Method for synthesizing n-type conductive polymer poly (benzodifuran diketone)

Abstract

The invention belongs to the field of conducting polymers, and discloses a method for synthesizing an n-type conducting polymer poly (benzodifuran diketone) (PBFDO). The method comprises the following steps: in an inert atmosphere, dispersing benzodifuran diketone (BFDO), S8 and organic alkali in an organic solvent, then carrying out a heating reaction, and after the reaction is finished, pouring into a dialysis bag for dialysis to obtain the n-type conductive polymer PBFDO. The conductivity of the prepared n-type conductive polymer poly (benzodifuran diketone) (PBFDO) is 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(benzodifurandione) (PBFDO). Background Art

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

[0003] In 2022, Huang et al. synthesized for the first time a material with a conductivity of up to 2000 S cm -1 The n-type conductive polymer polybenzodifurandione (PBFDO) was first 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 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 a large molecular weight 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 raw material types 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 do not reach thousand-level conductivity.

[0004] Therefore, it is necessary to provide a method for synthesizing poly(benzodifurandione) 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 above-mentioned shortcomings and deficiencies of the prior art, the primary purpose of the present invention is to provide a method for synthesizing n-type conductive polymer poly(benzofurandione) (PBFDO), which successfully synthesizes a conductive polymer with a conductivity of up to 2300 S cm by using cheap sulfur as an oxidant and introducing some organic bases. -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(benzodifurandione) (PBFDO) prepared by the above method.

[0007] Another object of the present invention is to provide the application of the above 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, benzodifurandione (BFDO), S8 and an organic base 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.

[0011] Alternatively, in an inert atmosphere, benzodifurandione (BFDO) 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.

[0012] The organic base is at least one of 1,4-diazidebicyclo[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 polar aprotic solvents such as dimethyl sulfoxide (DMSO) and N,N-dimethylformamide (DMF); the organic solvent is preferably an ultra-dry organic solvent.

[0014] The molar ratio of benzodifurandione (BFDO), S8 (molar amount calculated based on a molecular weight of 32 g / mol) and the 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 used satisfies: the concentration of benzodifurandione is 5-10 mg / ml, preferably 10 mg / ml.

[0016] The heating reaction refers to heating to 25-120°C for 1-6 hours, preferably at 100°C for 6 hours.

[0017] The molecular weight cutoff of the dialysis bag is 10 kDa, the dialysis time is more than 72 hours, 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 24 hours.

[0018] An n-type conductive polymer poly(benzodifurandione) (PBFDO) prepared by the above method has a conductivity of up to 2300 S cm -1 .

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

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

[0021] (1) The present invention provides a new route for synthesizing PBFDO, which can provide an electrical conductivity of up to 2,000, thereby promoting the development and utilization of the material.

[0022] (2) The raw materials of the present invention are low-toxic, low-cost, and widely available. Different organic bases can be used to obtain good high-conductivity polymers.

[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 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 state.

[0026] Figure 3 As raw material, benzodifurandione (BFDO) and the n-type conjugated polymer ( Figure 3 PBFDO (S)) and the n-type conjugated polymer ( 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 by 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 is further described in detail below in conjunction with the examples and drawings, but the embodiments of the present invention are not limited thereto. If specific conditions are not specified in the examples, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0032] Unless otherwise specified, the 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 ... The CAS number of 1,8-diazabicyclo[5.4.0]undec-7-ene (TBD) is 5807-14-7; the CAS number of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) is 6674-22-2; the CAS number of triethylamine is 121-44-8; the CAS number of 4-dimethylaminopyridine (DMAP) is 1122-58-3; the CAS number of quinuclidine is 100-76-5; the CAS number of dimethyl sulfoxide is 67-68-5. All of them are common commercial chemical raw materials.

[0033] Example 1

[0034] In an argon atmosphere glove box, add 5 ml of ultra-dry dimethyl sulfoxide (DMSO) to a sample bottle containing benzodifurandione (50 mg, 1 eq) and S8 (8.4211 mg, 1 eq), heat to 100 ° C, react for 6 hours, and then pour the solution into a dialysis bag with a molecular weight cutoff of 10 kDa for dialysis. Replace the DMSO solvent every 24 hours and dialyze for 72 hours. Take 100 μL of the solution and drop it on the pre-treated substrate, anneal at 80 ° C for 90 minutes, and then use the LakeShore 8400s instrument to perform the Hall test. The results are shown in Table 1 below. The conductivity is 649.9 S cm -1 .

[0035]

[0036] Table 1

[0037]

[0038] Example 2

[0039] In an argon atmosphere glove box, add 5 ml of ultra-dry dimethyl sulfoxide (DMSO) to a sample bottle containing benzodifurandione (50 mg, 1 eq), S8 (8.4211 mg, 1 eq), 1,4-diazabicyclo[2.2.2]octane (DABCO) (2.9474 mg, 0.1 eq), heat to 100 ° C, react for 6 hours, and then pour the solution into a dialysis bag with a molecular weight cutoff of 10 kDa for dialysis. Replace the DMSO solvent every 24 hours and dialyze for 72 hours. Take 100 μL of the solution and drop it on the pre-treated substrate, anneal at 80 ° C for 90 minutes, and then use the LakeShore 8400s instrument to perform the Hall test. The results are shown in Table 2. The conductivity is 2325.04 S cm -1 .

[0040]

[0041] Table 2

[0042]

[0043] Example 3

[0044] In an argon atmosphere glove box, add 5 ml of ultra-dry dimethyl sulfoxide (DMSO) to a sample bottle containing benzodifurandione (50 mg, 1 eq), S8 (8.4211 mg, 1 eq), 1,4-diazabicyclo [2.2.2] octane (DABCO) (2.9474 mg, 0.1 eq), heat to 100 ° C, react for 2, 4, and 6 hours respectively, then pour the solution into a dialysis bag with a molecular weight cutoff of 10 kDa for dialysis, replace the DMSO solvent every 24 hours, and dialyze for 72 hours. Take 100 μL of the solution and drop it on the pre-treated substrate, anneal at 80 ° C for 90 minutes, and then use the LakeShore 8400s instrument to perform the Hall test. The results are shown in Table 3 below. It can be seen from Table 3 that the optimal reaction time is 6 hours.

[0045]

[0046] Table 3

[0047]

[0048] Example 4

[0049] On the basis of Example 2, DABCO was used as a 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] On the basis of 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 hours. The specific reaction conditions and results are shown in Table 5 below. It can be seen from Table 5 that the best organic base is DABCO.

[0055]

[0056] Table 5

[0057]

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

[0059] Figure 3 As raw material, benzodifurandione (BFDO) and the n-type conjugated polymer ( Figure 3 PBFDO (S)) and the n-type conjugated polymer ( 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 DMF. The mixture was reacted at 100 °C for 6 hours. After cooling to room temperature, the mixture was precipitated with methanol, and then filtered to collect the precipitate. The precipitate was then extracted with acetone, tetrahydrofuran, and DMF in turn. 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 diagram of the model oligomer synthesized after adding the end-capping agent 6-bromo-1-(2-octyldodecyl)indole-2,3-dione shows that the oligomers are composed of one end-capped oligomers such as n=2, n=3, n=4, and n=5. The measured molecular weights of the polymers + Na are 1072, 1258, 1444, and 1630, respectively, and the errors are within 1% compared with the theoretical values. In addition, the mass of each group of peaks differs by one repeating unit (186), which proves the successful polymerization of the reaction.

[0061] Figure 5 This is the thermogravimetric diagram of the polymer synthesized by 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 a thermogravimetric graph of the n-type conjugated polymer synthesized by 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 (relative to Ag / AgCl) was observed in PBFDO, indicating its extremely deep initial 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 equivalent replacement methods and are included in the protection scope 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, 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. 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(benzodifurandione) according to claim 1, characterized in that: 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; preferably 1,4-diazidebicyclo[2.2.2]octane.

3. The method for synthesizing an n-type conductive polymer poly(benzodifurandione) according to claim 1, characterized in that: The organic solvent is at least one of dimethyl sulfoxide and N,N-dimethylformamide; preferably dimethyl sulfoxide.

4. The method for synthesizing an n-type conductive polymer poly(benzodifurandione) according to claim 1, characterized in that: The molar ratio of benzodifurandione, S8 and organic base is 1:(0.5-1):(0-0.2), preferably 1:1:0.

1.

5. The method for synthesizing an n-type conductive polymer poly(benzodifurandione) according to claim 1, characterized in that: The amount of the organic solvent used satisfies: the concentration of benzodifurandione is 5-10 mg / ml, preferably 10 mg / ml.

6. The method for synthesizing an n-type conductive polymer poly(benzodifurandione) according to claim 1, characterized in that: The heating reaction refers to heating to 25-120°C for 1-6 hours, preferably at 100°C for 6 hours.

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

8. An n-type conductive polymer poly(benzodifurandione) prepared by the method according to any one of claims 1 to 7.

9. The n-type conductive polymer poly(benzodifurandione) according to claim 8, characterized in that Its conductivity is ≥2300S cm -1 , preferably 2325S cm -1 .

10. Use of the n-type conductive polymer poly(benzodifurandione) according to claim 8 or 9 in organic light emitting diodes, organic field effect transistors, organic electrochemical transistors and organic thermoelectrics.

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