Copper Hydrogen Nanoclusters Cu 20 H 9 Preparation method and catalytic application thereof

Abstract

The present invention provides a copper hydrogen nanocluster Cu 20 H9 and its preparation method and catalytic application. The molecular formula of the copper hydrogen nanocluster is [Cu 20 H9Y 10 ]·X, Y are nitrogen ligands after dehydrogenation, and X is an anion. Thus, the copper hydrogen nanocluster has good stability and high catalytic activity, especially for the catalysis of 4-nitrophenol. In some embodiments, the catalytic efficiency of the copper hydrogen nanocluster for 4-nitrophenol can be as high as more than 99%.

Description

Technical Field

[0001] The present invention relates to the field of material technology, and in particular to copper hydrogen nanoclusters Cu 20 H9 and its preparation method and catalytic application. Background Art

[0002] Structurally precise nanoclusters of coinage metals (gold, silver, copper, etc.) have attracted extensive attention from scientific researchers due to their rich structures and unique physical and chemical properties. These nanocluster materials have shown good application prospects in many fields such as catalysis, sensing, medicine, energy conversion, and optoelectronics.

[0003] Compared with gold and silver nanoclusters, copper clusters have a long history. In 1988, the Stryker group reported the synthesis of [(Ph3P)CuH]6 (Stryker reagent). This copper hydrogen nanocluster can efficiently catalyze the reduction of carbonyl derivatives. Due to mild reaction conditions, good functional group compatibility and excellent overall efficiency, Stryker reagent was named "Reagent of the Year" in 1991. Subsequently, [CuH(L)]6 copper hydrogen nanoclusters based on different phosphine ligands were widely synthesized and used as effective catalysts for various catalytic reduction and hydrogenation reactions. Today, a variety of copper hydrogen catalytic chemical reactions including hydrosilylation, hydroboration, and hydroamination have been widely studied. However, this type of copper hydrogen catalyst has the disadvantages of difficult synthesis and poor stability, and the H in its structure － It is difficult to accurately locate them, and obtaining copper-hydrogen nanoclusters with atomically precise structures over a long period of time has become one of the difficulties of this research.

[0004] Therefore, the research on copper-hydrogen nanoclusters needs to be further deepened. Summary of the invention

[0005] The present invention aims to solve one of the technical problems in the related art at least to a certain extent. To this end, one object of the present invention is to provide a copper-hydrogen nanocluster with a stable structure or high catalytic activity.

[0006] In one aspect of the present invention, 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 20 H9Y 10 ]·X(Cu 20 H9), Y is a nitrogen ligand after dehydrogenation, and X is an anion. Thus, the copper hydrogen nanocluster has good stability and high catalytic activity, especially for the catalysis of 4-nitrophenol. In some embodiments, the catalytic efficiency of the copper hydrogen nanocluster for 4-nitrophenol can be as high as 99% or more.

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

[0008] According to an embodiment of the present invention, the anion is F - , Cl - Br - , ClO 4- PF 6- 、OTF - , BF 4- , SbF 6- 、NO 3- 、CH3COO - CF3SO 3- At least one of .

[0009] In another aspect of the present invention, the present invention provides a method for preparing the aforementioned copper hydrogen nanoclusters. According to an embodiment of the present invention, the method for preparing copper hydrogen nanoclusters includes: weighing a certain amount of Cu(CH3CN)4X and a nitrogen ligand; dissolving the Cu(CH3CN)4X and the nitrogen ligand in a first solvent, and stirring under ice bath conditions to obtain a first solution; adding an alkaline solvent to the first solution, stirring to obtain a second solution, the second solution is alkaline; adding a methanol solution of tert-butylamine borane to the second solution, stirring to obtain a third solution containing the copper hydrogen nanoclusters. As a result, the copper hydrogen nanoclusters prepared by the above method have good stability and high catalytic activity, especially for the catalysis of 4-nitrophenol. In some embodiments, the catalytic efficiency of the copper hydrogen nanoclusters for 4-nitrophenol can be as high as 99% or more; moreover, the above method for synthesizing copper hydrogen nanoclusters is simple and has a high yield.

[0010] According to an embodiment of the present invention, the method for preparing copper-hydrogen nanoclusters further comprises centrifuging and crystallizing the third solution to obtain crystals of the copper-hydrogen nanoclusters.

[0011] According to an embodiment of the present invention, the molar ratio of the Cu(CH3CN)4X to the nitrogen ligand is 1.8-2.2:1.

[0012] According to an embodiment of the present invention, the first solvent is dichloromethane, and 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 tert-butylamine borane is 0.09-0.11 mol / L, and the molar ratio of the Cu(CH3CN)4X to the tert-butylamine borane is 1:0.8-1.2.

[0014] According to an embodiment of the present invention, all steps of preparing the copper-hydrogen nanoclusters are performed in an air environment at 10° C. to 40° C.

[0015] In another aspect of the present invention, the present invention provides an application of the aforementioned copper hydrogen nanocluster in catalyzing 4-nitrophenol. Thus, the copper hydrogen nanocluster has a high catalytic activity for 4-nitrophenol. In some embodiments, the catalytic efficiency of the copper hydrogen nanocluster for 4-nitrophenol can be as high as 99% or more. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0017] Figure 1 is a schematic diagram of a single crystal structure of a copper hydrogen nanocluster in one embodiment of the present invention;

[0018] Figure 2 is a flow chart of a method for preparing copper hydrogen nanoclusters in another embodiment of the present invention;

[0019] Figure 3 is a flow chart of a method for preparing copper hydrogen nanoclusters in another embodiment of the present invention;

[0020] Figure 4 is a reaction equation for catalytic reduction of 4-nitrophenol to 4-aminophenol by copper hydrogen nanoclusters in another embodiment of the present invention;

[0021] Figure 5 is a physical photograph of the third solution containing copper hydrogen nanoclusters in Example 1;

[0022] Figure 6 is a crystal photograph of the copper hydrogen nanocluster in Example 1;

[0023] Figure 7 is the mass spectrum of the copper hydrogen nanoclusters in Example 1;

[0024] Figure 8 is the ultraviolet absorption spectrum of the copper hydrogen nanoclusters in Example 1;

[0025] Fig. 9 is the X-ray photoelectron spectrum of the copper hydrogen nanoclusters in Example 1;

[0026] Fig.10 is the copper hydrogen nanocluster in Example 11 H NMR spectrum;

[0027] Fig.11 is the copper hydrogen nanocluster in Example 1 19 F NMR spectrum;

[0028] Fig.12 This is the ultraviolet absorption spectrum of the copper hydrogen nanoclusters catalyzing the reaction of 4-nitrophenol in Example 1. DETAILED DESCRIPTION

[0029] The scheme of the present invention will be explained below in conjunction with the embodiments. It will be appreciated by those skilled in the art that the following embodiments are only used to illustrate the present invention and should not be considered as limiting the scope of the present invention. Where specific techniques or conditions are not indicated in the embodiments, the techniques or conditions described in the literature in this area or the product specifications are used. The reagents or instruments used are not indicated by the manufacturer and are all conventional products that can be obtained commercially.

[0030] The present invention is described below with reference to specific embodiments. It should be noted that these embodiments are merely illustrative and do not limit the present invention in any way.

[0031] In one aspect of the present invention, 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 20 H9Y 10 ]·X(can be referred to as Cu 20 H9), Y is a nitrogen ligand after dehydrogenation, and X is an anion. Thus, the copper hydrogen nanocluster has good stability and high catalytic activity, especially for the catalysis of 4-nitrophenol. In some embodiments, the catalytic efficiency of the copper hydrogen nanocluster for 4-nitrophenol can be as high as 99% or more.

[0032] According to an embodiment of the present invention, the copper hydrogen nanoclusters [Cu 20 H9Y 10 ]·The single crystal structure diagram of X can be found in Figure 1 ,in, Figure 1 (a) indicates [Cu 20 H9Y 10 ]·Cu in X 12 The crystal structure of the unit cell, Figure 1 (b) in the figure indicates [Cu 20 H9Y 10 ]·Cu in X 12 The crystal structure of the +2Cu4 unit, Figure 1 (c) in the equation represents [Cu 20 H9Y 10 ]·X in [Cu 20 H9]11+ The crystal structure of Figure 1 (d) indicates [Cu 20 H9Y 10 ]·Cu in X 20 The overall crystal structure of H9. It can be seen from this that the copper hydrogen nanocluster of the present invention [Cu 20 H9Y 10 ]·X has good chemical stability.

[0033] According to an embodiment of the present invention, the nitrogen ligand is at least one of N,N′-bis(5-trifluoromethyl-2-pyridyl)formamidine (can be referred to as HTf-dpf), N,N′-bis(5-trichloromethyl-2-pyridyl)formamidine, N,N′-bis(5-tribromomethyl-2-pyridyl)formamidine, and N,N′-bis(5-triiodomethyl-2-pyridyl)formamidine. Thus, the nitrogen ligand can be combined with [Cu 20 H9] 11+ Combined into stable copper-hydrogen nanoclusters, and ensure the high catalytic activity of the copper-hydrogen nanoclusters.

[0034] According to an embodiment of the present invention, the anion is F - , Cl - Br - , ClO 4- PF 6- 、OTF - , BF 4- , SbF 6- 、NO 3- 、CH3COO - CF3SO 3- Thus, the above anions can be combined with [Cu 20 H9] 11+ Combined into stable copper-hydrogen nanoclusters, and ensure the high catalytic activity of the copper-hydrogen nanoclusters.

[0035] In some embodiments, the nitrogen ligand is N,N′-bis(5-trifluoromethyl-2-pyridyl)formamidine (abbreviated as HTf-dpf), and the anion is BF 4- , then the chemical formula of the copper hydrogen nanocluster is [Cu 20 H9(Tf-dpf) 10 ]·BF4, Tf-dpf is the product of HTf-dpf dehydrogenation.

[0036] In another aspect of the present invention, the present invention provides a method for preparing the aforementioned copper hydrogen nanoclusters. Figure 2 , the method for preparing copper hydrogen nanoclusters comprises:

[0037] S100: Weigh a certain amount of Cu(CH3CN)4X and nitrogen ligand.

[0038] According to an embodiment of the present invention, in the above steps, the molar ratio of Cu(CH3CN)4X to nitrogen ligand is 1.8 to 2.2:1 (e.g., 1.8:1, 1.9:1, 2.0:1, 2.1:1 or 2.2:1). Thus, the above ratio of Cu(CH3CN)4X to nitrogen ligand, the nitrogen ligand can stabilize and modify the copper hydrogen nanoclusters well, which is beneficial to improve the stability of the copper hydrogen nanoclusters; it can also maximize the reaction efficiency of Cu(CH3CN)4X and nitrogen ligands, and will not cause excessive waste of one of the raw materials.

[0039] S200: dissolving Cu(CH3CN)4X and the nitrogen ligand in a first solvent and stirring the mixture under an ice bath condition to obtain a first solution. Thus, the synthesis reaction can be effectively carried out smoothly under an ice bath condition.

[0040] According to an embodiment of the present invention, the first solvent is dichloromethane. In this way, under ice bath conditions, the solvent can dissolve Cu(CH3CN)4X and nitrogen ligands well, ensure the smooth progress of the synthesis reaction, and ensure a good reaction rate. Wherein, the above stirring time under ice bath conditions can be 5 to 15 minutes. In addition, the amount of the first solvent can be flexibly selected by those skilled in the art according to actual conditions, as long as Cu(CH3CN)4X and nitrogen ligands can be effectively dissolved, but it should not be excessive, resulting in low concentrations of each component in the solution. In some embodiments, 1mmol of Cu(CH3CN)4X can correspond to the addition of 13 to 18mL of the first solvent.

[0041] S300: adding an alkaline solvent to the first solution and stirring to obtain a second solution, the second solution being alkaline. Those skilled in the art will appreciate that since an alkaline solvent is added to the first solution, this step is still mixed under ice bath conditions.

[0042] In some embodiments, the alkaline solvent is triethylamine. Thus, the addition of the alkaline solvent can neutralize the hydrogen ions in the system (the hydrogen ions in the nitrogen ligands), achieve the dehydrogenation of the nitrogen ligands, and the excessive addition of the alkaline solvent makes the final second solution alkaline, thereby providing an alkaline environment required for the synthesis of copper hydrogen nanoclusters, and the triethylamine will not react with other reaction reagents or raw materials.

[0043] The amount of alkaline solution added can be calculated by a person skilled in the art according to the actual situation and added in an appropriate excess amount as long as the use requirements of the process of the present invention are met. In some embodiments, 1 mmol of Cu(CH3CN)4X can be added with 90 to 120 uL of triethylamine. In addition, the stirring time in this step can be 5 to 15 minutes.

[0044] S400: adding a methanol solution of tert-butylamine borane to the second solution, stirring, and obtaining a third solution containing copper hydrogen nanoclusters. Those skilled in the art will appreciate that since the methanol solution of tert-butylamine borane is added to the second solution, this step is still mixed under ice bath conditions.

[0045] According to an embodiment of the present invention, the concentration of tert-butylamine borane in the methanol solution of tert-butylamine borane is 0.09-0.11 mol / L (for example, 0.09 mol / L, 0.1 mol / L, 0.11 mol / L), and the molar ratio of Cu(CH3CN)4X to tert-butylamine borane is 1:0.8-1.2 (for example, 1:0.8, 1:0.9, 1:1, 1:1.1, 1:1.2, etc.). Thus, within the above parameter range, tert-butylamine borane can fully undergo a reduction reaction as a reducing agent, and tert-butylamine borane provides hydrogen anions for copper hydrogen nanoclusters, thereby preparing copper hydrogen nanoclusters through a reduction reaction. Among them, after adding the methanol solution of tert-butylamine borane to the second solution, the color of the solution gradually changes to wine red, that is, the third solution finally obtained is wine red.

[0046] There is no special requirement for the amount of methanol solution of tert-butylamine borane, and those skilled in the art can flexibly select it according to the actual situation of the specific reaction. In some embodiments, 1 mmol of Cu(CH3CN)4X can be added to 15-25 mL of methanol solution of tert-butylamine borane. In addition, the stirring time in this step can be 3-4 hours.

[0047] According to an embodiment of the present invention, referring to Figure 3 The method for preparing copper-hydrogen nanoclusters further includes S500: centrifuging and crystallizing the third solution to obtain crystals of copper-hydrogen nanoclusters.

[0048] In some specific embodiments, the third solution is spin-dried to remove the solvent, a certain amount of CH2Cl2 solution is added, and test tube diffusion is performed to obtain crystals, i.e., crystals of copper hydrogen nanoclusters. There are no special requirements for the specific type of solvent used in the test tube diffusion, and those skilled in the art can flexibly select it according to actual conditions, as long as it can meet the use requirements of the process of the present invention. In some embodiments, the solvent includes but is not limited to at least one of n-hexane, n-pentane and ether; the test tube diffusion time can be 2 to 6 days.

[0049] According to the embodiment of the present invention, the above steps S100 to S500 are all performed in an air environment at 10° C. to 40° C. Thus, copper hydrogen nanoclusters can be synthesized under normal temperature and pressure air conditions, further illustrating that the preparation method of the present invention is simple and avoids complex process conditions.

[0050] According to the embodiments of the present invention, the copper hydrogen nanoclusters prepared by the above method have good stability and high catalytic activity, especially for the catalysis of 4-nitrophenol. In some embodiments, the catalytic efficiency of the copper hydrogen nanoclusters for 4-nitrophenol can be as high as 99% or more; moreover, the synthesis can be carried out in an air environment at 10°C to 40°C, so the synthesis reaction can be carried out at room temperature and pressure, which greatly reduces the process difficulty of synthesizing the copper hydrogen nanoclusters of the present invention, and the preparation of the copper hydrogen nanoclusters [Cu 20 H9Y 10 The yield of ]·X is relatively high, up to more than 50%.

[0051] In another aspect of the present invention, the present invention provides a use of the aforementioned copper hydrogen nanocluster in catalyzing 4-nitrophenol. In some embodiments, the catalytic efficiency of the copper hydrogen nanocluster on 4-nitrophenol can be as high as 99% or more, and the catalytic reaction time is short.

[0052] In some specific embodiments, the step of catalyzing 4-nitrophenol with copper hydrogen nanoclusters includes: adding a certain amount of copper hydrogen nanoclusters to an aqueous solution of 4-nitrophenol, stirring at room temperature, and adding a NaBH4 aqueous solution to the mixture of the copper hydrogen nanoclusters and the aqueous solution of 4-nitrophenol under continuous stirring to catalytically reduce 4-nitrophenol to 4-aminophenol. The reaction equation can be referred to Figure 4 , the catalytic reaction can be completed in a short time and the catalytic efficiency is extremely high.

[0053] Example

[0054] Example 1

[0055] The steps of preparing copper hydrogen nanoclusters (the following steps are all carried out at room temperature and pressure) include:

[0056] S100: Weigh Cu(CH3CN)4BF4 (63 mg, 0.2 mmol) and nitrogen ligand HTf-dpf (0.1 mmol, 33.4 mg);

[0057] S200: Dissolve Cu(CH3CN)4BF4 and HTf-dpf in 3.0 mL CH2Cl2 and stir in an ice bath for 10 minutes to obtain a first solution;

[0058] S300: add 20uL of triethylamine to the first solution, continue stirring for 10 minutes, and obtain a second solution, which is alkaline;

[0059] S400: 2.0 mL of methanol solution of tert-butylamine borane (0.2 mmol, 17.4 mg) was added to the second solution, and the solution gradually turned into a wine red clear liquid. The solution was stirred for 3.5 hours to obtain a third solution containing copper hydrogen nanoclusters. The actual photo of the third solution containing copper hydrogen nanoclusters can be found in Figure 5 ;

[0060] S500: The third solution was spin-dried to remove the solvent, 3.0 mL of CH2Cl2 solution was added, and the mixture was diffused in a test tube with n-hexane. After three days, wine red crystals were obtained, i.e., crystals of copper hydrogen nanoclusters [Cu 20 H9(Tf-dpf) 10 ]·BF4, the yield is 27.4mg, the yield is 57% (calculated based on copper), the crystal photo can be referred to Figure 6 .

[0061] Mass spectrometry analysis of the crystals of copper hydrogen nanoclusters, such as Figure 7 As shown, the mass spectrum shows: [Cu 20 H9(Tf-dpf) 10 The signals of [Cu]·BF4 at m / z=4612.2 and m / z=2337.6 correspond to [Cu 20 H9(Tf-dpf) 10 ] + (correspond Figure 7 M + ) and [Cu 21 H9(Tf-dpf) 10 ] 2+ (correspond Figure 7 [M+Cu] 2+ ), the isotope pattern of the observed molecular ion peaks is in good agreement with the simulated ones.

[0062] The crystals of copper hydrogen nanoclusters were tested for ultraviolet absorption spectra, such as Figure 8 As shown, the ultraviolet absorption spectrum shows that the copper hydrogen nanocluster exhibits strong absorption of ultraviolet light at 246nm, 262nm and 338nm.

[0063] XPS test of the crystals of copper hydrogen nanoclusters, such as Fig. 9 As shown, X-ray photoelectron spectroscopy (XPS) shows that the copper hydrogen nanoclusters exhibit Cu 2p at 952.4eV and 932.7eV, respectively. 1 / 2 and 2p 3 / 2 The peaks, separated by 19.7 eV, indicate the presence of Cu(I) (i.e., cuprous ions).

[0064] The crystals of copper hydrogen nanoclusters were tested by nuclear magnetic resonance. 1H NMR spectrum Fig.10 As shown, 1 H NMR spectrum shows that copper hydrogen nanoclusters [Cu 20 H9(Tf-dpf) 10 ]·The μ4-H and μ6-H signals in the BF4 structure are located at 3.91ppm and 10.69ppm, respectively, with a ratio of 2:1; the NMR signals of the six μ5-H ligands in its structure are located between 6.29-9.45ppm.

[0065] The crystals of copper hydrogen nanoclusters were tested by nuclear magnetic resonance. 19 F NMR spectrum Fig.11 As shown, 19 The F NMR spectrum shows that the pairing symmetry in the copper-hydrogen nanoclusters is low.

[0066] Example 2

[0067] The copper hydrogen nanoclusters obtained in Example 1 were used to catalyze 4-nitrophenol. The specific steps were as follows: 1 mg of the copper hydrogen nanoclusters was added to an aqueous solution of 4-nitrophenol (1 mL, 4-nitrophenol was 20 mmol), stirred at room temperature for 10 minutes, and 1 mL of a NaBH4 aqueous solution (1.0 mmol, 38 mg) was added to the mixture of the copper hydrogen nanoclusters and the aqueous solution of 4-nitrophenol under continuous stirring to rapidly catalyze the reduction of 4-nitrophenol to 4-aminophenol. The reaction was completed within 10 seconds. The catalytic reaction was monitored by ultraviolet absorption spectroscopy, as shown in FIG. Fig.12 shown.

[0068] The progress of the reaction was tracked by monitoring the change in the peak intensity of p-nitrophenol at 400 nm over time through UV-Vis absorption spectroscopy. Fig.12 As shown. Under the catalytic action of copper hydrogen nanoclusters, the absorption peak intensity of 4-NP at 400nm rapidly decreased and even disappeared, and it was completely converted into p-aminophenol (λ max水中 =295nm), the color of the reaction solution changed from yellow to colorless, and the reaction yield was 100%, that is, the catalytic efficiency was 100%.

[0069] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0070] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

[0071] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary 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 nanocluster is [Cu 20 H9Y 10 ]·X, Y are nitrogen ligands after dehydrogenation, X is an anion, The nitrogen ligand is at least one of N,N′-bis(5-trifluoromethyl-2-pyridyl)formamidine, N,N′-bis(5-trichloromethyl-2-pyridyl)formamidine, N,N′-bis(5-tribromomethyl-2-pyridyl)formamidine and N,N′-bis(5-triiodomethyl-2-pyridyl)formamidine. The anion is F - , Cl - Br - 、ClO4 - PF6 - 、OTF - 、BF4 - 、SbF6 - 、NO3 - 、CH3COO - CF3SO3 - At least one of .

2. A method for preparing the copper-hydrogen nanoclusters according to claim 1, characterized in that: include: Weigh a certain amount of Cu(CH3CN)4X and nitrogen ligand; Dissolving the Cu(CH3CN)4X and the nitrogen ligand in a first solvent and stirring under ice bath conditions to obtain a first solution; adding an alkaline solvent to the first solution and stirring to obtain a second solution, wherein the second solution is alkaline; A methanol solution of tert-butylamine borane is added to the second solution, and the mixture is stirred to obtain a third solution containing the copper hydrogen nanoclusters.

3. The method according to claim 2, characterized in that The method also includes centrifuging and crystallizing the third solution to obtain crystals of the copper-hydrogen nanoclusters.

4. The method according to claim 2 or 3, characterized in that: The molar ratio of the Cu(CH3CN)4X to the nitrogen ligand is 1.8-2.2:

1.

5. The method according to claim 2 or 3, characterized in that: The first solvent is dichloromethane, and the alkaline solvent is triethylamine.

6. The method according to claim 2 or 3, characterized in that: The concentration of tert-butylamine borane in the methanol solution of tert-butylamine borane is 0.09-0.11 mol / L, and the molar ratio of Cu(CH3CN)4X to tert-butylamine borane is 1:0.8-1.

2.

7. The method according to claim 2 or 3, characterized in that: All steps of preparing the copper hydrogen nanoclusters are carried out in an air environment at 10° C. to 40° C.

8. Use of the copper hydrogen nanoclusters according to claim 1 in catalyzing 4-nitrophenol.

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