CN110066309B

CN110066309B - Thermo-sensitive-photosensitive dual-stimulus responsive supramolecular organogel

Info

Publication number: CN110066309B
Application number: CN201811104025.0A
Authority: CN
Inventors: 杨海宽; 刘玲玲; 施含旭
Original assignee: North University of China
Current assignee: North University of China
Priority date: 2018-09-07
Filing date: 2018-09-07
Publication date: 2022-01-25
Anticipated expiration: 2038-09-07
Also published as: CN110066309A

Abstract

A thermo-sensitive-photosensitive double-stimulus responsive supramolecular organogel. The invention relates to a gelator containing azobenzene group, the chemical formula of which is C₁₅₆H₂₄₀N₈O₁₈. The supermolecule organogel prepared by the gelator has the temperature-sensitive and photosensitive dual response characteristics, and is particularly characterized in that the supermolecule organogel can generate gel-sol phase transformation after being heated to 80 ℃, and gradually recovers the gel state after standing at room temperature. Under the irradiation of ultraviolet light with the wavelength of 365nm, gel-sol phase transformation occurs, and the gel state can be slowly recovered after the irradiation of visible light with the wavelength of 450 nm. The supermolecule organogel has good temperature-sensitive-photosensitive performance, and can be used as a temperature-sensitive-photosensitive intelligent gel material to be applied to the fields of sensors, intelligent switches, ion detectors and the like.

Description

Thermo-sensitive-photosensitive dual-stimulus responsive supramolecular organogel

Technical Field

The invention belongs to the field of supramolecular material chemistry, and particularly relates to a gelator containing azobenzene groups, a preparation method of the gelator, and a supramolecular organogel with reversible temperature-sensitive and photosensitive dual stimulus response performance, which is obtained from the gelator.

Background

The stimulus-responsive material shows unique intelligent response characteristics under external environment stimulus (such as temperature, light, ultrasound, pH value, mechanical force, chemical substances and the like), such as phase state transition, color change, shape change, fluorescence effect and the like, and is an important research direction in the field of intelligent materials. Among them, the stimulus-responsive gel is sensitive to temperature, light, solvent, etc., and exhibits excellent properties in the aspect of stimulus response, and thus has wide applications in the field of stimulus-responsive materials. The stimulus-responsive gel may be classified into various types such as a photo-responsive gel, a thermo-responsive gel, a pH-responsive gel, a field-responsive gel, and a redox-type gel according to the type of the environmental stimulus. Among them, the photoresponsive gel is reduced in system viscosity and even generates gel-sol phase transition phenomenon under the irradiation of light with specific wavelength, or causes the change of system color, etc. The photoresponse type gel shows good application prospect in the aspects of sensors, intelligent switches, ion detectors and the like as a novel intelligent material.

At present, the preparation method of the photoresponse gel mainly comprises a physical method and a chemical method. The physical method is generally to add a photosensitive substance (such as an aromatic diazo compound or an azide compound, an aromatic nitro compound, chlorophyllin, an organic halogen compound, dichromate, etc.) to an existing gel material. Most of chemical methods are to use photosensitive groups to carry out structural modification on polymers to prepare polymer photosensitive gel factors so as to prepare photoresponse type gel; in addition, researchers have also utilized small organic molecules with photochemical activity to self-assemble directly in a solvent to prepare photoresponsive gels.

However, in the photosensitive polymer gel factor, the gel factor of the homopolymer of the monobasic monomer often has defects or insufficiencies in structure and performance, and the formed polymer gel has poor comprehensive performance and is difficult to meet the application requirements of many fields. Therefore, most of polymer gel factors are multi-monomer copolymers, but the copolymerization method is not easy to control the molecular weight and molecular weight distribution of the obtained product, and the obtained product has large property difference and is not obvious enough in light responsiveness. The organic small molecules with photochemical activity and determined molecular weight are used as the gel factors, the formed photoresponse gel has more stable photoresponse performance, and meanwhile, the driving force during the gel formation is non-covalent bond weak interaction force such as hydrogen bond, van der Waals force and the like, so that the formed gel has thermoreversible performance on the basis of the self photoresponse performance. The stimulus-responsive supramolecular organogel at least has the characteristics of dual response of temperature and illumination. Based on the above, the research and development of the intelligent gel material with multiple environmental response properties is of great significance.

Azobenzene and its derivatives contain photochemically active-N ═ N-groups, and can undergo reversible isomerization and transformation under irradiation of light of a specific wavelength, and the change in the form of the molecule itself causes a change in the supramolecular structure and thus a phase transition of the system. Therefore, the design and synthesis of the novel azobenzene derivative and the application of the azobenzene derivative as a gel factor to prepare the photosensitive supramolecular gel material in the field of intelligent sensing devices are researched, and the azobenzene derivative has very important significance. According to the invention, based on the characteristics of the azobenzene functional group, the azobenzene group is introduced into the gelator, so that the novel gelator containing the azobenzene group is constructed. The supermolecule organogel prepared by the gelator has reversible photosensitive-temperature sensitive dual stimulation response performance.

The related documents are consulted to find that the gelator, the preparation method thereof and the gel formed by the gelator are not reported.

Disclosure of Invention

The invention aims to provide a gelator containing azobenzene groups, which can form stable supramolecular organogel in various organic solvents, and the formed gel has temperature-sensitive and photosensitive dual environmental response characteristics.

Another purpose of the invention is to provide a preparation method of the gelator.

In order to achieve the purpose, the invention takes the chemical formula as C₇₂H₁₁₇N₃O₉The 3, 3 '-bicholesterol succinyl imidazole monoester dipropylamino succinic acid monoamide and 4, 4' -dihydroxyazobenzene are used as raw materials to prepare a novel gel factor, and the chemical formula of the gel factor is C₁₅₆H₂₄₀N₈O₁₈The structural formula is as follows:

the preparation method of the gelator comprises the following steps:

dissolving 3, 3 '-bicholesterol succinimidyl monoester dipropylamino succinic acid monoamide, 4' -dihydroxyazobenzene, 4-dimethylaminopyridine and 1- (3-dimethylaminopropyl) -3-ethyl carbodiimide hydrochloride in chloroform for reaction, and removing the solvent after the reaction to obtain the crude product of the gel factor.

Specifically, in the preparation method, the reaction temperature is 15-38 ℃.

Further, the reaction time is 24-48 hours.

Preferably, in the preparation method, the molar ratio of the 3, 3 '-bicholesterol succinimidyl monoester dipropylamino succinic acid monoamide, 4' -dihydroxyazobenzene, 4-dimethylaminopyridine and 1- (3-dimethylaminopropyl) -3-ethyl carbodiimide hydrochloride is 2-2.1: 1: 0.2-2: 1-3.

Furthermore, the invention provides a simple, but not limiting, purification method for the crude product of gelator, comprising:

recrystallizing the obtained crude product twice by using methanol, and drying in vacuum to obtain powdery yellow solid, namely the gel factor.

The preparation method of the supramolecular organogel comprises the following steps:

weighing a certain amount of gelator, adding a proper amount of organic solvent, adopting a heating mode to completely dissolve the gelator, naturally cooling to room temperature, standing and aging to form the supramolecular organogel.

Specifically, in the preparation method of the supramolecular organogel, the concentration of the gelator is not less than 15 mg/mL.

Further, the aging time should not be less than 0.5 hour.

Preferably, the organic solvent is toluene, o-xylene, m-xylene, p-xylene.

The supramolecular organogel disclosed by the invention has good temperature-sensitive-photosensitive dual stimulus response characteristics. Specifically, the supermolecule organogel can generate gel-sol phase transformation at 80 ℃, and can recover the gel state after standing at room temperature, and the phase transformation of the two states can be repeatedly realized; under 365nm ultraviolet light irradiation, gel-sol phase transformation can occur, and when the gel is irradiated by 450nm visible light irradiation, the gel state can be slowly recovered. The gel-sol phase transformation can be repeatedly carried out, and the gel has good photosensitive property.

The preparation method of the gelator containing the azobenzene group provided by the invention has the advantages of mild reaction conditions, and simple and easy operation of the post-treatment of the crude product. The gelator can form stable supermolecule organogel in various organic solvents, and the formed gel has reversible temperature-sensitive-photosensitive dual stimulation response characteristics. The supermolecule organogel has good reversible temperature-sensitive-photosensitive dual stimulation response characteristics, so that the supermolecule organogel has better application prospect in the research and development of intelligent materials such as photoswitches, sensors and the like.

Drawings

FIG. 1 is a mass spectrum of the gelator prepared in example 1

FIG. 2 is the NMR spectrum of the gelator prepared in example 1

FIG. 3 is a photograph of supramolecular organogels formed in examples 4 to 7

FIG. 4 is a scanning electron micrograph of supramolecular organogel formed in example 4

FIG. 5 is a photo of temperature-sensitive stimuli-responsive state of the supramolecular organogel prepared in example 4

FIG. 6 photo of light-sensitive stimuli-responsive representation of supramolecular organogels prepared in example 9

Detailed Description

The following examples are only preferred embodiments of the present invention and are not intended to limit the present invention in any way. Various modifications and alterations to this invention will become apparent to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Example 1

1.09g of 3, 3 '-bicholesterol succinimidyl dipropylamino succinic acid monoamide, 0.1g of 4, 4' -dihydroxyazobenzene, 0.06g of 4-dimethylaminopyridine and 0.13g of 1- (3-dimethylaminopropyl) -3-ethylcarbodiimide hydrochloride were added to a round-bottomed flask, 80mL of chloroform was added thereto, the reaction was stirred at 25 ℃ for 42 hours, and after the completion of the reaction, the solvent was removed by rotary evaporation to obtain a crude product of the gelator. Recrystallizing the obtained crude product twice by using methanol, and drying in vacuum to obtain powdery yellow solid, namely the gel factor.

Fig. 1 and 2 are a mass spectrum and a nuclear magnetic resonance hydrogen spectrum, respectively, of the gel factor prepared in example 1. The combination of the spectra can well prove that the synthesized product is the gelator. Wherein the characteristic peak of 2537 in figure 1 is the ion proton peak of the target product added with sodium, and no other miscellaneous peak exists in the map. In fig. 2, the solvent peaks are indicated, the main characteristic peaks of which give a clear assignment.

Example 2

1.12g of 3, 3 '-bicholesterol succinimidyl dipropylamino succinic acid monoamide, 0.1g of 4, 4' -dihydroxyazobenzene, 0.02g of 4-dimethylaminopyridine and 0.19g of 1- (3-dimethylaminopropyl) -3-ethylcarbodiimide hydrochloride were added to a round-bottomed flask, 120mL of chloroform was added thereto, the reaction was stirred at 36 ℃ for 26 hours, and after the completion of the reaction, the solvent was removed by rotary evaporation to obtain a crude product of the gelator. The crude product obtained was recrystallized twice from methanol and dried in vacuo to give a yellow powder of gelator.

Example 3

1.14g of 3, 3 '-bicholesterol succinimidyl dipropylamino succinic acid monoamide, 0.1g of 4, 4' -dihydroxyazobenzene, 0.09g of 4-dimethylaminopyridine and 0.21g of 1- (3-dimethylaminopropyl) -3-ethylcarbodiimide hydrochloride were added to a round-bottomed flask, 120mL of chloroform was added thereto, the reaction was stirred at 32 ℃ for 35 hours, and after the completion of the reaction, the solvent was removed by rotary evaporation to obtain a crude product of the gelator. The crude product obtained was recrystallized twice from methanol and dried in vacuo to give a yellow powder of gelator.

Example 4

15mg of the gelator prepared in example 1 was weighed, 1mL of toluene was added, and the solution was heated to completely dissolve the gelator. Naturally cooling at room temperature, standing and aging for 0.5 h to form the supramolecular organogel.

Example 5

17mg of the gelator prepared in example 1 was added to 1mL of o-xylene and heated to completely dissolve the gelator. Naturally cooling at room temperature, standing and aging for 0.5 h to form the supramolecular organogel.

Example 6

20mg of the gelator prepared in example 1 was taken, 1mL of m-xylene was added, and the mixture was heated to completely dissolve the gelator. Naturally cooling at room temperature, standing and aging for 0.5 h to form the supramolecular organogel.

Example 7

22mg of the gelator prepared in example 1 was taken, 1mL of p-xylene was added, and the mixture was heated to completely dissolve the gelator. Naturally cooling at room temperature, standing and aging for 0.5 h to form the supramolecular organogel.

FIGS. 3a-d are photographs of examples 4-7, respectively, illustrating that the gelator can form stable supramolecular organogels in various organic solvents.

FIG. 4 is a scanning electron micrograph of supramolecular organogel formed in example 4. The figure shows that the gel is in a network structure, the gel factor is assembled through hydrogen bonds formed between amide groups and van der waals force between molecules, and finally a three-dimensional network structure is formed, so that solvent small molecules in the system lose fluidity, and the gel is formed.

Example 8

The supramolecular organogel prepared in example 4 was selected, placed in a vacuum oven upside down, heated and the gel state observed. It was found that at 80 ℃ the gel converted to a sol. It is aged by standing again at room temperature, and supramolecular organogel is gradually formed.

Fig. 5 is a photo of temperature sensitive stimuli responsiveness of the supramolecular organogel prepared in example 4. The gel can be converted into sol at 80 ℃, the gel state can be recovered at room temperature, and the gel still keeps the temperature-sensitive characteristic after repeated times.

Example 9

20mg of the gelator prepared in example 1 was weighed and added to a quartz cuvette containing 1mL of toluene to prepare a supramolecular organogel. And (3) irradiating the cuvette under the ultraviolet light with the wavelength of 365nm, and gradually converting the gel into the sol. Then irradiating with visible light with wavelength of 450nm to gradually recover the system to gel state.

FIG. 6 is a photograph showing the gel-sol phase transition of the gel under the alternate stimulation of ultraviolet light and visible light, and the gel (FIG. 6a) and the sol (FIG. 6b) can repeatedly perform phase transition, which shows that the gel has good photosensitive performance.

Claims

1. A gelator with chemical formula of C₁₅₆H₂₄₀N₈O₁₈Having the following structural formula:

2. the process for preparing a gelator according to claim 1, wherein:

dissolving 3, 3 '-bicholesterol succinimidyl monoester dipropylamino succinic acid monoamide, 4' -dihydroxyazobenzene, 4-dimethylaminopyridine and 1- (3-dimethylaminopropyl) -3-ethyl carbodiimide hydrochloride in chloroform according to the molar ratio of 2-2.1: 1: 0.2-2: 1-3 for reaction, recrystallizing a crude product twice by using methanol, and drying in vacuum to obtain the pure gel factor.

3. The method according to claim 2, wherein the reaction temperature is 15 to 38 ℃.

4. The method according to claim 2, wherein the reaction time is 24 to 48 hours.