Preparation and application of D-pi-A type near-infrared photothermal material based on tricyanofuran as receptor

Abstract

The invention belongs to the field of organic photoelectric materials and biomedical treatment, and discloses preparation and application of a D-pi-A type near-infrared photothermal material based on tricyanofuran as a receptor. Based on an electron withdrawing group tricyanofuran, 3, 4-ethylenedioxythiophene is used as a pi bridge to construct the near-infrared light thermal material with two strong electron donating groups. The D-pi-A type fluorescent molecules have the following structures I and II: an electron withdrawing group tricyanofuran and 3, 4-ethylenedioxythiophene are used as a pi bridge and are connected with a strong electron donating group, and two D-pi-A type fluorescent molecules are designed and synthesized. And the tricyanofuran has very strong electron accepting capability. Three cyano groups in the molecule are strong electron withdrawing groups and can effectively attract electrons. When interacting with an electron donor, the compound can quickly receive electrons to form a stable electron transfer compound. 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 D-π-A type near-infrared photothermal materials by increasing the electron push-pull effect to reduce the bandgap and promote the emission redshift, as well as its application. Background Technology

[0002] Currently, most cancer treatments involve monotherapy with chemotherapy. However, the toxic side effects of chemotherapy on normal tissues and the development of drug resistance in tumors limit its long-term development. To avoid the side effects of chemotherapy and address the challenge of drug resistance in monotherapy, the development of combination therapy modalities for cancer is gradually becoming a new trend in cancer treatment. Combination therapy modalities can produce synergistic or enhanced effects, significantly improving treatment outcomes and, to some extent, preventing toxic side effects on normal tissues and the problem of drug resistance in tumors. Photothermal therapy is a photothermal conversion process that generates heat, thereby inducing local thermal damage. Compared to the limited tissue penetration and higher phototoxicity of ultraviolet and visible light, infrared light offers deeper tissue penetration and minimal side effects.

[0003] Tricyanofuran (TCF) has broad application prospects in fields such as fluorescent probes, photosensitizers, antibacterial materials, and chemical synthesis due to its strong electron-withdrawing ability and unique chemical properties. In the photothermal field, TCF applications mainly focus on the development of photothermal conversion materials. Its strong electron-withdrawing ability and good photothermal performance demonstrate its broad application potential in photothermal catalysis, photothermal therapy, seawater desalination, and antibacterial applications.

[0004] TCF derivatives have important applications in photothermal therapy. For example, TIDT, a novel photosensitizer based on tricyanofuran, exhibits highly efficient photothermal conversion performance and photostability through an ADA-type molecular structure design. This material demonstrates 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. Near-infrared materials mainly involve constructing DA structures, which can undergo electronic push-pull effects, leading to strong charge transfer within molecules with DA configurations. This intramolecular charge transfer (ICT) is beneficial to ΔE. ST The wavelength narrows. For such molecules, stronger D or A is more conducive to enhancing the ICT process, effectively promoting wavelength redshift. Summary of the Invention

[0005] To address the above issues, a method will be designed and synthesized to reduce the band gap of a class of D-π-A near-infrared materials by increasing electron push-pull interactions. Using tricyanofuran as an acceptor, a DA backbone is constructed with electron-donating groups. 3,4-ethylenedioxythiophene is then used to extend the π-conjugation length within the DA molecular backbone. By utilizing mechanisms such as enhanced conjugated chain length and intramolecular charge transfer, near-infrared II photothermal materials can be prepared.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a method for reducing the bandgap of a class of D-π-A near-infrared materials by increasing electron push-pull interaction, the preparation method of which includes the following steps:

[0007] In a nitrogen atmosphere, 3,4-ethylenedioxythiophene aldehyde containing triphenylamine derivatives or tetraphenylethylene derivatives 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 the 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.

[0008] The structure is as follows:

[0009]

[0010] Beneficial effects of this invention:

[0011] 1. This invention synthesizes a class of near-infrared II materials by introducing 3,4-ethylenedioxythiophene into a DA framework that enhances electron-withdrawing ability, thereby increasing its electron push-pull effect. Near-infrared materials are prepared by utilizing mechanisms such as enhanced conjugated chain length and intramolecular charge transfer. These materials also exhibit good photothermal effects.

[0012] 2. The near-infrared material provided by the present invention introduces 3,4-ethylenedioxythiophene into the DA framework. On the one hand, the thiophene derivative can extend the π conjugation length, and thiophene and its derivatives can act as electron donors to further increase ICT and effectively promote wavelength redshift. On the other hand, it constructs a D-π-A type near-infrared photothermal material with tricyanofuran.

[0013] 3. The method for synthesizing the D-π-A type near-infrared material provided by this invention is simple and the raw materials are readily available.

[0014] 4. The near-infrared material provided by this invention has an emission wavelength of 972 nm and a tail extending into the near-infrared II region. Attached Figure Description

[0015] Figure 1 A and B are the absorption spectra of TCF-ETT and TCF-ETTPE, respectively;

[0016] Figure 2 A and B are the emission spectra of TCF-ETT and TCF-ETTPE, respectively;

[0017] Figure 3 A and B are the photothermal conversion measurement graphs of TCF-ETT and TCF-ETTPE at different powers, respectively; C and D are the photothermal conversion measurement graphs of TCF-ETT and TCF-ETTPE at different concentrations, respectively.

[0018] Figure 4 TCF-ETTPE NMR spectrum; Detailed Implementation

[0019] 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.

[0020] Example 1:

[0021] Preparation of TCF-ETT:

[0022]

[0023] Synthetic route of TCF-ETT

[0024] Synthesis of TCF-ETT: Under a nitrogen atmosphere, 5-bromo-2-(3,4-vinyldioxythiophene)carboxaldehyde (0.20 g, 0.8 mmol), compound 10 (0.85 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 20 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 (0.4 g, yield 67%). 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 was refluxed at C for 4 h. The reaction solution was post-treated (concentrated, column chromatography, methanol crystallization) and filtered to collect a dark black solid (0.05 g, yield 20%).

[0025] The structural characterization data of the obtained 10 are shown below:

[0026] 1 H NMR (500 MHz, DMSO), δ (ppm): 7.53 (d, J = 8.4 Hz, 2H), 7.29 (t, J= 7.9 Hz, 8H), 7.03-6.91 (m, 22H), 1.26 (s, 12H).

[0027] Example 2:

[0028] Preparation of TCF-ETTPE:

[0029]

[0030] Synthetic route of TCF-ETTPE

[0031] Synthesis of TCF-ETTPE: Under a nitrogen atmosphere, 5-bromo-2-(3,4-vinyldioxythiophene)carboxaldehyde (0.20 g, 0.8 mmol), compound 17 (1.1 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 20 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 cooling to room temperature, the solvent was evaporated under reduced pressure, and the residue was purified by silica gel column chromatography. A solid was obtained in 86% yield (0.64 g). 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 reacted 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 filtered to collect a dark black solid (0.08 g, 40% yield). The NMR structure is shown below. Figure 4 As shown.

[0032] The structural characterization data of the obtained product are shown below:

[0033] 1 H NMR (500 MHz, CDCl3) δ 7.69 (dd, J = 59.0, 12.1 Hz, 3H), 7.20–6.76(m, 41H), 4.47–4.32 (m, 4H), 1.87 (s, 6H).

[0034] Example 3:

[0035] Absorption spectral characterization of near-infrared materials TCF-ETT and TCF-ETTPE

[0036] Figure 1 A and Figure 1 B shows the absorption spectra of TCF-ETT and TCF-ETTPE obtained in Examples 1 and 2 in THF. The maximum absorption spectrum of TCF-ETT in THF solution is 640 nm, while the maximum absorption wavelength of TCF-ETTPE is 615 nm.

[0037] Example 4:

[0038] Emission spectral characterization of TCF-ETT and TCF-ETTPE

[0039] Figure 2 The emission spectra of TCF-ETT and TCF-ETTPE obtained in Examples 1 and 2 in THF at room temperature are shown. Figure 2 A represents the emission spectrum of TCF-ETT in THF at room temperature. Figure 2 B is the emission spectrum of TCF-ETTPE. The maximum emission spectrum of TCF-ETT in THF solution is 972 nm, while the maximum absorption wavelength of TCF-ETTPE is 923 nm.

[0040] Example 5:

[0041] Figure 3 The graphs show the photothermal conversion of TCF-ETT and TCF-ETTPE, demonstrating their excellent photothermal conversion efficiency due to good non-radiative transitions.

[0042] Example 6

[0043] Attached diagrams for TCF-ETT and TCF-ETTPE.

Claims

1. Preparation and application of a class of D-π-A type near-infrared photothermal materials based on tricyanofuran as the acceptor, characterized by the following molecular features: 。 2. The preparation and application of a type D-π-A near-infrared photothermal material based on tricyanofuran as the acceptor according to claim 1, characterized in that: When tricyanofuran is used as an acceptor and attached to an electron-rich donor (D), an electron push-pull effect occurs, leading to a strong charge transfer within the DA-configured molecule; this intramolecular charge transfer (ICT) favors ΔE. ST The narrowing of the wavelength; for such molecules, stronger D or A is more conducive to enhancing the ICT process and effectively promoting wavelength redshift.

3. The preparation and application of the D-π-A type near-infrared photothermal material based on tricyanofuran as the acceptor as described in claim 1, characterized in that: By using tricyanofuran as an acceptor and constructing a DA backbone with a strong electron-donating group, the electron push-pull effect is increased to reduce the molecular band gap, thereby resulting in a material with redshifted absorption and emission. Furthermore, the introduction of thiophene derivatives into the DA backbone further increases the conjugation degree to reduce the band gap. Structure I has an emission peak of 972 nm in tetrahydrofuran (THF) solution, with its tail entering the near-infrared II region, which has potential applications in the field of fluorescence imaging.

4. The preparation and application of a type D-π-A near-infrared photothermal material based on tricyanofuran as the acceptor according to claim 1, characterized in that: By using tricyanofuran as an electron-withdrawing group and 3,4-ethylenedioxythiophene (EDOT) as a π-bridge, near-infrared photothermal materials can be prepared through mechanisms such as enhanced conjugated chain length and intramolecular charge transfer.

5. The preparation and application of a type D-π-A near-infrared photothermal material based on tricyanofuran as the acceptor according to claim 1, characterized in that: Using tricyanofuran as the acceptor, a strong electron donor is selected and an intramolecular charge transfer (ICT) mechanism is introduced. By designing intramolecular rotation, the formation of the ICT state is promoted, thereby achieving redshift emission and obtaining near-infrared stimulated photothermal materials.

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