Preparation method and application of near-infrared luminescent material based on tricyanofuran as receptor

Abstract

The invention discloses a preparation method and application of a near-infrared luminescent material based on tricyanofuran as a receptor, and the near-infrared luminescent material is constructed by constructing different donor units based on tricyanofuran. According to the D-pi-A type near-infrared molecules, tricyanofuran is used as an electron withdrawing group, 3, 4-ethylenedioxythiophene (EDOT) is used as a pi bridge to increase the conjugation degree, and the D-pi-A type near-infrared molecules are connected with various donors to design and synthesize two D-pi-A type near-infrared molecules. Nitrogen atoms and oxygen atoms in tricyanofuran molecules have high electronegativity and can attract electrons, so that the whole molecules have high electron acceptance. The furan ring in the molecular structure has aromaticity, and can generate pi-pi interaction with a donor molecule with aromaticity. The interaction can enhance the binding capacity between the acceptor and the donor, further promote transfer and transfer of electrons, and improve the efficiency and selectivity of the reaction. A thought is provided for the design of the molecules.

Description

Technical Field

[0001] This invention belongs to the field of organic optoelectronic materials and their biomedical applications, and specifically relates to a method for preparing a class of near-infrared luminescent materials by using tricyanofuran as an acceptor to induce a redshift in emission, and its application. Background Technology

[0002] Tricyanofuran (TCF), due to its strong electron-withdrawing ability and unique chemical properties, has broad application prospects in fields such as fluorescent probes, photosensitizers, antibacterial materials, and chemical synthesis. Its research and application in biomedical imaging, photodynamic therapy, and photothermal fields have received particular attention. The application of TCF in the photothermal field mainly focuses on the development of photothermal conversion materials. Its strong electron-withdrawing ability and good photothermal performance make it show broad application prospects in photothermal catalysis, photothermal therapy, seawater desalination, and antibacterial applications. TCF derivatives have important applications in photothermal therapy.

[0003] Studies have shown that increasing the conjugate length helps to shorten ΔE. ST Common methods include adding methylene fragments or introducing thiophene as a π-bridge. In constructing near-infrared luminescent materials, the main method for extending the wavelength is the introduction of thiophene. Furthermore, the heteroatomic sulfur in thiophene can promote intermolecular and intramolecular interactions in aggregated states, utilizing the RIM effect to harden molecular conformations and enhance fluorescence. A novel photosensitizer, TIDT, based on tricyanofuranium, exhibits highly efficient photothermal conversion performance and photostable stability through ADA-type molecular structure design. This material shows significant fluorescence and photoacoustic imaging capabilities in the NIR-II region and can be used for photothermal therapy of tumors in vivo. Moreover, the heat generated by the photothermal effect can effectively kill bacteria while reducing damage to normal tissues. Summary of the Invention

[0004] To address the above issues, a method for synthesizing a class of near-infrared luminescent materials using tricyanofuran as an acceptor will be designed. Based on tricyanofuran as the acceptor, 3,4-ethylenedioxythiophene will be used to introduce and extend the π-conjugation length, promoting the formation of molecular coplanarity. This will lead to stronger intermolecular π-π interactions and induce a more delocalized highest occupied molecular orbital (HOMO) distribution along the backbone, which will enhance intramolecular charge transfer (ICT) and achieve a redshift. The basic application of photothermal therapy will be realized by measuring the photothermal properties.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a method for preparing a class of near-infrared luminescent materials using tricyanofuran as an acceptor, the preparation method comprising the following steps:

[0006] In a nitrogen atmosphere, 3,4-ethylenedioxythiophene aldehyde containing triphenylamine or tetraphenylethylene and 2-(3-cyano-4,5,5-trimethylfuran-2(5H)-ethyl)malonitrile were added to the reactor at a molar ratio of 1:1.5. Chloroform was added as a solvent, and pyridine was used as a catalyst. The mixture was stirred with a magnetic stirrer until dissolved. 70 o The reaction was carried out at C for 4 h. After the reaction was completed, the solvent was removed by vacuum distillation to obtain the crude product, which was then purified by column chromatography to obtain the target compound.

[0007] The structure is:

[0008]

[0009] Beneficial effects of this invention:

[0010] 1. This invention synthesizes a class of near-infrared luminescent materials. By using tricyanofuran as an acceptor and triphenylamine and tetraphenylethylene as donors to construct a DA structure, 3,4-ethylenedioxythiophene is introduced into the DA backbone to increase its conjugation length. The near-infrared luminescent materials are prepared by utilizing mechanisms such as enhanced conjugation chain length and intramolecular charge transfer.

[0011] 2. The near-infrared luminescent material provided by this invention uses tricyanofuran as the acceptor and introduces 3,4-ethylenedioxythiophene into the DA backbone. On the one hand, the strong electron-withdrawing ability and good photothermal properties of tricyanofuran make it show broad application prospects in photothermal catalysis, photothermal therapy, seawater desalination and antibacterial fields. On the other hand, the thiophene derivative can extend the π-conjugation length and promote the formation of molecular coplanarity, which will lead to stronger intermolecular π-π interactions and induce a more delocalized highest occupied molecular orbital (HOMO) distribution along the backbone. This will enhance intramolecular charge transfer (ICT) and achieve redshift.

[0012] 3. The synthesis of the D-π-A type near-infrared luminescent material provided by this invention has few steps, is simple, and uses readily available raw materials.

[0013] 4. The near-infrared luminescent material provided by this invention has an emission wavelength of 895 nm and is a near-infrared region I material. Attached Figure Description

[0014] Figure 1 The absorption spectra of TCF-ET and TCF-ETPE in THF;

[0015] Figure 2 Emission spectra of TCF-ET and TCF-ETPE;

[0016] Figure 3 The NMR spectrum of compound 3 is shown below.

[0017] Figure 4TCF-ETPE NMR spectrum; Detailed Implementation

[0018] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings, so that those skilled in the art can better understand the advantages and features of the present invention, thereby making a clearer definition of the scope of protection of the present invention. The embodiments described in this invention are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0019] Example 1:

[0020] Preparation of TCF-ET:

[0021]

[0022] Synthetic route of TCF-ET

[0023] Synthesis of TCF-ET: Under a nitrogen atmosphere, 5-bromo-2-(3,4-vinyldioxythiophene)carboxaldehyde (0.20 g, mmol), triphenylamine 4-borate (0.6 g, 1.2 mmol), tetrakis(triphenylphosphine)palladium (0.05 g, 0.04 mmol), and potassium carbonate (0.2 g, 1.2 mmol) were added to 30 mL of a mixed solvent of toluene, ethanol, and water in an 8:1:1 ratio. The reaction was carried out at 90 °C for 12 h. After the reaction was completed, the system was cooled, concentrated under reduced pressure, and separated by silica gel column chromatography to obtain a yellow solid product (0.2 g, 60% yield). 0.2 g of the above product was dissolved in ethanol / THF with 2-(3-cyano-4,5,5-trimethylfuran-2(5H)-methylene)malonium (0.105 g, 0.45 mmol), and a few drops of pyridine were added as a catalyst. The mixture was then subjected to a reaction at 70 °C. o The reaction mixture was refluxed at C for 4 h. After post-treatment (concentration, column chromatography, methanol crystallization), the solution was collected by filtration to obtain a dark black solid (0.05 g, yield 41%). The NMR structure of compound 3 is shown below. Figure 3 As shown.

[0024] The structural characterization data of compound 3 are shown below:

[0025] 1H NMR (500 MHz, CDCl3) δ 9.90 (s, 1H), 7.64 (d, J = 8.4 Hz, 2H), 7.29 (d, J = 7.7 Hz, 4H), 7.14–7.03 (m, 8H), 4.38 (d, J = 16.2 Hz, 4H).

[0026] Example 2:

[0027] Preparation of TCF-ETPE:

[0028]

[0029] Synthetic route of TCF-ETPE

[0030] Synthesis of TCF-ETPE: Under a nitrogen atmosphere, 5-bromo-2-(3,4-vinyldioxythiophene)carboxaldehyde (0.20 g, 0.8 mmol), 1-(4-phenylboronic acid pinacol ester)-1,2,2-tristyrene (0.55 g, 1.2 mmol), tetrakis(triphenylphosphine)palladium (0.05 g, 0.04 mmol), and potassium carbonate (0.2 g, 1.2 mmol) were added to 30 mL of a mixed solvent of toluene, ethanol, and water in an 8:1:1 ratio. The reaction was carried out at 90 °C for 12 h. After the reaction was completed, the system was cooled, concentrated under reduced pressure, and separated by silica gel column chromatography to obtain a yellow solid product (0.25 g, yield 63%). Take 0.2 g of the above product and dissolve it with 0.105 g (0.45 mmol) of 2-(3-cyano-4,5,5-trimethylfuran-2(5H)-methylene)malonium in ethanol / THF, add a few drops of pyridine as a catalyst, and 70 o The reaction mixture was refluxed at C for 4 h. After post-treatment (concentration, column chromatography, methanol crystallization), the solution was filtered to collect a dark black solid (0.05 g, yield 35%). The NMR structure is shown below. Figure 4 As shown.

[0031] The structural characterization data of the obtained product are shown below:

[0032] 1 H NMR (500 MHz, CDCl3) δ 7.75 (d, J = 15.7 Hz, 1H), 7.57 (d, J = 8.1Hz, 2H), 7.23–6.95 (m, 17H), 6.63 (d, J = 15.7 Hz, 1H), 4.44 (s, 1H), 4.47–4.32 (m, 4H), 1.77 (s, 6H).

[0033] Example 3:

[0034] Absorption spectral characterization of near-infrared luminescent materials TCF-ET and TCF-ETPE

[0035] Figure 1 A and Figure 1 B shows the absorption spectra of TCF-ET and TCF-ETPE obtained in Examples 1 and 2 in THF. The maximum absorption spectrum of TCF-ET in THF solution is 600 nm, while the maximum absorption wavelength of TCF-ETPE is 540 nm.

[0036] Example 4:

[0037] Emission spectral characterization of TCF-ET and TCF-ETPE

[0038] Figure 2 The emission spectra of TCF-ET and TCF-ETPE obtained in Examples 1 and 2 in THF at room temperature are shown. Figure 2 A represents the emission spectrum of TCF-ET in THF at room temperature. Figure 2 B is the emission spectrum of TCF-ETPE. The maximum emission spectrum of TCF-ET in THF solution is 895 nm, while the maximum absorption wavelength of TCF-ETPE is 662 nm.

[0039] Example 5

[0040] Attached diagrams for TCF-ET and TCF-ETPE.

Claims

1. A method for preparing near-infrared luminescent materials based on tricyanofuran as the acceptor and their applications, characterized by the following molecular features: 。 2. The preparation and application of the near-infrared luminescent material based on tricyanofuran as the acceptor according to claim 1, characterized in that: Using tricyanofuran as the acceptor and triphenylamine and tetraphenylethylene as donors, a DA backbone was constructed. 3,4-ethylenedioxythiophene was introduced into the DA backbone as a π-bridge to further increase the conjugation degree and reduce the band gap, thereby further redshifting the emission.

3. The preparation and application of the near-infrared luminescent material based on tricyanofuran as the acceptor according to claim 1, characterized in that: Near-infrared luminescent materials using tricyanofuran as the acceptor, structure I, exhibits an emission peak of 895 nm in tetrahydrofuran (THF) solution, clearly entering the near-infrared I region, and has potential applications in the field of fluorescence imaging.

4. The preparation and application of the near-infrared luminescent material based on tricyanofuran as the acceptor according to claim 1, characterized in that: Near-infrared luminescent materials were prepared by using 3,4-ethylenedioxythiophene as a π-bridge and tricyanofuran as an acceptor, and by utilizing mechanisms such as enhanced conjugated chain length and intramolecular charge transfer.

5. The preparation and application of the near-infrared luminescent material based on tricyanofuran as the acceptor according to claim 1, characterized in that: The acceptor is tricyanofuran. 3,4-ethylenedioxythiophene is introduced into the DA backbone. On the one hand, the strong electron-withdrawing ability and good photothermal properties of tricyanofuran make it show broad application prospects in photothermal catalysis, photothermal therapy, seawater desalination and antibacterial fields. On the other hand, the thiophene derivative can prolong the π-conjugation length and promote the formation of molecular coplanarity. This will lead to stronger intermolecular π-π interactions and induce a more delocalized highest occupied molecular orbital (HOMO) distribution along the backbone. This will enhance intramolecular charge transfer (ICT) and achieve redshift.

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