Silver-based alloy nanocluster and application thereof in selective oxidative coupling reaction of photocatalytic benzylamine
By supporting the silver-based alloy nanocluster catalyst Pt2Ag23/TiO2, the problem of catalyst recovery and recycling in the selective oxidative coupling reaction of benzylamine was solved, achieving a highly efficient and environmentally friendly catalytic effect.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- ANHUI UNIV
- Filing Date
- 2026-01-04
- Publication Date
- 2026-04-21
AI Technical Summary
Existing technologies for selective oxidative coupling of benzylamine involve harsh catalyst conditions, numerous byproducts, and difficulty in catalyst recovery. Furthermore, traditional photocatalysts cannot be recycled, resulting in low reaction efficiency and environmental pollution.
Silver-based alloy nanoclusters [Pt2Ag23(PPh3)10Cl7] were supported on a titanium dioxide support to form a supported catalyst Pt2Ag23/TiO2, which was used for the photocatalytic selective oxidative coupling reaction of benzylamine, and the reaction was driven by a 365 nm LED lamp.
It achieves high efficiency and stable catalytic activity, with a catalytic yield of 97%. The catalyst can be recycled multiple times, and the product has high purity, few impurities, and is environmentally friendly.
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Figure CN121895376A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of chemical synthesis, specifically relating to a silver-based alloy nanocluster and its application in the photocatalytic selective oxidative coupling reaction of benzylamine. Background Technology
[0002] Imines are key structural units in antitumor drugs, antibacterial drugs, Alzheimer's disease treatments, as well as fine chemicals such as dyes and fragrances, and nitrogen-containing functional materials. Currently, their synthesis mainly relies on the hydrogenation of nitro compounds or the dehydration condensation of amines with carbonyl compounds. These methods typically require the use of highly reactive aldehydes, Lewis acids, strong oxidants, or precious metal catalysts such as palladium and platinum, resulting in harsh reaction conditions (high temperature and high pressure), numerous byproducts, low atom economy, and problems such as difficult catalyst recovery and environmental pollution.
[0003] In recent years, organic synthesis using photocatalysts under photo-driven catalytic cycles has attracted great interest due to its simplicity and environmental friendliness. Yang's research group described three novel silver nanoclusters linked by the multidentate chelate nitrogen-containing ligand 3,5-bis(2-pyridyl)pyrazole (Hbpypz), namely [Ag... 27 (bpypz) 14 ]3(Ag 27 ), [Ag 62 (bpypz) 18 ]6(Ag 62 ) and [Ag 91 (bpypz) 24 ]5(Ag 91 In the photocatalytic selective oxidative coupling reaction of benzylamine, after 0.5 hours of reaction, Ag... 27 It exhibited high catalytic activity with a yield of 94%; Ag 91 The yield was moderate, at 43%; Ag 91 The three nanoclusters exhibited the lowest catalytic activity and a yield of 24%, but because they are homogeneous catalysts, they cannot be recycled (10.1021 / acsnano.4c16160). Therefore, developing efficient, stable, and recyclable photocatalysts for organic synthesis is crucial for transforming traditional thermoorganic chemistry into green and sustainable organic chemistry. Summary of the Invention
[0004] To address the problems existing in the prior art, this invention provides a silver-based alloy nanoclusters and their application in the photocatalytic selective oxidative coupling reaction of benzylamine. The silver-based alloy nanoclusters prepared in this invention are simple and exhibit excellent stability. The silver-based alloy nanocluster catalyst demonstrates high catalytic activity in the photocatalytic selective oxidative coupling reaction of benzylamine, with a catalytic yield of 97% for the supported silver-based alloy nanocluster catalyst. The catalytic conditions are mild, the catalyst is easily recovered and reused, and multiple catalytic cycles can be performed. It is also suitable for the photocatalytic selective oxidative coupling reaction of various benzylamine substrates, producing imine products with high purity and low impurity content.
[0005] The silver-based alloy nanoclusters of this invention have the molecular formula [Pt2Ag]. 23 (PPh3) 10 Cl7], where PPh3 is triphenylphosphine.
[0006] The method for preparing silver-based alloy nanoclusters of the present invention includes the following steps:
[0007] S1: Silver nitrate was dissolved in methanol under ultrasound, and then a platinum source was added to the solution. After stirring at room temperature for 15 minutes, dichloromethane solvent containing PPh3 was added to obtain a white metal-ClPPh3 complex. Then a reducing agent was added to the system, and after stirring in the dark for 12 hours, the reaction solution turned orange.
[0008] S2: The orange solution obtained in S1 was subjected to rotary evaporation. The resulting solid was washed with ethanol to remove impurities, then dried after rotary evaporation to obtain orange [Pt2Ag]. 23 (PPh3) 10 Cl7] nanoclusters, abbreviated as Pt2Ag 23 .
[0009] In S1, the platinum source is chloroplatinic acid; the reducing agent is NaBH4.
[0010] Furthermore, the molar ratio of silver nitrate, platinum source, triphenylphosphine, and reducing agent is 10:1:70:48.
[0011] The present invention relates to the application of silver-based alloy nanoclusters in the photocatalytic selective oxidative coupling reaction of benzylamine.
[0012] Specifically, the silver-based alloy nanoclusters were loaded onto titanium dioxide as a support to obtain the supported silver-based alloy nanocluster catalyst Pt2Ag. 23 / TiO2, using this supported catalyst to catalyze the photocatalytic selective oxidative coupling reaction of benzylamine.
[0013] The loading process includes the following steps: adding 1 mg of orange Pt2Ag 23The clusters were added to 10 mL of dichloromethane solvent, followed by 99 mg of titanium dioxide. The mixture was stirred at room temperature for 30 minutes, and the orange solid was collected by centrifugation. After vacuum filtration and drying, the supported silver-based alloy nanocluster catalyst Pt₂Ag was obtained. 23 / TiO2, with a loading of 1 wt%.
[0014] The synthetic route for the photocatalytic selective oxidative coupling reaction of benzylamine is shown below:
[0015] .
[0016] R is selected from hydrogen, alkyl, hydroxyl or halogen.
[0017] Furthermore, R is selected from hydrogen, methyl, tert-butyl, hydroxyl, bromine, or chlorine.
[0018] The light source used for the photocatalytic reaction is a 365 nm LED lamp.
[0019] The beneficial effects of this invention are reflected in:
[0020] 1. Compared with cobalt, zinc and nickel complex catalysts, the silver-based alloy nanocluster catalyst of this invention is basically non-toxic. As a highly efficient heterogeneous catalyst, it has a high specific surface area and excellent selectivity, and will not be over-oxidized into benzyl nitrile.
[0021] 2. The silver-based alloy nanocluster catalyst of the present invention exhibits high catalytic activity in the photocatalytic selective oxidative coupling reaction of benzylamine. The catalytic yield of the unsupported silver-based alloy nanocluster catalyst is less than 10%, while the catalytic yield of the supported silver-based alloy nanocluster catalyst reaches 97%.
[0022] 3. The experimental process of this invention is simple and easy to carry out, and the cost is low, making it highly applicable.
[0023] 4. The catalytic conditions of this invention are mild, the catalyst can be recycled, and it can carry out more than 5 photocatalytic reactions while maintaining an excellent yield of more than 90%, which has high economic and environmental benefits. Attached Figure Description
[0024] Figure 1 This is the ultraviolet absorption spectrum of the silver-based alloy nanoclusters of this invention.
[0025] Figure 2 This is a transmission electron microscope (TEM) image of the supported silver-based alloy nanocluster catalyst of this invention.
[0026] Figure 3 This is a single-crystal structure diagram of the silver-based alloy nanoclusters of the present invention.
[0027] Figure 4The yield diagram shows the photocatalytic selective oxidative coupling reactions of different benzylamine substrates to prepare corresponding imine products using the silver-based alloy nanocluster catalyst prepared in this invention. Detailed Implementation
[0028] The technical solution of the present invention will be further explained and illustrated below with reference to specific embodiments.
[0029] Example 1: Silver-based alloy nanoclusters Pt2Ag 23 Preparation
[0030] S1: 20 mg of silver nitrate was dissolved in 10 mL of methanol under sonication, and then 4.4 mg of chloroplatinic acid was added to the solution. After stirring at room temperature for 15 minutes, 15 mL of dichloromethane solution containing 200 mg of PPh3 was added to obtain a white metal-ClPPh3 complex. Subsequently, 1 mL of methanol solution of NaBH4 (20 mg) was added dropwise to the system, and after stirring in the dark for 12 hours, the reaction solution turned orange.
[0031] S2: The orange solution obtained in S1 was subjected to rotary evaporation. The resulting solid was washed with ethanol to remove impurities, then dried after rotary evaporation to obtain orange [Pt2Ag]. 23 (PPh3) 10 Cl7] nanoclusters.
[0032] Example 2: Supported silver-based alloy nanocluster catalyst Pt2Ag 23 Preparation of TiO2
[0033] 1 mg of orange Pt2Ag 23 The clusters were added to 10 mL of dichloromethane solvent, followed by 99 mg of titanium dioxide. The mixture was stirred at room temperature for 30 minutes, and the orange solid was collected by centrifugation. After vacuum filtration and drying, the supported silver-based alloy nanocluster catalyst Pt₂Ag was obtained. 23 / TiO2, with a loading of 1 wt%.
[0034] Example 3: Unsupported silver-based alloy nanocluster catalyst Pt2Ag 23 Catalytic synthesis of N-benzylbenzylamine
[0035] Select a 10 mL Schlenk tube, add 3 mL of acetonitrile solvent, followed by benzylamine (0.2 mmol, 22 µL) and 1 mg Pt2Ag. 23The catalyst was sealed in a Schlenk tube with a rubber stopper and a vacuum was applied. An oxygen balloon was attached, and the reaction was stirred under an LED lamp at a wavelength of 365 nm for 0.5 hours. At the end of the reaction, the balloon was removed, and 23 µL of n-dodecane was added as an internal standard (the equimolar peak area ratio of the product N-benzylbenzylamine and the internal standard dodecane was 0.95). The catalyst was removed by centrifugation to obtain the organic matter. The yield was analyzed by gas chromatography (GC), and the yield was 10%.
[0036] Example 4: Pt2Ag 23 / TiO2-catalyzed synthesis of N-benzylbenzylamine
[0037] Select a 10 mL Schlenk tube, add 3 mL of acetonitrile solvent, followed by benzylamine (0.2 mmol, 22 µL) and 30 mg Pt2Ag. 23 / TiO2 (1wt%) catalyst, Schlenk tube sealed with rubber stopper and vacuumed, and oxygen balloon attached, stirred under LED light at 365 nm wavelength for 0.5 h; at the end of the reaction, the balloon was removed and 23 µL of n-dodecane was added as internal standard (equimolar peak area ratio of N-benzylbenzylamine and internal standard dodecane was 0.95), the catalyst was removed by centrifugation to obtain organic matter, and the yield was analyzed by gas chromatography (GC), the yield was 97%.
[0038] Example 5: Pt2Ag 23 / TiO2-catalyzed synthesis of N-benzylbenzylamine (chloroform solvent)
[0039] Select a 10 mL Schlenk tube, add 3 mL of chloroform solvent, followed by benzylamine (0.2 mmol, 22 µL) and 30 mg Pt₂Ag. 23 / TiO2 (1wt%) catalyst, Schlenk tube sealed with rubber stopper and vacuumed, and oxygen balloon attached, stirred under LED light at 365 nm wavelength for 0.5 h; at the end of the reaction, the balloon was removed and 23 µL of n-dodecane was added as internal standard (equimolar peak area ratio of N-benzylbenzylamine and internal standard dodecane was 0.95), the catalyst was removed by centrifugation to obtain organic matter, and the yield was analyzed by gas chromatography (GC), the yield was 54%.
[0040] Example 6: Pt2Ag 23 / TiO2-catalyzed synthesis of N-benzylbenzylamine (methanol solvent)
[0041] Select a 10 mL Schlenk tube, add 3 mL of methanol solvent, followed by benzylamine (0.2 mmol, 22 µL) and 30 mg Pt2Ag. 23 / TiO2 (1wt%) catalyst, a Schlenk tube was sealed with a rubber stopper and evacuated, and an oxygen balloon was attached. The reaction was stirred under an LED lamp at a wavelength of 365 nm for 0.5 hours. At the end of the reaction, the balloon was removed and 23 µL of n-dodecane was added as an internal standard (the gas phase peak area ratio of the equimolar product N-benzylbenzylamine and the internal standard dodecane was 0.95). The catalyst was removed by centrifugation to obtain the organic matter. The yield was analyzed by gas chromatography (GC) and the yield was 50%.
[0042] Example 7: Cyclic Experiment: Recovery of Pt₂Ag 23 / TiO2 catalyst for the synthesis of N-benzylbenzylamine
[0043] 1. After completing the fresh experiment to synthesize N-benzylbenzylamine, centrifuged the Pt2Ag... 23 TiO2 was washed three times with dichloromethane and dried under vacuum at 60 °C for 8 hours. A 10 mL Schlenk tube was selected, and 3 mL of acetonitrile and benzylamine (0.2 mmol, 22 µL) were added. Recovered Pt2Ag was used. 23 TiO2 was used as a catalyst. The Schlenk tube was sealed with a rubber stopper and a vacuum was applied. An oxygen balloon was attached, and the reaction was stirred under a 365 nm LED lamp for 0.5 hours. At the end of the reaction, the balloon was removed, and 23 µL of n-dodecane was added as an internal standard (the equimolar peak area ratio of the product N-benzylbenzylamine and the internal standard dodecane was 0.95). The catalyst was removed by centrifugation to obtain the organic matter. The yield was analyzed by gas chromatography (GC), and the yield was 96%.
[0044] 2. The recovered catalyst was repeated under the above reaction conditions until the 5th cycle. After the catalyst was removed by centrifugation (10,000 rpm), the target product N-benzylbenzylamine was obtained. The yield was determined to be 90% by gas chromatography (GC).
[0045] Example 8: Pt2Ag 23 / TiO2-catalyzed synthesis of N-(4-methylbenzyl)-1-(p-methylphenyl)methyleneimine
[0046] Select a 10 mL Schlenk tube, add 3 mL of acetonitrile solvent, followed by 0.2 mmol (26 µL) of 4-methylbenzylamine and 30 mg of Pt2Ag. 23 / TiO2 (1wt%) catalyst, Schlenk tube sealed with rubber stopper and vacuumed, and oxygen balloon attached, stirred under LED light at 365 nm wavelength for 0.5 hours; at the end of the reaction, the balloon was removed and 23 µL of n-dodecane was added as internal standard (equimolar peak area ratio of N-benzylbenzylamine and internal standard dodecane was 0.95), the catalyst was removed by centrifugation to obtain organic matter, and the yield was analyzed by gas chromatography (GC), and the yield was 92%.
[0047] Example 9: Pt2Ag 23 / TiO2-catalyzed synthesis of N-(4-(tert-butyl)benzyl)-1-(4-(tert-butyl)phenyl)methyleneimine
[0048] Select a 10 mL Schlenk tube, add 3 mL of acetonitrile solvent, followed by 0.2 mmol (35 µL) of 4-tert-butylbenzylamine and 30 mg of Pt2Ag. 23 / TiO2 (1wt%) catalyst, a Schlenk tube was sealed with a rubber stopper and evacuated, and an oxygen balloon was attached. The reaction was stirred under an LED lamp at a wavelength of 365 nm for 0.5 hours. At the end of the reaction, the balloon was removed and 23 µL of n-dodecane was added as an internal standard (the equimolar peak area ratio of the product N-benzylbenzylamine and the internal standard dodecane was 0.95). The catalyst was removed by centrifugation to obtain the organic matter. The yield was analyzed by gas chromatography (GC) and the yield was 89%.
[0049] Example 10: Pt2Ag 23 / TiO2-catalyzed synthesis of 2-((2-hydroxybenzyl)amino)phenol
[0050] Select a 10 mL Schlenk tube, add 3 mL of acetonitrile solvent, followed by o-hydroxybenzylamine (0.2 mmol, 22 µL) and 30 mg Pt2Ag. 23 / TiO2 (1wt%) catalyst, Schlenk tube sealed with rubber stopper and vacuumed, and oxygen balloon attached, stirred under LED light at 365 nm wavelength for 0.5 hours; at the end of the reaction, the balloon was removed and 23 µL of n-dodecane was added as internal standard (equimolar peak area ratio of N-benzylbenzylamine and internal standard dodecane was 0.95), the catalyst was removed by centrifugation to obtain organic matter, and the yield was analyzed by gas chromatography (GC), and the yield was 92%.
[0051] Example 11: Pt2Ag 23 / TiO2-catalyzed synthesis of N-(4-bromobenzyl)-1-(4-bromophenyl)methylimine
[0052] Select a 10 mL Schlenk tube, add 3 mL of acetonitrile solvent, followed by 0.2 mmol (24 µL) of 4-bromobenzylamine and 30 mg of Pt₂Ag. 23 / TiO2 (1wt%) catalyst, Schlenk tube sealed with rubber stopper and vacuumed, and oxygen balloon attached, stirred under LED light at 365 nm wavelength for 0.5 h; at the end of the reaction, the balloon was removed and 23 µL of n-dodecane was added as internal standard (equimolar peak area ratio of N-benzylbenzylamine and internal standard dodecane was 0.95), the catalyst was removed by centrifugation to obtain organic matter, and the yield was analyzed by gas chromatography (GC), and the yield was 90%.
[0053] Example 12: Pt2Ag 23 / TiO2-catalyzed synthesis of N-(4-chlorobenzyl)-1-(4-chlorophenyl)methylimine
[0054] Select a 10 mL Schlenk tube, add 3 mL of acetonitrile solvent, followed by 0.2 mmol (24 µL) of 4-chlorobenzylamine and 30 mg of Pt2Ag. 23 / TiO2 (1wt%) catalyst, Schlenk tube sealed with rubber stopper and vacuumed, and oxygen balloon attached, stirred under LED light at 365 nm wavelength for 0.5 h; at the end of the reaction, the balloon was removed and 23 µL of n-dodecane was added as internal standard (equimolar peak area ratio of N-benzylbenzylamine and internal standard dodecane was 0.95), the catalyst was removed by centrifugation to obtain organic matter, and the yield was analyzed by gas chromatography (GC), the yield was 95%.
Claims
1. A silver-based alloy nanocluster, characterized in that: The molecular formula of the silver-based alloy nanoclusters is [Pt2Ag]. 23 (PPh3) 10 Cl7], where PPh3 is triphenylphosphine.
2. The method for preparing the silver-based alloy nanoclusters according to claim 1, characterized in that... Includes the following steps: S1: Silver nitrate was dissolved in methanol under ultrasound, and then a platinum source was added to the solution. The mixture was stirred and dispersed evenly at room temperature. Then, a dichloromethane solution containing PPh3 was added to obtain a white metal-ClPPh3 complex. Next, a reducing agent was added to the system, and the reaction was stirred in the dark until the reaction solution turned orange. S2: The orange solution obtained in S1 was subjected to rotary evaporation. The resulting solid was washed with ethanol to remove impurities, then dried after rotary evaporation to obtain orange [Pt2Ag]. 23 (PPh3) 10 Cl7] nanoclusters.
3. The preparation method according to claim 2, characterized in that: In S1, the platinum source is chloroplatinic acid; the reducing agent is NaBH4.
4. The preparation method according to claim 2, characterized in that... In S1, the molar ratio of silver nitrate, platinum source, triphenylphosphine, and reducing agent is 10:1:70:
48.
5. The application of the silver-based alloy nanoclusters according to claim 1 in the photocatalytic selective oxidative coupling reaction of benzylamine.
6. The application according to claim 5, characterized in that: Using titanium dioxide as a support, the silver-based alloy nanoclusters were loaded onto the support to obtain a supported silver-based alloy nanocluster catalyst, abbreviated as Pt2Ag. 23 / TiO2, with Pt2Ag 23 / TiO2-catalyzed photocatalytic selective oxidative coupling reaction of benzylamine.
7. The application according to claim 6, characterized in that: The photocatalytic selective oxidative coupling reaction includes the following steps: Using acetonitrile as solvent and oxygen as oxidant, a supported silver-based alloy nanocluster catalyst Pt₂Ag was developed. 23 In the presence of TiO2, photocatalytic selective oxidative coupling of benzylamine to prepare imine products at room temperature; The synthesis route is shown below: ； R is selected from hydrogen, alkyl, hydroxyl or halogen.
8. The application according to claim 7, characterized in that: The light source used for the photocatalytic reaction is a 365 nm LED lamp.
9. The application according to claim 6, characterized in that: The loading process includes the following steps: adding 1 mg of orange Pt2Ag 23 The clusters were added to 10 mL of dichloromethane solvent, followed by 99 mg of titanium dioxide. The mixture was stirred at room temperature for 30 minutes, and the orange solid was collected by centrifugation. After vacuum filtration and drying, the supported silver-based alloy nanocluster catalyst Pt₂Ag was obtained. 23 / TiO2, with a loading of 1 wt%.