Silver metal nanomaterial, preparation method and application thereof

Abstract

The application discloses a novel metal nanomaterial, and particularly provides a silver metal nanomaterial, a preparation method and application thereof. The material exhibits superior ratio fluorescence temperature measurement performance, and a ratio of a fluorescence intensity at 626nm to a fluorescence intensity at 568nm and temperature present a good linear relationship. The silver metal nanomaterial can be used as a high-precision ratio fluorescence thermometer, and has good application in the fields of biological medicine, environmental monitoring and nano-electronics.

Description

Technical Field

[0001] The present 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-invasiveness, remote temperature measurement, high sensitivity and high spatial resolution, and can operate normally in special environments such as biological matrices, fast movement or ultra-small spaces. Therefore, they have broad application prospects in many popular 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 by providing an internal reference (ratio) signal, including optical obstruction, concentration changes and lack of specificity. Therefore, among all types of fluorescence thermometers, ratiometric 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 thermometry properties are still relatively limited. Summary of the Invention

[0004] The present invention aims to provide a novel metal nanomaterial that can be used as a ratiometric fluorescence temperature measurement material and applied in technical fields such as biomedicine (such as protein folding and 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, the molecular formula of which 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 silver metal nanomaterial can be prepared by the following method:

[0008] (1) Silver acetylene 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 silver acetylene 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] According to the present invention, preferably, in step (1), the silver (I) salt can 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] According to the present invention, preferably, 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] According to the preferred embodiment of 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] According to the preferred embodiment of 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] According to the preferred embodiment of 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] According to the preferred embodiment of 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] According to the preferred embodiment of 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] The third object of the invention is to provide a crystal form of the 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 ratiometric fluorescence thermometer.

[0022] The thermoluminescence 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, with a small shoulder peak at 500nm. When the temperature was gradually reduced 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 nanomaterial has great potential in the field of fluorescence temperature measurement. 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. Silver nanomaterials exhibit excellent temperature-dependent fluorescence properties in the solid state over a wide temperature range of 30°C to -150°C. Fluorescence intensities at 552nm, 568nm, 600nm, and 626nm show a linear relationship with temperature, while the fluorescence intensity at 510nm shows an exponential relationship with temperature. This unique response mechanism not only enables multi-band selectivity in temperature measurement, but also enables multi-parameter analysis through response patterns at different fluorescence wavelengths, broadening its application prospects for temperature detection in complex environments.

[0031] 3. Within the temperature range of 30°C to -150°C, the multi-emission properties of silver nanomaterials enable self-calibrating fluorescence temperature measurement, effectively avoiding interference caused by external factors such as concentration changes, excitation conditions, and detection efficiency. Furthermore, the ratio of fluorescence intensities at 626nm to 568nm exhibits a good linear relationship with temperature, further enhancing the stability and accuracy of 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 = 600 nm, dotted line) and emission (λ ex =365nm, solid line) curve

[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 6These are the curves of the emission intensity of solid-state silver metal nanomaterials at different emission wavelengths changing with temperature under 365nm ultraviolet light excitation; among them, (A) the response curve of the emission intensity at 510nm and temperature; (B) the response curve of the emission intensity at 552nm and temperature; (C) the response curve of the emission intensity at 568nm and temperature; (D) the response curve of the emission intensity at 600nm and temperature; (E) the response curve of the emission intensity at 626nm and temperature; (F) the response curve of the ratio of the emission intensity at 626nm to the emission intensity at 568nm and temperature of the solid-state 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 examples, but is not limited thereto; however, the present invention is not limited to the embodiments described. Experimental methods in the following examples without specifying specific conditions may be selected according to conventional methods and conditions, or according to product specifications.

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

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

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

[0042] (2) 0.10 mmol of acetylene silver precursor, 0.06 mmol of silver (I) benzoate, 0.06 mmol of tris (4-methoxyphenyl) phosphine and 0.02 mmol of tetraethylammonium nitrate were dissolved in 10 ml of dichloromethane and stirred at room temperature for 12 hours to generate a deep red solution. Finally, the reaction mother liquor was concentrated to 3 ml and transferred to a 15x150 cm test tube. 15 ml 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 75.5%.

[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 initially form, which will then gradually dissolve. Stop adding the solution when it becomes clear again, thereby obtaining 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 will quickly form a red precipitate, and continue stirring 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) 0.10 mmol of acetylene silver precursor, 0.06 mmol of silver (I) benzoate, 0.06 mmol of tris (4-methoxyphenyl) phosphine and 0.02 mmol of ammonium nitrate were dissolved in 10 ml of dichloromethane and stirred at room temperature for 12 hours to obtain a deep red solution. Finally, the reaction mother liquor was concentrated to 3 ml and transferred to a 15 x 150 test tube. 15 ml 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 rapidly generates a large amount of red precipitate. Stirring is continued for 6 hours until the AgClO4 crystals completely disappear. The mixture is then filtered and washed with methanol three times. The methanol is then vacuum-evacuated 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 tris(4-methoxyphenyl)phosphine, and 0.02 mmol of potassium nitrate were dissolved in 8 ml of a 3:1 mixed solvent of chloroform and methanol, 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. After one week, red flaky silver metal nanomaterial crystals were obtained, with a crystal yield of 59.5%.

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

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

[0051] (2) 0.10 mmol of acetylene silver precursor, 0.06 mmol of silver (I) benzoate, 0.06 mmol of tris(4-methoxyphenyl)phosphine, and 0.02 mmol of tetramethylammonium nitrate were dissolved in 3 ml 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 15 x 150 test tube, 15 ml of ether was added for interfacial diffusion, and the tube was sealed and kept away from light for 7 days to obtain red bulk 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) 0.2 mmol of AgNO3 was weighed and added to a methanol solution containing 0.1 mmol of 3,6-di-tert-butyl-1,8-diethyl-9H-carbazole. 10 mmol of triethylamine was added dropwise with vigorous stirring. The reaction rapidly produced a large amount of red precipitate. Stirring was continued for 6 hours until all the white silver nitrate crystals disappeared. The mixture was then filtered, washed three times with methanol, and the methanol was removed under vacuum 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 tris(4-methoxyphenyl)phosphine, and 0.02 mmol of potassium nitrate were dissolved in 4 ml of a 3:1 mixture of chloroform and methanol. The mixture was stirred at room temperature for 12 h to obtain a deep red solution. The mother liquor was transferred to a test tube, covered with 3 volumes of n-hexane for interfacial diffusion, and sealed and allowed to stand for 7 days to obtain red bulk silver metal nanomaterial crystals with a crystal yield of 23.4%.

[0055] Example 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 were collected on a Bruker DiffractometerMD2 diffractometer at the BL17B beamline of the National Center for Protein Science (NCPSS) in Shanghai. The data were processed using the BrukerAPEX4 program. The light source wavelength 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 silver nanocluster 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)phosphines, and two nitrates. 3,6-di-tert-butyl-1,8-diethyl-9H-carbazole has two deprotonation modes: two of them remove a hydrogen atom from the ethynyl group and coordinate with the silver atom as a monodentate ligand with a coordination mode of 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 adopt bidentate coordination mode to bridge silver atoms. Benzoate can be divided into two groups: one group of four benzoate is coordinated with two silver atoms. The other group of four benzoate groups coordinates with three silver atoms. Nitrate bridges three silver atoms Six tris(4-methoxyphenyl)phosphines are coordinated with one silver atom through their phosphorus atoms and uniformly surround the Ag. 26 Under the synergistic protection of these four ligands, the silver nanoclusters have 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 300 nm, 310 nm, 362 nm and 396 nm in 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°C to -190°C, 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°C, 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 552 nm, 568 nm, 600 nm and 626 nm showed a linear response to temperature (as shown in Figure 2A). Figure 6 B. Figure 6 C. Figure 6 D and Figure 6 Silver metal nanomaterials also exhibit good ratiometric fluorescence thermometry properties. The ratio of the fluorescence intensity at 626 nm to the fluorescence intensity at 568 nm also has a good linear dependence on temperature (as shown in Figure 2). Figure 6 (as shown in 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 The NO3 is nitrate.

2. A method for preparing silver metal nanomaterials 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-diethynyl-9H-carbazole undergo polymerization 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-diethynyl-9H-carbazole is 3. The method for preparing silver metal nanomaterials according to claim 2, wherein: In step (1), the silver (I) salt is one or a combination of more than one of AgNO3, AgF, AgCl, AgBr, AgI, CF3SO3Ag, AgClO4, AgBF4, AgPF6 and AgSbF6.

4. The method for preparing silver metal nanomaterials according to claim 2, wherein: In step (1), the solvent is one or a combination of more than one of water, chloroform, dichloromethane, acetonitrile, ethanol or methanol.

5. The method for preparing silver metal nanomaterials according to claim 2, wherein: 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 method for preparing silver metal nanomaterials according to claim 2, wherein: In step (1), the molar ratio of the silver (I) salt to 3,6-di-tert-butyl-1,8-diethynyl-9H-carbazole is 2-2.5:

1.

7. The method for preparing silver metal nanomaterials according to claim 2, wherein: 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 method for preparing silver metal nanomaterials according to claim 2, wherein: 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; 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 claim 1, 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 claim 1 in a ratiometric fluorescence thermometer.

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