A method for controllable synthesis of metal-organic nanoribbons

Abstract

The application discloses a controllable synthesis method of metal-organic nanobelt, and steps of the method are as follows: iron atoms and TCT molecules are sequentially deposited on a clean Au(111) surface in sequence to obtain a metal base with iron atoms and TCT molecules; and the metal base is subjected to annealing treatment to obtain a heteroatomic C-Fe-N nanobelt structure. The application introduces iron atoms to the surface and controls the ratio of the iron atoms and organic molecules, synthesizes the metal-organic nanobelt, and the product has a single structure and high selectivity. The synthesized metal-organic nanobelt has a C-Fe-N asymmetric bond, compared with a symmetric coordination bond / organic metal covalent bond in a previous metal-organic nanobelt, has unique electromagnetic properties, and has a more extensive application prospect in interdisciplinary applications such as catalysis, information storage and sensors.

Description

Technical Field

[0001] This invention relates to a method for synthesizing one-dimensional metal-organic nanoribbons, belonging to the field of materials preparation technology. Background Technology

[0002] The precise fabrication of relatively robust, well-defined, and novel functional nanostructures on surfaces has attracted widespread attention due to their broad application prospects in the design and development of molecular devices. Metal atoms in metal-organic nanostructures can enrich the electromagnetic properties of organic systems, thus demonstrating enormous application potential in multiple disciplines such as catalysis, information storage, and sensors. Given their potential applications, the selective fabrication of more complex metal-organic nanostructures has become a research hotspot.

[0003] Previous research has largely focused on metal-organic nanostructures containing symmetrical coordination bonds, such as two-coordinate, three-coordinate, and four-coordinate N-metal-N-coordinate nanostructures or C-metal-C organometallic nanostructures. However, research on heterocoordinate metal-organic structures, where metal atoms are simultaneously bonded to mixed ligands or even different functional groups, is limited and remains challenging. This could potentially link novel and unique properties of metal-organic systems. Therefore, establishing heterocoordinate metal-organic nanostructures may involve new chemical phenomena or properties and is of significant research importance. To date, the synthesis of heterocoordinate nanostructures has been carried out in solution. Methods for preparing such structures through solution synthesis generally suffer from low selectivity and often involve the formation of numerous byproducts. Summary of the Invention

[0004] To address the current difficulty in synthesizing heterozygous C-Fe-N nanoribbons, the present invention aims to provide a method for rationally selecting heterozygous precursors and synthesizing heterozygous C-Fe-N nanoribbons through a combination of surface synthesis and surface coordination.

[0005] To solve the above-mentioned technical problems, the present invention provides a method for synthesizing heterogeneous C-Fe-N nanoribbons via surface coupling reaction, specifically comprising the following steps:

[0006] Step 1: Iron atoms (Fe) and (cyanuric chloride) TCT molecules are deposited sequentially onto a clean Au(111) surface to obtain a metal substrate with iron atoms and (cyanuric chloride) TCT molecules;

[0007] Step 2: Anneal the metal substrate obtained in Step 1 to obtain heterogeneous C-Fe-N nanoribbon structures.

[0008] Furthermore, in step 1, the clean Au(111) surface is obtained by cyclic argon etching-annealing of the Au(111) surface.

[0009] Furthermore, the specific steps are as follows: An Au(111) metal single crystal substrate is introduced into the sample preparation chamber, and the leak valve is slowly opened to introduce argon gas into the chamber; once the gas pressure reaches 2.5 × 10⁻⁶, the gas is introduced into the chamber. -5 mbar, adjust the argon etching parameters, set the argon ion energy to 1.5keV, and argon etch for 15 minutes; after argon etching, use an EBH-150 electron beam heating device to raise the substrate temperature to 600 K to complete the high-temperature annealing process; repeat the above argon etching-annealing operation 5 times to obtain a clean Au(111) surface.

[0010] Furthermore, in step 1, iron atoms are deposited using electron beam evaporation technology, with the fusing current and high voltage controlled at 4.5 nA and 1.5 kV respectively, and the deposition time being 10 minutes.

[0011] Furthermore, in step 1, TCT molecules are deposited using OMBE organic molecular evaporation technology, with the deposition temperature controlled at 400K and the deposition time at 20 minutes.

[0012] Furthermore, in step 2, the annealing temperature is 500K and the holding time is 15 minutes.

[0013] Compared with the prior art, the beneficial effects of the present invention are:

[0014] (1) The present invention synthesizes heterogeneous C-Fe-N nanoribbons by surface synthesis. The preparation process is simple and controllable, avoids the use of dangerous reagents, and the reaction rate of raw material molecules is higher, reducing waste.

[0015] (2) The synthesized heterogamic C-Fe-N nanoribbons have high selectivity and no byproducts are generated.

[0016] (3) The synthesized heterogamic C-Fe-N nanoribbons, as an important product of organic synthesis, have great application potential in multiple disciplines such as catalysis, information storage and sensors. Attached Figure Description

[0017] Figure 1 The large-size STM image (a) of the metal substrate with Fe atoms and TCT molecules after annealing in Example 1, and the DFT optimization model of its magnified image (b).

[0018] Figure 2 shows a large-size STM image (a), a high-resolution STM image (b), and an overlay of the high-resolution STM image with its DFT-optimized gas phase structure model in Comparative Example 1 containing TCT molecules (c).

[0019] Figure 3 This is a large-scale STM scan (30×30nm) of the metal substrate containing TCT molecules after annealing in Comparative Example 1.

[0020] Figure 4 This is a large-scale STM scan (50×50 nm) of the annealed metal substrate containing Fe atoms and TCT molecules in Comparative Example 2. Detailed Implementation

[0021] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0022] The concept of this invention is as follows: After organic molecules are deposited on a surface to form a self-assembled structure, sufficient energy is provided by heating, and a chemical reaction is induced in the organic molecules under the catalysis of the metal surface. Surface reactions are mainly activated by heating, but some surface reactions cannot occur by heating alone. In this case, it is possible to introduce foreign metal atoms into the surface to promote the surface reaction in two ways: on the one hand, foreign metal Fe atoms can act as catalysts to improve the reactivity of the system; on the other hand, co-adsorbed foreign metal Fe atoms can form metal-organic coordination C-Fe-N nanoribbon structures with organic TCT molecules, serving as templates for subsequent surface reactions.

[0023] The chemical reaction process for synthesizing heterogeneous C-Fe-N nanoribbons via surface coupling reaction in this invention is as follows:

[0024]

[0025] This invention relates to a method for synthesizing heterogeneous C-Fe-N nanoribbons via surface coupling reaction. The method involves the synthesis of heterogeneous C-Fe-N nanoribbons by catalyzing the dehydrogenation of aldehyde groups and intermolecular carbon-carbon coupling of (cyanuric chloride) TCT molecules on an Au(111) surface with Fe atoms. The specific steps include:

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

[0027] Step 2: First, electron beam evaporation technology is used to increase the fusing current and high voltage to 4.5 nA and 1.5 kV respectively, and Fe atoms are deposited onto a clean Au(111) surface for 10 minutes to obtain a metal substrate with Fe atoms; then, OMBE organic molecular evaporation technology is used to deposit TCT molecules onto the surface of the metal substrate with Fe atoms at a deposition temperature of 400K for 20 minutes to obtain a metal substrate with Fe atoms and TCT molecules.

[0028] Step 3: Anneal the metal substrate obtained in Step 2 to 500K and hold for 15 minutes, then cool naturally to obtain a metal substrate with heterogeneous C-Fe-N nanoribbons.

[0029] Example 1

[0030] Step 1: 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 gas pressure rises to 2.5 × 10⁻⁶. -5 The argon etching parameters were adjusted to mbar, with the argon ion energy set to 1.5 keV, and the etching time was 15 minutes. After argon etching, the substrate temperature was raised to 600 K using an EBH-150 electron beam heating device to complete the high-temperature annealing process. The above argon etching-annealing operation was repeated 5 times to obtain a clean Au(111) surface.

[0031] Step 2: At room temperature, insert the iron rod into the metal source, then install the metal source into the rapid injection chamber and evacuate. Wait until the internal pressure is less than 8 × 10⁻⁶. -8 Using electron beam evaporation technology, the fusing current and high voltage were increased to 4.5 nA and 1.5 kV respectively, and the deposition time was controlled at 10 minutes to deposit Fe atoms onto a clean Au(111) surface, resulting in a metal substrate with Fe atoms. TCT molecules were loaded into a crucible, mounted onto a molecular source, and then the molecular source was mounted into a rapid injection chamber. A vacuum was then applied until the pressure inside the chamber was less than 8 × 10⁻⁶. -8 mbar, using OMBE organic molecular evaporation technology, the temperature is raised to 400K and the deposition time is controlled to 20 minutes to deposit TCT molecules onto the surface of a metal substrate containing Fe atoms, resulting in a metal substrate containing Fe atoms and TCT molecules.

[0032] Step 3: The metal substrate containing Fe atoms and TCT molecules is introduced into the sample preparation chamber. The metal substrate is heated to 500K using an EBH-150 electron beam heating device and held at that temperature for 15 minutes. Then it is allowed to cool naturally to obtain the annealed metal substrate containing Fe atoms and TCT molecules.

[0033] An annealed metal substrate containing Fe atoms and TCT molecules was introduced into the sample observation chamber and observed using STM. The formation of covalent oligomeric structures, primarily covalent dimers, was observed, appearing as one-dimensional chain-like structures in the STM scan (e.g., Figure 1 In part a), combined with DFT calculations, its optimized model can be obtained (e.g., Figure 1 (b) These covalent oligomers undergo a dehalogenation reaction through a C-Cl group in the TCT molecule to form a covalent dimer; a C-Cl group in the covalent dimer undergoes a dehalogenation reaction, and the dehalogenated covalent dimers are interconnected through C-Fe-N bonds to form a mixed-type metal-organic hybrid.

[0034] Comparative Example 1

[0035] Step 1: Same as Step 1 in Example 1.

[0036] Step 2: At room temperature, load TCT molecules into a crucible, attach it to the molecular source, then attach the molecular source to the rapid injection chamber and evacuate the chamber until the internal pressure is less than 8 × 10⁻⁶. -8 Using OMBE organic molecular evaporation technology, the temperature was raised to 400K, and the deposition time was controlled at 20 minutes to deposit TCT molecules onto a clean Au(111) surface, resulting in a metal substrate with TCT molecules. The metal substrate with TCT molecules was then transferred into the sample observation chamber and observed using STM. The large-size STM image and the high-resolution STM image are shown below. Figure 2 As shown in a and b in the figure, the self-assembly structure of the TCT molecule can be observed. The DFT-optimized model is then overlaid with the high-resolution image as shown in the figure. Figure 2 As shown in c in the figure.

[0037] Step 3: The metal substrate containing TCT molecules is introduced into the sample preparation chamber. The metal substrate is heated to 500K using an EBH-150 electron beam heating device and held at that temperature for 15 minutes, then allowed to cool naturally to obtain the annealed metal substrate. The metal substrate is then introduced into the sample observation chamber and observed using STM. Figure 3 As shown, desorption occurs at 500K, and no reaction takes place.

[0038] Comparative Example 2

[0039] The other processes are the same as in Example 1, except that in step (2), the deposition time of TCT molecules is changed to 10 minutes.

[0040] An annealed metal substrate containing Fe atoms and TCT molecules was introduced into the sample observation chamber and observed using STM. Figure 4 As shown, because the deposition time of TCT molecules is shortened, their surface coverage decreases. Therefore, compared with Example 1, the surface coverage of the product after the surface coupling reaction is reduced. Compared with Example 1, the deposition time of TCT molecules and Fe atoms in Comparative Example 2 is shortened.

Claims

1. A method for synthesizing misfit C-Fe-N nanoribbons by surface coupling reaction, characterized in that, Specifically comprising the following steps: Step 1: sequentially depositing iron atoms and TCT molecules onto a clean Au(111) surface to obtain a metal substrate with iron atoms and TCT molecules; Step 2: annealing the metal substrate obtained in step 1 to obtain a misfit C-Fe-N nanobelt structure; In step 1, the iron atoms are deposited by electron beam evaporation technology, the control fusing current and high voltage are 4.5 nA and 1.5 kV respectively, and the deposition time is 10 minutes; the TCT molecules are deposited by OMBE organic molecule evaporation technology, the control deposition temperature is 400K, and the deposition time is 20 minutes; In step 2, the annealing temperature is 500K, and the holding time is 15 minutes.

2. The method of claim 1, wherein, In step 1, the clean Au(111) surface is obtained by cyclic argon etching-annealing treatment on the Au(111) surface.

3. The method of claim 2, wherein, The specific steps are as follows: the Au(111) metal single crystal substrate is transmitted into the sample preparation cavity, the leak valve is slowly twisted open, and argon gas is introduced into the cavity; The gas pressure was raised to 2.5 x 10 -5 mbar, the argon etching parameters were adjusted, the argon ion energy was set to 1.5 keV, and argon etching was performed for 15 minutes; after the argon etching was completed, the substrate temperature was raised to 600 K by means of an EBH-150 electron beam heating device, and high-temperature annealing treatment was completed; the above argon etching- annealing operation was repeated 5 times, and a clean Au(111) surface was obtained.

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