Preparation and application of an anthraquinone-bridged terpyridine iron coordination polymer

Abstract

This invention discloses the preparation and application of an anthraquinone-bridged terpyridine iron coordination polymer. The organic iron coordination polymer material of this invention features a simple synthesis route, mild conditions, and low cost. Devices prepared using the anthraquinone-bridged terpyridine iron coordination polymer designed in this invention exhibit electrochromic functionality under applied voltage, and possess high optical contrast, fast response speed, and good cycling stability, demonstrating potential application value.

Description

Technical Field

[0001] This invention belongs to the field of organic optoelectronic functional materials technology, specifically relating to the preparation and application of a tripyridine iron coordination polymer based on anthraquinone bridging. Background Technology

[0002] Electrochromic materials are materials that change their optical properties in response to external electrical stimuli, reversibly switching between different redox states. Due to their unique photoelectric response characteristics, these materials are widely used in smart glass, anti-glare automotive rearview mirrors, smart filters, electrochromic displays, military camouflage, and thermal control. Currently, many types of electrochromic materials exist, among which transition metal coordination polymers combine the advantages of both organic and inorganic materials, thus attracting widespread attention and becoming a research hotspot. Among the many transition metal ions, ferrous ions (Fe2+) possess advantages such as low cost, good redox activity, and easy coordination with terpyridine, making them a focus of research on metal coordination polymer materials.

[0003] Anthraquinones and their derivatives possess excellent electrochromic properties. Therefore, their introduction into the terpyridine structural unit plays a crucial role in optimizing electronic structure, improving film-forming properties, regulating spectral absorption properties, enhancing electrochromic optical contrast, accelerating response rate, and improving coloring efficiency and cycle stability. Summary of the Invention

[0004] This invention designs and synthesizes an anthraquinone-bridged terpyridine-iron coordination polymer. The electrochromic material synthesized in this invention has a simple, mild, and low-cost synthesis route. Devices fabricated using the anthraquinone-bridged terpyridine-iron coordination polymer designed in this invention exhibit electrochromic functionality under applied voltage, and possess high optical contrast, fast response speed, and good cycling stability, demonstrating potential application value.

[0005] This invention provides a tripyridine iron coordination polymer material based on anthraquinone bridging, with the chemical structural formula (I):

[0006]

[0007] The method for synthesizing the anthraquinone-bridged tripyridine iron coordination polymer PAQTH-TPY is as follows: 2,6-dibromoanthraquinone is reacted with 3-n-hexylthiophene-2-boronic acid ester to prepare intermediate 1, which is then brominated with N-bromosuccinimide to generate intermediate 2. Intermediate 2 is then generated by a Suzuki coupling reaction with tripyridine boric acid to produce product AQTH-TPY. Finally, coordination polymerization is carried out with FeBF4·6H2O to obtain the final product PAQTH-TPY.

[0008] (1) 2,6-Dibromoanthraquinone (5 g, 13.66 mmol), 3-n-hexylthiophene-2-boronate (10.01 g, 40.98 mmol), sodium carbonate (8.69 g, 81.96 mmol), and tetra(triphenylphosphine)palladium (1.58 g, 1.366 mmol) were rapidly added sequentially to a 250 mL reaction flask. Then, 100 mL of toluene, 20 mL of distilled water, and 10 mL of water were added. The reaction was evacuated and purged with nitrogen under nitrogen protection at 90 °C for 24 h under reflux. 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 sodium sulfate, the organic solvent was removed under reduced pressure. The obtained solid was separated, purified, and dried under vacuum to obtain intermediate 1.

[0009] (2) Intermediate 1 (1g, 1.85mmol) and N-bromosuccinimide (NBS) (691.53mg, 3.885mmol) were dissolved in 30mL of DCM solution and reacted at room temperature for 12h. After the reaction was observed by TLC, the solvent was evaporated, then extracted, and finally obtained by column chromatography to obtain intermediate 2.

[0010] (3) Intermediate 2 (200 mg, 0.288 mmol), terpyridineboronic acid (406 mg, 1.152 mmol), potassium carbonate (318 mg, 2.304 mmol), and tetrakis(triphenylphosphine)palladium (33.2 mg, 0.0288 mmol) were rapidly added sequentially to a 100 mL reaction flask, followed by the addition of 40 mL of DMF solvent. The reaction was evacuated and purged with nitrogen at 100 °C for reflux for 24 h. After the reaction was complete, extraction was performed, and finally, AQTH-TPY was obtained by column chromatography.

[0011] (4) Dissolve AQTH-TPY and FeBF4·6H2O in a mixed solvent of CH2Cl2 / MeOH and reflux for 12 h under nitrogen protection at 60 °C. After the reaction is complete, cool the reaction mixture to room temperature, filter, and wash the filter cake successively with H2O, EtOH, and CH2Cl2 to obtain PAQTH-TPY.

[0012] The synthesis process is as follows:

[0013]

[0014]

[0015] In step (1), the molar ratio of 2,6-dibromoanthraquinone, 3-n-hexylthiophene-2-boronate, sodium carbonate and tetra(triphenylphosphine)palladium is 1:3:6:0.1, the reaction temperature is 90-100℃, and the reaction time is 20-24h.

[0016] In step (2), the molar ratio of intermediate 1 and N-bromosuccinimide is 1:2.1, and the reaction is carried out at room temperature for 10-12 hours.

[0017] In step (3), the molar ratio of intermediate 2, terpyridineboronic acid, potassium carbonate, and tetra(triphenylphosphine)palladium is 16:8:0.1, the reaction temperature is 90-95℃, and the reaction time is 20-24h.

[0018] In step (4), the molar ratio of AQTH-TPY and FeBF4·6H2O is 1:1.2, the reaction temperature is 60-70℃, and the reaction time is 10-12h.

[0019] The anthraquinone-bridged terpyridine iron coordination polymer PAQTH-TPY prepared according to this invention is applied to the fabrication of a device. The device consists of a transparent conductive substrate, an electrochromic layer, an electrolyte, and a metal electrode. The specific fabrication steps are as follows:

[0020] (1) Cut the transparent conductive substrate into appropriate sizes, clean the cut conductive substrate in a solvent by ultrasonic cleaning, and then treat it with ultraviolet ozone.

[0021] (2) Take a clean, transparent conductive substrate, with the conductive side facing up, and place it on a spin coater. Use a pipette to take 20 μL of N,N-dimethylformamide solution of iron coordination polymer onto the transparent conductive substrate, adjust the rotation speed to 1000 r / min, and spin coat continuously for 120 s on a spin coater. After spin coating, sinter the resulting film on an 80℃ heating plate for 10 min, dry it to remove excess solvent, and set it aside for later use.

[0022] (3) The metal electrodes are attached to both sides of the conductive substrate coated with electrochromic material using 3M tape. Then another transparent conductive substrate is attached to the electrochromic layer with metal electrodes, electrolyte is injected, and then hot melt adhesive is used for external sealing.

[0023] (4) Wrap conductive tape around the outer ends of the two pieces of conductive glass.

[0024] 8. The application according to claim 7, characterized in that,

[0025] (1) The transparent conductive substrate is one of ITO conductive glass, FTO conductive glass or flexible substrate;

[0026] (2) The concentration of the N,N-dimethylformamide solution of the iron coordination polymer is 80 mg / mL;

[0027] (3) The electrolyte is a 3 mol / L zinc perchlorate aqueous solution, and the metal electrode is zinc;

[0028] This invention has the following advantages:

[0029] The electrochromic material designed in this invention features a simple, mild, and low-cost synthesis route. Devices prepared using an anthraquinone-bridged terpyridine iron coordination polymer designed in this invention exhibit electrochromic functionality under applied voltage, and possess high optical contrast, fast response speed, and good cycling stability, demonstrating potential application value. Attached Figure Description

[0030] Figure 1 The molecular structure of PAQTH-TPY, an anthraquinone-bridged terpyridine iron coordination polymer synthesized in Example 1, is shown. Detailed Implementation

[0031] Example 1:

[0032] Synthesis of the electrochromic material PAQTH-TPY:

[0033]

[0034] (1) 2,6-Dibromoanthraquinone (5 g, 13.66 mmol), 3-n-hexylthiophene-2-boronate (10.01 g, 40.98 mmol), sodium carbonate (8.69 g, 81.96 mmol), and tetrakis(triphenylphosphine)palladium (1.58 g, 1.366 mmol) were rapidly added sequentially to a 250 mL reaction flask. Then, 100 mL of toluene, 20 mL of distilled water, and 10 mL of water were added. The reaction was evacuated and purged with nitrogen under nitrogen protection at 90 °C for reflux 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 sodium sulfate, the organic solvent was removed under reduced pressure. The obtained solid was separated, purified, and dried under vacuum to obtain intermediate 1 (4.58 g, yield: 62%). 1 H NMR (600MHz, CDCl3) δ8.52 (d, J=2.0Hz, 2H), 8.34 (d, J=8.1Hz, 2H), 7.99 (dd, J=8.1, 2.0Hz, 2H), 7.47 (d, J=1.4Hz, 2H ), 7.07 (q, J=1.1Hz, 2H), 2.68 (t, J=7.8Hz, 4H), 1.73-1.67 (m, 4H), 1.42-1.32 (m, 12H), 0.93 (td, J=5.8, 3.0Hz, 6H).

[0035] (2) Intermediate 1 (1 g, 1.85 mmol) and N-bromosuccinimide (691.53 mg, 3.885 mmol) were dissolved in 30 mL of DCM solution and reacted at room temperature for 12 h. After the reaction was observed by TLC, the solvent was evaporated, and then extracted and passed through a column to finally obtain intermediate 2 (0.98 g, yield: 76%). 1 H NMR (600MHz, CDCl3) δ8.44 (d, J=2.0Hz, 2H), 8.34 (d, J=8.1Hz, 2H), 7.90 (dd, J=8.1, 2.0Hz, 2H) , 7.32 (s, 2H), 2.66-2.61 (m, 4H), 1.67 (t, J=7.5Hz, 4H), 1.41-1.30 (m, 12H), 0.95-0.91 (m, 6H).

[0036] (3) Intermediate 2 (200 mg, 0.288 mmol), terpyridineboronic acid (406 mg, 1.152 mmol), potassium carbonate (318 mg, 2.304 mmol), and tetra(triphenylphosphine)palladium (33.2 mg, 0.0288 mmol) were rapidly added sequentially to a 100 mL reaction flask, followed by the addition of 40 mL of DMF solvent. The reaction was evacuated and purged with nitrogen at 100 °C for reflux for 24 h. After the reaction was completed, as monitored by TLC, extraction was performed, and finally, AQTH-TPY (235 mg, yield: 71%) was purified by column chromatography.

[0037] (4) AQTH-TPY and FeBF4·6H2O were dissolved in a mixed solvent of CH2Cl2 / MeOH and refluxed for 12 h at 60 °C under nitrogen protection. After the reaction was completed, the reaction mixture was cooled to room temperature, filtered, and the filter cake was washed successively with H2O, EtOH, and CH2Cl2 to obtain the iron coordination polymer PAQTH-TPY.

[0038] Example 2:

[0039] Fabrication and performance testing of electrochromic devices based on anthraquinone-bridged terpyridine-iron coordination polymer PAQTH-TPY:

[0040] (1) Preparation of anthraquinone-bridged terpyridine-iron coordination polymer PAQTH-TPY thin films

[0041] Cut the 1.5×2.5cm 2ITO (indium tin oxide) conductive glass of various sizes was ultrasonically cleaned for 15 min each with deionized water, acetone, and isopropanol, and then dried with nitrogen. 20 μL of an 80 mg / mL solution of the iron-coated polymer N,N-dimethylformamide was pipetted onto a piece of conductive glass. The spin coater was set to 1000 rpm and continuously spin-coated for 120 s. After spin-coating, the resulting film was sintered on an 80°C hot plate for 10 min and then dried to remove excess solvent.

[0042] (2) Fabrication of electrochromic devices

[0043] Zinc electrodes were attached to both sides of the spin-coated film using 3M tape. Another piece of cleaned conductive glass was placed with the conductive side facing up and attached to the film. A 3 mol / L zinc perchlorate aqueous solution was injected into the device as an electrolyte. The device was then encapsulated with hot melt adhesive and conductive tape was attached to both ends of the device.

Claims

1. A tripyridine-iron coordination polymer based on anthraquinone bridging, characterized in that, Chemical structural formula with formula (Ⅰ): Formula I.

2. The method for preparing an anthraquinone-bridged terpyridine iron coordination polymer according to claim 1, characterized in that, The process includes the following steps: 2,6-dibromoanthraquinone reacts with 3-n-hexylthiophene-2-boronic acid ester to prepare intermediate 1, which then undergoes a bromination reaction with N-bromosuccinimide to generate intermediate 2, followed by a Suzuki coupling reaction with terpyridineboronic acid to generate product AQTH-TPY, and finally coordination with FeBF4⋅6H2O to obtain polymer PAQTH-TPY; Formula II; (1) Preparation of intermediate 1: 2,6-dibromoanthraquinone (5 g, 13.66 mmol), 3-n-hexylthiophene-2-boronate (10.01 g, 40.98 mmol), sodium carbonate (8.69 g, 81.96 mmol), and tetrakis(triphenylphosphine)palladium (1.58 g, 1.366 mmol) were added to a 250 mL reaction flask in sequence. Then, 100 mL of toluene, 20 mL of distilled water and 10 mL of water were added. Under nitrogen protection, the reaction temperature was 90 °C and refluxed for 24 h. The reaction was observed by TLC. After the reaction was completed, the mixed solvent was evaporated, 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 sodium sulfate, the organic solvent was removed under reduced pressure. The obtained solid was separated and purified, and dried under vacuum to obtain intermediate 1. (2) Preparation of intermediate 2: Intermediate 1 (1 g, 1.85 mmol) and N-bromosuccinimide (NBS) (691.53 mg, 3.885 mmol) were dissolved in 30 mL of DCM solution and reacted at room temperature for 12 h. After the reaction was observed by TLC, the solvent was evaporated, then extracted, and the mixture was passed through a column to finally obtain intermediate 2. (3) Preparation of AQTH-TPY: Intermediate 2 (200 mg, 0.288 mmol), terpyridineboronic acid (406 mg, 1.152 mmol), potassium carbonate (318 mg, 2.304 mmol), and tetrakis(triphenylphosphine)palladium (33.2 mg, 0.0288 mmol) were added to a 100 mL reaction flask in sequence, followed by the addition of 40 mL of DMF solvent. The reaction was evacuated and purged with nitrogen at 100 °C and refluxed for 24 h. After the reaction was completed by TLC monitoring, extraction was performed, and finally AQTH-TPY was purified by column chromatography. (4) Preparation of PAQTH-TPY: AQTH-TPY and FeBF4⋅6H2O were dissolved in a mixed solvent of CH2Cl2 / MeOH. Under nitrogen protection, the reaction temperature was 60 °C and the mixture was refluxed for 12 h. After the reaction was completed, the reaction mixture was cooled to room temperature, filtered, and the filter cake was washed successively with H2O, EtOH, and CH2Cl2 to obtain PAQTH-TPY.

3. The method for preparing an anthraquinone-bridged terpyridine iron coordination polymer according to claim 2, characterized in that, In the synthesis method described above: in step (1), the molar ratio of 2,6-dibromoanthraquinone, 3-n-hexylthiophene-2-boronate, sodium carbonate, and tetra(triphenylphosphine)palladium is 1:3:6:0.1, the reaction temperature is 90~100 ℃, and the reaction time is 20~24 h; in step (2), the molar ratio of intermediate 1 and N-bromosuccinimide is 1:2.1, the reaction is carried out at room temperature, and the reaction time is 10-12 h; in step (3), the molar ratio of intermediate 2, terpyridineboronic acid, potassium carbonate, and tetra(triphenylphosphine)palladium is 1:6:8:0.1, the reaction temperature is 90~95 ℃, and the reaction time is 20~24 h; in step (4), the molar ratio of AQTH-TPY and FeBF4⋅6H2O is 1:1.2, the reaction temperature is 60~70, and the reaction time is 10~12 h.

4. The application of the anthraquinone-bridged terpyridine iron coordination polymer as described in claim 1 as an electrochromic material in electrochromic devices.

5. The application according to claim 4, characterized in that, The electrochromic device consists of a transparent conductive substrate, an electrochromic layer, an electrolyte, and a metal electrode. The specific steps are as follows: (1) Cut the transparent conductive substrate into appropriate sizes, clean the cut conductive substrate in a solvent using ultrasonic cleaning, and then treat it with ultraviolet ozone; (2) Take a clean transparent conductive substrate, place it with the conductive side facing up on a spin coater; use a pipette to take 20 µL of N,N-dimethylformamide solution of iron coordination polymer on the transparent conductive substrate, adjust the rotation speed to 1000 r / min, and spin coat it continuously for 120 s on a spin coater. After spin coating, sinter the obtained film on an 80 ℃ heating plate for 10 min, dry it to remove excess solvent, and set it aside for later use; (3) Adhere the metal electrode to both sides of the conductive substrate coated with electrochromic material using 3M tape, then adhere another transparent conductive substrate to the electrochromic layer with metal electrode, inject electrolyte, and then seal it with hot melt adhesive; (4) Wrap the conductive tape around both ends of the device.

6. The application according to claim 5, characterized in that: (1) The transparent conductive substrate is one of ITO conductive glass, FTO conductive glass or flexible substrate; (2) The concentration of the N,N-dimethylformamide solution of the iron coordination polymer is 80 mg / mL; (3) The electrolyte is a zinc perchlorate aqueous solution with a concentration of 3 mol / L, and the metal electrode is zinc.

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