Near-infrared two-region luminescent material as well as preparation method and application thereof

Abstract

The invention discloses a near-infrared two-region light-emitting material and a preparation method and application thereof, and belongs to the technical field of organic light-emitting materials, the near-infrared two-region light-emitting material provided by the invention is 2-(4, 8-bis (5-[4-(bis (4-methoxyphenyl) amino) phenyl] thiophene-2-yl)-[1, 3] dithieno [4 ', 5': 4, 5]-[1, 2, 5] benzothiadiazole-6-subunit) malononitrile (TTBSMCN), and the near-infrared two-region light-emitting material is a near-infrared two-region light-emitting material. The TTBSMCN prepared by the preparation method disclosed by the invention realizes high-efficiency luminescence of a near-infrared second region, the emission wavelength can reach more than 1000nm, and the fluorescence quantum yield is higher than that of an existing material; the TTBSMCN shows a remarkable AIE effect in an aggregation state, and the aggregation quenching problem of a traditional material is effectively avoided. The TTBSMCN NPs shows excellent targeting performance and high signal-to-noise ratio in biological imaging, and high-resolution imaging of a tumor area can be realized.

Description

Technical Field

[0001] This invention belongs to the field of organic light-emitting materials technology, and particularly relates to a near-infrared II light-emitting material, its preparation method and application. Background Technology

[0002] Near-infrared II (NIR-II, wavelength range 1000-1700 nm) optical windows have shown great promise in in vivo fluorescence imaging and medical diagnostics due to their advantages such as strong tissue penetration, high imaging resolution, and no ionizing radiation. However, current NIR-II luminescent materials still face significant challenges in molecular design: most existing materials have low luminescence efficiency, making it difficult to meet the requirements of high-sensitivity imaging; most strategies rely on extending / expanding the donor structure to achieve redshifted molecular emission, which has drawbacks such as complex synthesis, cumbersome steps, and high costs; and there is a lack of systematic molecular regulation strategies to adjust the emission wavelength and efficiency.

[0003] In recent years, aggregation-induced emission (AIE) materials have attracted attention due to their significantly enhanced luminescence efficiency in the aggregated state. However, there are few reports on achieving high-efficiency NIR-II luminescence through molecular stacking regulation, highlighting the urgent need to develop novel molecular design strategies to address these issues. Summary of the Invention

[0004] To address the challenges of complex synthesis and difficult-to-tune emission wavelength in existing NIR-II luminescent materials, this invention proposes a near-infrared II luminescent material, its preparation method, and its applications. By modifying the microstructure of the molecular acceptor portion and adjusting the stacking structure of the molecular aggregate, this invention yields a highly efficient near-infrared II luminescent material, improving the aggregated-state luminescence efficiency and providing a new approach for the development of NIR-II materials.

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

[0006] This invention provides a near-infrared II luminescent material, which is 2-(4,8-bis(5-[4-(bis(4-methoxyphenyl)amino)phenyl]thiophen-2-yl)-[1,3]dithiapento[4′,5′:4,5]no[1,2,5]benzothiadiazole-6-ylidene)malonitrile, denoted as TTBSMCN, with the following structural formula:

[0007]

[0008] Based on the D-π-A-π-D molecular structure, this invention designs a novel material compound, 2-(4,8-bis(5-[4-(bis(4-methoxyphenyl)amino)phenyl]thiophen-2-yl)-[1,3]dithiapento[4′,5′:4,5]no[1,2,5]benzothiadiazole-6-ylidene)malonitrile (TTBSMCN). A comparison with compound 2-4,4'-((5,6-difluoro[1,2,5]thiadiazole[c]phenyl-4,7-diyl)bis(thiophen-5,2-diyl))bis[N,N-bis(4-methoxyphenyl)aniline] (TTBSM) shows that this invention optimizes the molecular stacking by extending the acceptor structure and introducing electron-adsorbing groups.

[0009] The present invention also provides a method for preparing the near-infrared II luminescent material, comprising the following steps:

[0010] Step (i): 5,6-Difluoro-4,7-bis(thiophen-2-yl)[1,2,5]thiadiazole was added to anhydrous tetrahydrofuran, cooled to -78°C, and then diisopropyllithium amine was added. The mixture was stirred until homogeneous at this temperature. A tetrahydrofuran solution of trimethyltin chloride was added, and the mixture was stirred at room temperature. After the reaction was completed, a saturated aqueous solution of potassium fluoride (KF) was added to quench the reaction. The reaction solution was extracted with dichloromethane and water. The organic phase was dried over anhydrous sodium sulfate, filtered, and purified by column chromatography to obtain 5,6-difluoro-4,7-bis[5-(trimethyltin)thiophen-2-yl][1,2,5]thiadiazole.

[0011] Step (ii): Under nitrogen protection, 5,6-difluoro-4,7-bis[5-(trimethyltin)thiophen-2-yl][1,2,5]thiadiazole, 4-bromo-N,N-bis(4-methoxyphenyl)aniline, tris(dibenzylacetone)dipalladium(O) and tris(o-methylphenyl)phosphine were added to anhydrous toluene and stirred until homogeneous. The reaction mixture was then heated. After the reaction was complete, the reaction solution was extracted with water and dichloromethane. The organic phase was dried over anhydrous sodium sulfate, filtered, and purified by column chromatography to obtain TTBSM. The structural formula of TTBSM is [insert structural formula here].

[0012] Step (iii): Under nitrogen protection, TTBSM, 2,2-dicyanethylene-1,1-bis(sodium thiolate) and tetrabutylammonium bromide were added to anhydrous N,N-dimethylformamide and stirred until homogeneous. The reaction mixture was then reacted under heating conditions. After the reaction was completed, the solvent was removed under reduced pressure. The residue was extracted with dichloromethane and water (dichloromethane / water). The organic phase was dried with anhydrous sodium sulfate, filtered, purified by column chromatography, and recrystallized with a dichloromethane / n-hexane mixed solvent to obtain the near-infrared II luminescent material.

[0013] Further, in step (i), the molar ratio of 5,6-difluoro-4,7-bis(thiophen-2-yl)[1,2,5]thiadiazole, diisopropyllithium amine, and trimethyltin chloride is 0.74∶2.23∶2.23.

[0014] Further, in step (i), the volume ratio of dichloromethane to water is 1:10;

[0015] And / or, during the column chromatography purification, the eluent is a mixture of dichloromethane and petroleum ether in a volume ratio of 1:5.

[0016] Further, in step (ii), the molar ratio of 5,6-difluoro-4,7-bis[5-(trimethyltin)thiophen-2-yl][1,2,5]thiadiazole, 4-bromo-N,N-bis(4-methoxyphenyl)aniline, tris(dibenzylideneacetone)dipalladium(O) and tris(o-methylphenyl)phosphine is 0.5∶1.1∶0.1∶0.8.

[0017] Further, in step (ii), the reaction under heating conditions is carried out at a temperature of 110°C for a time of 72 hours;

[0018] And / or, during the column chromatography purification, the eluent is a mixture of dichloromethane and petroleum ether in a volume ratio of 1:2.

[0019] Further, in step (iii), the molar ratio of TTBSM, 2,2-dicyanethylene-1,1-bis(thiolate) and tetrabutylammonium bromide is 0.32:0.38:0.063.

[0020] Further, in step (iii), the volume ratio of dichloromethane to water is 1:10;

[0021] And / or, during the column chromatography purification, the eluent is a mixture of dichloromethane and petroleum ether in a volume ratio of 1:3.

[0022] The present invention also provides a nanoparticle prepared by encapsulating the above-mentioned near-infrared II luminescent material with a surfactant.

[0023] Furthermore, the surfactant is DSPE-PEG2000-cRGD.

[0024] The present invention also provides an application of the above-mentioned near-infrared II luminescent material or the above-mentioned nanoparticles in the preparation of bioimaging materials.

[0025] Compared with the prior art, the present invention has the following advantages and technical effects:

[0026] The TTBSMCN prepared in this invention achieves highly efficient emission in the near-infrared II region, with emission wavelengths exceeding 1000 nm and a higher fluorescence quantum yield than existing materials. TTBSMCN exhibits a significant AIE effect in the aggregated state, effectively avoiding the aggregation quenching problem of traditional materials. TTBSMCN NPs demonstrate excellent targeting performance and a high signal-to-noise ratio in bioimaging, enabling high-resolution imaging of tumor regions. Attached Figure Description

[0027] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0028] Figure 1 For TTBSM in CDCl3 1 H NMR (400MHz) spectrum.

[0029] Figure 2 For TTBSM in CDCl3 13 C10 NMR (400MHz) spectrum.

[0030] Figure 3 This is the high-resolution mass spectrometry (HRMS) spectrum of TTBSM.

[0031] Figure 4 For TTBSMCN in CDCl3 1 H NMR (400MHz) spectrum.

[0032] Figure 5 For TTBSMCN in CDCl3 13 C10 NMR (400MHz) spectrum.

[0033] Figure 6 This is a high-resolution mass spectrometry (HRMS) spectrum of TTBSMCN.

[0034] Figure 7 The images show the absorption and emission spectra of compounds TTBSM and TTBSMCN in different states. Image a shows the normalized UV-Vis absorption spectra of TTBSM and TTBSMCN in tetrahydrofuran (THF) and in the solid state, with a concentration of 10 μmol for both TTBSM and TTBSMCN in THF and an excitation wavelength of 540 nm. Image b shows the normalized photoluminescence (PL) spectra of TTBSM and TTBSMCN in tetrahydrofuran and in the solid state, with a concentration of 10 μmol for both TTBSM and TTBSMCN in THF and an excitation wavelength of 540 nm.

[0035] Figure 8The fluorescence spectra and AIE curves of compounds TTBSM and TTBSMCN in different THF / water mixtures at different water contents (0 vol%–90 vol%) are shown, where a represents different water fractions (f w Photoluminescence (PL) spectrum of TTBSM in a tetrahydrofuran / water mixture; b represents the relative emission intensity (I / I0) and wavelength as a function of f. w A changing curve, where I0 is f w The photoluminescence intensity at f = 0, the concentration of TTBSM in the tetrahydrofuran / water mixture is 10 μmol, and the excitation wavelength is 540 nm; c represents different water fractions (f w Photoluminescence (PL) spectrum of TTBSMCN in a tetrahydrofuran / water mixture; d represents the relative emission intensity (I / I0) and wavelength as a function of f. w A changing curve, where I0 is f w The photoluminescence intensity at 0 was determined by the concentration of TTBSMCN in a tetrahydrofuran / water mixture of 10 μmol and the excitation wavelength of 540 nm.

[0036] Figure 9 The molecular packing modes of TTBSM and TTBSMCN and the analysis of non-bonded intermolecular interactions of TTBSM and TTBSMCN in the crystalline state are shown in Figure 1. In Figure 2, a represents the molecular packing mode of TTBSM, b represents the molecular packing mode of TTBSM, c represents the analysis of non-bonded intermolecular interactions of TTBSM in the crystalline state, and d represents the analysis of non-bonded intermolecular interactions of TTBSMCN in the crystalline state.

[0037] Figure 10 The dynamic light scattering spectrum of TTBSMCN nanoparticles (NPs) encapsulated by DSPE-PEG2000-cRGD is shown in the inset, with a transmission electron microscope (TEM) image of the TTBSMCN NPs.

[0038] Figure 11 Normalized absorption and photoluminescence spectra of TTBSMCN NPs in PBS.

[0039] Figure 12 Fluorescence images of T24 cells xenografted mice after intravenous injection of TTBSMCN NPs (a) and quantitative analysis results of tumor fluorescence intensity in T24 cells xenografted mice after intravenous injection of TTBSMCN NPs (b).

[0040] Figure 13 Imaging images of normal urothelial tissue and tumor tissue under bright field and fluorescence field after intravesical instillation of TTBSMCN NPs. Detailed Implementation

[0041] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0042] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0043] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0044] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be obvious to those skilled in the art. This specification and embodiments are merely exemplary.

[0045] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0046] An embodiment of the present invention provides a near-infrared II luminescent material, which is 2-(4,8-bis(5-[4-(bis(4-methoxyphenyl)amino)phenyl]thiophen-2-yl)-[1,3]dithiapento[4′,5′:4,5]no[1,2,5]benzothiadiazole-6-ylidene)malonitrile, denoted as TTBSMCN, with the following structural formula:

[0047]

[0048] Based on the D-π-A-π-D molecular structure, this invention designs a novel material compound, 2-(4,8-bis(5-[4-(bis(4-methoxyphenyl)amino)phenyl]thiophen-2-yl)-[1,3]dithiapento[4′,5′:4,5]no[1,2,5]benzothiadiazole-6-ylidene)malonitrile (TTBSMCN). A comparison with compound 2-4,4'-((5,6-difluoro[1,2,5]thiadiazole[c]phenyl-4,7-diyl)bis(thiophen-5,2-diyl))bis[N,N-bis(4-methoxyphenyl)aniline] (TTBSM) shows that this invention optimizes the molecular stacking by extending the acceptor structure and introducing electron-adsorbing groups.

[0049] The embodiments of the present invention also provide a method for preparing a near-infrared II luminescent material, the synthesis route of which is as follows:

[0050]

[0051] Specifically, the following steps are included:

[0052] Step (i): 5,6-Difluoro-4,7-bis(thiophen-2-yl)[1,2,5]thiadiazole was added to anhydrous tetrahydrofuran, cooled to -78°C, and then diisopropyllithium amine was added. The mixture was stirred until homogeneous at this temperature. A tetrahydrofuran solution of trimethyltin chloride was added, and the mixture was stirred at room temperature. After the reaction was completed, a saturated aqueous solution of potassium fluoride (KF) was added to quench the reaction. The reaction solution was extracted with dichloromethane and water. The organic phase was dried over anhydrous sodium sulfate, filtered, and purified by column chromatography to obtain 5,6-difluoro-4,7-bis[5-(trimethyltin)thiophen-2-yl][1,2,5]thiadiazole.

[0053] Step (ii): Under nitrogen protection, 5,6-difluoro-4,7-bis[5-(trimethyltin)thiophen-2-yl][1,2,5]thiadiazole, 4-bromo-N,N-bis(4-methoxyphenyl)aniline, tris(dibenzylacetone)dipalladium(O) and tris(o-methylphenyl)phosphine were added to anhydrous toluene and stirred until homogeneous. The reaction mixture was then heated. After the reaction was complete, the reaction solution was extracted with water and dichloromethane. The organic phase was dried over anhydrous sodium sulfate, filtered, and purified by column chromatography to obtain TTBSM. The structural formula of TTBSM is [insert structural formula here].

[0054] Step (iii): Under nitrogen protection, TTBSM, 2,2-dicyanethylene-1,1-bis(sodium thiolate) and tetrabutylammonium bromide were added to anhydrous N,N-dimethylformamide and stirred until homogeneous. The reaction mixture was then reacted under heating conditions. After the reaction was completed, the solvent was removed under reduced pressure. The residue was extracted with dichloromethane / water. The organic phase was dried with anhydrous sodium sulfate, filtered, purified by column chromatography, and recrystallized with a dichloromethane / n-hexane mixed solvent to obtain the near-infrared II luminescent material.

[0055] In a preferred embodiment of the present invention, in step (i), the molar ratio of 5,6-difluoro-4,7-bis(thiophen-2-yl)[1,2,5]thiadiazole, diisopropyllithium amine, and trimethyltin chloride is 0.74:2.23:2.23; the volume ratio of dichloromethane to water is 1:10; and during column chromatography purification, the eluent is a mixture of dichloromethane and petroleum ether in a volume ratio of 1:5.

[0056] In a preferred embodiment of the present invention, in step (ii), the molar ratio of 5,6-difluoro-4,7-bis[5-(trimethyltin)thiophen-2-yl][1,2,5]thiadiazole, 4-bromo-N,N-bis(4-methoxyphenyl)aniline, tris(dibenzylacetone)dipalladium(O) and tris(o-methylphenyl)phosphine is 0.5∶1.1∶0.1∶0.8; in step (ii), the reaction temperature under heating conditions is 110°C and the time is 72 h; during column chromatography purification, the eluent is a mixture of dichloromethane and petroleum ether in a volume ratio of 1∶2.

[0057] In a preferred embodiment of the present invention, in step (iii), the molar ratio of TTBSM, 2,2-dicyanethylene-1,1-bis(sodium thiolate) and tetrabutylammonium bromide is 0.32:0.38:0.063; in step (iii), the volume ratio of dichloromethane to water is 1:10; during column chromatography purification, the eluent is a mixture of dichloromethane and petroleum ether, with a volume ratio of 1:3.

[0058] An embodiment of the present invention also provides a nanoparticle prepared by encapsulating the above-mentioned near-infrared II luminescent material with a surfactant.

[0059] In a preferred embodiment of the present invention, the surfactant is DSPE-PEG2000-cRGD.

[0060] Embodiments of the present invention also provide an application of the above-mentioned near-infrared II luminescent material or the above-mentioned nanoparticles in the preparation of bioimaging materials.

[0061] This invention proposes a molecular design strategy based on receptor structure regulation. After introducing malononitrile units into the host TTBSM structure, the newly added functional groups on the receptor alter the arrangement of intermolecular interactions throughout the system. This systematically regulates the molecular stacking in the aggregated state, thereby forming strong intermolecular interactions, suppressing nonradiative transitions, and optimizing the molecular stacking structure to achieve highly efficient NIR-II luminescence. The material of this invention forms a stable dimer stacking structure in the solid state, transforming from monomolecular luminescence to dimer luminescence, significantly improving the emission wavelength and efficiency. Combined with the AIE effect and bioimaging technology, this provides a new strategy and option for highly sensitive NIR-II region bioimaging.

[0062] Unless otherwise specified, the room temperature in this invention is 25±2℃.

[0063] All raw materials used in the embodiments of this invention were purchased commercially. As an example, DSPE-PEG2000-cRGD was purchased from Xi'an Qiyue Biotechnology Co., Ltd.; BALB / c nude mice were purchased from Guangdong Provincial Medical Experimental Animal Center; and T24 cells were purchased from the Cell Bank of the Chinese Academy of Sciences.

[0064] It should be noted that any aspects not described in detail in this invention are conventional practices in the field and are not the focus of this invention.

[0065] The technical solution of the present invention will be further illustrated by the following embodiments.

[0066] Example 1

[0067] A method for preparing a near-infrared II luminescent material, the synthesis route is as follows:

[0068]

[0069] The specific steps are as follows:

[0070] Step (i): 5,6-Difluoro-4,7-bis(thiophen-2-yl)[1,2,5]thiadiazole (250 mg, 0.74 mmol) was placed in a dry, clean 50 mL reaction flask. Anhydrous tetrahydrofuran (15 mL) was added under nitrogen protection, and the reaction solution was cooled to -78 °C. Then, diisopropyllithium amine (LDA, 0.6 M, THF (tetrahydrofuran) / hexane solution, 3.7 mL, 2.23 mmol) was added dropwise, and stirring was continued at this temperature for 10 min. Trimethyltin chloride (444 mg, 2.23 mmol) was dissolved in tetrahydrofuran / hexane. After adding 1.0 mL of furan, it was added dropwise to the reaction system, and the mixture was stirred at room temperature for 12 h. After the reaction was completed, saturated potassium fluoride (KF) aqueous solution was added to the reaction solution for quenching, and the reaction solution was extracted with dichloromethane and water (1:10, volume ratio). The organic phase was dried over anhydrous sodium sulfate, filtered, and purified by column chromatography (eluent: dichloromethane / petroleum ether = 1 / 5, volume ratio) to obtain a white powder solid 5,6-difluoro-4,7-bis[5-(trimethyltin)thiophen-2-yl][1,2,5]thiadiazole (360 mg, yield 73%).

[0071] Step (ii): Under nitrogen protection, 5,6-difluoro-4,7-bis[5-(trimethyltin)thiophen-2-yl][1,2,5]thiadiazole (330 mg, 0.50 mmol), 4-bromo-N,N-bis(4-methoxyphenyl)aniline (421 mg, 1.10 mmol), tris(dibenzylacetone)dipalladium(0) (92 mg, 0.10 mmol) and tris(o-methylphenyl)phosphine (243 mg, 0.80 mmol) were added to anhydrous toluene (10 mL) and stirred until homogeneous. The reaction mixture was heated at 110 °C for 72 h. After the reaction was completed, the reaction solution was extracted with water and dichloromethane (1:10, v / v). The organic phase was dried over anhydrous sodium sulfate, filtered, and purified by column chromatography (eluent: dichloromethane / petroleum ether = 1 / 2, v / v) to obtain brown powdery solid TTBSM (369 mg, yield 78%). 1 H NMR (500MHz, CDCl3) δ8.23(d,J=3.7Hz,2H),7.52(d,J=8.4Hz,4H),7.29(s,2 H),7.09(d,J=6.6Hz,8H),6.93(s,4H),6.86(d,J=8.7Hz,8H),3.82(s,12H). 13C NMR(126MHz, CDCl3)δ156.21(s),150.73(s),148.86(s),147.84(s),140.37(s),132.07(s),126. 93(s),126.65(s),122.19(s),120.43(s),114.74(s),111.47(s),55.52(s).HRMS(ESI):m / z:calc for[M],[M+H] + C 54 H 40 F2N4O4S3:942.2180,found:942.2177,943.2221.

[0072] Figure 1 For TTBSM in CDCl3 1 H NMR (400MHz) spectrum; Figure 2 For TTBSM in CDCl3 13 C NMR (400MHz) spectrum; Figure 3 This is the high-resolution mass spectrometry (HRMS) spectrum of TTBSM.

[0073] Step (iii): Under nitrogen protection, TTBSM (300 mg, 0.32 mmol), 2,2-dicyanethylene-1,1-bis(thiolate) (71 mg, 0.38 mmol), and tetrabutylammonium bromide (21 mg, 0.063 mmol) were added to anhydrous N,N-dimethylformamide (50 mL) and stirred until homogeneous. The reaction mixture was heated at 110 °C for 72 h. After the reaction was completed, the solvent was removed under reduced pressure. The residue was extracted with dichloromethane / water (1:10, v / v). The organic phase was dried over anhydrous sodium sulfate, filtered, and purified by column chromatography (eluent: dichloromethane / petroleum ether = 1 / 3, v / v). The purified solid was then recrystallized from a dichloromethane / n-hexane (1:10, v / v) mixture to obtain a dark crystalline solid, TTBSMCN (185 mg, yield 56%). 1 H NMR(500MHz, CDCl3) δ7.67(d,J=3.5Hz,2H),7.50(d,J=7.0Hz,4H),7.31(s,2 H),7.09(s,8H),6.92(d,J=4.2Hz,4H),6.87(d,J=8.2Hz,8H),3.82(s,12H). 13C NMR(126MHz,Chloroform-d)δ177.21,156.44,152.36,149.49,136.21,131.52,126.95(d,J =47.6Hz),122.16,120.03,114.75,67.51,55.53,31.61,22.68,14.16.HRMS(ESI):m / z:calc for[M],[M+H] + C 58 H 40 N6O4S5:1044.1715,found:1044.1709,1045.1733.

[0074] Figure 4 For TTBSMCN in CDCl3 1 H NMR (400MHz) spectrum; Figure 5 For TTBSMCN in CDCl3 13 C NMR (400MHz) spectrum; Figure 6 This is a high-resolution mass spectrometry (HRMS) spectrum of TTBSMCN.

[0075] The performance of the synthesized TTBSM and TTBSMCN was tested as follows:

[0076] (1) Optical performance testing

[0077] TTBSM and TTBSMCN were dissolved in tetrahydrofuran (THF) at a concentration of 10 μmol each. The absorption and fluorescence emission spectra of TTBSM and TTBSMCN were measured in both solution and solid states, with an excitation wavelength of 540 nm. The effect of solvent polarity on optical properties was investigated to verify the solvation effect of the materials.

[0078] The absorption and emission spectra of compounds TTBSM and TTBSMCN in different states are as follows: Figure 7 As shown, the emission wavelength of compound TTBSM in THF is 765 nm, and the emission wavelength in the solid state is 741 nm; while the emission wavelength of TTBSMCN in THF is 735 nm, and the emission wavelength in the solid state is 928 nm.

[0079] (2) Aggregation-induced emission (AIE) properties

[0080] The fluorescence intensity of compounds TTBSM and TTBSMCN was tested at different water / THF mixing ratios. AIE curves were plotted based on the changes in fluorescence intensity to analyze the effect of molecular aggregation behavior on luminescence properties.

[0081] Fluorescence spectra and AIE curves of compounds TTBSM and TTBSMCN in THF / water mixtures with different water contents (0 vol%–90 vol%) are shown below. Figure 8 As shown, it can be clearly observed that with the increase of water content, the spectrum of TTBSMCN redshifts and the fluorescence intensity increases after the formation of aggregates.

[0082] (3) Single crystal structure analysis

[0083] Using X-ray single-crystal diffraction, the molecular packing modes of TTBSM and TTBSMCN were analyzed and intermolecular interactions were calculated. The molecular packing modes of TTBSM and TTBSMCN, as well as the analysis of non-bonded intermolecular interactions of TTBSM and TTBSMCN in the crystalline state, are as follows: Figure 9 As shown, it was found that TTBSMs form a stable dimer structure in the solid state, while TTBSMs are mainly stacked at dislocations, which may be the key to the redshift of TTBSMs in the aggregate state.

[0084] Application Example 1: Bioimaging Applications

[0085] 2 mg TTBSMCN and 10 mg DSPE-PEG2000-cRGD were mixed in 2 mL THF and emulsified under ultrasonic conditions (150 W, 10 mins, frequency: 0.5 s on, 0.5 s off) to form an oil-water emulsion. Simultaneously, 10 mL of PBS buffer (pH = 7.4) was added, followed by rotary evaporation (room temperature, overnight) to remove the organic solvent, forming a uniform nanoparticle suspension. Finally, the suspension was dialyzed with PBS buffer (pH = 7.2-7.4) for 24 hours to remove free material and excess surfactant, yielding a TTBSMCNNPs suspension. Dynamic light scattering (DLS) of particle size and distribution was measured using a Zetasizer Nano ZS. 5 μL of the suspension was dropped onto a carbon film copper grid, dried, and then characterized by transmission electron microscopy (TEM) to determine the nanoparticle size and morphology, and to measure its optical properties.

[0086] Figure 10 The image shows the dynamic light scattering spectrum of TTBSMCN nanoparticles (NPs) encapsulated with DSPE-PEG2000-cRGD. The inset shows a transmission electron microscope (TEM) image of the TTBSMCN NPs, demonstrating that the present invention utilizes surfactant-modified materials to form stable TTBSMCN NP nanoparticles.

[0087] Figure 11The normalized absorption and photoluminescence spectra of TTBSMCN NPs in PBS show that after nanoengineering, TTBSMCN NPs exhibit absorption in the visible light band and strong fluorescence emission in the NIR-II region (>1000 nm), which is consistent with the large Stokes shift phenomenon exhibited by the aggregated state of TTBSMCN. Through nanoengineering, molecular aggregation is achieved, which changes the material's luminescent building blocks and enables the material to emit near-infrared II light.

[0088] To verify the tumor imaging capability of nanoparticles in vivo, this invention uses BALB / c nude mice and establishes a tumor model by subcutaneously inoculating T24 cells: First, TTBSMCN NPs suspension is injected into mice via the tail vein at a dose of 1 mg / kg, and the fluorescence image signals in the small animal in vivo imaging system are recorded at 1 hour, 4 hours, 12 hours, 24 hours, 36 hours, 48 ​​hours and 72 hours after injection, and 3 sets of repetitions are performed to quantify the signal intensity in the tumor area.

[0089] Fluorescence images of T24 cell xenograft mice after intravenous injection of TTBSMCN NPs (a) and quantitative analysis results of tumor fluorescence intensity in T24 cell xenograft mice after intravenous injection of TTBSMCN NPs (b) are shown below. Figure 12 As shown, TTBSMCN NPs can clearly display the contour of the tumor region in small animal fluorescence imaging, and the imaging effect is still significant even 72 hours after administration.

[0090] In a mouse orthotopic bladder tumor model, the fluorescence distribution of the material at the tumor site was observed through bladder instillation to verify its imaging targeting ability and determine whether the tumor boundary was clearly marked. To further demonstrate the effectiveness of local drug delivery of nanoparticles, this invention established a mouse orthotopic bladder tumor model. The mouse bladder was exposed through a small laparotomy (incision ≈ 1 cm), and after urine was aspirated, 50 μL of T24 cell suspension (0.5-5 × 10⁻⁵) was administered. 6 Cells (50 μL) were directly injected into the bladder cavity without pretreatment of the urothelium or bladder wall. Postoperatively, water was withheld for 1 hour to promote cell adhesion. Within 4 weeks, spontaneous muscle layer invasion and lymphovascular invasion of tumors occurred, with pathological features highly mimicking human disease. Subsequently, the TTBSMCN NPs suspension was perfused into the mouse bladder via catheter. Two hours after perfusion, the bladder was repeatedly flushed with PBS, and bright-field and fluorescence imaging was performed after bladder dissection.

[0091] Imaging images of normal urothelial tissue and tumor tissue under bright field and fluorescence field after intravesical instillation of TTBSMCN NPs are shown below. Figure 13 As shown, the fluorescence signal of TTBSMCN NPs can clearly show the outline and boundary of the bladder tumor in situ.

[0092] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A near-infrared II luminescent material, characterized in that, It is 2-(4,8-bis(5-[4-(bis(4-methoxyphenyl)amino)phenyl]thiophene-2-yl)-[1,3]dithia-penta[4',5':4,5]benzo[1,2,5]thiadiazole-6-ylidene)malonitrile, and its structural formula is as follows:

2. A method for producing the near infrared two-band luminescent material according to claim 1, characterized by, The method comprises the following steps: Step (i): 5,6-difluoro-4,7-bis(thiophene-2-yl)benzo[1,2,5]thiadiazole is added into anhydrous tetrahydrofuran, cooled to-78℃, diisopropyl lithium amine is added, and stirred uniformly at the temperature, a tetrahydrofuran solution of trimethyl tin chloride is added, the reaction is stirred at room temperature, after the reaction is completed, saturated potassium fluoride aqueous solution is added for quenching, the reaction liquid is extracted with dichloromethane and water, the organic phase is dried with anhydrous sodium sulfate, filtered, and purified by column chromatography to obtain 5,6-difluoro-4,7-bis[5-(trimethyl tin)thiophene-2-yl]benzo[1,2,5]thiadiazole; Step (ii): 5,6-difluoro-4,7-bis[5-(trimethyltin)thiophen-2-yl] [1,2,5]thiadiazole, 4-bromo-N,N-bis(4-methoxyphenyl)aniline, tris(dibenzylideneacetone)dipalladium(0) and tri(o- tolyl)phosphine were added into anhydrous toluene, stirred uniformly, the reaction mixture was reacted under heating condition, after the reaction was completed, the reaction liquid was extracted with water and dichloromethane, the organic phase was dried over anhydrous sodium sulfate, filtered, and purified by column chromatography to obtain TTBSM, the structural formula of the TTBSM is Step (iii): under nitrogen protection, TTBSM, 2,2-dicyanoethylene-1,1-bis(sodium mercaptan) and tetrabutylammonium bromide are added into anhydrous N,N-dimethylformamide, stirred uniformly, the reaction mixture is reacted under heating, after the reaction is completed, the solvent is removed under reduced pressure, the residue is extracted with dichloromethane and water, the organic phase is dried with anhydrous sodium sulfate, filtered, and purified by column chromatography, and recrystallized by using a dichloromethane / n-hexane mixed solvent to obtain the near-infrared two-region light-emitting material.

3. The method of producing a near-infrared two-band luminescent material according to claim 2, wherein In step (i), the molar ratio of 5,6-difluoro-4,7-bis(thiophene-2-yl)benzo[1,2,5]thiadiazole, diisopropyl lithium amine and trimethyl tin chloride is 0.74:2.23:2.

23.

4. The method of producing a near-infrared two-band luminescent material according to claim 2, wherein In step (i), the volume ratio of dichloromethane to water is 1:

10. And / or, when the column chromatography is purified, the eluent is a mixture of dichloromethane and petroleum ether, and the volume ratio of the two is 1:

5.

5. The method of producing a near-infrared two-band luminescent material according to claim 2, wherein In step (ii), the molar ratio of 5,6-difluoro-4,7-bis[5-(trimethyl tin)thiophene-2-yl]benzo[1,2,5]thiadiazole, 4-bromo-N,N-bis(4-methoxyphenyl)aniline, tris(dibenzylideneacetone)dipalladium(0) and tri(o-methylphenyl)phosphine is 0.5:1.1:0.1:0.

8.

6. The method of producing a near-infrared two-band luminescent material according to claim 2, wherein In step (ii), the reaction is carried out under heating at a temperature of 110℃ for 72h. And / or, when the column chromatography is purified, the eluent is a mixture of dichloromethane and petroleum ether, and the volume ratio of the two is 1:

2.

7. The method of producing a near-infrared two-band luminescent material according to claim 2, wherein In step (iii), the molar ratio of TTBSM, 2,2-dicyanoethylene-1,1-bis(sodium mercaptan) and tetrabutylammonium bromide is 0.32:0.38:0.

063.

8. The method of producing a near-infrared two-band luminescent material according to claim 2, wherein In step (iii), the volume ratio of dichloromethane to water is 1:

10. And / or, when the column chromatography is purified, the eluent is a mixture of dichloromethane and petroleum ether, and the volume ratio of the two is 1:

3.

9. A nanoparticle, characterized in that, The near-infrared two-region light-emitting material of claim 1 is prepared by being wrapped with a surfactant.

10. Use of a near-infrared two-region luminescent material according to claim 1 or nanoparticles according to claim 9 for the preparation of a bioimaging material.

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