Dinuclear copper cluster with pressing luminescence color-changing effect and preparation method thereof

Abstract

The invention belongs to the technical field of precise chemical synthesis of cluster molecules, and particularly relates to a preparation method of a binuclear copper cluster (Cu2 cluster) which can be simply, conveniently and quickly prepared in a macroscopic quantity and has a precise atomic structure and a pressing luminescent color-changing effect and an obtained product. The binuclear copper cluster provided by the invention comprises two Cu atoms and three diphenyl-2-pyridine phosphorus ligands. The center is formed by two triangles sharing one bottom, each copper is coordinated with a P atom of one diphenyl-2-pyridylphosphine ligand, and a P atom and an N atom of the other diphenyl-2-pyridylphosphine ligand are respectively coordinated with two copper. Compared with a reported luminescent Cu cluster synthesis method, the synthetic method disclosed by the invention has the advantages of simplicity, convenience, quickness, high yield, easiness in crystallization, high universality and the like; and the Cu2 cluster obtained based on the method has a reversible pressing luminescent discoloration phenomenon.

Description

Technical Field

[0001] The present invention belongs to the technical field of precise chemical synthesis of cluster molecules. Specifically, it relates to a binuclear copper cluster (Cu2 cluster) with precise atomic structure and suppressed luminescence and color-changing effect, which can be prepared simply, quickly and in large quantities, and a preparation method thereof. Background Art

[0002] In recent years, metal clusters have attracted considerable attention from researchers due to their unique physicochemical properties. Among these properties, suppressed luminescence color change is one of their most important characteristics. Research results have shown that this suppressed luminescence color change exhibits the following characteristics: reversibility, pressure sensitivity, environmental stability, low toxicity, and controllability. These properties make luminescent metal clusters promising for applications in sensors, data storage, optical devices, security identification, and other fields. Therefore, the development of simple, convenient, and universal methods for the mass production of metal clusters with high quantum yields has become a hot topic among cluster scientists.

[0003] Currently, luminescent metal clusters are primarily gold clusters, which are relatively expensive and thus unsuitable for large-scale application. In contrast, copper clusters possess luminescent properties comparable to those of gold clusters, while also offering advantages such as abundant raw material reserves and low cost. These clusters offer unique advantages in developing inexpensive, high-performance luminescent materials and hold significant research value. Therefore, developing simple, rapid, and large-scale methods for the preparation of precisely structured luminescent Cu clusters, as well as finding universal synthesis methods, is crucial. Summary of the Invention

[0004] The present invention provides a method for preparing atomically precise, compressible, color-changing, and luminescent binuclear copper clusters that can be synthesized simply, quickly, and in large quantities. Compared with previously reported methods for synthesizing luminescent Cu clusters, the method is simpler, more universal, has a higher yield, and is easier to crystallize.

[0005] The present invention also provides a method for preparing the atomic structure precise luminescent Cu2 cluster obtained by the above preparation method, and the Cu2 cluster exhibits good photoluminescence performance in air.

[0006] The technical solutions adopted by the present invention to achieve the above-mentioned purpose are as follows: The present invention provides a method for preparing a Cu2 cluster having a suppressed luminescence and color-changing effect, comprising the following steps: (1) Dissolve cuprous iodide in acetonitrile solution and dissolve diphenyl-2-pyridinium phosphine in acetonitrile solution; (2) Mix the two solutions and shake them evenly. After filtering, the mother liquor is crystallized to obtain Cu2 clusters.

[0007] Preferably, in step (1), the concentration of cuprous iodide in acetonitrile is 0.03-0.04 mol / L; the concentration of diphenyl-2-pyridinium phosphine in acetonitrile is 0.03-0.04 mol / L.

[0008] Preferably, in step (1), the molar ratio of cuprous iodide to diphenyl-2-pyridinium phosphine is 1:1.

[0009] Preferably, in step (2), the crystallization time is 30-60 min.

[0010] Preferably, the preparation process is carried out in an ice bath.

[0011] The present invention also provides a Cu2 cluster with a suppressed luminescence color-changing effect prepared using the above-mentioned preparation method. The Cu2 cluster is a single-ligand protected binuclear cluster containing 2 Cu atoms and 3 diphenyl-2-pyridinium phosphites. The precise structure of the Cu2 cluster consists of two triangles composed of Cu2I2 and 3 diphenyl-2-pyridinium phosphites.

[0012] Preferably, the molecular formula of the Cu2 cluster is Cu2I2(C 51 H 44 N3P3).

[0013] Preferably, the Cu2 cluster belongs to the triclinic system with space group P-1, a=13.5675(6), b= 13.8593(5), c=15.6406(6), α=103.2480(10)°, β=102.2150(10)°, γ=117.5170(10)°.

[0014] The present invention provides a universal method for preparing a diphenyl-2-pyridinium phosphine ligand-protected binuclear copper cluster. The binuclear copper cluster prepared by the present invention is a single-ligand-protected binuclear cluster containing two Cu atoms and three diphenyl-2-pyridinium phosphine atoms. The precise structure of the Cu2 is composed of two triangles composed of Cu2I2 and three diphenyl-2-pyridinium phosphine atoms.

[0015] Compared with the existing synthesis method, the method mentioned in the present invention has the following advantages: (1) In the existing methods for preparing metal clusters, a reducing agent such as NaBH4 is usually required to react. However, this preparation method does not require the addition of a reducing agent, and has fewer reaction steps, and the reaction can be completed in about half an hour.

[0016] (2) The preparation method provided by the present invention can be used to synthesize and press luminescent and color-changing Cu2 clusters in batches. The Cu2 clusters obtained by this method are easy to crystallize, and the conditions required for crystallization are simple and the time is short.

[0017] (3) The Cu2 clusters prepared by this method exhibit good suppressed luminescence and color change phenomenon under certain pressure conditions, and are expected to be applied in practical fields such as sensors, data storage, optical devices, and security signs. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the structure of Cu2 cluster; Figure 2 It is the suppressed luminescence color change phenomenon of Cu2; Figure 3 The pressure-induced color emission spectrum (a) and pressure-release emission spectrum (b) of the Cu2 cluster are shown; Figure 4 is the UV-visible absorption spectrum of Cu2 cluster. DETAILED DESCRIPTION

[0019] The present invention will be further described below with reference to specific examples.

[0020] The three Cu2 clusters provided by the present invention have the following molecular formula: The molecular formula of Cu2 cluster is Cu2I2(C 51 H 44 N3P3), the Cu2 cluster belongs to the triclinic system with space group P-1, a=13.5675(6), b=13.8593(5), c=15.6406(6), α=103.2480(10)°, β=102.2150(10)°, γ=117.5170(10)°.

[0021] The present invention provides a universal method for quickly and easily synthesizing luminescent Cu clusters with precise structures in large quantities. The specific preparation method of the binuclear copper clusters at room temperature is as follows: (1) Dissolve cuprous iodide in acetonitrile solution and dissolve diphenyl-2-pyridinium phosphine in acetonitrile solution. (The molar ratio of cuprous iodide to diphenyl-2-pyridinium phosphine is 1:1) (2) Mix the two solutions and shake them evenly to obtain a yellow-green transparent solution.

[0022] (3) Use a filter membrane to filter the small amount of yellow-green precipitate produced in the solution.

[0023] (4) The filtered yellow-green clear and transparent mother liquor is sealed with a sealing film, and then directly diffused after being pierced with a needle. Yellow-green crystals are precipitated in 30-60 minutes. The crystals emit yellow-green light under ultraviolet light (365 nm).

[0024] Example 1: Synthesis of Cu2 Clusters The entire preparation process was carried out in an ice bath.

[0025] First, add 38 mg of CuI and 6 ml of acetonitrile to a 10 ml centrifuge tube. Add 52.6 mg of diphenyl-2-pyridinium phosphine to another 10 ml centrifuge tube and shake to fully dissolve them in the acetonitrile. Pour the solutions from both centrifuge tubes into a 20 ml vial and shake to thoroughly mix the two solutions, resulting in a yellow-green transparent mixed solution. Filter the small amount of yellow-green precipitate from the solution using a 5 ml syringe fitted with an organic filter, resulting in a clear, yellow-green mixed solution. Seal the filtered mixed solution with parafilm, pierce the vial with a needle, and allow it to diffuse directly. Yellow-green crystals will begin to precipitate after approximately 30 minutes. The crystals emit a yellow-green luminescence under ultraviolet light (365 nm).

[0026] Effect embodiment The Cu2 cluster prepared in Example 1 was further characterized as follows: Under an optical microscope, the crystals were selected and a good quality crystal was selected for testing under nitrogen atmosphere (170 K). The data was then integrated and reduced using APEX 3 software. The structure was then solved and improved using ShelXT and ShelXL programs in Olex2 software. All Cu, P, and N atoms were found directly, and the remaining non-hydrogen atoms were generated by differential Fourier synthesis. All non-hydrogen atoms were anisotropically refined. All hydrogen atoms were positioned by geometric calculations and isotropically refined. The SQUEEZE method in PLATON was used to remove the electron density generated by residual solvent molecules from the data, and the resulting data were further refined. Detailed crystal data for Cu2 are shown in the table below.

[0027] Table 1 The structure of the Cu2 cluster was obtained by X-ray single crystal diffraction analysis. The results showed that Cu2 is a single ligand protected Cu cluster containing two Cu atoms and three diphenyl-2-pyridinium phosphonium atoms. The precise structure of Cu2 consists of two triangles composed of Cu2I2 and three diphenyl-2-pyridinium phosphonium atoms, as shown in Figure 2. Figure 1 Therefore, the Cu2 cluster is specifically Cu2, and its molecular formula is Cu2I2(C 51 H 44 N3P3).

[0028] The pressure test results of Cu2 are as follows Figure 2As shown, when the pressure is 1 atm, the crystal emits green light. When the atmospheric pressure increases to 4.0 GPa, it begins to turn into orange-yellow light. When it reaches 5.0 GPa, the crystal completely turns into orange light. As the pressure increases, the intensity of the orange light becomes smaller and smaller. When the pressure increases to 12 GPa, the crystal stops emitting light. At this time, the pressure begins to be released. When the pressure is released to 7.0 GPa, the crystal begins to emit yellow-green light again. When the pressure is released to 5.0 GPa, the crystal begins to emit faint green light. As the pressure decreases, the intensity of the green light becomes stronger and stronger until the pressure is completely released.

[0029] The pressure luminescence spectrum of Cu2 is as follows Figure 3 As shown in (a), as the pressure increases, the position of the emission peak red-shifts and the emission intensity becomes smaller and smaller.

[0030] The decompression light emission spectrum of Cu2 is as follows Figure 3 As shown in Figure b, as the pressure increases, the position of the emission peak blue-shifts and the emission intensity becomes larger and larger. When the pressure is completely released, the position and intensity of the emission peak return to their original state.

[0031] The UV spectrum of Cu2 is as follows Figure 4 As shown, two shoulder peaks appeared at 311 nm and 265 nm.

Claims

1. A method for preparing a Cu2 cluster with a suppressed luminescence and color change effect, characterized in that: The steps include: (1) Dissolve cuprous iodide in acetonitrile solution and dissolve diphenyl-2-pyridinium phosphine in acetonitrile solution; (2) Mix the two solutions and shake them evenly. After filtering, the mother liquor is crystallized to obtain Cu2 clusters.

2. The preparation method according to claim 1, characterized in that In step (1), the concentration of cuprous iodide in acetonitrile is 0.03-0.04 mol / L; the concentration of diphenyl-2-pyridinium phosphine in acetonitrile is 0.03-0.04 mol / L.

3. The preparation method according to claim 1 or 2, characterized in that In step (1), the molar ratio of cuprous iodide to diphenyl-2-pyridinium phosphine is 1:

1.

4. The preparation method according to any one of claims 1 to 3, characterized in that In step (2), the crystallization time is 30-60 min.

5. The preparation method according to any one of claims 1 to 4, characterized in that The preparation process was carried out in an ice bath.

6. A Cu2 cluster having a pressed luminescence color change effect prepared by the preparation method according to any one of claims 1 to 5, characterized in that: The Cu2 cluster is a single-ligand protected binuclear cluster containing two Cu atoms and three diphenyl-2-pyridinium phosphonates; the precise structure of the Cu2 cluster consists of two triangles composed of Cu2I2 and three diphenyl-2-pyridinium phosphonates.

7. The atomically precise, suppressible, luminescent and color-changing Cu2 cluster according to claim 6, characterized in that: The molecular formula of the Cu2 cluster is Cu2I2(C 51 H 44 N3P3).

8. The atomically precise, suppressible, luminescent and color-changing Cu2 cluster according to claim 7, characterized in that: The Cu2 cluster belongs to the triclinic system with space group P-1, a=13.5675(6), b= 13.8593(5), c=15.6406(6), α=103.2480(10)°, β=102.2150(10)°, γ=117.5170(10)°.

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