阅读说明：本技术 含亚稳态光酸的智能响应型树枝化共聚物及其制备方法 (Intelligent response type branched copolymer containing metastable state photoacid and preparation method thereof ) 是由 苏新艳 陈会 马琴琴 吕敏 鄂懿 刘坤 李文 张阿方 于 2020-05-21 设计创作，主要内容包括：本发明公开了一种含亚稳态光酸的智能响应型树枝化共聚物及其制备方法,利用树枝化聚合物微环境调控亚稳态光酸异构化,将亚稳态光酸引入到具有温敏特性的烷氧醚树枝化聚合物中,制备一类含亚稳态光酸的智能树枝化共聚物,结合烷氧醚类树形分子优异的水溶性、温敏性和树形结构特点,利用其特殊的拓扑结构提供的微环境的改变实现对体系中各组分间作用力的调节,从而实现对亚稳态光酸异构化的调控。本发明的智能树枝化共聚合物对亚稳态光酸的调控方式具有多重性、环境友好、简单、灵活等特点。因而在生物医药,分子探针,环境监测,光学器件,信息存储以及智能显示等领域中的应用具有指导意义。(The invention discloses an intelligent response type dendronized copolymer containing metastable photoacid and a preparation method thereof, wherein the isomerization of the metastable photoacid is regulated and controlled by utilizing a dendronized polymer microenvironment, the metastable photoacid is introduced into an alkoxy ether dendronized polymer with temperature-sensitive property to prepare an intelligent dendronized copolymer containing the metastable photoacid, and the change of the microenvironment provided by a special topological structure is utilized to realize the regulation of the acting force among components in a system by combining the excellent water solubility, temperature-sensitive property and tree structure characteristics of alkoxy ether tree molecules, so that the isomerization of the metastable photoacid is regulated and controlled. The intelligent dendritic copolymer has the characteristics of multiplicity, environmental friendliness, simplicity, flexibility and the like on a metastable photoacid regulation and control mode. Therefore, the method has guiding significance in the fields of biological medicine, molecular probes, environmental monitoring, optical devices, information storage, intelligent display and the like.)

1. An intelligent response type branched copolymer containing metastable state photoacid, which is characterized in that: the general formula is nEtPG1x-co-PMy, and the structural formula is as follows:

in the structural formula, n is 3 or 6, R is an alkoxy ether dendron with three arms or six arms, the ratio of x to y is 100: 1-10: 1, and x and y are integers of 1-100.

2. The smart responsive dendrimeric copolymer with metastable photoacid generator of claim 1, wherein: r in the structural formula is 3-EtG1 or 6-EtG1 alkoxy ether dendron, and the formula is as follows:

3. the smart responsive dendrimeric copolymer with metastable photoacid generator according to claim 1 or 2, characterized in that: the general formula nEtPG1x-co-PMy x is an integer of 13-38.

4. The smart responsive dendrimeric copolymer with metastable photoacid generator according to claim 1 or 2, characterized in that: a dual response to visible light and temperature can be achieved.

5. A method for preparing the intelligent response type branched copolymer containing the metastable photoacid as claimed in claim 1, wherein the intelligent response type branched copolymer containing the metastable photoacid, nEtPG1x-co-PMy, is prepared by using a dendritic polymer microenvironment to regulate the isomerization of the metastable photoacid, and is characterized in that: the alkoxy ether temperature-sensitive dendritic polymer is utilized to construct a micro-environment with limited molecular level, and the micro-environment regulation is realized through the hydrophilic and hydrophobic property change of the polymer induced by temperature, so that the conformation transformation process in a metastable photoacid water phase is regulated and controlled.

6. The method of claim 5, wherein the method comprises the steps of:

a. dissolving MEH-NH monomer in DMSO, adding triethylamine with the molar weight at least 1.5 times that of the MEH-NH monomer, adding three-arm or six-arm alkoxy ether dendron monomer in nitrogen atmosphere, then adding initiator AIBN, and carrying out polymerization reaction for at least 4 hours at the temperature of not higher than 90 ℃;

b. after the reaction in the step a is finished, adding acetic acid into the product mixed solution at room temperature, and then stirring for at least 1h under a dark condition to obtain a product solution A; then dropwise adding the product solution A into a normal hexane solvent, and precipitating to obtain an orange oily substance;

c. b, collecting the oily matter obtained in the step B, dissolving the oily matter in methanol, dropwise adding a concentrated HCl solution until the concentration of HCl in the mixed solution is not lower than 0.5mol/L, and continuously stirring for at least 1h under a dark condition to obtain a mixed solution B;

d. and c, dropwise adding the mixed solution B obtained in the step c into an n-hexane solvent, precipitating to separate out a polymer, and separating and purifying to obtain the visible light and temperature dual-response intelligent dendritic polymer nEtPG1 x-co-PMy.

7. The method of claim 6, wherein the metastable photoacid-containing smart responsive branched copolymer is a mixture of a solution of a metastable photoacid generator and a water-soluble photoacid generator; in the step a, the molar ratio of the alkoxy ether dendron monomer to the MEH-NH monomer is (9-100): 1.

8. The method of claim 6, wherein the metastable photoacid-containing smart responsive branched copolymer is a mixture of a solution of a metastable photoacid generator and a water-soluble photoacid generator; in the step a, the amount of AIBN used as an initiator for carrying out the polymerization reaction is 0.3-2 wt% of the total mass of the monomers.

9. The method of claim 6, wherein the metastable photoacid-containing smart responsive branched copolymer is a mixture of a solution of a metastable photoacid generator and a water-soluble photoacid generator; in the step a, the polymerization reaction temperature is 50-90 ℃, and the reaction time is 4-15 h.

10. The method of claim 6, wherein the metastable photoacid-containing smart responsive branched copolymer is a mixture of a solution of a metastable photoacid generator and a water-soluble photoacid generator; in the steps b and c, the stirring time of the mixed solution under the dark condition is 1-6 h respectively when adding acid for precipitation.

Technical Field

The invention relates to a branched copolymer and a preparation method thereof, in particular to an intelligent response type branched copolymer and a preparation method thereof, and also relates to a method for regulating and controlling metastable photoacid isomerization, which is applied to the technical field of intelligent response type functional polymers.

Background

Photoacid acts as a bridge to link light and protons, stimulating the release of protons by light. Early reports of photoacid reversibility, known as photoacid generators (PAGs), were not able to recombine protons after they are released under light. With the development of materials, reversible control of proton release and binding by light irradiation is more important, and thus excited photoacid has been widely studied from 1970 s. The excited state photoacid has high acidity when in an excited state under light and can recombine protons to form a low acidity ground state under dark, and is reversible but releases protons at a low concentration. The metastable state photoacid makes up the deficiency of the excited state photoacid. The metastable state photoacid is formed by connecting an Electron Acceptor (EA) and a weak acid nucleophilic part (NuH) through a double bond, the double bond undergoes cis-trans transformation under the irradiation of visible light, the two parts carry out nucleophilic reaction to release protons, the pH value of the solution is changed, and the solution can be recovered after the light irradiation is stopped. The process of releasing protons and combining protons by metastable photoacid is a multi-step reaction, and the half-life of the acid state is mainly determined by the concentration, when the concentration is 10^-5And 10^-3Between M, the half-lives of the different metastable photoacid generators vary from a few seconds to an hour, so that even with moderate intensity illumination, the metastable photoacid generators can be induced to release protons due to their long service life.

The liaoyyi topic group 2011 reports that a metastable Merocyanine (MEH) is transformed into a Spiropyran (SP) configuration under the irradiation of visible light, and the transformation is accompanied by the release of protons and the change of color. The solution characteristic absorption wavelength was changed from 424nm to 300nm, the color was changed from yellow to colorless, the pH was lowered from 5.5 to 3.3, and the half-life was about 70 s. The SP configuration recombines the proton to the MEH configuration after the illumination is stopped. (Shi, Z.; Peng, P.; Strohecker, D.; Liao, Y., Long-live photacid based on a phocochloric reaction [ J ]. J Am Chem Soc 2011 (133) (37), 14699-.

The confined environment places the material in a confined environment, as opposed to a free state, where the material may change its properties significantly after it is confined. By utilizing the characteristic that the performance of the substance is changed in a limited microenvironment, the chemical reaction rate can be improved, highly complex molecules can be synthesized, and the like. The photochromic material may also cause many changes in performance when it is in a confined environment, such as when some professor sammanta puts the spiropyran compound in (Fujita's cage and Mukherjee's cage) confined environment (sammanta, d., et al., Reversible chloromism of spiropyran in the cavity of after-oxidation coordination cage [ J ]. Nat Commun2018,9(1), (641)), when the spiropyran compound MC is isomerized into SP, the unstable intermediate will be stable in the hydrophobic cavity, and at the same time, keep the photo-isomerization characteristic, and when the photo-irradiation is performed, the spiropyran compound MC will be further converted into SP configuration, which is the first study on the performance change of the molecular switch in the confined environment.

In recent years, Zhang Asang and the like report a series of alkoxy ether branched polymers, the polymers combine the characteristics of alkoxy ether and branching structure, show narrow temperature-sensitive phase change temperature and small hysteresis effect, and flexibly regulate and control the LCST of the polymers by regulating the end group structure of branching elements, the generation number of branching elements and the like. (Li, W.; Zhang, A.; Feldman, K., et al., thermo-responsive degraded Polymers [ J ]. Macromolecules 2008,41, 3659-) -3667; Li, W.; Zhang, A.; Schluer, A.D., thermo-responsive condensed Polymers with a tunable solvent solution temperature values [ J ]. Chem Commun (Camb)2008, (43),5523-5.) the Polymers not only have excellent temperature-sensitive characteristics and biocompatibility, but also have a special Dendronized topology and a hydrophobic microenvironment formed after temperature-sensitive phase transition, so that the Polymers have wide application value in the fields of drug control and release, sensors, actuators and the like.

In summary, the control of the chemical properties of molecular switches by constructing a restricted microenvironment is significant in the field of developing novel intelligent optical materials, and is a technical problem to be solved urgently.

Disclosure of Invention

In order to solve the problems of the prior art, the invention aims to overcome the defects of the prior art, provide an intelligent response type dendronized copolymer containing metastable photoacid and a preparation method thereof, and provide a method for regulating and controlling metastable photoacid isomerization by using a dendronized polymer microenvironment. The metastable state photoacid is introduced into the alkoxy ether branched polymer with the temperature-sensitive property to prepare an intelligent dendritic copolymer containing the metastable state photoacid, and the change of a microenvironment provided by a special topological structure is utilized to realize the regulation of the acting force among the components in the system by combining the excellent water solubility, the temperature-sensitive property and the tree structure characteristics of the alkoxy ether tree molecule, so that the regulation of the isomerization of the metastable state photoacid is realized.

In order to achieve the purpose of the invention, the invention adopts the following inventive concept:

the method for regulating the metastable state photoacid isomerization by using the dendronized polymer microenvironment realizes the control of the molecular switch chemical property by constructing the limited microenvironment, and has important significance in the field of developing novel intelligent optical materials. This patent utilizes alkoxy ether temperature sensitive treeing polymer to construct the limited microenvironment of molecular level, and polymer hydrophilicity and hydrophobicity through temperature induction changes, realizes that the apparent change of microenvironment and then regulates and control the conformation transformation process in metastable photo-acid water phase.

The reaction mechanism adopted by the invention is as follows:

the above technical route of the present invention is only exemplified by the polymerization temperature of 70 ℃, and the present invention needs to further determine the range of the polymerization temperature of the present invention.

According to the invention, an alkoxy ether temperature-sensitive dendronized polymer is used for constructing a molecular level limited microenvironment, and the apparent change of the microenvironment is realized through the temperature-induced hydrophilic and hydrophobic property change of the polymer, so that the conformation transformation process in a metastable photoacid water phase is regulated and controlled.

According to the inventive concept, the invention adopts the following technical scheme:

an intelligent response type branched copolymer containing metastable photoacid has a general formula of nEtPG1x-co-PMy, and has a structural formula as follows:

in the structural formula, n is 3 or 6, R is an alkoxy ether dendron with three arms or six arms, the ratio of x to y is 100: 1-10: 1, and x and y are integers of 1-100.

As a preferred technical scheme of the invention, R in the structural formula of the intelligent response type branched copolymer containing the metastable photoacid is 3-EtG1 or 6-EtG1 alkoxy ether branching unit, and the following steps are included:

as a preferable technical scheme of the invention, the x of the intelligent response type branched copolymer containing the metastable photoacid, nEtPG1x-co-PMy, is an integer of 13-38.

As a preferred technical scheme of the invention, the intelligent response type branched copolymer containing the metastable state photoacid can perform double response to visible light and temperature.

The invention relates to a preparation method of an intelligent response type branched copolymer containing metastable photoacid, which utilizes a dendritic polymer microenvironment to regulate and control the isomerization of the metastable photoacid and prepares the intelligent response type branched copolymer containing the metastable photoacid nEtPG1x-co-PMy, and is characterized in that: the alkoxy ether temperature-sensitive dendritic polymer is utilized to construct a micro-environment with limited molecular level, and the micro-environment regulation is realized through the hydrophilic and hydrophobic property change of the polymer induced by temperature, so that the conformation transformation process in a metastable photoacid water phase is regulated and controlled.

As a preferred technical scheme of the invention, the preparation method of the intelligent response type branched copolymer containing the metastable state photoacid comprises the following steps:

a. dissolving MEH-NH monomer in DMSO, adding triethylamine with the molar weight at least 1.5 times that of the MEH-NH monomer, adding three-arm or six-arm alkoxy ether dendron monomer in nitrogen atmosphere, then adding initiator AIBN, and carrying out polymerization reaction for at least 4 hours at the temperature of not higher than 90 ℃;

b. after the reaction in the step a is finished, adding acetic acid into the product mixed solution at room temperature, and then stirring for at least 1h under a dark condition to obtain a product solution A; then dropwise adding the product solution A into a normal hexane solvent, and precipitating to obtain an orange oily substance;

c. b, collecting the oily matter obtained in the step B, dissolving the oily matter in methanol, dropwise adding a concentrated HCl solution until the concentration of HCl in the mixed solution is not lower than 0.5mol/L, and continuously stirring for at least 1h under a dark condition to obtain a mixed solution B;

d. and c, dropwise adding the mixed solution B obtained in the step c into an n-hexane solvent, precipitating to separate out a polymer, and separating and purifying to obtain the visible light and temperature dual-response intelligent dendritic polymer nEtPG1 x-co-PMy.

In a preferred embodiment of the present invention, in the step a, the molar ratio of the alkoxy ether dendron monomer to the MEH-NH monomer is (9-100): 1. Preferably, the molar ratio of the alkoxy ether dendron monomer to the MEH-NH monomer is (9-15): 1.

In the step a, the amount of AIBN used as the initiator for the polymerization reaction is 0.3-2 wt% of the total mass of the monomers.

As a preferable technical scheme of the invention, in the step a, the polymerization reaction temperature is 50-90 ℃, and the reaction time is 4-15 h.

In the steps b and c, the stirring time of the mixed solution under the dark condition is 1-6 h each time the acid is added for precipitation.

The nEtPG1x-co-PMy can effectively regulate and control the isomerization of the metastable photoacid, the MEH chromophore of the metastable photoacid is converted to the SP configuration after the copolymer is irradiated by light, the copolymer is placed in a dark environment, the SP configuration is converted to the MEH configuration, the recovery degree at room temperature is low, and the recovery degree is increased along with the increase of the temperature. The copolymer with different copolymerization ratios and different arm numbers has different regulation and control degrees on the isomerization of the metastable state photoacid. The nEtPG1x-co-PMy has good reversibility and repeatability at different temperatures, and plays a good role in stabilizing metastable photoacid at the same time.

Compared with the prior art, the invention has the following obvious and prominent substantive characteristics and remarkable advantages:

1. the invention designs a class of intelligent dendritic copolymers, and provides a preparation method thereof, which can utilize the dendritic polymer microenvironment to regulate the isomerization of the metastable photoacid, successfully realizes the controllable isomerization of the metastable photoacid regulated by the dendritic polymer microenvironment, and provides a foundation for expanding the application of the metastable photoacid chromophore in the biomedical field;

2. the intelligent dendritic copolymer containing the metastable photoacid is combined with the characteristics of excellent water solubility, temperature sensitivity and tree structure of the alkoxy ether tree molecule, and the change of a microenvironment provided by a special topological structure is utilized to realize the regulation of the acting force among the components in the system, so that the regulation and control of the metastable photoacid isomerization are realized;

3. the method is simple and easy to implement, low in cost and suitable for popularization and application.

Drawings

FIG. 1 shows a three-armed alkoxy ether branched copolymer 3EtPG1 according to one embodiment of the present invention₃₈Of co-PM¹H NMR spectrumFigure (a).

FIG. 2 shows a concentration of 3.6 × 10^-5M example one 3EtPG1₃₈UV spectra of co-PM before and after visible light at 25 ℃ and 45 ℃.

FIG. 3 shows a six-arm alkoxy ether dendronized copolymer 6EtPG1 of example two of the present invention₂₀Of co-PM¹H NMR spectrum.

FIG. 4 shows a concentration of 3.6 × 10^-5M6 EtPG1 of inventive example two₂₀UV spectra of co-PM before and after visible light at 25 ℃ and 45 ℃.

FIG. 5 shows a six-arm alkoxy ether dendronized copolymer 6EtPG1 of example III of the present invention₁₃Of co-PM¹H NMR spectrum.

FIG. 6 shows a concentration of 3.6 × 10^-5M6 EtPG1 of inventive example III₁₃UV spectra of co-PM before and after visible light at 25 ℃ and 45 ℃.

FIG. 7 shows a three-armed alkoxy ether branched copolymer 3EtPG1 according to a first embodiment of the present invention₂₄Of co-PM¹H NMR spectrum.

FIG. 8 shows a concentration of 3.6 × 10^-5M example one 3EtPG1₂₄UV spectra of co-PM before and after visible light at 25 ℃ and 45 ℃.

Detailed Description

Synthesis of three-arm branched alkoxy ether monomers, see literature (Li W, Zhang A, et al. effective synthesis of first-and second-generation, water-soluble branched polymers [ J ]. Macromolecules 2008,41(1),

43-49.) was performed.

Synthesis of six-arm dendronized alkoxy ether monomers was carried out according to the literature (Kim H.J., Zin W.C., Lee M., Anion-Directed Self-Assembly of Coordination Polymer in Tunable Secondary construction [ J ] am. chem. Soc.2004,126, 7009.).

Monomer MEH-NH was synthesized by reference to the literature (Khalil, T.; Alharbi, A.; Baum, C., et al., facility Synthesis and Photoactivity of Merocyanine-Photoacid Polymers [ J ]. macromolRapid Commun2018, 39(15), e 1800319).

The preferred embodiments of the invention are detailed below:

the present invention is further illustrated by the following examples, which are not intended to limit the scope of the present invention in any way. The invention utilizes¹The H NMR method is used for characterizing the structure of a target polymer, and an ultraviolet-visible spectrophotometer is used for characterizing the characteristics of light response and temperature response of the target polymer.

The above-described scheme is further illustrated below with reference to specific embodiments, which are detailed below: