Electrochemical Polymerization Preparation and Application of a Triphenylamine Quinoxaline Conjugated Polymer

Abstract

An organic small molecule of 4,4′,4″,4″′-(quinoline-2,3,5,8-tetracarbonyl)tetra(N,N-diphenylaniline) with triphenylamine as the electron donor and quinoxaline as the electron acceptor, and a preparation method thereof, provides an electrochemical polymerization preparation method of a poly-4,4′,4″,4″′-(quinoline-2,3,5,8-tetracarbonyl)tetra(N,N-diphenylaniline) polymer film. This film can be used as an electrochromic material, showing a high optical contrast (~80%) and good cycle stability; provides an application of a poly-4,4′,4″,4″′-(quinoline-2,3,5,8-tetracarbonyl)tetra(N,N-diphenylaniline) polymer film as an electrochromic material. The present invention realizes the electrochemical polymerization preparation and realizes the application in the field of electrochromics.

Description

Technical Field

[0001] The present invention relates to a poly-4,4′,4″,4″′-(quinoline-2,3,5,8-tetracarbonyl)tetra(N,N-diphenylaniline) conjugate polymer and its monomer, a preparation method thereof, and its application in the field of electrochromism. Background Art

[0002] Electrochromic materials can undergo significant reversible color changes under the action of an applied voltage, and have received extensive attention due to their potential applications in many fields such as optical displays, smart windows, and anti-glare rearview mirrors. In the past few decades, a large amount of research efforts have been devoted to developing efficient electrochromic materials, which play a key role in electrochromic devices, aiming at low cost, high optical contrast, long-term stability, and customized color changes. So far, various electrochromic materials have been reported, involving metal oxides, viologens, conjugated conductive polymers, and metal complexes.

[0003] Organic electrochromic materials have the advantages of short switching time, convenient color adjustment, and high coloring efficiency. Polyarylamine derivatives have been proven to be an active electrochromic oxidation material due to their unique reversible redox behavior and can be colored through an electrooxidation process. To improve the performance of polyarylamine-based electrochromic materials, an effective strategy in molecular design is to introduce an electron-withdrawing part into the conjugated backbone. The current state-of-the-art linear configuration improves stability, switching speed, and coloring efficiency. However, the inherent strong intramolecular charge transfer transition of the donor-acceptor (D-A) type conjugate polymer results in broad and high absorption in the visible region, reducing their transmittance in the neutral state and limiting their application in smart color-changing windows. On the other hand, in the process of synthesizing D-A type conjugate compounds, the frequent use of noble metal catalysis for the coupling reaction between the donor and acceptor parts also increases their production cost. Although the conjugation can be cleaved to obtain a colorless electrochromic material, it will lead to limitations in color regulation and deterioration of device performance. Therefore, the development of colorless and color-tunable conjugated D-A type electrochromic materials remains a challenge. Summary of the Invention

[0004] To overcome the deficiencies of the prior art, the present invention provides a 4,4′,4″,4″′-(quinoline-2,3,5,8-tetracarbonyl)tetrakis(N,N-diphenylaniline) organic small molecule with triphenylamine as the electron donor and quinoxaline as the electron acceptor, and its preparation method, and provides an electrochemical polymerization preparation method for a 4,4′,4″,4″′-(quinoline-2,3,5,8-tetracarbonyl)tetrakis(N,N-diphenylaniline) polymer film. This film can be used as an electrochromic material, showing a high optical contrast (~80%) and good cycling stability in the visible light region, and provides the application of the poly-4,4′,4″,4″′-(quinoline-2,3,5,8-tetracarbonyl)tetrakis(N,N-diphenylaniline) polymer film as an electrochromic material.

[0005] To achieve the above-mentioned invention objectives, the present invention adopts the following technical solutions:

[0006] A 4,4′,4″,4″′-(quinoline-2,3,5,8-tetracarbonyl)tetrakis(N,N-diphenylaniline) monomer, whose structural formula is shown in formula (II):

[0007]

[0008] A preparation method for a 4,4′,4″,4″′-(quinoline-2,3,5,8-tetracarbonyl)tetrakis(N,N-diphenylaniline) monomer, and the monomer is prepared according to the following method:

[0009] I. Synthesis of 1,2-bis(4-diphenylamino)phenyl-1,2-dione

[0010] Under nitrogen protection at a temperature of 0 °C, 2.96 g (12 mmol) of triphenylamine is dissolved in anhydrous dichloromethane (40 mL), and after adding 1.60 g (12 mmol) of anhydrous aluminum chloride, the solution is stirred. The temperature of the reaction system is maintained below 0 °C, and 0.64 g (5 mmol) of oxalyl chloride is added dropwise. Stir at room temperature for 12 hours, separate the organic layer with a separatory funnel, and then extract and purify the obtained organic layer with water and dichloromethane in sequence to obtain an organic phase. Anhydrous magnesium sulfate is added to the organic phase for drying, and the solvent is removed from the dried organic phase by vacuum distillation to obtain a white powdery product.

[0011] II. Synthesis of 4,4′-(benzo[c][1,2,5]thiadiazole-4,7-dicarbonyl)bis(N,N-diphenylaniline)

[0012] Dissolve 1 g (3.4 mmol) of 4,7-dibromobenzo[c][1,2,5]thiadiazole in 30 mL of 1,4-dioxane, add 2.36 g (8.16 mmol) of triphenylamine boronic acid, 3 mL of aqueous potassium carbonate solution (2 mol / L), and 112 mg (0.1 mmol) of tetrakis(triphenylphosphine)palladium. Stir evenly under nitrogen protection at room temperature, then heat to reflux and react overnight. After the reaction is completed, cool to room temperature. After evaporating the solvent, add water to the residue, extract with dichloromethane, wash with saturated brine, collect the organic phase, dry with anhydrous sodium sulfate, remove the organic solvent under reduced pressure, separate and purify the obtained solid, and dry in vacuum to obtain an orange solid.

[0013]

[0014] III. Synthesis of 4,4′-bis(diphenylamine)-[1,1′:4′,1′-terphenyl]-2′,3′-diammonium chloride

[0015] Dissolve 1 g (1.6 mmol) of 4,4′-(benzo[c][1,2,5]thiadiazole-4,7-dicarbonyl)bis(N,N-diphenylaniline) obtained in Step II in ethanol (20 mL), add 0.5 g (7.1 mmol) of zinc powder, and then slowly dropwise add 5 mL of concentrated hydrochloric acid. Stir evenly under nitrogen protection at room temperature, then heat to reflux and react overnight. After the reaction is completed, cool to room temperature. Filter, concentrate the filtrate under reduced pressure, add water, extract with dichloromethane, wash with saturated brine, collect the organic phase, dry with anhydrous sodium sulfate, remove the organic solvent under reduced pressure, add a dichloromethane solution of hydrogen chloride and stir to form a salt, and dry in vacuum to obtain a white solid.

[0016]

[0017] IV. Synthesis of 4,4′,4″,4″′-(quinoline-2,3,5,8-tetracarbonyl)tetrakis(N,N-diphenylaniline)

[0018] Dissolve 515 mg (0.77 mmol) of 4,4′-bis(diphenylamine)-[1,1′:4′,1′-terphenyl]-2′,3′-diammonium chloride prepared in Step III and 462 mg (0.85 mmol) of 1,2-bis(4-diphenylamine)phenyl-1,2-dione prepared in Step I in 20 mL of acetic acid, and reflux for 6 hours under nitrogen protection. After the reaction is completed, cool to room temperature. Evaporate the solvent, add water to the residue, extract with dichloromethane, wash with saturated brine, collect the organic phase, dry with anhydrous sodium sulfate, remove the organic solvent under reduced pressure, separate and purify the obtained solid by column chromatography, and dry in vacuum to obtain a yellow solid.

[0019]

[0020] 4,4′,4″,4″′-(quinoline-2,3,5,8-tetracarbonyl)tetrakis(N,N-diphenylaniline) can be used as a monomer for electrochemically polymerizing to prepare a polymer film, and the polymer film has a structure as shown in (I):

[0021]

[0022] Furthermore, the preparation method of the polymer film is as follows: 4,4′,4″,4″′-(quinoline-2,3,5,8-tetracarbonyl)tetrakis(N,N-diphenylaniline) shown in formula (II) is used as a monomer and dissolved in a mixed solvent of toluene and acetonitrile. Indium tin oxide (ITO) transparent conductive glass is used as the working electrode, a platinum wire is used as the counter electrode, a silver wire is used as the reference electrode, and tetrabutylammonium hexafluorophosphate is used as the electrolyte. Cyclic voltammetry polymerization is carried out at 0 - 1.8 V, the scanning rate of cyclic voltammetry is 0.1 V / s, the number of cycles is 5 - 8, and a polymer film is obtained under electrochemical polymerization.

[0023] Furthermore, the concentration of the tetrabutylammonium hexafluorophosphate electrolyte in the present invention is 0.05 - 0.2 mol / L, preferably 0.1 mol / L.

[0024] Furthermore, the initial concentration of the 4,4′,4″,4″′-(quinoline-2,3,5,8-tetracarbonyl)tetrakis(N,N-diphenylaniline) monomer in the present invention is 0.1 - 0.5 mol / L, preferably 0.3 mol / L.

[0025] Application of a polymer film obtained by electrochemically polymerizing 4,4′,4″,4″′-(quinoline-2,3,5,8-tetracarbonyl)tetrakis(N,N-diphenylaniline) as a monomer in electrochromism.

[0026] Compared with the prior art, the advantages of the present invention are as follows:

[0027] 1. A triphenylamine-quinoxaline derivative structure 4,4′,4″,4″′-(quinoline-2,3,5,8-tetracarbonyl)tetrakis(N,N-diphenylaniline) containing multiple triphenylamine units is designed and synthesized, and a new polymer film is obtained by electrochemical polymerization.

[0028] 2. In the electrochromic electrochemical test, the polymer film realizes multi-level reversible color change at different voltages, and simultaneously has a high optical contrast and good stability of more than 500 cycles.

[0029] 3. It provides a new design idea for the design of electrochromic triphenylamine derivative structures. Description of the Drawings

[0030] Figure 1 1H NMR spectrum of 4,4′,4″,4″′-(quinoline-2,3,5,8-tetracarbonyl)tetrakis(N,N-diphenylaniline) prepared in Example 1 of the present invention.

[0031] Figure 2 13C NMR spectrum of 4,4′,4″,4″′-(quinoline-2,3,5,8-tetracarbonyl)tetrakis(N,N-diphenylaniline) prepared in Example 1 of the present invention.

[0032] Figure 3 Cyclic voltammogram of the monomer of 4,4′,4″,4″′-(quinoline-2,3,5,8-tetracarbonyl)tetrakis(N,N-diphenylaniline) prepared in Example 1 of the present invention.

[0033] Figure 4 Sweep rate-current cyclic voltammogram of the polymer film of 4,4′,4″,4″′-(quinoline-2,3,5,8-tetracarbonyl)tetrakis(N,N-diphenylaniline) prepared in Example 2 of the present invention.

[0034] Figure 5 UV-Vis absorption spectrum of the polymer film of 4,4′,4″,4″′-(quinoline-2,3,5,8-tetracarbonyl)tetrakis(N,N-diphenylaniline) prepared in Example 2 of the present invention.

[0035] Figure 6 Response time, contrast and cycling stability diagram of the polymer film of 4,4′,4″,4″′-(quinoline-2,3,5,8-tetracarbonyl)tetrakis(N,N-diphenylaniline) prepared in Example 2 of the present invention. Detailed implementation manners

[0036] The present invention will be further described below with reference to the accompanying drawings.

[0037] Refer to Figures 1 to 2 , a monomer of 4,4′,4″,4″′-(quinoline-2,3,5,8-tetracarbonyl)tetrakis(N,N-diphenylaniline) has the structural formula shown in Formula (II):

[0038]

[0039] I. Synthesis of 1,2-bis(4-diphenylamino)phenyl-1,2-diketone

[0040] Under nitrogen protection at a temperature of 0 °C, 2.96 g (12 mmol) of triphenylamine was dissolved in anhydrous dichloromethane (40 mL). After adding 1.60 g (12 mmol) of anhydrous aluminum chloride, the solution was stirred. While keeping the temperature of the reaction system below 0 °C, 0.64 g (5 mmol) of oxalyl chloride was added dropwise. The mixture was stirred at room temperature for 12 hours. The organic layer was separated with a separatory funnel, and then the obtained organic layer was extracted and purified successively with water and dichloromethane to obtain an organic phase. Anhydrous magnesium sulfate was added to the organic phase for drying. The dried organic phase was concentrated under reduced pressure to remove the solvent, and a white powdery product was obtained.

[0041] II. Synthesis of 4,4′-(benzo[c][1,2,5]thiadiazole-4,7-diyl)bis(N,N-diphenylaniline)

[0042] 1 g (3.4 mmol) of 4,7-dibromobenzo[c][1,2,5]thiadiazole was dissolved in 1,4-dioxane. 2.36 g (8.16 mmol) of triphenylamine boronic acid, 3 mL of aqueous potassium carbonate solution (2 mol / L), and 112 mg (0.1 mmol) of tetrakis(triphenylphosphine)palladium were added. The mixture was stirred evenly under nitrogen protection at room temperature and then heated, and the reaction was carried out overnight. After the reaction was completed, it was cooled to room temperature. After evaporating the solvent, water was added to the residue, and extraction was carried out with dichloromethane. Then it was washed with saturated brine, and the organic phase was collected. After drying with anhydrous sodium sulfate, the organic solvent was removed under reduced pressure. The obtained solid was separated and purified and dried in vacuo to obtain an orange solid.

[0043]

[0044] III. Synthesis of 4,4′-bis(diphenylamino)-[1,1′:4′,1′-terphenyl]-2′,3′-diammonium chloride

[0045] 1 g (1.6 mmol) of 4,4′-(benzo[c][1,2,5]thiadiazole-4,7-diyl)bis(N,N-diphenylaniline) obtained in step II was dissolved in ethanol (20 mL). Then 0.5 g (7.1 mmol) of zinc powder was added, and 5 mL of concentrated hydrochloric acid was slowly added dropwise. The mixture was stirred evenly under nitrogen protection at room temperature and then heated, and the reaction was carried out overnight. After the reaction was completed, it was cooled to room temperature. It was filtered, the filtrate was concentrated under reduced pressure, water was added, extraction was carried out with dichloromethane, and then it was washed with saturated brine. The organic phase was collected. After drying with anhydrous sodium sulfate, the organic solvent was removed under reduced pressure. A solution of hydrogen chloride in dichloromethane was added and stirred to form a salt, and then it was dried in vacuo to obtain a white solid.

[0046]

[0047] IV. Synthesis of 4,4″,4″′,4″″-(quinoline-2,3,5,8-tetrayl)tetrakis(N,N-diphenylaniline)

[0048] Dissolve 515 mg (0.77 mmol) of 4,4′-bis(diphenylamine)-[1,1′:4′,1′-triphenyl]-2′,3′-diammonium chloride prepared in Step 3 and 462 mg (0.85 mmol) of 1,2-bis(4-diphenylamine)phenyl-1,2-dione prepared in Step 1 in 20 mL of acetic acid, and reflux for 6 hours under nitrogen protection. After the reaction is completed, cool to room temperature. Rotate to dry the solvent, add water to the residue, extract with dichloromethane, wash with saturated brine, collect the organic phase, add anhydrous sodium sulfate for drying, remove the organic solvent under reduced pressure, separate and purify the obtained solid by column chromatography, and dry in vacuum to obtain a yellow solid.

[0049]

[0050] A 4,4′,4″,4″′-(quinoline-2,3,5,8-tetracarbonyl)tetrakis(N,N-diphenylaniline) can be used as a monomer for electrochemically polymerizing to prepare a polymer film, and the polymer film has a structure as shown in (I):

[0051]

[0052] Furthermore, the method for preparing the polymer film is as follows: Use 4,4′,4″,4″′-(quinoline-2,3,5,8-tetracarbonyl)tetrakis(N,N-diphenylaniline) shown in formula (II) as a monomer, dissolve it in a mixed solvent of toluene and acetonitrile, use indium tin oxide (ITO) transparent conductive glass as the working electrode, a platinum wire as the counter electrode, a silver wire as the reference electrode, and tetrabutylammonium hexafluorophosphate as the electrolyte. Perform cyclic voltammetry polymerization at 0 - 1.8 V, the scan rate of cyclic voltammetry is 0.1 V / s, and the number of cycles is 5 - 8, to obtain a polymer film under electrochemical polymerization.

[0053] Furthermore, the concentration of the tetrabutylammonium hexafluorophosphate electrolyte in the present invention is 0.05 - 0.2 mol / L, preferably 0.1 mol / L.

[0054] Furthermore, the initial concentration of the 4,4′,4″,4″′-(quinoline-2,3,5,8-tetracarbonyl)tetrakis(N,N-diphenylaniline) monomer in the present invention is 0.1 - 0.5 mol / L, preferably 0.3 mol / L.

[0055] Application of a polymer film obtained by electrochemically polymerizing 4,4′,4″,4″′-(quinoline-2,3,5,8-tetracarbonyl)tetrakis(N,N-diphenylaniline) as a monomer in electrochromism.

[0056] Example 1: Synthesis of 4,4′,4″,4″′-(quinoline-2,3,5,8-tetracarbonyl)tetrakis(N,N-diphenylaniline)

[0057] 515 mg (0.77 mmol) of 4,4′-bis(diphenylamine)-[1,1′:4′,1′-terphenyl]-2′,3′-diammonium chloride and 462 mg (0.85 mmol) of 1,2-bis(4-diphenylamine)phenyl-1,2-dione were added to a pre-washed and dried 100 ml two-necked flask. After protecting with nitrogen, 30 ml of acetic acid was added and refluxed for 6 hours, then the temperature was raised to 95 °C and reacted for 12 hours. After the reaction was completed, it was cooled to room temperature. The solvent was rotary evaporated, and the residue was extracted three times with water / dichloromethane (1:1), then washed with saturated brine, the organic phase was collected, dried over anhydrous sodium sulfate, concentrated under reduced pressure, and purified by column chromatography. Using 100-200 mesh silica gel as the stationary phase and a mixture of dichloromethane / petroleum ether with a volume ratio of 3:1 as the mobile phase for elution, the eluate containing the target compound was collected, the organic solvent was removed by distillation under reduced pressure, and vacuum dried to obtain 862 mg of yellow solid, with a yield of 82%. 1H NMR (600 MHz, CDCl 3 ) δ: 7.86 (s, 2H), 7.79 (d, J = 8.6 Hz, 4H), 7.61 (d, J = 8.7 Hz, 4H), 7.29 (m, 18H), 7.23 (dd, J 1 = 7.9 Hz, J 2 = 4.8 Hz, 12H), 7.17 (d, J = 8.2 Hz, 8H), 7.11 (t, J = 6.8 Hz, 4H), 7.05 (t, J = 6.6 Hz, 4H), 7.01 (t, J = 7.4 Hz, 4H). 13 C NMR (150 MHz, CDCl 3 ) δ: 150.31, 148.59, 147.77, 147.31, 138.21, 138.06, 132.37, 132.30, 131.73, 130.95, 129.39, 129.25, 128.85, 125.20, 124.66, 123.52, 122.94, 122.83, 121.68.

[0058] Example 2: Electro-polymerization of 4,4′,4″,4″′-(quinoline-2,3,5,8-tetracarbonyl)tetrakis(N,N-diphenylaniline) polymer film

[0059] 4,4′,4″,4″′-(quinoline-2,3,5,8-tetracarbonyl)tetrakis(N,N-diphenylaniline) was used as a monomer and dissolved in a mixed solvent of toluene and acetonitrile. ITO transparent conductive glass was used as the working electrode, a platinum wire as the counter electrode, and a silver wire as the reference electrode. Tetrabutylammonium hexafluorophosphate was used as the electrolyte. Cyclic voltammetry polymerization was carried out at -0.4 to 1.4 V. The scan rate of cyclic voltammetry was 0.1 V / s, and the number of cycles was 5 to 8. A polymer film was obtained under electrochemical polymerization. As attached Figure 3 The increasing current density represents the continuous deposition of the polymer on the electrode surface.

[0060] Example 3: Electrochemical performance test of 4,4′,4″,4″′-(quinoline-2,3,5,8-tetracarbonyl)tetrakis(N,N-diphenylaniline) polymer film

[0061] Tetrabutylammonium hexafluorophosphate (774 mg, 0.1 mol / L) was dissolved in pure propylene carbonate (20 mL) and ultrasonically dispersed evenly for use as a blank solution. All electrochemical tests were carried out in this blank solution.

[0062] Attached Figure 4 is the CV curves of the 4,4′,4″,4″′-(quinoline-2,3,5,8-tetracarbonyl)tetrakis(N,N-diphenylaniline) polymer film at different scan rates. Attached Figure 5 is the UV-visible absorption spectra of the 4,4′,4″,4″′-(quinoline-2,3,5,8-tetracarbonyl)tetrakis(N,N-diphenylaniline) polymer film at different voltages. The voltage range of the cyclic voltammetry test was 0 to 0.9 V. The test results showed that the 4,4′,4″,4″′-(quinoline-2,3,5,8-tetracarbonyl)tetrakis(N,N-diphenylaniline) polymer film prepared by the present invention had good redox reversibility; in the voltage range of 0 to 0.9 V, it was found by UV-visible absorption spectroscopy that the 4,4′,4″,4″′-(quinoline-2,3,5,8-tetracarbonyl)tetrakis(N,N-diphenylaniline) polymer film could achieve multi-level reversible color changes of yellow - red - coffee - gray - blue.

[0063] Attached Figure 6Test chart of the response time, contrast and cycling stability of the 4,4′,4″,4″′-(quinoline-2,3,5,8-tetracarbonyl)tetrakis(N,N-diphenylaniline) polymer film. Through the combined technology of ultraviolet spectrometer and electrochemical workstation, using the multi-potential step method of the electrochemical workstation: the initial potential is 0 V, the high potential is 0.9 V, the pulse time width is 10 s, and the scanning time is 10,000 s; the ultraviolet spectrum is set for spectral kinetics test, and the single-wavelength test is set at 775 nm. From the test results, we found that the optical contrast of the 4,4′,4″,4″′-(quinoline-2,3,5,8-tetracarbonyl)tetrakis(N,N-diphenylaniline) polymer film at 775 nm is, the coloring time and the fading time are 3.9 s and 2.5 s respectively, and the contrast still remains 91.2% after 500 cycles, showing good stability, providing some new ideas for the molecular design and performance research of triphenylamine derivatives in the field of electrochromics, and having potential applications in smart windows, display materials, and military camouflage.

Claims

1. Application of a polymer film with 4,4',4”,4”'-(quinoline-2,3,5,8-tetracarbonyl)tetrakis(N,N-diphenylaniline) as a monomer, characterized in that, the polymer film has a structure as shown in (Ⅰ): the polymer film is used for electrochromism to achieve multi-level reversible color changes of yellow - red - coffee - gray - blue.

2. The application according to claim 1, characterized in that, the polymer film is prepared by an electrochemical polymerization method: 4,4',4”,4”'-(quinoline-2,3,5,8-tetracarbonyl)tetrakis(N,N-diphenylaniline) is used as a monomer and dissolved in a mixed solvent of toluene and acetonitrile. With tetrabutylammonium hexafluorophosphate as the electrolyte, cyclic voltammetry polymerization is carried out at 0 - 1.8V, the polymerization sweep rate is 0.1V / s, and the number of cycles is 5 - 8. The polymer film is obtained by electrochemical polymerization.

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