Organic molecular wire with adjustable pi-pi stacking effect and preparation method

Abstract

The invention provides an organic molecule wire with an adjustable pi-pi stacking effect and a preparation method, and belongs to the technical field of electrical elements using organic materials as active parts. Thiophene-2-boronic acid pinacol ester and 2-bromothiazole are used as initial raw materials, N-brominated derivatives of a succinimide skeleton and an aromatic boric acid compound are sequentially added, a final product, namely the organic molecular wire, is obtained, the organic molecular wire has donor-acceptor polar centers with different electronic effects, regulation and control on the pi-pi stacking effect can be achieved, and the organic molecular wire has the advantages of being simple in preparation process, low in cost and good in application prospect. The preparation method is simple, wide in substrate applicability, mild in reaction condition and high in reaction efficiency.

Description

Technical Field

[0001] The present application relates to an organic molecular wire with a tunable π-π stacking effect and a preparation method thereof, belonging to the technical field of electrical components using organic materials as the active part. Background Art

[0002] As an important branch of nanoelectronics technology, molecular electronics focuses on the electron transport mechanism at the molecular scale and device fabrication technology. Its core research systems cover two major directions: the analysis of single-molecule conductance behavior and the regulation of interfacial charge transport. Among them, the single-molecule conductance system uses discrete molecules as the basic functional units, showing size advantages close to the physical limit in the field of integrated circuit miniaturization, which has important strategic significance for breaking through the quantum size effect limitation of traditional semiconductor processes (Advanced Electronic Materials, 2023, 9(5), 2201235).

[0003] Since Aviram and Ratner first proposed the theoretical model of molecular rectifiers (the D-A type molecular system can achieve quantum tunneling rectification effect) (Chemical Physics Letters, 1974, 29(2), 277-286), molecular electronics has developed into a complete theory-technology system after decades of development. As the core conduction medium of molecular devices, molecular wires not only undertake the basic function of the electron transport channel, but also are the key building blocks for realizing complex functional devices such as molecular switches (Nature Nanotechnology, 2021, 16(8), 899-907) and molecular transistors (Science, 2020, 368(6493), 878-881). Existing studies have shown (Nano Letters, 2024, 24(1), 189-197) that the charge transport efficiency of molecular wires is closely related to their molecular orbital coupling strength, π-conjugated system extension, and intermolecular interactions. Among them, the π-π stacking interaction, as a typical form of non-covalent interaction, directly affects the carrier mobility and interfacial contact characteristics of molecular wires. However, the existing technologies have the following significant defects:

[0004] (1) Traditional molecular wire designs mostly focus on the regulation of molecular intrinsic conductivity, lacking systematic research on the thermodynamic controllability and kinetic stability of π-π stacking interactions, resulting in insufficient charge transport stability of the assembly;

[0005] (2) Existing synthesis strategies are difficult to achieve the coordinated regulation of multiple electron effects (including but not limited to polarization effects, charge transfer effects, orbital hybridization effects), restricting the development of high-performance molecular wire devices;

[0006] (3) The current methods for preparing molecular wires have problems such as complex synthesis routes and low yields, making it difficult to meet the requirements of large-scale production. Summary of the Invention

[0007] In view of the defects existing in the prior art, the applicant provides an organic molecular wire with a tunable π-π stacking effect, which can isomerize the molecule by connecting different sites of the same donor and acceptor units to achieve the regulation of the π-π stacking effect. The prepared organic molecular wire with a tunable π-π stacking effect can be used for the construction of electronic components.

[0008] Specifically, the present application is achieved through the following solutions:

[0009] An organic molecular wire with a tunable π-π stacking effect, which has a donor-acceptor polar center structure and is expressed by the general formula:

[0010]

[0011] Among them, R1 is any one of H, pyridyl, thiazolyl or thiophenyl, R2 is any one of H, pyridyl, thiazolyl or thiophenyl, and R1 and R2 are not both H at the same time.

[0012] The preparation method of the above-mentioned organic molecular wire with a tunable π-π stacking effect is as follows:

[0013] Step 1: Thiophene-2-boronic acid pinacol ester reacts with 2-bromothiazole to obtain intermediate c.

[0014] The structural formula of intermediate c is:

[0015] Step 2: Intermediate c reacts with an N-bromo derivative having a succinimide skeleton to obtain intermediate d.

[0016] The structural formula of the N-bromo derivative having a succinimide skeleton is:

[0017] The structural formula of intermediate d is:

[0018] In the formula, X is Cl, Br or I;

[0019] Step 3: Intermediate d reacts with an aromatic boronic acid compound to obtain the following final product.

[0020] The structural formula of the aromatic boronic acid compound is: R is any one of H, pyridyl, thiazolyl or thiophenyl.

[0021] The structural formula of the final product is: R1 is any one of H, pyridyl, thiazolyl or thienyl, R2 is any one of H, pyridyl, thiazolyl or thienyl, and R1 and R2 are not both H at the same time.

[0022] Furthermore, as a preference:

[0023] In step one,

[0024] The molar ratio of thiophene-2-boronic acid pinacol ester to 2-bromothiazole is 1.2 - 1.5:1 - 1.1, and the reaction temperature is 45 - 65 °C.

[0025] In step one, palladium acetate and 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene are also added as catalysts. These two catalysts have good solubility in the reaction solvent, and the electron-donating ability of the ligand interacting with palladium contributes to the occurrence of the whole catalytic reaction. More preferably, in addition, a strong basic reagent potassium phosphate can also be added to keep the reaction system in an alkaline environment and promote the reaction equilibrium to shift towards the product direction. The added molar ratio of palladium acetate to 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene is 1:1 - 1.5, and the feeding molar ratio of thiophene-2-boronic acid pinacol ester to palladium acetate is 1:0.02 - 0.025.

[0026] In the reaction of step one, a mixture of toluene and pure water is preferably added as the reaction solvent.

[0027] In step two,

[0028] In a dark environment, an N-bromo derivative with a succinimide skeleton is added, and the molar ratio of intermediate c to the N-bromo derivative with a succinimide skeleton is 1 - 1.2:1 - 1.2.

[0029] In the reaction of step two, N,N-dimethylformamide is preferably added as the reaction solvent.

[0030] In step three,

[0031] The molar ratio of intermediate d to the aromatic boronic acid compound is 1 - 1.2:2 - 2.4, and the reaction temperature is 100 - 120 °C.

[0032] In step three, tetrakis(triphenylphosphine)palladium is also added as a catalyst. This catalyst has good solubility in the reaction solvent, and the electron-donating ability of the ligand interacting with palladium contributes to the occurrence of the whole catalytic reaction.

[0033] In addition, more preferably: A strong basic reagent cesium carbonate can also be added to keep the reaction system in an alkaline environment and promote the reaction equilibrium to shift towards the product direction. The feeding molar ratio of intermediate d to tetrakis(triphenylphosphine)palladium is 1:0.02 - 0.05.

[0034] In the reaction of Step 3, it is preferred to add a mixture of 1,4-dioxane and pure water as the reaction solvent.

[0035] As a specific solution, the structural formula of the organic molecular wire with adjustable π-π stacking effect is At this time, the reaction process is expressed as:

[0036]

[0037] Alternatively, the structural formula of the organic molecular wire with adjustable π-π stacking effect is At this time, its reaction process is expressed as:

[0038]

[0039] In the above preparation process, using thiophene-2-boronic acid pinacol ester and 2-bromothiazole as the starting materials, and then successively adding the N-bromo derivative with a succinimide skeleton and the aromatic boronic acid compound to obtain the final product, the preparation method is simple, the substrate applicability is wide, and the reaction process is mild.

[0040] As long as the reaction temperature and the addition ratio of each material are controlled in the above preparation method, the preparation process can be completed. The preparation conditions are relatively mild and the practicality is good.

[0041] In the application of the above organic molecular wire with adjustable π-π stacking effect, the organic molecular wire with adjustable π-π stacking effect is used to construct electronic components, such as supramolecular electronic devices. By changing the connection sites of the thiophene-thiazole unit of the electron donor-acceptor and other aromatic groups, the above organic molecular wire realizes the regulation of the π-π stacking effect through molecular isomerization, providing a theoretical basis and experimental foundation for constructing electronic components such as preparing supramolecular electronic devices by using weak intermolecular forces. Description of the Drawings

[0042] Figure 1 For the 1 1H-NMR spectrum of the compound corresponding to structural formula c;

[0043] Figure 2 For the 13 13C-NMR spectrum of the compound corresponding to structural formula c;

[0044] Figure 3 For the 1 1H-NMR spectrum of the compound corresponding to structural formula d;

[0045] Figure 4 For the 13 13C-NMR spectrum of the compound corresponding to structural formula d;

[0046] Figure 5 The H-NMR spectrum of the organic molecular wire corresponding to structural formula f; 1 H-NMR spectrum;

[0047] Figure 6 The H-NMR spectrum of the organic molecular wire corresponding to structural formula f; 13 C-NMR spectrum;

[0048] Figure 7 The H-NMR spectrum of the compound corresponding to structural formula g; 1 H-NMR spectrum;

[0049] Figure 8 The H-NMR spectrum of the compound corresponding to structural formula g; 13 C-NMR spectrum;

[0050] Figure 9 The H-NMR spectrum of the compound corresponding to structural formula h; 1 H-NMR spectrum;

[0051] Figure 10 The H-NMR spectrum of the compound corresponding to structural formula h; 13 C-NMR spectrum;

[0052] Figure 11 The H-NMR spectrum of the organic molecular wire corresponding to structural formula i; 1 H-NMR spectrum;

[0053] Figure 12 The H-NMR spectrum of the organic molecular wire corresponding to structural formula i; 13 C-NMR spectrum;

[0054] Figure 13 The H-NMR spectrum of the organic molecular wire corresponding to structural formula j; 1 H-NMR spectrum;

[0055] Figure 14 The H-NMR spectrum of the organic molecular wire corresponding to structural formula j; 13 C-NMR spectrum;

[0056] Figure 15 The single-molecule electronics characterization diagram of the organic molecular wire corresponding to structural formula f;

[0057] Figure 16 The single-molecule electronics characterization diagram of the organic molecular wire corresponding to structural formula i;

[0058] Figure 17 The single-molecule electronics characterization diagram of the organic molecular wire corresponding to structural formula j. Specific implementation manners

[0059] The present invention will be further described below in conjunction with specific embodiments.

[0060] Example 1

[0061] In this embodiment, the synthesis of the donor-acceptor polar center molecule f is carried out, and the specific reaction formula is expressed as follows:

[0062]

[0063] The following is a specific elaboration in combination with the corresponding steps.

[0064] (1) Synthesis of the intermediate with the chemical structure c:

[0065] Compound a (6.90 g, 32.75 mmol), compound b (4.50 g, 27.29 mmol), palladium acetate (75.0 mg, 0.71 mmol), 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene (0.41 g, 0.71 mmol) and potassium phosphate (17.50 g, 4.60 mmol) were added to a 250 mL two-necked flask containing toluene (60 mL) and pure water (20 mL). Under nitrogen protection, the mixture was stirred at 60 °C for 20 h. After the reaction was cooled to room temperature, it was extracted with dichloromethane. The organic phase was collected, dried with anhydrous magnesium sulfate, filtered and concentrated by rotary evaporation. Column chromatography was carried out using petroleum ether / dichloromethane (2 / 1) as the eluent to obtain 3.05 g of a colorless liquid. The yield was 67.5%.

[0066] The intermediate with the structure c was tested, and the results Figure 1 、 2 are shown as follows.

[0067] The characterization of the core performance parameters is as follows:

[0068] 1 H NMR (400 MHz, CDCl3, δ / ppm): 7.77 (d, J = 1.8 Hz, 1H), 7.53 - 7.52 (d, J = 3.8 Hz, 1H), 7.40 - 7.39 (d, J = 4.9 Hz, 1H), 7.26 - 7.25 (d, J = 1.7 Hz, 1H), 7.09 - 7.07 (t, J = 5.2 Hz, 1H).

[0069] 13 C NMR (400 MHz, CDCl3, δ / ppm): 162.0, 143.3, 137.4, 127.9, 127.7, 126.6, 118.2.

[0070] (2) Synthesis of the intermediate with the chemical structure d:

[0071] The intermediate c (1.00 g, 5.96 mmol) was dissolved in a 50 mL two-necked flask containing N,N-dimethylformamide (20 mL). After adding N-bromosuccinimide (1.00 g, 5.96 mmol) in the dark environment, it was stirred at room temperature for 8 h. After the reaction was completed, it was filtered and extracted with dichloromethane. The organic phase was collected and dried with anhydrous magnesium sulfate, filtered and concentrated by rotary evaporation. Column chromatography was carried out using petroleum ether / dichloromethane (2 / 1) as the eluent to obtain 0.50 g of white solid with a yield of 34.0%.

[0072] The intermediate with the structural formula d was tested, and the results Figure 3 、 4 are shown as follows.

[0073] The core performance parameters are characterized as follows:

[0074] 1 1H NMR (400 MHz, CDCl3, δ / ppm): 7.68 (s, 1H), 7.49 - 7.48 (dd, J = 3.7 Hz, 1.2 Hz, 1H), 7.46 - 7.44 (dd, J = 5.1 Hz, 1.2 Hz, 1H), 7.12 - 7.10 (dd, J = 5.1 Hz, 3.7 Hz, 1H).

[0075] 13 13C NMR (400 MHz, CDCl3, δ / ppm): 163.2, 144.4, 136.8, 128.2, 128.0, 126.9, 107.7.

[0076] (3) Synthesis of the organic molecular wire with the chemical structural formula f:

[0077] Compound d (0.35 g, 1.42 mmol), compound e (0.35 g, 2.84 mmol), tetrakis(triphenylphosphine)palladium (82.0 mg, 0.07 mmol) and cesium carbonate (0.93 g, 2.84 mmol) were added to a 50 mL two-necked flask containing 1,4-dioxane (30 mL) and pure water (3 mL). Under nitrogen protection, it was stirred at 100 °C for 24 h. After the reaction was cooled to room temperature, it was extracted with dichloromethane. The organic phase was collected and dried with anhydrous magnesium sulfate, filtered and concentrated by rotary evaporation. Column chromatography was carried out using petroleum ether / ethyl acetate (1 / 1) as the eluent to obtain 0.13 g of yellow solid with a yield of 38.5%.

[0078] The organic molecule with the structural formula f was tested, and the results Figure 5 、 6 are shown as follows.

[0079] The core performance parameters are characterized as follows:

[0080] 1 1H NMR (400 MHz, CDCl3, δ / ppm): 8.64 - 8.63 (d, J = 6.3 Hz, 2H), 8.09 (s, 1H), 7.57 - 7.56 (d, J = 3.7 Hz, 1H), 7.46 - 7.43 (t, J = 6.3 Hz, 3H), 7.14 - 7.09 (m, 1H).

[0081] 13 13C NMR (100 MHz, CDCl3, δ / ppm): 162.8, 150.7, 141.0, 138.6, 136.9, 135.5, 128.7, 128.2, 127.4, 120.5.

[0082] Example 2

[0083] In this example, the synthesis of donor - acceptor polar center molecules i and j was carried out, and the specific reaction formula is expressed as follows:

[0084]

[0085] The following is a specific elaboration in combination with the corresponding steps.

[0086] (1) Synthesis of the intermediate with chemical structure c:

[0087] Compound a (6.90 g, 32.75 mmol), compound b (4.50 g, 27.29 mmol), palladium acetate (75.0 mg, 0.71 mmol), 4,5 - bis(diphenylphosphino) - 9,9 - dimethyloxanthene (0.41 g, 0.71 mmol) and potassium phosphate (17.50 g, 4.60 mmol) were added to a 250 mL two - necked flask containing toluene (60 mL) and pure water (20 mL). Under nitrogen protection, the mixture was stirred at 60 °C for 20 h. After the reaction was cooled to room temperature, it was extracted with dichloromethane. The organic phase was collected, dried with anhydrous magnesium sulfate, filtered and concentrated by rotary evaporation. Column chromatography was carried out using petroleum ether / dichloromethane (2 / 1) as the eluent to obtain 3.05 g of a colorless liquid. The yield was 67.5%.

[0088] (2) Synthesis of the intermediate with chemical structure g:

[0089] The intermediate c (1.00 g, 5.96 mmol) was dissolved in a 50 mL two-necked flask containing N,N-dimethylformamide (20 mL). After adding N-bromosuccinimide (1.00 g, 5.96 mmol) in the dark, the mixture was stirred at room temperature for 8 h. After the reaction was completed, it was filtered and extracted with dichloromethane. The organic phase was collected, dried with anhydrous magnesium sulfate, filtered and concentrated by rotary evaporation. Column chromatography was carried out using petroleum ether / dichloromethane (2 / 1) as the eluent to obtain 0.48 g of a white solid with a yield of 33.6%.

[0090] The intermediate with the structural formula g was tested, and the results Figure 7 、 8 are shown as follows.

[0091] The core performance parameters are characterized as follows:

[0092] 1 H NMR (400 MHz, CDCl3, δ / ppm): 7.75 - 7.74 (d, J = 3.3 Hz, 1H), 7.26 - 7.24 (m, 2H), 7.04 - 7.03 (d, J = 3.9 Hz, 1H).

[0093] 13 C NMR (400 MHz, CDCl3, δ / ppm): 161.0, 143.4, 138.8, 130.8, 126.5, 118.4, 115.3.

[0094] (3) Synthesis of the intermediate with the chemical structural formula h:

[0095] The intermediate c (1.00 g, 5.96 mmol) was dissolved in a 50 mL two-necked flask containing N,N-dimethylformamide (20 mL). After adding N-bromosuccinimide (3.17 g, 17.90 mmol) in the dark, the mixture was stirred at room temperature for 12 h. After the reaction was completed, it was filtered and extracted with dichloromethane. The organic phase was collected, dried with anhydrous magnesium sulfate, filtered and concentrated by rotary evaporation. Column chromatography was carried out using petroleum ether / dichloromethane (1 / 1) as the eluent to obtain 0.85 g of a white solid with a yield of 41.2%.

[0096] The intermediate with the structural formula h was tested, and the results Figure 9 、 10 are shown as follows.

[0097] The core performance parameters are characterized as follows:

[0098] 11H NMR (400 MHz, CDCl3, δ / ppm): 7.62 (s, 1H), 7.18 - 7.17 (d, J = 3.9 Hz, 1H), 7.04 - 7.03 (d, J = 4.0 Hz, 1H).

[0099] 13 13C NMR (400 MHz, CDCl3, δ / ppm): 161.2, 144.5, 143.6, 139.0, 138.1, 133.8, 130.9, 126.7, 116.1, 108.1.

[0100] (4) Synthesis of the organic molecular wire with chemical structure i:

[0101] Compound g (0.35 g, 1.42 mmol), compound e (0.35 g, 2.84 mmol), tetrakis(triphenylphosphine)palladium (82.0 mg, 0.07 mmol) and cesium carbonate (0.93 g, 2.84 mmol) were added to a 50 mL two-necked flask containing 1,4-dioxane (30 mL) and pure water (3 mL). Under nitrogen protection, the mixture was stirred at 100 °C for 24 h. After the reaction was cooled to room temperature, it was extracted with dichloromethane. The organic phase was collected, dried over anhydrous magnesium sulfate, filtered and concentrated by rotary evaporation. Column chromatography was carried out using petroleum ether / ethyl acetate (1 / 1) as the eluent to obtain 0.14 g of a yellow solid with a yield of 39.8%.

[0102] Testing of the organic molecule with structure i gave the results Figure 11 、 12 as shown.

[0103] The core performance parameters are characterized as follows:

[0104] 1 1H NMR (400 MHz, CDCl3, δ / ppm): 8.64 - 8.62 (d, J = 5.6 Hz, 2H), 7.82 - 7.81 (d, J = 3.3 Hz, 1H), 7.53 - 7.52 (d, J = 3.9 Hz, 1H), 7.51 - 7.50 (d, J = 6.2 Hz, 2H), 7.49 - 7.48 (d, J = 3.9 Hz, 1H), 7.32 (d, J = 3.3 Hz, 1H).

[0105] 13 13C NMR (100 MHz, CDCl3, δ / ppm): 161.2, 150.6, 143.6, 142.8, 141.2, 138.7, 127.4, 126.0, 119.8, 118.9.

[0106] (5) Synthesis of the organic molecular wire with chemical structure j:

[0107] Compound h (0.50 g, 1.54 mmol), compound e (0.56 g, 4.62 mmol), tetrakis(triphenylphosphine)palladium (0.10 g, 0.09 mmol), and cesium carbonate (0.70 g, 2.15 mmol) were added to a 50 mL two-necked flask containing 1,4-dioxane (30 mL) and pure water (3 mL). Under nitrogen protection, the mixture was stirred at 100 °C for 24 h. After the reaction was cooled to room temperature, it was extracted with dichloromethane. The organic phase was collected, dried over anhydrous magnesium sulfate, filtered and concentrated by rotary evaporation. Column chromatography was carried out using petroleum ether / dichloromethane (1 / 1) as the eluent to obtain 65.0 mg of a yellow solid with a yield of 13.0%.

[0108] The organic molecule with the structural formula j was tested, and the results Figure 13 、 14 are shown as follows.

[0109] The core performance parameters are characterized as follows:

[0110] 1 H NMR (400 MHz, CDCl3, δ / ppm): 8.67 - 8.64 (m, 4H), 8.14 (s, 1H), 7.58 - 7.57 (d, J = 4.9 Hz, 1H), 7.52 - 7.51 (d, J = 2.5 Hz, 2H), 7.50 (s, 1H), 7.47 - 7.46 (d, J = 6.2 Hz, 2H).

[0111] 13 C NMR (400 MHz, CDCl3, δ / ppm): 162.0, 144.5, 143.6, 138.1, 133.7, 130.9, 126.7, 116.1, 108.1.

[0112] In the above Examples 1 and 2, after intermediate c was prepared, intermediate c reacted with N-bromosuccinimide to obtain two isomerized intermediates, namely intermediate d and intermediate g. The two intermediates were separated by column chromatography. In Example 1, intermediate d was used to continue the reaction with intermediate e to obtain the final product h; while in Example 2, intermediate g was used to continue the reaction with intermediate e at different molar ratios, and the final products i and j were respectively prepared.

[0113] To explore the regulation law of charge polarization caused by molecular isomerization on the π-π stacking effect of organic molecular wires, single-molecule electronics tests were carried out on the organic molecular wires corresponding to the structural formulas f, i, and j using the scanning tunneling microscope break junction technique (STM-BJ). The specific procedure is as follows:

[0114] (1) Preparation of the solution:

[0115] Dissolve the target molecule (structural formula f / i / j) in 1,2,4-trichlorobenzene to prepare a test solution with a concentration of 0.1 mM.

[0116] (2) Data acquisition:

[0117] Single-molecule conductance tests were performed on the target molecule under the same test conditions as the pure solvent (bias voltage 100 mV, sampling frequency 20 kHz). At least 3000 effective junction break curves were cumulatively collected for each molecular system to ensure statistical significance. The results are as Figure 15 shown.

[0118] (3) Single-molecule conductance analysis of structural formula f / i / j:

[0119] Figure 15 and 16 Figure 17 are the one-dimensional conductance statistical graphs and relative stretching distance step graphs of the organic molecular wires corresponding to structural formulas f, i, and j. After Gaussian fitting:

[0120] The conductance value of the organic molecular wire corresponding to structural formula f is G f = 10 -4.95 G0( Figure 15 (a) in), combined with the correction of the atomic rebound distance (0.5 nm) of the gold electrode, the total length Δz of its molecular junction is calculated to be 1.35 nm( Figure 15 (b) in).

[0121] The conductance value of the organic molecular wire corresponding to structural formula i is G i = 10 -5.10 G0( Figure 16 (c) in), combined with the correction of the atomic rebound distance (0.5 nm) of the gold electrode, the total length Δz of its molecular junction is calculated to be 1.25 nm( Figure 16 (d) in).

[0122] The conductance value of the organic molecular wire corresponding to structural formula j is G j = 10 -4.18 G0( Figure 17 (e) in), combined with the correction of the atomic rebound distance (0.5 nm) of the gold electrode, the total length Δz of its molecular junction is calculated to be 1.65 nm( Figure 17 (f) in).

[0123] The above characteristics of the organic molecular wire corresponding to Structure j are due to the asymmetric intramolecular polarization caused by its thiophenethiazole backbone, which has strong electron-withdrawing pyridine groups as anchoring groups at both ends. It is worth noting that both Structures f and i have terminal thiazole and thiophene units, which can effectively interact with the gold electrode as anchoring groups. Specifically, Structures f and i have similar overall sizes because they both have pyridine groups as anchoring groups and are connected by two five-membered aromatic rings. However, the electronic effects of these rings are different, resulting in changes in intramolecular charge polarization. Structure f adopts the acceptor-acceptor-donor (A-A-D) configuration, and compared with the acceptor-donor-acceptor (A-D-A) configuration of Structure i, Structure f exhibits a higher degree of intramolecular charge polarization.

[0124] Based on the above characteristics of the ultra-long molecular junction and the typical mechanical response of π-π stacking (>1.2 nm), we confirm that the above conductance signal originates from the π-π interaction of the above organic molecular wire. The low-conductance peaks of Structures f and i in the one-dimensional conductance statistical graph are caused by π-π stacking. Through the different conductance values, we found that the organic molecular wires corresponding to Structures f and i with similar conjugated backbones have different stacking effects, which reveals the regulation mechanism of molecular isomerization on π-π interaction.

[0125] The preparation method of the above molecular wire is simple and widely applicable. We regulate the π-π stacking effect of the molecular wire through the charge polarization caused by molecular isomerization. This method is universal and can be achieved by changing the structures of many organic molecules, providing a theoretical basis and experimental foundation for the preparation of organic molecular electronic devices based on supramolecular interactions.

Claims

1. An organic molecular wire with a regulable π-π stacking effect, characterized in that, The organic molecular wire with adjustable π-π stacking effect has a donor-acceptor polar center structure, and its general formula is expressed as: Wherein, R1 is any one of H, pyridyl, thiazolyl or thienyl, R2 is any one of H, pyridyl, thiazolyl or thienyl, and R1 and R2 are not both H at the same time.

2. A preparation method of an organic molecular wire with a regulable π-π stacking effect, characterized in that, The steps are as follows: Step 1, Thiophene-2-boronic acid pinacol ester reacts with 2-bromothiazole to obtain intermediate c. The structural formula of intermediate c is as follows: Step 2, Intermediate c reacts with an N-bromo derivative having a succinimide skeleton to obtain intermediate d. The structural formula of the N-bromo derivative with a succinimide skeleton is as follows: The structural formula of intermediate d is as follows: In the formula, X is Cl, Br or I. Step 3, Intermediate d reacts with an aromatic boronic acid compound to obtain the following final product. The structural formula of the aromatic boronic acid compound is as follows: R is any one of H, pyridyl, thiazolyl or thienyl, The structural formula of the final product is as follows: R1 is any one of H, pyridyl, thiazolyl or thienyl, R2 is any one of H, pyridyl, thiazolyl or thienyl, and R1 and R2 are not both H at the same time.

3. The preparation method of an organic molecular wire with a regulatable π-π stacking effect according to claim 2, wherein: In Step 1, the molar ratio of thiophene-2-boronic acid pinacol ester to 2-bromothiazole is 1.2 - 1.5:1 - 1.1, and the reaction temperature is 45 - 65 °C.

4. The preparation method of an organic molecular wire with adjustable π-π stacking effect according to claim 2, characterized in that: In Step 1, palladium acetate and 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene are also added as catalysts.

5. The preparation method of an organic molecular wire with a regulable π-π stacking effect according to claim 4, characterized in that: The added molar ratio of palladium acetate to 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene is 1:1 - 1.5, and the feeding molar ratio of thiophene-2-boronic acid pinacol ester to palladium acetate is 1:0.02 - 0.

025.

6. The preparation method of an organic molecular wire with adjustable π-π stacking effect according to claim 2, characterized in that: In Step 2, an N-bromo derivative having a succinimide skeleton is added in a dark environment, and the molar ratio of intermediate c to the N-bromo derivative having a succinimide skeleton is 1 - 1.2:1 - 1.

2.

7. The preparation method of an organic molecular wire with a regulatable π-π stacking effect according to claim 2, wherein: In Step 3, the molar ratio of intermediate d to the aromatic boronic acid compound is 1 - 1.2:2 - 2.4, and the reaction temperature is 100 - 120 °C.

8. The preparation method of an organic molecular wire with a regulable π-π stacking effect according to claim 2, characterized in that: In Step 3, tetrakis(triphenylphosphine)palladium is added as a catalyst, and the feeding molar ratio of intermediate d to tetrakis(triphenylphosphine)palladium is 1:0.02 - 0.

05.

9. A method for preparing an organic molecular wire with adjustable π-π stacking effect according to any one of claims 2 - 8, characterized in that The structural formula of the organic molecular wire with adjustable π-π stacking effect is Its reaction process is expressed as: Alternatively, the structural formula of the organic molecular wire with a tunable π-π stacking effect is The reaction process is expressed as:

10. Use of the organic molecular wire with adjustable π-π stacking effect according to claim 1, characterized in that: The organic molecular wire with adjustable π-π stacking effect is used to construct electronic components.

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