Ptag alloy nanocluster, and preparation method and application thereof

Abstract

This invention discloses a PtAg alloy nanocluster, its preparation method, and its application, belonging to the field of nanomaterials technology. This invention prepares PtAg alloy nanoclusters, namely Pt1Ag. 14 (DPPB)3(C6F5S)6 has an icosahedral metallic core composed of one platinum atom and twelve silver atoms. Following this, Pt1Ag... 12 The metallic core is first covered by two Ag(C6F5S)3 studs to form a composite structure, and then surrounded by three DPPB ligands to form an integral structure. The Pt1Ag prepared in this invention... 14 (DPPB)3(C6F5S)6 nanoclusters exhibit good fluorescence response to Hcy, and Pt1Ag in the presence of oxygen... 14 (DPPB)3(C6F5S)6 exhibits better Hcy recognition under long-wavelength excitation and higher contrast compared to single-photon fluorescence.

Description

Technical Field

[0001] This invention relates to the field of nanomaterials technology, specifically to a PtAg alloy nanocluster, its preparation method, and its application. Background Technology

[0002] Metal nanoclusters (MNCs) are ultrasmall particles with unique photoelectric and chemical properties, exhibiting a wide range of material characteristics such as fluorescence, chirality, magnetism, catalysis, electrochemistry, electroluminescence, and electrochemiluminescence. In recent years, leading chemists in many fields have conducted extensive and in-depth research on metal nanoclusters with photoluminescent effects. Metal nanoclusters with strong fluorescence are beginning to be used as probe molecules for the detection of specific biological molecules.

[0003] Homocysteine ​​(HCy) is an amino acid whose levels in the human body are associated with the occurrence of cardiovascular diseases, stroke, and arteriosclerosis. Therefore, the detection of homocysteine ​​is of great significance in clinical diagnosis. Cysteine ​​(Cys) is also a key amino acid, playing an important role in redox homeostasis, protein function, and metabolism. In laboratory testing, due to the lack of more reliable and convenient testing methods, distinguishing between homocysteine ​​(Cys), homocysteine ​​(Hcy), and glutathione (GSH) in complex redox environments within the same detection time remains a significant and challenging task. Furthermore, visualizing the results of dynamic biological events occurring in vivo and in vitro during real-time monitoring by probe detection, thereby accurately reflecting temporal and spatial processes, is also of great importance. Therefore, this invention provides a PtAg alloy nanocluster, its preparation method, and its application. Summary of the Invention

[0004] This invention provides a Pt / Ag alloy nanocluster, its preparation method, and its application, effectively solving the technical problem of not being able to effectively distinguish between common cysteine ​​(Cys), homocysteine ​​(Hcy), and glutathione (GSH) within the same detection time in complex redox environments. It also provides a strongly fluorescent Pt1Ag that enhances Hcy detection behavior under oxygen conditions. 14 (DPPB)3(C6F5S)6 cluster.

[0005] The first objective of this invention is to provide a PtAg alloy nanocluster with the general molecular formula Pt1Ag. 14 (DPPB)3(C6F5S)6, wherein DPPB is bis(diphenylphosphine)butane and C6F5S is pentafluorothiophenol.

[0006] The second objective of this invention is to provide a method for preparing PtAg alloy nanoclusters, comprising the following steps:

[0007] Tetraoctylammonium bromide was dissolved in a mixed solution of dichloromethane and methanol. A silver source aqueous solution was added and stirred. A platinum source aqueous solution was added and stirred. Then, 2,3,4,5,6-pentafluorothiophenol and 1,4-bisdiphenylbutane were added sequentially to carry out the initial reaction to obtain a mixed solution. A methanol solution of tert-butylamine borane was added to the mixed solution to carry out a one-pot reduction reaction to obtain a crude product. After crystallization, PtAg alloy nanoclusters were obtained.

[0008] In a preferred embodiment, the ratio of tetra-n-octylammonium bromide, silver source, platinum source, 2,3,4,5,6-pentafluorothiophenol, 1,4-bis(diphenylbutane) and tert-butylamine borane is 2 mg:4.59 μmol:0.49 μmol:1 μL:1 mg:4 mg.

[0009] In a preferred embodiment, the silver source is silver nitrate.

[0010] In a preferred embodiment, the platinum source is chloroplatinic acid.

[0011] In a preferred embodiment, the one-pot reduction reaction takes 10 to 12 hours.

[0012] In a preferred embodiment, the initial reaction time is 15 to 30 minutes.

[0013] As a preferred embodiment, before crystallization, the crude product is dissolved in dichloromethane, mixed with ethanol and shaken until homogeneous, ultrasonically cleaned, centrifuged, and the precipitate is collected. The precipitate is then dissolved in dichloromethane and coated onto a TLC silica gel plate for purification.

[0014] A third objective of this invention is to provide an application of the aforementioned PtAg alloy nanoclusters in the detection of homocysteine.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0016] This invention provides a PtAg alloy nanoclusters, its preparation method, and its application. Tetra-n-octylammonium bromide is dissolved in a mixed solution of dichloromethane and methanol. A silver source aqueous solution is added and stirred. A platinum source aqueous solution is added and stirred again. Then, 2,3,4,5,6-pentafluorothiophenol and 1,4-bisdiphenylbutane are added sequentially for an initial reaction to obtain a mixed solution. A methanol solution of tert-butylamine borane is added to the mixed solution for a one-pot reduction reaction to obtain a crude product. The product is then crystallized to obtain PtAg alloy nanoclusters.

[0017] The PtAg alloy nanoclusters prepared by this invention, namely Pt1Ag 14 (DPPB)3(C6F5S)6 has an icosahedral metallic core composed of one platinum atom and twelve silver atoms. Following this, Pt1Ag... 12 The metallic core is first covered by two Ag(C6F5S)3 studs to form a composite structure, and then surrounded by three DPPB ligands to form an integral structure. The Pt1Ag prepared in this invention... 14 (DPPB)3(C6F5S)6 nanoclusters exhibit good fluorescence response to Hcy, and Pt1Ag in the presence of oxygen... 14 (DPPB)3(C6F5S)6 exhibits better Hcy recognition under long-wavelength excitation and higher contrast compared to single-photon fluorescence. Attached Figure Description

[0018] Figure 1 Pt1Ag prepared for this invention 14 (DPPB)3(C6F5S)6、Pt1Ag 14 (DPPB)3(C6F5S)6-cyclobutanesulfone molecule and Pt1Ag 14 Summary structure diagram of (C6HF5S)6(DPPB)3-(C4H9O2NS)-(CH2Cl2);

[0019] Figure 2 Pt1Ag prepared for this invention 14 Structural breakdown diagram of (DPPB)3(C6F5S)6;

[0020] Figure 3 Orange-yellow rhomboid block-shaped Pt1Ag prepared in Example 1 of this invention 14 UV-Vis spectrum of (DPPB)3(C6F5S)6 single crystal (dissolved in CH2Cl2);

[0021] Figure 4 Pt1Ag prepared in Example 1 of this invention 14 ESI-MS data of (DPPB)3(C6F5S)6;

[0022] Figure 5 Pt1Ag prepared in Example 1 of this invention 14 Excitation and emission spectra of (DPPB)3(C6F5S)6;

[0023] Figure 6 Pt1Ag prepared in Example 1 of this invention 14 Solid-state fluorescence lifetime plot of (DPPB)3(C6F5S)6;

[0024] Figure 7 Pt1Ag prepared in Example 1 of this invention 14 Fluorescence lifetime plot of (DPPB)3(C6F5S)6 (in CH2Cl2 solution);

[0025] Figure 8 Pt1Ag prepared in Example 1 of this invention 14 Fluorescence response diagram of (DPPB)3(C6F5S)6 to Hcy;

[0026] Figure 9 Pt1Ag prepared in Example 1 of this invention 14 The change in fluorescence intensity of (DPPB)3(C6F5S)6 after oxygen is introduced;

[0027] Figure 10 Pt1Ag prepared in Example 1 of this invention 14 Fluorescence response of (DPPB)3(C6F5S)6 to Hcy in an oxygen atmosphere;

[0028] Figure 11 Pt1Ag prepared in Example 1 of this invention 14 (DPPB)3(C6F5S)6 specifically recognizes Hcy and Cys plots;

[0029] Figure 12 To improve the Pt1Ag prepared in Example 1 of this invention with increasing oxygen content 14 Three-photon fluorescence intensity variation of (DPPB)3(C6F5S)6;

[0030] Figure 13 To improve the Pt1Ag prepared in Example 1 of this invention with increasing Hcy concentration 14 (DPPB)3(C6F5S)6 tri-photon fluorescence intensity variation graph;

[0031] Figure 14 Pt1Ag prepared in Example 1 of this invention 14 Three-photon absorption cross section of (DPPB)3(C6F5S)6;

[0032] Figure 15 To increase Hcy in an oxygen atmosphere for the Pt1Ag prepared in Example 1 of this invention 14 The effect of (DPPB)3(C6F5S)6 three-photon fluorescence intensity diagram;

[0033] Figure 16 To increase Hcy in an oxygen atmosphere for the Pt1Ag prepared in Example 1 of this invention 14 The effect of the three-photon absorption cross section of (DPPB)3(C6F5S)6. Detailed Implementation

[0034] To enable those skilled in the art to better understand and implement the technical solutions of this invention, the invention will be further described below with reference to specific embodiments and accompanying drawings. However, the embodiments described are not intended to limit the invention. Unless otherwise specified, the following test methods and detection methods are conventional methods; unless otherwise specified, the reagents and raw materials are commercially available.

[0035] To address the technical problems of existing technologies that cannot distinguish between common cysteine ​​(Cys), homocysteine ​​(Hcy), and glutathione (GSH) within the same detection time, and that cannot visualize the results of dynamic biological events occurring in vivo and in vitro during real-time monitoring at the probe detection site, thus failing to accurately reflect temporal and spatial processes, this invention provides a PtAg alloy nanoclusters, its preparation method, and its application. Tetra-n-octylammonium bromide is dissolved in a mixed solution of dichloromethane and methanol. A silver source aqueous solution is added and stirred. A platinum source aqueous solution is added and stirred. Then, 2,3,4,5,6-pentafluorobenzenethiophenol and 1,4-bisdiphenylbutane are added sequentially for an initial reaction to obtain a mixed solution. A methanol solution of tert-butylamine borane is added to the mixed solution for a one-pot reduction reaction to obtain a crude product. Crystallization yields PtAg alloy nanoclusters.

[0036] Pt1Ag prepared by this invention 14 (DPPB)3(C6F5S)6 nanoclusters exhibit good fluorescence response to Hcy, and Pt1Ag in the presence of oxygen... 14 (DPPB)3(C6F5S)6 exhibits better Hcy recognition under long-wavelength excitation and higher contrast compared to single-photon fluorescence.

[0037] The effects are explained below with reference to specific embodiments.

[0038] Example 1

[0039] A method for preparing PtAg alloy nanoclusters includes the following steps:

[0040] Highly fluorescent Pt1Ag was prepared by a one-pot reduction synthesis method. 14 (DPPB)3(C6F5S)6 nanoclusters:

[0041] S1, Dissolve 100 mg tetra-n-octylammonium bromide in a mixed solution of 15 mL dichloromethane and 5 mL methanol, shake well to obtain a homogeneous solution; Dissolve 50 mg AgNO3 in 2 mL H2O, add it to the homogeneous solution, stir for 5 min, and the solution changes from colorless and transparent to a pale yellow clear solution.

[0042] S2, add 10 mg of chloroplatinic acid aqueous solution to the above clear pale yellow solution, stir for 10 min, the solution gradually turns into a turbid yellowish-brown solution. After 20 min, add 50 μL of 2,3,4,5,6-pentafluorothiophenol to the turbid yellowish-brown solution, the solution slowly turns dark green. After 15 min, add 50 mg of 1,4-bis(diphenylbutane), the solution gradually changes from turbid yellowish-brown to a pale greenish-brown turbid solution. Continue the initial reaction for another 30 min to obtain a mixed solution. Add 200 mg of tert-butylamine borane (C4H) 11 BN) was dissolved in 2 mL of CH3OH and poured into the above mixed solution. The reaction was continued for 12 h. The solution system slowly changed from black to a clear orange-yellow liquid and slowly produced orange-yellow fluorescence. The solution was centrifuged at 11000 rpm for 3 min to remove the black impurity precipitate and obtain an orange-yellow supernatant.

[0043] S3, the orange-yellow supernatant was evaporated to dryness to obtain an orange-yellow crude product. This product was dissolved in 2 mL of dichloromethane, followed by the addition of 2 mL of ethanol and vortexing. The mixture was then ultrasonically washed for 3 min until an orange-yellow precipitate formed. The precipitate was centrifuged, washed, and the orange-yellow powder was collected. This powder was dissolved in dichloromethane and coated onto a TLC silica gel plate for purification (toluene / cyclopentane = 1:1). Crystallization and diffusion at room temperature using a dichloromethane / methanol mixture yielded orange-yellow transparent rhombic single crystals, i.e., Pt1Ag. 14 (DPPB)3(C6F5S)6 nanoclusters.

[0044] Example 2

[0045] A method for preparing PtAg alloy nanoclusters includes the following steps:

[0046] Highly fluorescent Pt1Ag was prepared by a one-pot reduction synthesis method. 14 (DPPB)3(C6F5S)6 nanoclusters:

[0047] S1, Dissolve 100 mg tetra-n-octylammonium bromide in a mixed solution of 15 mL dichloromethane and 5 mL methanol, shake well to obtain a homogeneous solution; Dissolve 50 mg AgNO3 in 2 mL H2O, add it to the homogeneous solution, stir for 5 min, and the solution changes from colorless and transparent to a pale yellow clear solution.

[0048] S2, add 10 mg of chloroplatinic acid aqueous solution to the above clear pale yellow solution, stir for 10 min, the solution gradually turns into a turbid yellowish-brown solution. After 20 min, add 45 μL of 2,3,4,5,6-pentafluorothiophenol to the turbid yellowish-brown solution, the solution slowly turns dark green. After 15 min, add 45 mg of 1,4-bis(diphenylbutane), the solution gradually changes from turbid yellowish-brown to a pale greenish-brown turbid solution. Continue the initial reaction for another 15 min to obtain a mixed solution. Add 180 mg of tert-butylamine borane (C4H) 11 BN) was dissolved in 2 mL of CH3OH and poured into the above mixed solution. The reaction was continued for 10 h. The solution system slowly changed from black to a clear orange-yellow liquid and slowly produced orange-yellow fluorescence. The solution was centrifuged at 11000 rpm for 3 min to remove the black impurity precipitate and obtain an orange-yellow supernatant.

[0049] S3, the orange-yellow supernatant was evaporated to dryness to obtain an orange-yellow crude product. This product was dissolved in 2 mL of dichloromethane, followed by the addition of 2 mL of ethanol and vortexing. The mixture was then ultrasonically washed for 3 min until an orange-yellow precipitate formed. The precipitate was centrifuged, washed, and the orange-yellow powder was collected. This powder was dissolved in dichloromethane and coated onto a TLC silica gel plate for purification (toluene / cyclopentane = 1:1). Crystallization and diffusion at room temperature using a dichloromethane / methanol mixture yielded orange-yellow transparent rhombic single crystals, i.e., Pt1Ag. 14 (DPPB)3(C6F5S)6 nanoclusters.

[0050] Example 3

[0051] A method for preparing PtAg alloy nanoclusters includes the following steps:

[0052] Highly fluorescent Pt1Ag was prepared by a one-pot reduction synthesis method. 14 (DPPB)3(C6F5S)6 nanoclusters:

[0053] S1, Dissolve 100 mg tetra-n-octylammonium bromide in a mixed solution of 15 mL dichloromethane and 5 mL methanol, shake well to obtain a homogeneous solution; Dissolve 50 mg AgNO3 in 2 mL H2O, add it to the homogeneous solution, stir for 5 min, and the solution changes from colorless and transparent to a pale yellow clear solution.

[0054] S2, add 10 mg of chloroplatinic acid aqueous solution to the above clear pale yellow solution, stir for 10 min, the solution gradually turns into a turbid yellowish-brown solution. After 20 min, add 55 μL of 2,3,4,5,6-pentafluorothiophenol to the turbid yellowish-brown solution, the solution slowly turns dark green. After 15 min, add 55 mg of 1,4-bis(diphenylbutane), the solution gradually changes from turbid yellowish-brown to a pale greenish-brown turbid solution. Continue the initial reaction for another 20 min to obtain a mixed solution. Add 220 mg of tert-butylamine borane (C4H) 11 BN) was dissolved in 2 mL of CH3OH and poured into the above mixed solution. The reaction was continued for 11 h. The solution system slowly changed from black to a clear orange-yellow liquid and slowly produced orange-yellow fluorescence. The solution was centrifuged at 11000 rpm for 3 min to remove the black impurity precipitate and obtain an orange-yellow supernatant.

[0055] S3, the orange-yellow supernatant was evaporated to dryness to obtain an orange-yellow crude product. This product was dissolved in 2 mL of dichloromethane, followed by the addition of 2 mL of ethanol and vortexing. The mixture was then ultrasonically washed for 3 min until an orange-yellow precipitate formed. The precipitate was centrifuged, washed, and the orange-yellow powder was collected. This powder was dissolved in dichloromethane and coated onto a TLC silica gel plate for purification (toluene / cyclopentane = 1:1). Crystallization and diffusion at room temperature using a dichloromethane / methanol mixture yielded orange-yellow transparent rhombic single crystals, i.e., Pt1Ag. 14 (DPPB)3(C6F5S)6 nanoclusters.

[0056] Regarding the Pt1Ag prepared above 14 The properties of the (DPPB)3(C6F5S)6 nanoclusters were tested, and the specific process and results are as follows:

[0057] I. To verify the Pt1Ag prepared in this invention 14 The fluorine-containing ligands of (DPPB)3(C6F5S)6 have the ability to adsorb oxygen-containing molecules. This invention also synthesized Pt1Ag. 14 (C6F5S)6(DPPB)3@(C4H8O2S) nanoclusters and Pt1Ag 14 The (C6HF5S)6(DPPB)3-(C4H9O2NS)-(CH2Cl2) nanoclusters are as follows:

[0058] 1. Contains orange-red rhombic Pt1Ag containing hydrogen peroxide. 14 Synthesis of (DPPB)3(C6F5S)6@(C4H8O2S) nanoclusters: purified Pt1Ag 14(C6HF5S)6(DPPB)3 was dissolved in 4 mL of dichloromethane and concentrated to a long single crystal concentration. 1 mL of sulfolane solvent was added. The mixture was shaken well and filtered to remove particulate impurities. The pure orange-yellow Pt1Ag was obtained. 14 The concentrated stock solution of (C6F5S)6(DPPB)3@(C4H8O2S) was crystallized with dichloromethane / methanol to obtain orange-yellow, well-formed rhombic single crystals.

[0059] 2.Pt1Ag 14 Synthesis of (C6HF5S)6(DPPB)3-(C4H9O2NS)-(CH2Cl2) nanoclusters

[0060] Pt1Ag containing homocysteine ​​molecules (Hcy) 14 Synthesis of (C6HF5S)6(DPPB)3@(C4H9O2NS) nanoclusters: Pt1Ag-containing nanoclusters were synthesized... 14 A concentrated solution of the crude product (C6HF5S)6(DPPB)3 nanoclusters was loaded onto a TLC silica gel plate for purification (toluene / cyclopentane = 1:1). The purified, orange-red Pt1Ag after TLC was then purified. 14 (C6HF5S)6(DPPB)3 was diffuse-crystallized from dichloromethane / methanol at room temperature (25°C) to obtain bulk orange-red single crystals. Two to three weeks later, the bulk red single crystals were extracted and impregnated in a freshly prepared mixed solution (the mixed solution was first composed of 2 ml of ultrapure water and 2 ml of acetonitrile, in which 20 mg of homocysteine ​​Hcy was dissolved).

[0061] The molecule of homocysteine ​​(Hcy) contains a carboxyl group, which is an oxygen-containing functional group. The Pt1Ag prepared above... 14 The expression (C6F5S)6(DPPB)3@(C4H8O2S) indicates that the oxygen atom of sulfolane and the F atom in the pentafluorobenzenethiophenol ligand form an oxyfluorine bond. Similarly, Pt1Ag 14 The single-crystal structure of (C6HF5S)6(DPPB)3-(C4H9O2NS)-(CH2Cl2) also verified the interaction between the oxygen atom of tetrahydrofuran and the fluorine in the pentafluorothiophenol ligand. The preparation of the above two single crystals laid the theoretical basis for subsequent fluorescence detection. The binding of the PtAg alloy nanoclusters prepared in this invention with homocysteine ​​occurs through oxygen-fluorine interaction near the 5F thiophenol ligand, thus verifying the growth of sulfolane containing two oxygen atoms or tetrahydrofuran containing one oxygen molecule, and finally Hcy containing an oxygen atom and a carboxyl group, in single crystals near the pentafluorothiophenol ligand; these single-crystal data laid the theoretical foundation for the fluorescence detection described later.

[0062] Pt1Ag prepared in Example 1 of this invention 14 The overall structure of the (C6F5S)6(DPPB)3 nanoclusters is as follows: Figure 1 and Figure 2 As shown.

[0063] Pt1Ag 14 The overall structure of (DPPB)3(C6F5S)6 is as follows: Figure 1 and 2 As shown: One platinum atom and 12 silver atoms together form an icosahedral metallic core. Then Pt1Ag 12 The metallic core is first covered by two Ag(C6F5S)3 studs to form a composite structure, and then surrounded by three DPPB ligands to form a monolithic structure. This is similar to the Pt1Ag structure reported in previous articles. 14 Unlike (SR)6(PPh3)8(H-SR:2-chloro-4-fluorobenzenethiol), Pt1Ag lacks a bisphosphine ligand on the Ag(C6F5S)3 short nail, which leads to the absence of a bisphosphine ligand. 12 The length of the silver-silver bonds between the kernel structure and the Ag(C6F5S)3 short spike motif has changed. (Pt1Ag) 14 Pt1Ag in (SR)6(PPh3)8 12 The average Ag-Ag bond distance between the metal core and the Ag(C6H3FClS)3(PPh3) short spike motif is approximately And Pt1Ag 14 (DPPB)3(C6F5S)6 metallic core Pt1Ag 12 The Ag-Ag bond distance between the short spike motif Ag(C6F5S)3 and the Ag-Ag bond is approximately This compositional structure promotes Ag-Ag metalophilic interactions within metal nanoclusters.

[0064] II. Pt1Ag 14 UV-Vis spectrum of (DPPB)3(C6F5S)6

[0065] The orange-yellow rhomboid Pt1Ag blocks prepared in Example 1 were used. 14 The UV spectrum of (DPPB)3(C6F5S)6 crystals dissolved in 2 mL of dichloromethane is shown below. Figure 3 As shown, the nanoclusters exhibit significant absorption peaks at 400 nm and 520 nm, followed by a weaker absorption peak at 460 nm.

[0066] III. Pt1Ag 14 Electrospray ionization mass spectrometry (ESI) analysis of (DPPB)3(C6F5S)6

[0067] Pt1Ag 14(DPPB)3(C6F5S)6 crystals were dissolved in a mixed solution of dichloromethane and methanol and analyzed by electrospray ionization mass spectrometry. In the ESI-MS spectrum, we found a 1-Da interval signal peak at m / z = 4201.9730 Da, attributed to [Pt1Ag]. 14 (C 28 H 28 The signal peak of P2)3(C6F5S)6Na]+, such as Figure 4 As shown. This experimental result confirms Pt1Ag 14 The (DPPB)3(C6F5S)6 metal nanoclusters are neutral. The accuracy of the structure was verified by combining crystal data and ESI-MS results.

[0068] IV. Pt1Ag 14 Investigation of the fluorescence properties of (DPPB)3(C6F5S)6

[0069] Due to Pt1Ag 14 (DPPB)3(C6F5S)6 crystals exhibit strong red fluorescence under ultraviolet light irradiation, therefore we investigated Pt1Ag... 14 (DPPB)3(C6F5S)6 photoluminescence properties, firstly Pt1Ag 14 (DPPB)3(C6F5S)6 exhibits red fluorescence under ultraviolet light. Pt1Ag 14 (DPPB)3(C6F5S)6 dissolved in dichloromethane solvent, excited at 400 nm, Pt1Ag 14 The emission peak of (DPPB)3(C6F5S)6 is located at 620 nm, such as Figure 5 As shown. Pt1Ag was obtained by excitation at 620 nm. 14 The excitation spectrum of (DPPB)3(C6F5S)6, with signal peaks at 523 nm, 402 nm, and 375 nm, is similar to the UV-Vis absorption spectrum of liquid metal nanoclusters. (PtAg) 14 The fluorescence lifetime of (DPPB)3(C6F5S)6 is 2.75 μs in CH2Cl2 solution and 3.44 μs in the solid state. Both liquid and solid states exhibit long lifetimes, with quantum yields (QY) of approximately 47.32% and 58.75%, respectively. Figure 6 and Figure 7 As shown, the remarkable fluorescence properties give the cluster the potential to effectively detect small molecules.

[0070] V. Pt1Ag 14 Application of (DPPB)3(C6F5S)6 in the Detection of Homocysteine

[0071] Pt1Ag14 An Investigation into the Optical Properties of Homocysteine ​​(Hcy) Detection Using Oxygen Injection from (DPPB)3(C6F5S)6 Figure 8 Pt1Ag prepared in Example 1 of this invention 14 The fluorescence response of (DPPB)3(C6F5S)6 to Hcy showed that as the Hcy concentration increased (from 0 μM to 400 μM), its fluorescence intensity increased by 1.3 times relative to the blank sample, indicating that Pt1Ag... 14 (DPPB)3(C6F5S)6 nanoclusters exhibit a good fluorescence response to Hcy.

[0072] Figure 9 Pt1Ag prepared in Example 1 of this invention 14 The graph shows the change in fluorescence intensity of (DPPB)3(C6F5S)6 after oxygen introduction. After oxygen introduction, the fluorescence intensity of the clusters significantly decreased, indicating that oxygen quenched the fluorescence. However, after oxygen introduction, the addition of Hcy (from 0 μM to 400 μM) gradually increased the fluorescence intensity again. Figure 10 As shown, its fluorescence intensity increased by 2 times after oxygen was introduced, 5F-Pt1Ag 14 The recognition effect of Hcy is significantly increased compared to that of oxygen-free oxygen. Figure 11 For the specific recognition of Hcy, Cys (cysteine) and Hcy (homocysteine) have very similar chemical structures and properties, making the specific detection of these two substances very challenging. Take 5F-Pt1Ag... 14 DCM stock solution (c=10) -3 mol / L), diluted to 10 with DCM -5 mol / L, to 5F-Pt1Ag 14 Add 300 μL (c = 10) to the DCM solution respectively -5 Cys (cysteine) and Hcy (homocysteine) were sampled at concentrations of mol / L and then fluorescence was measured. The fluorescence intensity identifying Hcy was 2.4 times that identifying Cys. (5F-Pt1Ag) 14 You can distinguish between Hcy and Cys. Figure 12 This indicates that under long-wavelength excitation, the 5F-Pt1Ag... 14 The intensity of the three-photon fluorescence gradually decreased. Figure 13 This indicates that as the Hcy concentration increases (from 0 μM to 300 μM), 5F-Pt1Ag... 14 The three-photon fluorescence intensity gradually increased, and the fluorescence intensity after recognition was 1.4 times that before recognition. After interacting with Hcy, 5F-Pt1Ag 14 The three-photon absorption cross section is 3.71 × 10⁻⁶. -82 cm 6s 2 photon -2 It is 1.3 times that before recognition. Figure 14 ). Figure 15 This indicates that after introducing oxygen, the addition of Hcy (concentration from 0 μM to 300 μM) increased the fluorescence intensity by 9.6 times, and the three-photon absorption cross-section reached as high as 35.5 × 10⁻⁶. -82 cm 6 s 2 photon -2 ( Figure 16 ), is 5F-Pt1Ag 14 9.3 times that of 5F-Pt1Ag, thus demonstrating that 5F-Pt1Ag is more potent in the presence of oxygen. 14 It exhibits better Hcy recognition capability under long-wavelength excitation and higher contrast compared to single-photon fluorescence.

[0073] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A PtAg alloy nanocluster, characterized in that, Its general molecular formula is Pt1Ag 14 (DPPB)3(C6F5S)6, wherein DPPB is bis(diphenylphosphine)butane and C6F5S is pentafluorothiophenol; the PtAg alloy nanoclusters consist of an icosahedral metal core composed of one platinum atom and 12 silver atoms, Pt1Ag 12 The metallic core is first covered by two Ag(C6F5S)3 pins to form a composite structure, and then surrounded by three DPPB ligands.

2. A method for preparing PtAg alloy nanoclusters according to claim 1, characterized in that, Includes the following steps: Tetraoctylammonium bromide was dissolved in a mixed solution of dichloromethane and methanol. A silver source aqueous solution was added and stirred. A platinum source aqueous solution was added and stirred. Then, 2,3,4,5,6-pentafluorothiophenol and 1,4-bisdiphenylbutane were added sequentially to carry out the initial reaction to obtain a mixed solution. A methanol solution of tert-butylamine borane was added to the mixed solution to carry out a one-pot reduction reaction to obtain a crude product. After crystallization, PtAg alloy nanoclusters were obtained.

3. The preparation method according to claim 2, characterized in that, The ratio of tetraoctylammonium bromide, silver source, platinum source, 2,3,4,5,6-pentafluorothiophenol, 1,4-bis(diphenylbutane) and tert-butylamine borane is 2 mg:4.59 µmol:0.49 µmol:1 µL:1 mg:4 mg.

4. The preparation method according to claim 2, characterized in that, The silver source is silver nitrate.

5. The preparation method according to claim 2, characterized in that, The platinum source is chloroplatinic acid.

6. The preparation method according to claim 2, characterized in that, The one-pot reduction reaction takes 10-12 hours.

7. The preparation method according to claim 2, characterized in that, The initial reaction time is 15-30 minutes.

8. The preparation method according to claim 2, characterized in that, Before crystallization, the crude product was dissolved in dichloromethane, mixed with ethanol and shaken until homogeneous, ultrasonically cleaned, centrifuged, and the precipitate was collected. The precipitate was dissolved in dichloromethane and coated onto a TLC silica gel plate for purification.

9. The application of the PtAg alloy nanoclusters according to claim 1 in the detection of homocysteine.

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