Preparation method and application of a carbazole-grafted metal complex monomer and its polymer film

Abstract

The present invention belongs to the field of electrochromic technology and provides a method for preparing a carbazole-grafted metal complex monomer and a polymer film thereof and its application. The preparation of the monomer comprises the following steps: mixing a carbazole monomer (1), a bromine-substituted alkane, an inorganic base A, a phase transfer catalyst and an organic solvent A, and reacting to obtain a monomer (2); mixing the monomer (2), p-hydroxybenzaldehyde, an inorganic base A, a phase transfer catalyst and an organic solvent A, and reacting to obtain a monomer (3); mixing the monomer (3), 2-acetylpyridine, an inorganic base B, an amine source and an organic solvent B, and reacting to obtain a monomer (4); and mixing the monomer (4), an inorganic base C and an organic solvent C, and reacting to obtain a carbazole-grafted metal complex monomer (5). The present invention uses electrochemical polymerization of the monomer to prepare an electrochromic film, which can achieve multiple color changes under different voltages and can be applied to fields such as displays or mobile phone cases.

Description

Technical Field

[0001] The present invention relates to the technical field of electrochromism, and in particular to a carbazole-grafted metal complex monomer and a preparation method and application of a polymer film thereof. Background Art

[0002] "Electrochromism" (EC) refers to the phenomenon that the optical properties of a material, such as transmission, reflection, and absorption, undergo a stable and reversible redox reaction under the action of an external electric field, which manifests as a reversible change in color and transparency on a macroscopic scale. Therefore, electrochromic materials have gradually attracted widespread attention as a new type of functional material. Metal complexes, as an important component of high-performance electrochromic materials, are expected to be applied in recent years. Current researchers have been committed to solving the problem of preparing metal complexes into thin films, because this problem limits the further development of electrochromic materials. At present, the above-mentioned problems of metal complex electrochromic materials are usually solved by preparing hyperbranched metal complex polymer (supramolecular) structures to improve the adhesion of molecules to conductive substrates; or by using the liquid-liquid interface method to grow and prepare polymer films and extending the polymer to the conductive substrate by salvaging. However, the above two methods have technical problems such as high cost, difficulty and limited application range.

[0003] Therefore, how to provide a simple, low-cost method for preparing electrochromic thin films has become an urgent problem that needs to be solved by those skilled in the art. Summary of the Invention

[0004] In view of this, the present invention provides a carbazole-grafted metal complex monomer and a preparation method and application of the polymer film thereof, the purpose of which is to solve the technical problem that metal complexes are difficult to prepare into films.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] The present invention provides a carbazole-grafted metal complex monomer, the structural formula of which is as follows:

[0007]

[0008] in, Each of the alkanes is independently C1 to C10.

[0009] The present invention provides a method for preparing the above-mentioned carbazole-grafted metal complex monomer, comprising the following steps:

[0010] S1, mixing a carbazole monomer (1), a bromine-substituted alkane, an inorganic base A, a phase transfer catalyst, and an organic solvent A, and reacting the mixture to obtain a monomer (2);

[0011] S2, mixing monomer (2), p-hydroxybenzaldehyde, inorganic base A, phase transfer catalyst and organic solvent A and reacting to obtain monomer (3);

[0012] S3, mixing monomer (3), 2-acetylpyridine, inorganic base B, amine source and organic solvent B and reacting to obtain monomer (4);

[0013] S4, mixing the monomer (4), the inorganic base C and the organic solvent C and reacting them to obtain the carbazole-grafted metal complex monomer (5);

[0014] The structural formulas of the carbazole monomer (1), monomer (2), monomer (3), monomer (4) and metal complex monomer (5) are as follows:

[0015]

[0016] The value of m in the metal complex monomer (5) ranges from 10 to 100.

[0017] Furthermore, in step S1, the molar ratio of the carbazole monomer (1), the bromine-substituted alkane, the inorganic base A, the phase transfer catalyst and the organic solvent A is 1-2:2-5:0.3-1:0.5-5:20-40; the reaction temperature is 60-160° C., and the reaction time is 6-72 h;

[0018] The bromine-substituted alkane is any alkane of C1 to C10 substituted with a bromine;

[0019] The inorganic base A is one or more of potassium carbonate, sodium carbonate, cesium carbonate, potassium bicarbonate and sodium bicarbonate;

[0020] The phase transfer catalyst is one or more of 18-crown ether-6, tetrabutylammonium bromide and tetrabutylammonium iodide;

[0021] The organic solvent A is one or more of ethanol, acetone, dimethylformamide and acetonitrile.

[0022] Furthermore, in step S2, the molar ratio of monomer (2), p-hydroxybenzaldehyde, inorganic base A, phase transfer catalyst and organic solvent A is 0.5-2:1-5:0.3-1:0.5-5:20-40; the reaction temperature is 60-160°C, and the reaction time is 6-72h.

[0023] Furthermore, in step S3, the molar ratio of monomer (3), 2-acetylpyridine, inorganic base B, amine source and organic solvent B is 0.5-2:2-5:0.5-1.5:0.5-5:20-40; the reaction temperature is 0-80°C, and the reaction time is 48-96h;

[0024] The inorganic base B is one or more of sodium hydroxide, potassium hydroxide and calcium hydroxide;

[0025] The amine source is one or more of ammonium chloride, ammonia water and ammonia gas;

[0026] The organic solvent B is one or more of ethanol, methanol and tetrahydrofuran.

[0027] Furthermore, in step S4, the inorganic base is one or more of ferrous chloride, ferrous tetrafluoroborate and ferrous acetate;

[0028] The molar ratio of the monomer (4), the iron ions in the inorganic base C, and the organic solvent C is 1-2:0.8-1.5:20-40;

[0029] The reaction temperature is 0-50° C., and the reaction time is 1-8 hours.

[0030] The present invention provides a method for generating a polymer film from the above-mentioned carbazole-grafted metal complex monomer, comprising the following steps:

[0031] The metal complex monomer grafted with carbazole is added to an electrolyte to obtain a mixed solution, and the mixed solution is subjected to electrochemical cyclic voltammetry to obtain a polymer film;

[0032] The concentration of the carbazole-grafted metal complex monomer in the mixed solution is 1 to 10 mmol / L.

[0033] Furthermore, the electrolyte is a mixed solvent of acetonitrile and dichloromethane, and the volume ratio of acetonitrile to dichloromethane is 1:1-5;

[0034] The parameters of the electrochemical cyclic voltammetry are as follows: the electrolyte is one or more of tetrabutylammonium perchlorate, tetrabutylammonium hexafluorophosphate and lithium perchlorate; the working electrode is any one of ITO glass, FTO glass, ITO-PET substrate and FTO-PET substrate; the counter electrode is a platinum wire; the scanning speed is 100-150 mV / s; the voltage is 0-2 V; and the number of cycles is 20-40.

[0035] The present invention provides a polymer film prepared by the method.

[0036] The present invention provides applications of the polymer film in displays, smart windows or mobile phone cases.

[0037] It can be seen from the above technical solution that compared with the prior art, the beneficial effects of the present invention are as follows:

[0038] (1) The carbazole-grafted metal complex monomer provided by the present invention has good solubility in common organic solvents and can be directly prepared into a polymer film on a substrate by electrochemical direct polymerization, thus solving the technical problem of the difficulty in forming a film of a metal complex material on a substrate;

[0039] (2) The polymer film prepared by the present invention can achieve a stable and reversible transition from neutral red to blue, and has good applications in displays, smart windows or mobile phone cases;

[0040] (3) The present invention prepares a polymer film by cyclic voltammetry, using grafted carbazole as the electropolymerization group and a metal complex as the central group. Thanks to the alkyl chain between the grafted carbazole and the central complex, the conjugation effect between the carbazole and the central metal complex can be interrupted, reducing the effect of dipolymerized carbazole on the electrochromic properties of the metal complex, and allowing the metal complex to directly form a film on the electrode surface through the electrochemical reaction of carbazole. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is the hydrogen nuclear magnetic resonance spectrum of the carbazole-grafted metal complex monomer prepared in Example 1;

[0042] Figure 2 This is the hydrogen nuclear magnetic resonance spectrum of the carbazole-grafted metal complex monomer prepared in Example 2;

[0043] Figure 3 This is a polymerization curve diagram of the process of preparing a metal complex thin film by electrochemical cyclic voltammetry in Example 3;

[0044] Figure 4 This is an infrared absorption spectrum of the metal complex film prepared by electrochemical cyclic voltammetry in Example 3;

[0045] Figure 5 The UV absorption spectra of the polymer film prepared in Example 3 at multiple potentials ranging from 0 to 1.5 V at a wavelength of 300 to 1100 nm;

[0046] Figure 6 is a graph showing the change in transmittance of the polymer film prepared in Example 3 over time under step conditions;

[0047] Figure 7 This is a specific application diagram of a device made from the polymer film prepared in Example 3. DETAILED DESCRIPTION

[0048] The present invention provides a carbazole-grafted metal complex monomer, the structural formula of which is as follows:

[0049]

[0050] in, It is independently any one of C1 to C10 alkanes, preferably any one of C3 to C7 alkanes, and more preferably n-butane, n-pentane or n-hexane.

[0051] The present invention provides a method for preparing the above-mentioned carbazole-grafted metal complex monomer, comprising the following steps:

[0052] S1, mixing a carbazole monomer (1), a bromine-substituted alkane, an inorganic base A, a phase transfer catalyst, and an organic solvent A, and reacting the mixture to obtain a monomer (2);

[0053] S2, mixing monomer (2), p-hydroxybenzaldehyde, inorganic base A, phase transfer catalyst and organic solvent A and reacting to obtain monomer (3);

[0054] S3, mixing monomer (3), 2-acetylpyridine, inorganic base B, amine source and organic solvent B and reacting to obtain monomer (4);

[0055] S4, mixing the monomer (4), the inorganic base C and the organic solvent C and reacting them to obtain the carbazole-grafted metal complex monomer (5);

[0056] The structural formulas of the carbazole monomer (1), monomer (2), monomer (3), monomer (4) and metal complex monomer (5) are as follows:

[0057]

[0058] The value of m in the metal complex monomer (5) ranges from 10 to 100, preferably from 20 to 80, and more preferably from 40 to 60.

[0059] In the present invention, in step S1, the molar ratio of carbazole monomer (1), bromine-substituted alkane, inorganic base A, phase transfer catalyst and organic solvent A is 1-2:2-5:0.3-1:0.5-5:20-40, preferably 1:3-4:0.4-0.8:1-4:25-35, and more preferably 1:4:0.5:2.5:30; the reaction temperature is 60-160°C, preferably 80-150°C, and more preferably 100-120°C; the reaction time is 6-72h, preferably 10-60h, and more preferably 20-40h.

[0060] In the present invention, the bromine-substituted alkane is a bromine-substituted C1-C10 alkane, preferably a bromine-substituted C3-C7 alkane, and more preferably n-bromobutane, n-bromopentane or n-bromohexane;

[0061] The inorganic base A is one or more of potassium carbonate, sodium carbonate, cesium carbonate, potassium bicarbonate and sodium bicarbonate, preferably one or more of potassium carbonate, sodium carbonate, potassium bicarbonate and sodium bicarbonate, more preferably one or more of potassium carbonate, sodium carbonate and sodium bicarbonate;

[0062] The phase transfer catalyst is one or more of 18-crown ether-6, tetrabutylammonium bromide and tetrabutylammonium iodide, preferably tetrabutylammonium bromide and / or tetrabutylammonium iodide, more preferably tetrabutylammonium bromide;

[0063] The organic solvent A is one or more of ethanol, acetone, dimethylformamide and acetonitrile, preferably one or more of ethanol, acetone and acetonitrile, more preferably acetone and / or acetonitrile.

[0064] In the present invention, in step S1, after the reaction is completed, the reaction product is poured into water, extracted with dichloromethane, separated, separated and purified using a silica gel column chromatography, and dried to obtain monomer (2).

[0065] In the present invention, in step S2, the molar ratio of monomer (2), p-hydroxybenzaldehyde, inorganic base A, phase transfer catalyst and organic solvent A is 0.5-2:1-5:0.3-1:0.5-5:20-40, preferably 0.8-1.5:1.5-4:0.4-0.7:1-4:25-35, and more preferably 1:2-3:0.5:2.5:30; the reaction temperature is 60-160°C, preferably 80-150°C, and more preferably 100-120°C; and the reaction time is 6-72h, preferably 10-60h, and more preferably 20-40h.

[0066] In the present invention, in step S2, after the reaction is completed, the reaction product is poured into water, extracted with dichloromethane, separated, separated and purified using a silica gel column chromatography, and dried to obtain monomer (3).

[0067] In the present invention, in step S3, the molar ratio of monomer (3), 2-acetylpyridine, inorganic base B, amine source and organic solvent B is 0.5-2:2-5:0.5-1.5:0.5-5:20-40, preferably 0.8-1.5:3-4:0.8-1.2:1-4:25-35, more preferably 1:4:1:2:30; the reaction temperature is 0-80°C, preferably 20-60°C, more preferably 40-50°C; the reaction time is 48-96h, preferably 50-90h, more preferably 60-70h;

[0068] The inorganic base B is one or more of sodium hydroxide, potassium hydroxide and calcium hydroxide, preferably sodium hydroxide and / or potassium hydroxide, more preferably sodium hydroxide;

[0069] The amine source is one or more of ammonium chloride, ammonia water and ammonia gas, preferably ammonium chloride and / or ammonia water, more preferably ammonium chloride;

[0070] The organic solvent B is one or more of ethanol, methanol and tetrahydrofuran, preferably ethanol and / or methanol, more preferably methanol.

[0071] In the present invention, in step S3, after the reaction is completed, the reaction product is poured into water, extracted with dichloromethane, recrystallized and purified using dichloromethane and petroleum ether, and dried to obtain monomer (4).

[0072] In the present invention, in step S4, the inorganic base is one or more of ferrous chloride, ferrous tetrafluoroborate and ferrous acetate, preferably ferrous chloride and / or ferrous tetrafluoroborate, more preferably ferrous chloride;

[0073] The molar ratio of monomer (4), iron ions in inorganic base C, and organic solvent C is 1-2:0.8-1.5:20-40, preferably 1:1.0-1.4:25-35, and more preferably 1:1.1:30;

[0074] The reaction temperature is 0-50°C, preferably 20-40°C, more preferably 30°C; the reaction time is 1-8h, preferably 2-6h, more preferably 3-4h.

[0075] In the present invention, in step S4, after the reaction is completed, the reaction product is poured into petroleum ether, and recrystallized using dichloromethane and petroleum ether, and filtered, separated and purified to obtain a carbazole-grafted metal complex monomer (5).

[0076] The present invention provides a method for generating a polymer film from the above-mentioned carbazole-grafted metal complex monomer, comprising the following steps:

[0077] The metal complex monomer grafted with carbazole is added to an electrolyte to obtain a mixed solution, and the mixed solution is subjected to electrochemical cyclic voltammetry to obtain a polymer film;

[0078] The concentration of the carbazole-grafted metal complex monomer in the mixed solution is 1 to 10 mmol / L, preferably 2 to 8 mmol / L, and more preferably 5 to 6 mmol / L.

[0079] In the present invention, the electrolyte is a mixed solvent of acetonitrile and dichloromethane, and the volume ratio of acetonitrile to dichloromethane is 1:1-5, preferably 1:2-4, and more preferably 1:3;

[0080] The parameters of the electrochemical cyclic voltammetry are as follows: the electrolyte is one or more of tetrabutylammonium perchlorate, tetrabutylammonium hexafluorophosphate and lithium perchlorate, preferably tetrabutylammonium hexafluorophosphate and / or lithium perchlorate, and more preferably tetrabutylammonium hexafluorophosphate; the working electrode is any one of ITO glass, FTO glass, ITO-PET substrate and FTO-PET substrate, preferably any one of ITO glass, ITO-PET substrate and FTO-PET substrate, and more preferably ITO-PET substrate or FTO-PET substrate; the counter electrode is a platinum wire; the scanning speed is 100-150 mV / s, preferably 110-140 mV / s, and more preferably 120-130 mV / s; the voltage is 0-2 V, preferably 0.1-1.6 V, and more preferably 0.5-1.2 V; the number of cycles is 20-40, and preferably 30.

[0081] The present invention provides a polymer film prepared by the method.

[0082] The present invention provides applications of the polymer film in displays, smart windows or mobile phone cases.

[0083] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0084] Example 1

[0085] The preparation of the carbazole-grafted metal complex monomer comprises the following steps:

[0086] Carbazole monomer (1), 1,4-dibromobutane, potassium carbonate, 18-crown ether-6 and ethanol were mixed in a molar ratio of 1:4:0.5:2.5:30, and then reacted at 90°C for 12 hours. After the reaction, the reaction product was poured into water, extracted with dichloromethane, separated, separated and purified by silica gel chromatography, and dried to obtain monomer (2), with a conversion rate of 60%;

[0087] The monomer (2), p-hydroxybenzaldehyde, potassium carbonate, tetrabutylammonium bromide and acetone were mixed in a molar ratio of 1:2:0.5:2.5:30, and then reacted at 80°C for 14 hours. After the reaction, the reaction product was poured into water, extracted with dichloromethane, separated, separated and purified by silica gel chromatography, and dried to obtain monomer (3), with a conversion rate of 75%;

[0088] Monomer (3), 2-acetylpyridine, potassium hydroxide, ammonium chloride and tetrahydrofuran were mixed in a molar ratio of 1:4:1:2:30, and then reacted at 30°C for 50 hours. After the reaction, the reaction product was poured into water, extracted with dichloromethane, recrystallized and purified with petroleum ether, and dried to obtain monomer (4), with a conversion rate of 66%;

[0089] Monomer (4), ferrous chloride and dichloromethane were mixed in a molar ratio of 1:1.1:30, and then reacted at 30°C for 2 hours. After the reaction, the reaction product was poured into water, extracted with dichloromethane, recrystallized and purified with petroleum ether, and dried to obtain monomer (5), with a conversion rate of 80%.

[0090] Figure 1 The hydrogen nuclear magnetic resonance spectrum of the carbazole-grafted metal complex monomer prepared in this example is shown in FIG. Figure 1 It can be seen that 1H (500MHz) δ8.76–8.80 (s, 1H), 8.70–8.76 (s, 1H), 8.68–8.70 (d, J=8.1, 1.1Hz, 1H), 8.22–8.15 (d, J=8.2, 6.3Hz, 2H), 7.97–7.91 (t, J=7.7, 1.8Hz, 1H), 7.80–7.74 (d, J=8.4 Hz,1H),7.56–7.49(s,1H),7.49–7.45(d,J=8.2,1.3Hz,1H),7.44–7.39(d,J=7.5,4.8,1 .3Hz,1H),7.38–7.32(s,1H),6.52–6.58(s,1H),4.45-4.50(m,8H),1.31–1.24(s,16H).

[0091] Example 2

[0092] The preparation of the carbazole-grafted metal complex monomer comprises the following steps:

[0093] Carbazole monomer (1), 1,6-dibromohexane, sodium bicarbonate, tetrabutylammonium iodide and acetonitrile were mixed in a molar ratio of 1:2:0.5:2.6:30, and then reacted at 80°C for 16 hours. After the reaction, the reaction product was poured into water, extracted with dichloromethane, separated, separated and purified by silica gel chromatography, and dried to obtain monomer (2), with a conversion rate of 72%;

[0094] The monomer (2), p-hydroxybenzaldehyde, sodium carbonate, tetrabutylammonium bromide and dimethylformamide were mixed in a molar ratio of 1:1.5:0.5:2.2:30, and then reacted at 70°C for 15 hours. After the reaction, the reaction product was poured into water, extracted with dichloromethane, separated, separated and purified by silica gel chromatography, and dried to obtain monomer (3), with a conversion rate of 68%;

[0095] Monomer (3), 2-acetylpyridine, sodium hydroxide, aqueous ammonia and methanol were mixed in a molar ratio of 1:2.5:1.2:2:30, and then reacted at 30°C for 60 hours. After the reaction, the reaction product was poured into water, extracted with dichloromethane, and purified by recrystallization with petroleum ether and dried to obtain monomer (4), with a conversion rate of 59%;

[0096] Monomer (4), ferrous tetrafluoroborate and chloroform were mixed in a molar ratio of 1:1.5:30, and then reacted at 30°C for 2 hours. After the reaction, the reaction product was poured into water, extracted with dichloromethane, and purified by recrystallization with petroleum ether and dried to obtain monomer (5). The conversion rate was 77%.

[0097] Figure 2 The hydrogen nuclear magnetic resonance spectrum of the carbazole-grafted metal complex monomer prepared in this example is shown in FIG. Figure 2 It can be seen that 1H (500MHz) δ8.780–8.82 (s, 1H), 8.72–8.76 (s, 1H), 8.68–8.72 (d, J=8.1, 1.1Hz, 1H), 8.22–8.15 (d, J=8.2, 6.3Hz, 2H), 7.97–7.91 (t, J=7.7, 1.8Hz, 1H), 7.80–7.74 (d, J=8.4Hz, 1H), 7.56–7.49 (s, 1H), 7.49–

[0098] 7.45(d,J=8.2,1.3Hz,1H),7.44–7.39(d,J=7.5,4.8,1.3Hz,1H),7.38– 7.32(s,1H),6.52–6.58(s,1H),4.45-4.50(m,8H),1.31–1.24(s,24H).

[0099] Example 3

[0100] The carbazole-grafted metal complex monomer prepared in Example 1 was dissolved in an electrolyte (acetonitrile and dichloromethane in a volume ratio of 1:2) to form a mixed solution with a concentration of 5 mmol / L. Tetrabutylammonium perchlorate was added, an ITO glass substrate was used as a working electrode, a platinum wire was used as a counter electrode, the voltage was 1 V, and the scan rate was 100 mV / s. The number of cycles of electrochemical polymerization film formation by cyclic voltammetry was 20 to obtain a polymer film. The polymer film was washed in a mixed solvent of dichloromethane and acetonitrile to remove unpolymerized monomers or oligomers on the surface and residual electrolyte, and then placed in a watch glass to dry naturally for use.

[0101] Figure 3 The polymerization curve of the metal complex film prepared by electrochemical cyclic voltammetry in this embodiment is shown in FIG. Figure 3 It can be seen that with the increase in the number of electrochemical cycles, the electrochemical signal of the film in the figure gradually increases, and its peak current in the range of 1.4 to 1.6 V is significantly enhanced, which indicates that the monomer is gradually deposited on the electrode surface, thereby outputting a stronger electrochemical signal.

[0102] Figure 4 This is the infrared absorption spectrum of the metal complex film prepared by electrochemical cyclic voltammetry in this example. Figure 4 It can be seen that the complex monomer undergoes an electrochemical reaction to generate dicarbazole and deposits on the film, forming a stable metal complex polymer.

[0103] Figure 5 The UV absorption spectrum of the polymer film prepared in this example at multiple potentials within the range of 0 to 1.5 V at a wavelength of 300 to 1100 nm is shown in FIG. Figure 5 It can be seen that as the voltage is applied from 0V to 1.5V, the ultraviolet absorption peak of the polymer film at 575nm decreases significantly, which is due to the Fe 2+ Gradually oxidized to Fe 3+ The absorption of the film gradually increases after 800 nm, which is caused by the electrochemical oxidation of the dicarbazole unit.

[0104] Figure 6 is a curve diagram of the change of transmittance of the polymer film prepared in this embodiment with time under step conditions, Figure 6 It can be seen that when a cyclic step voltage is applied to the film, its transmission curve at 575nm shows a reciprocating step change. This is because the step voltage causes the polymer to undergo continuous redox reactions, resulting in a reversible color change of the film.

[0105] Figure 7 This is a specific application diagram of the device prepared by the polymer film prepared in Example 3, Figure 7It can be seen that the color changes under different voltages, indicating its practicality.

[0106] Example 4

[0107] The carbazole-grafted metal complex monomer prepared in Example 2 was dissolved in an electrolyte (the volume ratio of acetonitrile and dichloromethane was 1:3) to form a mixed solution with a concentration of 6 mmol / L. Lithium perchlorate was added, an FTO glass substrate was used as a working electrode, a platinum wire was used as a counter electrode, the voltage was 1 V, the scan rate was 100 mV / s, and the number of electrochemical polymerization cycles by cyclic voltammetry was 30 to obtain a polymer film. The polymer film was washed in a mixed solvent of dichloromethane and acetonitrile to remove unpolymerized monomers or oligomers on the surface and residual electrolyte, and then placed in a watch glass to dry naturally for use.

[0108] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A carbazole-grafted metal complex monomer, characterized in that: Its structural formula is as follows: in, Each of the alkanes is independently any one of C1 to C10.

2. The method for preparing the carbazole-grafted metal complex monomer according to claim 1, wherein: The following steps are involved: S1, mixing carbazole monomer (1), bromine-substituted alkane, inorganic base A, phase transfer catalyst and organic solvent A and reacting to obtain monomer (2); S2, mixing monomer (2), p-hydroxybenzaldehyde, inorganic base A, phase transfer catalyst and organic solvent A and reacting to obtain monomer (3); S3, mixing monomer (3), 2-acetylpyridine, inorganic base B, amine source and organic solvent B and reacting to obtain monomer (4); S4, mixing the monomer (4), an inorganic salt C and an organic solvent C and reacting them to obtain a carbazole-grafted metal complex monomer (5); the inorganic salt C is one or more of ferrous chloride, ferrous tetrafluoroborate and ferrous acetate; The structural formulas of the carbazole monomer (1), monomer (2), monomer (3), monomer (4) and metal complex monomer (5) are as follows: Carbazole monomer (1), Monomer (2), Monomer (3), Monomer (4), Monomer (5).

3. The preparation method according to claim 2, characterized in that In step S1, the molar ratio of carbazole monomer (1), bromine-substituted alkane, inorganic base A, phase transfer catalyst and organic solvent A is 1-2:2-5:0.3-1:0.5-5:20-40; the reaction temperature is 60-160° C., and the reaction time is 6-72 hours; The bromine-substituted alkane is any alkane of C1 to C10 substituted with bromine; The inorganic base A is one or more of potassium carbonate, sodium carbonate, cesium carbonate, potassium bicarbonate and sodium bicarbonate; The phase transfer catalyst is one or more of 18-crown ether-6, tetrabutylammonium bromide and tetrabutylammonium iodide; The organic solvent A is one or more of ethanol, acetone, dimethylformamide and acetonitrile.

4. The preparation method according to claim 2 or 3, characterized in that In step S2, the molar ratio of monomer (2), p-hydroxybenzaldehyde, inorganic base A, phase transfer catalyst and organic solvent A is 0.5-2:1-5:0.3-1:0.5-5:20-40; the reaction temperature is 60-160° C., and the reaction time is 6-72 h.

5. The preparation method according to claim 4, characterized in that In step S3, the molar ratio of monomer (3), 2-acetylpyridine, inorganic base B, amine source and organic solvent B is 0.5-2:2-5:0.5-1.5:0.5-5:20-40; the reaction temperature is 0-80°C, and the reaction time is 48-96 hours; The inorganic base B is one or more of sodium hydroxide, potassium hydroxide and calcium hydroxide; The amine source is one or more of ammonium chloride, ammonia water and ammonia gas; The organic solvent B is one or more of ethanol, methanol and tetrahydrofuran.

6. The preparation method according to claim 3 or 5, characterized in that In step S4, the molar ratio of the monomer (4), the iron ions in the inorganic salt C, and the organic solvent C is 1-2:0.8-1.5:20-40; The reaction temperature is 0-50° C., and the reaction time is 1-8 hours.

7. The method for forming a polymer film from a carbazole-grafted metal complex monomer according to claim 1, wherein: The following steps are involved: The metal complex monomer grafted with carbazole is added to an electrolyte to obtain a mixed solution, and the mixed solution is subjected to electrochemical cyclic voltammetry to obtain a polymer film; The concentration of the carbazole-grafted metal complex monomer in the mixed solution is 1-10 mmol / L.

8. The method according to claim 7, characterized in that The solvent of the electrolyte is a mixed solvent of acetonitrile and dichloromethane, and the volume ratio of acetonitrile to dichloromethane is 1:1-5; The parameters of the electrochemical cyclic voltammetry are as follows: the electrolyte is one or more of tetrabutylammonium perchlorate, tetrabutylammonium hexafluorophosphate, and lithium perchlorate; the working electrode is any one of ITO glass, FTO glass, ITO-PET substrate, and FTO-PET substrate; the counter electrode is a platinum wire; the scan rate is 100-150 mV / s; the voltage is 0-2 V; and the number of cycles is 20-40.

9. A polymer film prepared by the method according to any one of claims 7 to 8.

10. Use of the polymer film according to claim 9 in displays, smart windows or mobile phone cases.

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