An octahedral Pd6(SR)12 cluster and its preparation method

Abstract

The application provides a Pd6(SR) 12 cluster with an octahedral structure, the Pd6(SR) 12 cluster is a cyclohexanethiol ligand-protected palladium cluster, contains 6 Pd atoms, 12 cyclohexanethiol ligands, the 6 Pd atoms form an octahedral core, and the sulfur atoms in the cyclohexanethiol ligands are connected with the Pd atoms peripherally, and each sulfur atom is connected with two Pd atoms. The application further discloses a preparation method of the Pd6(SR) 12 cluster, and the application fills the technical vacancy of synthesizing Pd clusters with structures other than a ring structure, and has high popularization value.

Description

Technical Field

[0001] This invention relates to the field of nanomaterial preparation technology, and more specifically, to an octahedral Pd6(SR) structure. 12 Clusters and their preparation methods. Background Technology

[0002] Metal nanoclusters are aggregates of several to hundreds of metal atoms, typically smaller than 3 nm, and represent an emerging type of nanomaterial. They possess discrete electronic energy levels, exhibiting unique optical, electrical, and catalytic physicochemical properties. Ligand-protected metal nanoclusters show broad application prospects in various fields, including biolabeling, catalysis, medicine, photovoltaics, sensing, and renewable energy. Furthermore, the physicochemical properties of nanoclusters are closely related to their structure and size, giving them enormous application potential in certain areas.

[0003] Ligand-protected metal nanoclusters have always been a research hotspot. Currently, common ligand-protected metal nanoclusters include core-shell group IB clusters and cyclic group VIII metal clusters. Among cyclic clusters, palladium has been studied relatively little. Palladium metal clusters have good antioxidant, anti-reduction, and thermal stability, as well as excellent electrocatalytic and nonlinear optical properties.

[0004] A series of cyclic palladium clusters [Pd(SR)2] have been reported to date. n (n = 4 to 20), but so far, no Pd clusters with structures other than cyclic structures have been synthesized, and similarly, no related preparation methods have been reported. Summary of the Invention

[0005] One of the technical problems to be solved by the present invention is to provide an octahedral Pd6(SR) structure. 12 The cluster was identified, and its structure differed from previously reported ring structures. The precise structure was obtained by X-ray single-crystal diffraction.

[0006] To address the aforementioned problems, this invention provides an octahedral Pd6(SR) structure. 12 Clusters, namely Pd6(SR) 12 The cluster is a palladium cluster protected by cyclohexylthiol ligands, containing 6 Pd atoms and 12 cyclohexylthiol ligands. The 6 Pd atoms form an octahedral core, and the sulfur atoms in the cyclohexylthiol ligands are connected to the Pd atoms on the periphery, with each sulfur atom connecting to two Pd atoms.

[0007] As a preferred embodiment, the Pd6(SR) 12 The molecular formula of the cluster is Pd6(SC6H) 11 ) 12 It belongs to the triclinic crystal system and has the space group P-1.

[0008] As a preferred embodiment, the Pd6(SR) 12 The crystallographic parameters of the cluster are: α=91.025(5), β=107.110(5), γ=104.164(5).

[0009] The second objective of this invention is to provide an octahedral Pd6(SR) structure. 12 A method for preparing clusters is proposed, thereby solving the problem that the aforementioned octahedral structure of Pd6(SR) is currently unavailable. 12 Problems with cluster preparation methods.

[0010] To address the aforementioned problems, the present invention provides a Pd6(SR) structure with an octahedral shape. 12 The method for preparing clusters includes the following steps:

[0011] S1: Dissolve palladium salt in acetonitrile and stir for a period of time to obtain a brown solution A containing palladium ions.

[0012] S2: Add cyclohexanethiol to the brown solution A from step S1, and continue stirring the reaction for a period of time to obtain a yellow-brown solution B.

[0013] S3: Add the yellow-brown solution B from step S2 to triethylamine, stir the reaction, centrifuge the product to precipitate, and wash repeatedly to remove excess thiol to obtain yellow precipitate C.

[0014] S4: Dissolve the yellow precipitate C obtained in step S3 in an organic solvent, extract to obtain a red solution, separate by thin-layer chromatography, extract the separated product with an organic solvent, and culture it into single crystals to obtain Pd6(SR) with an octahedral structure. 12 Cluster.

[0015] As a preferred embodiment, in step S1, the palladium salt is palladium acetate trimer.

[0016] As a preferred embodiment, in step S1, the stirring rate is 600-1000 r / min, and the stirring reaction time is 15-20 min.

[0017] As a preferred embodiment, in step S2, the molar ratio of cyclohexylthiol to palladium ions is (1-12):1.

[0018] As a preferred embodiment, in step S2, the stirring rate of the stirring reaction is 600-1000 r / min, and the stirring reaction time is 15-20 min.

[0019] As a preferred embodiment, in step S3, the molar ratio of triethylamine to palladium ions is (1-8):1.

[0020] As a preferred embodiment, in step S3, the stirring rate is 600-1000 r / min, and the stirring reaction time is 6-10 h.

[0021] As a preferred embodiment, in step S3, acetonitrile is used for centrifugal washing 1 to 5 times at a centrifugation speed of 10,000 rpm / min.

[0022] As a preferred embodiment, in step S4, the organic solvents are dichloromethane and / or toluene, respectively.

[0023] Compared with existing cyclic Pd clusters, the present invention has the following advantages:

[0024] (1) Compared with previously reported cyclic Pd6 clusters, this Pd6(SR) 12 Clusters have a unique octahedral structure.

[0025] (2) Pd6(SR) with octahedral structure 12 The UV-vis absorption spectrum of the clusters is significantly different from that of previously reported cyclic Pd6 clusters, demonstrating that the core structure has a great influence on the optical properties and electronic structure of nanoclusters, which is of great significance for studying the influence of structural isomers on optical properties.

[0026] (3) Palladium clusters have good electrocatalytic performance and can catalyze the direct synthesis of hydrogen peroxide from hydrogen and oxygen. The octahedral Pd6(SR) 12 The study of clusters helps to deepen our understanding of the relationship between structure and properties. Attached Figure Description

[0027] Figure 1 Pd6(SR) has an octahedral structure. 12 Crystal structure diagram Detailed Implementation

[0028] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] This invention provides an octahedral Pd6(SR) structure. 12 Clusters, namely Pd6(SR) 12The cluster is a palladium cluster protected by cyclohexylthiol ligands, containing 6 Pd atoms and 12 cyclohexylthiol ligands. The 6 Pd atoms form an octahedral core, and the sulfur atoms in the cyclohexylthiol ligands are connected to the Pd atoms on the periphery, with each sulfur atom connecting to two Pd atoms.

[0030] Preferably, the Pd6(SR) 12 The molecular formula of the cluster is Pd6(SC6H) 11 ) 12 It belongs to the triclinic crystal system and has the space group P-1.

[0031] Preferably, the Pd6(SR) 12 The crystallographic parameters of the cluster are: α=91.025(5), β=107.110(5), γ=104.164(5).

[0032] This invention provides the aforementioned octahedral Pd6(SR) structure. 12 The method for preparing clusters includes the following steps:

[0033] S1: Dissolve palladium salt in acetonitrile and stir for a period of time to obtain a brown solution A containing palladium ions.

[0034] S2: Add cyclohexanethiol to the brown solution A from step S1, and continue stirring the reaction for a period of time to obtain a yellow-brown solution B.

[0035] S3: Add the yellow-brown solution B from step S2 to triethylamine, stir the reaction, centrifuge the product to precipitate, and wash repeatedly to remove excess thiol to obtain yellow precipitate C.

[0036] S4: Dissolve the yellow precipitate C obtained in step S3 in an organic solvent, extract to obtain a red solution, separate by thin-layer chromatography, extract the separated product with an organic solvent, and culture it into single crystals to obtain Pd6(SR) with an octahedral structure. 12 Cluster.

[0037] Preferably, in step S1, the palladium salt is palladium acetate trimer.

[0038] Preferably, in step S1, the stirring rate is 600-1000 r / min and the stirring reaction time is 15-20 min.

[0039] Preferably, in step S2, the molar ratio of cyclohexylthiol to palladium ions is (1-12):1.

[0040] Preferably, in step S2, the stirring rate of the stirring reaction is 600-1000 r / min, and the stirring reaction time is 15-20 min.

[0041] Preferably, in step S3, the molar ratio of triethylamine to palladium ions is (1-8):1.

[0042] Preferably, in step S3, the stirring rate is 600-1000 r / min and the stirring reaction time is 6-10 h.

[0043] Preferably, in step S3, acetonitrile is used for centrifugal washing 1 to 5 times at a centrifugation speed of 10,000 rpm / min.

[0044] Preferably, in step S4, the organic solvents are dichloromethane and / or toluene.

[0045] The technical solution of the present invention will be elaborated and explained below with reference to specific actual data:

[0046] Example 1:

[0047] S1: At room temperature, add 10 mL of acetonitrile solvent to a 50 mL single-necked round-bottom flask, add 33 mg of palladium acetate trimer, and stir vigorously at 600 rpm for 15 min to dissolve the palladium acetate trimer.

[0048] S2: Add 100 μL of cyclohexylthiol to the solution after the reaction in step S1. A large amount of brownish-yellow flocculent precipitate quickly appears in the solution. Stir continuously at 600 rpm for 15 min.

[0049] S3: Add 100 μL of triethylamine solution to the solution obtained from step S2, and continue the reaction at room temperature for 6 hours. After the reaction is complete, centrifuge the product to precipitate it, and wash it repeatedly with acetonitrile to remove excess thiols and unreacted precursors and other impurities.

[0050] S4: After drying the reaction product obtained in step S3, extract it with dichloromethane solution to obtain a red solution. Separate the solution by thin-layer chromatography. Extract the separated and collected product with an organic solvent and grow yellow transparent single crystals by gas-phase diffusion, which are octahedral Pd6(SR). 12 Cluster.

[0051] Example 2:

[0052] S1: At room temperature, add 10 mL of acetonitrile solvent to a 50 mL single-necked round-bottom flask, add 100 mg of palladium acetate trimer, and stir vigorously at 600 rpm for 15 min to dissolve the palladium acetate trimer.

[0053] S2: Add 200 μL of cyclohexylthiol to the solution after the reaction in step S1. A large amount of brownish-yellow flocculent precipitate quickly appears in the solution. Stir continuously at 600 rpm for 15 min.

[0054] S3: Add 100 μL of triethylamine solution to the solution obtained from step S2, and continue the reaction at room temperature for 6 hours. After the reaction is complete, centrifuge the product to precipitate it, and wash it repeatedly with acetonitrile to remove excess thiols and unreacted precursors and other impurities.

[0055] S4: The reaction product obtained in S3 was dried and extracted with dichloromethane solution to obtain a red solution. The solution was separated by thin-layer chromatography. The separated and collected product was extracted with an organic solvent and grown into yellow transparent single crystals by gas-phase diffusion, which is octahedral Pd6(SR). 12 Cluster.

[0056] Example 3:

[0057] S1: At room temperature, add 10 mL of acetonitrile solvent to a 50 mL single-necked round-bottom flask, add 67 mg of palladium acetate trimer, and stir vigorously at 600 rpm for 15 min to dissolve the palladium acetate trimer.

[0058] S2: Add 400 μL of cyclohexylthiol to the solution after the reaction in step S1. A large amount of brownish-yellow flocculent precipitate quickly appears in the solution. Stir continuously at 600 rpm for 15 min.

[0059] S3: Add 100 μL of triethylamine solution to the solution obtained from step S2, and continue the reaction at room temperature for 6 hours. After the reaction is complete, centrifuge the product to precipitate it, and wash it repeatedly with acetonitrile to remove excess thiols and unreacted precursors and other impurities.

[0060] S4: The reaction product obtained in S3 was dried and extracted with dichloromethane solution to obtain a red solution. The solution was separated by thin-layer chromatography. The separated and collected product was extracted with an organic solvent and grown into yellow transparent single crystals by gas-phase diffusion, which is octahedral Pd6(SR). 12 Cluster.

[0061] Example 4:

[0062] S1: At room temperature, add 10 mL of acetonitrile solvent to a 50 mL single-necked round-bottom flask, add 67 mg of palladium acetate trimer, and stir vigorously at 600 rpm for 15 min to dissolve the palladium acetate trimer.

[0063] S2: Add 200 μL of cyclohexylthiol to the solution after the reaction in step S1. A large amount of brownish-yellow flocculent precipitate quickly appears in the solution. Stir continuously at 600 rpm for 15 min.

[0064] S3: Add 200 μL of triethylamine solution to the solution obtained from step S2, and continue the reaction at room temperature for 6 hours. After the reaction is complete, centrifuge the product to precipitate it, and wash it repeatedly with acetonitrile to remove excess thiols and unreacted precursors and other impurities.

[0065] S4: After drying the reaction product obtained in step S3, extract it with dichloromethane solution to obtain a red solution. Separate the solution by thin-layer chromatography. Extract the separated and collected product with an organic solvent and grow yellow transparent single crystals by gas-phase diffusion, which are octahedral Pd6(SR). 12 Cluster.

[0066] Octahedral Pd6(SR) prepared in Examples 1, 2, 3, and 4 12 The crystal structure of the cluster is as follows Figure 1 As shown. By Figure 1 It can be seen that the Pd6(SR) 12 The cluster is a palladium cluster protected by cyclohexylthiol ligands, containing 6 Pd atoms and 12 cyclohexylthiol ligands. The 6 Pd atoms form an octahedral core, and the sulfur atoms in the cyclohexylthiol ligands are connected to the Pd atoms on the periphery, with each sulfur atom connecting to two Pd atoms.

[0067] The crystal data of the crystals obtained in Example 1 are shown in Table 1 below:

[0068] Table 1: Octahedral Pd6(SR) 12 Crystal data of clusters

[0069]

[0070]

[0071] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention. It is neither necessary nor possible to exhaustively describe all embodiments here. However, obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. An octahedral Pd6(SR) structure 12 Clusters, characterized by: The Pd6(SR) 12 The cluster is a palladium cluster protected by cyclohexylthiol ligands, containing 6 Pd atoms and 12 cyclohexylthiol ligands. The 6 Pd atoms form an octahedral core, and the sulfur atoms in the cyclohexylthiol ligands are connected to the Pd atoms on the periphery, with each sulfur atom connecting to two Pd atoms.

2. The octahedral Pd6(SR) structure according to claim 1 12 Clusters, characterized by: The Pd6(SR) 12 The molecular formula of the cluster is Pd6(SC6H) 11 ) 12 It belongs to the triclinic crystal system and has the space group P-1.

3. The octahedral Pd6(SR) structure according to claim 2 12 Clusters, characterized in that, The Pd6(SR) 12 The crystallographic parameters of the cluster are: a=14.032(2)Å, b=17.246(2)Å, c=20.673(3)Å, α=91.025(5), β=107.110(5), γ=104.164(5).

4. A Pd6(SR) with an octahedral structure as described in any one of claims 1-3 12 The method for preparing clusters is characterized in that, Includes the following steps: S1: Dissolve palladium salt in acetonitrile and stir for a period of time to obtain a brown solution A containing palladium ions; S2: Add cyclohexanethiol to the brown solution A from step S1, and continue stirring the reaction for a period of time to obtain a yellow-brown solution B. S3: Add the yellow-brown solution B from step S2 to triethylamine, stir the reaction, centrifuge the product to precipitate, and wash repeatedly to remove excess thiol to obtain yellow precipitate C. S4: Dissolve the yellow precipitate C obtained in step S3 in an organic solvent, extract to obtain a red solution, separate by thin-layer chromatography, extract the separated product with an organic solvent, and culture it into single crystals to obtain Pd6(SR) with an octahedral structure. 12 Clusters; In step S1, the palladium salt is palladium acetate trimer.

5. The octahedral Pd6(SR) structure according to claim 4 12 The method for preparing clusters is characterized by: In step S1, the stirring rate is 600-1000 r / min, and the stirring reaction time is 15-20 min.

6. The octahedral Pd6(SR) structure according to claim 4 12 The method for preparing clusters is characterized by: In step S2, the molar ratio of cyclohexanethiol to palladium ions is (1-12):

1.

7. The octahedral Pd6(SR) structure according to claim 4 12 The method for preparing clusters is characterized by: In step S2, the stirring rate of the stirring reaction is 600-1000 r / min, and the stirring reaction time is 15-20 min.

8. The octahedral Pd6(SR) structure according to claim 4 12 The method for preparing clusters is characterized by: In step S3, the molar ratio of triethylamine to palladium ions is (1-8):

1.

9. The octahedral Pd6(SR) structure according to claim 4 12 The method for preparing clusters is characterized by: In step S3, the stirring rate of the stirring reaction is 600-1000 r / min, and the stirring reaction time is 6-10 h.

10. The octahedral Pd6(SR) structure according to claim 4 12 The method for preparing clusters is characterized by: In step S3, acetonitrile is used for centrifugal washing 1 to 5 times at a speed of 10,000 rpm.

11. The octahedral Pd6(SR) structure according to claim 4 12 The method for preparing clusters is characterized by: In step S4, the organic solvent is dichloromethane and / or toluene.

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