A photochromic chiral supramolecular hydrogel and preparation method thereof
The formation of hand -to -hydraulic hydrogel is formed through the self -assembling self -assembly of the lino -pyrine glutamic acid molecule, which solves the challenge of stable and organic free radicals, and achieves excellent optical discoloration properties and manual expression. It is suitable for smart molecular switches, data storage, and data storage and Light electrical components and other fields.
Patent Information
- Application Number
- CN202310185183.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-03-01
- Publication Date
- 2025-01-24
- Estimated Expiration
- 2043-03-01
AI Technical Summary
Building stable organic radical species has been a challenge in developing organic radical materials, and the application potential of photochromic hydrogel materials in the fields of smart wearable display and biosensing has been underutilized.
By the formation of hydrogels for formation of hand -pyrine glutamic acid molecules self -assembly, using its light -to -blue color deformation properties quickly becomes blue -purple under ultraviolet light or solar light, realizing the stable isolation and handling of free radicals Express.
Realized hand -hydrogel materials with excellent optical discoloration properties, which can quickly change color and recover under ultraviolet light. It has a long discoloration behavior and shows hands -based optical activity. It is suitable for smart molecular switches, data Storage and optoelectronic devices and other fields.
Smart Images
Figure FHA0000008636010000011 
Figure GHA0000008636020000021 
Figure GHA0000008636020000031
Abstract
Description
Technical Field
[0001] The invention relates to a photochromic chiral supramolecular hydrogel and a preparation method thereof, and belongs to the field of photochromic hydrogel materials. Background Art
[0002] Photochromism refers to the phenomenon that compounds undergo photoisomerization under light excitation to form isomers with new chemical structures, accompanied by changes in the absorption spectrum. Generally, the photoisomerization process is reversible. Photochromism is an important optical phenomenon and has a wide range of practical applications in the fields of smart molecular switches, data storage, optoelectronic devices, etc. The mechanism of organic photochromism can be roughly divided into heterolytic bond cleavage, homolytic bond cleavage, cis-trans isomerization, pericyclic reaction, redox, and dimerization. Among them, photochromic molecules that can undergo homolytic bond cleavage to form organic free radicals through light irradiation are an important class of organic functional molecules and have received widespread attention from researchers.
[0003] Organic free radicals are a class of chemical species containing unpaired electrons. The unique open shell structure gives free radicals rich physical and chemical properties, and they have shown broad application value in many fields such as optoelectronic materials, magnetic materials, biomedical materials, energy storage, organic catalysis, polymer science, etc. Due to their contactless spatiotemporal controllability, photoinduced free radical materials have been used in catalysis, polymerization, photoswitches, photodynamic therapy and other fields. However, the construction of stable organic free radical species has always been a challenge in the development of organic free radical materials. The stabilization of highly active free radical species can be achieved by extending the conjugated group to increase spin delocalization, modifying the steric group, introducing heteroatoms, and host-guest interactions, thereby obtaining persistent organic free radicals. In addition, supramolecular assembly has also been proven to be a method for constructing stable organic free radicals. Through the orderly arrangement and aggregation of molecules, the formed free radical active centers can be isolated from the oxygen in the environment to avoid quenching by triplet oxygen. By covalently linking the chiral assembly unit with the free radical active unit, the chiral expression of the free radical can be realized while realizing supramolecular assembly, and the free radical material with chiral optical activity can be prepared, which has application prospects in chiral catalysis, information storage, spin materials, etc. Due to its excellent biocompatibility, the photochromic hydrogel material shows unique application potential in the fields of smart wearable display and biosensor. Summary of the invention
[0004] The purpose of the present invention is to provide a photochromic supramolecular hydrogel material which can be prepared by supramolecular assembly and has excellent photochromic properties.
[0005] The present invention first provides a biquinoline glutamic acid molecule, the structural formula of which is shown in Formula I, that is, a pair of chiral amphiphilic molecules are obtained by covalently connecting a 2,2'-biquinoline-4,4'-dicarboxylic acid molecule and an L-glutamic acid molecule or a D-glutamic acid molecule through an amide bond;
[0006]
[0007] The present invention also provides a method for preparing the biquinoline glutamic acid shown in formula I, comprising the following steps:
[0008] S1. In the presence of triethylamine, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and 1-hydroxybenzotriazole, 2,2'-biquinoline-4,4'-dicarboxylic acid and diethyl glutamate hydrochloride are reacted to obtain diethyl biquinoline glutamate;
[0009] S2. In the presence of lithium hydroxide, the biquinoline glutamic acid diethyl ester is subjected to a hydrolysis reaction to obtain the biquinoline glutamic acid represented by the formula I;
[0010] The solvent used in the hydrolysis reaction is a mixture of tetrahydrofuran and water, and the volume ratio can be 1:1.
[0011] Based on the biquinoline glutamic acid, the present invention provides a photochromic hydrogel;
[0012] The biquinoline glutamic acid is added into water, heated until dissolved, and cooled to room temperature to obtain the product.
[0013] The mass volume ratio of the biquinoline glutamic acid to the water is 1 mg / ml to 3 mg / mL, which will affect the formation of the hydrogel and further affect the color change properties. If the concentration is too low, a firm hydrogel cannot be formed and the color change effect is not obvious; if the concentration is too high, the formed hydrogel is unstable.
[0014] At room temperature, the photochromic hydrogel is light yellow, and when irradiated with ultraviolet light or sunlight, it quickly turns blue-purple, wherein the irradiation time can be 3 to 5 minutes; the ultraviolet spectrum observes the appearance of a new absorption peak at 400 to 800 nm, and the electron paramagnetic resonance spectrum observes an obvious free radical signal; and the blue-purple hydrogel can be restored to a light yellow transparent hydrogel after being placed in the dark overnight. The above color change process can be repeated.
[0015] The invention prepares chiral supramolecular hydrogel with photochromic property by assembling organic small molecules.
[0016] The photochromic hydrogel of the present invention can be used to prepare intelligent molecular switches, data storage, optoelectronic devices, etc.
[0017] The present invention realizes a supramolecular hydrogel material with excellent photochromic properties by a biquinoline glutamic acid self-assembly method. Scanning electron microscope photos show that biquinoline glutamic acid molecules in the hydrogel self-assemble to form nanofibers with an interpenetrating network structure, which is conducive to isolating external oxygen and stabilizing free radicals, thereby showing long-term color change behavior. Moreover, circular dichroism tests show that the supramolecular free radicals generated by light have chiral characteristics. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 This is an electron scanning micrograph of nanofibers with an interpenetrating network structure formed by self-assembly of biquinoline glutamate molecules in water.
[0019] Figure 2 This is the UV-visible absorption spectrum of the biquinoline glutamic acid supramolecular hydrogel changing with UV irradiation time.
[0020] Figure 3 These are photos of biquinoline glutamate supramolecular hydrogel before and after UV irradiation.
[0021] Figure 4 This is the electron paramagnetic resonance spectrum of the biquinoline glutamic acid supramolecular hydrogel before and after ultraviolet light irradiation.
[0022] Figure 5 Circular dichroism spectra of biquinoline glutamic acid supramolecular hydrogel before and after UV irradiation.
[0023] Figure 6 These are photos of the solid powder sample of biquinoline glutamic acid molecule before and after ultraviolet light irradiation.
[0024] Figure 7 This is the electron paramagnetic resonance spectrum of the biquinoline glutamic acid solid powder sample before and after ultraviolet light irradiation. DETAILED DESCRIPTION
[0025] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.
[0026] Unless otherwise specified, the materials and reagents used in the following examples can be obtained from commercial sources.
[0027] Example 1. Preparation of biquinoline glutamic acid molecules (Formula I) and supramolecular hydrogels with photochromic properties
[0028] The synthetic route of biquinoline glutamic acid is as follows:
[0029]
[0030] 1) Dissolve glutamic acid diethyl ester hydrochloride (1.46 g, 6.1 mmol) in 100 mL of N,N-dimethylformamide in a 250 mL round-bottom flask. Add triethylamine (0.64 g, 6.38 mmol) and stir for 1 hour. Add 2,2'-biquinoline-4,4'-dicarboxylic acid (1 g, 2.9 mmol), 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride (1.22 g, 6.2 mmol), and 1-hydroxybenzotriazole (0.86 g, 6.2 mmol) to the reaction solution and continue stirring. React at room temperature for 12 hours. Evaporate the reaction solution to dryness, add dichloromethane, and wash it three times with NaHCO3 aqueous solution. Separate by column chromatography (dichloromethane and methanol) to obtain biquinoline glutamic acid diethyl ester (1.8 g, 2.52 mmol, yield 86.8%).
[0031] In a 250mL single-mouth bottle, dissolve diethyl biquinoline glutamate (0.9g, 1.25mmol) and lithium hydroxide (0.658g, 15.7mmol) in a mixed solvent of 50mL tetrahydrofuran and 50mL deionized water, and stir at room temperature for 12 hours. Adjust the pH of the reaction solution to 3 with hydrochloric acid, remove part of the tetrahydrofuran by vacuum filtration, and precipitate the crude product. Dissolve the crude product in 50mL hot methanol, add 300ml water while hot to precipitate the product, and filter and dry to obtain the target product biquinoline glutamate (0.65g, 85.5%)
[0032] The structural verification data of the target product are as follows:
[0033] 1 H NMR (400MHz, DMSO-d6, 298K, δ, ppm): 13.50-11.69 (m, 2H), 9.23 (s, 2H), 8.81 (s, 2H), 8.28 (t, J = 7.4Hz, 4H), 7.91 (t, J = 7.6H z,2H),7.75(t,J=7.8Hz,2H),4.62–4.51(m,2H),2.44(d,J=7.6Hz,4H),2.14(d,J=7.7Hz,2H),1.98(dd,J=14.1,8.3Hz,2H).
[0034] 13 C NMR(100MHz,DMSO-d6,298K,δ,ppm):174.18,173.50,167.56,154.79,147.99, 144.07,131.10,130.23,128.70,126.08,125.15,116.63,52.49,30.84,26.37.
[0035] HR-MALDI-TOF MS:m / z calcd.for C 30 H 27 N4O 10 :602.16489.Found:[M+H] + ,603.17217.
[0036] 2) Weigh 3 mg of biquinoline glutamic acid molecules into a 4 mL sample bottle, add 1 mL of deionized water, heat until completely dissolved, and let stand to cool to room temperature to form a colorless or light yellow transparent gel.
[0037] The hydrogel samples were tested, e.g. Figure 2 As shown (the red curve is the UV-visible absorption spectrum of the hydrogel before irradiation, and the blue curve is the UV-visible absorption spectrum after 5 minutes of irradiation), the UV-visible absorption spectrum shows that the hydrogel has two main absorption peaks (260nm and 340nm) in the range of 200-450nm before UV irradiation (red line).
[0038] By observing the xerogel sample under a scanning electron microscope, we can see that the nanofibers formed an interpenetrating network structure, such as Figure 1 shown.
[0039] The hydrogel was irradiated with UV light for 5 minutes, and the color of the gel was observed to change from light yellow to blue purple. Figure 3 shown.
[0040] Figure 2 The mid-UV-visible absorption spectrum shows that the hydrogel (blue line) after UV irradiation has a new broad absorption peak in the range of 450-800 nm. The electron paramagnetic resonance spectrum shows that the photochromism of the hydrogel is due to the light-induced generation of organic free radicals, which have different absorption spectra, such as Figure 4 shown.
[0041] like Figure 5 As shown, the photochromic organic free radicals have chiral optical activity and exhibit characteristic absorption of single chiral circularly polarized light.
[0042] Example 2: Photochromic properties of biquinoline glutamic acid molecule solid powder
[0043] The solid powder of biquinoline glutamic acid molecule was irradiated with ultraviolet light for 5 minutes, and it was observed that the solid powder changed from bright yellow to orange yellow, and the color change was not obvious, such as Figure 6 shown.
[0044] At the same time, the electron paramagnetic resonance spectrum observed that after 5 minutes of ultraviolet light irradiation, the solid powder sample showed a weak paramagnetic signal, such as Figure 7As shown. This shows that in the solid powder state, the free radicals generated by light are unstable and can be easily quenched by oxygen in the air.
Claims
1. Biquinoline glutamic acid represented by formula Ⅰ; 2. The method for preparing the biquinoline glutamic acid represented by formula I according to claim 1, comprising the following steps: S1. In the presence of triethylamine, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and 1-hydroxybenzotriazole, 2,2'-biquinoline-4,4'-dicarboxylic acid and diethyl glutamate hydrochloride are reacted to obtain diethyl biquinoline glutamate; S2. In the presence of lithium hydroxide, the biquinoline glutamic acid diethyl ester is subjected to a hydrolysis reaction to obtain the biquinoline glutamic acid represented by the formula I; The solvent used in the hydrolysis reaction is a mixture of tetrahydrofuran and water.
3. Use of the biquinoline glutamic acid according to claim 1 in the preparation of photochromic hydrogel.
4. The use according to claim 3, characterized in that: The biquinoline glutamic acid is dissolved in water to obtain the photochromic hydrogel.
5. The use according to claim 3 or 4, characterized in that: The mass volume ratio of the biquinoline glutamic acid to the water is 1 mg / ml to 3 mg / mL.
6. The use according to claim 5, characterized in that: The photochromic hydrogel changes color under the irradiation of ultraviolet light or sunlight, and the color is restored after being protected from light; The irradiation time is 3 min to 5 min.
7. A photochromic hydrogel obtained by dissolving the biquinoline glutamic acid as claimed in claim 1 in water.
8. The photochromic hydrogel according to claim 7, characterized in that: The mass volume ratio of the biquinoline glutamic acid to the water is 1 mg / ml to 3 mg / mL.
9. The method for preparing the photochromic hydrogel according to claim 7 or 8, comprising the following steps: adding the biquinoline glutamic acid into water, heating until dissolved, and cooling to room temperature to obtain the hydrogel.
10. Use of the photochromic hydrogel according to claim 7 or 8 in the preparation of intelligent molecular switches, data storage, optoelectronic devices, color-changing coatings, and anti-ultraviolet skin care products.