Near-infrared luminous gold-copper doped nano-cluster material as well as synthesis method and application thereof

Abstract

The invention discloses a near-infrared luminous gold-copper doped nano-cluster material as well as a synthesis method and application thereof, and belongs to the crossing field of coordination chemistry and nano materials. Thioether gold and copper hexafluorophosphate tetraacetonitrile serve as raw materials, binaphthyl dithiophosphate (R / S-PS) is used for coordination protection, a reducing agent diphenyl silane (Ph2SiH2) is added, the gold-copper-doped nano-cluster material with the near-infrared light emitting function is obtained through a one-pot reduction method, the molecular formula of an enantiomer cluster is Au13Cu4 (C20H12O2PS2) 12 (C7H17NCl) 3, the abbreviation is R / S-Au13Cu4, the enantiomer cluster belongs to an orthorhombic system, and the molecular formula of the enantiomer cluster is shown in the description. And the space group is a chiral space group C222. The material shows a remarkable aggregation-induced emission (AIE) characteristic in a dichloromethane / cyclohexane system. The compound shows strong near-infrared emission at 725 nm in an aggregation state, the photoluminescence quantum yield is as high as 35%, and the compound has a remarkable two-photon excitation luminescence characteristic. The excellent optical properties lay a foundation for realizing high-quality cell imaging application under 740 nm exciting light.

Description

Technical Field

[0001] This invention belongs to the interdisciplinary field of coordination chemistry and nanomaterials, specifically relating to a near-infrared luminescent gold-copper doped nanocluster material, its synthesis method, and its application in two-photon excited cell imaging. Background Technology

[0002] Near-infrared luminescent materials have wide applications in many fields. They have significant advantages over traditional fluorescent probes in the field of bioimaging. Their two-photon excitation luminescence properties can optimize imaging performance. However, existing near-infrared materials such as organic dyes and quantum dots still face many challenges.

[0003] Metal nanoclusters have become an ideal platform for developing next-generation near-infrared (NIR) fluorescent probes due to their atomically precise structure, tunable and stable luminescence properties, long phosphorescence lifetime, and good biocompatibility. Many gold nanoclusters containing zero-valent gold atoms typically exhibit near-infrared luminescence properties, but their photoluminescence quantum yield (PLQY) is usually low (<10%), especially in solution, at room temperature.

[0004] Doping with dissimilar metal atoms has proven to be an effective way to modulate the physicochemical properties of nanoclusters. Doping with copper atoms not only enhances the stability of gold nanoclusters but also significantly improves their photoluminescence properties. This is because the introduction of copper atoms enhances structural rigidity, suppresses nonradiative decay, and promotes intersystem crossing, thereby greatly improving the luminescence performance of the nanoclusters. Therefore, studying gold-copper doped nanoclusters and developing them into near-infrared fluorescent probes has potential application value in two-photon excited cell imaging. Summary of the Invention

[0005] The purpose of this invention is to synthesize a near-infrared luminescent gold-copper doped nanocluster material with good luminescence properties; another purpose is to provide its application in two-photon excited cell imaging.

[0006] To achieve the objectives of this invention, a near-infrared luminescent gold-copper doped nanocluster material was synthesized, with the chemical formula: C 240 H 144 Au 13 Cu4O 24 P 12 S 24 (abbreviated as: R / S -Au 13 Cu4), belongs to the orthorhombic crystal system, and its space group is chiral space group. C222, where, S-Au13Cu4: α = β = γ = 90°, a = 25.6136(5) Å, b=36.2673(10) Å, c =19.3966(4) Å, V = 18018.2(7)Å 3 ;R-Au13Cu4: α = β = γ = 90°, a =25.7272(12)Å, b=35.8502(16) Å, c = 19.4577(7) Å, V = 17946.3(13)Å 3 The ligands are R / S -Binaphthyl dithiophosphate ( Figure 1 As shown, abbreviated as R / S -PS).

[0007] The method for preparing the gold-copper doped nanocluster material of the present invention is achieved through the following steps: sulfide gold and S -PS ligands or R -PS was dissolved in dichloromethane solution. While stirring, a copper hexafluorophosphate tetraacetonitrile solution in acetone was added, followed by triethylamine. The solution color changed from yellow to colorless. Diphenylsilane was then added under vigorous stirring, and the reaction was carried out in the dark. After the reaction was complete, the mixture was centrifuged. Dichloromethane and acetonitrile were added to the supernatant, and the mixture was allowed to evaporate slowly at room temperature in the dark to obtain gold-copper doped nanoclusters. These materials were then washed and dried.

[0008] The gold-copper doped nanoclusters exhibit a double core-shell structure: the core is a classic Au core. 13 The structure is icosahedral, surrounded by a Cu4 tetrahedral shell, with the outermost layer consisting of 12... S -PS ligand protection. Structural analysis revealed R / S - The unique coordination mode of the PS ligand: one S atom coordinates with the Cu atom in the Cu4 shell, while the other S atom coordinates with Au. 13 Au atoms in the core form coordinate bonds ( Figure 2 (As shown).

[0009] The properties of the near-infrared luminescent gold-copper doped nanoclusters of this invention, applied to two-photon excited cell imaging, are described in detail below: The material has a stable crystalline structure. Figure 3 As shown). Under air at room temperature, the material exhibits significant aggregation-induced emission characteristics in a dicyclohexane / dichloromethane mixed solution, with the strongest emission occurring at 70%. At an excitation wavelength of 370 nm, it shows strong broadband emission near 725 nm, with a full width at half maximum (FWHM) of 120 nm and a quantum yield of 35%.Figure 4 The emission lifetime is 1.81 μs (as shown in the figure); Figure 5 The two-photon emission spectrum of the material in a cyclohexane / dichloromethane mixed solution with different proportions is consistent with the trend of single-photon AIE (excitation wavelength: 800 nm, excitation power: 200 mW) (as shown in the figure); Figure 6 The two-photon excitation luminescence spectrum of the material in a cyclohexane / dichloromethane solution with a volume ratio of 70% under different powers gradually increases with the increase of power (excitation wavelength: 800 nm (as shown in the figure); Figure 7 The two-photon luminescence intensity of the material is proportional to the square of the power (as shown in the figure); Figure 8 The slope of the relationship between the two-photon luminescence intensity of the material and the power is 1.94 (as shown in the figure); Figure 9 After the material is incubated with HCC827 cells, confocal imaging under different excitation lights is performed, and the cells show red luminescence under 740 nm excitation (as shown in the figure). Figure 10

[0010] The gold and copper doped nanocluster material has excellent near-infrared luminescence characteristics, and has strong broadband emission at 725 nm in an aggregated state, and the photoluminescence quantum yield is as high as 35%. In the aggregated state, the cluster can realize two-photon excitation luminescence under 800 nm excitation, and can realize lung cancer cell imaging under 740 nm excitation. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 It is a protection ligand structure of the gold and copper doped nanocluster material.

[0012] Figure 2 It is a pair of enantiomer structure diagram of the gold and copper doped nanocluster material.

[0013] Figure 3 It is a PXRD diagram of the gold and copper doped nanocluster material.

[0014] Figure 4 It is an excitation curve and an aggregation induced emission curve diagram of the gold and copper doped nanocluster material.

[0015] Figure 5 It is a luminescence lifetime curve diagram of the gold and copper doped nanocluster material.

[0016] Figure 6 It is a two-photon excitation luminescence spectrum of the gold and copper doped nanocluster material in a cyclohexane / dichloromethane solution.

[0017] Figure 7 It is a two-photon excitation luminescence spectrum of the gold and copper doped nanocluster material under different powers. ​

[0018] Figure 8 The relationship between the two-photon luminescence intensity and the square of power of the gold copper doped nanocluster material of the application.

[0019] Figure 9 The graph slope curve of the relationship between the luminescence intensity and the power of the gold copper doped nanocluster material of the application.

[0020] Figure 10 The confocal imaging of the gold copper doped nanocluster material of the application and HCC827 cells under different excitation light. DETAILED DESCRIPTION

[0021] The application will be further described below by examples: Example 1: Synthesis of the gold copper doped nanocluster material of the application Me2SAuCl (5 mg, 0.017 mmol) and S -PS or R -PS ligand (10 mg, 0.026 mmol) was dissolved in 2 mL DCM solution, under stirring condition, Cu(CH3CN)4PF6 (2 mg, 0.006 mmol) acetone solution (1 mL) was added, then 50 μL triethylamine was added, the solution color changed from yellow to colorless, then 10 μL of Ph2SiH2 was added under vigorous stirring, the reaction solution was stirred in dark condition for 24 h, the above reaction mother liquor was centrifuged. The supernatant was added with 2 mL DCM, 1 mL acetonitrile, and slowly evaporated at room temperature in dark condition. After about 4-6 days, red block crystals S -Au 13 Cu4 precipitated, the red block crystals were collected by filtration, the yield was 9% (based on Au), washed with acetone, and dried at room temperature for testing and characterization.

[0022] The gold copper doped nanocluster material of the application prepared in Example 1 was taken for further characterization, and the process was as follows: (1) Crystal structure determination The X-ray single crystal diffraction data of the complex was obtained by using a single crystal sample with appropriate size on a Rigaku XtaLAB Synergy Custom single crystal diffractometer, Cu-K α radiation ( LambdaThe diffraction patterns were determined at 200 K using CuKα rays (λ = 1.54184 Å) monochromated with graphite as the diffraction source via ω-scanning, and corrected for Lp factor and semi-empirical absorption. Structural analysis was performed by first obtaining the initial structure using the direct method with the SHELXL-97 program, followed by refinement using the full-matrix least squares method with the SHELXL-97 program. All non-hydrogen atoms were refined using anisotropic thermal parameters. All hydrogen atoms were refined using isotropic thermal parameters. Detailed crystallographic data are shown in Table 1; important bond length data are shown in Table 2.

[0023] Table 1. Main crystallographic data of the gold-copper doped nanocluster material of the present invention. Table 1. Main crystallographic data Table 2 S -Au 13 Important bond lengths (Å) in Cu4 Atom-Atom Bond length (A) Atom-Atom Bond length (A) Au1-Au2 2.7503(14) Au4 - Au2 1 ]]> 2.830(3) Au1-Au2 1 ]]> 2.7503(14) Au4 - Au3 3 ]]> 2.810(3) Au1-Au2 2 ]]> 2.7503(14) Au4 - Au4 1 ]]> 3.032(4) Au1-Au2 3 ]]> 2.7503(14) Au4-Cu1 2.876(7) Au1-Au3 2.7718(16) Au5-Au5 2 ]]> 2.991(12) Au1 - Au3 1 ]]> 2.7719(16) Au5-Au6 2.828(11) Au1-Au3 3 ]]> 2.7719(16) Au5-Au6 2 ]]> 2.952(12) Au1-Au3 2 ]]> 2.7719(16) Au5-Au7 3 ]]> 2.941(11) Au1-Au4 3 ]]> 2.7745(15) Au5-Au7 2.864(11) Au1-Au4 2.7746(15) Au 5 - Cu 1 3 ]]> 2.956 (11) Au1-Au4 1 ]]> 2.7745(15) Au6 - Au5 2 ]] 2.952(12) Au1-Au4 2 ]]> 2.7745(15) Au6-Au6 1 ]]> 3.066(11) Au2-Au2 2 ]]> 2.994(3) Au6-Au7 1 ]]> 2.983(13) Au2 - Au3 2 ]] 2.836(3) Au6-Au7 2.830 (13) Au2-Au3 2.947(3) Au 6 - Cu 1 1 ]] 2.944(14) Au2 - Au4 1 ]]> 2.830(3) Au7 - Au5 3 ]]> 2.941(11) Au2-Au4 2.934(3) Au7 - Au6 1 ]]> 2.983(13) Au2-Cu1 1 ]]> 2.868(8) Au7-Au7 3 ]]> 3.020(10) Au3-Au2 2 ]]> 2.836(3) Au7-Cu1 2.968(11) Au3-Au3 3 ]]> 2.986(3) Cu1-Au2 1 ]]> 2.868(8) Au3-Au4 2.952(3) Cu1-Au3 3 ]]> 2.897(6) Au3-Au4 3 ]]> 2.810(3) Cu1-Au5 3 ]]> 2.956(11) Au3-Cu1 3 ]]> 2.897(6) Cu1-Au6 1 ]]> 2.944(14) Symmetry codes: 1 +X, -1-Y, -2-Z; 2 -1-X, -1-Y,+Z; 3 -1-X, +Y, -2-Z; 4 -3 / 2-X, -1 / 2-Y, +Z; 5 -2-X, -1-Y,+Z Example 2: Application of the gold-copper doped nanoclusters of the present invention in two-photon excited cell imaging.

[0024] The gold-copper doped nanoclusters prepared in Example 1 ( S -Au 13 After further processing of the Cu4 sample, it was cultured with HCC827 cells under standard culture conditions. RPMI-1640 medium containing 10% fetal bovine serum (FBS) and antibiotics (penicillin 100 U / mL and streptomycin 100 μg / mL) was used as the growth substrate. The cells were placed in an incubator at 37°C with 5% CO2 and appropriate humidity to maintain normal growth and proliferation.

[0025] Depend on Figure 10 It is known that, after incubating the gold-copper doped nanoclusters of the present invention with HCC827 cells, confocal imaging under different excitation lights showed that, under 740 nm excitation, the cells exhibited red luminescence.

[0026] The above examples are only used to illustrate the content of the present application, and the present application has other embodiments in addition thereto. However, any technical solution formed by equivalent replacement or equivalent transformation falls within the protection scope of the present application.

Claims

1. A chiral nanogold copper-doped nanocluster material, characterized in that: The chemical formula is: C 240 H 144 Au 13 Cu4O 24 P 12 S 24 , and the abbreviation is: R / S -Au 13 Cu4, belongs to the orthorhombic system, and the space group is chiral space group C 222, wherein, S -Au 13 Cu4: α = β = γ = 90°, a = 25.6136(5) Å, b=36.2673(10) Å, c =19.3966(4) Å, V = 18018.2(7)Å 3 ; R -Au 13 Cu4: α = β = γ = 90°, a =25.7272(12)Å, b= 35.8502(16) Å, c = 19.4577(7)Å, V = 17946.3(13)Å 3 ; the ligand is R / S -PS, which is R / S -bisnaphthalene dithiophosphate, and the molecular structural formula is as follows:

2. The chiral nanogold copper-doped cluster material of claim 1, wherein: with a double-layer core-shell structure, the inner core is Au 13 octahedral structure, surrounded by a Cu4 tetrahedral shell layer, and protected by 12 PS ligands on the outermost layer; one S atom in the ligand coordinates with the Cu atom of the Cu4 shell layer, and the other S atom coordinates with the Au 13 The Au atoms of the inner core form coordination bonds.

3. A method of preparing the chiral nanogold copper-doped nanocluster material of claim 1 or 2, characterized by: The thioether gold and S -PS ligand or R -PS is dissolved in dichloromethane solution, stirring in the tetraacetonitrile copper hexafluorophosphate acetone solution, then adding triethylamine, then adding diphenylsilane, stirring in the dark, after the reaction is completed, centrifugation; In the supernatant, dichloromethane and acetonitrile are added, slowly evaporated at room temperature in the dark, and the gold copper doped nanocluster material is obtained, which is washed, dried and ready for use.

4. Use of the chiral nanogold copper-doped nanocluster material according to claim 1 or 2 in two-photon excited cellular imaging, characterized in that: Samples containing the material were co-incubated with imaged cells, followed by confocal imaging under 740 nm excitation light.

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