Cobalt cluster synthesis and electrolysis application under high current density
By preparing cobalt clusters Co7-I and applying them to the electrocatalytic reaction of allenes with aldehydes, the problems of unstable synthesis of cobalt clusters and low yield at high current densities in existing technologies have been solved, achieving efficient preparation of allenyl alcohols and generation of clean fuels.
Patent Information
- Application Number
- CN202511575859.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-31
- Publication Date
- 2026-02-27
AI Technical Summary
Existing technologies make it difficult to accurately synthesize stable cobalt metallic clusters, resulting in limited research on their electrocatalysis, especially the low yield and easy isomerization of allene C(sp2)-H bond functionalization reaction under high current density.
Cobalt clusters Co7-I were prepared using cobalt salts, triphenylphosphine, 2,6-dimethylthiophenol, and sodium borohydride under specific reaction conditions. The cobalt clusters were then applied to the electrocatalytic reaction of allenes with aldehydes, using aprotic polar solvents and electrolytes for electrocatalysis.
Achieving high yields of allenyl alcohols at low current densities while maintaining a 60% yield at high current densities, while simultaneously producing usable clean fuel hydrogen.
Smart Images
Figure CN121574153A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of metal cluster, in particular to a cobalt cluster synthesis and electrolysis application under high current density. BACKGROUND
[0002] Metal cluster is a polynuclear aggregate composed of multiple metal atoms, with a certain atomic composition and structure. Due to its diverse structure, controllable composition, interesting physical and chemical properties, and potential application value, it has attracted great attention from researchers. It has the advantages of high purity, accurate structure, clear surface environment, etc., and is considered as a new type of electrocatalyst, which is widely used in hydrogen evolution reaction (HER), electrochemical ammonia synthesis reaction (ESA), electrochemical CO2 reduction reaction (CO2RR), electrocatalytic oxygen evolution reaction (OER), electrocatalytic oxygen reduction reaction (ORR) and the like.
[0003] So far, many controllable metal cluster preparation methods have been developed, such as direct synthesis method, ligand exchange method, size focusing method, inter-cluster reaction method, etc. Although a series of effective synthesis methods have been developed to prepare metal clusters with clear size, structure and composition, the rational design and successful preparation of atomically precise cobalt clusters still face challenges.
[0004] Due to the difficulty in successfully synthesizing stable structures in the range of a few cobalt atoms, it is difficult to accurately synthesize metal cobalt clusters, which also leads to limited electrocatalytic research on them. SUMMARY
[0005] Based on the technical problems existing in the background art, the present application proposes a cobalt cluster synthesis and electrolysis application under high current density, which successfully prepares cobalt cluster Co7-I, which has good electrocatalytic performance; can electrocatalyze the reaction of allenes with aldehyde substances to obtain allene-based alcohols; when using the cobalt cluster Co7-I described in the present application, not only can high-yield allene-based alcohols be prepared under low current density, but also allene-based alcohols can be quickly catalyzed to prepare under high current density ≥20 mA / cm 2 2, and the yield is as high as 60%. 2
[0006] The present application proposes a cobalt cluster, the molecular general formula of which is Co7S6(PPh3)3(NO)4, wherein PPh3 is a triphenylphosphine ligand, and NO is a nitroso ligand.
[0007] The above-mentioned cobalt cluster is denoted as Co7-I.
[0008] The application further provides a preparation method of the cobalt cluster, comprising the following steps: uniformly mixing a cobalt salt, triphenylphosphine and an organic solvent, performing a first reaction, adding 2,6-dimethylbenzenethiol and a reducing agent, and performing a second reaction to obtain the cobalt cluster.
[0009] Preferably, after the second reaction, column chromatography or thin layer chromatography purification is performed to obtain the cobalt cluster.
[0010] Preferably, the eluent for the column chromatography or thin layer chromatography purification is a mixture of dichloromethane and petroleum ether in equal volume.
[0011] In the column chromatography, the elution speed is 9-11 mL / min; and after the elution is started, the eluent collected within 0-15 min is obtained as the cobalt cluster Co7-I.
[0012] Preferably, an ice water solution of the reducing agent is added to perform the reaction.
[0013] The ice water solution has a temperature of-50 to 0℃.
[0014] Preferably, the concentration of the ice water solution of the reducing agent is 0.3-4 mmol / ml.
[0015] Preferably, the reducing agent is sodium borohydride.
[0016] Preferably, the cobalt salt is at least one of cobalt nitrate hexahydrate, cobalt nitrate, cobalt chloride and cobalt perchlorate.
[0017] Preferably, the organic solvent is tetrahydrofuran.
[0018] Preferably, the molar ratio of cobalt element to triphenylphosphine is 1:1-2.3.
[0019] Preferably, the molar ratio of cobalt element to 2,6-dimethylbenzenethiol is 1:1.3-6.
[0020] Preferably, the molar ratio of cobalt element to reducing agent is 1:2.5-19.5.
[0021] Preferably, the first reaction is performed for 20-40 min at room temperature.
[0022] Preferably, the second reaction is performed for 2.5-3.5 h at 40-80℃.
[0023] The application further provides application of the cobalt cluster and the cobalt cluster prepared by the method in a catalyst.
[0024] Preferably, the application is in an electrocatalyst.
[0025] The application further provides application of the cobalt cluster and the cobalt cluster prepared by the method in catalyzing C(sp 2 )-H bond functionalization of a diene.
[0026] Preferably, the application is used in the electrocatalytic C(sp 2 )-H bond functionalization.
[0027] Preferably, the application is used in the electrocatalytic C(sp 2 )-H bond functionalization.
[0028] Preferably, the application is used in the electrocatalytic C(sp 2 )-H bond functionalization.
[0029] Preferably, the application is used in the electrocatalytic C(sp 2 )-H bond functionalization.
[0030] Preferably, the application is used in the electrocatalytic C(sp 2 )-H bond functionalization.
[0031] Preferably, the application is used in the electrocatalytic C(sp 2 )-H bond functionalization.
[0032] Preferably, the 1,3-disubstituted allene has a structure as shown in formula (I): Formula (I); wherein R1 and R2 are independently one of alkyl, cycloalkyl, aryl, substituted aryl; the substituent in the substituted aryl is one or more of alkyl, alkenyl, alkynyl, hydroxyl, thiol, amino, ester, phenyl, alkoxy, alkylthio, unsaturated alkoxy, unsaturated alkylthio, halogen, halogenated alkyl, halogenated alkoxy, halogenated alkylthio, halogenated unsaturated alkoxy, halogenated unsaturated alkylthio, hydroxyalkyl, hydroxyaryl, cycloalkyl, N-doped cycloalkyl, S-doped cycloalkyl, O-doped cycloalkyl, unsaturated cycloalkyl, N-doped unsaturated cycloalkyl, S-doped unsaturated cycloalkyl, O-doped unsaturated cycloalkyl.
[0033] Preferably, the 1,3-disubstituted allene includes one of: , , , wherein X is halogen.
[0034] Preferably, the functional group in the functionalization is ; wherein R3 is one of aryl, substituted aryl, cycloalkyl, S-doped unsaturated cycloalkyl. The substituent in the substituted aryl group is: alkyl, alkenyl, alkynyl, amino, ester, phenyl, alkoxy, halogen, haloalkyl, haloalkoxy, haloalkylthio, halo-unsaturated alkoxy, halo-unsaturated alkylthio, hydroxyalkyl, hydroxyaryl, cycloalkyl.
[0035] The substituted aryl group in the present application refers to an aryl group with a substituent. The above-mentioned alkyl group is preferably an alkyl group with 1-8 carbon atoms.
[0036] Preferably, Comprise: , , , , One of the above.
[0037] Preferably, the electrocatalysis is carried out in the presence of an electrolyte.
[0038] Preferably, the electrolyte is at least one of tetraalkylammonium tetrafluoroborate, tetrabutylammonium perchlorate, tetrabutylammonium high phosphate.
[0039] The alkyl group in the above-mentioned tetraalkylammonium tetrafluoroborate can be an alkyl group with 1-8 carbon atoms, and can also be a benzyl group; preferably, it is tetrabutylammonium tetrafluoroborate.
[0040] Preferably, the electrocatalysis is carried out in aprotic polar solvent. 2 )-H bond functionalization.
[0041] Preferably, the aprotic polar solvent comprises at least one of N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, N-methyl pyrrolidone, tetrahydrofuran, 1,3-dimethyl-tetrahydro-2-pyrimidinone, hexamethylphosphoric triamide.
[0042] Preferably, the molar ratio of the aldehyde substance and the diene is 1:1.2-2.2.
[0043] Preferably, the molar ratio of the aldehyde substance and the cobalt cluster is 1:0.00005-1.
[0044] Preferably, the temperature of the electrocatalysis is -50 to 60℃.
[0045] Preferably, the current density of the electrocatalysis is 0.01-5000 mA / cm 2 .
[0046] The concentration of the above-mentioned electrolyte is 0.09-0.1 mol / L.
[0047] The time of the above-mentioned electrocatalysis is 0.5-4h.
[0048] The anode of the aforementioned electrocatalysis can be graphite felt (GF), carbon rod, platinum, glassy carbon, mesh glassy carbon electrode (RVC), zinc, etc., and the cathode can be stainless steel (SS), nickel, copper, platinum, iron, zinc, cobalt, gold, silver, carbon rod, glassy carbon, mesh glassy carbon electrode (RVC), etc.
[0049] The above electrocatalytic allene C(sp) 2 The )-H bond functionalization reaction specifically includes the following steps: allene, aldehyde, cobalt cluster, electrolyte, and N,N-dimethylformamide are mixed, inserted into the cathode and anode plates, and electrocatalytic reaction is carried out by passing an electric current to obtain allenyl alcohol.
[0050] The hydrogen produced during the electrocatalytic process described above can be collected and used as a clean fuel.
[0051] After the above electrocatalytic reaction, allenyl alcohol is obtained by purification. The specific purification steps include: after the electrocatalytic reaction is completed, water and ethyl acetate are added for extraction, the organic phase is concentrated, column purification is performed, the eluent is collected, the solvent is removed, and allenyl alcohol is obtained.
[0052] The above column purification can be silica gel column purification; the eluent for column purification can be a mixture of petroleum ether and ethyl acetate in a volume ratio of 10-20:1.
[0053] Beneficial effects
[0054] 1. This invention successfully prepared cobalt clusters Co7-I by selecting appropriate ligands and appropriate process parameters.
[0055] 2. The cobalt cluster Co7-I exhibits excellent electrocatalytic performance, enabling it to electrocatalyze the reaction of allenes with aldehydes, thereby increasing the C(sp) content of the allene. 2 Functionalization of the )-H bond yields allenyl alcohols.
[0056] 3. Allene C(sp) 2 Functionalization of the )-H bond presents challenges such as high reaction inertia, easy isomerization, and generation of alkyne-containing byproducts. Existing electrocatalysts are used in the electrocatalytic formation of allene C(sp...) 2 When preparing allenyl alcohols by functionalizing )-H bonds, only small currents can be used for electrocatalysis, resulting in long catalytic times and low yields. Using large currents further reduces the yield to only 20%. However, using the cobalt cluster Co7-I described in this invention not only yields allenyl alcohols in high yields (up to 72%) at low current densities, but also at ≥20 mA / cm². 2 Allenyl alcohols can be rapidly catalyzed under high current density conditions with a yield of up to 60%; in addition, the electrocatalytic reaction can also produce hydrogen, which can be used as a clean fuel. Attached Figure Description
[0057] Figure 1 A single crystal structure diagram of the cobalt cluster Co7-I crystal.
[0058] Figure 2 An ultraviolet spectrum diagram of the cobalt cluster Co7-I crystal.
[0059] Figure 3 A mass spectrum diagram of the cobalt cluster Co7-I crystal.
[0060] Figure 4 A H NMR spectrum of the target product 3a in Example 3. 1 H NMR spectrum.
[0061] Figure 5 A C NMR spectrum of the target product 3a in Example 3. 13 C NMR spectrum. DETAILED DESCRIPTION
[0062] Hereinafter, the technical solutions of the present application are described in detail through specific examples.
[0063] Example 1
[0064] A preparation method of a cobalt cluster, comprising the following steps: Co (NO3) 2·6H2O (65 mg, 0.22 mmol) and triphenylphosphine (130 mg, 0.50 mmol) were dissolved in 10 mL of tetrahydrofuran, stirred in a flask with a magnet at room temperature for 30 min, then 2,6-dimethylbenzenethiol (160 mg, 1.16 mmol) was added, 10 min later, freshly prepared sodium borohydride ice water solution (160 mg, 4.23 mmol of sodium borohydride was dissolved in 5 mL of ice water at -10℃) was added at one time; then stirred at 60℃ for 3h, the reaction solution was dried, then purified by thin layer chromatography plate (its eluent was a mixture of equal volumes of dichloromethane and petroleum ether), 25 mg of cobalt cluster was obtained, recorded as Co7-I, the yield based on Co atom was 52%.
[0065] The band of Co7-I was scraped from the thin layer chromatography plate and dissolved in a mixture of dichloromethane and n-heptane in a volume ratio of 1:1, and the cobalt cluster Co7-I crystal was obtained by slow evaporation.
[0066] The cobalt cluster Co7-I crystal prepared above was taken for detection, and the results are shown in Figures 1-3 .
[0067] Figure 1 A single crystal structure diagram of the cobalt cluster Co7-I crystal.
[0068] Figure 2 An ultraviolet spectrum diagram of the cobalt cluster Co7-I crystal.
[0069] Figure 3 This is the mass spectrum of the Co7-I crystal cluster.
[0070] Depend on Figures 1-3 It can be seen that the cobalt cluster Co7-I is composed of triphenylphosphine ligand, nitroso ligand, S, and Co, and its general molecular formula is Co7S6(PPh3)3(NO)4.
[0071] Example 2
[0072] Scale-up production of cobalt clusters A method for preparing cobalt clusters includes the following steps: Add Co(NO3)2·6H2O (4.51 g, 15.5 mmol) and triphenylphosphine (5.2 g, 19.8 mmol) to a 1000 mL round-bottom flask, dissolve in 300 mL of tetrahydrofuran, and stir continuously at room temperature for 30 min. Then add 2,6-dimethylthiophenol (3.52 g, 25.3 mmol). After 2 min, add freshly prepared ice-water solution of sodium borohydride (1.56 g, 41.24 mmol sodium borohydride dissolved in 20 mL of water). The reaction mixture was stirred at 60°C for 3 hours in 0 mL of ice water at 0°C. The reaction solution was dried, washed with water, and then purified by flash column chromatography (using an equal volume mixture of dichloromethane and n-hexane as the eluent) at a rate of 10 mL / min. After the start of elution, the eluent was collected within 0-15 min, and the solvent was removed to obtain 1.23 g of cobalt cluster Co7-I (yield based on Co atoms was 37%).
[0073] Example 3
[0074] An electrocatalytic allene C(sp) 2 The method for functionalizing H-bonds includes the following steps: A magnetic stirrer, a stainless steel sheet, and a graphite felt are installed in the reaction flask, with the stainless steel sheet serving as the cathode and the graphite felt as the anode. Allene 1a (1.0 mmol), aldehyde 2a (0.5 mmol), cobalt cluster Co7-I (15 mg, 0.01 mmol), and tetrabutylammonium tetrafluoroborate (329 mg, 1.0 mmol) were added to 10 mL of N,N-dimethylformamide. The mixture was then heated at 40 °C, and the current density was adjusted to... J = 100 mA·cm -2, stirring for 36 min; then the reaction solution was poured into 100 mL of water, extracted with ethyl acetate for 3 times, each time with 40 mL of ethyl acetate, the combined organic phase was dried with anhydrous sodium sulfate, then rotary evaporated to remove ethyl acetate, and then purified by column chromatography (its eluent was a mixture of petroleum ether and ethyl acetate in a volume ratio of 10:1), to obtain 96 mg of the target product 3a, with a yield of 69%.
[0075] The structural formula of 1a, 2a, 3a in the above example 3 is as follows: 、 、 .
[0076] Figure 4 The H NMR spectrum of the target product 3a in example 3. 1 H NMR spectrum.
[0077] Figure 5 The C NMR spectrum of the target product 3a in example 3. 13 C NMR spectrum.
[0078] 1 H NMR (400 MHz, CDCl3): δ 7.42 (m, 2H), 7.31 (m, 7H), 7.21 (m, 1H),6.47 (q, J = 4 Hz, 0.4H) (isomer), 6.42 (q, J = 2.7 Hz, 0.4H) (isomer), 5.24(s, 0.4H) (isomer), 5.14 (s, 0.4H) (isomer), 2.36 (br, 1H), 1.97 (m, 2H),1.40 (m, 2H), 1.27 (m, 2H), 0.81 (t, J = 6.0 Hz, 3H). 13 C NMR (101 MHz, CDCl3): δ 200.7, 200.2, 142.13, 142.07, 134.8,134.7, 128.6, 128.38, 128.35, 127.83, 127.80, 127.10, 127.07, 126.70, 126.65,113.8, 113.4, 99.9, 99.3, 74.8, 74.7, 29.9, 29.7, 28.5, 28.2, 22.43, 22.40,13.8. Example 4 Electrocatalytic alkyne C(sp2 Scale-up production of )-H bond functionalization An electrocatalytic allene C(sp) 2 The method for functionalizing H-bonds includes the following steps: A magnetic stirrer, a stainless steel electrode, and a graphite felt electrode are installed in the reaction flask. The stainless steel electrode serves as the cathode, and the graphite felt electrode serves as the anode. Add allene 1a (40 mmol), aldehyde 2a (20 mmol), cobalt cluster Co7-I (300 mg, 0.2 mmol), tetrabutylammonium tetrafluoroborate (2.63 g, 8 mmol), and 80 mL of N,N-dimethylformamide to the reaction flask and mix well. Adjust the current density to [value missing] at 40 °C. J = 22 mA·cm -2 The reaction mixture was stirred and electrolyzed for 4 hours. Then, the reaction solution was poured into 400 mL of water and extracted three times with 100 mL of ethyl acetate each time. The combined organic phases were dried with anhydrous sodium sulfate, and then the ethyl acetate was removed by rotary evaporation. The product was then purified by silica gel column chromatography (the eluent was a mixture of petroleum ether and ethyl acetate in a volume ratio of 10:1) to obtain 3.4 g of the target product 3a, with a yield of 61%.
[0079] The structural formulas of 1a, 2a, and 3a in the above embodiment 4 are the same as those in embodiment 3.
[0080] Comparative Example 1 An electrocatalytic allene C(sp) 2 The method for functionalizing H-bonds includes the following steps: The cobalt cluster Co7-I (8 mg, 0.005 mmol) was replaced with an existing binuclear amino acid-cobalt complex (17 mg, 0.005 mmol), and the target product 3a was prepared according to the method in Example 3, with a yield of 22%.
[0081] Example 5
[0082] Different allenes and aldehydes with different structures were selected, and products were prepared according to the method in Example 3. The results are shown in Table 1.
[0083] Table 1
[0084] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.
Claims
1. A cobalt cluster, characterized in that, The general molecular formula of the cobalt cluster is Co7S6(PPh3)3(NO)4, where PPh3 is a triphenylphosphine ligand and NO is a nitroso ligand.
2. A method for preparing cobalt clusters as described in claim 1, characterized in that, The process includes the following steps: mixing cobalt salt, triphenylphosphine, and an organic solvent to carry out a first reaction, then adding 2,6-dimethylthiophenol and a reducing agent to carry out a second reaction to obtain cobalt clusters.
3. The method for preparing cobalt clusters according to claim 2, characterized in that, After the secondary reaction, the cobalt clusters are purified by column chromatography or thin-layer chromatography. Preferably, the eluent for column chromatography or thin-layer chromatography purification is a mixture of equal volumes of dichloromethane and petroleum ether. Preferably, an ice-water solution of reducing agent is added to carry out the reaction. Preferably, the concentration of the ice-water solution of reducing agent is 0.3-4 mmol / ml.
4. The method for preparing cobalt clusters according to claim 2 or 3, characterized in that, The reducing agent is sodium borohydride; preferably, the cobalt salt is at least one of cobalt nitrate hexahydrate, cobalt nitrate, cobalt chloride, and cobalt perchlorate; preferably, the organic solvent is tetrahydrofuran; preferably, the molar ratio of cobalt to triphenylphosphine is 1:1-2.3; preferably, the molar ratio of cobalt to 2,6-dimethylthiophenol is 1:1.3-6; preferably, the molar ratio of cobalt to reducing agent is 1:2.5-19.5; preferably, the reaction is carried out once at room temperature for 20-40 min; preferably, the reaction is carried out twice at 40-80℃ for 2.5-3.5 h.
5. The use of a cobalt cluster as described in claim 1, or a cobalt cluster prepared by the method described in any one of claims 2-4, as a catalyst; preferably, its use as an electrocatalyst.
6. A cobalt cluster as described in claim 1, or a cobalt cluster prepared by the method according to any one of claims 2-4, in the catalysis of allene C(sp...) 2 Applications in the functionalization of )-H bonds; preferably, in the electrocatalysis of allene C(sp) bonds. 2 Applications in the functionalization of )-H bonds; preferably, allene C(sp 2 The 1,2-propadiene group is retained even after the -H bond functionalization; preferably, the allene C(sp) group is present in the catalytic reaction of allenes with aldehydes. 2 Applications in the functionalization of )-H bonds; preferably, the reaction of allenes with aldehydes, allene C(sp 2 The product after functionalization of the )-H bond is an allenyl alcohol.
7. The application according to claim 6, characterized in that, The allene is a 1,3-disubstituted allene, a 1,1-disubstituted allene, or a trisubstituted allene; preferably, the structural formula of the 1,3-disubstituted allene is shown in formula (I): Formula (I); Among them, R1 and R2 are each independently one of alkyl, cycloalkyl, aryl, and substituted aryl; The substituents in the substituted aryl group are one or more of the following: alkyl, alkenyl, alkynyl, hydroxyl, mercapto, amino, ester, phenyl, alkoxy, alkylthio, unsaturated alkoxy, unsaturated alkylthio, halogen, haloalkyl, haloalkoxy, haloalkylthio, halounsaturated alkoxy, halounsaturated alkylthio, hydroxyalkyl, hydroxyaryl, cycloalkyl, N-doped cycloalkyl, S-doped cycloalkyl, O-doped cycloalkyl, unsaturated cycloalkyl, N-doped unsaturated cycloalkyl, S-doped unsaturated cycloalkyl, and O-doped unsaturated cycloalkyl. Preferably, the 1,3-disubstituted allene comprises: , , , One of them; where X is a halogen.
8. The application according to claim 6 or 7, characterized in that, Functionalized functional groups are ; R3 is one of aryl, substituted aryl, cycloalkyl, and S-doped unsaturated cycloalkyl. The substituents in substituted aryl groups are: alkyl, alkenyl, alkynyl, amino, ester, phenyl, alkoxy, halogen, haloalkyl, haloalkoxy, haloalkylthio, halounsaturated alkoxy, halounsaturated alkoxy, hydroxyalkyl, hydroxyaryl, and cycloalkyl. Preferably, include: , , , , One of them.
9. The application according to any one of claims 6-8, characterized in that, Electrocatalysis is performed in the presence of an electrolyte; preferably, the electrolyte is at least one selected from tetraalkyltetrafluoroborate amine, tetrabutylammonium perchlorate, and tetrabutylammonium perphosphate; preferably, allene C(sp) is carried out in an aprotic polar solvent. 2 )-H bond functionalization; preferably, the aprotic polar solvent includes at least one of: N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, N-methylpyrrolidone, tetrahydrofuran, 1,3-dimethyl-tetrahydro-2-pyrimidinone, and hexamethylphosphoric triamine.
10. The application according to any one of claims 6-9, characterized in that, The molar ratio of aldehydes to allenes is 1:1.2-2.2; preferably, the molar ratio of aldehydes to cobalt clusters is 1:0.00005-1; preferably, the electrocatalytic temperature is -50 to 60°C; preferably, the electrocatalytic current density is 0.01-5000 mA / cm². 2 .