A method for synthesizing 1,2-diketone compounds through surface coupling reaction

Abstract

The present invention discloses a method for synthesizing 1,2-diketone compounds through surface coupling reaction. The steps are as follows: performing cyclic argon etching-annealing treatment on the Au(111) surface to obtain a clean Au(111) surface; depositing 1,3,5-tris(p-formylphenyl)benzene molecules and iron atoms onto the clean Au(111) surface successively to obtain a metal substrate with 1,3,5-tris(p-formylphenyl)benzene molecules and iron atoms; annealing the metal substrate. The present invention synthesizes 1,2-diketone compounds through surface coupling reaction, and the yield reaches 87.4%. Compared with the coupling reaction in traditional solution, the yield of 1,2-diketone compounds is significantly improved, and no by-products are generated. The synthesized 1,2-diketone compounds, as an important raw material for organic synthesis, can be widely applied to the synthesis and preparation fields such as medicine, chemical engineering, and polymer materials.

Description

Technical Field

[0001] The present invention relates to a method for synthesizing 1,2-diketone compounds through surface coupling reaction, and belongs to the field of synthesis and preparation of organic compounds. Background Art

[0002] 1,2-diketone compounds are a class of compounds with two adjacent carbonyl groups, having high reactivity and being important raw materials for organic synthesis. 1,2-diketone compounds have pharmacological activities such as anti-cancer, anti-fungal and anti-bacterial, and have high bioavailability because the two adjacent carbonyl groups in them are easy to bind to proteins in the human body, and can be used as starting materials for drug synthesis; 1,2-diketone compounds can also be used in the synthesis of heterocyclic compounds and heterocyclic metal complexes, and are an important organic synthesis intermediate; 1,2-diketone compounds also show photochemical activity and can be used as photoinitiators to initiate polymerization reactions to synthesize polymers. In recent years, 1,2-diketone compounds have been widely used in the synthesis and preparation fields such as medicine, chemical industry and polymer materials.

[0003] So far, the synthesis of 1,2-diketone compounds has been carried out in solution, mainly including three methods: oxidation method, nucleophilic addition-elimination method and coupling method. Among them, the coupling method is a method of synthesizing 1,2-diketone compounds by using metal or metal salt as a catalyst to cause a coupling reaction between monocarbonyl compounds (such as aldehydes, acyl chlorides or carboxylic acids). However, in a solution environment, the preparation of 1,2-diketone compounds by the coupling method not only has cumbersome steps and involves dangerous reagents, but also generally has the disadvantage of low yield, and often generates by-products (such as carboxylic acid compounds).

[0004] In recent decades, with the development of nanoscience, people have begun to study chemical reactions occurring on two-dimensional surfaces, such as metal surfaces and metal oxide surfaces, and perform real-time in-situ characterization and analysis of the reaction process and molecular structure through scanning tunneling microscopy (STM) with atomic resolution and density functional theory (DFT) calculations. At present, many classic solution reactions and some new reactions that have not occurred in solution have been realized on the surface. Compared with traditional reactions occurring in solution, the preparation process of surface reactions is simple and controllable, avoiding the use of dangerous reagents, and due to the confinement effect of surface reactions, the reaction rate of raw material molecules is higher, reducing waste. At the same time, since most of the surface reactions studied currently occur in an ultra-high vacuum environment, compared with the traditional solution environment, factors such as air oxidation and solvent decomposition are excluded, which helps the direct occurrence of the target reaction. Therefore, the method of using surface reactions is conducive to obtaining target molecules with high yield and purity.

[0005] The general process of the surface reaction is as follows: after the organic molecules are deposited on the surface to form a self-assembled structure, sufficient energy is provided by heating, and under the catalysis of the metal surface, the organic molecules are induced to undergo chemical reactions. The surface reaction is mainly excited by heating, but some surface reactions still cannot occur only by heating. In this case, it is possible to consider introducing foreign metal atoms on the surface to promote the surface reaction in the following two ways: on the one hand, the foreign metal atoms can act as catalysts to increase the reactivity of the system; on the other hand, the co-adsorbed foreign metal atoms can form a metal-organic coordination structure with the organic molecules and serve as a template for subsequent surface reactions. Summary of the Invention

[0006] In order to solve the problems of low yield and the existence of by-products in the synthesis of 1,2-diketone compounds by solution coupling reaction at present, the object of the present invention is to provide a method for synthesizing 1,2-diketone compounds by surface coupling reaction.

[0007] In order to solve the above technical problems, a method for synthesizing 1,2-diketone compounds by surface coupling reaction according to the present invention specifically includes the following steps:

[0008] Step 1: Perform cyclic argon etching-annealing treatment on the Au(111) surface to obtain a clean Au(111) surface;

[0009] Step 2: Deposit 1,3,5-tris(p-formylphenyl)benzene molecules (TFPB) and iron atoms (Fe) onto the clean Au(111) surface in sequence to obtain a metal substrate with 1,3,5-tris(p-formylphenyl)benzene molecules and iron atoms;

[0010] Step 3: Anneal the metal substrate obtained in Step 2 to obtain a metal substrate with 1,2-diketone compounds.

[0011] Further, in Step 1, the specific steps are as follows: Transfer the Au(111) metal single crystal substrate into the sample preparation chamber, slowly open the leak valve, and introduce argon gas into the chamber; wait until the air pressure rises to 2.5×10 -5 mbar, adjust the argon etching parameters, set the argon ion energy to 1.5 keV, and perform argon etching for 15 minutes; after the argon etching is completed, use the EBH-150 electron beam heating device to raise the substrate temperature to 577 °C to complete the high-temperature annealing treatment; repeat the above argon etching-annealing operation 5 times to obtain a clean Au(111) surface.

[0012] Further, in Step 2, the 1,3,5-tris(p-formylphenyl)benzene molecules are deposited by OMBE organic molecule evaporation technology, and the deposition temperature is controlled at 105 °C and the deposition time is 20 minutes.

[0013] Further, in Step 2, iron atoms are deposited by electron beam evaporation technique, and the fusing current and high voltage are controlled to be 4.5 nA and 1.5 kV respectively, and the deposition time is 10 minutes.

[0014] Further, in Step 3, the annealing temperature is 200 °C and the heat preservation time is 15 minutes.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0016] (1) The present invention synthesizes 1,2-diketone compounds by the method of surface coupling reaction. The preparation process is simple and controllable, avoiding the use of dangerous reagents, and the reaction rate of raw material molecules is higher, reducing waste.

[0017] (2) The synthesized 1,2-diketone compounds have high yields and no by-products are generated.

[0018] (3) The synthesized 1,2-diketone compounds, as an important raw material for organic synthesis, can be widely applied to the synthesis and preparation fields such as medicine, chemical engineering and polymer materials. Description of the Drawings

[0019] Figure 1 The STM scanning image and ball-and-stick model of the self-assembled structure formed after the TFPB molecules in Example 1 of the present invention are deposited on the Au(111) surface at room temperature: (a) A large-scale STM scanning image (100×100 nm); (b) A high-resolution STM scanning image (5.2×5.2 nm), superimposed with an optimized model of the self-assembled structure.

[0020] Figure 2 The STM scanning image and ball-and-stick model of the TFPB-Fe metal-organic coordination structure formed after the TFPB molecules and Fe atoms in Example 1 of the present invention are successively deposited on the Au(111) surface: (a) A large-scale STM scanning image (50×50 nm); (b) A high-resolution STM scanning image (5.2×5.2 nm), superimposed with an optimized model of the metal-organic coordination structure.

[0021] Figure 3 The STM scanning image and ball-and-stick model of the 1,2-diketone compounds obtained by the surface coupling reaction after the TFPB molecules and Fe atoms in Example 1 of the present invention are successively deposited on the Au(111) surface and annealed at 200 °C: (a) A large-scale STM scanning image (80×80 nm); (b) A high-resolution STM scanning image (5.2×5.2 nm), superimposed with an optimized model of the covalent dimer.

[0022] Figure 4STM large-scale scan image (100×100 nm) after annealing at 200 °C of TFPB molecules of Comparative Example 1 of the present invention deposited on the Au(111) surface.

[0023] Figure 5 STM large-scale scan image (50×50 nm) of 1,2-diketone compounds obtained by surface coupling reaction after annealing at 200 °C when TFPB molecules and Fe atoms of Comparative Example 2 of the present invention were successively deposited on the Au(111) surface.

[0024] Figure 6 Bar graph of the yield obtained by counting the number of TFPB molecules that underwent surface coupling reaction to form 1,2-diketone compounds and the number of unreacted TFPB molecules on the annealed metal substrates in Example 1 and Comparative Example 2 of the present invention. Detailed implementation manners

[0025] The method for synthesizing 1,2-diketone compounds by surface coupling reaction in the present invention enables TFPB molecules to undergo aldehyde group dehydrogenation and intermolecular carbon-carbon coupling under the catalysis of Fe atoms on the Au(111) surface to synthesize 1,2-diketone compounds, which specifically includes the following steps:

[0026] Step 1: Perform cyclic Ar etching-annealing treatment on the Au(111) surface to obtain a clean Au(111) surface;

[0027] Step 2: First, use the OMBE organic molecule evaporation technique to deposit TFPB molecules on the clean Au(111) surface at a deposition temperature of 105 °C and a deposition time of 20 minutes to obtain a metal substrate with TFPB molecules; then use the electron beam evaporation technique to raise the fusing current and high voltage to 4.5 nA and 1.5 kV respectively, and at this time deposit Fe atoms on the metal substrate with TFPB molecules for 10 minutes to obtain a metal substrate with TFPB molecules and Fe atoms;

[0028] Step 3: Anneal the metal substrate obtained in Step 2 to 200 °C and keep it warm for 15 minutes, and then cool it naturally to obtain a metal substrate with 1,2-diketone compounds.

[0029] The chemical reaction process for synthesizing 1,2-diketone compounds by surface coupling reaction in the present invention is as follows:

[0030]

[0031] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0032] Example 1

[0033] Step 1: Perform cyclic argon etching - annealing treatment on the Au(111) surface to obtain a clean Au(111) surface. The specific steps are as follows: Transfer the Au(111) metal single - crystal substrate into the sample preparation chamber, slowly open the leak valve, and introduce argon gas into the chamber; when the gas pressure rises to 2.5×10 -5 mbar, adjust the argon etching parameters, set the argon ion energy to 1.5 keV, and etch for 15 minutes. After argon etching, use the EBH - 150 electron beam heating device to raise the substrate temperature to 577 °C to complete the high - temperature annealing treatment. Repeat the above argon etching - annealing operation 5 times to obtain a clean Au(111) surface.

[0034] Step 2: At room temperature, deposit a certain proportion of TFPB molecules and Fe atoms onto the clean Au(111) surface successively. The specific steps are as follows: Load the TFPB molecules into a crucible, install it on the molecular source, then install the molecular source into the rapid injection chamber and evacuate. When the gas pressure in the chamber is less than 8×10 -8 mbar, use the OMBE organic molecule evaporation technique to raise the temperature to 105 °C. At this time, the TFPB molecules are deposited onto the clean Au(111) surface, and control the deposition time to be 20 minutes to obtain a metal substrate with TFPB molecules. Transfer the metal substrate into the sample observation chamber and observe it using STM. It can be observed that at room temperature, the hydrogen - bond self - assembly structure formed by complete TFPB molecules on the Au(111) surface (such as Figure 1 a in it), combined with DFT calculation, its optimized model can be obtained (such as Figure 1 b in it); Transfer the metal substrate with TFPB molecules into the rapid injection chamber, load the iron rod into the metal source, then install the metal source into the rapid injection chamber and evacuate. When the gas pressure in the chamber is less than 8×10 -8 mbar, use the electron beam evaporation technique to raise the fusing current and high voltage to 4.5 nA and 1.5 kV respectively. At this time, Fe atoms are deposited onto the metal substrate with TFPB molecules, and control the deposition time to be 10 minutes to obtain a metal substrate with TFPB molecules and Fe atoms. Transfer the metal substrate into the sample observation chamber and observe it using STM. It can be observed that at room temperature, the TFPB - Fe metal - organic coordination structure formed by complete TFPB molecules and Fe atoms on the Au(111) surface (such as Figure 2 a in it), combined with DFT calculation, its optimized model can be obtained (such as Figure 2 b in it). This metal - organic coordination structure is formed by the coordination of the oxygen atom on the aldehyde group of the TFPB molecule with the Fe atom.

[0035] Step 3: Transfer the metal substrate with TFPB molecules and Fe atoms into the sample preparation chamber. Heat the metal substrate to 200 °C using the EBH-150 electron beam heating device and hold for 15 minutes, then cool it naturally to obtain the annealed metal substrate. Transfer the metal substrate into the sample observation chamber and observe it using STM. The formation of covalent oligomer structures can be observed, mainly covalent dimer structures, which appear as dog-bone shaped in the STM scan image (such as Figure 3 in a), and by combining DFT calculations, its optimized model can be obtained (such as Figure 3 in b). These covalent oligomers are formed by carbon-hydrogen activation of the aldehyde groups on the TFPB molecules, followed by further carbon-carbon coupling to form carbon-carbon single bonds, and belong to 1,2-diketone compounds. As Figure 6 shown, count the number of TFPB molecules that undergo surface coupling reactions to form covalent oligomers and the number of unreacted TFPB molecules. The calculated yield is 87.4%. Compared with the coupling method in solution, the yield of 1,2-diketone compounds is significantly increased, and there are no by-products generated in the reaction.

[0036] Comparative Example 1

[0037] Step 1: The same as Step 1 in Example 1.

[0038] Step 2: At room temperature, deposit TFPB molecules onto the clean Au(111) surface. The specific steps are as follows: Load the TFPB molecules into a crucible, install it on the molecular source, then install the molecular source into the rapid injection chamber and evacuate. When the pressure in the chamber is less than 8×10 -8 mbar, use the OMBE organic molecular evaporation technique to raise the temperature to 105 °C. At this time, the TFPB molecules are deposited onto the clean Au(111) surface, and control the deposition time to 20 minutes to obtain the metal substrate with TFPB molecules.

[0039] Step 3: Transfer the metal substrate with TFPB molecules into the sample preparation chamber. Heat the metal substrate to 200 °C using the EBH-150 electron beam heating device and hold for 15 minutes, then cool it naturally to obtain the annealed metal substrate. Transfer the metal substrate into the sample observation chamber and observe it using STM. As Figure 4 shown, only the bare Au(111) surface can be observed. This is because no foreign Fe atoms are introduced as catalysts at this time, so the TFPB molecules cannot undergo surface coupling reactions to synthesize 1,2-diketone compounds after annealing, but will directly desorb from the Au(111) surface.

[0040] Comparative Example 2

[0041] Step 1: The same as Step 1 in Example 1.

[0042] Step 2: At room temperature, deposit a certain proportion of TFPB molecules and Fe atoms onto the clean Au(111) surface successively. The specific steps are as follows: Load the TFPB molecules into a crucible, install it on the molecular source, then install the molecular source into the rapid injection chamber and evacuate it. When the chamber pressure is less than 8×10 -8 mbar, use the OMBE organic molecule evaporation technique to raise the temperature to 105 °C. At this time, the TFPB molecules are deposited onto the clean Au(111) surface. Control the deposition time to be 10 minutes to obtain a metal substrate with TFPB molecules; Load an iron rod into the metal source, then install the metal source into the rapid injection chamber and evacuate it. When the chamber pressure is less than 8×10 -8 mbar, use the electron beam evaporation technique to raise the fusing current and high voltage to 4.5 nA and 1.5 kV respectively. At this time, the Fe atoms are deposited onto the metal substrate with TFPB molecules. Control the deposition time to be 10 minutes to obtain a metal substrate with TFPB molecules and Fe atoms.

[0043] Step 3: Transfer the metal substrate with TFPB molecules and Fe atoms into the sample preparation chamber. Heat the metal substrate to 200 °C with an EBH-150 electron beam heating device and keep it warm for 15 minutes, then cool it naturally to obtain an annealed metal substrate. Transfer the metal substrate into the sample observation chamber and observe it with STM. As Figure 5 shown, because the deposition time of the TFPB molecules is shortened, resulting in a decrease in their surface coverage, it can be observed that compared with Example 1, the surface coverage of the product after the surface coupling reaction decreases. As Figure 6 shown, count the number of TFPB molecules that undergo surface coupling reaction to form covalent oligomers and the number of unreacted TFPB molecules. The calculated yield is 82.5%, which is close to the yield of Example 1. Compared with Example 1, the deposition time of the TFPB molecules in Comparative Example 2 is shortened, and the deposition time of the Fe atoms remains unchanged. Finally, the yield of the 1,2-diketone compound in Comparative Example 2 is similar to that of Example 1, indicating that the deposited Fe atoms in Example 1 are sufficient.

Claims

1. A method for synthesizing 1,2-diketone compounds through surface coupling reaction, characterized in that, Specifically, it includes the following steps: Step 1: Perform cyclic argon etching-annealing treatment on the Au(111) surface to obtain a clean Au(111) surface; Step 2: Deposit 1,3,5-tris(4-formylphenyl)benzene molecules and iron atoms onto the clean Au(111) surface successively to obtain a metal substrate with 1,3,5-tris(4-formylphenyl)benzene molecules and iron atoms; Step 3: Anneal the metal substrate obtained in Step 2 to obtain a metal substrate with 1,2-diketone compounds; Among them, the 1,2-diketone compound has the following structure:

2. The method according to claim 1, characterized in that In Step 1, the specific steps are: Transfer the Au(111) metal single crystal substrate into the sample preparation chamber, slowly open the leak valve, and introduce argon gas into the chamber; Wait for the air pressure to rise to 2.5×10 -5 mbar, adjust the argon etching parameters, set the argon ion energy to 1.5 keV, and etch for 15 minutes; after the argon etching is completed, use the EBH-150 electron beam heating device to raise the substrate temperature to 577 °C to complete the high-temperature annealing treatment; repeat the above argon etching-annealing operation 5 times to obtain a clean Au(111) surface.

3. The method according to claim 1, wherein In Step 2, deposit 1,3,5-tris(4-formylphenyl)benzene molecules by OMBE organic molecular evaporation technology, control the deposition temperature at 105 °C, and the deposition time at 20 minutes.

4. The method according to claim 1, characterized in that, In Step 2, deposit iron atoms by electron beam evaporation technology, control the fusing current and high voltage at 4.5 nA and 1.5 kV respectively, and the deposition time at 10 minutes.

5. The method according to claim 1, wherein In Step 3, the annealing temperature is 200 °C, and the heat preservation time is 15 minutes.

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