Diarylethene polymers, methods of making and use thereof

Abstract

The application discloses a diarylethene polymer, and the structure is shown as (formula 1), wherein n is an integer of 2-20, R 1 independently H or F atom, R 2 independently substituted or unsubstituted aryl, and represents cis-trans isomer form. The application further discloses a preparation method of the diarylethene polymer, which comprises the following steps: (1) under the protection of inert gas, carrying out click polymerization of a binary acetylenic compound and a binary mercapto compound in an organic solvent, wherein the polymerization temperature is 20-50 DEG C, the reaction time is 1-4 hours, and the molar ratio of the binary acetylenic compound to the binary mercapto compound is 1:(1-1.1); (2) after the reaction is completed, dissolving the product in an organic solvent, then adding the product into n-hexane to carry out precipitation, collecting the precipitate, and drying to constant weight, so as to obtain the diarylethene polymer. The preparation method is high in efficiency, mild in condition, simple and easy to implement, and good in atom economy, and the obtained diarylethene polymer can be used in anti-fake and copy materials.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of photochromic polymers, in particular to a diarylethene polymer, a preparation method and application thereof. BACKGROUND

[0002] Controlling the physical properties of materials by external stimuli is crucial for the development of molecular devices. Photochromic compounds are the most popular class of molecular switches, which can achieve rapid and local control of molecules using light and do not cause physical and chemical reactions in the surrounding sensitive environment. Among them, diarylethene (DTE) molecules exhibit excellent photochromic properties, outstanding fatigue resistance and good thermal stability in solution, solid and crystal, which are favored by scientists. During the dynamic transformation process, these molecules change the electronic properties and topological structure, and have very attractive application prospects in the fields of waveguide, information storage and optoelectronics. In order to develop these small molecular compounds into practical photoresponsive functional materials, they are usually doped with polymers to make the material have good processing performance. However, the doped material still has some problems such as uneven doping, small molecule aggregation and precipitation. Therefore, it is undoubtedly a better choice to introduce DTE units into the polymer backbone by covalent bond.

[0003] Most of the synthesis methods of DTE-containing polymers reported at present have problems such as complicated synthesis, harsh conditions, etc., and the stability of the obtained products is poor. Therefore, it is of important scientific significance and application value to develop a simple and efficient polymerization method to introduce DTE into polymers to prepare diarylethene polymers with excellent photochromic properties. SUMMARY

[0004] In order to overcome the shortcomings and deficiencies of the prior art, the present application provides a diarylethene polymer, the structure of which is shown as formula (1):

[0005]

[0006] In formula (1), n is an integer of 2-20, R 1 independently H or F atom, R 2 independently substituted or unsubstituted aryl, represents cis-trans isomer form.

[0007] Preferably, R 2 is any one of the following chemical structural formulas 1-6:

[0008]

[0009] Wherein, * represents the substitution position.

[0010] Specifically, the diarylethene polymer is one of the following specific polymers:

[0011]

[0012] wherein n is an integer of 2-20, represents cis-trans isomer forms.

[0013] Another object of the present application is to provide a preparation method of a diarylethene polymer, which is simple and efficient, has mild conditions, and can synthesize a polymer with high molecular weight. The method comprises the following steps:

[0014] (1) under the protection of inert gas, click polymerization of a binary alkyne compound and a binary mercapto compound in an organic solvent, the polymerization reaction temperature is 20-50℃, and the reaction time is 1-4 hours; the molar ratio of the binary alkyne compound to the binary mercapto compound is 1:(1-1.1);

[0015] (2) after the reaction is completed, the product is dissolved in an organic solvent, and then precipitated by adding into n-hexane, the precipitate is collected and dried to constant weight to obtain a diarylethene polymer (formula 1);

[0016]

[0017] The structure general formula of the binary alkyne compound is shown as (formula 2),

[0018]

[0019] The binary mercapto compound is shown as (formula 3),

[0020] HS-R 2 -SH (formula 3)

[0021] In (formula 1), n is an integer of 2-20, and R 1 is independently H or F atom, and R 2 is independently substituted or unsubstituted aryl, represents cis-trans isomer forms.

[0022] Specifically, R 2 is any one of the following chemical structural formulas 1-6:

[0023]

[0024] Preferably, the organic solvent is at least one of tetrahydrofuran, toluene, dimethyl sulfoxide and N,N-dimethylformamide.

[0025] Preferably, the concentration of the diacetylene compound in the organic solvent is 0.025-0.1 mol / L.

[0026] Another object of the present application is to provide the use of the above-mentioned diarylethene polymer, particularly in anti-counterfeiting and copy materials.

[0027] Compared with the prior art, the present application has the following advantages and beneficial effects:

[0028] 1. The diarylethene polymer disclosed in the present application has good film-forming property and is easy to process, and can be directly made into a film for application.

[0029] 2. The diarylethene polymer disclosed in the present application has excellent photochromic properties, and can quickly realize the closed loop / open loop response under the alternating irradiation of ultraviolet light / visible light; and has excellent fatigue resistance.

[0030] 3. The preparation method disclosed in the present application has the advantages of mild conditions, simple process and high polymerization efficiency, and high yield and high molecular weight polymer can be obtained in 2 hours at 30℃.

[0031] 4. The polymerization process of the present application does not generate by-products, which meets the atomic economy.

[0032] 5. The diarylethene polymer obtained in the present application can be applied to anti-counterfeiting and copy materials, further expanding the application field and range of the material. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 is the nuclear magnetic resonance hydrogen spectrum of the diarylethene polymer P1 and its corresponding monomer in CDCl3.

[0034] Figure 2 is the ultraviolet absorption spectrum of the diarylethene polymer P1 solution after ultraviolet light irradiation.

[0035] Figure 3 is the change diagram of the absorption value at 635 nm of the diarylethene polymer P1 under the alternating irradiation of ultraviolet light and visible light.

[0036] Figure 4 is the anti-counterfeiting material model of the diarylethene polymer P1.

[0037] Figure 5 is the copy material model of the diarylethene polymer P1. DETAILED DESCRIPTION

[0038] The present application will be further described in detail below in combination with examples, but the embodiments of the present application are not limited thereto.

[0039] Example 1

[0040] Diarylethylene polymer P1 was prepared by click polymerization of M1 and M2 under catalytic-free conditions.

[0041]

[0042] Monomer M1 was synthesized according to the synthetic methods described in the published literature (Macromolecules, 2012, 45, 7692; Chem. An Asian J., 2013, 9, 104; Polym. Chem., 2014, 5, 2301); M2 was purchased from Energie.

[0043] 41.6 mg (0.1 mmol) of monomer M1 and 25.0 mg (0.1 mmol) of monomer M2 were added to a 10 mL polymerization tube. The tube was evacuated three times with nitrogen. 2 mL of ultra-dry tetrahydrofuran (THF) was injected using a syringe. After the monomers were completely dissolved, the tube was placed in an oil bath maintained at 30 °C and reacted for 2 hours. After the reaction was complete, 1 mL of THF was added, and the resulting polymer solution was added dropwise to 60 mL of vigorously stirred n-hexane. The mixture was allowed to stand, filtered, and dried to obtain the diarylethene polymer P1. Analysis showed that the yield of product P1 was 71%, the weight-average molecular weight was 7100, and the molecular weight distribution was 1.49 (molecular weight and molecular weight distribution were determined using an ultra-high performance polymer chromatography (GPC) system equipped with a diode array detector. THF was used as the mobile phase at a flow rate of 0.5 mL / min, and linearly distributed polystyrene (PS) was used as a standard for correction).

[0044] The 1H NMR spectra of diarylethene polymer P1 and its corresponding monomers (* represents solvent peaks) are shown below. Figure 1 .from Figure 1 C shows the disappearance of the acetylene hydrogen peak at chemical shift 3.35 ppm and the mercapto peak at chemical shift 3.45 ppm, and the appearance of hydrogen peaks of different cis-trans isomers of olefins at chemical shifts of 6.33-7.08 ppm; the above results indicate that the monomer reacted completely to obtain the diarylene ethylene polymer P1.

[0045] Example 2

[0046] Photochromic properties of diarylethylene polymer P1.

[0047] The open-ring diarylethylene polymer (P1-O) transforms into the closed-ring diarylethylene polymer (P1-C) under ultraviolet light irradiation. For example... Figure 2The polymer P1-O has little absorption in the visible region above 400 nm, and its THF solution is almost colorless. After irradiation of UV light, the diarylethene moiety undergoes a ring-closing reaction, and the polymer changes from the open-ring state to the closed-ring state, and an obvious absorption appears at about 630 nm, and its THF solution turns into dark green. When irradiated with visible light, the closed-ring state of the diarylethene will undergo ring-opening reaction to become open-ring state, and the color of the polymer solution will also return to the original color. In the state of polymer P1 thin film, similar to the photochromic phenomenon in solution can also be observed.

[0048] Example 3

[0049] Fatigue resistance of the photochromic diarylethene polymer P1.

[0050] In view of the good film-forming properties of the polymer, a thin film of the polymer P1 was prepared by film casting, and the fatigue resistance of the photochromic property was explored. As shown in Figure 3 The polymer thin film was irradiated with 365 nm UV light for 1 minute, and then irradiated with visible light greater than 550 nm for 15 minutes, and the change in the absorption value at 635 nm was monitored. The results show that after 10 cycles of repeated irradiation, the absorption value at 635 nm has not decreased significantly, indicating that the polymer P1 has very good fatigue resistance.

[0051] Example 4

[0052] Anti-counterfeiting material model of the diarylethene polymer P1.

[0053] Figure 4 The THF solution of the diarylethene polymer P1 was written on a silica gel plate with a capillary to form the word "SCUT". When the concentration is very low, the silica gel plate is basically not visible any word; after irradiation of 365 nm UV light, the open-ring state of the diarylethene is converted to the closed-ring state, and the color of the word becomes light green, and the information is revealed. When irradiated with visible light greater than 550 nm for a period of time, the diarylethene moiety is converted from the closed-ring state to the open-ring state, and the color of the word will disappear. It can be seen that the color of the word can be reversibly read and erased by UV / visible light irradiation, and therefore the diarylethene polymer P1 can be well applied to anti-counterfeiting labels.

[0054] Example 5

[0055] Copy material model of the diarylethene polymer P1.

[0056] As shown in Figure 5As shown, first, the THF solution of polymer P1 was sprayed on the filter paper, no color change was observed, and the ink green fluorescence was emitted under the UV lamp; then, the "cat" pattern was appeared under the sunlight after using the mold and UV irradiation for 5 min; then, the pattern information was erased by using the visible light; again, the "dog" pattern was obtained by using the mold and UV irradiation for 5 min; and so on, the erasable writing operation was realized. This concept of erasable pattern demonstrates the potential application of diarylethene polymer as a medium in the field of duplicating printing and optical storage.

[0057] Example 6

[0058] The click polymerization reaction of M3 and M2 without catalysis was used to prepare the diarylethene polymer P2.

[0059] In which, the monomer M3 was synthesized according to the synthesis method in the published literature (Macromolecules, 2012, 45, 7692; Chem. An Asian J., 2013, 9, 104; Polym. Chem., 2014, 5, 2301); M2 was purchased from the company of Sigma-Aldrich.

[0060]

[0061] In a 10 mL polymerization tube, 30.8 mg (0.1 mmol) of monomer M3, 25.0 mg (0.1 mmol) of monomer M2 were added, vacuumed and replaced with nitrogen for three times, 2 mL of super dry THF was injected by using a syringe, and then the oil bath was put into the constant 30℃, and the reaction was carried out for 2 hours. After the reaction was completed, 1 mL of THF was added, and the obtained polymer solution was added dropwise into 60 mL of vigorously stirred n-hexane, and then it was placed, filtered and dried to obtain the diarylethene polymer P2. The yield of the product P2 was 65%, the weight average molecular weight was 6900, and the molecular weight distribution was 2.02 (the molecular weight and the molecular weight distribution were determined by GPC equipped with a diode array detector. THF was used as the mobile phase, the flow rate was 0.5 mL / min, and the linear monodisperse PS was used as the standard for correction).

[0062] Example 7

[0063] The click polymerization reaction of M1 and M4 without catalysis was used to prepare the diarylethene polymer P3.

[0064] In which, the monomer M1 was synthesized according to the synthesis method in the published literature (Macromolecules, 2012, 45, 7692; Chem. An Asian J., 2013, 9, 104; Polym. Chem., 2014, 5, 2301); M4 was purchased from the company of TCI.

[0065]

[0066] In a 10 mL polymerization tube, 41.6 mg (0.1 mmol) of monomer M1, 14.2 mg (0.1 mmol) of monomer M4 were added, vacuumed and refilled with nitrogen for three times, 2 mL of super dry THF was injected by a syringe, and then the mixture was put into an oil bath which had been kept at 30 °C for 2 hours after the monomers were completely dissolved. After the reaction was completed, 1 mL of THF was added, and the obtained polymer solution was added dropwise into 60 mL of vigorously stirred n-hexane. After standing, filtration and drying, the diarylethene polymer P3 was obtained. The yield of the product P3 was 78%, and the weight average molecular weight was 7500 with a molecular weight distribution of 1.62 (The molecular weight and the molecular weight distribution were determined by GPC equipped with a diode array detector. THF was used as the mobile phase with a flow rate of 0.5 mL / min, and linear monodispersed PS was used as the standard for calibration).

[0067] Example 8

[0068] The click polymerization reaction of M1 and M5 was carried out without catalysis to prepare the diarylethene polymer P4.

[0069] Among them, the monomer M1 was synthesized according to the synthesis method in the published literature (Macromolecules, 2012, 45, 7692; Chem. An Asian J., 2013, 9, 104; Polym. Chem., 2014, 5, 2301); and M5 was purchased from TCI company.

[0070]

[0071] In a 10 mL polymerization tube, 41.6 mg (0.1 mmol) of monomer M1, 14.2 mg (0.1 mmol) of monomer M5 were added, vacuumed and refilled with nitrogen for three times, 2 mL of super dry THF was injected by a syringe, and then the mixture was put into an oil bath which had been kept at 30 °C for 2 hours after the monomers were completely dissolved. After the reaction was completed, 1 mL of THF was added, and the obtained polymer solution was added dropwise into 60 mL of vigorously stirred n-hexane. After standing, filtration and drying, the diarylethene polymer P3 was obtained. The yield of the product P3 was 78%, and the weight average molecular weight was 7500 with a molecular weight distribution of 1.62 (The molecular weight and the molecular weight distribution were determined by GPC equipped with a diode array detector. THF was used as the mobile phase with a flow rate of 0.5 mL / min, and linear monodispersed PS was used as the standard for calibration).

[0072] The above embodiments are the preferred embodiments of the present application, but the embodiments of the present application are not limited by the above embodiments, and any changes, modifications, substitutions, combinations, simplifications, etc. made without departing from the spirit and principles of the present application shall be equivalent replacement manners and shall be included in the protection scope of the present application.

Claims

1. A diarylethylene polymer, characterized in that, The structure is shown in (Equation 1): In equation (1), n ​​is an integer from 2 to 20, and R 1 Independently, it consists of H or F atoms, R 2 Independent aryl groups, whether substituted or unsubstituted. Indicates the cis-trans isomer form.

2. The diarylethylene polymer according to claim 1, characterized in that, The R 2 It is any one of the following chemical structural formulas 1 to 6: In this context, * indicates a replacement position.

3. The diarylethylene polymer according to claim 1, characterized in that, It is one of the following specific polymers: Where n is an integer from 2 to 20, Indicates the cis-trans isomer form.

4. A method for preparing the diarylethylene polymer according to any one of claims 1 to 3, characterized in that, Includes the following steps: (1) Under inert gas protection, the dialkynyl compound and the dithiol compound are subjected to click polymerization in an organic solvent. The polymerization temperature is 20-50°C and the reaction time is 1-4 hours. The molar ratio of the dialkynyl compound to the dithiol compound is 1:(1-1.1). (2) After the reaction is complete, the product is dissolved in an organic solvent and then added to n-hexane for precipitation. The precipitate is collected and dried to constant weight to obtain diarylethene polymer (Formula 1). The general structural formula of the aforementioned diacetyl group compound is shown in Formula 2. The aforementioned dithiol compound is shown in (Formula 3). HS-R 2 -SH (Formula 3) In equation (1), n ​​is an integer from 2 to 20, and R in equations (1) to (3) 1 Independently, it consists of H or F atoms, R 2 Independent aryl groups, whether substituted or unsubstituted. Indicates the cis-trans isomer form.

5. The method for preparing the diarylethylene polymer according to claim 4, characterized in that, The R 2 It is any one of the following chemical structural formulas 1 to 6:

6. The method for preparing the diarylethylene polymer according to claim 4, characterized in that, The organic solvent is at least one of tetrahydrofuran, toluene, dimethyl sulfoxide, and N,N-dimethylformamide.

7. The method for preparing the diarylethylene polymer according to claim 4, characterized in that, The concentration of the dialkynyl compound in the organic solvent is 0.025–0.1 mol / L.

8. The use of the diarylethylene polymer according to any one of claims 1 to 3 in anti-counterfeiting and copying materials.

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