A method for preparing a heat-activated delayed fluorescence polysulfur aromatic compound

Abstract

The present application relates to a kind of preparation methods of heat-activated delayed fluorescent polysulfide aromatic compound, the heat-activated delayed fluorescent polysulfide aromatic compound prepared in the present application can be in the mixed solution of aqueous phase, organic phase, realize fluorescence enhancement or quenching by oxygen removal;When it is used for biological cell imaging, after entering cell, the intensity of fluorescence is gradually enhanced with the extension of oxygen removal time by the means of continuous oxygen removal, so as to realize the effect of cell imaging visualization, and ensure clearer imaging effect;Target molecule effectively combines phosphorescent material and heat-activated delayed fluorescent performance, realizes multifunctional time-resolved imaging technology, wherein, the compound prepared in the present application has the property of delayed fluorescence, material structure is controllable, and stable, provides the feasibility for cell imaging.

Description

TECHNICAL FIELD

[0001] The present application relates to a preparation method of a thermally activated delayed fluorescence polysulfur aromatic compound. BACKGROUND

[0002] Thermally activated delayed fluorescence (TADF) materials have unique optical and electronic properties, which can be attributed to a small enough energy gap (ΔEST) between the singlet (S1) and triplet (T1) states, enabling efficient reverse intersystem crossing (RISC) processes and thus achieving internal quantum efficiencies (IQEs) of ≈100%.

[0003] Generally, TADF has two light-emitting mechanisms: prompt fluorescence (PF) and delayed fluorescence (DF). This unique optical property makes TADF materials indispensable in biomedical research and clinical applications. Traditional fluorescence imaging relies on light excitation to obtain fluorescence signals, showing biological tissues, and inevitably produces autofluorescence signals and background interference. The long-lived emission characteristics of TADF materials enable fluorescence lifetime imaging (FLIM) and time-resolved luminescence imaging (TRLI) capabilities, which can eliminate background signal interference and improve the accuracy of biological imaging. However, due to weak spin-orbit coupling (SOC), most TADF molecules still have aggregation quenching (ACQ) phenomena, singlet-triplet annihilation (STA), and even triplet-triplet annihilation (TTA) problems, affecting the imaging effect of the material.

[0004] Therefore, the current thermally activated delayed fluorescence (TADF) material and preparation method need to be further improved. SUMMARY

[0005] The technical problem solved by the present application is to provide a preparation method of a thermally activated delayed fluorescence polysulfur aromatic compound that can ensure the enhancement of heavy atom effect and spin-orbit coupling (SOC) to reduce the self-fluorescence interference of biological tissues and improve the accuracy of imaging.

[0006] The technical solution adopted by the present application to solve the above technical problems is:

[0007] A preparation method of a thermally activated delayed fluorescence polysulfur aromatic compound, characterized in that:

[0008] The structure of the thermally activated delayed fluorescence polysulfur aromatic compound is:

[0009]

[0010] wherein X is one of H, O, and S atoms, and Y is a —CH3 group.

[0011] The target product is obtained by condensation reaction with hexathiohexacarboxylic acid as a mother nucleus and peripheral amine group derivatives.

[0012] In the present application, the amine group derivative is phenothiazine, phenoxazine or acridine.

[0013] Preferably, X in the present application is H; the preparation method is as follows:

[0014] (1) Compound M-2 hexathiohexacarboxylic acid is dissolved in DMF (15 mL), 1.0-3.0 g of 2-(7-azobenzotriazole)-N,N,N',N'-tetramethyluronium hexafluorophosphate (HATU) is added, stirred under nitrogen protection for 15-30 min, compound M-1 is added, and 1-2 mL of N,N-diisopropyl ethylamine (DIPEA) is added, and the reaction is carried out at room temperature for 24-48 h;

[0015]

[0016] (2) The obtained crude compound is washed with water, ethanol and acetone to obtain yellow powder compound M-3, which is the target product.

[0017] Preferably, X in the present application is S; the preparation method is as follows:

[0018] (1) Compound M-2 hexathiohexacarboxylic acid is dissolved in DMF (15 mL), 1.5 g of 2-(7-azobenzotriazole)-N,N,N',N'-tetramethyluronium hexafluorophosphate (HATU) is added, stirred under nitrogen protection for 15-30 min, 450 mg of compound M-1 is added, and 1.5 mL of N,N-diisopropyl ethylamine (DIPEA) is added, and the reaction is carried out at room temperature for 24-48 h;

[0019]

[0020] (2) The obtained crude compound is washed with water, ethanol and acetone to obtain yellow powder compound M-3, which is the target product.

[0021] Preferably, X in the present application is O; the preparation method is as follows:

[0022] (1) Compound M-2 hexathiohexacarboxylic acid is dissolved in DMF (15 mL), 1.5 g of 2-(7-azobenzotriazole)-N,N,N',N'-tetramethyluronium hexafluorophosphate (HATU) is added, stirred under nitrogen protection for 15-30 min, 550 mg of compound M-1 is added, and 1.5 mL of N,N-diisopropyl ethylamine (DIPEA) is added, and the reaction is carried out at room temperature for 24-48 h;

[0023]

[0024] (2) The obtained crude compound is washed with water, ethanol and acetone to obtain a yellow powder compound M-3, which is the target product.

[0025] Compared with the prior art, the present application has the advantages that:

[0026] (1) The heat-activated delayed fluorescent polysulfur aromatic compound of the present application can realize fluorescence enhancement or quenching in a mixed solution of an aqueous phase and an organic phase by oxygen removal; when it is used for biological cell imaging, the intensity of fluorescence is gradually enhanced with the extension of oxygen removal time after the molecule enters the cell, so that the effect of cell imaging visualization is realized, and a clearer imaging effect is ensured;

[0027] (2) The heat-activated delayed fluorescent polysulfur aromatic compound of the present application can realize rapid fluorescence change phenomenon; the target molecule effectively combines the performance of phosphorescent material and heat-activated delayed fluorescence, realizes multifunctional time-resolved imaging technology, wherein the compound prepared by the present application has the property of delayed fluorescence, the material structure is controllable, the property is stable, and the feasibility for cell imaging is provided.

[0028] (3) The polysulfur compound obtained by the preparation method of the present application provides strong electronic energy donation ability and high-energy electron orbit, so as to ensure that the heavy atom effect enhances the spin-orbit coupling (SOC) and inhibits the non-radiation relaxation, thereby reducing the self-fluorescence interference of biological tissues and improving the imaging accuracy;

[0029] (4) The heat-activated delayed fluorescent polysulfur aromatic compound in the present application has good biological compatibility, no toxicity, and the raw materials are cheap and easy to obtain, the synthesis route is simple, and the industrial production is easy. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 The fluorescence spectrum of the heat-activated delayed fluorescent material obtained in Example 1 of the present application under 365nm laser irradiation in a mixed solvent of multiple groups of aqueous solution / organic phase; 1 HNMR spectrum;

[0031] Figure 2 The fluorescence spectrum of the heat-activated delayed fluorescent material obtained in Example 1 of the present application under 365nm laser irradiation in a mixed solvent of multiple groups of aqueous solution / organic phase;

[0032] Figure 3 The lifetime fitting graph of the heat-activated delayed fluorescent material obtained in Example 1 of the present application under temperature change test;

[0033] Figure 4 The imaging graph of the heat-activated delayed fluorescent material obtained in Example 1 of the present application in HeLa cells. DETAILED DESCRIPTION

[0034] The application will be further described in detail below with reference to the accompanying drawings.

[0035] Example 1:

[0036] The structure of the heat-activated delayed fluorescent polysulfur aromatic compound of this example is as follows:

[0037]

[0038] The preparation method of the heat-activated delayed fluorescent polysulfur aromatic compound of this example is as follows:

[0039] (1) 100 mg of compound M-2 hexacarboxylic acid hexathiophene was dissolved in DMF (15 mL), 1.5 g of 2-(7-azobenzotriazole)-N,N,N',N'-tetramethyluronium hexafluorophosphate (HATU) was added, stirred for 30 min under nitrogen protection, 500 mg of compound M-1 and 1.5 mL of N,N-diisopropyl ethylamine (DIPEA) were added, and the reaction was carried out at room temperature for 24 h;

[0040]

[0041] (2) The crude compound was washed with water, ethanol and acetone to obtain yellow powder compound M-3, which is the target product.

[0042] Figure 1 The structure of the heat-activated delayed fluorescent polysulfur aromatic compound of this example is as follows: 1 HNMR spectrum,

[0043] 1 H NMR (400 MHz, DMSO-d6): δ 10.47 (s, 6H), 8.11-8.04 (m, 12H), 8.04-7.95 (m, 12H), 7.49-7.39 (m, 13H), 7.37-7.21 (m, 24H), 6.90-6.76 (m, 23H), 6.22-6.14 (m, 12H), 1.55 (s, 36H).

[0044] Example 2:

[0045] The structure of the heat-activated delayed fluorescent polysulfur aromatic compound of this example is as follows:

[0046]

[0047] The preparation method of the heat-activated delayed fluorescent polysulfur aromatic compound of this example is as follows:

[0048] (1) 100 mg of the following compound M-2 hexacarboxylic acid hexathio benzene is dissolved in DMF (15 mL), 1.5 g of 2-(7-azobenzotriazole)-N,N,N',N'-tetramethyluronium hexafluorophosphate (HATU) is added, stirred for 15-30 min under nitrogen protection, 450 mg of the following compound M-1 and 1.5 mL of N,N-diisopropyl ethylamine (DIPEA) are added, and the reaction is carried out at room temperature for 24 h-48 h;

[0049]

[0050] (2) The obtained crude compound is washed with water, ethanol and acetone to obtain yellow powder compound M-3, which is the target product.

[0051] Example 3:

[0052] The structure of the thermally activated delayed fluorescent polysulfur aromatic compound of the present example is as follows:

[0053]

[0054] The preparation method of the thermally activated delayed fluorescent polysulfur aromatic compound of the present example is as follows:

[0055] (1) 100 mg of the following compound M-2 hexacarboxylic acid hexathio benzene is dissolved in DMF (15 mL), 1.5 g of 2-(7-azobenzotriazole)-N,N,N',N'-tetramethyluronium hexafluorophosphate (HATU) is added, stirred for 15-30 min under nitrogen protection, 550 mg of the following compound M-1 and 1.5 mL of N,N-diisopropyl ethylamine (DIPEA) are added, and the reaction is carried out at room temperature for 24 h-48 h;

[0056]

[0057] (2) The obtained crude compound is washed with water, ethanol and acetone to obtain yellow powder compound M-3, which is the target product.

[0058] The product prepared in Example 1 is subjected to performance detection.

[0059] The activated delayed fluorescent polysulfur aromatic compound prepared in Example 1 is added to a mixed solution of different proportions of organic phase / water phase (the volume ratio of water phase / organic phase is 0%, 50%, 80%, 85%, 95% respectively), and the organic phase is tetrahydrofuran, then it is added to a fluorescence cuvette, and under 365 nm laser irradiation, the various fluorescence color change phenomena of the polyaryl sulfur luminescent material are observed. The results are as follows Figure 2 This shows that the material can effectively adjust the fluorescence color change by adjusting the proportion of organic phase / water phase.

[0060] Temperature test was performed on the product prepared in Example 1.

[0061] The activated delayed fluorescence polysulfur aromatic compound prepared in Example 1 was added into the biological cells at a concentration of 10 -5 M (volume ratio of aqueous phase / THF = 85%) into a fluorescence cuvette, and was cooled to 77K by adding liquid nitrogen in a low-temperature device. During the process of continuously increasing the temperature, it was observed that the previous part of the lifetime curve rose upward, accompanied by a decrease in phosphorescent lifetime, i.e. the compound of the present application simultaneously had the effects of thermal activation delay and room temperature phosphorescence. This indicated that the material synthesized in the present application could effectively adjust the changes in fluorescence and phosphorescence through temperature means. Figure 3

[0062] Cell imaging test was performed on the product prepared in Example 1.

[0063] The activated delayed fluorescence polysulfur aromatic compound prepared in Example 1 was added into the biological cells at a concentration of 10 -4 M (prepared with cell nutrient solution, selected from Plonex DMEM high-sugar culture solution) into the biological cells, and cell imaging was observed by confocal observation in a deoxygenated manner. As shown in Figure 4 , in the aqueous phase, the imaging images of HeLa cells before deoxygenation (group a) under different lasers (405 nm, 488 nm, 561 nm, respectively) were unclear; the deoxygenated HeLa cells (group b) under different lasers (405 nm, 488 nm, 561 nm) could achieve clear cell imaging effect. The results showed that the material of the present application could achieve the effect of biological imaging visualization in cells through deoxygenation.​

Claims

1. A method for preparing a thermally activated delayed fluorescence polysulfur aromatic compound, characterized in that: the thermally activated delayed fluorescence polysulfur aromatic compound has the following structural formula: wherein X is one of C, O, and S; and when X is C, Y is a -CH3 group.

2. The method for producing a thermally activated delayed fluorescence polysulfur aromatic compound according to claim 1, characterized by: X is C; (1) dissolving the following compound M-2 hexacarboxylic acid hexathiophene in DMF, adding 2-(7-azobenzo triazole)-N,N,N',N'-tetramethyl urea hexafluorophosphate, stirring under nitrogen protection for 15-30 min, adding the following compound M-1, and 1-2 mL of N,N-diisopropyl ethylamine, and reacting at room temperature for 24-48 h; (2) washing the obtained crude compound with water, ethanol, and acetone to obtain a yellow powder compound M-3, which is the target product.

3. The method for preparing thermally activated delayed-fluorescence polysulfide aromatic compounds according to claim 1, characterized in that: X is S; (1) dissolving the following compound M-2 hexacarboxylic acid hexathiophene in DMF, adding 2-(7-azobenzo triazole)-N,N,N',N'-tetramethyl urea hexafluorophosphate, stirring under nitrogen protection for 15-30 min, adding the following compound M-1, and N,N-diisopropyl ethylamine, and reacting at room temperature for 24-48 h; (2) washing the obtained crude compound with water, ethanol, and acetone to obtain a yellow powder compound M-3, which is the target product.

4. The method for preparing thermally activated delayed-fluorescence polysulfide aromatic compounds according to claim 1, characterized in that: X is O; (1) dissolving the following compound M-2 hexacarboxylic acid hexathiophene in DMF, adding 2-(7-azobenzo triazole)-N,N,N',N'-tetramethyl urea hexafluorophosphate, stirring under nitrogen protection for 15-30 min, adding the following compound M-1, and N,N-diisopropyl ethylamine, and reacting at room temperature for 24-48 h; (2) washing the obtained crude compound with water, ethanol, and acetone to obtain a yellow powder compound M-3, which is the target product.

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