A method for preparing one-dimensional graphyne chain

Abstract

The present invention discloses a method for preparing one-dimensional graphyne chains. In this method, a silver single crystal substrate with a (110) crystal plane is selected as a substrate. Precursor molecules, PBDA, are deposited onto the surface of the silver single crystal substrate via molecular beam epitaxy to obtain a self-assembled sample. This self-assembled sample is then gradually annealed to induce molecular polymerization, thereby obtaining one-dimensional graphyne chains connected by carbon-carbon triple bonds. This method provides a method for preparing one-dimensional graphyne chains with high scientific research value and broad application potential.

Description

Technical Field

[0001] The invention belongs to the field of surface synthesis, and in particular relates to a method for preparing a one-dimensional graphyne chain. Background Art

[0002] The carbon-carbon triple bond (–C≡C–) is one of the most fundamental bonding types in organic chemistry. It is not only key to the synthesis of carbon allotropes such as carbenes, graphyne, graphdiyne, and one-dimensional graphyne chains, but also plays an irreplaceable role in mechanistic studies and the fabrication of functionalized devices such as organic solar cells, optical sensors, and organic field-effect transistors. Incorporating sp-hybridized –C≡C– bonds into semiconductor cores can impart exceptional properties. This bonding type is immune to Z / E isomerization, thus avoiding the separation challenges associated with multiple isomers. Furthermore, its introduction enhances molecular rigidity and reduces thermal motion. Furthermore, compared to the other two bonding types, the –C≡C– bond minimizes steric hindrance between adjacent aromatic units, increases molecular planarity, strengthens the backbone π-conjugation, and ultimately improves carrier mobility and spintronic transport.

[0003] Although traditional solution chemistry has successfully synthesized carbon-carbon triple bonds via coupling reactions between two ethyl alkynyl ligands in a trimolybdenum cluster, the high molecular weight of polymers generally leads to a significant reduction in their solubility. Therefore, the in situ preparation of such π-conjugated polymers in solution chemistry remains a significant challenge.

[0004] Notably, one-dimensional graphdiyne chains and two-dimensional graphdiyne macrocycles bridged by diacetylene have been successfully synthesized via dehydrogenation or dehalogenation homocoupling reactions using precursor molecules with terminal alkyne, alkynyl bromide, or trimethylsilane groups. However, the synthesis of acetylene-bridged low-dimensional polymers, the key building blocks of graphdiyne, is primarily achieved through dehalogenation coupling reactions with precursors bearing specific halide substituents (e.g., –CBr3, –CCl3, =CBr2). Furthermore, byproducts produced by dehalogenation reactions, such as dissociated halogen atoms or edge fusion products, may affect the final product structure or the target intrinsic electronic state. Therefore, exploring cleaner and more efficient strategies to integrate acetylene scaffolds into carbon-based nanostructures is crucial for constructing graphdiyne-based materials, which is expected to bring revolutionary breakthroughs to related fields. Summary of the Invention

[0005] To address the aforementioned difficulties in constructing one-dimensional graphyne chains by introducing carbon-carbon triple bonds, the present invention proposes a method for preparing one-dimensional graphyne chains. Specifically, the present invention utilizes the strategy of intermolecular polymerization of PBDA molecules containing acetonitrile groups under the catalytic action of a silver substrate. The precursor PBDA molecule is deposited onto the silver substrate surface and annealed at 190°C for 20 minutes to produce Polymer 1. The sample is then annealed to 250°C for 20 minutes to produce Polymer 2.

[0006] A method for preparing a one-dimensional graphyne chain, the specific steps of which include:

[0007] Step 1, preparing a silver single crystal substrate;

[0008] Step 2: Depositing the precursor molecule PBDA onto a silver single crystal substrate maintained at room temperature by molecular beam epitaxy;

[0009] Step 3: gradually heating the sample, first annealing it to 190°C and keeping it warm for 20 minutes to obtain polymer 1, and then continuing to anneal it to 250°C and keeping it warm for 20 minutes to obtain polymer 2;

[0010] The preparation process of the silver single crystal substrate is specifically as follows:

[0011] Step 1.1, in an ultra-high vacuum chamber, subjecting a silver substrate to argon ion sputtering to obtain a silver base;

[0012] Step 1.2: Heat the silver substrate obtained in step 1.1 to 450° C. and keep it warm for 10-30 minutes to obtain a silver single crystal substrate.

[0013] In step 2, the evaporation temperature of the precursor molecule PBDA is 130° C., and the deposition time is 10 minutes.

[0014] In step 3, the growth temperature of polymer 1 is 190° C. and the temperature is kept at this temperature for 20 minutes. The growth temperature of polymer 2 is 250° C. and the temperature is kept at this temperature for 20 minutes.

[0015] The beneficial effects of the present invention are:

[0016] (1) The present invention utilizes acetonitrile-functionalized precursor molecules to construct carbon-carbon triple bond-bridged polymers;

[0017] (3) The present invention can construct two different polymers in a temperature-controllable manner; BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The embodiment of the present invention shows the reaction path diagram of PBDA molecules on a silver single crystal substrate;

[0019] Figure 2is a scanning tunneling microscope image showing the gradual annealing of the precursor PBDA molecules on the surface of a silver single crystal according to an embodiment of the present invention;

[0020] Figure 3 The embodiment of the present invention shows a high-definition bond-resolved scanning tunneling microscope image and a non-contact atomic force microscope image of a one-dimensional graphyne chain. DETAILED DESCRIPTION

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

[0022] Test instruments and equipment:

[0023] Low-temperature scanning tunneling microscope: purchased from Omicron, Germany.

[0024] K-cell molecular evaporation source: purchased from Omicron, Germany.

[0025] Argon ion gun: purchased from Omicron, Germany.

[0026] raw material:

[0027] Precursor molecule PBDA: synthesized by Professor Chen Long's team at Jilin University, with a purity of 98%.

[0028] Silver single crystal: purchased from MaTecK, purity 99.999%.

[0029] Example

[0030] A method for preparing a one-dimensional graphyne chain, the specific steps of which include:

[0031] Step 1: Prepare a silver single crystal substrate. The preparation process of the silver single crystal substrate is as follows:

[0032] Step 1.1, in an ultra-high vacuum chamber, subjecting a silver substrate to argon ion sputtering to obtain a silver base;

[0033] Step 1.2, heating the silver substrate obtained in step 1.1 to 450° C. and keeping the temperature for 10 minutes to obtain a silver single crystal substrate;

[0034] Step 2: 2 mg of the precursor molecule PBDA was evaporated at 130° C. using a thermal resistance K-cell molecular evaporation source and deposited on the 50 g silver single crystal substrate prepared in step 1 to obtain a substrate and a PBDA self-assembled structure deposited on the substrate. The temperature of the silver single crystal substrate was controlled at 25° C. during the deposition process, and the deposition time was 10 minutes.

[0035] Step 3: gradually increase the temperature of the PBDA molecules on the substrate in step 2 to 190°C, keep the temperature for 20 minutes, and then continue to anneal to 250°C and keep the temperature for 20 minutes;

[0036] The reaction pathway of PBDA molecules on a silver single crystal substrate proposed in this embodiment is as follows: Figure 1 shown.

[0037] The results of the stepwise annealing of PBDA molecules on a silver single crystal substrate proposed in this embodiment are as follows: Figure 2 As shown in Figure 2, at room temperature, PBDA molecules form a head-to-head self-assembled structure on the surface of a silver single crystal. When annealed at 190°C, the molecules aggregate to form a one-dimensional polymer 1, which tends to form two single chains arranged closely together. This is primarily due to weak interactions between the cyano groups and adjacent molecular chains. At 250°C, polymer 1 unravels to form a single strand of polymer 2 on the substrate.

[0038] The one-dimensional graphyne chain prepared in this embodiment is as follows Figure 3 High-resolution bond-resolved scanning tunneling microscopy images and non-contact atomic force microscopy images clearly show that the benzene ring units are connected by carbon-carbon triple bonds, proving the successful synthesis of the one-dimensional graphyne chain.

Claims

1. A method for preparing a one-dimensional graphyne chain, characterized in that The specific steps include: Step 1, preparing a silver single crystal substrate; Step 2: Depositing the precursor molecule PBDA onto a silver single crystal substrate maintained at room temperature by molecular beam epitaxy; Step 3: gradually heating the sample, first annealing it to 190°C and keeping it warm for 20 minutes to obtain polymer 1, and then continuing to anneal it to 250°C and keeping it warm for 20 minutes to obtain polymer 2; The structural formula of the precursor molecule PBDA is ; In step 2, the evaporation temperature of the precursor molecule PBDA is 130° C., and the deposition time is 10 minutes.

2. The method for preparing a one-dimensional graphyne chain according to claim 1, wherein: The preparation process of the silver single crystal substrate is specifically as follows: Step 1.1, in an ultra-high vacuum chamber, subjecting a silver substrate to argon ion sputtering to obtain a silver base; Step 1.2: Heat the silver substrate obtained in step 1.1 to 450° C. and keep it warm for 10-30 minutes to obtain a silver single crystal substrate.

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