Epiindoledione polymer as well as preparation method and application thereof
By preparing epiindoledione polymers and using Stille coupling reaction to form polymers with amide and conjugated aromatic systems, the shortcomings of existing electrochromic materials in terms of stability and color range are solved, and electrochromic effects with high stability and fast response are achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HANGZHOU BAIHE CLARIANT PIGMENTS CO LTD
- Filing Date
- 2026-03-27
- Publication Date
- 2026-05-12
AI Technical Summary
Existing electrochromic polymer materials still have room for improvement in performance, especially in terms of stability and color range, and there is a lack of electrochromic materials with structural diversity.
A metaindole-2-ketone polymer was prepared by synthesizing a first and second monomer with specific structures via Stille coupling reaction in the presence of a palladium catalyst and an organic solvent, forming a polymer with an amide and conjugated aromatic system, suitable for electrochromic materials.
This polymer is orange in the neutral state and transparent in the oxidized state. It has good chemical stability, sensitivity, and short response time, and maintains good optical contrast. It is suitable for smart windows, automatic anti-glare rearview mirrors, and electronic display devices.
Smart Images
Figure CN122011343A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of electrochromic materials technology, and in particular to an epiindoledione polymer, its preparation method, and its application. Background Technology
[0002] Electrochromism refers to the phenomenon where a material's optical properties (such as reflectivity, transmittance, and absorptivity) undergo stable and reversible changes under the influence of an applied electric field, primarily manifested as a change in color. This process is typically due to redox reactions within the material, accompanied by ion insertion / extraction and electron migration. Electrochromic materials, due to their rich color variations and high stability, are widely used in fields such as smart windows, automatic anti-glare rearview mirrors, adaptive camouflage, and electronic display devices.
[0003] Currently, various electrochromic polymer systems have been extensively studied and applied. For example, polypyrrole, due to its excellent conductivity and electrochemical stability, is widely used in smart windows and displays; polyaniline, due to its polymorphic reversible color-changing behavior and simple synthesis process, has become one of the most mature electrochromic materials; in addition, polythiophenes (such as poly(3,4-ethylenedioxythiophene), PEDOT) have also shown great potential in flexible electronic devices due to their excellent electrochromic properties and high contrast.
[0004] However, despite the relatively mature performance of these materials, it is still of great significance to develop electrochromic polymers with novel structures, higher stability, or wider color gradation range. Summary of the Invention
[0005] The purpose of this invention is to provide an epiindoledione polymer, its preparation method and application, to expand the structural diversity of electrochromic materials and improve their performance.
[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a metaindole-dione polymer having the structure shown in Formula I: Formula I; In Equation I, the value of n ranges from 16 to 20.
[0007] This invention also provides a method for preparing epiindoledione polymers, comprising the following steps: Under a protective atmosphere, the first monomer, the second monomer, the palladium catalyst, and an organic solvent were mixed and subjected to a Stille coupling reaction to obtain an epiindoledione polymer. The first monomer has the structure shown in Formula II: Formula II; The second monomer has the structure shown in Formula III: Formula III.
[0008] Furthermore, in the preparation method, the palladium catalyst includes one or more of tetra(triphenylphosphine)palladium, tris(dibenzylacetone)palladium, palladium dichloride, and [1,1'-bis(diphenylphosphine)ferrocene]palladium dichloride.
[0009] Furthermore, in the preparation method, the molar ratio of the first monomer, the second monomer and the palladium catalyst is 1:1:0.05 to 1:1:0.1.
[0010] Furthermore, in the preparation method, the conditions for the Stille coupling reaction include: a reaction temperature of 90~130℃ and a reaction time of 48~72h.
[0011] Furthermore, in the preparation method, the preparation method of the first monomer includes the following steps: (1) p-Bromoaniline undergoes a substitution reaction with ethyl chloroacetate to give (4-bromophenyl)glycine ethyl ester; (2) Ethyl (4-bromophenyl)glycine reacts with diethyl oxalate in a condensation reaction to give diethyl 2-((4-bromophenyl)amino)malonate; (3) Diethyl 2-((4-bromophenyl)amino)malonate undergoes a nucleophilic addition-elimination reaction with p-bromoaniline to give diethyl 2,3-bis((4-bromophenyl)amino)fumarate; (4) Diethyl 2,3-bis((4-bromophenyl)amino)fumarate reacts with Dowson oil to give ethyl 6-bromo-3-((4-bromophenyl)amino)-4-oxo-1,4-dihydroquinoline-2-carboxylate. (5) 6-bromo-3-((4-bromophenyl)amino)-4-oxo-1,4-dihydroquinoline-2-carboxylate undergoes a cyclization condensation reaction with polyphosphoric acid to give 2,8-dibromo-5,11-dihydrodibenzo[b,g][1,5]naphthidine-6,12-dione; (6) 2,8-Dibromo-5,11-dihydrodibenzo[b,g][1,5]naphthidine-6,12-dione undergoes a substitution reaction with 1-bromo-2-propylheptane to give the first monomer.
[0012] Furthermore, in the preparation method, the preparation method of the first monomer includes: The molar ratio of p-bromoaniline to ethyl chloroacetate in step (1) is 1:1 to 1:1.2; the conditions for the substitution reaction in step (1) include: a reaction temperature of 70 to 100°C and a reaction time of 8 to 12 h. The molar ratio of (4-bromophenyl)glycine ethyl ester to diethyl oxalate in step (2) is 1:1 to 1:1.2; the conditions for the condensation reaction in step (2) include: the reaction temperature is room temperature and the reaction time is 24 to 72 hours. The molar ratio of 2-((4-bromophenyl)amino)malonate diethyl ester to p-bromoaniline in step (3) is 1:1 to 1:1.2; the conditions for the nucleophilic addition-elimination reaction in step (3) include: a reaction temperature of 60 to 100 °C and a reaction time of 2 to 8 h; The mass ratio of the 2,3-bis((4-bromophenyl)amino)fumarate diethyl ester to the volume of the Dowson oil in step (4) is 1 g: 3~15 mL; the reaction conditions in step (4) include: a reaction temperature of 240~280℃ and a reaction time of 0.5~1 h; In step (5), the mass ratio of ethyl 6-bromo-3-((4-bromophenyl)amino)-4-oxo-1,4-dihydroquinoline-2-carboxylate to the polyphosphoric acid is 1:15~20; the conditions for the cyclization condensation reaction in step (5) include: a reaction temperature of 140~160℃ and a reaction time of 2~4h; The molar ratio of 2,8-dibromo-5,11-dihydrodibenzo[b,g][1,5]naphthidine-6,12-dione to 1-bromo-2-propylheptane in step (6) is 1:10 to 1:15; the conditions for the substitution reaction in step (6) include: a reaction temperature of 120 to 140°C and a reaction time of 2 to 4 hours.
[0013] Furthermore, in the preparation method, the preparation method of the second monomer includes the following steps: 2-(2-ethylhexyl)cyclopentylthiophene, n-butyllithium, and tributyltin chloride undergo a substitution reaction to yield a second monomer.
[0014] Furthermore, in the preparation method, in the preparation method of the second monomer, the molar ratio of 2-(2-ethylhexyl)cyclopentylthiophene to n-butyllithium is 1:2~2.2, and the molar ratio of 2-(2-ethylhexyl)cyclopentylthiophene to tributyltin chloride is 1:2~2.2; the conditions for the substitution reaction include: the reaction temperature is room temperature, and the reaction time is 16~18h.
[0015] The present invention also provides an application of epiindoledione polymers in electrochromic materials.
[0016] As can be seen from the above technical solution, compared with the prior art, the present invention has the following beneficial effects: This invention provides an epiindole-dione polymer. Epiindole-dione, as a heterocyclic monomer with a unique structure and easy functionalization, contains both amide and conjugated aromatic systems in its molecular structure, exhibiting good electron transport capabilities and tunable electrochemical activity. The film prepared from this compound is orange in the neutral state and transparent in the oxidized state, with an optical contrast ratio of 37% in the 408 nm wavelength range, a coloring time of 0.96 s, and a fading time of 2.94 s. After 1250 cycles at step voltages of 0 V and 1.0 V, the optical contrast ratio still retains 25% of its original value, making it a chemically stable, highly sensitive, and short-response electrochromic material. Therefore, electrochromic polymers constructed using epiindole-dione as a monomer hold promise for expanding the structural diversity of electrochromic materials and improving their performance. Attached Figure Description
[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below.
[0018] Figure 1 Cyclic voltammetry of the electrochromic polymer film in Application Example 1; Figure 2 The UV-Vis spectra of the electrochromic polymer film in Application Example 1 at different voltages; Figure 3 The optical contrast and response time of the electrochromic polymer film at 408 nm are shown in the figure for Application Example 1. Figure 4 The spectral dynamic stability diagram of the electrochromic polymer film at 408 nm is shown in Example 1. Figure 5 Example 1 shows the color coordinates of the electrochromic polymer film at different voltages. Figure 6 The graph shows the brightness change of the electrochromic polymer film under different voltages in Application Example 1. Detailed Implementation
[0019] This invention provides a metaindole-dione polymer having the structure shown in Formula I: Formula I; In Equation I, the value of n ranges from 16 to 20.
[0020] This invention also provides a method for preparing epiindoledione polymers, comprising the following steps: Under a protective atmosphere, the first monomer, the second monomer, the palladium catalyst, and an organic solvent were mixed and subjected to a Stille coupling reaction to obtain an epiindoledione polymer. The first monomer has the structure shown in Formula II: Formula II; The second monomer has the structure shown in Formula III: Formula III.
[0021] In this invention, the palladium catalyst preferably comprises one or more of tetra(triphenylphosphine)palladium, tris(dibenzylacetone)palladium, palladium dichloride, and [1,1'-bis(diphenylphosphine)ferrocene]palladium dichloride, more preferably tetra(triphenylphosphine)palladium, tris(dibenzylacetone)palladium, palladium dichloride, or [1,1'-bis(diphenylphosphine)ferrocene]palladium dichloride, and more preferably tetra(triphenylphosphine)palladium.
[0022] In this invention, the molar ratio of the first monomer, the second monomer and the palladium catalyst is preferably 1:1:0.05 to 1:1:0.1, more preferably 1:1:0.08 to 1:1:0.1, and even more preferably 1:1:0.093.
[0023] In this invention, the organic solvent preferably includes one or more of N,N-dimethylformamide, toluene, xylene, and tetrahydrofuran, more preferably N,N-dimethylformamide, toluene, xylene, or tetrahydrofuran, and even more preferably N,N-dimethylformamide.
[0024] In this invention, the mass ratio of the first monomer to the volume of the organic solvent is preferably 0.3g:10~20mL, more preferably 0.3g:10~15mL, and even more preferably 0.3g:10mL.
[0025] In this invention, the conditions for the Stille coupling reaction include: a reaction temperature preferably of 90~130℃, more preferably of 90~100℃, and even more preferably of 90℃; and a reaction time preferably of 48~72h, more preferably of 48~56h, and even more preferably of 48h.
[0026] In this invention, the Stille coupling reaction is preferably followed by a post-treatment, specifically including the following steps: after the reaction is completed, the mixture is cooled to room temperature, the reaction solution is poured into methanol, and filtered to obtain a filter cake; the filter cake is sequentially passed through methanol, acetone, petroleum ether, and chloroform for extraction, finally obtaining a chloroform extraction solution, which is then evaporated to dryness to obtain the epiindole-dione polymer. This invention does not impose special limitations on the conditions in the above post-treatment; well-known methods in the art can be used.
[0027] In this invention, the preparation method of the first monomer is as follows, including the following steps: ; (1) p-Bromoaniline undergoes a substitution reaction with ethyl chloroacetate to give (4-bromophenyl)glycine ethyl ester; (2) Ethyl (4-bromophenyl)glycine reacts with diethyl oxalate in a condensation reaction to give diethyl 2-((4-bromophenyl)amino)malonate; (3) Diethyl 2-((4-bromophenyl)amino)malonate undergoes a nucleophilic addition-elimination reaction with p-bromoaniline to give diethyl 2,3-bis((4-bromophenyl)amino)fumarate; (4) Diethyl 2,3-bis((4-bromophenyl)amino)fumarate reacts with Dowson oil to give ethyl 6-bromo-3-((4-bromophenyl)amino)-4-oxo-1,4-dihydroquinoline-2-carboxylate. (5) 6-bromo-3-((4-bromophenyl)amino)-4-oxo-1,4-dihydroquinoline-2-carboxylate undergoes a cyclization condensation reaction with polyphosphoric acid to give 2,8-dibromo-5,11-dihydrodibenzo[b,g][1,5]naphthidine-6,12-dione; (6) 2,8-Dibromo-5,11-dihydrodibenzo[b,g][1,5]naphthidine-6,12-dione undergoes a substitution reaction with 1-bromo-2-propylheptane to give the first monomer.
[0028] In this invention, the method for preparing the first monomer includes: Step (1) specifically includes the following steps: under a protective atmosphere, bromoaniline, ethyl chloroacetate, anhydrous sodium acetate and anhydrous ethanol are mixed and subjected to a substitution reaction, and after post-treatment, (4-bromophenyl)glycine ethyl ester is obtained; The molar ratio of p-bromoaniline to ethyl chloroacetate in step (1) is preferably 1:1 to 1:1.2, more preferably 1:1 to 1:1.1, and even more preferably 1:1; In step (1), the molar ratio of p-bromoaniline to anhydrous sodium acetate is preferably 1:1 to 1:2, more preferably 1:1 to 1:1.5, and even more preferably 1:1; In step (1), the volume ratio of p-bromoaniline to anhydrous ethanol is not limited, as long as the reaction can proceed; specifically in the example, the volume ratio of p-bromoaniline to anhydrous ethanol is 1:1.49. The conditions for the substitution reaction in step (1) include: the reaction temperature is preferably 70~100℃, more preferably 75~85℃, and even more preferably 80℃; the reaction time is preferably 8~12h, more preferably 8~10h, and even more preferably 8h. The post-processing in step (1) specifically includes the following steps: stopping heating, cooling the reaction solution to room temperature, pouring it into water, stirring to produce a white solid, filtering, washing the filter cake with water, drying the filter cake at room temperature, and recrystallizing it with industrial ethanol; the present invention does not limit the conditions in the above post-processing, and any solution well known in the art can be used; Step (2) specifically includes the following steps: Under a protective atmosphere, sodium block, diethyl oxalate, ethyl (4-bromophenyl)glycine and anhydrous ethanol are mixed and subjected to a condensation reaction, and after post-treatment, diethyl 2-((4-bromophenyl)amino)malonate is obtained. The molar ratio of (4-bromophenyl)glycine ethyl ester to diethyl oxalate in step (2) is preferably 1:1 to 1:1.2, more preferably 1:1 to 1:1.1, and even more preferably 1:1; In step (2), the molar ratio of (4-bromophenyl)glycine ethyl ester to sodium block is preferably 1:1 to 1:2, more preferably 1:1 to 1:1.5, and even more preferably 1:1.1; In step (2), the mass ratio of (4-bromophenyl)glycine ethyl ester to the volume ratio of anhydrous ethanol is not limited, as long as the reaction can proceed; specifically in the example, the mass ratio of (4-bromophenyl)glycine ethyl ester to the volume ratio of anhydrous ethanol is 1g:3.87mL. The conditions for the condensation reaction in step (2) include: the reaction temperature is preferably room temperature; the reaction time is preferably 24~72h, more preferably 24~48h, and even more preferably 24h; The post-processing in step (2) specifically includes the following steps: stop stirring, distill off the solvent under reduced pressure, add water and acetic acid to the three-necked flask and stir, then extract with ethyl acetate, wash the organic layer with water until neutral, dry with anhydrous sodium sulfate and then distill under reduced pressure; the present invention does not limit the conditions in the above post-processing, and any solution known in the art can be used; Step (3) specifically includes the following steps: Under a protective atmosphere, diethyl 2-((4-bromophenyl)amino)malonate, p-bromoaniline, concentrated hydrochloric acid and anhydrous ethanol are mixed and subjected to a nucleophilic addition-elimination reaction, and after post-treatment, diethyl 2,3-bis((4-bromophenyl)amino)fumarate is obtained. The molar ratio of 2-((4-bromophenyl)amino)malonate diethyl ester to p-bromoaniline in step (3) is preferably 1:1 to 1:1.2, more preferably 1:1 to 1:1.1, and even more preferably 1:1; In step (3), the molar ratio of diethyl 2-((4-bromophenyl)amino)malonate to HCl in concentrated hydrochloric acid is preferably 10:1 to 80:1, more preferably 10:1 to 40:1, and even more preferably 10:1; In step (3), the mass ratio of diethyl 2-((4-bromophenyl)amino)malonate to the volume ratio of anhydrous ethanol is not limited, as long as the reaction can proceed; specifically in the example, the mass ratio of diethyl 2-((4-bromophenyl)amino)malonate to the volume ratio of anhydrous ethanol is 1g:2.65mL. The conditions for the nucleophilic addition-elimination reaction in step (3) include: the reaction temperature is preferably 60~100℃, more preferably 80~100℃, and even more preferably 80℃; the reaction time is preferably 2~8h, more preferably 4~6h, and even more preferably 4h. The post-processing in step (3) specifically includes the following steps: stop heating, cool to room temperature, pour the reaction solution into a beaker, place it in an ice bath until solid precipitates, filter, wash the filter cake quickly with ice ethanol, and dry it to obtain a light yellow solid. The cis and trans can be separated by using petroleum ether: ethyl acetate = 10:1. The present invention does not limit the conditions in the above post-processing, and any solution known in the art can be used. Step (4) specifically includes the following steps: Under a protective atmosphere, a portion of Dowfield oil is heated to reflux, and 2,3-bis((4-bromophenyl)amino)fumarate diethyl ester is mixed with the remaining Dowfield oil and preheated. The preheated mixture is added to the refluxed Dowfield oil for reaction, and after post-treatment, 6-bromo-3-((4-bromophenyl)amino)-4-oxo-1,4-dihydroquinoline-2-carboxylic acid ethyl ester is obtained. In step (4), the mass ratio of 2,3-bis((4-bromophenyl)amino)fumarate diethyl ester to the volume of Dowson oil is preferably 1 g: 3~15 mL, more preferably 1 g: 8~12 mL, and even more preferably 1 g: 10 mL. The reaction conditions in step (4) include: the reaction temperature is preferably 240~280℃, more preferably 250~270℃, and even more preferably 265℃; the reaction time is preferably 0.5~1h, more preferably 0.5~0.8h, and even more preferably 0.5h; The post-processing in step (4) specifically includes the following steps: while the reaction solution is hot, stir and cool it to room temperature to precipitate a large amount of solid, filter it, wash the filter cake with petroleum ether, and air dry it naturally; the present invention does not limit the conditions in the above post-processing, and any solution known in the art can be used; Step (5) specifically includes the following steps: heating polyphosphoric acid for a period of time, then adding ethyl 6-bromo-3-((4-bromophenyl)amino)-4-oxo-1,4-dihydroquinoline-2-carboxylate, and carrying out a cyclization condensation reaction under a protective atmosphere, and then obtaining 2,8-dibromo-5,11-dihydrodibenzo[b,g][1,5]naphthidine-6,12-dione after post-treatment; In step (5), the mass ratio of ethyl 6-bromo-3-((4-bromophenyl)amino)-4-oxo-1,4-dihydroquinoline-2-carboxylate to polyphosphoric acid is preferably 1:15~20, more preferably 1:15~17, and even more preferably 1:15; The conditions for the cyclization condensation reaction in step (5) include: the reaction temperature is preferably 140~160℃, more preferably 140~150℃, and even more preferably 140℃; the reaction time is preferably 2~4h, more preferably 2~3h, and even more preferably 2h. The post-processing in step (5) specifically includes the following steps: after cooling to room temperature, pour the reaction solution into an ice-water mixture, continue stirring and filter, and wash the filter cake with water until neutral; the present invention does not limit the conditions in the above post-processing, and any solution known in the art can be used; Step (6) specifically includes the following steps: Under a protective atmosphere, 2,8-dibromo-5,5a,11,11a-tetrahydrodibenzo[b,g][1,5]furan-6,12-dione, 1-bromo-2-propylheptane, potassium carbonate and N,N-dimethylformamide are mixed and subjected to a substitution reaction, and the first monomer is obtained after post-treatment; The molar ratio of 2,8-dibromo-5,11-dihydrodibenzo[b,g][1,5]naphthidine-6,12-dione to 1-bromo-2-propylheptane in step (6) is preferably 1:10 to 1:15, more preferably 1:10 to 1:12, and even more preferably 1:10. In step (6), the molar ratio of 2,8-dibromo-5,5a,11,11a-tetrahydrodibenzo[b,g][1,5]-furan-6,12-dione to potassium carbonate is preferably 1:2 to 1:20, more preferably 1:10 to 1:15, and even more preferably 1:10. In step (6), the mass ratio of 2,8-dibromo-5,5a,11,11a-tetrahydrodibenzo[b,g][1,5]furan-6,12-dione to the volume ratio of N,N-dimethylformamide is not limited, as long as the reaction can proceed; specifically in the examples, the mass ratio of 2,8-dibromo-5,5a,11,11a-tetrahydrodibenzo[b,g][1,5]furan-6,12-dione to the volume ratio of N,N-dimethylformamide is 1g:60mL; The conditions for the substitution reaction in step (6) include: the reaction temperature is preferably 120~140℃, more preferably 120~130℃, and even more preferably 120℃; the reaction time is preferably 2~4h, more preferably 2~3h, and even more preferably 2h. The post-processing in step (6) specifically includes the following steps: after cooling to room temperature, the reaction solution is poured into water, stirred and filtered to obtain a filter cake, extracted with saturated sodium chloride and dichloromethane, the organic phase is collected and dried with anhydrous sodium sulfate, and the monosubstituted product, i.e. the first monomer, is separated by column chromatography after drying; the present invention does not limit the conditions in the above post-processing, and a scheme well known in the art can be used.
[0029] In this invention, the method for preparing the second monomer includes the following steps: 2-(2-ethylhexyl)cyclopentylthiophene, n-butyllithium, and tributyltin chloride undergo a substitution reaction to yield a second monomer.
[0030] In this invention, the method for preparing the second monomer includes: The substitution reaction of 2-(2-ethylhexyl)cyclopentylthiophene, n-butyllithium, and tributyltin chloride specifically includes the following steps: Under a protective atmosphere, 2-(2-ethylhexyl)cyclopentylthiophene is dissolved in tetrahydrofuran, n-butyllithium is added dropwise at -78°C, and the mixture is stirred at 0°C. After stirring, tributyltin chloride is added dropwise, and the substitution reaction is carried out at room temperature. After post-treatment, a second monomer is obtained. The molar ratio of 2-(2-ethylhexyl)cyclopentylthiophene to n-butyllithium is preferably 1:2 to 2.2, more preferably 1:2.05 to 2.1, and even more preferably 1:2.08; The molar ratio of 2-(2-ethylhexyl)cyclopentylthiophene to tributyltin chloride is preferably 1:2 to 2.2, more preferably 1:2.05 to 2.1, and even more preferably 1:2.08; The mass ratio of 2-(2-ethylhexyl)cyclopentylthiophene to the volume ratio of tetrahydrofuran is not limited, as long as the reaction can proceed; in the specific examples, the mass ratio of 2-(2-ethylhexyl)cyclopentylthiophene to the volume ratio of tetrahydrofuran is 1g:24.9mL. The conditions for the substitution reaction include: the reaction temperature is preferably room temperature; the reaction time is preferably 16-18 h, more preferably 16-17 h, and even more preferably 16 h; The post-processing in the preparation method of the second monomer specifically includes the following steps: separation and purification by alumina chromatography column; the present invention does not limit the conditions in the above post-processing, and any scheme well known in the art can be used.
[0031] In this invention, unless otherwise specified, nitrogen can be selected as the protective atmosphere in the preparation method of epiindoledione polymer.
[0032] The present invention also provides an application of epiindoledione polymers in electrochromic materials.
[0033] In this invention, the method of the above application is not limited, and any method well known in the art can be used.
[0034] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0035] Example 1
[0036] This embodiment provides a method for preparing epiindoledione polymers, including the following steps: (1) Preparation of the first monomer EPD-Br: (1.1) Add p-bromoaniline (53.75 mL, 0.50 mol) and ethyl chloroacetate (52.6 mL, 0.50 mol), anhydrous sodium acetate (42 g, 0.50 mol), and anhydrous ethanol 80 mL to a 250 mL single-necked flask. Under magnetic stirring and nitrogen protection, the mixture is heated to 80 °C and refluxed for 0.5 h. As the reaction proceeds, the reaction solution gradually turns into a white suspension. The reaction is monitored by TLC. After 8 h, the starting material spot is still present. Stop heating and slowly cool the reaction solution to room temperature. Pour it into 500 mL of water and stir to produce a white solid. Filter the solution and wash the filter cake with 1000 mL of water. After drying the filter cake at room temperature, recrystallize it with 100 mL of industrial ethanol to obtain (4-bromophenyl)glycine ethyl ester. (1.2) Under nitrogen protection, 100 mL of redistilled anhydrous ethanol was added to a 250 mL three-necked flask, followed by sodium lumps (2.5 g, 0.11 mol). The reaction was allowed to proceed until the sodium lumps disappeared. Diethyl oxalate (13.5 mL, 0.10 mol) was added first, followed by (4-bromophenyl)glycine ethyl ester (25.87 g, 0.10 mol). The mixture was stirred at room temperature for 24 h until the solution turned orange-red. Stirring was stopped, and the solvent was distilled off under reduced pressure. 200 mL of water and 7.5 g of acetic acid were added to the three-necked flask and stirred for 1 h. The mixture was then extracted with ethyl acetate (50 mL × 3). The organic layer was washed with water until neutral, dried over anhydrous sodium sulfate, and then distilled under reduced pressure to obtain diethyl 2-((4-bromophenyl)amino)malonate. (1.3) Diethyl 2-((4-bromophenyl)amino)malonate (22.68 g, 0.09 mol) was added to 60 mL of anhydrous ethanol, 10.45 mL of p-bromoaniline (0.09 mol), and 0.75 mL of concentrated hydrochloric acid (0.009 mol HCl). The mixture was refluxed at 80 °C for 4 h under nitrogen protection. Heating was stopped, and the mixture was cooled to room temperature. The reaction solution was poured into a 100 mL beaker and placed in an ice bath for 12 h until a solid precipitated. The mixture was filtered, and the filter cake was quickly washed with 20 mL of ice-cold ethanol. After drying, a light yellow solid was obtained. The cis and trans forms could be separated by using petroleum ether:ethyl acetate = 10:1 to obtain diethyl 2,3-bis((4-bromophenyl)amino)fumarate. (1.4) Under nitrogen protection, 100 mL of Dowson oil was added to a 250 mL three-necked flask and heated to 265 °C under reflux; 15 g of 2,3-bis((4-bromophenyl)amino)fumarate was preheated to 150 °C in 50 mL of Dowson oil; the mixture was added dropwise to the three-necked flask over 0.5 h and kept warm for another 0.5 h; while still hot, the reaction solution was poured into a 500 mL beaker, stirred and cooled to room temperature, at which point a large amount of solid precipitated. The solid was filtered, the filter cake was washed with petroleum ether and air-dried to obtain ethyl 6-bromo-3-((4-bromophenyl)amino)-4-oxo-1,4-dihydroquinoline-2-carboxylate; (1.5) Add 150g of polyphosphoric acid to a 250mL three-necked flask, stir and heat to 140℃. At this time, the viscosity of the system decreases. Within 2h, add 10g of ground ethyl 6-bromo-3-((4-bromophenyl)amino)-4-oxo-1,4-dihydroquinoline-2-carboxylate and continue to keep warm for 2h. After cooling to room temperature, pour the reaction solution into an ice-water mixture, continue stirring for 2h and then filter. Wash the filter cake with water until neutral to obtain 2,8-dibromo-5,5a,11,11a-tetrahydrodibenzo[b,g][1,5]furan-6,12-dione. (1.6) Under nitrogen protection, 2,8-dibromo-5,5a,11,11a-tetrahydrodibenzo[b,g][1,5]-furan-6,12-dione (0.420 g, 1 mmol), potassium carbonate (1.39 g, 10 mmol), and DMF (25 mL) were added to a 100 mL three-necked flask. The suspension was heated to 120 °C with stirring. After 1 h, the system turned orange-red. 1-bromo-2-ethylheptane (1.35 mL, 10 mmol) was added with a syringe within 2 h and kept warm for 2 h. After cooling to room temperature, the reaction solution was poured into 200 mL of water, stirred, and filtered to obtain a filter cake. The filter cake was extracted with saturated sodium chloride and dichloromethane. The organic phase was collected and dried with anhydrous sodium sulfate. After drying, column chromatography (developing solvent: dichloromethane: petroleum ether = 1:5) was used to separate the monosubstituted product EPD-Br. (2) Preparation of the second monomer CPDT-Sn: Under nitrogen protection, 2-(2-ethylhexyl)cyclopentylthiophene (1.545 g, 2.422 mmol) was dissolved in anhydrous tetrahydrofuran (38.4 mL), placed in a Schlenk tube at -78 °C, and n-butyllithium (2.017 mL, 5.0425 mmol) was added dropwise. After stirring for 90 min, the mixture was placed in an ice-water bath at 0 °C and stirred for another 60 min. The system was orange. After stirring, the mixture was returned to the -78 °C environment, and tributyltin chloride (2.017 mL, 5.0425 mmol) was added dropwise. After stirring for 1 h, the mixture was reacted at room temperature for 16 h. After the reaction was completed, the reaction solution was purified by alumina chromatography to obtain CPDT-Sn. (3) Preparation of epiindole-dione polymer EPD-CPDT: Under nitrogen protection, EPD-Br (0.3g, 0.43mmol), CPDT-Sn (0.419g, 0.43mmol), and tetrakis(triphenylphosphine)palladium (0.05g, 0.04mmol) were added to a flask in sequence, followed by the addition of anhydrous N,N-dimethylformamide (10mL). The reaction was refluxed at 90℃ for 48h. After the reaction was completed, the mixture was cooled to room temperature, and the reaction solution was poured into 300mL of methanol. The filter cake was obtained by suction filtration. The polymer was extracted sequentially through methanol, acetone, petroleum ether, and chloroform to obtain a chloroform extraction solution. The solution was then evaporated to dryness to obtain EPD-CPDT with a degree of polymerization n of 16~20.
[0037] Application Example 1
[0038] 5 mg of the polymer EPD-CPDT prepared in Example 1 was ultrasonically mixed with 1 mL of chloroform at 50 kHz for 10 min. The mixture was then sprayed onto the conductive surface of a 9 × 40 mm ITO glass film to obtain an electrochromic polymer film.
[0039] Performance tests were conducted on the electrochromic polymer film obtained in Example 1: Using an electrochemical workstation coupled with a UV-Vis spectrophotometer, the cyclic voltammetry curves, UV-Vis absorption at different voltages, optical contrast and response time at a specific wavelength, film stability under a step voltage, and color coordinates and brightness changes at different voltages were measured in a 0.1M tetrabutylammonium perchlorate / acetonitrile solution. Data processing results are shown below. Figures 1 to 6 As shown.
[0040] from Figure 1 It can be seen that the polymer film has redox peaks located at 0.8V and 0.9V.
[0041] from Figure 2 It can be seen that the polymer film is orange in the neutral state at 0V, and becomes transparent in the oxidized state at 1.0V.
[0042] Figure 3 The polymer film was tested at 408 nm wavelength, with an optical contrast of 37% at 0 V and 1.0 V, a coloring time of 0.96 s, and a fading time of 2.94 s.
[0043] Figure 4 The polymer film was tested and found to retain 25% of its original optical contrast after 1250 cycles at 408 nm, demonstrating excellent electrochemical stability.
[0044] from Figure 5 As can be seen, the color of the polymer film changes from orange to transparent.
[0045] from Figure 6 It can be seen that the brightness first increases and then decreases with the change of voltage.
[0046] In summary, the thin film prepared using the polymer described in this invention exhibits redox peaks, appears orange in the neutral state at 0V, and becomes transparent in the oxidized state at 1.0V. At the 408nm wavelength, the response time at both 0V and 1.0V increases with decreasing chain length, while the coloring and fading times also increase. Furthermore, at the 408nm wavelength, the optical contrast loss gradually increases after 1250 cycles, but the electrochromic material of this invention still possesses excellent performance.
[0047] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
Claims
1. A metaindole-dione polymer, characterized in that, It has the structure shown in Equation I: Equation I; In Equation I, the value of n ranges from 16 to 20.
2. The method for preparing an epiindole-dione polymer according to claim 1, characterized in that, Includes the following steps: Under a protective atmosphere, the first monomer, the second monomer, the palladium catalyst, and an organic solvent were mixed and subjected to a Stille coupling reaction to obtain an epiindoledione polymer. The first monomer has the structure shown in Formula II: Formula II; The second monomer has the structure shown in Formula III: Formula III.
3. The preparation method according to claim 2, characterized in that, The palladium catalyst includes one or more of tetra(triphenylphosphine)palladium, tris(dibenzylideneacetone)palladium, palladium dichloride, and [1,1'-bis(diphenylphosphine)ferrocene]palladium dichloride.
4. The preparation method according to claim 2 or 3, characterized in that, The molar ratio of the first monomer, the second monomer and the palladium catalyst is 1:1:0.05 to 1:1:0.
1.
5. The preparation method according to claim 4, characterized in that, The conditions for the Stille coupling reaction include: a reaction temperature of 90~130℃ and a reaction time of 48~72h.
6. The preparation method according to claim 2, characterized in that, The preparation method of the first monomer includes the following steps: (1) p-Bromoaniline undergoes a substitution reaction with ethyl chloroacetate to give (4-bromophenyl)glycine ethyl ester; (2) Ethyl (4-bromophenyl)glycine reacts with diethyl oxalate in a condensation reaction to give diethyl 2-((4-bromophenyl)amino)malonate; (3) Diethyl 2-((4-bromophenyl)amino)malonate undergoes a nucleophilic addition-elimination reaction with p-bromoaniline to give diethyl 2,3-bis((4-bromophenyl)amino)fumarate; (4) Diethyl 2,3-bis((4-bromophenyl)amino)fumarate reacts with Dowson oil to give ethyl 6-bromo-3-((4-bromophenyl)amino)-4-oxo-1,4-dihydroquinoline-2-carboxylate. (5) 6-bromo-3-((4-bromophenyl)amino)-4-oxo-1,4-dihydroquinoline-2-carboxylate undergoes a cyclization condensation reaction with polyphosphoric acid to give 2,8-dibromo-5,11-dihydrodibenzo[b,g][1,5]naphthidine-6,12-dione; (6) 2,8-Dibromo-5,11-dihydrodibenzo[b,g][1,5]naphthidine-6,12-dione undergoes a substitution reaction with 1-bromo-2-propylheptane to give the first monomer.
7. The preparation method according to claim 6, characterized in that, In the preparation method of the first monomer: The molar ratio of p-bromoaniline to ethyl chloroacetate in step (1) is 1:1 to 1:1.2; the conditions for the substitution reaction in step (1) include: a reaction temperature of 70 to 100°C and a reaction time of 8 to 12 h. The molar ratio of (4-bromophenyl)glycine ethyl ester to diethyl oxalate in step (2) is 1:1 to 1:1.2; the conditions for the condensation reaction in step (2) include: the reaction temperature is room temperature and the reaction time is 24 to 72 hours. The molar ratio of 2-((4-bromophenyl)amino)malonate diethyl ester to p-bromoaniline in step (3) is 1:1 to 1:1.2; the conditions for the nucleophilic addition-elimination reaction in step (3) include: a reaction temperature of 60 to 100 °C and a reaction time of 2 to 8 h; The mass ratio of the 2,3-bis((4-bromophenyl)amino)fumarate diethyl ester to the volume of the Dowson oil in step (4) is 1 g: 3~15 mL; the reaction conditions in step (4) include: a reaction temperature of 240~280℃ and a reaction time of 0.5~1 h; In step (5), the mass ratio of ethyl 6-bromo-3-((4-bromophenyl)amino)-4-oxo-1,4-dihydroquinoline-2-carboxylate to the polyphosphoric acid is 1:15~20; the conditions for the cyclization condensation reaction in step (5) include: a reaction temperature of 140~160℃ and a reaction time of 2~4h; The molar ratio of 2,8-dibromo-5,11-dihydrodibenzo[b,g][1,5]naphthidine-6,12-dione to 1-bromo-2-propylheptane in step (6) is 1:10 to 1:15; the conditions for the substitution reaction in step (6) include: a reaction temperature of 120 to 140°C and a reaction time of 2 to 4 hours.
8. The preparation method according to claim 2, characterized in that, The preparation method of the second monomer includes the following steps: 2-(2-ethylhexyl)cyclopentylthiophene, n-butyllithium, and tributyltin chloride undergo a substitution reaction to yield a second monomer.
9. The preparation method according to claim 8, characterized in that, In the preparation method of the second monomer, the molar ratio of 2-(2-ethylhexyl)cyclopentylthiophene to n-butyllithium is 1:2~2.2, and the molar ratio of 2-(2-ethylhexyl)cyclopentylthiophene to tributyltin chloride is 1:2~2.2; the conditions for the substitution reaction include: the reaction temperature is room temperature, and the reaction time is 16~18h.
10. The application of the epiindole-dione polymer of claim 1 or the epiindole-dione polymer prepared by any one of claims 2 to 9 in electrochromic materials.