Photochemical deoxygenated micelles, and preparation method and application thereof

Abstract

The application relates to a photochemical deoxygenation micelle as well as a preparation method and application thereof, and belongs to the technical field of nonlinear optical materials. The application prepares a photochemical deoxygenation micelle for protecting a photosensitizer excited triplet state, which comprises a surfactant, a luminescent compound and a solvent; the hydrophobic end of the surfactant in the photochemical deoxygenation micelle coats the luminescent compound; and the luminescent compound is a photosensitizer or a mixture of a photosensitizer and a quencher. The photochemical deoxygenation micelle prepared by the application can realize the application of an up-conversion system in an aerobic environment, and expand the application of TTA-UC in the fields of biological imaging, solar energy utilization and the like.

Description

Technical Field

[0001] This invention relates to the field of nonlinear optical materials technology, and in particular to a photochemical deoxygenating micelle, its preparation method, and its application. Background Technology

[0002] Micelles are aggregates (or supramolecular assemblies) formed by surfactant molecules dispersed in a liquid. Surfactants dissolve in water, and at low concentrations, they exist as monomolecules or are adsorbed onto the surface of the solution, reducing surface tension. When the surfactant concentration increases to the point where the solution surface is saturated and can no longer adsorb, surfactant molecules begin to migrate into the interior of the solution. Because the hydrophobic portion of surfactant molecules has a weak affinity for water, while the hydrophilic portion has a strong attraction between itself, when a certain concentration is reached, the hydrophobic portions of many surfactant molecules (typically 50–150) attract each other and associate together, forming an aggregate, which is a micelle. The core of a micelle is a hydrophobic environment that can encapsulate some lipid-soluble molecules.

[0003] Therefore, micelles can be used to dissolve lipid-soluble molecules in aqueous solutions. Triplete-triplet annihilation photon upconversion (TTA-UC) is a pathway that enables photon upconversion under weak light excitation and has shown potential applications in areas such as bioimaging, sunlight utilization, and luminescent probes. The TTA-UC system mainly consists of a photosensitizer (energy donor), an annihilator (energy acceptor), and a medium dispersing both. Most reported photosensitizers and annihilators are currently non-water-soluble, and even in cases where TTA-UC in aqueous solutions has been reported, the upconversion efficiency is very low. These practical problems limit the application of TTA-UC in aquatic environments. TTA-UC involves energy transfer between excited triplet states of the photosensitizer and annihilator, as well as between excited triplet states of two annihilator molecules. Therefore, the TTA-UC process is highly sensitive to oxygen and must be carried out under strictly anaerobic conditions.

[0004] When a molecule in its ground state absorbs ultraviolet-visible light, if the electrons of the excited molecule undergo spin inversion in the excited state, an intersystem crossing occurs when the lower vibrational energy level of its singlet state overlaps with the higher energy level of the excited triplet state. This leads to the excited triplet state, which, after vibrational relaxation, reaches its lowest vibrational energy level and then emits a photon, transitioning to any vibrational energy level of the ground state. This emitted photon is called phosphorescence. Since phosphorescence has a lifetime on the order of microseconds, and molecular oxygen in the air matches phosphorescence in terms of energy levels and symmetry, phosphorescence is easily quenched by atmospheric oxygen. This causes the energy of the phosphorescent molecule's triplet state to transfer to oxygen. The molecular oxygen, excited by the phosphorescence energy, transitions from the triplet state to the singlet state. Singlet oxygen, with its higher energy than molecular oxygen, is more unstable and more prone to oxidizing organic compounds, damaging them. Since phosphorescence energy is not emitted as light but quenched by oxygen, it is difficult to detect in the presence of oxygen. Therefore, protecting phosphorescence from oxygen quenching is crucial. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a photochemical oxygen removal micelle, its preparation method, and its application. This invention prepares a photochemical oxygen removal micelle for protecting the excited triplet state of a luminescent compound. The core of this micelle is the hydrophobic end of a surfactant, encapsulating the luminescent compound, while the outer shell is the hydrophilic end. This polymeric micelle can achieve photochemical oxygen removal, thereby realizing efficient triplet-triplet annihilation photon upconversion in aqueous solutions under air conditions.

[0006] This invention is achieved through the following technical solution:

[0007] The first objective of this invention is to provide a photochemical oxygen scavenging micelle, comprising a surfactant, a luminescent compound, and a solvent; wherein the hydrophobic end of the surfactant in the photochemical oxygen scavenging micelle is coated with the luminescent compound; and wherein the luminescent compound comprises a photosensitizer and an annihilator, wherein the content of the annihilator is greater than or equal to 0.

[0008] In one embodiment of the present invention, one or more of the following conditions are satisfied:

[0009] 1) The surfactant is selected from one or more of F127, P123, and polyether compounds;

[0010] 2) The content of the surfactant is 2.5wt%-10wt%;

[0011] 3) The photosensitizer is selected from porphyrin photosensitizers and / or phthalocyanine photosensitizers.

[0012] In one embodiment of the present invention, the following steps are included:

[0013] (1) Dissolve the photosensitizer and the annihilation agent in a solvent to obtain a solution containing the luminescent compound, wherein the content of the annihilation agent is greater than or equal to 0;

[0014] (2) The surfactant is added to the solution containing the luminescent compound obtained in step (1) and dissolved by ultrasonication;

[0015] (3) Add water to the solution obtained in step (2), disperse by ultrasonication, and distill under reduced pressure at 40℃~60℃ to obtain the photochemical deoxygenating micelles.

[0016] In one embodiment of the present invention, the surfactant is selected from one or more of F127, P123 and polyether compounds.

[0017] The structural formula of P123 is shown below:

[0018]

[0019] In one embodiment of the present invention, the photosensitizer is selected from porphyrin photosensitizers and / or phthalocyanine photosensitizers; the solvent is selected from water and / or tetrahydrofuran.

[0020] A second objective of this invention is to provide a method for using photochemical deoxygenating micelles to protect the excited triplet state of luminescent compounds, comprising the following steps:

[0021] Photochemical oxygen-scavenging micelles containing a luminescent compound are irradiated with excitation light; the luminescent compound includes a photosensitizer and an annihilator, wherein the annihilator content is greater than or equal to 0.

[0022] In one embodiment of the present invention, the concentration of the photosensitizer is 5 × 10⁻⁶. -6 mol·L -1 ~5×10 -5 mol·L -1 The concentration of the annihilating agent is 5 × 10⁻⁶. -5 mol·L -1 ~2.5×10 -3 mol·L -1 .

[0023] In one embodiment of the present invention, the molar ratio of the photosensitizer to the annihilator is 1:0 to 1:50.

[0024] Furthermore, the molar ratio of the photosensitizer to the annihilator is 1:10 to 1:50.

[0025] In one embodiment of the present invention, the optical energy density of the excitation light is 15.3 mW·cm⁻¹. -2 ~120.7mW·cm -2 .

[0026] A third objective of this invention is to provide the application of the aforementioned photochemical deoxygenating micelles in triplet-triplet annihilation photon upconversion materials.

[0027] In one embodiment of the present invention, the method for using the photochemical oxygen-scavenging micelles to protect the excited triplet state of a photosensitizer includes the following steps:

[0028] (1) Dissolve the photosensitizer Pt(OEP) (octaethylporphyrin platinum), or Pt(OEP) and the annihilator DPA (9,10-diphenylanthracene) in tetrahydrofuran at a molar ratio of 1:0 to 1:50 to prepare a solution containing the desired compound (Pt(OEP) concentration is 1×10⁻⁶). - 5 mol·L -1 );

[0029] (2) Add surfactant F127 to the tetrahydrofuran solution in step 1 and sonicate for 5 to 10 minutes until F127 dissolves;

[0030] (3) Add a certain amount of water to the solution obtained in step 2 and ultrasonically disperse for 5 to 10 minutes;

[0031] (4) The solution obtained in step 3 was subjected to vacuum distillation at 40℃~60℃ to remove tetrahydrofuran, and micelles containing Pt(OEP) or Pt(OEP) / DPA were obtained (F127 content was 5wt%).

[0032] Mechanism of the invention:

[0033] The photochemical deoxygenation process of the photochemical deoxygenation micelles in this invention is analyzed as follows: Under illumination, Pt(OEP) (photosensitizer) absorbs light to generate an excited triplet state. Ground-state (triplet) oxygen molecules absorb the energy of the excited triplet state of Pt(OEP) to form excited-state (singlet) oxygen. The singlet oxygen reacts with F127 molecules to form peroxides, consuming oxygen molecules and achieving deoxygenation of the microenvironment within the micelles. A detailed mechanism diagram is attached. Figure 1 As shown.

[0034] The technical solution of the present invention has the following advantages compared with the prior art:

[0035] This invention provides a photochemical oxygen-removing micelle, its preparation method, and its applications. The TTA-UC process described in this invention must be carried out under anaerobic conditions. Traditionally, nitrogen replacement is mainly used for oxygen removal, which is time-consuming and labor-intensive, and it is difficult to achieve a completely anaerobic environment in practical applications. The photochemical oxygen-removing micelles prepared by this invention enable the application of upconversion systems in aerobic environments, expanding the applications of TTA-UC in fields such as bioimaging and sunlight utilization. Attached Figure Description

[0036] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings, wherein...

[0037] Figure 1 This is a diagram illustrating the photochemical oxygen removal mechanism of photochemical oxygen micelles in this invention;

[0038] Figure 2 This is a characterization diagram of the photochemical deoxygenation micelles in Example 1 of the present invention;

[0039] Figure 3 This refers to the phosphorescence emission spectrum of the micelle solution and the starch-potassium iodide experiment in Test Example 1 of this invention; wherein... Figure 3 -A represents the phosphorescence emission spectrum of Pt(OEP) in an air-saturated micelle solution; Figure 3 -B represents the experiment of starch-potassium iodide generated by peroxides during photochemical processes;

[0040] Figure 4 The emission spectrum and upconversion quantum efficiency of the colloid under laser excitation in air conditions are shown in Test Example 2 of this invention; wherein... Figure 4 -A represents the emission spectrum of Pt(OEP) / DPA under 532nm laser excitation; Figure 4 -B represents the upconversion quantum efficiency of Pt(OEP) / DPA under 532nm laser excitation;

[0041] Figure 5 The emission spectrum and upconversion quantum efficiency of the colloid under laser excitation under nitrogen conditions are shown in Test Example 2 of this invention; wherein... Figure 5 -A represents the emission spectrum of Pt(OEP) / DPA under laser excitation; Figure 5 -B represents the upconversion quantum efficiency of Pt(OEP) / DPA under laser excitation. Detailed Implementation

[0042] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0043] Example 1

[0044] This embodiment provides a photochemical oxygen-removing micelle, prepared by the following method:

[0045] (1) Dissolve the photosensitizer Pt(OEP) in tetrahydrofuran to prepare a photosensitizer solution, wherein the concentration of Pt(OEP) is 1×10⁻⁶. -5 mol·L -1 ;

[0046] (2) Add surfactant F127 to the photosensitizer solution obtained in step (1) and sonicate for 5 to 10 minutes until surfactant F127 dissolves;

[0047] (3) Add a certain amount of deionized water to the solution obtained in step (2) and ultrasonically disperse for 5 to 10 minutes;

[0048] (4) The dispersed solution obtained in step (3) is subjected to vacuum distillation at 40℃~60℃ to remove tetrahydrofuran, and micelles containing Pt(OEP) are used to protect the photochemical oxygen removal micelles excited triplet state of the photosensitizer, wherein the content of surfactant F127 is 5wt%.

[0049] The photochemical oxygen-scavenging micelles prepared in this embodiment for protecting the excited triplet state of the photosensitizer were characterized by dynamic light scattering, specifically as follows: Figure 2 As shown. By Figure 2 It can be seen that the particle size of the micelles ranges from 20 nm to 80 nm, with an average particle size of 26 nm.

[0050] Example 2

[0051] This embodiment provides a photochemical oxygen-removing micelle for protecting the excited triplet state of a photosensitizer, and the preparation method is as follows:

[0052] (1) Dissolve photosensitizer Pt(OEP) and annihilator DPA in tetrahydrofuran at a molar ratio of 1:10 to prepare a Pt(OEP) / DPA solution, wherein the concentration of Pt(OEP) is 1×10⁻⁶. -5 mol·L -1 ;

[0053] (2) Add surfactant F127 to the Pt(OEP) / DPA solution obtained in step (1) and sonicate for 8 minutes until surfactant F127 dissolves;

[0054] (3) Add a certain amount of deionized water to the solution obtained in step (2) and sonicate for 8 minutes;

[0055] (4) The solution obtained in step (3) was subjected to vacuum distillation at 40°C to remove tetrahydrofuran, and micelles containing Pt(OEP) / DPA were obtained, wherein the content of surfactant F127 was 5wt%.

[0056]

[0057] Example 3

[0058] This embodiment provides a photochemical oxygen-removing micelle for protecting the excited triplet state of a photosensitizer, and the preparation method is as follows:

[0059] (1) Dissolve photosensitizer Pt(OEP) and annihilator DPA in tetrahydrofuran at a molar ratio of 1:50 to prepare a Pt(OEP) / DPA solution, wherein the concentration of Pt(OEP) is 1×10⁻⁶. -5 mol·L -1 ;

[0060] (2) Add surfactant F127 to the Pt(OEP) / DPA solution obtained in step (1) and sonicate for 10 minutes until surfactant F127 dissolves;

[0061] (3) Add a certain amount of deionized water to the solution obtained in step (2) and ultrasonically disperse for 10 minutes;

[0062] (4) The solution obtained in step (3) was subjected to vacuum distillation at 60°C to remove tetrahydrofuran, and micelles containing Pt(OEP) / DPA were obtained, wherein the content of surfactant F127 was 5wt%.

[0063] Example 4

[0064] This embodiment provides a photochemical oxygen-removing micelle for protecting the excited triplet state of a photosensitizer, and the preparation method is as follows:

[0065] (1) Dissolve photosensitizer Pt(OEP) and annihilator DPA in tetrahydrofuran at a molar ratio of 1:30 to prepare a Pt(OEP) / DPA solution, wherein the concentration of Pt(OEP) is 1×10⁻⁶. -5 mol·L -1 ;

[0066] (2) Add surfactant F127 to the Pt(OEP) / DPA solution obtained in step (1) and sonicate for 5 minutes until surfactant F127 dissolves;

[0067] (3) Add a certain amount of deionized water to the solution obtained in step (2) and ultrasonically disperse for 5 minutes;

[0068] (4) The solution obtained in step (3) was subjected to vacuum distillation at 50°C to remove tetrahydrofuran, and micelles containing Pt(OEP) / DPA were obtained, wherein the content of surfactant F127 was 5wt%.

[0069] Test Example 1: Characterization of the photochemical deoxygenation properties of micelles

[0070] This test example uses the Pt(OEP)-containing micelles prepared in Example 1 for photochemical deoxygenation to protect the excited triplet state of the photosensitizer. When excited with 365nm UV light in air, phosphorescence emission of the Pt(OEP) micelles can be observed. The specific phosphorescence emission spectrum of Pt(OEP) in an air-saturated micelle solution is shown below. Figure 3 As shown in -A, by Figure 3The presence of -A indicates that the excited triplet state of Pt(OEP) is effectively protected. Adding a starch-potassium iodide solution to an irradiated Pt(OEP) micelle solution clearly shows that the starch-potassium iodide solution turns purple, as shown in the image. Figure 3 As shown in Figure -B, oxides are generated during the illumination process. The photochemical deoxygenation process of F127 micelles is analyzed as follows: Under illumination, Pt(OEP) (photosensitizer) absorbs light to generate an excited triplet state. Ground-state (triplet) oxygen molecules absorb the energy of the excited triplet state of Pt(OEP) to form excited-state (singlet) oxygen. The singlet oxygen reacts with F127 molecules to form peroxides, consuming oxygen molecules and achieving deoxygenation of the microenvironment within the micelles.

[0071] Test Example 2

[0072] This test example uses micelles containing Pt(OEP) / DPA from Example 4. This invention verifies upconversion in micelle solutions under air conditions. Figure 4 As shown in Figure -A, micelles containing Pt(OEP) / DPA, when excited by a 532 nm laser, exhibit upconversion emission of DPA at 430 nm, and as shown in Figure -A... Figure 4 As shown in -B, the upconversion quantum efficiency can reach a maximum of 5.9%.

[0073] To verify the effectiveness of micelle photochemical deoxygenation, the upconversion quantum efficiency of the Pt(OEP) / DPA micelles prepared in Example 4 was tested under nitrogen conditions. See details below. Figure 5 ;Depend on Figure 5 It can be seen that the upconversion quantum efficiency can reach 6.2%.

[0074] It is evident that the upconversion efficiency under air conditions is 95% of that under nitrogen deoxygenation conditions, indicating that F127 micelles have excellent photochemical deoxygenation capabilities.

[0075] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A photochemical oxygen-scavenging micelle, characterized in that, It includes surfactants, photosensitizers, annihilators, and solvents; the hydrophobic ends of the surfactants in the photochemical oxygen-scavenging micelles are coated with photosensitizers and annihilators; wherein the content of the annihilator is greater than 0; a concentration of 5 x 10 -6 mol L -1 ~5 x 10 -5 mol L -1 ; a concentration of 5 x 10 -5 mol L -1 ~2.5 x 10 -3 mol L -1 ; and the quencher is 9,10-diphenylanthracene. The surfactant is selected from F127 and P123; The photosensitizer is selected from porphyrin-based photosensitizers and / or phthalocyanine-based photosensitizers.

2. The photochemical oxygen-removing micelles according to claim 1, characterized in that, The content of the surfactant is 2.5wt%-10wt%.

3. A method for preparing photochemical oxygen-scavenging micelles, characterized in that, Includes the following steps: (1) Dissolve the photosensitizer and the annihilator in a solvent to obtain a solution containing the photosensitizer and the annihilator, wherein the content of the annihilator is greater than 0; (2) The surfactant is added to the solution containing photosensitizer and annihilator obtained in step (1) and dissolved by ultrasonication; (3) Add water to the solution obtained in step (2), disperse by ultrasonication, and distill under reduced pressure at 40℃~60℃ to obtain the photochemical deoxygenating micelles; The concentration of the photosensitizer is 5 × 10⁻⁶. -6 mol·L -1 ~5×10 -5 mol·L -1 The concentration of the annihilating agent is 5 × 10⁻⁶. -5 mol·L -1 ~2.5×10 -3 mol·L -1 The annihilating agent is 9,10-diphenylanthracene. The surfactant is selected from F127 and P123; The photosensitizer is selected from porphyrin-based photosensitizers and / or phthalocyanine-based photosensitizers.

4. The preparation method according to claim 3, characterized in that, In step (1), the solvent is selected from water and / or tetrahydrofuran.

5. A method for using photochemical oxygen-scavenging micelles to protect the excited triplet states of photosensitizers and annihilators, characterized in that, Includes the following steps: Photochemical oxygen-scavenging micelles containing a photosensitizer and an annihilator are irradiated with excitation light; wherein the content of the annihilator is greater than 0. The photochemical oxygen scavenging micelles include a surfactant, a photosensitizer, an annihilator, and a solvent; the hydrophobic end of the surfactant in the photochemical oxygen scavenging micelles is coated with the photosensitizer and the annihilator. The concentration of the photosensitizer is 5 × 10⁻⁶. -6 mol·L -1 ~5×10 -5 mol·L -1 The concentration of the annihilating agent is 5 × 10⁻⁶. -5 mol·L -1 ~2.5×10 -3 mol·L -1 ; The annihilating agent is 9,10-diphenylanthracene; The surfactant is selected from F127 and P123; The photosensitizer is selected from porphyrin-based photosensitizers and / or phthalocyanine-based photosensitizers.

6. The method according to claim 5, characterized in that, The molar ratio of photosensitizer to annihilator is 1:10 to 1:

50.

7. The method according to claim 5, characterized in that, The light energy density of the excitation light is 15.3 mW·cm⁻¹. -2 ~120.7 mW·cm -2 .

8. The application of the photochemical deoxygenating micelles according to claim 1 in triplet-triplet annihilation photon upconversion materials.

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