Silver cluster metal nanomaterial, preparation method and application thereof

Abstract

The invention provides a novel metal nano-material, and particularly provides a silver cluster metal nano-material, a preparation method and application of the silver cluster metal nano-material. In a wide temperature range, the emission intensity at the 545nm position and the emission intensity at the 505nm position have a one-to-one correspondence relationship. The characteristic shows the excellent ratio fluorescence temperature measurement performance of the material. The silver cluster metal nanometer material can be used as a nanometer fluorescence thermometer, and has good application potential in the high-tech fields of biomedicine (such as cell metabolism, pathology, medical imaging and drug delivery), electronic element manufacturing and the like.

Description

Technical Field

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

[0002] Temperature is one of the most basic parameters in nature. Reliable, fast and accurate temperature measurement is indispensable in many fields. Based on the principles of volume change (such as mercury thermometer), mechanical displacement (such as bimetallic thermometer), potential difference (such as thermocouple thermometer), conductivity (such as thermistor thermometer) and infrared radiation (such as thermal imaging thermometer), people have developed various temperature measurement tools to meet the needs of different scenarios in production and life.

[0003] Fluorescence thermometry is an emerging temperature measurement method that determines the temperature by detecting the fluorescence signal of thermosensitive fluorescent materials. Compared with traditional thermometers, fluorescence thermometry has the advantages of remote temperature measurement, high sensitivity, submicroscale resolution, fast response and non-contact temperature measurement. Fluorescence thermometry has great advantages in the temperature measurement of micro-objects such as biomedicine, biosensing and nano-scale devices. The core of fluorescence thermometry is thermoluminescent color-changing materials. When the temperature changes, the electronic structure or molecular configuration inside such materials will change, resulting in changes in fluorescence signals. The optical indicators for detecting thermoluminescent color change phenomena include fluorescence emission position, fluorescence emission lifetime and fluorescence emission intensity. Among them, the emission intensity can be measured quickly and accurately by photon counting, so it has been widely studied.

[0004] Silver nanoclusters in metal nanomaterials are ultra-small materials composed of several to hundreds of silver atoms, with particle sizes usually ranging from 1 nanometer to 10 nanometers. The metal interactions in the core and the vibration and rotation behaviors of the protective ligands are extremely susceptible to temperature changes. These tiny structural changes will significantly affect their photophysical properties, causing silver clusters to often exhibit thermoluminescence color change characteristics. Therefore, silver nanoclusters are considered to be an ideal type of fluorescent temperature measurement material.

[0005] Although some studies have reported silver clusters with thermoluminescent color-changing properties, and the fluorescence intensity of some silver clusters shows good dependence on temperature changes, the number of such materials is still limited overall. In particular, research reports on nanosilver clusters with dual or multiple emission characteristics and the potential for ratiometric fluorescence thermometry are relatively scarce. Summary of the invention

[0006] The present invention aims to provide a novel metal nanomaterial, which can be applied to nanofluorescence thermometers and has good application prospects in high-tech fields such as biomedicine (such as cell metabolism, pathology, medical imaging and drug delivery, etc.) and electronic component manufacturing.

[0007] The first object of the present invention is to provide a silver cluster metal nanomaterial, the molecular formula of which is Ag 26 (H2decz)2(Hdecz)8(PhCOO)8(P(PhF)3)6;

[0008] The "H2decz" is The "Hdecz" is The PhCOO is benzoate The P(PhF)3 is tri(4-fluorophenyl)phosphine

[0009] According to the preferred embodiment of the present invention, the above silver cluster metal nanomaterial can be prepared by the following method

[0010] (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;

[0011] (2) dissolving the silver acetylene precursor, silver (I) benzoate and tri(4-fluorophenyl)phosphine in a solvent to prepare the metal nanomaterial through a self-assembly reaction;

[0012] Wherein, the structural formula of the 3,6-di-tert-butyl-1,8-diethyl-9H-carbazole is

[0013] 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.

[0014] 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.

[0015] 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.

[0016] Preferably according to the present invention, in step (1), the molar ratio of the silver (I) salt to the 3,6-di-tert-butyl-1,8-diethyl-9H-carbazole is 2-2.5:1.

[0017] Preferably according to the present invention, in step (2), the solvent may be one or a combination of more than one of 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 ratio of the acetylenic silver precursor, silver (I) benzoate and tri(4-fluorophenyl)phosphine is 9-11:7-9:5-7, and the optimal reaction molar ratio is 10:8:6.

[0019] Preferably, according to the present invention, in step (2), the reaction conditions can be either room temperature stirring or low temperature solvent heating.

[0020] The second object of the invention is to provide a crystal form of a silver cluster metal nanomaterial, wherein the unit cell parameters of the crystal form are: α(deg)=99.088(3); β(deg)=95.676(2); γ(deg)=117.691(2).

[0021] The third object of the invention is to provide a method for preparing a metal nanomaterial, which can be the method for preparing the metal nanomaterial described in this article.

[0022] A fourth object of the invention is to provide an application of the above-mentioned silver cluster metal nanomaterial in a ratio fluorescence thermometer.

[0023] 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.

[0024] Unless otherwise specified, the reagents and raw materials used in the present invention are commercially available.

[0025] The technical features and beneficial effects of the present invention are as follows:

[0026] 1. The synthesis method of the silver cluster metal nanomaterial of the present invention is simple and mild, and the product can be easily purified by volatilization or diffusion treatment. This synthesis method not only reduces environmental impact, but also improves production efficiency and has significant economic benefits.

[0027] 2. The silver cluster metal nanomaterials described in the present invention have an atomically precise structure and can be used to conduct in-depth structure-activity relationship research in combination with theoretical calculations.

[0028] 3. The silver cluster metal nanomaterials of the present invention show good potential in fluorescence temperature measurement. Under 365nm excitation, the four maximum emission peaks in its solid-state temperature curve, namely 605nm, 640nm, 505nm and 545nm, all show obvious temperature dependence. The emission intensity at 545nm, 605nm and 640nm shows a good linear response relationship with temperature, while at 505nm, the emission intensity shows a significant exponential response relationship with temperature.

[0029] 4. The silver cluster metal nanomaterials described in the present invention have good ratio fluorescence temperature measurement potential. At low temperatures, the silver cluster metal nanomaterials change from single emission to triple emission. While its maximum emission peak red-shifts from 605nm to 640nm, two new emission peaks appear at 505nm and 545nm. Between 30℃ and -190℃, the ratio of the emission intensity at 545nm to the emission intensity at 505nm corresponds one to one with the temperature. This ratio temperature measurement characteristic can greatly improve the sensitivity and accuracy of temperature measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a single crystal structure diagram of silver cluster metal nanomaterials. For simplicity, hydrogen atoms and the tert-butyl group on 3,6-di-tert-butyl-1,8-diethyl-9H-carbazole are omitted.

[0031] Figure 2 This is the UV-visible absorption curve of silver cluster metal nanomaterials in dichloromethane solution.

[0032] Figure 3 is the excitation of silver cluster metal nanomaterials in the solid state (λ em = 605nm, dotted line) and emission (λ ex =365nm, solid line) curve.

[0033] Figure 4 is the maximum emission peak of silver cluster metal nanomaterials in the solid state (λ max =605nm) lifetime decay curve.

[0034] Figure 5 This is the temperature-dependent fluorescence curve of silver cluster metal nanomaterials in the solid state, with an excitation wavelength of 365nm.

[0035] Figure 6 The emission intensity of solid silver cluster metal nanomaterials at different emission wavelengths varies with temperature under 365nm ultraviolet light excitation; (A) the response curve of emission intensity and temperature at 640nm; (B) the response curve of emission intensity and temperature at 605nm; (C) the response curve of emission intensity and temperature at 545nm; (D) the response curve of emission intensity and temperature at 505nm.

[0036] Figure 7 This is the response curve of the ratio of the emission intensity at 545nm to the emission intensity at 505nm of the solid silver cluster metal nanomaterial under 365nm ultraviolet light excitation and temperature. DETAILED DESCRIPTION

[0037] 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; however, the present invention is not limited to the described examples. The experimental methods in the following examples without specifying specific conditions shall be selected according to conventional methods and conditions, or according to the product instructions.

[0038] The 3,6-di-tert-butyl-1,8-diethyl-9H-carbazole involved in the present invention is prepared according to Dalton Trans. 2017, 46, 4696-4710, and other reagents and solvents can be obtained commercially.

[0039] Example 1: Synthesis method of silver cluster metal nanomaterials in the present invention

[0040] (1) Weigh 1 equivalent of Ag2O and add it to 25% ammonia water, stir until it is clear, and obtain a silver ammonia solution. Dissolve 1 equivalent of 3,6-di-tert-butyl-1,8-diethyl-9H-carbazole in 1,4-dioxane and add it dropwise to the silver ammonia solution under vigorous stirring. The reaction quickly generates a red precipitate, and the stirring is continued for 6 hours. Then filter, wash with water 3 times, and vacuum dry the water to obtain a deep red silver acetylene precursor with a yield of 82.7%.

[0041] (2) 10 equivalents of acetylene silver precursor, 8 equivalents of silver (I) benzoate and 6 equivalents of tri(4-fluorophenyl)phosphine were dissolved in dichloromethane and stirred at room temperature for 12 h to obtain a deep red solution. The mother liquor was transferred to a test tube, 3 volumes of n-hexane were spread on it for interfacial diffusion, and the tube was sealed and allowed to stand for 5 days to obtain red blocky silver cluster metal nanomaterial crystals with a crystal yield of 73.5%.

[0042] Example 2: Synthesis method of silver cluster metal nanomaterials in the present invention

[0043] (1) Weigh 2 equivalents of AgNO3, dissolve it in water, and add ammonia water with a mass concentration of 25% dropwise. The system first generates a gray precipitate, which then slowly dissolves. When the system becomes clear again, stop adding drops to obtain a silver ammonia solution. Dissolve 1 equivalent of 3,6-di-tert-butyl-1,8-diethyl-9H-carbazole in 1,4-dioxane and add it dropwise to the silver ammonia solution under vigorous stirring. The reaction quickly generates a red precipitate and continues stirring for 6 hours. Then filter, wash with water 3 times, and vacuum dry the water to obtain a red silver acetylene precursor with a yield of 83.5%.

[0044] (2) Dissolve 10 equivalents of acetylene silver precursor, 8 equivalents of silver (I) benzoate and 6 equivalents of tri(4-fluorophenyl)phosphine in chloroform and stir at room temperature for 12 hours to obtain a deep red solution. The reaction mother liquor is kept away from light and evaporated for one week to obtain red flaky silver cluster metal nanomaterial crystals with a crystal yield of 76.2%.

[0045] Example 3: Synthesis method of silver cluster metal nanomaterials in the present invention

[0046] (1) Weigh 2 equivalents of AgNO3 and add them to a methanol solution containing 1 equivalent of 3,6-di-tert-butyl-1,8-diethyl-9H-carbazole. Add 10 equivalents 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%.

[0047] (2) 10 equivalents of acetylene silver precursor, 8 equivalents of silver (I) benzoate and 6 equivalents of tri(4-fluorophenyl)phosphine were dissolved in N,N-dimethylacetamide and stirred at room temperature for 12 hours to obtain a deep red solution. The mother liquor was transferred to a test tube, 3 volumes of ether were spread on it for interfacial diffusion, and the tube was sealed and allowed to stand for 7 days to obtain red blocky silver cluster metal nanomaterial crystals with a crystal yield of 40.5%.

[0048] Example 4: Synthesis method of silver cluster metal nanomaterials in the present invention

[0049] (1) Weigh 2 equivalents of AgSO3CF3 and 1 equivalent of 3,6-di-tert-butyl-1,8-diethyl-9H-carbazole, add dichloromethane, and sonicate to dissolve all reactants. Add 10 equivalents of triethylamine dropwise to the system, and the reaction solution changes from light yellow to dark red. Continue stirring for 6 hours. Remove all dichloromethane and excess triethylamine. Wash with methanol 3 times, filter, and vacuum dry the methanol to obtain a red silver acetylene precursor with a yield of 77.8%.

[0050] (2) 10 equivalents of acetylene silver precursor, 8 equivalents of silver (I) benzoate and 6 equivalents of tri(4-fluorophenyl)phosphine were dissolved in dichloromethane and stirred at room temperature for 12 h to obtain a deep red solution. The mother liquor was transferred to a test tube, 3 volumes of n-hexane were spread on it for interfacial diffusion, and the tube was sealed and allowed to stand for 5 days to obtain red blocky silver cluster metal nanomaterial crystals with a crystal yield of 34.5%.

[0051] Example 5: Synthesis method of silver cluster metal nanomaterials in the present invention

[0052] (1) Weigh 1 equivalent of 3,6-di-tert-butyl-1,8-diethyl-9H-carbazole and 2 equivalents of sodium hydroxide, add methanol, and sonicate until all the sodium hydroxide is dissolved. Then add 2 equivalents of AgBF4, and a large amount of red precipitate is quickly produced. Continue stirring for 6 hours. Filter, wash with methanol 3 times, and vacuum dry the methanol to obtain a red silver acetylene precursor with a yield of 80.1%.

[0053] (2) 10 equivalents of acetylene silver precursor, 8 equivalents of silver (I) benzoate and 6 equivalents of tri(4-fluorophenyl)phosphine were dissolved in dichloromethane and stirred at room temperature for 12 h to obtain a deep red solution. The mother liquor was transferred to a test tube, 3 volumes of n-hexane were spread on it for interfacial diffusion, and the tube was sealed and allowed to stand for 5 days to obtain red blocky silver cluster metal nanomaterial crystals with a crystal yield of 10.0%.

[0054] Example 6: Structural Characterization

[0055] The crystal obtained in Example 1 was used as an example to characterize the single crystal structure. 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. Molecular formula is C 404 H 344 Ag 26 F 18 N 10 O 16 P6. Other relevant data are shown in Table 1:

[0056] Table 1

[0057]

[0058] like Figure 1 As shown in Figure 2, X-ray single crystal diffraction experiments show that the core of the nanocluster is composed of 26 silver atoms. 26 There are ten 3,6-di-tert-butyl-1,8-diethyl-9H-carbazole ligands, eight benzoate ligands and six tri(4-fluorophenyl)phosphine ligands distributed on the cluster. Two of the 3,6-di-tert-butyl-1,8-diethyl-9H-carbazole ligands 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. 2 :η 1 :η 1 The remaining eight 3,6-di-tert-butyl-1,8-diethyl-9H-carbazole ligands remove the hydrogen atoms on the two alkynyl groups and coordinate with the silver atom as bidentate ligands. There are three coordination modes: ①μ3-η 1 :η 1 :η 1 ,μ2-η 1 :η 1 ②μ2-η 2 :η 1 ,μ1-η 1 ③μ3-η 1 :η 1 :η 1 ,μ3-η 1 :η 1 :η 1 Benzoate groups are bound to silver atoms by bidentate coordination. According to different coordination modes, these benzoate groups can be divided into two groups: one group of four benzoate groups is coordinated with three silver atoms. The other group of four benzoate groups coordinates with two silver atoms. The tri(4-fluorophenyl)phosphine (P(PhF)3) ligand coordinated with a silver atom through an Ag-P bond to further stabilize the cluster structure.

[0059] Example 7: Photophysical testing

[0060] The UV-Vis absorption spectrum of the material was measured on a Perkin-Elmer Lambda 365 UV-Vis spectrophotometer. The silver cluster metal nanomaterials in dichloromethane solution mainly exhibited four UV absorption peaks, which were located at 300nm, 310nm, 362nm and 395nm ( Figure 2 ).

[0061] The excitation and emission spectra and emission lifetime of the material were characterized by Edinburgh Analytical Instruments (FLS920 fluorescence spectrometer). In solution, the silver cluster metal nanomaterials hardly emit light, but in powder state, they can emit orange-red light. At room temperature, the maximum emission peak of its solid powder is located at 605nm ( Figure 3 ), the emission lifetime is 57.7ns( Figure 4 ). The variable temperature fluorescence experiment shows that Ag 26 It has good thermoluminescence color change properties in the solid state. When the temperature drops from 30℃ to -190℃, the silver cluster metal nanomaterial changes from single emission to triple emission. Its maximum emission peak red-shifts from 605nm to 640nm, and two new emission peaks appear at 505nm and 545nm ( Figure 5). These emission peaks show obvious temperature dependence. The emission intensity at 640nm, 605nm and 545nm shows a good linear response relationship with temperature ( Figure 6 At 505 nm, the emission intensity shows a significant exponential response relationship with temperature ( Figure 6 In addition, the silver cluster metal nanomaterial also exhibits ratiometric fluorescence thermometry potential. Between 30℃ and -190℃, there is a clear correspondence between the ratio of the emission intensity at 545nm to the emission intensity at 505nm and the temperature ( Figure 7 ).

Claims

1. A silver cluster metal nanomaterial, characterized in that: The molecular formula of the metal nanomaterial is Ag 26 (H2decz)2(Hdecz)8(PhCOO)8(P(PhF)3)6; Wherein, the "H2decz" is The "Hdecz" is The PhCOO is benzoate The P(PhF)3 is tri(4-fluorophenyl)phosphine 2. The silver cluster metal nanomaterial according to claim 1, characterized in that: The 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 (I) benzoate and tri(4-fluorophenyl)phosphine in a solvent to prepare the 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 cluster 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 or AgSbF6.

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

1.

7. The silver cluster metal nanomaterial according to claim 2, characterized in that: In step (2), the solvent is one or a combination of more than one of dichloromethane, chloroform, acetonitrile, 1,2-dichloroethane, dimethyl sulfoxide, N,N-dimethylformamide, and N,N-dimethylacetamide.

8. The silver cluster metal nanomaterial according to claim 2, characterized in that: In step (2), the reaction ratio of the acetylenic silver precursor, silver (I) benzoate and tri(4-fluorophenyl)phosphine is 9-11:7-9:5-7, and the optimal reaction molar ratio is 10:8:

6.

9. A crystal form of the silver cluster metal nanomaterial according to any one of claims 1 to 8, characterized in that: Crystal cell number α(deg)=99.088(3); β(deg)=95.676(2); γ(deg)=117.691(2).

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

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