A boron-dipyrromethene (bodipy)-based viologen-based bifunctional electrochromic material

Abstract

The application discloses a fluorobodipy as a core of a violet cyanine class bifunctional electrochromic material, and belongs to the field of intelligent color change. The fluorobodipy as a core of the violet cyanine class bifunctional electrochromic material has simple synthesis route, mild conditions and low cost. The device prepared by using the violet cyanine derivative with the fluorobodipy as a core designed by the application exhibits the electrochromic and electrofluorochromic double functions under the applied voltage, and has high optical contrast, fast response speed and good cycle stability, and has potential application value.

Description

Technical Field

[0001] This invention belongs to the field of intelligent color-changing, specifically relating to a bifunctional electrochromic material of iridescent based on fluorine-boron dipyrrole core, and its application in bifunctional electrochromic and electrofluorescent devices. Background Technology

[0002] Smart color change refers to a phenomenon where the optical properties of a material change under external stimuli, and it has wide applications in high-tech fields. For example, electrochromic materials can undergo reversible color changes with variations in applied voltage, and are widely used in smart color-changing windows, anti-glare glasses, and information displays. Electrofluorescent materials can exhibit significant and reversible changes in their fluorescence properties under the influence of applied voltage, and have potential applications in information display, bioimaging, and information storage, attracting considerable attention.

[0003] Violet is a collective term for N,N'-disubstituted 4,4'-bipyridine salts. Violet molecules possess excellent redox properties; under voltage-driven conditions, they can be reduced to monocationic radicals, exhibiting a significant color change, and are considered a promising electrochromic material with broad application prospects. Furthermore, fluoroboron dipyrrole and its derivatives exhibit excellent fluorescence properties. Therefore, introducing fluoroboron dipyrrole structural units into violet molecules to construct conjugated violet derivatives can further modulate the redox properties and optical properties of the material. Summary of the Invention

[0004] This invention utilizes molecular design to construct a novel bifunctional electrochromic material based on fluoroboron dipyrrole as its core. The synthetic route for this bifunctional electrochromic material is simple, the conditions are mild, and the cost is low. Devices prepared using this invention's violet derivative with a fluoroboron dipyrrole core exhibit both electrochromic and electrofluorescent functions under applied voltage, and possess high optical contrast, fast response speed, and good cycling stability, demonstrating potential application value.

[0005] This invention provides a bifunctional electrochromic material based on fluorinated boron dipyrrole core, with the chemical structural formula (I):

[0006]

[0007] The method for synthesizing the violet bifunctional electrochromic material BDP-V with fluoroboron dipyrrole as the core is as follows: 2,4-dimethoxypyrrole is reacted with benzaldehyde, 2,3-dichloro-5,6-dicyanobenzoquinone, and boron trifluoride diethyl ether to obtain phenylfluoroboron dipyrrole; then it is reacted with N-iodosuccinimide to generate diiodophenylfluoroboron dipyrrole; then it undergoes a coupling reaction with pyridineboronic acid to generate dipyridylphenylfluoroboron dipyrrole; finally, it is reacted with iodomethane to generate the target bifunctional electrochromic material BDP-V.

[0008] (1) Dissolve 2,4-dimethylpyrrole and benzaldehyde in anhydrous dichloromethane. Under a nitrogen atmosphere, add trifluoroacetic acid and stir at room temperature in the dark. React overnight. Then add 2,3-dichloro-5,6-dicyano-p-benzoquinone. Three hours later, add triethylamine and boron trifluoride ether. After the reaction is complete, evaporate the solvent. Add water to the residue and extract with dichloromethane. Wash with saturated brine and collect the organic phase. Add anhydrous magnesium sulfate and dry. Remove the organic solvent under reduced pressure. Separate and purify the obtained solid and dry under vacuum to obtain phenylfluoroboron dipyrrole.

[0009] (2) Dissolve phenyl fluoroboron dipyrrole in anhydrous dichloromethane, add N-iodosuccinimide in batches, stir overnight at room temperature, concentrate under reduced pressure after the reaction is complete, add water to the residue, extract with dichloromethane, wash with saturated brine, collect the organic phase, add anhydrous magnesium sulfate to dry, evaporate the solvent, separate and purify the obtained solid, and dry under vacuum to obtain diiodophenyl fluoroboron dipyrrole.

[0010] (3) Dissolve diiodophenylfluoroboron dipyrrole in 1,4-dioxane, add pyridine-4-boronic acid, cesium carbonate aqueous solution and tetra(triphenylphosphine)palladium in sequence, slowly heat to 100°C under nitrogen atmosphere, keep the temperature overnight, concentrate under reduced pressure after the reaction, extract with dichloromethane, wash with saturated brine, collect the organic phase, add anhydrous magnesium sulfate to dry, evaporate the solvent, separate and purify, and vacuum dry to obtain dipyridylphenylfluoroboron dipyrrole;

[0011] (4) Dissolve bispyridylphenylfluoroboron dipyrrole in acetonitrile solution, add iodomethane dropwise, slowly heat to 80°C, keep the reaction under nitrogen atmosphere overnight, remove solvent under reduced pressure, separate and purify, and vacuum dry to obtain a bifunctional material BDP-V of violet-based electrochromic and electrofluorescent properties with phenylfluoroboron dipyrrole as the core.

[0012] The synthesis process is as follows:

[0013]

[0014] In step (1), the molar ratio of 2,4-dimethoxypyrrole, benzaldehyde, 2,3-dichloro-5,6-dicyanobenzoquinone, triethylamine and boron trifluoride diethyl ether is 2.5:1:1:15:15. The reaction is carried out at room temperature for 12 to 24 hours.

[0015] In step (2), the molar ratio of phenyl fluoroboron dipyrrole and N-iodosuccinimide is 1:6, and the reaction is carried out at room temperature for 3 to 6 hours.

[0016] In step (3), the molar ratio of diiodophenyl fluoroboron dipyrrole, pyridine-4-boronic acid, cesium carbonate and tetra(triphenylphosphine)palladium is 1:6:18:0.1, the reaction temperature is 100℃, and the reaction time is 24-48h.

[0017] In step (4), the molar ratio of bispyridylphenylfluoroboron dipyrrole to iodomethane is 1:6, the reaction temperature is 80℃, and the reaction time is 12-24h.

[0018] The violet-based bifunctional electrochromic material BDP-V, with fluoroboron dipyrrole as its core, prepared according to this invention, is applied to the fabrication of a device. The device comprises a transparent conductive electrode, a bifunctional electrochromic and electrofluorescent material, ferrocene, and tetrabutylammonium tetrafluoroborate. The specific fabrication steps are as follows:

[0019] (1) Cut the transparent ITO conductive glass substrate into a fixed size and perform etching, ultrasonic cleaning, and ultraviolet ozone treatment; place a piece of sarin film with a hollow center and a small hole on one side between two pieces of ITO conductive glass, and heat-shape it under a hot press to prepare the device.

[0020] (2) A solution was prepared by dissolving BDP-V, a bifunctional electrochromic material of fluorine-boron dipyrrole as the core, ferrocene and tetrabutyltetrafluoroborate in N-methylpyrrolidone, and injected into the device under reduced pressure. The reserved small hole was then sealed with UV-cured adhesive.

[0021] In the preparation step (2), the concentrations of BDP-V, ferrocene, and tetrabutylammonium tetrafluoroborate are 0.05 mol / L, 0.05 mol / L, and 0.1 mol / L, respectively.

[0022] This invention has the following advantages:

[0023] The bifunctional electrochromic material designed in this invention features a simple, mild, and low-cost synthesis route. Devices prepared using a violetin derivative with a fluoroboron dipyrrole core, designed according to this invention, exhibit dual electrochromic and electrofluorescent functions under applied voltage, and possess high optical contrast, fast response speed, and good cycling stability, demonstrating potential application value. Attached Figure Description

[0024] Figure 1 The molecular structure of BDP-V, a bifunctional electrochromic material of violetin with a fluoroboron dipyrrole core synthesized in Example 1, is shown.

[0025] Figure 2 The images show the UV-Vis absorption spectra of the device based on the violet bifunctional electrochromic material BDP-V with fluorinated boron dipyrrole as the core, synthesized in Example 2, at different voltages.

[0026] Figure 3 The cyclic voltammetry curves are for devices based on the violet bifunctional electrochromic material BDP-V with fluorinated boron dipyrrole as the core synthesized in Example 2.

[0027] Figure 4 The images show the fluorescence emission spectra of the device based on the violet bifunctional electrochromic material BDP-V with fluorinated boron dipyrrole as the core, synthesized in Example 2, at different voltages. Detailed Implementation

[0028] Example 1:

[0029] Synthesis of bifunctional electrochromic material BDP-V and its application in electrochromic and electrofluorescent devices:

[0030]

[0031] (1) Preparation of intermediate phenylfluoroboron dipyrrole

[0032] 2,4-Dimethylpyrrole (1.189 g, 12.5 mmol) and benzaldehyde (0.53 g, 5 mmol) were added to 200 mL of anhydrous dichloromethane solution and stirred continuously. Under nitrogen protection, trifluoroacetic acid (50 μl, 0.00067 mmol) was added, and the mixture was stirred at room temperature in the dark for 24 h. Then, 2,3-dichloro-5,6-dicyanobenzoquinone (1.135 g, 5 mmol) and triethylamine (10 mL, 72 mmol) were added, and the reaction was carried out for 3 h. Then, boron trifluoride diethyl ether (10 mL, 74 mmol) was added, and the reaction was carried out at room temperature for 24 h. After the reaction was observed by TLC, the mixed solvent was evaporated, water was added to the residue, and the mixture was extracted with dichloromethane. The residue was then washed with saturated brine, and the organic phase was collected. After drying with anhydrous magnesium sulfate, the organic solvent was removed under reduced pressure. The obtained solid was separated, purified, and dried under vacuum to give phenylfluoroboron dipyrrole (0.68 g, yield: 34.5%). 1 H NMR (CDCl3, 600MHz) δ: 7.48 (d, J=9.0Hz, 3H), 7.28 (d, J=9.0Hz, 2H), 2.55 (d, J=9.0Hz, 6H) 1.37 (d, J=9.0Hz, 6H). 13C NMR (CDCl3, 150MHz) δ: 146.3, 134.9, 132, 128.4, 127.7, 126.2, 118.0, 116.0, 112.0, 11.0, 9.0.

[0033] (2) Preparation of intermediate diiodophenylfluoroboron dipyrrole

[0034] Phenylacetyl fluoroboron dipyrrole (500 mg, 1.54 mmol) was dissolved in 200 mL of dichloromethane solution. N-iodosuccinimide (NIS) (2.08 g, 9.24 mmol) was added in three portions over 10 min, and the mixture was stirred at room temperature for 7 h. The mixture was concentrated under reduced pressure, and the residue was extracted with 30 mL of water, washed with saturated brine, dried over anhydrous magnesium sulfate, filtered, concentrated, and purified by column chromatography to obtain diiodophenyl fluoroboron dipyrrole (795 mg, yield: 89%). 1 H NMR (CDCl3, 600MHz) δ: 7.52 (d, J=9.0Hz, 3H), 7.25 (d, J=9.0Hz, 2H), 2.65 (d, J=9.0Hz, 6H), 1.38 (d, J=9.0Hz, 6H). 13 CNMR (CDCl3, 150MHz): δ: 146.3, 134.9, 132.0, 128.4, 127.7, 126.2, 118.0, 116.0, 112.0, 5.0, 4.0.

[0035] (3) Preparation of intermediate bispyridylphenylfluoroboron dipyrrole

[0036] Diiodophenylfluoroboron dipyrrole (100 mg, 0.174 mmol) was dissolved in 60 mL of 1,4-dioxane. Pyridineboronic acid (85 mg, 0.70 mmol), cesium carbonate (226 mg, 0.70 mmol), 6 mL of water, and tetrakis(triphenylphosphine)palladium (50 mg, 0.043 mmol) were added sequentially. The reaction system was evacuated, purged with nitrogen, and heated to 100 °C. The mixture was stirred for 24 h. The organic solvent was removed under reduced pressure, and the mixture was extracted with 30 mL of water and dichloromethane. The extract was washed with saturated brine, dried over anhydrous magnesium sulfate, filtered, concentrated, and purified by column chromatography to obtain dipyridylphenylfluoroboron dipyrrole (61 mg, yield: 73%). 1 H NMR (CDCl3, 600MHz) δ: 8.63 (d, J=9.0Hz, 4H), 7.52 (d, J=9.0Hz, 3H), 7.11 (d, J=9.0Hz, 2H), 2.57 (d, J=9.0Hz, 6H), 1.34 (d, J=9.0Hz, 6H). 13C NMR (CDCl3, 150MHz): δ: 150.3, 146.3, 143.7, 134.9, 132.0, 128.4, 127.7, 126.2, 122.1, 118.0, 116.0, 112.0, 5.0, 4.0.

[0037] (4) Preparation of bifunctional electrochromic material BDP-V

[0038] Bispyridylphenylfluoroboronide dipyrrole (50 mg, 0.104 mmol) was dissolved in 50 mL of acetonitrile, and iodomethane (147 mg, 1.04 mmol) was added dropwise at room temperature. After the addition was complete, the temperature was slowly raised to 80 °C, and the reaction was stirred for 12 h under a nitrogen atmosphere. The solution was concentrated under reduced pressure and purified by column chromatography to give BDP-V (26 mg, yield: 48%). 1 H NMR (CDCl3, 600MHz) δ: 8.97 (d, J=9.0Hz, 4H), 8.09 (d, J=9.0Hz, 4H), 7.52 (d, J= 9.0Hz, 3H), 4.32 (d, J=9.0Hz, 6H), 2.61 (d, J=9.0Hz, 6H), 1.42 (d, J=9.0Hz, 6H). 13 C NMR (CDCl3, 150MHz): δ: 148.3, 142.5, 141.7, 134.9, 132.8, 128.4, 127.7, 126.2, 122.1, 118.4, 116.0, 112.6, 37.8, 5.0, 4.0.

[0039] Example 2:

[0040] Device fabrication and testing based on BDP-V, a bifunctional electrochromic material of violetin with a fluoroboron dipyrrole core:

[0041] A 20mm × 15mm ITO (indium tin oxide) conductive glass was used as a transparent conductive electrode. It was washed with detergent and then ultrasonically cleaned sequentially with deionized water, acetone, and ethanol for 10 minutes each. It was then treated in a UV ozone generator for 10 minutes. The treated ITO conductive glass was placed with its conductive surface facing up. A sarin membrane with a small hole in the right side was placed on top, ensuring that three sides of the sarin membrane were in contact with the edge of the ITO conductive glass, while the side with the small hole was spaced a certain distance from the edge of the ITO conductive glass. Another cleaned ITO conductive glass was then placed on the sarin membrane with its conductive surface facing down. Finally, the device was encapsulated using a press. A propylene carbonate solution containing 0.05M BDP-V, 0.05M ferrocene, and 0.5M tetrabutylammonium tetrafluoroborate was prepared as the electrochromic solution. A piece of foam was placed in a single-necked round-bottom flask as a substrate for the device. The cavity for preparing the bifunctional electrochromic and electrofluorescent device was placed on the foam substrate in the single-necked round-bottom flask. The flask was then evacuated and purged with nitrogen, and this process was repeated three times. Subsequently, the prepared electrochromic solution was dropped onto the pre-drilled holes in the sarin membrane, and the solution was injected into the device using a pressure difference. Finally, the pre-drilled holes were sealed using UV photopolymerization.

[0042] The electrochromic performance of the device prepared above was tested: when a voltage was applied, the device changed from light red to reddish brown, with an optical contrast of 85% at 521 nm, a coloring time of 1.2 s, and a fading time of 1.8 s.

[0043] The electrochromic performance of the prepared device was tested: When no voltage was applied, the electrochromic device exhibited yellow fluorescence under 365nm excitation light; when a voltage of 1.5V was applied, the fluorescence of the electrochromic device was quenched. The fluorescence spectrum of the device during operation was analyzed. Figure 4 As can be seen, the device exhibits a distinct fluorescence peak at 546 nm when no voltage is applied. When a voltage of 1.5V is applied to the device, the fluorescence peak at 521 nm disappears, and the fluorescence intensity decreases by 96%.

[0044] Cyclic stability tests were conducted on the device prepared above: the peak value of its redox current was measured using an electrochemical workstation. The results showed that after 2000 cycles, the peak value of the timing current of the electrochromic device did not change significantly.

Claims

1. A bifunctional electrochromic material based on fluorinated boron dipyrrole as a core, characterized in that, Chemical structural formula of Formula I: Formula I.

2. A method for preparing a violet-based bifunctional electrochromic material with a fluorinated boron dipyrrole core as described in claim 1, characterized in that, Includes the following steps: (1) Preparation of intermediate phenylfluoroboron dipyrrole: 2,4-dimethylpyrrole and benzaldehyde were dissolved in anhydrous dichloromethane. Under a nitrogen atmosphere, trifluoroacetic acid was added and the mixture was stirred at room temperature in the dark and allowed to react overnight. Then, 2,3-dichloro-5,6-dicyanobenzoquinone was added. Three hours later, triethylamine and boron trifluoride diethyl ether were added. After the reaction was completed, the solvent was evaporated, and water was added to the residue. The residue was extracted with dichloromethane and washed with saturated brine. The organic phase was collected, dried with anhydrous magnesium sulfate, and the organic solvent was removed under reduced pressure. The obtained solid was separated, purified, and dried under vacuum to obtain phenylfluoroboron dipyrrole. ; (2) Preparation of intermediate diiodophenylfluoroboron dipyrrole: Phenylfluoroboron dipyrrole was dissolved in anhydrous dichloromethane, and N-iodosuccinimide was added in portions. The mixture was stirred overnight at room temperature. After the reaction was completed, the mixture was concentrated under reduced pressure. Water was added to the residue, and the residue was extracted with dichloromethane. The residue was then washed with saturated brine, and the organic phase was collected. After drying with anhydrous magnesium sulfate, the solvent was evaporated. The obtained solid was separated and purified, and then dried under vacuum to obtain diiodophenylfluoroboron dipyrrole. ; (3) Intermediate bispyridylphenylfluoroboron dipyrrole: Diiodophenylfluoroboron dipyrrole was dissolved in 1,4-dioxane, and pyridine-4-boric acid, cesium carbonate aqueous solution, and tetrakis(triphenylphosphine)palladium were added sequentially. The temperature was slowly raised to 100°C under a nitrogen atmosphere and the reaction was maintained overnight. After the reaction was completed, the mixture was concentrated under reduced pressure, extracted with dichloromethane, washed with saturated brine, and the organic phase was collected. After drying with anhydrous magnesium sulfate, the solvent was evaporated, and the mixture was separated and purified. The product was then dried under vacuum to obtain bispyridylphenylfluoroboron dipyrrole. ; (4) Preparation of bifunctional electrochromic material BDP-V with fluorinated boron dipyrrole as core: Bispyridylphenyl fluorinated boron dipyrrole was dissolved in acetonitrile solution, iodomethane was added dropwise, the temperature was slowly raised to 80°C, the reaction was kept at the temperature under nitrogen atmosphere overnight, the solvent was removed under reduced pressure, the mixture was separated and purified, and vacuum dried to obtain bifunctional electrochromic material BDP-V with fluorinated boron dipyrrole as core.

3. The method for preparing a violet-based bifunctional electrochromic material with a fluoroboron dipyrrole core according to claim 2, characterized in that, In step (1), the molar ratio of 2,4-dimethylpyrrole, benzaldehyde, 2,3-dichloro-5,6-dicyanobenzoquinone, triethylamine and boron trifluoride diethyl ether is 2.5 : 1 : 1 : 15 :

15.

4. The method for preparing a violet-based bifunctional electrochromic material with a fluoroboron dipyrrole core according to claim 2, characterized in that, In step (2), the molar ratio of phenyl fluoroboron dipyrrole and N-iodosuccinimide is 1:

6.

5. The method for preparing a violet-based bifunctional electrochromic material with a fluoroboron dipyrrole core according to claim 2, characterized in that, In step (3), the molar ratio of diiodophenyl fluoroboron dipyrrole, pyridine-4-boronic acid, cesium carbonate and tetra(triphenylphosphine)palladium is 1:6:18:0.

1.

6. The method for preparing a violet-based bifunctional electrochromic material with a fluoroboron dipyrrole core according to claim 2, characterized in that, In step (4), the molar ratio of bispyridylphenylfluoroboron dipyrrole to iodomethane is 1:

6.

7. The application of the violet-based bifunctional electrochromic material with fluoroboron dipyrrole as its core as described in claim 1, characterized in that, Used for device fabrication; The specific preparation steps are as follows: (1) Cut the transparent ITO conductive glass substrate into a fixed size and perform etching, ultrasonic cleaning, and ultraviolet ozone treatment; place a piece of sarin film with a hollow center and a small hole on one side between two pieces of ITO conductive glass, and heat-shape it under a hot press to prepare the device. (2) A solution was prepared by dissolving BDP-V, a bifunctional electrochromic material of fluorine-boron dipyrrole as the core, ferrocene and tetrabutyltetrafluoroborate in N-methylpyrrolidone, and injected into the device under reduced pressure. The reserved small hole was then sealed with UV-cured adhesive.

8. The application according to claim 7, characterized in that, In the preparation step (2), the concentrations of BDP-V, ferrocene, and tetrabutylammonium tetrafluoroborate are 0.05 mol / L, 0.05 mol / L, and 0.1 mol / L, respectively.

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