Copper hydride nanoclusters Cu 18 H9 and a high yield preparation method thereof

Abstract

The application discloses copper hydrogen nanoclusters Cu 18 H9 and a high-yield preparation method thereof. The copper hydrogen nanoclusters have a molecular formula of [Cu 18 H9Y7Z2]·X2, Y is a dehydrogenated nitrogen ligand, Z is a phosphorus ligand, and X is an anion. Thus, the copper hydrogen nanoclusters [Cu 18 H9Y7Z2]·X2 have a structure based on the phosphorus ligand and the nitrogen ligand and have the characteristic of surface vacancy sites, greatly improve structural stability of the copper hydrogen nanoclusters, and reduce sensitivity to air and humidity.

Description

Technical Field

[0001] This invention relates to the field of materials technology, specifically to a copper-hydrogen nanocluster Cu. 18 H9 and its high-yield preparation method. Background Technology

[0002] Over the past decade, significant progress has been made in the study of copper-hydrogen nanoclusters, thanks to the emergence of a series of novel structures. Research indicates that copper-hydrogen nanoclusters not only possess unique and novel structures but also have potential applications in catalysis, hydrogen storage and release, and CO2 fixation. For example, Cu nanoclusters with a "Chinese Puzzle" structure... 28 H 15 It can release hydrogen under various conditions, and can also replenish the hydrogen source to return to the original structure and continue to release hydrogen, thus achieving a cycle. 32 H 20 The ability to convert CO2 into formic acid at relatively low potentials is attributed to the different coordination modes H in its structure. － The synergistic effect between them. However, such copper-hydrogen nanoclusters, including Stryker reagents, still have significant limitations, such as high sensitivity to air and humidity and complex purification processes.

[0003] Therefore, further research on copper-hydrogen nanoclusters is needed. Summary of the Invention

[0004] The present invention aims to at least partially solve one of the technical problems in the related art.

[0005] In a first aspect, the present invention provides a copper-hydrogen nanocluster. According to an embodiment of the present invention, the molecular formula of the copper-hydrogen nanocluster is [Cu...]. 18 H9Y7Z2]·X2, where Y is the dehydrogenated nitrogen ligand, Z is the phosphorus ligand, and X is the anion. Therefore, this copper-hydrogen nanocluster [Cu]... 18 The structure of H9Y7Z2]·X2 is based on phosphorus and nitrogen ligands and has surface vacancy sites, which greatly improves the structural stability of copper-hydrogen nanoclusters and reduces their sensitivity to air and humidity.

[0006] According to an embodiment of the present invention, X is F - Cl - ,Br - ,ClO 4- PF 6- OTF - BF 4- 、SbF 6- NO 3- CH3COO - CF3SO3- At least one of them.

[0007] According to an embodiment of the present invention, the phosphorus ligand is (1,3-bis(diphenylphosphine)propane), and the nitrogen ligand is at least one of N,N′-bis(5-trifluoromethyl-2-pyridyl)formamidin, N,N′-bis(5-trichloromethyl-2-pyridyl)formamidin, N,N′-bis(5-tribromomethyl-2-pyridyl)formamidin, and N,N′-bis(5-triiodomethyl-2-pyridyl)formamidin.

[0008] In another aspect of the present invention, a method for preparing copper-hydrogen nanoclusters is proposed. The method for preparing copper-hydrogen nanoclusters includes the following steps: weighing a certain amount of Cu(CH3CN)4X, a phosphorus ligand, and a nitrogen ligand, wherein X is an anion; dissolving the Cu(CH3CN)4X, the phosphorus ligand, and the nitrogen ligand in a first solvent and stirring to obtain a first solution; adding an alkaline solvent to the first solution and stirring to obtain a second solution, the second solution being alkaline; adding a methanol solution of tert-butylamine borane to the second solution and stirring to obtain a third solution containing the copper-hydrogen nanoclusters. Therefore, the method for preparing copper-hydrogen nanoclusters is simple, has a high yield, and the synthesized structure is based on phosphorus and nitrogen ligands, possessing surface vacancy sites, and exhibiting good structural stability.

[0009] According to an embodiment of the present invention, the method for preparing copper-hydrogen nanoclusters further includes centrifuging and crystallizing the third solution to obtain copper-hydrogen nanoclusters crystals.

[0010] According to an embodiment of the present invention, the molar ratio of Cu(CH3CN)4X to the phosphorus ligand is 7.2 to 8.8:1, and the molar ratio of Cu(CH3CN)4X to the nitrogen ligand is 1.8 to 2.2:1.

[0011] According to an embodiment of the present invention, the first solvent is a mixture of dichloromethane and methanol, wherein the volume ratio of dichloromethane to methanol is 1.8 to 2.2:1.

[0012] According to an embodiment of the present invention, the alkaline solvent is triethylamine.

[0013] According to an embodiment of the present invention, the concentration of tert-butylamine borane in the methanol solution of the tert-butylamine borane is 0.15 to 0.25 mol / L, and the molar ratio of Cu(CH3CN)4X to the tert-butylamine borane is 1:1.8 to 2.2.

[0014] According to an embodiment of the present invention, all steps in preparing the copper-hydrogen nanoclusters were carried out in an air environment at 10°C to 40°C. Attached Figure Description

[0015] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0016] Figure 1 This is a single-crystal structure of copper-hydrogen nanoclusters in one embodiment of the present invention;

[0017] Figure 2 This is a schematic diagram of the core structure of a copper-hydrogen nanocluster in one embodiment of the present invention;

[0018] Figure 3 This is a flowchart of a method for preparing copper-hydrogen nanoclusters according to an embodiment of the present invention;

[0019] Figure 4 This is a flowchart of a method for preparing copper-hydrogen nanoclusters according to another embodiment of the present invention;

[0020] Figure 5 Mass spectrometry data of copper-hydrogen nanoclusters according to Example 1 of the present invention;

[0021] Figure 6 The image shows the ultraviolet absorption spectrum of copper-hydrogen nanoclusters in acetonitrile according to Example 1 of the present invention. Detailed Implementation

[0022] The embodiments of the present invention are described in detail below. These embodiments are exemplary and are only used to explain the present invention, and should not be construed as limiting the invention. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in the art or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all commercially available conventional products.

[0023] In a first aspect, the present invention provides a copper-hydrogen nanocluster. According to an embodiment of the invention, the molecular formula of the copper-hydrogen nanocluster is [Cu...]. 18 H9Y7Z2]·X2,[Cu 18 H9Y7Z2]·X2 (can be simply referred to as Cu) 18 H9), the overall single-crystal structure can be referenced. Figure 1 [Cu 18 The core structure Cu in H9Y7Z2]·X2 18 The crystal structure of H9 can be referenced. Figure 2 In the molecular formula, Y represents the dehydrogenated nitrogen ligand, Z represents the phosphorus ligand, and X represents the anion. Therefore, this copper-hydrogen nanocluster [Cu]... 18 The structure of H9Y7Z2]·X2 is based on phosphorus and nitrogen ligands and has surface vacancy sites, which greatly improves the structural stability of copper-hydrogen nanoclusters and reduces their sensitivity to air and humidity.

[0024] According to an embodiment of the present invention, the anion X is F. - Cl - ,Br - ,ClO 4- PF 6- OTF - BF 4- 、SbF 6- NO 3- CH3COO - CF3SO 3- At least one of them. Therefore, the above anion can react with [Cu]. 18 H9] 11+ They combine to form stable copper-hydrogen nanoclusters, ensuring the high catalytic activity of these nanoclusters.

[0025] According to an embodiment of the present invention, the phosphorus ligand is (1,3-bis(diphenylphosphine)propane), and the nitrogen ligand is at least one of N,N′-bis(5-trifluoromethyl-2-pyridyl)formamidin, N,N′-bis(5-trichloromethyl-2-pyridyl)formamidin, N,N′-bis(5-tribromomethyl-2-pyridyl)formamidin, and N,N′-bis(5-triiodomethyl-2-pyridyl)formamidin. Thus, the nitrogen ligand and phosphorus ligand can react with [Cu... 18 H9] 11+ They combine to form stable copper-hydrogen nanoclusters, ensuring the high catalytic activity of these nanoclusters.

[0026] In some embodiments, anion X is PF. 6- The phosphorus ligand is (1,3-bis(diphenylphosphine)propane) (abbreviated as DPPP), and the nitrogen ligand is N,N′-bis(5-trifluoromethyl-2-pyridyl)formamidinium (abbreviated as HTf-dpf). Therefore, the chemical formula of the copper-hydrogen nanoclusters is [Cu]. 18 H9(Tf-dpf)7(DPPP)2]·(PF6)2, where Tf-dpf is the product of HTf-dpf after dehydrogenation.

[0027] In another aspect of the invention, a method for preparing copper-hydrogen nanoclusters is provided. (Refer to...) Figure 3 The preparation method of copper-hydrogen nanoclusters includes the following steps:

[0028] S1: Weigh a certain amount of Cu(CH3CN)4X, phosphorus ligand and nitrogen ligand, wherein X is an anion.

[0029] In this step, X can be F - Cl - ,Br - ,ClO 4- PF 6- OTF- BF 4- 、SbF 6- NO 3- CH3COO - CF3SO 3- The phosphorus ligand can be (1,3-bis(diphenylphosphine)propane); the nitrogen ligand can be at least one of N,N′-bis(5-trifluoromethyl-2-pyridyl)formamidin, N,N′-bis(5-trichloromethyl-2-pyridyl)formamidin, N,N′-bis(5-tribromomethyl-2-pyridyl)formamidin, and N,N′-bis(5-triiodomethyl-2-pyridyl)formamidin. Therefore, the selection of the above materials provides copper atoms, anions, phosphorus ligands, and nitrogen ligands for the synthesis of copper-hydrogen nanoclusters, ensuring the synthesis of structurally stable copper-hydrogen nanoclusters based on phosphorus and nitrogen ligands.

[0030] According to embodiments of the present invention, the molar ratio of Cu(CH3CN)4X to phosphorus ligands can be 7.2–8.8:1, such as 7.2:1, 7.5:1, 7.8:1, 8.0:1, 8.2:1, 8.5:1, 8.8:1, etc.; the molar ratio of Cu(CH3CN)4X to nitrogen ligands can be 1.8–2.2:1, such as 1.8:1, 1.9:1, 2.0:1, 2.1:1, 2.2:1, etc. The inventors have found that by controlling the molar ratios of Cu(CH3CN)4X to phosphorus ligands and Cu(CH3CN)4X to nitrogen ligands within the above-mentioned ranges, phosphorus and nitrogen ligands can effectively stabilize and modify copper-hydrogen nanoclusters, which is beneficial to improving the stability of copper-hydrogen nanoclusters; moreover, the reaction efficiency of Cu(CH3CN)4X with phosphorus and nitrogen ligands can be maximized without causing excessive waste of one of the raw materials.

[0031] S2: Dissolve Cu(CH3CN)4X, phosphorus ligand and nitrogen ligand in the first solvent and stir to obtain the first solution.

[0032] In some embodiments, the first solvent is a mixture of dichloromethane and methanol, with a volume ratio of dichloromethane to methanol of 1.8–2.2:1, such as 1.8:1, 1.9:1, 2.0:1, 2.1:1, or 2.2:1. Thus, under the aforementioned selected volume ratio conditions, the first solvent can dissolve and uniformly disperse Cu(CH3CN)4X, the phosphorus ligand, and the nitrogen ligand, thereby effectively ensuring the homogeneity and reaction rate of subsequent reactions. Furthermore, the stirring time in this step can be 5–15 minutes.

[0033] S3: Add an alkaline solvent to the first solution and stir to obtain a second solution, which is alkaline.

[0034] In some embodiments, the alkaline solvent is triethylamine. Thus, the addition of the alkaline solvent neutralizes the hydrogen ions (hydrogen ions in the nitrogen ligands) in the system, and the excess addition of the alkaline solvent makes the final second solution alkaline, thereby providing the alkaline environment required for the synthesis of copper-hydrogen nanoclusters.

[0035] The amount of alkaline solution added can be calculated by those skilled in the art based on actual conditions, and may be added in excess as appropriate, as long as it meets the process requirements of this invention. Additionally, the stirring time in this step can be 5–15 minutes.

[0036] S4: Add a methanol solution of tert-butylamine borane to the second solution and stir to obtain a third solution containing copper-hydrogen nanoclusters.

[0037] In embodiments of the present invention, the concentration of tert-butylamine borane in the methanol solution is 0.15–0.25 mol / L (e.g., 0.15 mol / L, 0.18 mol / L, 0.2 mol / L, 0.23 mol / L, 0.25 mol / L), and the molar ratio of Cu(CH3CN)4X to tert-butylamine borane can be 1:1.8–2.2, e.g., 1:1.8, 1:1.9, 1:2.0, 1:2.1, 1:2.2, etc. Therefore, within the above parameter range, tert-butylamine borane, as a reducing agent, can fully undergo the reduction reaction, and tert-butylamine borane provides hydride anions to the copper-hydrogen nanoclusters, thereby preparing copper-hydrogen nanoclusters through the reduction reaction. Specifically, after adding the methanol solution of tert-butylamine borane to the second solution, the solution gradually changes color, which is the final third solution obtained.

[0038] According to an embodiment of the present invention, referring to Figure 4 Other methods for preparing copper-hydrogen nanoclusters include:

[0039] S5: The third solution is centrifuged and crystallized to obtain copper-hydrogen nanoclusters in crystal form.

[0040] In some specific embodiments, the third solution is centrifuged, the supernatant is collected, and the solution is diffused in a test tube with a solvent. After crystallization for 3 to 7 days, copper-hydrogen nanoclusters are obtained.

[0041] There are no special requirements for the specific method of the centrifugation process described above. Those skilled in the art can choose flexibly according to the actual situation, as long as it can meet the process requirements of the present invention.

[0042] Furthermore, there are no special requirements regarding the specific type of solvent used for test tube diffusion. Those skilled in the art can choose flexibly according to the actual situation, as long as it meets the process requirements of the present invention. In some embodiments, the solvent includes, but is not limited to, at least one of n-hexane, n-pentane, and diethyl ether.

[0043] According to an embodiment of the present invention, all steps S1 to S5 are performed in an air environment at a temperature of 10°C to 40°C. Therefore, copper-hydrogen nanoclusters can be synthesized under normal temperature and pressure air conditions, further demonstrating that the preparation method of the present invention is simple and avoids complex process conditions.

[0044] According to embodiments of the present invention, the copper-hydrogen nanoclusters [Cu] synthesized by the above method in the present invention 18 The structure of H9Y7Z2]·X2 is based on phosphorus and nitrogen ligands and has surface vacancy sites, which greatly improves the structural stability of copper-hydrogen nanoclusters and reduces their sensitivity to air and humidity. Furthermore, it can be synthesized in an air environment at temperatures ranging from 10°C to 40°C, allowing the synthesis reaction to proceed at room temperature and pressure. This significantly reduces the technological difficulty of synthesizing copper-hydrogen nanoclusters in this invention. Moreover, the preparation of copper-hydrogen nanoclusters [Cu... 18 The yield of H9Y7Z2]·X2 is relatively high. In some embodiments, copper-hydrogen nanoclusters [Cu] are prepared. 18 The yield of H9Y7Z2]·X2 can be as high as 80% or more, and can even reach 82%.

[0045] The embodiments of the present invention are described in detail below. It should be noted that the embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention. In addition, unless otherwise specified, all reagents used in the following embodiments are commercially available or can be synthesized according to the methods described herein or known to others. For reaction conditions not listed, they are also readily available to those skilled in the art.

[0046] Example

[0047] Example 1

[0048] Copper-hydrogen nanoclusters were prepared according to the following method:

[0049] (1) Under normal temperature and pressure air conditions, weigh out the following: copper tetraacetonitrile hexafluorophosphate (Cu(CH3CN)4PF6): 74 mg, 0.2 mmol; N,N′-bis(5-trifluoromethyl-2-pyridyl)formamidinium (HTf-dpf): 22.6 mg, 0.1 mmol; 1,3-bis(diphenylphosphine)propane (DPPP): 11 mg, 0.025 mmol.

[0050] (2) Under normal temperature and pressure air conditions, add 3.0 mL of dichloromethane (CH2Cl2) / methanol (CH3OH) (V(CH2Cl2):V(CH3OH)=2:1) solution, stir for 10 minutes to obtain the first solution;

[0051] (3) Under normal temperature and pressure air conditions, excess triethylamine (C6H) was then added to the first solution. 15 N)(20uL), stir for 10 minutes to obtain the second solution;

[0052] (4) Under normal temperature and pressure air conditions, 2.0 mL of methanol solution of tert-butylamine borane (34.8 mg, 0.4 mmol) was added to the second solution. The solution gradually turned orange-red, and a third solution containing copper-hydrogen nanoclusters was obtained.

[0053] (5) After stirring the third solution for 2.5 hours, centrifuge and collect the orange-red supernatant. Diffusion in a test tube is then performed using n-hexane. Five days later, a large amount of wine-red copper-hydrogen nanoclusters ([Cu)) were obtained. 18 H9(Tf-dpf)7(DPPP)2]·(PF6)2), with a yield of 82%.

[0054] The single-crystal structure and core structure diagram of the copper-hydrogen nanoclusters synthesized in Example 1 can be found in [reference]. Figure 1 and 2 Mass spectrometry data can be referenced. Figure 5 ,Depend on Figure 5 As can be seen, its mass spectrometry data shows only one divalent peak, located at m / z = 2182.8, corresponding to the molecular ion peak [Cu]. 18 H9(Tf-dpf)7(DPPP)2] 2+ The measured data and the theoretical calculation data are in good agreement; [Cu 18 The UV absorption spectrum of H9(Tf-dpf)7(DPPP)2]·(PF6)2 in acetonitrile can be found in [reference]. Figure 6 ,Depend on Figure 6 It can be seen that there are two strong absorption peaks in the ultraviolet absorption data, located near 270 nm and 340 nm, respectively, which correspond to electronic transitions within the ligand.

[0055] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0056] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A copper-hydrogen nanocluster, characterized in that, The molecular formula of the copper-hydrogen nanoclusters is [Cu 18 [H9Y7Z2]·X2, where Y is the dehydrogenated nitrogen ligand, Z is the phosphorus ligand, and X is the anion. The phosphorus ligand is 1,3-bis(diphenylphosphine)propane. The nitrogen ligand is at least one of N,N′-bis(5-trifluoromethyl-2-pyridyl)formamidin, N,N′-bis(5-trichloromethyl-2-pyridyl)formamidin, N,N′-bis(5-tribromomethyl-2-pyridyl)formamidin, and N,N′-bis(5-triiodomethyl-2-pyridyl)formamidin.

2. The copper-hydrogen nanoclusters according to claim 1, characterized in that, X is F - Cl - ,Br - ClO4 - PF6 - OTF - BF4 - SbF6 - NO3 - CH3COO - CF3SO3 - At least one of them.

3. A method for preparing copper-hydrogen nanoclusters according to any one of claims 1 to 2, characterized in that, Includes the following steps: Weigh out a certain amount of Cu(CH3CN)4X, phosphorus ligand and nitrogen ligand, wherein X is an anion; The Cu(CH3CN)4X, the phosphorus ligand, and the nitrogen ligand are dissolved in a first solvent and stirred to obtain a first solution; An alkaline solvent is added to the first solution and stirred to obtain a second solution, which is alkaline. A methanol solution of tert-butylamine borane was added to the second solution and stirred to obtain a third solution containing the copper-hydrogen nanoclusters.

4. The method according to claim 3, characterized in that, It also includes centrifuging and crystallization of the third solution to obtain copper-hydrogen nanoclusters in crystal form.

5. The method according to claim 3, characterized in that, The molar ratio of Cu(CH3CN)4X to the phosphorus ligand is 7.2~8.8:

1. Optionally, the molar ratio of Cu(CH3CN)4X to the nitrogen ligand is 1.8 to 2.2:

1.

6. The method according to claim 3, characterized in that, The first solvent is a mixture of dichloromethane and methanol, wherein the volume ratio of dichloromethane to methanol is 1.8~2.2:

1.

7. The method according to claim 3, characterized in that, The alkaline solvent is triethylamine.

8. The method according to claim 3, characterized in that, The concentration of tert-butylamine borane in the methanol solution of the tert-butylamine borane is 0.15~0.25 mol / L, and the molar ratio of Cu(CH3CN)4X to the tert-butylamine borane is 1:1.8~2.

2.

9. The method according to any one of claims 3 to 8, characterized in that, All steps in the preparation of the copper-hydrogen nanoclusters were carried out in an air environment at 10°C to 40°C.

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