Silver metal nano material, preparation method and application thereof

Abstract

The invention discloses a novel metal nano material, and particularly provides a silver metal nano material, a preparation method and application thereof. The material shows excellent ratio fluorescence temperature measurement performance, and the ratio of the fluorescence intensity at 626 nm to the fluorescence intensity at 568 nm has a good linear relationship with the temperature. The silver metal nanomaterial can be used as a high-precision ratio fluorescence thermometer, and has better application in the fields of biomedical treatment, environmental monitoring, nanoelectronics and the like.

Description

Technical Field

[0001] The invention relates to a silver metal nano material, a preparation method and application thereof, and belongs to the technical field of metal nano materials. Background Art

[0002] Fluorescence thermometers have the advantages of non-invasive, remote temperature measurement, high sensitivity and high spatial resolution, and can work normally in special environments such as biological matrices, fast movement or ultra-small spaces. Therefore, they have broad application prospects in many hot fields such as biomedicine (such as protein folding, calcium signal transduction), environmental science and nanoelectronics. Many optical temperature sensors are realized by monitoring changes in luminescence intensity. However, intensity-based temperature sensors are often interfered by factors such as changes in probe concentration, excitation strength and detection efficiency, resulting in unstable measurement results. Dual-emission temperature sensors effectively overcome many challenges faced by absolute intensity luminescence sensors, including optical occlusion, concentration changes and lack of specificity, by providing an internal reference (ratio) signal. Therefore, among all types of fluorescence thermometers, ratio fluorescence thermometers are the most practical.

[0003] Fluorescent silver nanoclusters in metal nanomaterials have attracted much attention due to their rich topological structures and diverse fluorescence properties. The non-radiative decay of silver nanoclusters is easily affected by temperature, and their fluorescence emission intensity usually shows good temperature dependence. Therefore, silver nanoclusters show broad prospects in the application of fluorescence temperature detection. In addition, they also have excellent photostability, biocompatibility and low toxicity, and have good application prospects in the biomedical field. At present, some silver nanoclusters with temperature-dependent fluorescence intensity signal emission have been synthesized and reported, but silver nanoclusters that exhibit good ratiometric fluorescence temperature measurement properties are still relatively limited. Summary of the invention

[0004] The present invention aims to provide a novel metal nanomaterial, which can be used as a ratiometric fluorescence temperature measurement material and applied in technical fields such as biomedicine (such as protein folding, calcium signal transduction), environmental science, and nanoelectronics.

[0005] The first object of the present invention is to provide a new type of silver metal nanomaterial, whose molecular formula is Ag 26 (H2decz)2(Hdecz)8(PhCOO)6(P(PhOMe)3)6(NO3)2;

[0006] The "H2decz" is The "Hdecz" is The PhCOO is benzoate The P(PhOMe)3 is tri(4-methoxyphenyl)phosphine NO3 is nitrate.

[0007] According to the preferred embodiment of the present invention, the above silver metal nanomaterial can be prepared by the following method:

[0008] (1) Alkyne silver precursor: Under alkaline conditions, silver (I) salt and 3,6-di-tert-butyl-1,8-diethyl-9H-carbazole undergo polymerization reaction in a solvent to generate an acetylenic silver precursor;

[0009] (2) dissolving the silver acetylene precursor, silver (I) benzoate, tri(4-methoxyphenyl)phosphine and nitrate in a solvent to prepare the silver metal nanomaterial through a self-assembly reaction;

[0010] Wherein, the structural formula of the 3,6-di-tert-butyl-1,8-diethyl-9H-carbazole is

[0011] Preferably according to the present invention, in step (1), the silver (I) salt may be one or a combination of more than one of Ag2O, AgNO3, AgF, AgCl, AgBr, AgI, CF3SO3Ag, AgClO4, AgBF4, AgPF6 or AgSbF6.

[0012] Preferably according to the present invention, in step (1), the solvent may be one or a combination of more than one of water, chloroform, dichloromethane, acetonitrile, ethanol or methanol.

[0013] Preferably according to the present invention, in step (1), the base can be one or a combination of more than one of ammonia water, triethylamine, sodium hydroxide, potassium hydroxide, sodium hydride or calcium hydride, sodium methoxide, sodium ethoxide, n-butyl lithium, tert-butyl lithium, tetramethylethylenediamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide and tetrabutylammonium hydroxide.

[0014] Preferably according to the present invention, in step (1), the molar ratio of the silver (I) salt to 3,6-di-tert-butyl-1,8-diethyl-9H-carbazole is 2-2.5:1.

[0015] Preferably according to the present invention, in step (2), the nitrate may be one or a combination of more than one of potassium nitrate, sodium nitrate, ammonium nitrate, tetramethylammonium nitrate, tetraethylammonium nitrate, tetrapropylammonium nitrate and tetrabutylammonium nitrate.

[0016] Preferably according to the present invention, in step (2), the reaction ratio of the acetylenic silver precursor, silver (I) benzoate, tri(4-methoxyphenyl)phosphine and nitrate is 9-11:5-7:5-7:1-3, and the optimal reaction molar ratio is 10:6:6:2.

[0017] Preferably according to the present invention, in step (2), the solvent may be one or a combination of more than one of methanol, dichloromethane, chloroform, acetonitrile, 1,2-dichloroethane, dimethyl sulfoxide, N,N-dimethylformamide, and N,N-dimethylacetamide.

[0018] Preferably, according to the present invention, in step (2), the reaction conditions can be either room temperature stirring or low temperature solvent heating.

[0019] The second object of the invention is to provide a method for preparing the above-mentioned silver metal nanomaterial, which can be prepared by the method for preparing the above-mentioned silver metal nanomaterial in this article.

[0020] Invention Objective 3: To provide a crystal form of the above silver metal nanomaterial, wherein the unit cell parameters of the crystal form are: α(deg)=62.986(2); β(deg)=75.697(2); γ(deg)=88.734(3).

[0021] A fourth object of the invention is to provide an application of the above-mentioned silver metal nanomaterial in a ratio fluorescence thermometer.

[0022] The thermoluminescent color-changing properties of the silver metal nanomaterial were studied. At room temperature, when excited at 365nm, its maximum emission peak was located at 600nm, and there was also a small shoulder peak at 500nm. When the temperature gradually decreased to -190°C, the maximum emission peak centered at 600nm gradually red-shifted to 626nm, and the luminescence intensity increased by 16 times. The small shoulder peak at 500nm gradually red-shifted to 510nm, and the emission intensity increased by nearly 31 times. In addition, two new emission peaks appeared at 552nm and 568nm.

[0023] The silver metal nanomaterial has application potential in the field of fluorescence temperature measurement technology. The emission intensity at 552nm, 568nm, 600nm and 626nm shows a good linear response relationship with temperature, while the emission intensity at 510nm shows a good exponential response relationship with temperature.

[0024] The silver metal nanomaterial has application potential in the field of ratio fluorescence temperature measurement technology. The ratio of the fluorescence intensity at 626nm to the fluorescence intensity at 568nm shows a good linear dependence on temperature.

[0025] It can be seen that the above-mentioned silver metal nanomaterials can be used as the core material of a high-precision ratio fluorescence thermometer.

[0026] Without violating the common sense in the art, the above-mentioned preferred conditions can be arbitrarily combined to obtain the preferred embodiments of the present invention.

[0027] Unless otherwise specified, the reagents and raw materials used in the present invention are commercially available.

[0028] The technical features and beneficial effects of the present invention are as follows:

[0029] 1. The synthesis process of the silver metal nanomaterial of the present invention is simple, the conditions are mild, and it is suitable for large-scale production.

[0030] 2. In the wide temperature range of 30℃ to -150℃, silver metal nanomaterials exhibit excellent temperature-dependent fluorescence properties in the solid state. The fluorescence intensity at 552nm, 568nm, 600nm and 626nm shows a linear relationship with temperature change, while the fluorescence intensity at 510nm shows an exponential relationship with temperature change. This unique response mechanism enables silver metal nanomaterials to not only have multi-band selectivity in temperature measurement, but also realize multi-parameter analysis through the response modes of different fluorescence wavelengths, broadening its application prospects for temperature detection in complex environments.

[0031] 3. In the temperature range of 30℃ to -150℃, the multiple emission characteristics of silver metal nanomaterials give it the ability to self-correct fluorescence temperature measurement, effectively avoiding interference caused by external factors such as concentration changes, excitation conditions and detection efficiency. In addition, there is a good linear relationship between the ratio of fluorescence intensity at 626nm and 568nm and temperature, which further improves its stability and accuracy in fluorescence temperature sensing. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a single crystal structure diagram of silver metal nanomaterials. For simplicity, hydrogen atoms and the tert-butyl group on 3,6-di-tert-butyl-1,8-diethyl-9H-carbazole are omitted.

[0033] Figure 2 is the UV-visible absorption curve of silver metal nanomaterials in dichloromethane solution

[0034] Figure 3 is the excitation of silver metal nanomaterials in the solid state (λ em = 600nm, dotted line) and emission (λ ex =365nm, solid line)

[0035] Figure 4 is the maximum emission peak of silver metal nanomaterials in the solid state (λ max =600nm) life decay curve

[0036] Figure 5 This is the temperature-dependent fluorescence curve of silver metal nanomaterials in the solid state, with an excitation wavelength of 365nm

[0037] Figure 6The emission intensity of solid silver metal nanomaterials at different emission wavelengths varies with temperature under 365nm ultraviolet light excitation; (A) the response curve of emission intensity at 510nm and temperature; (B) the response curve of emission intensity at 552nm and temperature; (C) the response curve of emission intensity at 568nm and temperature; (D) the response curve of emission intensity at 600nm and temperature; (E) the response curve of emission intensity at 626nm and temperature; (F) the response curve of the ratio of emission intensity at 626nm to emission intensity at 568nm and temperature of solid silver metal nanomaterials under 365nm ultraviolet light excitation. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical scheme and technical effect of the present invention clearer, the present invention is further described in detail below with reference to the accompanying drawings and embodiments, but is not limited thereto; however, the present invention is not limited to the embodiments, and the experimental methods for which specific conditions are not specified in the following embodiments shall be selected according to conventional methods and conditions, or according to the product instructions.

[0039] The 3,6-di-tert-butyl-1,8-diethyl-9H-carbazole involved in the examples was prepared according to Dalton Trans. 2017, 46, 4696-4710, and other reagents and solvents were conventional products. The methods used were all prior art unless otherwise specified.

[0040] Example 1: Synthesis method of silver metal nanomaterials in the present invention

[0041] (1) Add 0.1 mmol Ag2O to 10 ml of 25% ammonia water, stir with a magnetic bar for five minutes to obtain a clear silver ammonia solution. Subsequently, dissolve 0.1 mmol 3,6-di-tert-butyl-1,8-diethyl-9H-carbazole in 3 ml 1,4-dioxane, and add the silver ammonia solution dropwise under vigorous stirring. Stirring continues for 6 hours. Filter, wash with deionized water 3 times, and vacuum dry to obtain a red silver acetylene precursor with a yield of 82.7%.

[0042] (2) 0.10mmol of acetylene silver precursor, 0.06mmol of silver (I) benzoate, 0.06mmol of tri(4-methoxyphenyl)phosphine and 0.02mmol of tetraethylammonium nitrate were dissolved in 10ml of dichloromethane and stirred at room temperature for 12 hours to generate a deep red solution. Finally, the reaction mother liquor was concentrated to 3ml and transferred to a test tube of 15x150 cm. 15ml of n-hexane was spread on the mother liquor for interfacial diffusion. The mixture was sealed and kept away from light for one week to obtain red block silver metal nanomaterial crystals with a crystal yield of 75.5%.

[0043] Example 2: Synthesis method of silver metal nanomaterials in the present invention

[0044] (1) Weigh 0.2mmol AgNO3, dissolve it in water, and then add ammonia water with a mass concentration of 25% dropwise. A gray precipitate will be generated initially, and then the precipitate will gradually dissolve. When the solution becomes clear again, stop adding drops to obtain a silver ammonia solution. Next, dissolve 0.1mmol 3,6-di-tert-butyl-1,8-diethyl-9H-carbazole in 3ml 1,4-dioxane, and add the silver ammonia solution dropwise under vigorous stirring. The reaction quickly forms a red precipitate, and stirring is continued for 6 hours. Then, filter and wash with water 3 times, and vacuum dry the water to obtain a red silver acetylene precursor with a yield of 83.5%.

[0045] (2) 0.10mmol of acetylene silver precursor, 0.06mmol of silver (I) benzoate, 0.06mmol of tri(4-methoxyphenyl)phosphine and 0.02mmol of ammonium nitrate were dissolved in 10ml of dichloromethane and stirred at room temperature for 12 hours to obtain a deep red solution. Finally, the reaction mother liquor was concentrated to 3ml and transferred to a 15x 150 test tube. 15ml of n-hexane was spread on the mother liquor for interfacial diffusion. The mixture was sealed and kept away from light for one week to obtain red bulk silver metal nanomaterial crystals with a crystal yield of 75.8%.

[0046] Example 3: Synthesis method of silver metal nanomaterials in the present invention

[0047] (1) Weigh 0.2 mmol of AgClO4 and add it to a methanol solution containing 0.1 mmol of 3,6-di-tert-butyl-1,8-diethyl-9H-carbazole. Under vigorous stirring, add 10 mmol of triethylamine dropwise. The reaction quickly generates a large amount of red precipitate. Continue stirring for 6 hours until the AgClO4 crystals completely disappear. Then filter and wash with methanol 3 times, and vacuum dry the methanol to obtain a red silver acetylene precursor with a yield of 65.0%.

[0048] (2) 0.10 mmol of acetylene silver precursor, 0.06 mmol of silver (I) benzoate, 0.06 mmol of tri(4-methoxyphenyl)phosphine and 0.02 mmol of potassium nitrate were dissolved in 8 ml of a mixed solvent of chloroform:methanol=3:1, and stirred at room temperature for 12 hours to obtain a deep red solution. The reaction mother liquor was placed in a dark place to evaporate slowly, and red flaky silver metal nanomaterial crystals were obtained after one week, with a crystal yield of 59.5%.

[0049] Example 4: Synthesis method of silver metal nanomaterials in the present invention

[0050] (1) Weigh 0.1mmol 3,6-di-tert-butyl-1,8-diethyl-9H-carbazole and 0.2mmol potassium hydroxide, add methanol solvent, and continuously shake with ultrasound until the sodium hydroxide is completely dissolved. Subsequently, add 0.2mmol AgBF4, and a large amount of red precipitate is quickly generated. Continue stirring for 6 hours and then stop the reaction. Filter, wash with methanol three times, and vacuum dry to obtain silver acetylene precursor with a yield of 80.3%.

[0051] (2) 0.10mmol of acetylene silver precursor, 0.06mmol of silver (I) benzoate, 0.06mmol of tri(4-methoxyphenyl)phosphine and 0.02mmol of tetramethylammonium nitrate were dissolved in 3ml of N,N-dimethylacetamide and stirred at room temperature for 12 hours to obtain a deep red solution. Finally, the reaction mother liquor was transferred to a 15x 150 test tube, 15ml of ether was added for interfacial diffusion, and the tube was sealed and kept away from light for 7 days to obtain red block silver metal nanomaterial crystals with a crystal yield of 15.5%.

[0052] Example 5: Synthesis method of silver metal nanomaterials in the present invention

[0053] (1) Weigh 0.2 mmol of AgNO3 and add it to a methanol solution containing 0.1 mmol of 3,6-di-tert-butyl-1,8-diethyl-9H-carbazole. Add 10 mmol of triethylamine dropwise under vigorous stirring. The reaction quickly generates a large amount of red precipitate. Continue stirring for 6 hours until all the white silver nitrate crystals disappear. Then filter, wash with methanol 3 times, and vacuum dry the methanol to obtain a red silver acetylene precursor with a yield of 70.6%.

[0054] (2) 0.10 mmol of acetylene silver precursor, 0.06 mmol of silver (I) benzoate, 0.06 mmol of tri(4-methoxyphenyl)phosphine and 0.02 mmol of potassium nitrate were dissolved in 4 ml of a mixed solution of chloroform:methanol = 3:1, and stirred at room temperature for 12 h to obtain a deep red solution. The mother liquor was transferred to a test tube, and 3 volumes of n-hexane were spread on it for interfacial diffusion. The tube was sealed and allowed to stand for 7 days to obtain red bulk silver metal nanomaterial crystals with a crystal yield of 23.4%.

[0055] Embodiment 6:

[0056] The crystal obtained in Example 2 was used as an example for single crystal structure characterization. The X-ray single crystal diffraction data of the crystal was collected on a Bruker DiffractometerMD2 diffractometer at the BL17B beamline of the National Center for Protein Science (NCPSS) in Shanghai. The data was processed using the BrukerAPEX4 program. The wavelength of the light source is The test temperature is 273K. The crystal is triclinic Space group. The unit cell volume is 9527.3(17). Ag 26 The molecular formula of the cluster is C 408 H 386 Ag 26 N 12 O 36 P6, molecular weight is 9023.71. Other parameters are shown in Table 1:

[0057] Table 1

[0058]

[0059] like Figure 1 As shown, the crystal is an atomically precise silver nanocluster with the molecular formula Ag 26 (H2decz)2(Hdecz)8(PhC OO)6(P(PhOMe)3)6(NO3)2. The core of the nanosilver cluster is composed of 26 silver atoms, and the shell is protected by ten deprotonated 3,6-di-tert-butyl-1,8-diethyl-9H-carbazole, six benzoates, six tris(4-methoxyphenyl)phosphine and two nitrates. 3,6-di-tert-butyl-1,8-diethyl-9H-carbazole has two deprotonation modes: two of them remove a hydrogen atom on the ethynyl group and coordinate with the silver atom as a monodentate ligand, and the coordination mode is μ3-η 1 :η 1 :η 1 The remaining eight remove the hydrogen atoms on the two alkynyl groups and act as bidentate ligands to coordinate with the silver atom. There are four ways of coordination with silver: ①μ3-η 1 :η 1 :η 1 ,μ2-η 1 :η 1 ②μ3-η 1 :η 1 :η 1 ,μ4-η 2 :η 1 :η 1 :η 1 ③μ3-η 1 :η 1 :η 1 ,μ3-η 1 :η 1 :η 1 ④μ3-η 2 :η 1 :η 1 ,μ3-η 2 :η 1 :η 1 Nitrate and benzoate use bidentate coordination mode to bridge silver atoms. Benzoate can be divided into two groups: one group of four benzoate groups coordinates with two silver atoms. The other group of four benzoate groups coordinates with three silver atoms. Nitrate bridges three silver atoms Six tri(4-methoxyphenyl)phosphines are coordinated with one silver atom through their phosphorus atoms and evenly surround the Ag. 26 Around the core. Under the synergistic protection of these four ligands, the silver nanocluster has good stability.

[0060] Example 7: Photophysical testing

[0061] The UV-Vis absorption spectrum of the material was measured on a Perkin-Elmer Lambda 365 UV-Vis spectrophotometer. The UV-Vis absorption test showed that the silver metal nanomaterial mainly exhibited four UV absorption peaks at 300nm, 310nm, 362nm and 396nm in a dichloromethane solution (e.g. Figure 2 shown).

[0062] The excitation and emission spectra and emission lifetime of the material were characterized by Edinburgh Analytical Instruments (FLS920 fluorescence spectrometer). Although silver metal nanomaterials hardly emit light in solution, they emit light when excited (λ ex =200nm-500nm), they can emit orange-red light with a maximum emission wavelength of 600nm (such as Figure 3 As shown), the emission lifetime is 28.1ns (as shown Figure 4 In addition, a small shoulder peak was observed at 500 nm.

[0063] like Figure 5 As shown in the figure, when the temperature drops from 30℃ to -190℃, the emission peak of the silver metal nanomaterial at 600nm gradually red-shifts to 626nm, and the luminescence intensity increases by 16 times. At the same time, the small shoulder peak at 500nm also red-shifts and eventually moves to 510nm. As the temperature drops, the emission intensity at 500nm increases significantly, and the increase exceeds the increase in the emission peak at 600nm. When the temperature drops to -190℃, the luminescence intensity at 500nm increases by nearly 31 times. In addition, as the temperature decreases, two new relatively weak emission peaks appear at 552nm and 568nm.

[0064] The fluorescence intensity of silver metal nanomaterials shows a good dependence on temperature. The emission intensity at 510nm shows a good exponential response relationship with temperature (such as Figure 6The emission intensity at 552nm, 568nm, 600nm and 626nm has a linear response relationship with temperature (as shown in Figure 6 B. Figure 6 C. Figure 6 D and Figure 6 Silver metal nanomaterials also exhibit good ratiometric fluorescence temperature measurement properties. The ratio of the fluorescence intensity at 626nm to the fluorescence intensity at 568nm also has a good linear dependence on temperature (as shown in Figure 6 F).

Claims

1. A silver metal nanomaterial, characterized in that: Its molecular formula is Ag 26 (H2decz)2(Hdecz)8(PhCOO)6(P(PhOMe)3)6(NO3)2; The "H2decz" is The "Hdecz" is The PhCOO is benzoate The P(PhOMe)3 is tri(4-methoxyphenyl)phosphine NO3 is nitrate.

2. The silver metal nanomaterial according to claim 1, characterized in that: The silver metal nanomaterial is prepared by the following method: (1) Under alkaline conditions, silver (I) salt and 3,6-di-tert-butyl-1,8-diethyl-9H-carbazole undergo polymerization reaction in a solvent to generate an acetylene silver precursor; (2) dissolving the silver acetylene precursor, silver benzoate, tri(4-methoxyphenyl)phosphine and nitrate in a solvent to prepare the silver metal nanomaterial through a self-assembly reaction; Wherein, the structural formula of the 3,6-di-tert-butyl-1,8-diethyl-9H-carbazole is 3. The silver metal nanomaterial according to claim 2, characterized in that: In step (1), the silver (I) salt is one or a combination of more than one of Ag2O, AgNO3, AgF, AgCl, AgBr, AgI, CF3SO3Ag, AgClO4, AgBF4, AgPF6 and AgSbF6.

4. The silver metal nanomaterial according to claim 2, characterized in that: In step (1), the solvent is one or a combination of more than one of water, chloroform, dichloromethane, acetonitrile, ethanol or methanol.

5. The silver metal nanomaterial according to claim 2, characterized in that: In step (1), the base is one or a combination of more than one of ammonia water, triethylamine, sodium hydroxide, potassium hydroxide, sodium hydride or calcium hydride, sodium methoxide, sodium ethoxide, n-butyl lithium, tert-butyl lithium, tetramethylethylenediamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, and tetrabutylammonium hydroxide.

6. The silver metal nanomaterial according to claim 2, characterized in that: In step (1), the molar ratio of the silver (I) salt to 3,6-di-tert-butyl-1,8-diethyl-9H-carbazole is 2-2.5:

1.

7. The silver metal nanomaterial according to claim 2, characterized in that: In step (2), the nitrate is one or a combination of more than one of potassium nitrate, sodium nitrate, ammonium nitrate, tetramethylammonium nitrate, tetraethylammonium nitrate, tetrapropylammonium nitrate and tetrabutylammonium nitrate.

8. The silver metal nanomaterial according to claim 2, characterized in that: In step (2), the silver acetylene precursor, The reaction ratio of silver (I) benzoate, tri(4-methoxyphenyl)phosphine and nitrate is 9-11:5-7:5-7:1-3, and the optimal reaction molar ratio is 10:6:6:2; And / or, in step (2), the solvent is one or a combination of more than one of methanol, dichloromethane, chloroform, acetonitrile, 1,2-dichloroethane, dimethyl sulfoxide, N,N-dimethylformamide, and N,N-dimethylacetamide.

9. A crystal form of the silver metal nanomaterial according to any one of claims 1 to 8, characterized in that: The unit cell parameters of the crystal form are: α(deg)=62.986(2); β(deg)=75.697(2); γ(deg)=88.734(3).

10. Use of the silver metal nanomaterial according to any one of claims 1 to 8 in a ratio fluorescence thermometer.

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