Supramolecular-based single-molecule device for detecting small molecule gas and preparation method thereof

Abstract

The present application relates to the technical field of single molecule device, and especially relates to a single molecule device for detecting small molecule gas based on supramolecule and a preparation method thereof. The single molecule device comprises a pair of graphene electrodes and a functional molecule, and the functional molecule is connected between the pair of graphene electrodes through an amide bond. A cucurbituril hydrophobic cavity structure in a structural formula of the functional molecule can accommodate a target small molecule gas, selectively encapsulate gas molecules of different volumes through multiple weak interactions, form a dynamic controllable host-guest complex structure, and then realize "on-off type" sensing and detection of the small molecule gas. Amino terminals at end portions of a host bridging unit in the functional molecule can be connected with carboxyl terminals of the graphene point electrodes through a covalent bond, and a molecular chain connected through amide condensation is formed at both ends of the graphene point electrodes, so that the stability of the single molecule device is improved. The preparation method provided by the present application is simple in process, mild in reaction condition, controllable, and beneficial to large-scale production.

Description

Technical Field

[0001] This invention relates to the field of single-molecule device technology, and in particular to single-molecule devices for detecting small molecule gases based on supramolecular structures and their preparation methods. Background Technology

[0002] The detection of small molecule gases such as hydrogen, oxygen, nitrogen, methane, carbon monoxide, and carbon dioxide is widely used in scientific research and production fields such as energy, environmental monitoring, catalytic reactions, and gas separation and purification. Currently, small molecule gas detection technology is showing a diversified development trend, but it still faces many challenges. Among traditional detection methods, electrochemical sensors are low-cost but easily affected by environmental humidity and temperature, leading to fluctuations in detection accuracy. For example, the detection error for carbon dioxide can exceed 15% in high humidity environments. Optical sensing technologies (such as infrared spectroscopy), while possessing high selectivity, are limited by large equipment size and difficulty in achieving portable detection. Gas chromatography, although capable of simultaneous analysis of multiple gas components, has a long detection cycle, making it difficult to meet real-time monitoring needs. With the upgrading demands in fields such as energy security and environmental governance, higher requirements are placed on the sensitivity, response speed, and anti-interference capabilities of small molecule gas detection, which traditional technologies can no longer fully meet.

[0003] Single-molecule devices are nanoscale devices that use a single molecule as the core functional unit and achieve specific functions through the molecule's own electronic, optical, mechanical, or chemical properties. They represent the forefront of nanotechnology and molecular electronics. As ultra-miniature devices with specific functions at the molecular level, single-molecule devices are not only technologically significant but also play a crucial role in scientific exploration and future industrial development. As a core research direction in molecular electronics, single-molecule devices have made progress in fabrication processes and functional exploration in recent years. Through mechanically controllable splitting techniques and electromigration methods, precise connections between single molecules and electrodes can be achieved, enabling the construction of single-molecule devices with rectification and switching functions. For example, a light-controlled single-molecule switch based on diarylene molecules can achieve an on / off ratio exceeding 10². In the field of gas detection, single-molecule devices, with their size advantage at the single-molecule level, can theoretically achieve single-molecule recognition of gas molecules, with sensitivity far exceeding that of traditional devices. However, there are still prominent problems in this field: First, the devices are unstable, and the interface between molecules and electrodes is easily affected by environmental factors (such as temperature, humidity, and gas atmosphere), resulting in short device lifespan and short continuous working time for most devices; Second, signal reading is difficult, as the electrical signals of single-molecule devices are weak (usually at the pA level) and easily interfered with by background noise, requiring the support of high-precision detection systems; Third, large-scale preparation is difficult, and existing technologies cannot achieve batch and uniform preparation of single-molecule devices, which restricts their practical application. Summary of the Invention

[0004] The present invention aims to at least solve one of the technical problems existing in the related art. Therefore, the first objective of the present invention is to provide a single-molecule device for detecting small molecule gases based on supramolecular structures; the second objective of the present invention is to provide a method for preparing such a device.

[0005] To achieve the first objective, the technical solution adopted by this invention is as follows:

[0006] A single-molecule device for detecting small molecule gases based on supramolecular structures includes functional molecules and graphene electrode pairs, wherein the functional molecules are connected between the graphene electrode pairs via amide bonds.

[0007] The structural formula of the functional molecule is shown below:

[0008] n1 is selected from any integer from 1 to 4;

[0009] in, As a hydrophobic cavity unit, it is used to capture small molecule gases;

[0010] As the main bridging unit, the -NH2 at both ends of the main bridging unit is dehydrated and condensed with -COOH on the graphene electrode pair to form amide bonds.

[0011] Single-molecule devices with functional molecules formed by supramolecular structures offer significant advantages over traditional single-molecule devices. The hydrophobic cavity unit, with its cucurbita-like cavity structure, can accommodate and capture target small gas molecules such as CH4 and CO. Through multiple weak interactions, it selectively encapsulates gas molecules of different volumes, forming a dynamically tunable host-guest complex structure. The binding process causes changes in the molecular bridge configuration or charge distribution on the single-molecule device, significantly altering the conductivity signal and enabling a "switch-type" sensor for detecting small gas molecules. Simultaneously, utilizing the temperature sensitivity of the supramolecular structure with its cucurbita-like structure, adsorption-desorption of small gas molecules can be achieved, reflected in the conductivity signal, thus enabling the capture and detection of small gas molecules with good reproducibility. The host bridging unit has a carbazole derivative structure. Its amino terminus can be covalently linked to the carboxyl terminus of the graphene point electrode, forming an amide condensation molecular chain at both ends of the graphene point electrode, improving the stability of the single-molecule device.

[0012] Preferably, a single functional molecule is connected between the graphene electrode pairs.

[0013] Preferably, the graphene electrode is an array electrode.

[0014] Preferably, the graphene electrode is a nano-gap electrode.

[0015] To achieve the second objective, the technical solution adopted by this invention is as follows:

[0016] A method for fabricating a single-molecule device for detecting small molecule gases based on supramolecular structures, as described in any of the above-mentioned methods, includes the step of connecting a functional molecule to a graphene electrode pair via an amide bond, as follows:

[0017] S100. Using a condensation reaction, graphene electrode pairs are acylated to obtain graphene electrode pairs containing acyl groups.

[0018] S200. Place the graphene electrode pair containing acyl groups in an organic solution of a functional molecular compound with a concentration of not less than 1 mM, and react for 0.5 to 1 h. The functional molecule and the graphene electrode pair are connected by amide bonds to form a molecular chain, thereby obtaining a single-molecule device for detecting small molecule gases based on supramolecular structures.

[0019] Preferably, in step S100, the condensing agent used in the condensation reaction is selected from oxalyl chloride.

[0020] Preferably, in step S100, the catalyst used in the condensation reaction is selected from anhydrous aluminum chloride, and the reaction solvent is selected from dichloromethane.

[0021] Preferably, in step S200, the solvent used to prepare the organic solution of the functional molecular compound is tetrachloroethane.

[0022] Preferably, the preparation method of the functional molecule is as follows:

[0023] S210, using cucurbitacin Preparation of compound I containing hydrophobic cavity units n is selected from any integer from 5 to 8;

[0024] S220, with and Using raw materials, intermediates are prepared. ;

[0025] S230. Using the azidation reaction that occurs in the intermediate, compound II is prepared. ;

[0026] S240. Utilizing the reaction of compound I and compound II to generate supramolecular structures, functional molecules are obtained. .

[0027] Preferably, in preparation step S230, the azide reagent used in the azide reaction is selected from... .

[0028] The above-described one or more technical solutions in the embodiments of the present invention have at least one of the following technical effects:

[0029] This invention provides a supramolecular-based single-molecule device for detecting small molecule gases and its fabrication method. The single-molecule device comprises a functional molecule and a graphene electrode pair. The functional molecule is connected between the graphene electrode pairs via amide bonds. The structural formula of the functional molecule is as follows: The cucurbita hydrophobic cavity structure in this design can accommodate and capture target small molecule gases (such as CH4 and CO). Through multiple weak interactions, it selectively encapsulates gas molecules of different volumes, forming a dynamically tunable host-guest complex structure. The binding of gas molecules to functional molecules causes changes in the configuration or charge distribution of the molecular bridges on the single-molecule device, significantly altering the conductivity signal and enabling "switch-type" sensing and detection of small molecule gases. Simultaneously, utilizing the temperature sensitivity of the supramolecular structure with the cucurbita structure, adsorption-desorption of small molecule gases can be achieved. This adsorption-desorption process can be reflected by the conductivity signal, thus enabling the capture and detection of small gas molecules with good reproducibility. The main bridging unit has a carbazole derivative structure, and its amino terminus can be covalently connected to the carboxyl terminus of the graphene point electrode, forming an amide condensation molecular chain connection at both ends of the graphene point electrode, improving the stability of the single-molecule device.

[0030] The method for preparing single-molecule devices for detecting small molecule gases based on supramolecular structures provided by this invention is simple, with mild and controllable reaction conditions, which is conducive to large-scale production.

[0031] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the structure of a single-molecule device for detecting small molecule gases based on supramolecular structures, provided in an embodiment of the present invention.

[0033] Figure 2 This is a graph showing the It curve test results of the graphene device without connected functional molecules provided in the embodiments of the present invention.

[0034] Figure 3 This is a graph showing the It curve test results of a single-molecule device for detecting small molecule gases based on supramolecular structures, provided in an embodiment of the present invention.

[0035] Figure 4 This is a graph showing the It curve test results of a single-molecule device for detecting small molecule gases based on supramolecular structures under an H2 atmosphere, as provided in an embodiment of the present invention.

[0036] Figure 5 This is a graph showing the It curve test results of a single-molecule device for detecting small molecule gases based on supramolecular structures in a CH4 atmosphere, as provided in an embodiment of the present invention.

[0037] Figure Labels

[0038] 1. Functional molecules; 2. Graphene electrode pairs. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention. The following embodiments are used to illustrate this invention, but cannot be used to limit the scope of this invention.

[0040] In the following embodiments, unless otherwise specified, the experimental methods used are conventional methods, and the materials and reagents used are commercially available, unless otherwise specified, and are carried out in accordance with the techniques or conditions described in the literature in this field or in accordance with the product instructions.

[0041] like Figure 1 As shown, a single-molecule device for detecting small molecule gases based on supramolecular structures includes a functional molecule 1 and a graphene electrode pair 2, wherein the functional molecule 1 is connected to the graphene electrode pair 2 via amide bonds.

[0042] The structural formulas of the functional molecules are shown below:

[0043] n1 is selected from any integer from 1 to 4;

[0044] in, As a hydrophobic cavity unit, it is used to capture small molecule gases;

[0045] As the main bridging unit, the -NH2 at both ends of the main bridging unit dehydrates and condenses with the -COOH on the graphene electrode pair to form amide bonds.

[0046] In the following embodiments, taking n1-to-1 as an example, the fabrication process of functional molecules and single-molecule devices for detecting small molecule gases based on supramolecular structures is illustrated.

[0047] Example 1

[0048] Preparation of functional molecules The process is as follows:

[0049] I. Preparation of hydroxylated cucurbita[5]urea .

[0050] Cucurbita[5] urea (1 g, 1.204 mmol) was dissolved in 12 M HCl aqueous solution (125 mL), and under nitrogen atmosphere, a 30 wt% hydrogen peroxide H2O solution (65 µL, containing 0.62 mmol of hydrogen peroxide) was added. The reaction mixture was stirred for 48 h under ultraviolet light (254 nm) irradiation. Equal portions of the reaction mixture were then taken and analyzed... 1 The reaction was monitored by H NMR. After the reaction was completed, the solvent was evaporated under reduced pressure to obtain a white solid. The white solid was dissolved in 950 µL of a mixed solvent of H2O and HCOOH (the volume ratio of H2O to HCOOH was 1:1) and loaded onto silica gel 60 (particle size 0.04 to 0.063 mm). It was eluted with a mixed solvent of H2O / AcOH / HCOOH (the volume ratio of H2O, AcOH and HCOOH was 10:10:1.5). The eluent was collected in fractions (no less than 250 fractions, 2 ml each) to obtain hydroxylated cucurbita[5]urea.

[0051] II. Preparation of Compound I .

[0052] The hydroxylated cucurbita[5]urea (20 mg, 23 µmol) prepared by the aforementioned method was dissolved in anhydrous dimethyl sulfoxide (DMSO) (1.5 mL), and then NaH solid (0.4 mmol) was added. After stirring at 25 °C for 3 h, the mixture was cooled to 0 °C, and then propargyl bromide (4.4 mmol) was added. After stirring at 25 °C for 12 h, diethyl ether (50 mL) was added to obtain a precipitate. The precipitate was washed three times with MeOH (25 mL) and dried under high vacuum (pressure ≤ 0.1 kPa) to obtain compound I.

[0053] III. Preparation .

[0054] Under a nitrogen atmosphere and at 0°C, (3.89 g) was dissolved in H2SO4 (120 mL), then N-bromosuccinimide (8.0 g, 45 mmol) was added. After stirring for 10 h, the reaction was quenched with deionized water (40 mL), and the reaction solution was extracted with dichloromethane (3 × 20 mL). The organic layer was collected, dried with acid anhydride Na2SO4, and purified by silica gel column chromatography. The elution solvent was a petroleum ether / dichloromethane mixed solvent (the volume ratio of petroleum ether to dichloromethane was 1:2). The yield was 87%.

[0055] Under an argon atmosphere, (0.335mmol) 0.67 mmol of CuI (0.03 mmol), 0.03 mmol of L-proline, and 139 mg of K2CO3 (1 mmol) were dissolved in DMSO. The mixture was reacted at 120 °C for 24 h. After quenching the reaction with deionized water (40 mL), the reaction solution was extracted with ethyl acetate (3 × 20 mL). The organic layer was collected, dried with Na2SO4 anhydride, filtered, and the solvent was evaporated under vacuum. The resulting solution was then purified by silica gel column chromatography using a hexane / ethyl acetate mixture (hexane to ethyl acetate volume ratio 3:1). The yield was 90%.

[0056] IV. Preparation .

[0057] Will (6.15 mmol, 2 g) and SnCl2•2H2O (43.07 mmol, 9.2 g) were added to ethanol (60 mL), stirred thoroughly, refluxed at 25 °C for 16 h, quenched with ice water, and the pH of the reaction solution was adjusted to 9 with a 0.1 mol / L NaHCO3 aqueous solution. The reaction solution was then extracted with dichloromethane (3 × 30 mL). The organic layer was collected, dried over MgSO4 anhydride, concentrated under reduced pressure, and the residue was recrystallized from toluene to obtain... The yield was 70%.

[0058] V. Preparation of intermediates .

[0059] The preparation obtained by the aforementioned method (0.5mmol) 0.5 mmol of dichloro(ethylene glycol dimethyl ether) nickel(II) (NiCl2-DME) (0.025 mmol, 5.5 mg) and potassium tert-butoxide (0.55 mmol, 62 mg) were added sequentially to a dried screw-cap test tube with a stir bar. The test tube was then transferred to a glove box. Dichloro(ethylene glycol dimethyl ether) nickel(II) (NiCl2-DME) (0.025 mmol, 5.5 mg) and potassium tert-butoxide (0.55 mmol, 62 mg) were then added to the test tube using a syringe. Dimethyl formamide (DMF) (1.5 mL) was then added, and the test tube was sealed. The reaction was stirred at 60 °C for 20 h. The reaction was then quenched with concentrated hydrochloric acid and deionized water (40 mL, 1:1 volume ratio). The reaction solution was extracted with ethyl acetate, and the organic layer was collected. The collected organic layer was washed with saturated sodium chloride, dried over Na2SO4, and purified by silica gel column chromatography. The eluent was a mixture of n-hexane and ethyl acetate (9:1 volume ratio). The yield was 98%.

[0060] The preparation obtained by the aforementioned method (0.5mmol) (0.5 mmol), bipyridine (7.8 mg, 0.05 mmol), and manganese powder (27 mg, 0.5 mmol) were sequentially added to a dried screw-cap test tube with a stir bar. The test tube was then transferred to a glove box. NiCl2-DME (0.025 mmol, 5.5 mg) and potassium tert-butoxide (0.55 mmol, 62 mg) were then added to the test tube using a syringe. DMF (1.5 mL) was then added, the test tube was sealed, and the reaction was stirred at 60 °C for 20 h. The reaction was quenched with concentrated hydrochloric acid and deionized water (40 mL, 1:1 volume ratio). The reaction solution was extracted with ethyl acetate, and the organic layer was collected. The collected organic layer was washed with saturated sodium chloride, dried over Na2SO4, and purified by silica gel column chromatography. The eluent was a mixture of n-hexane and ethyl acetate (9:1 volume ratio). The yield was 73%.

[0061] VI. Preparation of Compound II .

[0062] The preparation obtained by the aforementioned method (0.5mmol) (0.5 mmol) and triphenylphosphine (13 mg, 0.5 mmol) were added sequentially to a dried screw-cap test tube with a stir bar. The test tube was then transferred to a glove box. Diethyl azodicarbonate (3 mL) and anhydrous THF (15 mL) were then added to the test tube using a syringe. The test tube was sealed, and the reaction was stirred at 25 °C for 2 h. The mixture was then concentrated under reduced pressure and purified by silica gel column chromatography. The elution solvent was a mixture of n-hexane and ethyl acetate (volume ratio of n-hexane to ethyl acetate: 9:1). .

[0063] VII. Synthetic Functional Molecules .

[0064] Under a nitrogen atmosphere, the material prepared according to the aforementioned method was... (0.5 mmol) and (0.5 mmol) was dissolved in an aqueous solution of 55% DMSO, and then tris[(1-benzyl-1H-1,2,3-triazol-4-yl)methyl]amine (TBTA) ((0.5 mmol), CuSO4·5H2O (8 mg, 0.05 mmol) and sodium ascorbate (NaAsc) (39.62 mg, 0.2 mmol) were added sequentially. The mixture was stirred at 25 °C for 10 h, then quenched with deionized water (40 mL), and the reaction solution was extracted with dichloromethane (3 × 20 mL). The organic layer was collected, dried with Na2SO4, and purified by silica gel column chromatography. The elution solvent was a mixture of n-hexane and ethyl acetate (volume ratio of n-hexane to ethyl acetate was 3:1) to obtain the functional molecule. ,That 1 The H NMR characterization results are as follows:

[0065] 1 H NMR (500MHz, chloroform-) d ): δ 8.06(d, J =7.7Hz, 2H), 7.74–7.69(m, 4H), 7.63(d, J =1.9Hz, 2H), 7.63–7.60(m, 4H), 7.56(dd, J =7.7, 2.1Hz, 2H), 7.54–7.50(m, 4H), 6.71–6.66(m, 4H), 5.42(d, J =1.7Hz, 5H), 5.40 (d, J =3.7Hz, 1H), 5.37 (dd, J=4.6, 3.7Hz, 2H), 5.18(s, 2H), 5.13(s, 2H), 5.07(s, 4H), 5.07(s, 4H), 5.06(d, J =1.1Hz, 3H), 5.03(s, 6H), 4.42(t, J =6.3Hz, 2H), 4.21(d, J =5.7Hz, 2H), 4.13(d, J =5.7Hz, 2H), 2.89(t, J =7.7Hz, 2H), 2.22–2.11(m, 2H).

[0066] Example 2

[0067] The fabrication process for a supramolecular-based single-molecule device for detecting small molecule gases is as follows:

[0068] I. Fabrication of devices with graphene electrode pairs.

[0069] Cut the copper sheet into a regular shape with scissors, wearing gloves throughout the process to avoid direct contact with the copper sheet; immerse the copper sheet in ultrapure water and sonicate for 15 minutes, then remove it and rinse it with ethanol to obtain a clean copper sheet.

[0070] A clean copper sheet is placed in a chemical vapor deposition (CVD) furnace and grown at 1030°C for 100 min in a hydrogen and methane atmosphere. After cooling, the sheet is removed to obtain a graphene film grown on the copper sheet.

[0071] A copper sheet with a graphene film was fixed onto a clean glass slide with transparent tape. Polymethyl methacrylate (950 PMMA) polymer was spin-coated at 4000 rpm for 40 s on a spin coater, and then baked at 180°C for 2 min on a hot plate. After cooling, the transparent tape was removed, the copper sheet was inverted, and its back side was etched with oxygen plasma for 45 s.

[0072] Take three clean 200mL petri dishes, label them ①, ②, and ③ respectively, and fill each with 150mL of ultrapure water. Add 10mL of concentrated hydrochloric acid to dish ① and mix thoroughly. Cut the treated copper sheet into small pieces and etch them in a concentrated ferric chloride solution for 4 hours. Use a 1×1 cm... 2 A silicon wafer with a thickness of 675±25μm was used to remove the graphene film floating on the surface of the ferric chloride solution and place it in ① to stand for 15 minutes; then the silicon wafer was used to transfer the graphene films in ① one by one to ② to stand for 15 minutes, and then transferred to ③ for treatment in the same way.

[0073] The graphene films in section ③ were individually fixed at a depth of 1×1 cm. 2Place it on a silicon wafer with a thickness of 675±25μm and let it air dry overnight in a cool, dry place.

[0074] The dried sample was placed in a crystallizing dish, and acetone was added to cover the sample. The sample was heated at 80°C for 8 minutes on a hot plate to remove PMMA. The sample was then placed in ethanol and dried with a nitrogen gun to obtain a single-layer graphene film.

[0075] The monolayer graphene film was subjected to spin coating and photolithographic marking: the resist was spin-coated at 4000 rpm for 40s on a spin coater, and then heated at 110℃ for 3min on a hot stage after spin coating; the photolithography mark was then performed with an exposure time of 4s. After photolithography of all samples, the samples were developed with a 1:7 diluted developer (the developer was a mixture of methyl isobutyl ketone and ultrapure water in a volume ratio) to obtain the mark.

[0076] The labeled and developed graphene samples were subjected to magnetron sputtering: under a vacuum of 0.0006 Pa, chromium was pre-sputtered (50 W, 30 s), followed by formal chromium sputtering (50 W, 100 s); then gold was pre-sputtered (50 W, 30 s), followed by formal gold sputtering (50 W, 100 s).

[0077] The coated sample was immersed in acetone and sonicated for 5 minutes to remove the gold foil outside the marking, thus obtaining a gold-marked graphene electrode pair array.

[0078] Photolithography strip processing: Photoresist was spin-coated at 4000 rpm for 40 seconds on a spin coater. After spin coating, the strips were heated at 110°C for 3 minutes on a hot stage. The exposure time for photolithography strips was set to 4 seconds. After photolithography of all samples, the strips were developed using a developer diluted 1:7 (the developer is a mixture of methyl isobutyl ketone and ultrapure water in a volume ratio) to obtain the strips. The developed samples were then etched under reactive ion etching (RIE) oxygen plasma for 45 seconds, leaving only the portion protected by the strips unetched.

[0079] The sample surface after oxygen plasma etching was rinsed with acetone and then subjected to photolithography electrode treatment: photoresist was spin-coated at 4000 rpm for 40s on a spin coater, and then heated at 110℃ for 3min on a hot stage after spin coating; the exposure time for photolithography electrode was set to 4s. After photolithography treatment of all samples, they were developed with a developer diluted at a volume ratio of 1:7 (the developer is a mixture of methyl isobutyl ketone and ultrapure water in a volume ratio) to obtain a graphene electrode pair array.

[0080] The graphene electrode array was placed on a spin coater and PMMA was spin-coated at 4000 rpm for 40 s. After spin coating, the electrode was heated at 180°C for 2 min on a hot stage for electron beam exposure. After treatment, the electrode was developed with a developer diluted 1:3 (the volume ratio of developer to isopropanol was 1:3) for about 18 s. After fixing with isopropanol, the electrode was observed under a 100× microscope, and clear graphene nanostrip gaps were obtained.

[0081] Anhydrous aluminum chloride (0.2 g) was placed in a 100 mL two-necked flask and dissolved in tetrachloroethane (40 mL). The mixture was stirred at 500 rpm for 10 h in an anhydrous environment at 25 °C. Then, oxaloyl chloride (0.4 mL) was injected into the reaction system. The treated device was placed flat in the two-necked flask, connected to a condenser, and reacted at 99 °C for 12 h to obtain an array of terminally amidated graphene electrode pairs. The graphene device was gently removed from the two-necked flask, rinsed with dichloromethane, and then immersed in ultrapure water containing glacial acetic acid for 15 min. It was then dried with a nitrogen gun to obtain a device containing acyl graphene electrode pairs. Current testing was performed on the device at 25 °C. The It curve test results are as follows: Figure 2 As shown.

[0082] Devices containing acyl graphene electrode pairs are placed in a 1 mM concentration of functional molecules. After soaking in dichloromethane solution for 1 hour, the device was removed with tweezers and rinsed with ultrapure water. This rinsing process was repeated three times, followed by drying with a nitrogen gun to obtain a single-molecule device for detecting small molecule gases based on supramolecular technology. Current testing was performed on the device at room temperature (25℃), and the It curve results are as follows: Figure 3 As shown.

[0083] The supramolecular-based single-molecule device for detecting small molecule gases was immersed in ultrapure water containing H2 or CH4 for 15 min, removed with tweezers, and dried with a nitrogen gun. The It curves of the single-molecule device were then measured at room temperature (25°C). The results are as follows: Figure 4 and Figure 5 As shown.

[0084] The performance testing process for the above-mentioned devices is as follows: At room temperature of 25℃, the single-molecule device for detecting small molecule gases based on supramolecular technology is placed under a probe station, which is connected to an active meter; the bias voltage is fixed at 0.5 V, and the change of current over time is tested to obtain the It curve.

[0085] The single-molecule device for detecting small molecule gases based on supramolecular structures was heated at 50°C for 3 minutes on a heating stage, followed by an It test under a 0.5V bias voltage. The results showed that heating can cause the single-molecule device for detecting small molecule gases based on supramolecular structures to release small gas molecules, thus indirectly proving that supramolecular structures can achieve the encapsulation, detection and release of small molecule gases.

[0086] The current change over time of the single-molecule device for detecting small molecule gases based on supramolecular structures was tested at room temperature of 25℃ after a seven-day interval. The results showed that the It test results had good reproducibility, proving that the prepared graphene-based single-molecule-gas small molecule detector had good performance.

[0087] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A single-molecule device for detecting small gaseous molecules based on supramolecules, characterized in that, The functional molecule and the graphene electrode pair are connected by an amide bond. The structure of the functional molecule is shown as follows: n1 is selected from any integer between 1 and 4 inclusive; wherein, as a hydrophobic cavity unit for capturing small molecule gases; As the host bridging unit, -NH2 at both ends of the host bridging unit respectively dehydrates and condenses with -COOH on the graphene electrode pair to form an amide bond connection.

2. The supramolecular-based monolayer device for detecting small gaseous molecules according to claim 1, wherein, A single functional molecule is connected between the graphene electrode pair.

3. The supramolecular-based monolayer device for detecting small gaseous molecules according to claim 1, wherein The graphene electrode is an array electrode.

4. The supramolecular-based monolayer device for detecting small gaseous molecules according to claim 1, wherein The graphene electrode is a nano-gap electrode.

5. A method for producing a single-molecule device for detecting a small molecule gas based on a supramolecule, characterized by, A method for preparing a supramolecular-based monomolecular device for detecting small molecule gas according to any one of claims 1 to 4, comprising the step of connecting a functional molecule to a graphene electrode pair by an amide bond, the process being as follows: S100, acylating the graphene electrode pair by a condensation reaction to obtain an acyl-containing graphene electrode pair; S200, placing the acyl-containing graphene electrode pair in an organic solution of a functional molecule compound with a concentration not less than 1 mM, and reacting for 0.5-1 h, so that the functional molecule is connected to the graphene electrode pair by an amide bond to form a molecular link, thereby obtaining a supramolecular-based monomolecular device for detecting small molecule gas.

6. The preparation method of the supramolecular-based monomolecular device for detecting small gaseous molecules according to claim 5, wherein, In step S100, the condensing agent used in the condensation reaction is selected from oxalyl chloride.

7. The supramolecular-based monomolecular device production method for detecting small molecule gases according to claim 5, wherein In step S100, the catalyst used in the condensation reaction is selected from anhydrous aluminum chloride, and the reaction solvent is selected from dichloromethane.

8. The preparation method of the supramolecular-based monomolecular device for detecting small gaseous molecules according to claim 5, wherein, In step S200, the solvent used for preparing the organic solution of the functional molecule compound is tetrachloroethane.

9. The preparation method of the supramolecular-based monomolecular device for detecting small gaseous molecules according to claim 5, wherein, The preparation method of the functional molecule is as follows: S210, using cucurbituril to produce compound I having a hydrophobic cavity unit n is any integer from 5 to 8; S220、with and as starting materials, to prepare the intermediate ； S230, preparing compound II by an azidation reaction of the intermediate; ； S240, generating a supramolecular structure by a reaction of compound I and compound II to obtain a functional molecule. 。 10. The supramolecular-based monomolecular device production method for detecting small molecule gases according to Claim 9, wherein In the preparation step S230, the azide reagent used in the azide reaction is selected from .

Images