Fluorescent silver-platinum nano-cluster material as well as preparation method and application thereof

Abstract

The invention belongs to the crossing field of nano materials and coordination chemistry, and particularly discloses a fluorescent silver-platinum nano-cluster material, a preparation method and application of the fluorescent silver-platinum nano-cluster material as a mercury ion detection probe in mercury ion detection. The chemical formula of the fluorescent silver-platinum nano-cluster material is C162H156Ag14Cl4P12Pt, the fluorescent silver-platinum nano-cluster material is abbreviated as Ag14Pt (Dppp) 6Cl4, and the fluorescent silver-platinum nano-cluster material belongs to a monoclinic system; the space group is P21 / c, the alpha is 90 degrees, the beta is 112.279 (4) degrees, the gamma is 90 degrees, and the molecular weight of the # imgabs2 is 4321.57 Da. The preparation method provided by the invention does not need a complex technological process, synthesis is carried out at normal temperature and normal pressure, the operation steps are simple, and raw materials are easy to obtain. The fluorescent silver-platinum nano-cluster material is high in stability, the electrochemical energy gap is up to 1.53 V, the fluorescent silver-platinum nano-cluster material can be stored for at least 30 days under the conditions of normal temperature and normal pressure, and the fluorescent silver-platinum nano-cluster material shows excellent fluorescence selectivity and sensitivity to mercury ions and has a good application prospect.

Description

Technical Field

[0001] The invention belongs to the cross field of nano materials and coordination chemistry, and in particular relates to a fluorescent silver-platinum nanocluster material and a preparation method thereof and application in mercury ion detection. Background Art

[0002] Mercury ions have been listed as a key pollutant by various national institutions and international organizations due to their extremely high toxicity and difficulty in biodegradation. Mercury ions can accumulate in organisms through the food chain and eventually enter the human body, leading to a decline in human immunity and damaging the immune system function, thereby increasing the incidence of a variety of epidemics and chronic diseases. Designing new materials and developing easy-to-use analytical techniques for real-time and rapid detection of mercury ions in real samples are prerequisites for protecting the natural environment and preventing human diseases. To date, various analytical techniques such as inductively coupled plasma mass spectrometry, high performance liquid chromatography, gas chromatography, atomic absorption spectrometry, atomic fluorescence spectrometry, X-ray fluorescence spectrometry, electrochemical analysis, etc. have been widely used in the detection of heavy metal ions. However, these analytical techniques usually rely on bulky and expensive 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 are simple to operate during the detection process, do not require complex sample pretreatment, are less destructive to samples, and are low in cost, so they have attracted widespread attention from researchers.

[0003] However, fluorescent nanoclusters are easily aggregated 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 research reports on fluorescent nanoclusters with precise single crystal structure and high stability that can achieve specific detection of mercury ions. Summary of the invention

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

[0005] One of the purposes of the present invention is to provide a fluorescent silver-platinum nanocluster material, the chemical formula of which 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(diphenylphosphine)propane, and the structural formula is as follows:

[0006]

[0007] Further improvements as fluorescent silver platinum nanocluster materials:

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

[0009] The second object of the present invention is to provide a method for preparing the fluorescent silver-platinum nanocluster material described in any one of the above, comprising the following steps:

[0010] S1, adding silver trifluoromethanesulfonate to a mixed solvent of dichloromethane and methanol, stirring to fully dissolve, then adding platinum salt and 1,3-bis(diphenylphosphine)propane, and continuing to stir to obtain a uniform mixed solution;

[0011] S2, adding sodium borohydride aqueous solution to the mixed solution, and reacting at room temperature for 12-20 hours to obtain a suspension, adding excess n-hexane to the suspension, collecting the precipitate by centrifugation, and washing and centrifuging again with excess n-hexane to obtain a crude product;

[0012] S3. Dissolve the crude product with methanol, then induce the formation of crystals by vapor-diffusion of ether into the solution at room temperature, collect the crystal products, and dry them naturally to obtain fluorescent silver-platinum nanocluster materials.

[0013] As a further improvement of the preparation method of the above fluorescent silver platinum nanocluster material:

[0014] Preferably, the molar mass ratio of the silver trifluoromethanesulfonate, the platinum salt, 1,3-bis(diphenylphosphine)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 amount of silver trifluoromethanesulfonate added to the mixed solvent is 1-2 mg / ml.

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

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

[0019] A second object of the present invention is to provide an application of the fluorescent silver-platinum nanocluster material described in any one of the above items in detecting mercury ions.

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

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

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1) The preparation method of the present invention provides a reference for the synthesis technology of fluorescent nanoclusters. The preparation method provided by the present invention has a simple operation process, mild reaction conditions, low cost, no need for calcination, no need for complicated process flow, and is synthesized at room temperature and pressure. The operation steps are simple and the raw materials are easily available. Fluorescent silver platinum nanoclusters can be prepared simply and quickly by a one-pot method at room temperature.

[0024] 2) The present invention provides a fluorescent silver-platinum nanocluster material which not only has an atomic-level precise structure, but also has high stability and high dispersibility. The absolute quantum yield at room temperature reaches 9.9%. It exhibits excellent fluorescence selectivity and sensitivity to mercury ions, with a detection limit as low as 92.6 nM, and has good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of the structure of the fluorescent silver-platinum nanocluster material prepared by the present invention;

[0026] Figure 2 This is the electrospray ionization high-resolution mass spectrum of the fluorescent silver-platinum nanocluster material prepared in Example 1-3;

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

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

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

[0030] Figure 6This is a graph of the absolute quantum yield of the fluorescent silver-platinum nanocluster material prepared in Example 1-3;

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

[0032] Figure 8 The fluorescence response diagram of adding different concentrations of mercury ions to the fluorescent silver platinum nanocluster material solution prepared in Example 1-3;

[0033] Fig. 9 This is a linear relationship diagram between the fluorescence intensity and mercury ion concentration of the fluorescent silver-platinum nanocluster material solution prepared in Example 1-3. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present invention.

[0035] Example 1

[0036] This embodiment provides a method for preparing a fluorescent silver-platinum nanocluster material, comprising the following steps:

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

[0038] S2, dissolving sodium borohydride (2 mg, 0.053 mmol) in 1 mL of water, and pouring into the above mixed solution, reacting at room temperature for 12 h, and obtaining a suspension after the reaction, adding excess n-hexane to the suspension, and centrifuging the suspension at 8900 rpm for 50 seconds, collecting the precipitate, washing it with excess n-hexane, and centrifuging it to obtain a crude product;

[0039] S3. Dissolve the crude product with methanol, and then diffuse ether into the solution at room temperature to induce crystal formation. Three days later, yellow rod-shaped transparent crystals, i.e., fluorescent silver-platinum nanocluster materials, are obtained. Collect the crystalline products and dry them naturally.

[0040] Example 2

[0041] This embodiment provides a method for preparing 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, and stir to fully dissolve it; then add chloroplatinic acid (2.5 mg, 0.0061 mmol) and 1,3-bis(diphenylphosphine)propane (35 mg, 0.085 mmol), and continue stirring for 60 min to obtain a uniform mixed solution;

[0043] S2, dissolving sodium borohydride (1 mg, 0.026 mmol) in 1 mL of water, and pouring the mixture into the above mixed solution, reacting at room temperature for 12 h, and obtaining a suspension after the reaction, adding excess n-hexane to the suspension, and centrifuging the suspension at 8900 rpm for 45 seconds, collecting the precipitate, washing it with excess n-hexane, and centrifuging it to obtain a crude product;

[0044] S3. Dissolve the crude product with methanol, and then diffuse ether into the solution at room temperature to induce crystal formation. Three days later, yellow rod-shaped transparent crystals, i.e., fluorescent silver-platinum nanocluster materials, are obtained. Collect the crystalline products and dry them naturally.

[0045] Example 3

[0046] This embodiment provides a method for preparing 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, and stir to fully dissolve it; then add chloroplatinic acid (4 mg, 0.0098 mmol) and 1,3-bis(diphenylphosphine)propane (40 mg, 0.097 mmol), and continue stirring for 60 min to obtain a uniform mixed solution;

[0048] S2, dissolving sodium borohydride (5 mg, 0.132 mmol) in 1 mL of water, and pouring into the above mixed solution, reacting at room temperature for 12 h, and obtaining a suspension after the reaction, adding excess n-hexane to the suspension, and centrifuging the suspension at 8900 rpm for 60 seconds, collecting the precipitate, washing it with excess n-hexane, and centrifuging it to obtain a crude product;

[0049] S3. Dissolve the crude product with methanol, and then diffuse ether into the solution at room temperature to induce crystal formation. Three days later, yellow rod-shaped transparent crystals, i.e., fluorescent silver-platinum nanocluster materials, are obtained. Collect the crystalline products and dry them naturally.

[0050] The fluorescent silver-platinum nanocluster materials of the present invention prepared in Examples 1-3 were further characterized, and the process was as follows:

[0051] (1) Crystal structure determination

[0052] Under nitrogen protection and low temperature conditions of 193K, the crystal products in Examples 1-3 were selected under a microscope and tested using a single crystal X-ray diffractometer (model: Bruker D8 Venture). The Ga-Kα rays were used for diffraction, and the diffraction data were collected by ω scanning. The single crystal structure was solved by the direct method using the SHELXL-97 software program, and 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 The results show that the precise structure of the fluorescent silver-platinum nanoclusters 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 spectrometer (the instrument model is 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 The differential pulse voltammogram of the fluorescent silver-platinum nanocluster material prepared in Example 1 (the instrument model is Shanghai Chenhua CHI600E) 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), confirming 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 (the instrument model is PerkinElmer FL8500) confirm that the material has strong emission characteristics, the maximum excitation wavelength is at 392nm, and the optimal emission wavelength is 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 significant effect on Hg 2+ Has good selectivity ( Figure 7 ).

[0064] Under the excitation of 430nm wavelength, after adding 100uL of mercury ion standard solutions 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 ( Fig. 9 ), the results show that the fluorescent silver platinum nanocluster material solution of the present invention has a significant effect 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 are only some specific embodiments of the present invention, rather than all embodiments. It should be noted that for those of ordinary skill in the art, many modifications and improvements can be made, and all modifications or improvements that do not exceed the scope of protection of the present invention should be regarded as the scope of protection of the present invention.

Claims

1. A fluorescent silver-platinum nanocluster material, characterized in that: The 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(diphenylphosphine)propane, and the structural formula is as follows:

2. The fluorescent silver-platinum nanocluster material according to claim 1, characterized in that: The structure of the fluorescent silver-platinum nanocluster material consists of 14 Ag atoms, one Pt atom, 6 dppp organic ligands and 4 halogen Cl ligands.

3. A method for preparing the fluorescent silver-platinum nanocluster material according to claim 1 or 2, characterized in that it comprises the following steps: S1, adding silver trifluoromethanesulfonate to a mixed solvent of dichloromethane and methanol, stirring to fully dissolve, then adding platinum salt and 1,3-bis(diphenylphosphine)propane, and continuing to stir to obtain a uniform mixed solution; S2, adding sodium borohydride aqueous solution to the mixed solution, and reacting at room temperature for 12-20 hours to obtain a suspension, adding excess n-hexane to the suspension, collecting the precipitate by centrifugation, and washing and centrifuging again with excess n-hexane to obtain a crude product; S3. Dissolve the crude product with methanol, then induce the formation of crystals by vapor-diffusion of ether into the solution at room temperature, collect the crystal products, and dry them naturally to obtain fluorescent silver-platinum nanocluster materials.

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

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

6. The method for preparing the fluorescent silver-platinum nanocluster material according to claim 3, characterized in that: 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.

7. The method for preparing the fluorescent silver-platinum nanocluster material according to claim 3, characterized in that: The concentration of the sodium borohydride aqueous solution in step S2 is 0.8-5.4 mg / ml.

8. The method for preparing the fluorescent silver-platinum nanocluster material according to claim 3, characterized in that: In step S2, the precipitate is collected by centrifugation at a speed of 8500-10000 rpm for 40-60 seconds.

9. Use of the fluorescent silver-platinum nanocluster material according to claim 1 or 2 in detecting mercury ions.

10. The use of the fluorescent silver platinum nanocluster material in detecting mercury ions according to claim 9 is characterized in that: Under excitation at a wavelength of 430 nm, the standard mercury ion solution was added to a solution containing fluorescent silver-platinum nanocluster materials 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 materials was 10-18 μM. The emission peak intensity of the solution at 592 nm was greatly reduced.

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