Phosphate columnar aromatic hydrocarbon aqueous phase artificial light harvesting system, preparation method and application

Abstract

The application belongs to the technical field of supramolecular artificial light harvesting system luminescent material, and discloses a phosphate pillar arene water phase artificial light harvesting system, a preparation method and application. The application uses phosphate modified pillar [5] arene compound WPP5 as a host molecule, uses a phenylcarbazolyl modified acrylonitrile derivative compound TPA as a guest molecule and an energy donor, uses a fluorescent dye eosin Y as an energy acceptor, and constructs an efficient water phase artificial light harvesting system in water through host-guest interaction. The light harvesting system prepared by the application can still maintain excellent energy transfer efficiency and antenna effect under a high donor-acceptor ratio, is simple to prepare, low in cost, environmentally friendly, stable in structure, long in storage time, and has potential application value in the field of artificial light harvesting.

Description

Technical Field

[0001] This invention belongs to the field of luminescent materials technology of supramolecular artificial light-harvesting systems, and relates to a phosphate columnar aromatic aqueous phase artificial light-harvesting system, its preparation method and application. Background Technology

[0002] Photosynthesis is one of the most important life activities in nature. Through a light-harvesting system, it effectively captures solar energy and converts it into chemical energy. The natural light-harvesting system in chloroplasts is composed of a large number of orderly arranged antenna pigments. After photons are absorbed by the pigment molecules (donors), the captured energy is transported to the acceptor in the reaction center for catalytic reactions. There, green plants can use CO2 and H2O to synthesize various organic compounds and release O2, which provides important inspiration for researchers to develop artificial light-harvesting systems.

[0003] Fluorescence resonance energy transfer (FRET) is a non-radiative energy transfer mechanism that utilizes long-range dipole-dipole interactions between donor and acceptor pairs to create artificial light-harvesting systems. In recent years, extensive and in-depth research has been conducted on artificial light-harvesting systems that simulate natural processes to further understand natural light-harvesting processes and construct efficient artificial light-harvesting systems. To significantly improve energy conversion efficiency while simulating natural light-harvesting processes, the following basic points should be prioritized: First, the donor and acceptor must be spatially ordered and appropriately spaced (generally within 10 nm); second, the energy donor and acceptor must have good spectral overlap to minimize energy loss during energy transfer; and finally, the donor-acceptor ratio should be relatively high to achieve a robust many-to-one energy supply model. However, due to the inherent hydrophobic effect in aqueous solutions and the aggregation-induced quenching effect of traditional chromophores, most reported artificial light-harvesting systems are constructed in organic phases, severely limiting their application in simulating natural processes. Therefore, constructing efficient artificial light-harvesting systems in aqueous phases is of significant importance and application value. Summary of the Invention

[0004] To address the aforementioned technical issues, this invention provides a phosphate columnar aromatic aqueous artificial light-harvesting system, its preparation method, and its applications.

[0005] To achieve the above objectives, the present invention will adopt the following technical solution:

[0006] In a first aspect, the present invention provides a phosphate-based aromatic hydrocarbon aqueous artificial light-harvesting system, wherein the aqueous artificial light-harvesting system uses compound WPP5 as the host molecule, TPA as the guest molecule and energy donor (D), and a fluorescent dye as the energy acceptor (A); the compound WPP5 and compound TPA form nanoparticles in water through host-guest interactions, and then the fluorescent dye is added, thereby forming an aqueous artificial light-harvesting system by encapsulating the fluorescent dye in the nanoparticles;

[0007] The chemical structural formula of compound WPP5 is shown in formula (I):

[0008]

[0009] The chemical structural formula of compound TPA is shown in formula (II):

[0010]

[0011] The fluorescent dye is eosin Y, and its chemical structural formula is shown in formula (III):

[0012]

[0013] In some specific embodiments, in the above-mentioned aqueous artificial light-harvesting system, the molar ratio of compound TPA to fluorescent dye is (200-2000):1, for example 2000:1, 1000:1, 500:1, 350:1, 250:1, 200:1 or any ratio therebetween.

[0014] In some specific embodiments, the concentration of compound TPA in the above-described aqueous artificial light-harvesting system is 1 × 10⁻⁶. -5 ~1×10 -4 mol / L; the concentration of compound WPP5 is 5 × 10⁻⁶ mol / L. -7 ~4×10 -4 mol / L; the concentration of the fluorescent dye is 5 × 10⁻⁶. -9 ~1×10 -6 mol / L.

[0015] Secondly, the present invention provides a method for preparing the above-mentioned aqueous artificial light-harvesting system, comprising the following steps:

[0016] Step 1: Dissolve compound WPP5, compound TPA, and fluorescent dye in a solvent to prepare a mother liquor;

[0017] Step 2: Add the above mother liquor to water, mix and shake to form a uniformly dispersed nanoparticle solution, and then perform ultrasonic dispersion to obtain an aqueous artificial light-harvesting system.

[0018] Preferably, the solvent for preparing the mother liquor is one of dimethyl sulfoxide, ethanol, N,N-dimethylformamide, and water.

[0019] Thirdly, the present invention provides the application of the above-mentioned light-harvesting system in the preparation of luminescent materials.

[0020] Furthermore, the luminescent material is a photoluminescent material with an excitation wavelength of 275–400 nm.

[0021] Furthermore, the luminescent material is a color-tunable luminescent material.

[0022] In the technical solution of this invention, under excitation light of 275–400 nm, the molar ratio of the energy donor compound TPA to the energy acceptor fluorescent dye is (200–2000):1. Furthermore, the luminescent material exhibits a fluorescence characteristic that changes from cyan to green as the proportion of the fluorescent dye increases, indicating that the dye acceptor is encapsulated within the nanoparticles formed by the host and guest. Tyndall effect and dynamic light scattering experiments confirm that both the system and the system can self-assemble into nanoparticles in aqueous solution before and after the addition of the energy acceptor fluorescent dye, with particle sizes of 114 nm and 115 nm, respectively.

[0023] The light-harvesting system prepared by the technical solution of the present invention effectively overlaps the fluorescence emission region of the energy donor with the ultraviolet absorption region of the fluorescent dye. Through the fluorescence resonance energy transfer process, the energy is efficiently transferred from the donor compound TPA to the fluorescent acceptor, with an energy transfer efficiency of 72%, an antenna effect of 36, and an absolute fluorescence quantum yield increased from 23.09% to 29.70%.

[0024] In the technical solution of this invention, the 380nm excitation wavelength is the maximum absorption wavelength of the energy donor TPA. Under excitation light outside 275-400nm, the energy donor cannot absorb sufficient energy and cannot transfer energy.

[0025] Compared with the prior art, this invention uses phosphate-modified columnar aromatic compound WPP5[5] as the host molecule, phenylcarbazole-modified acrylonitrile derivative compound TPA as the guest molecule and energy donor, and fluorescent dye as the energy acceptor; compound WPP5 and compound TPA self-assemble in water to form nanoparticles through supramolecular host-guest interactions, and then add fluorescent dye to form an artificial light-harvesting system. It has the following advantages:

[0026] (1) In the light-harvesting system provided by the present invention, compound TPA contains an aggregation-induced emission (AIE) active group, acrylonitrile group, which can not only act as a guest molecule to combine with the host compound WPP5 to form an amphiphile, but also act as an energy donor to play a dual role. Due to the AIE characteristics of TPA, the fluorescence of compound TPA is significantly enhanced in the presence of host compound WPP5. Compound WPP5 is a water-soluble columnar aromatic hydrocarbon. In the light-harvesting system, it can form a complex with compound TPA through host-guest interaction and induce compound TPA to further self-assemble in water to form nanoparticles. While significantly improving the fluorescence intensity of compound TPA, it provides a hydrophobic cavity to encapsulate dye molecules to form a light-harvesting system.

[0027] (2) The light-harvesting system provided by the present invention is a water-dispersible nanoparticle constructed in water through host-guest interaction, which has the advantages of fewer synthesis steps, low cost and environmental friendliness;

[0028] (3) The light-harvesting system provided by the present invention has the advantage of structural stability and retains high-efficiency light-emitting characteristics even after long-term storage for several months.

[0029] (4) The fluorescence color of the light-harvesting system provided by the present invention is adjustable. As the proportion of fluorescent dye increases, the fluorescence color changes from cyan fluorescence to green fluorescence, providing a reference for the preparation of new luminescent materials. Attached Figure Description

[0030] Figure 1 The ultraviolet spectrum of compound TPA in Example 1;

[0031] Figure 2 The energy transfer fluorescence spectrum is shown in Example 3;

[0032] Figure 3 The diagram shows the Tyndall effect and particle size distribution in Example 3;

[0033] Figure 4 This is the normalized ultraviolet absorption and fluorescence emission diagram from Example 3;

[0034] Figure 5 This is a graph showing the energy transfer efficiency in Example 3;

[0035] Figure 6 This is an antenna effect diagram from Example 3;

[0036] Figure 7 The absolute fluorescence quantum yield diagram is shown in Example 3;

[0037] Figure 8 This is a fluorescence color transition diagram from Example 3;

[0038] Figure 9 This is the color gamut diagram of the fluorescence color transition in Example 3;

[0039] Figure 10 The hydrogen nuclear magnetic resonance spectrum of compound TPA in Example 1;

[0040] Figure 11 The image shows the carbon NMR spectrum of compound TPA from Example 1. Specific implementation methods

[0041] 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.

[0042] 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.

[0043] Example 1

[0044] Preparation of host compound WPP5:

[0045] In this embodiment, compound WPP5 was synthesized according to the literature J. Colloid Interface Sci., 2023, 641, 803-811, and its structure is shown below:

[0046]

[0047] Preparation of guest compound TPA:

[0048] In this embodiment, compound TPA is synthesized from compound A as a starting material. The structural formula of compound A is as follows:

[0049]

[0050] Compound A (200 mg, 0.56 mmol), 4-(9H-carbazole-9-yl)benzaldehyde (156 mg, 0.56 mmol), and tetrabutylammonium hydroxide (8 drops) were added to 25 mL of ethanol and stirred overnight at room temperature. The product was allowed to stand, filtered, and the filter cake was collected. It was then washed with ethanol (60 mL in total) and finally dried under vacuum to give compound B (304 mg, 0.50 mmol).

[0051] The structural formula of compound B is as follows:

[0052]

[0053] Compound B (200 mg, 0.34 mmol) and trimethylamine (196 mg, 3.4 mmol) were added to 30 mL of ethyl acetate and stirred overnight at room temperature. After standing and filtration, the solid product was collected, washed with anhydrous diethyl ether (total 100 mL), and dried under vacuum to give compound TPA (214 mg, 0.32 mmol).

[0054] The proton NMR spectrum of compound TPA is as follows: Figure 10 As shown: 1 H NMR (DMSO-d6, 400MHz, 298K) δ (ppm): 8.29 (dd, J=22, 8Hz, 4H), 8.08 (s, 1H), 7.93–7.66 (m, 5H), 7.50–7.46 (m, 3H), 7.38–7.3 2(m,2H),7.11–7.05(m,2H),4.06(t,J=6.4Hz,2H),3.30–3.26(m,2H),3.05(s,9H),1.76–1.65(m,4H),1.43–1.31(m,12H).

[0055] The carbon NMR spectrum of compound TPA is as follows: Figure 11 As shown: 13 C NMR(DMSO-d6,100MHz,298K)δ(ppm):160.1,140.1,139.8,138.7,133.3,131.2,129.5,127.8,127.4,127.2,126.9, 126.4,123.5,121.1,121.0,118.6,115.6,110.6,110.3,68.2,65.7,52.6,29.4,29.2,29.1,29.0,26.2,26.0,22.5.

[0056] The structure of compound TPA was determined through the above experimental characterization as follows:

[0057]

[0058] like Figure 1 As shown, through ultraviolet spectroscopy testing, the ultraviolet absorption of compound TPA is mainly in the 275-400nm region, so the excitation wavelength range can be selected as 275-400nm.

[0059] Example 2

[0060] Preparation of supramolecular nanoparticles:

[0061] Step 1: Weigh 5g of compound WPP from Example 1 into a 100mL volumetric flask, add ultrapure water to bring the volume to 100mL, and prepare a 4.2×10⁻⁶ ppm solution.-4 mol / L mother liquor;

[0062] Step 2: Weigh the compound TPA from Example 1 into a 2 mL volumetric flask, add dimethyl sulfoxide and bring the volume to 2 mL to prepare a 2×10⁻⁶ volumetric flask. -2 mol / L mother liquor;

[0063] Step 3: Transfer 4 mL of ultrapure water to a 5 mL volumetric flask using a pipette. Then, add appropriate amounts of the WPP5 and TPA mother solutions to the volumetric flask according to the ratio. Add ultrapure water to bring the volume to 5 mL and sonicate for 5 min to form aqueously dispersed WPP5-TPA nanoparticles with a particle size of 114 nm. Figure 3 );

[0064] In this embodiment, the ultrasonic instrument used is a commonly used laboratory ultrasonic cleaner with a frequency of 40kHz.

[0065] The fluorescence of the above-mentioned aqueous-dispersed nanoparticles was measured using a fluorescence spectrophotometer with an excitation wavelength of 365 nm. The corresponding fluorescence spectrum is shown below. Figure 2 As shown in the figure, the fluorescence emission peak of compound TPA is at 490 nm.

[0066] Example 3

[0067] Preparation of light-harvesting systems:

[0068] In this embodiment, the fluorescent dye eosin Y is preferably used as the energy acceptor (A), and the compound TPA is used as the energy donor (D).

[0069] Step 1: Weigh the fluorescent dye Eosin Y into a 5 mL volumetric flask, add dimethyl sulfoxide and dilute to 5 mL to prepare a 2×10⁻⁶ solution. -4 mol / L mother liquor;

[0070] Step 2: Transfer 4 mL of ultrapure water to a 5 mL volumetric flask using a pipette. Then, transfer appropriate amounts of the mother liquor of compound TPA, the mother liquor of compound WPP5, and the mother liquor of the fluorescent dye to the same volumetric flask according to the specified ratio. Add ultrapure water to bring the volume to 5 mL and sonicate for 5 min to form aqueously dispersed nanoparticles WPP5-TPA-A with a particle size of 115 nm. Figure 3 The concentration of compound TPA was 5 × 10⁻⁶. -5 The concentration of compound WPP5 is 2.5 × 10 mol / L. -6 The corresponding donor-acceptor ratios were 200:1, 250:1, 350:1, 500:1, 1000:1, and 2000:1, respectively.

[0071] The fluorescence intensity of the above samples was measured using fluorescence spectroscopy with an excitation wavelength of 365 nm. The corresponding fluorescence spectra are shown below. Figure 2 As shown.

[0072] like Figure 4 As shown, due to the high overlap between the fluorescence emission region of TPA and the ultraviolet absorption region of eosin Y, efficient energy transfer processes can occur in WPP5-TPA-A nanoparticles.

[0073] like Figure 2 As shown, the fluorescence intensity of the characteristic emission peak (490 nm) of TPA, the energy donor, gradually decreases with increasing energy acceptor concentration; while the fluorescence intensity of the characteristic emission peak (550 nm) of eosin Y, the energy acceptor, gradually increases with increasing energy acceptor concentration, indicating excellent energy transfer efficiency and artificial light trapping capability. The energy transfer efficiency reaches 72% ( Figure 5 The antenna effect reaches 36 ( Figure 6 The absolute fluorescence quantum yield increased from 23.09% to 29.70%. Figure 7 ).

[0074] The above energy transfer efficiency (Φ) ET The fluorescence spectrum was calculated using formula S1:

[0075] Φ ET =1-I DA / I D (eq.S1)

[0076] Among them, I DA and I D These are the fluorescence intensities of WPP5-TPA-A and WPP5-TPA at 490 nm when excited at 365 nm, respectively. Figure 5 ).

[0077] The antenna effect (AE) above is calculated from the fluorescence spectrum using formula S2:

[0078] AE = (I DA,365 –I D,365 ) / I DA,500 (eq.S2)

[0079] Among them, I DA,365 and I DA,500 These are the fluorescence intensities of WPP5-TPA-A at 550 nm under excitation at 365 nm and 500 nm, respectively; I D,365 The normalized calculation of WPP5-TPA at 490 nm shows the fluorescence intensity at 550 nm. Figure 6 ).

[0080] Furthermore, observations under ultraviolet light revealed that as the concentration of the dye acceptor eosin Y increased, the fluorescence color gradually shifted towards green. Figure 8 and Figure 9 ).

[0081] The basic principles and main features of the present invention have been described above. It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or basic characteristics. Therefore, the embodiments should be considered exemplary and non-limiting in all respects. The scope of the invention is defined by the appended claims rather than the foregoing description, and thus all variations falling within the meaning and scope of the equivalents of the claims are intended to be included within the present invention. Although embodiments of the invention have been described, it will be understood by those skilled in the art that various changes, modifications, substitutions, and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A phosphate pillar arene-based aqueous phase artificial light-harvesting system, characterized in that, The aqueous artificial light-harvesting system uses compound WPP5 as the host molecule, compound TPA as the guest molecule and energy donor, and fluorescent dye as the energy acceptor. The aqueous artificial light-harvesting system is formed by encapsulating the fluorescent dye in nanoparticles formed by the host-guest interaction of the compound WPP5 and the compound TPA in water. The chemical structural formula of compound WPP5 is shown below: ； The chemical structural formula of compound TPA is shown below: ； The fluorescent dye is eosin Y, and its chemical structural formula is shown below: ； The molar ratio of the compound TPA to the fluorescent dye is (200-2000):

1.

2. A process for the preparation of an aqueous phase artificial light-harvesting system according to claim 1, characterized in that, Includes the following steps: S1. Dissolve compound WPP5, compound TPA, and fluorescent dye in a solvent to prepare a mother liquor; S2. Add the mother liquor to water, mix and shake to form a uniformly dispersed nanoparticle solution, and then perform ultrasonic dispersion to obtain the artificial light-harvesting system.

3. The preparation method according to claim 2, characterized in that, In step S1, the solvent is one of dimethyl sulfoxide, ethanol, N,N-dimethylformamide, and water.

4. The application of the aqueous artificial light-harvesting system according to claim 1 in the preparation of luminescent materials.

5. Use according to claim 4, characterized in that, The luminescent material is a photoluminescent material with an excitation wavelength of 275–400 nm.

6. Use according to claim 4, characterized in that, The luminescent material is a color-tunable luminescent material, with a color range from cyan to green.

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