53V.

[0059] Figure 4The UV absorption spectra of the fluorescent silver-platinum nanocluster material crystal solution prepared in Example 1 after being placed for different periods of time (the instrument model is Yuanxi UV8000) confirm that the material has high stability and its UV-visible spectrum does not change significantly after being stored at room temperature and pressure for at least 30 days.

[0060] Figure 5 The excitation spectrum and emission spectrum of the fluorescent silver platinum nanocluster material prepared in Example 1 (instrument model is PerkinElmer FL8500) confirm that the material has strong emission characteristics, with a maximum excitation wavelength at 392nm and an optimal emission wavelength position in the yellow light region at 592nm.

[0061] Figure 6 This is a graph of the absolute quantum yield of the fluorescent silver-platinum nanocluster material prepared in Example 1 (the instrument model is Edinburgh FLS1000), which confirms that the absolute quantum yield of the fluorescent silver-platinum nanocluster material at room temperature reaches 9.9%.

[0062] (2) Application of fluorescent silver platinum nanocluster materials as mercury ion detection probes

[0063] The fluorescent silver-platinum nanocluster material (3 mg) prepared in Example 1-3 was dissolved in 50 mL of N,N-dimethylformamide to prepare a solution with a concentration of 14 μM. Subsequently, under 430 nm long wavelength excitation, the relative fluorescence intensity change (I0 / I) of the emission peak at 592 nm was measured, where I0 and I represent the fluorescence intensity of the solution before and after adding different ions with a volume of 100 μL and a concentration of 100 μM to 1 mL of 14 μM silver-platinum nanocluster solution. The results show that the fluorescent silver-platinum nanocluster material solution of the present invention has a strong effect on Hg 2+ Has good selectivity ( Figure 7 ).

[0064] Under the excitation of 430nm wavelength, after adding 100uL of mercury ion standard solution with concentrations of 2μM, 3μM, 5μM, 9μM and 10μM to 1mL of 14μM fluorescent silver platinum nanocluster material solution, the fluorescence intensity change at 592nm was monitored ( Figure 8 ), fitting the linear relationship between the emission peak signal intensity and the concentration of mercury ions ( Figure 9 ), the results show that the fluorescent silver platinum nanocluster material solution of the present invention has a great influence on Hg 2+ It has good sensitivity and can achieve sensitive and specific detection of mercury ions, with a detection limit as low as 92.6nM.

[0065] Those skilled in the art should understand that the above description is only several specific embodiments of the present application, not all embodiments. It should be noted that many modifications and improvements can also be made by those of ordinary skill in the art, and all modifications and improvements that do not exceed the scope of the claims should be considered as the protection scope of the present application.

Claims

1. A fluorescent silver-platinum nanocluster material, characterized in that: The cationic chemical formula of the fluorescent silver platinum nanocluster material is C 162 H 156 Ag 14 Cl4P 12 Pt, abbreviated as Ag 14 Pt(Dppp)6Cl4, belongs to the monoclinic system; the space group is P21 / c, α=90°, β=112.279(4)°, γ=90°, The molecular weight is 4321.57Da; Dppp is 1,3-bis(diphenylphosphino)propane, and the simplified structural formula is as follows:

2. A method for preparing the fluorescent silver-platinum nanocluster material according to claim 1, comprising the following steps: S1. Add silver trifluoromethanesulfonate to a mixed solvent of dichloromethane and methanol, stir to fully dissolve, then add platinum salt and 1,3-bis(diphenylphosphine)propane, and continue stirring to obtain a uniform mixed solution; S2. A sodium borohydride aqueous solution is added to the mixed solution, and the mixture is reacted at room temperature for 12-20 hours to obtain a suspension. Excess n-hexane is added to the suspension, and the precipitate is collected by centrifugation and washed again with excess n-hexane and centrifuged to obtain a crude product. S3. Dissolve the crude product in methanol, then induce the formation of crystals by vapor-diffusion of ether into the solution at room temperature, collect the crystalline products, and dry them naturally to obtain fluorescent silver-platinum nanocluster materials.

3. The method for preparing the fluorescent silver-platinum nanocluster material according to claim 2, wherein: The molar mass ratio of the silver trifluoromethanesulfonate, platinum salt, 1,3-bis(diphenylphosphino)propane and sodium borohydride is 1:(0.1-0.5):(1-2):(0.4-2.5).

4. The method for preparing the fluorescent silver-platinum nanocluster material according to claim 2 or 3, wherein: The platinum salt in step S1 is chloroplatinic acid or platinum nitrate.

5. The method for preparing the fluorescent silver-platinum nanocluster material according to claim 2, wherein: In step S1, dichloromethane and methanol are mixed in a volume ratio of 9:1 to form a mixed solvent, and the amount of silver trifluoromethanesulfonate added to the mixed solvent is 1-2 mg / ml.

6. The method for preparing the fluorescent silver-platinum nanocluster material according to claim 2, wherein: The concentration of the sodium borohydride aqueous solution in step S2 is 0.8-5.4 mg / ml.

7. The method for preparing the fluorescent silver-platinum nanocluster material according to claim 2, wherein: In step S2, the precipitate is collected by centrifugation at a speed of 8500-10000 rpm for 40-60 seconds.

8. Use of the fluorescent silver-platinum nanocluster material according to claim 1 in detecting mercury ions.

9. The use of the fluorescent silver platinum nanocluster material in detecting mercury ions according to claim 8 is characterized in that: Under excitation at a wavelength of 430 nm, a standard mercury ion solution was added to a solution containing fluorescent silver-platinum nanocluster material at a volume ratio of 1:

10. The concentration of the standard mercury ion solution was 1-10 μM, and the concentration of the solution containing fluorescent silver-platinum nanocluster material was 10-18 μM. The emission peak intensity of the solution at 592 nm was significantly reduced.

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