A method of synthesizing an n-type conductive polymer, poly(benzodifuran-diketone)

Abstract

The application belongs to the field of conductive polymers, and discloses a method for synthesizing n-type conductive polymer poly(benzodifuran dione) (PBFDO). The method comprises the following steps: dispersing benzodifuran dione (BFDO), S8 and an organic base in an organic solvent in an inert atmosphere, then heating the reaction, and then pouring the reaction product into a dialysis bag for dialysis after the reaction is completed, so as to obtain the n-type conductive polymer PBFDO. The n-type conductive polymer poly(benzodifuran dione) (PBFDO) prepared has a conductivity as high as 2300 S cm ‑1 .

Description

Technical Field

[0001] The invention belongs to the field of conductive polymers, and in particular relates to a method for synthesizing n-type conductive polymer poly(benzofurandione) (PBFDO). Background Art

[0002] Conductive polymers have the advantages of low cost, light weight, and good solution processability, and are widely used in various organic electronic devices such as organic light-emitting diodes, organic field-effect transistors, organic electrochemical transistors, and organic thermoelectrics. Depending on the type of carrier, they can be divided into p-type (hole transport) and n-type (electron transport). Among them, the p-type organic conductive material poly (3,4-ethylenedioxythiophene) / polystyrene sulfonate (PEDOT:PSS) has been successfully commercialized, and after secondary doping, the conductivity exceeds 1000 S cm -1 N-type polymers are key components in realizing various organic optoelectronic devices and complementary circuits. Therefore, synthesizing high-performance n-type conducting polymers that match p-type is challenging. In recent years, significant progress has been made in the development of high-performance n-type conducting polymers, and research on n-type conducting polymers is increasing.

[0003] In 2022, Huang et al. first synthesized a material with a conductivity of up to 2000 S cm -1 The n-type conductive polymer polybenzofurandione (PBFDO) was discovered. Subsequently, research on PBFDO has emerged in an endless stream and has become a hot topic in current research. PBFDO is a side chain-free n-type highly conductive polymer material with excellent electrical conductivity and optical transparency. Its discovery is considered a major breakthrough in the field of organic semiconductors. They were synthesized using 3,7-dihydrobenzo[1,2-b:4,5-b′]difuran-2,6-dione (H-BFDO) as a precursor in the presence of a benzoquinone oxidant. Figure 1 (a)) This reaction combines oxidative polymerization and in-situ reduction doping, greatly improving the doping efficiency, with excellent stability and solution processability, and does not require additional side chains or surfactants (Nature 2022, 611, 271-277.). However, the additives used in this method have large molecular weights and require a large amount. In 2023, Mei et al. reported a cascade reaction catalyzed by copper in air to synthesize PBFDO ( Figure 1 (b)), which includes oxidative polymerization and reductive doping in one pot (J.Am.Chem.Soc.2023,145,3706-3715.). This method not only requires a large amount of raw materials, but also has limited types of raw materials and can only be synthesized within a limited range. In 2024, Yang et al. proposed a method that can be directly polymerized in water ( Figure 1(c)) to obtain a highly conductive, water-processable n-type conjugated polymer, poly[(2,2′-(2,5-dihydroxy-1,4phenylene)diacetic acid)-stat-3,7-dihydrobenzo[1,2-b:4,5-b′]difuran-2,6-dione](PDADF), with a conductivity of up to 66 S cm -1 , which ranks among the best n-type polymers processed using green solvents (J.Am.Chem.Soc.2024,146,15860-15868.). Although it can be synthesized in green solvents, the synthesized conductive polymers cannot reach thousand-level conductivity.

[0004] Therefore, there is a need to provide a method for synthesizing poly(benzofurandione) with low-toxicity and low-cost raw materials, a wide variety of raw materials, and high electrical conductivity. Summary of the Invention

[0005] In order to overcome the shortcomings and deficiencies of the above-mentioned prior art, the primary purpose of the present invention is to provide a method for synthesizing n-type conductive polymer poly(benzofurandione) (PBFDO). By using inexpensive elemental sulfur as an oxidant and introducing some organic bases, a conductive polymer with a conductivity of up to 2300 S cm is successfully synthesized. -1 PBFDO makes up for the low conductivity of most n-type organic conductive polymers and can achieve high-performance conductivity matching that of p-type, providing a new synthesis method and idea for the development of this material.

[0006] Another object of the present invention is to provide an n-type conductive polymer poly(benzofurandione) (PBFDO) prepared by the above method.

[0007] Another object of the present invention is to provide applications of the n-type conductive polymer poly(benzofurandione) (PBFDO) in various organic electronic devices such as organic light emitting diodes, organic field effect transistors, organic electrochemical transistors, and organic thermoelectrics.

[0008] The purpose of the present invention is achieved through the following solutions:

[0009] A method for synthesizing an n-type conductive polymer poly(benzofurandione) (PBFDO) comprises the following steps:

[0010] In an inert atmosphere, benzofurandione (BFDO), S8 and an organic base are dispersed in an organic solvent, then heated to react. After the reaction is completed, the mixture is poured into a dialysis bag for dialysis to obtain an n-type conductive polymer PBFDO.

[0011] Or, in an inert atmosphere, disperse benzodifuran dione (BFDO) and S8 in an organic solvent, then heat the reaction, after the reaction is completed, pour into a dialysis bag for dialysis, to obtain an n-type conductive polymer PBFDO.

[0012] The organic base is at least one of 1,4-diazidobicyclo[2.2.2]octane (DABCO), pyridine, 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD), 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), Et3N, 4-dimethylaminopyridine (DMAP), and quinuclidine.

[0013] The organic solvent is at least one of dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), and other polar aprotic solvents; the organic solvent is preferably super-dry organic solvent.

[0014] The molar ratio of benzodifuran dione (BFDO), S8 (calculated by molar mass 32 g / mol), and organic base is any ratio, preferably 1:(0.5-1):(0-0.2), more preferably 1:1:0.1.

[0015] The amount of the organic solvent satisfies that the concentration of benzodifuran dione is 5-10 mg / ml, preferably 10 mg / ml.

[0016] The heating reaction refers to heating to 25-120℃ for 1-6h, preferably 100℃ for 6h.

[0017] The dialysis bag has a molecular weight cut-off of 10 kDa, the dialysis time is more than 72h, the dialysis solvent corresponds to the organic solvent in the reaction, that is, it is also at least one of DMSO and DMF, and the solvent is replaced every 24h.

[0018] An n-type conductive polymer poly(benzodifuran dione) (PBFDO) prepared by the above method, which has an electrical conductivity as high as 2300 S cm -1 .

[0019] The n-type conductive polymer poly(benzodifuran dione) (PBFDO) is applied in various organic electronic devices such as organic light-emitting diodes, organic field-effect transistors, organic electrochemical transistors, and organic thermoelectric devices.

[0020] Compared with the prior art, the present application has the following advantages and beneficial effects:

[0021] (1) The present application provides a new route for synthesizing PBFDO, which can provide an electrical conductivity as high as two thousand, promoting the development and utilization of the material.

[0022] (2) The raw materials of the present invention are low-toxic, cheap, and widely available, and good high-conductivity polymers can be obtained by using different organic bases.

[0023] (3) The synthesis steps are simple and efficient, the operation is easy, the reaction time is short, and the post-processing is simple. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Schematic diagram of the synthesis of n-type highly conductive polymer materials in the prior art, including (a) the schematic diagram of the synthesis of PBFDO reported by Huang et al.; (b) the schematic diagram of the BDF oxidative polymerization and PBDF reductive doping reported by Mei et al.; (c) the schematic diagram of the synthesis of PDADF using TMQ-PA catalyst by Yang et al.

[0025] Figure 2 This is the ultraviolet absorption spectrum of the polymer synthesized using DABCO in Example 2 in solution.

[0026] Figure 3 As raw material, benzofurandione (BFDO), pure S8 was used in Example 1 without adding alkali to synthesize n-type conjugated polymer ( Figure 3 PBFDO (S) in the above text and the n-type conjugated polymer synthesized by using pure S8 and base DABCO in Example 2 ( Figure 3 Infrared spectrum of PBFDO (DABCO).

[0027] Figure 4 This is the MALDI-TOF-MS spectrum of the model oligomer synthesized after adding the capping agent 6-bromo-1-(2-octyldodecyl)indole-2,3-dione.

[0028] Figure 5 This is the thermogravimetric diagram of the polymer synthesized using pure S8 in Example 1 after extraction.

[0029] Figure 6 This is the thermogravimetric diagram of the n-type conjugated polymer synthesized using DABCO in Example 2 after extraction.

[0030] Figure 7 This is the cyclic voltammogram of the n-type conjugated polymer synthesized using DABCO in Example 2. DETAILED DESCRIPTION

[0031] The present invention will be described in further detail below with reference to the Examples and accompanying drawings, but the embodiments of the present invention are not limited thereto. Where specific conditions are not specified in the Examples, conventional conditions or conditions recommended by the manufacturer were followed. Reagents or instruments used, where the manufacturer is not specified, are commercially available conventional products.

[0032] Unless otherwise specified, all reagents used in the examples can be purchased from the market. The raw material benzodifurandione is 3,7-dihydrobenzo[1,2-b:4,5-b']difuran-2,6-dione, CAS No. 30272-74-3; the CAS No. of high-purity sulfur is 7704-34-9; the CAS No. of 1,4-diazidebicyclo[2.2.2]octane (DABCO) is 280-57-9; the CAS No. of pyridine is 110-86-1; the CAS No. of 1,5,7-triazabicyclo[4.4.0]decane is 1,4-dihydrobenzo[1,2-b:4,5-b']difuran-2,6-dione is 3,7-dihydrobenzo[1,2-b:4,5-b']difuran-2,6-dione is 3,7-dihydrobenzo[1,2-b:4,5-b']difuran-2,6-dione The CAS number for 1,5-dimethylbenzene (TBD) is 5807-14-7; the CAS number for 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) is 6674-22-2; the CAS number for triethylamine is 121-44-8; the CAS number for 4-dimethylaminopyridine (DMAP) is 1122-58-3; the CAS number for quinuclidine is 100-76-5; and the CAS number for dimethyl sulfoxide is 67-68-5. All of these are common commercially available chemical raw materials.

[0033] Example 1

[0034] In an argon-filled glove box, 5 ml of ultra-dry dimethyl sulfoxide (DMSO) was added to a sample vial containing benzodifurandione (50 mg, 1 eq) and S8 (8.4211 mg, 1 eq). The solution was heated to 100°C and allowed to react for 6 h. The solution was then dialyzed into a 10 kDa molecular weight cutoff dialysis bag, with the DMSO solvent replaced every 24 h for 72 h. A 100 μL droplet of the solution was placed on a pre-treated substrate, annealed at 80°C for 90 min, and then subjected to Hall effect testing using a LakeShore 8400s instrument. The results are shown in Table 1 below, and the measured conductivity was 649.9 S cm -1 .

[0035]

[0036] Table 1

[0037]

[0038] Example 2

[0039] In an argon-filled glove box, 5 ml of ultra-dry dimethyl sulfoxide (DMSO) was added to a sample vial containing benzodifurandione (50 mg, 1 eq), S8 (8.4211 mg, 1 eq), and 1,4-diazabicyclo[2.2.2]octane (DABCO) (2.9474 mg, 0.1 eq). The solution was heated to 100°C and allowed to react for 6 h. The solution was then dialyzed into a 10 kDa dialysis bag, with the DMSO solvent replaced every 24 h for 72 h. A 100 μL droplet of the solution was placed on a pretreated substrate and annealed at 80°C for 90 min. Hall effect measurements were then performed using a LakeShore 8400s instrument. The results are shown in Table 2, and the measured conductivity was 2325.04 S cm -1 .

[0040]

[0041] Table 2

[0042]

[0043] Example 3

[0044] In an argon-filled glove box, 5 mL of ultra-dry dimethyl sulfoxide (DMSO) was added to a sample vial containing benzodifurandione (50 mg, 1 eq), S8 (8.4211 mg, 1 eq), and 1,4-diazabicyclo[2.2.2]octane (DABCO) (2.9474 mg, 0.1 eq). The mixture was heated to 100°C and reacted for 2, 4, and 6 hours, respectively. The solution was then dialyzed into a 10 kDa dialysis bag, with the DMSO solvent replaced every 24 hours for 72 hours. A 100 μL droplet was then placed on a pretreated substrate and annealed at 80°C for 90 minutes. Hall effect measurements were then performed using a LakeShore 8400s instrument. The results are shown in Table 3 below, which shows that the optimal reaction time was 6 hours.

[0045]

[0046] Table 3

[0047]

[0048] Example 4

[0049] On the basis of Example 2, DABCO was used as the catalyst, the ratio of S8: alkali and the feed concentration were changed, and other conditions remained unchanged. The specific reaction conditions and results are shown in Table 4 below. It can be seen from Table 4 that the optimal feed ratio is 1:1:0.1, and the feed concentration (i.e., benzodifurandione concentration) is 10 mg / ml.

[0050]

[0051] Table 4

[0052]

[0053] Example 5

[0054] Based on Example 4, different bases were used at a feed ratio of 1:1:0.1 and a feed concentration of 10 mg / ml, and the reaction was carried out at 100°C for 6 h. The specific reaction conditions and results are shown in Table 5 below. As can be seen from Table 5, the optimal organic base is DABCO.

[0055]

[0056] Table 5

[0057]

[0058] Figure 2 This is the UV absorption spectrum of the polymer synthesized using DABCO in solution in Example 2. As can be seen from the figure, PBFDO exhibits strong infrared absorption greater than 1600 nm, indicating the presence of strong polarons / bipolarons along the conjugated backbone.

[0059] Figure 3 As raw material, benzofurandione (BFDO), pure S8 was used in Example 1 without adding alkali to synthesize n-type conjugated polymer ( Figure 3 PBFDO (S) in the above text and the n-type conjugated polymer synthesized by using pure S8 and base DABCO in Example 2 ( Figure 3 Compared with the raw material, 1681cm -1 The weaker peak can be attributed to the peak of C=C double bond, which preliminarily indicates that we have synthesized the polymer.

[0060] Under nitrogen, 3,7-dihydrobenzo[1,2b:4,5-B']difuran-2,6-dione (1.520 g, 8 mmol), S8 (0.256 g, 8 mmol), DABCO (89.6 mg, 0.8 mmol), and end-capping agent 6-bromo-1-(2-octyldodecyl)indole-2,3-dione (4.0421 g, 8 mmol) were dissolved in 200 ml of DMF. The mixture was reacted at 100 ° C for 6 hours. After cooling to room temperature, methanol was added for dropwise precipitation. The precipitate was then collected by filtration and then extracted with acetone, tetrahydrofuran and DMF in sequence. The resulting solution was collected and concentrated. The acetone phase was subjected to matrix-assisted laser desorption ionization-time of flight-mass spectrometry (MALDI-TOF-MS) test. Figure 4The MALDI-TOF-MS spectra of model oligomers synthesized after adding the end-capping agent 6-bromo-1-(2-octyldodecyl)indole-2,3-dione show oligomers with one end-capped with n=2, n=3, n=4, and n=5, respectively. The measured molecular weights of the polymers (+Na) were 1072, 1258, 1444, and 1630, respectively, all within 1% of the theoretical values. Furthermore, the mass difference of one repeating unit (186) was observed for each peak group, confirming the successful polymerization of the reaction.

[0061] Figure 5 This is the thermogravimetric diagram of the polymer synthesized using pure S8 in Example 1 after extraction. The thermogravimetric analysis results show that the synthesized polymer has high thermal stability, and the temperature at which the sample reaches 5% weight loss is 295°C.

[0062] Figure 6 This is the thermogravimetric diagram of the n-type conjugated polymer synthesized using DABCO after extraction in Example 2. The thermogravimetric analysis results show that the synthesized polymer has high thermal stability, and the temperature at which the sample reaches 5% weight loss is 310°C.

[0063] Figure 7 : is the cyclic voltammogram of the n-type conjugated polymer synthesized using DABCO in Example 2. A reduction peak of about 0.85 V (vs. Ag / AgCl) was observed in PBFDO, indicating an extremely deep onset reduction energy level at -5.25 eV.

[0064] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A method for synthesizing an n-type conductive polymer poly(benzofurandione), characterized in that The following steps are involved: In an inert atmosphere, benzodifurandione, S8 and an organic base are dispersed in an organic solvent, then heated for reaction. After the reaction is completed, the mixture is poured into a dialysis bag for dialysis to obtain an n-type conductive polymer PBFDO. Alternatively, in an inert atmosphere, benzodifurandione and S8 are dispersed in an organic solvent, and then heated to react. After the reaction is completed, the mixture is poured into a dialysis bag for dialysis to obtain an n-type conductive polymer PBFDO.

2. The method for synthesizing an n-type conductive polymer poly(benzofurandione) according to claim 1, wherein: The organic base is at least one of 1,4-diazidebicyclo[2.2.2]octane, pyridine, 1,5,7-triazabicyclo[4.4.0]dec-5-ene, 1,8-diazabicyclo[5.4.0]undec-7-ene, Et3N, 4-dimethylaminopyridine and quinuclidine.

3. The method for synthesizing an n-type conductive polymer poly(benzofurandione) according to claim 2, wherein: The organic base is 1,4-diazidebicyclo[2.2.2]octane.

4. The method for synthesizing an n-type conductive polymer poly(benzofurandione) according to claim 1, wherein: The organic solvent is at least one of dimethyl sulfoxide and N,N-dimethylformamide.

5. The method for synthesizing an n-type conductive polymer poly(benzofurandione) according to claim 1, wherein: The organic solvent is dimethyl sulfoxide.

6. The method for synthesizing an n-type conductive polymer poly(benzofurandione) according to claim 1, wherein: The molar ratio of the benzodifurandione, S8 and the organic base is 1: (0.5-1): (0-0.2).

7. The method for synthesizing an n-type conductive polymer poly(benzofurandione) according to claim 6, wherein: The molar ratio of the benzodifurandione, S8 and the organic base is 1:1:0.

1.

8. The method for synthesizing an n-type conductive polymer poly(benzofurandione) according to claim 1, wherein: The amount of the organic solvent is such that the concentration of benzodifurandione is 5-10 mg / ml.

9. The method for synthesizing an n-type conductive polymer poly(benzofurandione) according to claim 8, wherein: The amount of the organic solvent is such that the concentration of benzodifurandione is 10 mg / ml.

10. The method for synthesizing an n-type conductive polymer poly(benzofurandione) according to claim 1, wherein: The heating reaction refers to heating to 25-120° C. for 1-6 hours.

11. The method for synthesizing an n-type conductive polymer poly(benzofurandione) according to claim 10, wherein: The heating reaction refers to heating to 100° C. for 6 hours.

12. The method for synthesizing an n-type conductive polymer poly(benzofurandione) according to claim 1, wherein: The molecular weight cut-off of the dialysis bag is 10 kDa, the dialysis time is more than 72 h, and the dialysis solvent is at least one of DMSO and DMF.

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