Purpurine derivative as well as synthesis method and application thereof

Abstract

The invention relates to the technical field of photochemistry, in particular to a viologen derivative and a synthesis method and application thereof. The structural general formula is as shown in the formula: # imgabs0 #; wherein R1 and R2 both comprise one of alkyl, biphenyl and polyethylene oxide; x-comprises a monovalent anion. According to the invention, phosphorus is introduced into viologen molecules, and a formed polycyclic system not only effectively stabilizes free radicals of the viologen molecules in an oxidation state, but also avoids dimerization of the viologen molecules. Meanwhile, the original absorption wavelength of viologen molecules can be changed by adding the phosphorus element, so that the color of the product is adjusted, and the development of a multi-color electrochromic product is realized.

Description

Technical Field

[0001] The present invention relates to the field of photochemical technology, and more specifically to a viologen derivative and a synthesis method and application thereof. Background Art

[0002] In recent years, electrochromic materials used in electrochromic functional smart windows have received extensive attention as a new type of optoelectronic intelligent functional materials. This type of functional material can undergo reversible and obvious color changes under the action of a certain electric field, and has a significant regulating effect on ultraviolet-visible light and thermal infrared. 4,4'-bipyridine (viologen)-type color-changing materials have great industrial application prospects due to their strong structural designability, rich color changes and electrochemical stability. They can effectively realize a series of applications in smart windows (color-changing rearview mirrors, color-changing skylights); smart buildings (curtain wall glass, indoor glass); smart glasses (VR glasses, sunglasses). For chemical electrochromic technology, it is essentially due to the reversible redox reaction of the internal materials under the action of the electric field, and the corresponding products produce corresponding absorption of visible light of a certain wavelength, resulting in a change in color. Viologen / ferrocene system is a commonly used chemical molecule for chemical electrochromism. However, the traditional viologen molecule is not stable enough in its oxidized state, and it is easy to dimerize, resulting in irreversible reaction. Moreover, the color of the viologen molecule itself is relatively single, making it impossible to develop multi-color electrochromic products.

[0003] Chinese invention patent CN114967264A discloses an electrochromic gel. Although the response speed of the gel is fast, it needs to be further improved. The patent does not disclose the color stability of the electrochromic gel, and its color stability also needs to be further improved. Chinese invention patent CN115536578B discloses an aromatic ester substituted viologen electrochromic compound and its preparation method and application. The aromatic ester substituted viologen electrochromic compound can be used to prepare a gel electrolyte with a black electrochromic response. The device containing the gel electrolyte can not only achieve multi-level color regulation, but also achieve zero transmittance of the device in the visible light region, but its stability has not been studied. GENTEX reported the synthesis of large-volume viologen derivatives in the US invention patent US 20160229803A1 (Formula 1): 1; Ningbo Niruo Electronic Technology Co., Ltd., reported the synthesis of polyviologen derivatives in Chinese invention patent CN 111718291 A (Formula 2): 2; However, there is no report on the above-mentioned related patents regarding the introduction of phosphorus into viologen molecules to improve stability and improve the coloring and fading effects of electrochromic products. Summary of the invention

[0004] The first aspect of the present invention provides a viologen derivative, the general structural formula of which is shown in IV: IV; wherein R1 and R2 each include one of an alkyl group, a biphenyl group and a polyethylene oxide group; X - Includes monovalent anions.

[0005] Preferably, both R1 and R2 include one of an alkyl group with 1 to 20 carbon atoms, a biphenyl group with 1 to 20 benzene rings, and a polyethylene oxide group with a degree of polymerization of 1 to 10; X - Including F - , Cl - Br - ,I - 、BF4 - and PF6 - One of them.

[0006] The second aspect of the present invention provides a method for synthesizing a viologen derivative, and the reaction formula is shown in Formula 1 below: 1.

[0007] The present application found that the introduction of phosphorus into the interior of the viologen molecule can achieve multi-color electrochromism. It may be that the formed polycyclic system not only effectively stabilizes the free radicals in the oxidized state of the viologen molecule and prevents the occurrence of viologen dimerization, but also the addition of phosphorus can change the original absorption wavelength of the viologen molecule, thereby adjusting the color of the product.

[0008] The synthesis method of the viologen derivative comprises the following steps: S1, dissolving 3,3'-dibromobipyridine in a first solvent, adding a reactant, adding compound II after the reaction, continuing the reaction, quenching, and post-treating to obtain intermediate III; S2, dissolving the intermediate III and the compound R2X in a second solvent, reacting, and then post-treating to obtain the product.

[0009] Preferably, step S1 comprises: dissolving 3,3'-dibromobipyridine in a first solvent, adding a reactant at -85 to -70°C, reacting for 0.2 to 0.4 hours, adding compound II, continuing the reaction for 1 to 3 hours, quenching, and obtaining intermediate III through post-treatment.

[0010] Further preferably, the step S1 comprises: dissolving 3,3'-dibromobipyridine in a first solvent, adding a reactant at -82 to -75°C, reacting for 0.2 to 0.4 hours, adding compound II, continuing the reaction for 1 to 2 hours, quenching, and obtaining intermediate III through post-treatment.

[0011] Preferably, the reaction temperature in step S2 is 80-110° C. and the reaction time is 2-5 h.

[0012] More preferably, the reaction temperature in step S2 is 80-100° C. and the reaction time is 2-4 h.

[0013] The first solvent includes at least one of THF (tetrahydrofuran) and diethyl ether.

[0014] The reactant includes an alkyl lithium compound, including but not limited to at least one of methyl lithium, n-butyl lithium, and tert-butyl lithium.

[0015] The second solvent includes at least one of DMF (N,N-dimethylformamide), DMAc (N,N-dimethylacetamide), NMP (N-methylpyrrolidone), and DMSO (dimethyl sulfoxide).

[0016] A third aspect of the present invention provides an application of a viologen derivative as an electrochromic molecule in an electrochromic product formulation.

[0017] The electrochromic product formula comprises: 1-5 parts of electrochromic molecules, 0.5-3 parts of ferrocene compounds, 5-50 parts of electrolyte salts, and 2-50 parts of a third solvent.

[0018] Preferably, the electrochromic product formula includes: 1-4 parts of electrochromic molecules, 0.5-2.5 parts of ferrocene compounds, 10-50 parts of electrolyte salts, and 2-50 parts of a third solvent.

[0019] The electrochromic product formula also includes at least one of a thickener, a coupling agent, a UV stabilizer, and an antioxidant.

[0020] The ferrocene compounds include, but are not limited to, the following substances: ferrocene, ferrocene chloride, ferrocene bromide, ferrocene tetrafluoroborate, and ferrocene hexafluorophosphate.

[0021] Preferably, the ferrocene compound includes ferrocene and / or ferrocene hexafluorophosphate.

[0022] The electrolyte salt includes, but is not limited to, the following substances: 1-ethyl-3-methylimidazolium halogenated salt, bis(trifluoromethanesulfonic acid) imide lithium salt, bis(trifluoromethanesulfonic acid) imide sodium salt, bis(trifluoromethanesulfonic acid) imide tetramethylamine salt, bis(trifluoromethanesulfonic acid) imide tetraethylamine salt.

[0023] The third solvent includes, but is not limited to, the following substances: dimethylformamide, dimethylacetamide, N-methylpyrrolidone, tetrahydrofuran, ethyl acetate, ethylene carbonate, propylene carbonate, r-caprolactone, and r-butyrolactone.

[0024] Preferably, the third solvent comprises ethylene carbonate and / or propylene carbonate.

[0025] The thickener includes, but is not limited to, the following substances: polymethyl methacrylate, polyvinyl alcohol, polyethylene glycol, polyester, and polycarbonate.

[0026] The coupling agent includes but is not limited to the following substances: propyltriethoxysilane, allyltriethoxysilane, and hydroxypropyltriethoxysilane.

[0027] The ultraviolet stabilizer includes but is not limited to the following substances: butyl methoxydibenzoylmethane and 2,4-dihydroxybenzophenone.

[0028] The antioxidant includes, but is not limited to, the following substances: D-isoascorbic acid, 4-[(4,6-dioctylthio-1,3,5-triazine-2-yl)amino]-2,6-di-tert-butylphenol.

[0029] The electrochromic molecule is added in an amount of 2-5 wt % in the electrochromic product.

[0030] Preferably, the electrochromic molecule is added in an amount of 2.2-4.5 wt % in the electrochromic product.

[0031] Further preferably, the electrochromic molecule is added in an amount of 2.2-4.2 wt % in the electrochromic product.

[0032] Beneficial Effects 1. Introducing phosphorus into the interior of the violaceous molecule can achieve multi-color electrochromic properties.

[0033] 2. The stability of viologen molecules can be improved by synthesizing specific viologen derivatives.

[0034] 3. The synthesis method of the viologen derivatives of the present application is simple and the reaction conditions are mild.

[0035] 4. The coloring and fading effects of electrochromic products can be improved by selecting the electrochromic product formula.

[0036] 5. The addition amount of electrochromic molecules in electrochromic products is 2-5wt%, which can achieve excellent fading effect at a lower addition amount of electrochromic molecules. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is the H NMR spectrum of compound V1.

[0038] Figure 2 This is the H NMR spectrum of V2 compound.

[0039] Figure 3 This is the H NMR spectrum of V5 compound.

[0040] Figure 4The colors (blue-green) under the initial state and colored state conditions of the formula of Example 6, where the left picture corresponds to the initial state.

[0041] Figure 5 The colors (dark blue) under the initial state and colored state conditions of the formula of Example 8, wherein the upper figure corresponds to the initial state.

[0042] Figure 6 The colors (red) under the initial state and colored state conditions of the formula of Example 7, where the left picture corresponds to the initial state.

[0043] Figure 7 The colors (green) under the initial state and colored state conditions of the formula of Example 9, where the left picture corresponds to the initial state. DETAILED DESCRIPTION

[0044] Example 1 A viologen derivative, the structural formula of which is shown in Formula 5: 5.

[0045] A method for synthesizing a viologen derivative, the reaction formula of which is shown in Formula 6-7, comprises the following steps: S1 phosphorus participates in the synthesis of viologen precursors 6; Under anhydrous and oxygen-free conditions, 3,3'-dibromobipyridine was dissolved in anhydrous THF, n-butyl lithium was added at -78 degrees Celsius, and dichlorophenylphosphine was added after half an hour of reaction. The reaction was carried out at low temperature for 2 hours. Then methanol was added dropwise to quench the reaction. The product was washed twice with saturated brine, the organic phase was retained, and then the solvent was evaporated for column chromatography separation to finally obtain the product.

[0046] Synthesis of S2 Viologen Molecule 7; The above product and n-chlorohexane were dissolved in DMF and reacted at 100 degrees Celsius for 3 hours under anhydrous and oxygen-free conditions. After the reaction, the solvent was evaporated, the solid product was washed several times with cyclohexane, and dried to obtain the final product, which was named: V1.

[0047] An application of a viologen derivative as an electrochromic molecule in an electrochromic product formula, wherein the electrochromic product formula comprises: 2 g of a V1 compound, 1.5 g of a ferrocene compound (ferrocene), 10 g of an electrolyte salt (lithium bistrifluoromethanesulfonamide), and 50 g of a third solvent (propylene carbonate).

[0048] Embodiment 2: A viologen derivative, the structural formula of which is shown in Formula 8: 8; A method for synthesizing a viologen derivative, wherein the synthesis reaction formula is shown in Formula 9-10, comprises the following steps: S1 phosphorus participates in the synthesis of viologen precursors 9; Under anhydrous and oxygen-free conditions, 3,3'-dibromobipyridine was dissolved in anhydrous THF, n-butyl lithium was added at -78 degrees Celsius, and dichloromethyl phosphine was added after half an hour of reaction. The reaction was carried out at low temperature for 2 hours. Then methanol was added dropwise to quench the reaction. The product was washed twice with saturated brine, the organic phase was retained, and then the solvent was evaporated for column chromatography separation to finally obtain the product.

[0049] Synthesis of S2 Viologen Molecule 10; The above product and n-chlorohexane were dissolved in DMF and reacted at 100 degrees Celsius for 3 hours under anhydrous and oxygen-free conditions. After the reaction, the solvent was evaporated, the solid product was washed several times with cyclohexane, and dried to obtain the final product, which was named: V2.

[0050] Embodiment 3: A viologen derivative, the structural formula of which is shown in Formula 11: 11; A method for synthesizing a viologen derivative, wherein the synthesis reaction formula is shown in Formula 12, comprises the following steps: S1 phosphorus participates in the synthesis of viologen precursors 12; Under anhydrous and oxygen-free conditions, 3,3'-dibromobipyridine was dissolved in anhydrous THF, n-butyl lithium was added at -78 degrees Celsius, and dichloromethoxyphosphine was added after half an hour of reaction. The reaction was carried out at low temperature for 2 hours. Then methanol was added dropwise to quench the reaction. The product was washed twice with saturated brine, the organic phase was retained, and then the solvent was evaporated for column chromatography separation to finally obtain the product.

[0051] Synthesis of S2 Viologen Molecule The above product and n-chlorohexane were dissolved in DMF and reacted at 100 degrees Celsius for 3 hours under anhydrous and oxygen-free conditions. After the reaction, the solvent was evaporated, the solid product was washed several times with cyclohexane, and dried to obtain the final product, which was named: V3.

[0052] Embodiment 4: A viologen derivative, the structural formula of which is shown in Formula 13: 13; The product obtained in S1 of Example 1 was dissolved in chlorobenzene, heated to reflux under anhydrous and oxygen-free conditions, and reacted for 24 hours. After the reaction, the solvent was evaporated and dried to obtain the final product, which was named: V4.

[0053] Embodiment 5: A viologen derivative, the structural formula of which is shown in Formula 14: 14; The product V4 prepared in Example 4 was dissolved in dichloromethane, and AgBF4 was added after the dissolution was complete. The mixture was stirred overnight and then filtered. The residue was rinsed with dichloromethane twice, and the solution was combined and evaporated to dryness to obtain the final product, which was named V5.

[0054] Example 6 An application of a viologen derivative as an electrochromic molecule in an electrochromic product formula, wherein the electrochromic product formula comprises: 2 g of a V1 compound, 1.5 g of a ferrocene compound (ferrocene), 10 g of an electrolyte salt (lithium bistrifluoromethanesulfonamide), and 50 g of a third solvent (propylene carbonate).

[0055] Example 7 An application of a viologen derivative as an electrochromic molecule in an electrochromic product formula, wherein the electrochromic product formula includes: 2.2 g of a V3 compound, 3.2 g of a ferrocene compound (the weight ratio of ferrocene to ferrocene hexafluorophosphate is 2.2:1), 50 g of an electrolyte salt (lithium bistrifluoromethanesulfonate imide), and 2 g of a third solvent (propylene carbonate).

[0056] Example 8 An application of a viologen derivative as an electrochromic molecule in an electrochromic product formula, wherein the electrochromic product formula includes: 2 g of a V1 compound, 1.5 g of a ferrocene compound (ferrocene), 10 g of an electrolyte salt (lithium bis(trifluoromethanesulfonyl)imide), 50 g of a third solvent (propylene carbonate), and 20 g of a thickener (polymethyl methacrylate).

[0057] Example 9 An application of a viologen derivative as an electrochromic molecule in an electrochromic product formula, wherein the electrochromic product formula includes: 2 g of a V1 compound, 1.5 g of a ferrocene compound (ferrocene), 10 g of an electrolyte salt (lithium bistrifluoromethanesulfonamide), 50 g of a third solvent (propylene carbonate), 20 g of a thickener (polymethyl methacrylate), and 0.1 g of a UV stabilizer (2,4-dihydroxybenzophenone).

[0058] Example 10 An application of a viologen derivative as an electrochromic molecule in an electrochromic product formula, wherein the electrochromic product formula includes: 2 g of a V1 compound, 1.5 g of a ferrocene compound (ferrocene), 10 g of an electrolyte salt (lithium bis(trifluoromethanesulfonyl)imide), 50 g of a third solvent (propylene carbonate), 20 g of a thickener (polymethyl methacrylate), and 0.1 g of an antioxidant (D-isoascorbic acid).

[0059] Performance testing methods and data 1. The compounds synthesized in Examples 1, 2 and 5 were subjected to H NMR spectrum analysis. Figure 1-3 As shown, the synthesis of the above compounds can be judged.

[0060] 2. Prepare and apply the electrochromic products according to the formulas of Examples 6, 7, 8 and 9, such as Figure 4 , 5 , 6, and 7, electrochromic can be achieved. Among them, the application method of the formula of Example 6: inject the formula of Example 6 into a 100×100mm glass device prepared by ITO glass, and then seal the frame with glue. After the glue is cured, a 0.8V DC power supply is used for product testing. The application method of the formula of Example 8: inject the formula of Example 8 into a 50×250mm glass device prepared by ITO glass, and then seal the frame with glue. After the glue is cured, a 0.8V DC power supply is used for product testing. The application method of the formula of Example 7: inject the formula of Example 7 into a 50×50mm glass device prepared by ITO glass, and then seal the frame with glue. After the glue is cured, a 0.8V DC power supply is used for product testing. The application method of the formula of Example 9: inject the formula of Example 9 into a 50×50mm glass device prepared by ITO glass, and then seal the frame with glue. After the glue is cured, a 0.8V DC power supply is used for product testing.

Claims

1. A viologen derivative, characterized in that The general structural formula is shown in Formula IV: Ⅳ; wherein R1 and R2 each include one of an alkyl group, a biphenyl group and a polyethylene oxide group; X - Includes monovalent anions.

2. The viologen derivative according to claim 1, characterized in that Said R1 and R2 both include one of an alkyl group with 1 to 20 carbon atoms, a biphenyl with 1 to 20 benzene rings and a polyethylene oxide with a degree of polymerization of 1 to 10; X - Including F - , Cl - Br - ,I - 、BF4 - and PF6 - One of them.

3. A method for synthesizing the viologen derivative according to claim 1 or 2, characterized in that: The reaction formula is shown in Formula 1: 1。 4. The method for synthesizing the viologen derivative according to claim 3, characterized in that: The following steps are involved: S1, dissolving 3,3'-dibromobipyridine in a first solvent, adding a reactant, adding compound II after the reaction, continuing the reaction, quenching, and post-treating to obtain intermediate III; S2, dissolving the intermediate III and the compound R2X in a second solvent, reacting, and then post-treating to obtain the product.

5. The method for synthesizing the viologen derivative according to claim 4, characterized in that: The step S1 comprises: dissolving 3,3'-dibromobipyridine in a first solvent, adding a reactant at -85--70°C, reacting for 0.2-0.4h, adding compound II, continuing the reaction for 1-3h, quenching, and post-treating to obtain intermediate III.

6. The method for synthesizing a viologen derivative according to claim 5, characterized in that: The reaction temperature in step S2 is 80-110° C. and the reaction time is 2-5 hours.

7. A use of the viologen derivative according to claim 1 or 2, characterized in that: Used as an electrochromic molecule in the formulation of electrochromic products.

8. The use of the viologen derivative according to claim 7, characterized in that: In parts by weight, the electrochromic product formula includes: 1-5 parts of electrochromic molecules, 0.5-3 parts of ferrocene compounds, 5-50 parts of electrolyte salts, and 2-50 parts of a third solvent.

9. The use of the viologen derivative according to claim 8, characterized in that: The electrochromic product formula also includes at least one of a thickener, a coupling agent, a UV stabilizer, and an antioxidant.

10. The use of the viologen derivative according to claim 9, characterized in that: The electrochromic molecule is added in an amount of 2-5 wt % in the electrochromic product.

Images