Iron-catalyzed hydrocarbon activation method for synthesizing organic polymer containing thiophene structure

Abstract

Metallic iron is used as a catalyst, the synthesis method is a hydrocarbon activation coupling method, the end capping of a product is not needed, and the method comprises the following steps: mixing a monomer with a ligand, then adding ferric trichloride hydrate (0.067 M) dissolved in THF (tetrahydrofuran), and carrying out a reaction for 1-2 hours to obtain the organic polymer containing the thiophene structure. Slowly dropwise adding a toluene solution (1.6 M) of trimethylaluminum, and finally adding an oxidizing agent diethyl oxalate to obtain a mixed solution; heating and stirring the mixed solution, adding hydrochloric acid and THF in sequence after 22 hours to dilute the reaction solution, then centrifuging the diluted reaction solution for 10 minutes under the condition of 10000 rpm, and collecting the centrifuged liquid. The invention relates to the technical field of organic polymer synthesis, the used catalyst and reactants are cheap and easily available compounds, the raw materials do not need to be halogenated, the cost is low, and the preparation method is simple and convenient. The cost of modification such as boron esterification or silicon esterification is far lower than that of a palladium catalysis method, ferric salt is easier to remove than palladium salt, the method has few steps, and finally, a polymer with higher purity can be obtained.

Description

Technical Field

[0001] The invention relates to the technical field of organic polymer synthesis, in particular to an iron-catalyzed carbon-hydrogen activation method for synthesizing an organic polymer containing a thiophene structure. Background Art

[0002] Organic polymer semiconductors are widely used as optoelectronic materials in various fields such as solar cells and organic light-emitting diodes. The prior art uses a palladium-catalyzed coupling synthesis method, which has four obvious defects: First, the method uses an expensive palladium catalyst and is costly. Second, an equivalent amount of byproduct MX is produced, which has poor atom economy and is prone to environmental pollution. Third, the M and X at the ends of the generated products require complex and cumbersome additional steps to cap. Fourth, the palladium catalyst, the byproduct MX, and the impurities mixed in the capping step will remain in the final product and are difficult to remove, affecting the photovoltaic performance of the polymer semiconductor. Summary of the invention

[0003] In view of the shortcomings of the prior art, the present invention provides an iron-catalyzed hydrocarbon activation method for synthesizing organic polymers containing thiophene structures, which solves the problems of the prior art in synthesizing organic polymers containing thiophene structures, such as high cost, easy environmental pollution, and the need for complex and cumbersome additional steps for end-capping and difficulty in removing impurities.

[0004] To achieve the above object, the present invention is implemented by the following technical scheme: an iron-catalyzed carbon-hydrogen activation method is used to synthesize an organic polymer containing a thiophene structure, characterized in that metallic iron is used as a catalyst, the synthesis method is a carbon-hydrogen activation coupling method, and the product does not need to be capped, wherein the method comprises:

[0005] S1: After the monomer and the ligand are mixed, hydrated ferric chloride (0.067 M) dissolved in THF is added, and then a toluene solution of trimethylaluminum (1.6 M) is slowly added dropwise, and finally an oxidant diethyl oxalate is added to obtain a mixed solution;

[0006] S2: The mixed solution is heated and stirred. After 22 hours, hydrochloric acid and THF are added successively to dilute the reaction solution. The diluted reaction solution is then centrifuged at 10,000 rpm for 10 minutes. The liquid after centrifugation is collected, and the solvent is removed by rotary evaporation. The obtained solid is redissolved in dichloromethane, and the insoluble solid is removed by filtration. The solid is placed at -20°C for one week for sedimentation. The precipitated solid is then collected by filtration, washed with water, and dissolved and precipitated again in dichloromethane to obtain the target polymer.

[0007] Preferably, the monomer is a compound with thiophene structures at both ends, and the THF solution of ferric chloride and the toluene solution of trimethylaluminum can also be a combined solution of iron salt+ligand+base+oxidant.

[0008] Beneficial Effects

[0009] The present invention provides an iron-catalyzed carbon-hydrogen activation method for synthesizing an organic polymer containing a thiophene structure, which has the following characteristics:

[0010] Beneficial effects:

[0011] 1. The catalyst and reactants used in this method (including the post-treatment step) are cheap and readily available compounds, and the raw materials do not need to be modified by halogenation, boron esterification or silicon esterification, and the cost is much lower than the palladium catalysis method.

[0012] 2. The by-products generated in this method are all low-toxic and easy-to-handle compounds with little harm to the environment.

[0013] 3. The generated product ends with hydrogen atoms, and no additional capping is required, which can completely avoid the risk of impurities mixed into the capping step or incompletely capped products.

[0014] 4. Iron salts are easier to remove than palladium salts, and this method has fewer steps and generates fewer by-products, so a higher purity polymer can be obtained in the end.

[0015] 5. The degree of polymerization can be controlled through simple operational adjustments. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is the current mainstream method for synthesizing organic polymer semiconductors containing thiophene structures.

[0017] Figure 2 The invention provides a method for synthesizing an organic polymer semiconductor containing a thiophene structure.

[0018] Figure 3 This is an example of a specific solution of the present invention. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] See also Figure 1-3 The present invention provides a technical solution: an iron-catalyzed carbon-hydrogen activation method for synthesizing an organic polymer containing a thiophene structure, characterized in that metallic iron is used as a catalyst, the synthesis method is a carbon-hydrogen activation coupling method, and the product does not need to be capped, wherein the method comprises:

[0021] S1: After the monomer and the ligand are mixed, hydrated ferric chloride (0.067 M) dissolved in THF is added, and then a toluene solution of trimethylaluminum (1.6 M) is slowly added dropwise, and finally an oxidant diethyl oxalate is added to obtain a mixed solution;

[0022] S2: The mixed solution is heated and stirred. After 22 hours, hydrochloric acid and THF are added successively to dilute the reaction solution. The diluted reaction solution is then centrifuged at 10,000 rpm for 10 minutes. The liquid after centrifugation is collected, and the solvent is removed by rotary evaporation. The obtained solid is redissolved in dichloromethane, and the insoluble solid is removed by filtration. The solid is placed at -20°C for one week for precipitation. The precipitated solid is then collected by filtration, washed with water, and dissolved and precipitated again in dichloromethane to obtain the target polymer.

[0023] Trimethylaluminum is a base, and other bases may also be used. Different bases are suitable for different substrates.

[0024] Diethyl oxalate is an oxidizing agent, and other oxidizing agents are also suitable;

[0025] The iron-catalyzed carbon-hydrogen activation method is used to synthesize organic polymer semiconductors. The iron catalyst is used to activate the carbon-hydrogenation of the thiophene structure. The target polymer is synthesized using thiophene compounds modified by halogenation, boron esterification or silicon esterification as monomers. The target product can be produced on a scale of more than 10g, and the degree of polymerization can be well controlled within the range of 5-400. At the same time, all metal residues can be reduced to less than 10ppm, especially palladium residues can be reduced to less than 1ppb;

[0026] For monomers with other structures or polymerization of different monomers, other types of iron sources, bases, oxidants, ligands and cleaning methods can be used to achieve the best yield and purity. The same principle can be used to synthesize thiophene organic polymers using iron catalysts.

[0027] Furthermore, the monomer is a compound with thiophene structures at both ends, and the THF solution of ferric chloride and the toluene solution of trimethylaluminum can also be a combined solution of iron salt+ligand+base+oxidant.

[0028] By those skilled in the art, the components in this case are connected in sequence. The specific connection and operation sequence should refer to the following working principle. The detailed connection means are well-known technologies in the field. The following mainly introduces the working principle and process.

[0029] Embodiment: First, the monomer and the ligand are mixed, and then hydrated ferric chloride (0.067M) dissolved in THF is added, and then a toluene solution of trimethylaluminum (1.6M) is slowly added dropwise, and finally the oxidant diethyl oxalate is added to obtain a mixed solution; the mixed solution is heated and stirred, and after 22 hours, hydrochloric acid and THF are added successively to dilute the reaction solution, and then the diluted reaction solution is centrifuged at 10000rpm for 10 minutes, the liquid after centrifugation is collected, and the solvent is removed by rotary evaporation. The obtained solid is redissolved with dichloromethane, the insoluble solid is removed by filtration, and the solid is placed at -20°C for one week for sedimentation. The solid obtained by sedimentation is then collected by filtration, washed with water, and dissolved and precipitated again with dichloromethane to obtain the target polymer. The degree of polymerization can be regulated by changing the iron source, reaction concentration and stirring rate.

[0030] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions. The sentence "includes an element defined by ... does not exclude the existence of other identical elements in the process, method, article or device including the element".

[0031] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. Synthesis of organic polymers containing thiophene structures by iron-catalyzed carbon-hydrogen activation method, characterized in that: Metallic iron is used as a catalyst, and the synthesis method is a carbon-hydrogen activation coupling method, and there is no need to cap the product, wherein the method comprises: S1: After the monomer and the ligand are mixed, hydrated ferric chloride (0.067 M) dissolved in THF is added, and then a toluene solution of trimethylaluminum (1.6 M) is slowly added dropwise, and finally an oxidant diethyl oxalate is added to obtain a mixed solution; S2: The mixed solution is heated and stirred. After 22 hours, hydrochloric acid and THF are added successively to dilute the reaction solution. The diluted reaction solution is then centrifuged at 10,000 rpm for 10 minutes. The liquid after centrifugation is collected, and the solvent is removed by rotary evaporation. The obtained solid is redissolved in dichloromethane, and the insoluble solid is removed by filtration. The solid is placed at -20°C for one week for sedimentation. The precipitated solid is then collected by filtration, washed with water, and dissolved and precipitated again in dichloromethane to obtain the target polymer.

2. The method for synthesizing an organic polymer containing a thiophene structure by an iron-catalyzed carbon-hydrogen activation method according to claim 1, characterized in that: The monomer is a compound with thiophene structures at both ends, and the THF solution of ferric chloride and the toluene solution of trimethylaluminum can also be a combined solution of iron salt+ligand+base+oxidant.

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