A temperature-responsive fluorescent nanomaterial, its preparation method and application

Abstract

This invention provides temperature-responsive fluorescent nanomaterials, their preparation methods, and applications. The temperature-responsive fluorescent nanomaterials are nanoparticles formed from the compound TPE-CSO in an aqueous phase. The TPE-CSO compound comprises hydrophobic dinuclear fluorescent groups tetraphenylethylene (TPE) and cyanostyl styrene (CS) as the parent core, and temperature-responsive oligoethylene glycol (OEG) linked by benzyloxy groups as the hydrophilic chain. Furthermore, this invention also provides a temperature-responsive continuous light-harvesting system. This system constructs a reversible temperature-responsive light-harvesting system by loading the temperature-responsive fluorescent nanomaterials with hydrophobic dyes Rh6G and SR101, utilizing fluorescence resonance energy transfer. This system, as a catalyst for photocatalytic oxidative cracking reactions, exhibits a catalytic efficiency of 97%. This technology has great potential in preparing tunable luminescent catalytic materials and simulating the influence of temperature on photosynthesis, demonstrating broad application prospects.

Description

Technical Field

[0001] This invention relates to the fields of organic light-emitting materials and supramolecular photocatalysis, and more specifically, to a temperature-responsive fluorescent nanomaterial that mimics the photosynthesis of plants in nature, its preparation method, and its application in photocatalytic oxidative pyrolysis. Background Technology

[0002] In photosynthesis in nature, continuous energy transfer is the key mechanism for efficiently delivering solar energy to the reaction center, ensuring the stable conversion and utilization of light energy. Artificial light-harvesting systems, as an innovative technology mimicking this process, have attracted widespread attention in recent years for solar energy capture, transmission, and utilization. Light-harvesting systems are the primary link in photosynthesis, and their working principles have been thoroughly studied, further driving the construction of artificial simulation systems. Supramolecular self-assembly provides an effective strategy for constructing efficient artificial light-harvesting systems. This strategy not only offers an ideal way to improve light-harvesting efficiency but also demonstrates enormous application potential. Artificial light-harvesting systems based on supramolecular self-assembly have made significant progress at the nanoscale, exhibiting extremely high donor / acceptor ratios, excellent energy transfer efficiency, and enhanced antenna effects, demonstrating their significant advantages as efficient light-harvesting systems.

[0003] Another important characteristic of photosynthesis is the significant impact of temperature on its efficiency. Temperature changes not only affect natural photosynthesis but also play a crucial role in the efficiency and selectivity of artificial photocatalytic reactions. Photocatalytic processes typically rely on the dynamic regulation of reactant molecular structure and environmental conditions, and temperature fluctuations often cause changes in catalytic performance. Molecules with temperature-responsive properties, such as oligoethylene glycol (OEG) groups, have attracted widespread attention due to their unique hydrophilicity and temperature responsiveness. By combining OEG groups with other functional groups to form amphiphilic molecules, these molecules can self-assemble into stable nanoaggregates in aqueous media and exhibit Low Critical Solution Temperature (LCST) behavior.

[0004] Thermosensitive photocatalytic systems designed based on these characteristics can provide new ways to regulate photocatalytic reactions and simulate the effects of temperature changes on chemical reactions. Although research on thermosensitive photocapture catalytic systems is still in its early stages, especially thermosensitive photocatalytic systems with continuous energy transfer capabilities, breakthroughs in this field undoubtedly have significant research value and broad application prospects. Summary of the Invention

[0005] This invention provides a biomimetic temperature-responsive fluorescent nanomaterial and applies it to photocatalytic oxidative pyrolysis reactions. The nanomaterial includes the compound TPE-CSO, which possesses aggregation-induced emission (AIE) properties and amphiphilicity, enabling it to self-assemble into fluorescent nanoparticles in aqueous solution. Based on this, a temperature-responsive continuous light-harvesting system exhibits tunable fluorescence emission and thermosensitive properties. Furthermore, the oligoethylene glycol chain endows TPE-CSO with tunable low critical solution temperature behavior, combined with continuous fluorescence resonance energy transfer (FRET) and LCST properties, thus enabling the system to exhibit temperature-sensitive performance. Under illumination, the system continuously generates reactive oxygen species (ROS) and demonstrates an ultra-high catalytic efficiency of 97% in photocatalytic oxidative pyrolysis reactions. The reaction yield gradually decreases with increasing temperature, and the light-harvesting system maintains high catalytic efficiency even after 20 cycles between 25°C and 60°C. This system effectively simulates the phenomenon in nature where photosynthesis is inhibited in high temperatures and recovers in cooler weather. This system not only provides a new means of regulating photocatalytic reactions, but also provides an important reference for simulating the environmental adaptability of natural photosynthesis, and has broad application prospects.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows:

[0007] The first aspect of this invention provides a temperature-responsive fluorescent nanomaterial, which is nanoparticles formed from the compound TPE-CSO in an aqueous phase; the compound TPE-CSO comprises hydrophobic dinuclear fluorescent groups tetraphenylethylene (TPE) and cyanostyrene (CS) as a core, and temperature-responsive oligoethylene glycol (OEG) linked by benzyloxy groups as a hydrophilic chain; the structural formula of the TPE-CSO is shown in Formula I:

[0008]

[0009] Furthermore, in this temperature-responsive fluorescent nanomaterial, the concentration of the compound TPE-CSO in deionized water is greater than 42 μM.

[0010] Furthermore, the cloud point temperature of the temperature-responsive fluorescent nanomaterial at a concentration of 200 μM is 35.3 °C. When the temperature is below the cloud point temperature, the solution of the temperature-responsive fluorescent nanomaterial remains transparent; while when the temperature is above the cloud point temperature, the solution of the temperature-responsive fluorescent nanomaterial becomes cloudy. The cloud point temperature of the temperature-responsive fluorescent nanomaterial decreases with increasing concentration. When the concentration increases from 100 μM to 500 μM, the cloud point temperature decreases from 38.0 °C to 33.6 °C.

[0011] A second aspect of the present invention provides a method for preparing the temperature-responsive fluorescent nanomaterial as described above, the method comprising: nucleophilically substituting compound a and compound b to obtain the compound TPE-CSO; the structural formula of compound a is shown in Formula II:

[0012]

[0013] The structural formula of compound b is shown in Formula III:

[0014]

[0015] Furthermore, the preparation method specifically includes the following steps: under a N2 atmosphere, an acetonitrile solution containing K2CO3 and compound a is added to a reaction vessel; subsequently, an acetonitrile solution containing compound b is added dropwise to the reaction vessel to obtain a mixed system; the mixed system is refluxed for 36 hours; after the reaction is completed, the mixture obtained is cooled to room temperature and concentrated under reduced pressure to obtain a crude product; the crude product is purified by silica gel column chromatography to obtain a yellow-green viscous oily product, which is the compound TPE-CSO.

[0016] Furthermore, in this preparation method, the amounts of each component are used in the following proportions: in the acetonitrile solution containing K2CO3 and compound a, K2CO3 is 0.35 g and 2.6 mmol; compound a is 0.80 g and 1.7 mmol; acetonitrile is 18 mL; in the acetonitrile solution containing compound b, compound b is 1.23 g and 1.9 mmol; acetonitrile is 6 mL; the molar ratio of compound a, compound b, and K2CO3 is 1:(1.1-1.2):(1.4-1.6); preferably, the eluent volume ratio of the column chromatography is increased from 200:1 to 50:1 by increasing DCM:MeOH.

[0017] Furthermore, the preparation method further includes synthesizing compound a and compound b separately; preferably, the synthesis method of compound a is as follows: triphenyl bromoethylene and 4-methoxyphenylboronic acid are coupled by Suzuki-Miyaura reaction, and then demethylated with boron tribromide to obtain compound a; preferably, the synthesis method of compound b is as follows: starting from triethylene glycol monomethyl ether, the hydroxyl group is first converted to a sulfonyl group, and then reacted with methyl gallate, and after reduction and bromination, compound b is obtained.

[0018] A third aspect of this invention provides a temperature-responsive continuous light-harvesting system, wherein the system uses a hydrophobic dye rhodamine 6G (Rh6G) as a first-step energy acceptor (A1), sulforhodamine 101 (SR101) as a second-step energy acceptor (A2), and a temperature-responsive fluorescent nanomaterial as described in any one of claims 1 to 3 as a donor (D); wherein the molar ratio of the donor, the first-step energy acceptor, and the second-step energy acceptor is 1000:20:0 to 1000:20:20. The light-harvesting system can generate reactive oxygen species (ROS). The light-harvesting system ([TPE-CSO] = 50 μM) is added to 4 mL of 0.5 mM solutions of 9,10-anthratridiylbis(methylene)diglutaric acid (ABDA) and N,N,N',N'-tetramethylphenylenediamine (TMPD). Under UV irradiation, the UV-Vis absorption spectrum is tested over time to confirm the presence of singlet oxygen and superoxide radicals. 1 O2 and O2 ·- The generation of reactive oxygen species such as )

[0019] The fourth aspect of the present invention provides the application of the temperature-responsive continuous light-harvesting system described above in the field of photocatalytic oxidative pyrolysis reaction.

[0020] Furthermore, the temperature-responsive continuous light-harvesting system is subjected to a temperature-responsive photocatalytic oxidation pyrolysis reaction, comprising the following steps: the temperature-responsive continuous light-harvesting system and 1,1-stilbene are sequentially added to water and reacted at room temperature for 12 hours under ultraviolet light irradiation; the temperature-responsive continuous light-harvesting system and 1,1-stilbene are sequentially added to water and reacted at 30°C, 40°C, 50°C, and 60°C respectively under ultraviolet light irradiation for 12 hours, with the catalytic yield gradually decreasing as the temperature increases; the temperature-responsive continuous light-harvesting system is added to water and cycled at 25°C and 60°C for 5, 10, 15, and 20 times respectively, before adding 1,1-stilbene and reacting at room temperature for 12 hours under ultraviolet light irradiation, still exhibiting catalytic efficiency.

[0021] Compared with the prior art, the present invention has at least the following beneficial effects:

[0022] 1. The compound synthesis method involved in this invention is simple, the raw materials are inexpensive and readily available, the molecular preparation cost is low, and it has high economic efficiency and operability.

[0023] 2. This invention successfully constructs a supramolecular biomimetic temperature-responsive continuous light-harvesting system. This system not only comprehensively simulates the continuous energy transfer process in natural photosynthesis but also effectively reflects the impact of temperature changes on catalytic efficiency. The developed system exhibits good temperature response reversibility and can be applied to photocatalytic oxidation-cracking reactions, precisely regulating catalytic efficiency by controlling the temperature.

[0024] 3. The compound TPE-CSO features an ingenious molecular design, combining a hydrophobic end with AIE (Alternating External Ionization) effect and a hydrophilic end with LCST (Low Temperature Stability) behavior, exhibiting the dual benefits of an amphiphilic molecule. This design not only enables self-assembly in the aqueous phase but also allows for a sensitive response to temperature changes, enhancing the molecule's functional diversity.

[0025] 4. In the design of the TPE-CSO compound, the AIE (Alternating Induction of Ionization) property is stably manifested through the hydrophobic TPE and CS binuclear fluorophores, while the hydrophilic OEG group endows the molecule with LCST (Liquid Chromium-Stasis-Reducing) behavior. In the aqueous phase, TPE-CSO can self-assemble into regular nanospheres. When the temperature rises, the hydrogen bonds between the OEG group and water molecules are broken, causing the hydrophobic ends (TPE and CS units) to loosen, thereby reducing the AIE effect and fluorescence intensity. This design is inspired by the phenomenon of "temperature-induced disassembly in photosynthesis, thereby inhibiting photosynthetic efficiency" in nature, and is highly biomimetic.

[0026] 5. The assembly of compound TPE-CSO can achieve two-step continuous energy transfer. After the two energy transfers are completed, when the donor / acceptor ratio reaches D / A1 / A2 = 1000:20:20, the energy transfer efficiency is still as high as 44.0%, demonstrating excellent energy transfer performance and ensuring the efficient operation of the light-harvesting system.

[0027] 6. A temperature-responsive continuous light-harvesting system based on the compound TPE-CSO can serve as a photosensitizer, enabling precise control of the photocatalytic process through temperature regulation. This system also exhibits excellent temperature reversibility, maintaining high catalytic efficiency even after more than 20 temperature cycles. This provides an innovative approach to high-efficiency photocatalytic reactions under temperature control and has broad application prospects. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the technical solution of the present invention;

[0029] Figure 2 The image shows the 1H NMR spectrum of the compound TPE-CSO.

[0030] Figure 3 The image shows the carbon NMR spectrum of the compound TPE-CSO.

[0031] Figure 4 This is the high-resolution mass spectrum of compound TPE-CSO;

[0032] Figure 5 This represents the critical aggregation concentration (CAC) of the compound TPE-CSO.

[0033] Figure 6 System temperature response diagram for transmittance experiment of compound TPE-CSO;

[0034] Figure 7 The temperature-response fluorescence emission spectrum of compound TPE-CSO;

[0035] Figure 8 This is a two-step energy transfer diagram of compound TPE-CSO;

[0036] Figure 9 The diagram shows the temperature-responsive photocatalytic oxidation pyrolysis reaction of compound TPE-CSO. Detailed Implementation

[0037] The following embodiments are merely some, not all, of the embodiments of the present invention. Therefore, the detailed descriptions of the embodiments provided below are not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0038] In this invention, unless otherwise specified, all equipment and raw materials are commercially available or commonly used in the industry. The methods described in the following embodiments are conventional methods in the art, unless otherwise specified.

[0039] This invention provides a temperature-responsive fluorescent nanomaterial, which is based on the supramolecular self-assembly of TPE-CSO molecules in an aqueous phase. The structural formula of the compound TPE-CSO is as follows:

[0040]

[0041] The compound TPE-CSO was prepared by nucleophilic substitution of compounds a and b, and the reaction equation is as follows:

[0042]

[0043] Compound a is Compound b is

[0044] The method for preparing this temperature-responsive fluorescent nanomaterial includes the following steps: Under a N2 atmosphere, an acetonitrile (18 mL) solution of K2CO3 (0.35 g, 2.6 mmol) and compound a (0.80 g, 1.7 mmol) is added to a three-necked flask. Subsequently, an acetonitrile (6 mL) solution of compound b (1.23 g, 1.9 mmol) is slowly added dropwise to the flask. The resulting mixture is refluxed for 36 h. After the reaction is complete, the reaction mixture is cooled to room temperature and concentrated under reduced pressure. The crude product is purified by silica gel column chromatography to obtain a yellow-green viscous oily compound TPE-CSO (1.00 g, 0.95 mmol, 56%). TPE-CSO is added to deionized water, where it self-assembles into nanoparticles driven by hydrophilic-hydrophobic interactions.

[0045] This invention also provides a temperature-responsive continuous light-harvesting system. This system uses a hydrophobic dye Rh6G as acceptor 1 (A1), SR101 as acceptor 2 (A2), and TPE-CSO as donor (D). The molar ratio of donor to acceptor, D / A1, is 1000:1 to 1000:20, and the ratio of D / A1 / A2 is 1000:20:0 to 1000:20:20. It can be seen that this system constructs a reversible temperature-responsive light-harvesting system by loading hydrophobic dyes Rh6G and SR101 onto temperature-responsive fluorescent nanomaterials and utilizing fluorescence resonance energy transfer. As a catalyst for photocatalytic oxidative decomposition reactions, this system exhibits a catalytic efficiency of 97%.

[0046] The temperature-responsive continuous light-harvesting system is subjected to a temperature-responsive photocatalytic oxidation pyrolysis reaction, exhibiting an excellent catalytic efficiency of 97%; the process includes the following steps:

[0047] Step 1: Add the temperature-responsive continuous light-harvesting system ([TPE-CSO] = 100 μM) and 1,1-stilbene to water (20 mL) in sequence, and react at room temperature for 12 h under UV irradiation;

[0048] Step 2: Add the light-harvesting system and 1,1-stilbene sequentially to water (20 mL), and react under UV light at 30°C, 40°C, 50°C and 60°C for 12 h respectively. The yield gradually decreases as the temperature increases.

[0049] Step 3: Add the light-harvesting system to water (20 mL) and cycle it 5, 10, 15 and 20 times at 25℃ and 60℃ respectively. Then add 1,1-stilbene and react at room temperature for 12 hours under UV irradiation. It still has excellent catalytic efficiency.

[0050] Figure 1This is a schematic diagram of the technical route of the present invention, illustrating the molecular structure, self-assembly process, and LCST behavior of compound TPE-CSO, as well as the construction of a reversible temperature-responsive secondary energy transfer light-harvesting system and the photocatalytic oxidative pyrolysis reaction of 1,1-stilbene. Compound TPE-CSO, composed of hydrophobic TPE and CS groups and hydrophilic oligoethylene glycol chains, exhibits both AIE and LCST properties. As the temperature rises, the aqueous solution of TPE-CSO gradually changes from clear to turbid; when the temperature drops back to its original state, the solution returns to its original clear state. Furthermore, the constructed secondary energy transfer light-harvesting system and photocatalytic oxidation reaction also exhibit reversible temperature response. As the temperature rises, the fluorescence intensity of the light-harvesting system gradually decreases, while the photocatalytic reaction shows a gradual decrease in catalytic efficiency with increasing temperature. However, when the temperature drops back to its original level, it exhibits a highly efficient catalytic effect.

[0051] Example

[0052] Example 1

[0053] (1) Synthesis of TPE-CSO: Under a N2 atmosphere, K2CO3 (0.35 g, 2.6 mmol), compound a (0.80 g, 1.7 mmol), and acetonitrile (18 mL) solution were added to a three-necked flask. Subsequently, compound b (1.23 g, 1.9 mmol) in acetonitrile (6 mL) solution was slowly added dropwise to the flask. The resulting mixture was refluxed for 36 h. After the reaction was completed, the reaction mixture was cooled to room temperature and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography to give a yellow-green viscous oily compound TPE-CSO (1.00 g, 0.95 mmol, 56%).

[0054] The 1H NMR spectrum of compound TPE-CSO is as follows: Figure 2 As shown: 1 H NMR (300MHz, CDCl3) δ (ppm) = 7.63 (d, J = 6.0Hz, 2H, Ar-H), 7.56 (d, J = 6.0Hz, 2H, Ar-H), 7.30 (s ,1H,-CH=C-),7.13-7.09(m,11H,Ar-H),7.07-6.98(m,8H,Ar-H),6.66(s,2H,Ar-H),4.98(s, 2H,-CH2-),4.17-4.16(m,6H,-CH2-),3.85(s,4H,-CH2-),3.79(s,2H,-CH2-),3.73-3.72(m, 6H,-CH2-),3.67-3.63(m,12H,-CH2-),3.55-3.53(m,6H,-CH2-),3.38(d,J=3.0Hz,9H,-CH3).

[0055] The carbon NMR spectrum of compound TPE-CSO is as follows: Figure 3 As shown: 13 C NMR (75MHz, CDCl3): δ (ppm) = 159.5, 153.0, 146.2, 143.5, 143.4, 143.3, 142.3, 140.2, 140.1, 138.4, 132.0, 131.5, 131.4, 128.6, 128. 0,127.9,127.8,127.6,127.4,127.0,126.8,118.4,115.4,110.2,107.3,72.4,72.0,70.9,70.8,70.7,70.7,70.3,69.8,69.0,59.1.

[0056] High-resolution mass spectra of compound TPE-CSO, such as Figure 4 As shown: HRMS(ESI)m / z:calcd for C 63 H 73 NO 13 [M+Na] + =1074.4974,found=1074.4964.

[0057] Based on the above experimental characterization, the structure of compound TPE-CSO was determined to be:

[0058]

[0059] (2) The compound TPE-CSO undergoes self-assembly in deionized water through hydrophilic-hydrophobic interactions. The transmittance experiment determined that the critical aggregation concentration of TPE-CSO is 42 μM, meaning that TPE-CSO assembles into nanoparticles above this concentration.

[0060] The first characteristic of compound TPE-CSO is that it is an amphiphilic molecule, containing an OEG group as the hydrophilic end and TPE and CS dual fluorescent groups as the hydrophobic end. Above the critical aggregation concentration (CAC, which was determined to be 42 μM by transmittance experiments), TPE-CSO forms spherical nanoassemblies driven by hydrophilic-hydrophobic interactions. See [link to CAC determination details] for details. Figure 5 ,in Figure 5 (a) represents the transmittance of TPE-CSO in aqueous solution at 2-256 μM. Figure 5 (b) The critical aggregation concentration of TPE-CSO is 42 μM.

[0061] (3) Compound TPE-CSO exhibits significant temperature response characteristics due to the presence of temperature-responsive OEG (oligoethylene glycol ether) units. A 200 μM aqueous solution of TPE-CSO was prepared, and its cloud point temperature under the specified conditions was determined to be 35.3 °C by transmittance test.

[0062] The second characteristic of the compound TPE-CSO is its excellent water solubility. At low temperatures, the oxygen atoms in its groups form a hydrogen bond network with water, creating a homogeneous phase. However, as the temperature increases, these hydrogen bonds break, the molecules transform from hydrophilic to hydrophobic, and phase separation occurs, resulting in a cloudy solution. The temperature at which the solution's transmittance drops to half of its original transmittance is called the "cloud point temperature," also known as the LCST, thus giving TPE-CSO its temperature-responsive properties. See also Figure 6 , Figure 6 The system temperature response diagram is shown in the TPE-CSO transmittance experiment. Figure 6 (a) is a diagram showing the cloud point determination. Figure 6 (b) is a temperature response cycle diagram.

[0063] Furthermore, the temperature response exhibits good reversibility, maintaining stable performance even after more than 20 heating / cooling cycles. Correspondingly, the fluorescence emission also shows good reversibility with temperature fluctuations.

[0064] A third characteristic of the compound TPE-CSO is its thermoresponsive fluorescence, exhibiting different aggregation forms and energy radiative forms in water during the heating / cooling transition. When the solution is at room temperature, TPE-CSO molecules self-assemble into ordered nanospheres with tightly packed TPE and CS units, significantly restricting intramolecular motion and dissipating energy primarily through radiation, resulting in strong emission with a maximum peak at 508 nm. Conversely, as the temperature increases, the molecules transition from hydrophilic to hydrophobic, and these tightly packed TPE units become looser, further increasing the non-radiative energy dissipation and leading to decreased fluorescence. Ultimately, when the temperature rises to 60.0 °C, the emission intensity decreases by 79% compared to the initial intensity. Notably, this temperature-responsive fluorescence attenuation of TPE-CSO is reversible, rapidly recovering fluorescence upon cooling to room temperature. See also Figure 7 , Figure 7 The image shows the temperature-response fluorescence emission pattern of TPE-CSO, where... Figure 7 (e) is a bar chart showing the fluorescence variation with temperature. Figure 7 (f) is the temperature response cycle diagram.

[0065] Example 2

[0066] In this embodiment, the supramolecular polymer formed by compound TPE-CSO is used as the energy donor D, the hydrophobic fluorescent dye Rh6G is used as the acceptor A1, and SR101 is used as the acceptor A2. The preparation method is as follows:

[0067] Firstly, the preparation of light-harvesting nanoparticles:

[0068] Prepare a 100 μM aqueous solution of TPE-CSO, and prepare a donor-acceptor aqueous solution with D / A1 / A2 = 1000 / 20 / 20 by loading Rh6G and SR101. Sonicate for 3 min with shaking during the process, and measure the fluorescence intensity of the sample using a fluorescence spectrophotometer.

[0069] The preparation methods for the following solution ratios (D / A1 / A2) of 1000 / 20 / 6, 1000 / 20 / 8, 1000 / 20 / 10, 1000 / 20 / 12, 1000 / 20 / 14, 1000 / 20 / 16, and 1000 / 20 / 20 are the same as described above. Their combined fluorescence spectra are shown below. Figure 8 As shown.

[0070] The fourth characteristic of the compound TPE-CSO is that its hydrophobic binuclear TPE and CS groups are aggregation-induced emission (FRET) groups. Therefore, TPE-CSO forms nanoparticles, resulting in aggregation-induced fluorescence enhancement (FRET). This provides a prerequisite for constructing an artificial light-harvesting system. By loading the hydrophobic dye Rh6G as acceptor A1, SR101 as acceptor A2, and the TPE-CSO group as energy donor D, when the dye molecules are encapsulated within the limited space of the nanoparticles, the distance between the donor and acceptor is sufficiently close, creating sufficient conditions for FRET to occur. Studies of the light-harvesting performance of this system revealed a good overlap between the absorption spectrum of Rh6G and the emission spectrum of TPE-CSO, and also a good overlap between the absorption spectrum of SR101 and the emission spectrum of TPE-CSO / Rh6G. Under the acceptor-donor ratio (D / A1 / A2 = 1000:40:40), the single-pass energy transfer efficiency (Φ) is [not specified]. ET The secondary energy transfer efficiency is as high as 78.3%, and the secondary energy transfer efficiency (Φ) is as high as 78.3%. ET It can reach as high as 44.0%. See also Figure 8 , Figure 8 The diagram shows the two-step energy transfer sequence of TPE-CSO, where... Figure 8 (a) is the absorption-emission overlap diagram of TPE-CSO and Rh6G. Figure 8 (b) is the light spectrum of a single energy transfer. Figure 8 (c) is the absorption-emission overlap diagram of TPE-CSO / Rh6G and SR101. Figure 8(d) shows the secondary energy transfer light spectrum. In this embodiment, the ultrasonic instrument used is a commonly used laboratory ultrasonic cleaner with a frequency of 40 kHz.

[0071] Secondly, energy transfer efficiency calculation:

[0072] The fluorescence spectra of TPE-CSO and TPE-CSO / Rh6G / SR101 were measured under 378 nm excitation.

[0073] Energy transfer efficiency (Φ) ET ) Calculated using equation S1:

[0074] Φ ET =1-I DA / I D

[0075] Among them I DA and I D The fluorescence intensities at 562 nm for TPE-CSO / Rh6G / SR101 and TPE-CSO / Rh6G respectively when excited at 378 nm, where [TPE-CSO] = 1.0 × 10⁻⁶. -4 mol / L, [Rh6G]=2.0×10 -6 mol / L. [SR101]=2.0×10 -6 mol / L. Substituting the data into formula S1, we get D / A1 / A2 = 1000 / 20 / 20, resulting in an energy transfer efficiency of 44.0%.

[0076] The energy transfer efficiency for other proportions was calculated using the formula above.

[0077] Example 3

[0078] Temperature-responsive photocatalytic reaction of compound TPE-CSO.

[0079] Step 1: Using a pipette, sequentially add TPE-CSO aqueous solution (D, 100 μL, 20 mM), Rh6G DMSO solution (A1, 20 μL, 2.0 mM), and SR101 DMSO solution (A2, 8 μL, 5.0 mM) to a 50 mL round-bottom flask, followed by 20 mL of deionized water. After sonication for 5 min, add 1,1-stilbene (180 μL), and react at room temperature under UV irradiation for 12 h, ultimately producing the oxidative pyrolysis product benzophenone, with a catalytic efficiency as high as 97%.

[0080] Step 2: The prepared photosensitizer (TPE-CSO / Rh6G / SR101) aqueous solution was placed in different temperature environments (25℃, 30℃, 40℃, 50℃ and 60℃) for 12h. The experimental results showed that the catalytic efficiency gradually decreased with increasing temperature.

[0081] Step 3: The prepared photosensitizer (TPE-CSO / Rh6G / SR101) aqueous solution was repeatedly heated and cooled between 25°C and 60°C (5, 10, 15 and 20 times), and the catalytic efficiency remained at an ultra-high level (≥90%).

[0082] It should be noted that the fifth characteristic of compound TPE-CSO is that, after continuous light capture (TPE-CSO / Rh6G / SR101), it can act as a photosensitizer, efficiently generating reactive oxygen species, including singlet oxygen and superoxide radicals, under ultraviolet light irradiation. 1 O2 and O2 ·- This study demonstrated superior catalytic performance for the photocatalytic oxidative cracking of 1,1-stilbene. The catalytic efficiency was significantly affected by temperature: at 25°C, the reaction yield reached as high as 97%, but the efficiency gradually decreased with increasing temperature, reaching only 27% at 60°C. Furthermore, the catalytic reaction exhibited excellent temperature reversibility. After repeated heating and cooling cycles of 5, 10, 15, and 20 times between 25°C and 60°C, continuous LHS aqueous solutions maintained an ultra-high catalytic efficiency (≥90%). See also... Figure 9 , Figure 9 The temperature-responsive photocatalytic oxidation pyrolysis reaction of TPE-CSO, wherein Figure 9 (a) Detection of ABDA as a trapping agent under different conditions 1 The generation of O2, Figure 9 (b) Detection of O2 under different conditions using TMPD as a capture agent ·- The generation, Figure 9 (c) is a bar chart showing the efficiency of the photocatalytic reaction at different reaction temperatures (25℃, 30℃, 40℃, 50℃, 60℃). Figure 9 (d) is a bar chart showing the catalytic efficiency of the continuous light-harvesting system after heating / cooling cycles at 25 °C and 60 °C (5, 10, 15, 20 times).

[0083] The above are merely preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A temperature-responsive fluorescent nanomaterial, characterized in that, The temperature-responsive fluorescent nanomaterial is a nanoparticle formed from the compound TPE-CSO in an aqueous phase. The compound TPE-CSO comprises a hydrophobic dinuclear fluorescent group tetraphenylethylene and cyanostyrene as the parent core, and a temperature-responsive oligoethylene glycol linked by a benzyloxy group as the hydrophilic chain. The structural formula of the TPE-CSO is shown in Formula I:

2. The temperature-responsive fluorescent nanomaterial according to claim 1, characterized in that, In this temperature-responsive fluorescent nanomaterial, the concentration of the compound TPE-CSO in deionized water is greater than 42 μM.

3. The temperature-responsive fluorescent nanomaterial according to claim 2, characterized in that, The temperature-responsive fluorescent nanomaterial has a cloud point temperature of 35.3°C at a concentration of 200 μM. When the temperature is below the cloud point temperature, the solution of the temperature-responsive fluorescent nanomaterial remains transparent; however, when the temperature is above the cloud point temperature, the solution of the temperature-responsive fluorescent nanomaterial becomes cloudy. The cloud point temperature of the temperature-responsive fluorescent nanomaterial decreases with increasing concentration; when the concentration increases from 100 μM to 500 μM, the cloud point temperature decreases from 38.0 °C to 33.6 °C.

4. The method for preparing temperature-responsive fluorescent nanomaterials as described in any one of claims 1 to 3, characterized in that, The preparation method includes: nucleophilic substitution of compound a and compound b to obtain the compound TPE-CSO; The structural formula of compound a is shown in Formula II: The structural formula of compound b is shown in Formula III:

5. The method for preparing temperature-responsive fluorescent nanomaterials according to claim 4, characterized in that, The preparation method specifically includes the following steps: Under a nitrogen atmosphere, an acetonitrile solution containing K2CO3 and compound a was added to a reaction vessel; subsequently, an acetonitrile solution containing compound b was added dropwise to the reaction vessel to obtain a mixed system; the mixed system was refluxed for 36 hours; after the reaction was completed, the resulting mixture was cooled to room temperature and concentrated under reduced pressure to obtain a crude product; the crude product was purified by silica gel column chromatography to obtain a yellow-green viscous oily product, which is the compound TPE-CSO.

6. The method for preparing temperature-responsive fluorescent nanomaterials according to claim 5, characterized in that, In this preparation method, the amounts of each component are used in the following proportions: In an acetonitrile solution containing K2CO3 and compound a, the concentration of K2CO3 is 0.35 g and the concentration is 2.6 mmol. Compound a was 0.80 g, 1.7 mmol; acetonitrile was 18 mL; In an acetonitrile solution containing compound b, the concentration of compound b is 1.23 g (1.9 mmol); the concentration of acetonitrile is 6 mL. The molar ratio of compound a, compound b, and K2CO3 is 1:(1.1~1.2):(1.4~1.6); The eluent volume ratio for column chromatography was increased from 200:1 to 50:1 using the DCM:MeOH ratio.

7. The method for preparing temperature-responsive fluorescent nanomaterials according to claim 5, characterized in that, The preparation method further includes synthesizing compound a and compound b separately; The method for synthesizing compound a is as follows: triphenyl bromoethylene and 4-methoxyphenylboronic acid undergo a Suzuki-Miyaura coupling reaction, followed by demethylation with boron tribromide to obtain compound a; The method for synthesizing compound b is as follows: starting from triethylene glycol monomethyl ether, the hydroxyl group is first converted to a sulfonyl group, then reacted with methyl gallate, and after reduction and bromination, compound b is obtained.

8. A temperature-responsive continuous light harvesting system, characterized in that, The temperature-responsive continuous light-harvesting system uses the hydrophobic dye Rhodamine 6G as the first-step energy acceptor, sulforhodamine 101 as the second-step energy acceptor, and the temperature-responsive fluorescent nanomaterial as described in any one of claims 1 to 3 as the donor; wherein the molar ratio of the donor, the first-step energy acceptor, and the second-step energy acceptor is 1000:20:0 to 1000:20:

20.

9. The application of the temperature-responsive continuous light-harvesting system as described in claim 8 in the field of photocatalytic oxidative cracking reaction.

10. The application as described in claim 9, characterized in that, The temperature-responsive continuous light-harvesting system is subjected to a temperature-responsive photocatalytic oxidation pyrolysis reaction, comprising the following steps: The temperature-responsive continuous light-harvesting system and 1,1-stilbene were added to water in sequence and reacted at room temperature for 12 hours under ultraviolet light irradiation. The temperature-responsive continuous light-harvesting system and 1,1-stilbene were added to water in sequence and reacted for 12 h at 30 °C, 40 °C, 50 °C and 60 °C under ultraviolet light irradiation. The yield gradually decreased with increasing temperature. The temperature-responsive continuous light-harvesting system was added to water and cyclicated at 25°C and 60°C for 5, 10, 15 and 20 cycles respectively. Then, 1,1-stilbene was added, and the reaction was carried out at room temperature for 12 hours under UV irradiation. The system still maintained catalytic efficiency.

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