Synthesis method of boron-nitrogen heterocyclic ring purple dye and application of boron-nitrogen heterocyclic ring purple dye in aggregation-induced emission and photo-thermal conversion

Abstract

The invention provides a synthesis method of a boron-nitrogen heterocyclic ring purple dye and application of the boron-nitrogen heterocyclic ring purple dye in the aspects of aggregation-induced emission and photo-thermal conversion, and relates to the technical field of design, synthesis and application of functional dyes. According to the preparation method, a boron-nitrogen heterocyclic ring compound with a morpholine group, N-iodosuccinimide (NIS), 1-(4-phenylboronic acid pinacol ester)-1, 2, 2-triphenylethylene and 4-ethynyl triphenylamine are taken as main raw materials, and the boron-nitrogen heterocyclic ring purple dye of which the two sides are respectively connected with a triphenylamine group and a tetraphenylethylene group is generated through two times of electrophilic substitution and coupling reaction. The invention provides a feasible synthesis route and method, a purple end product is obtained, and the product shows the aggregation-induced emission characteristic in a test and has certain photo-thermal conversion capacity, so that the product is expected to be applied to the fields of aggregation-induced emission, photo-thermal conversion, photo-thermal antibiosis and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of design, synthesis and application of functional dyes, in particular to a synthesis method of boron-nitrogen heterocyclic purple dye and its application in aggregation-induced emission and photo-thermal conversion. BACKGROUND

[0002] Purple dyes are widely used in textile printing and dyeing, ink and paint, food and cosmetics, scientific research and industry, etc. due to their symbol of nobility and elegance. The common purple dyes on the market mainly include aniline violet, anthraquinone dyes (such as dye violet 59) and violet 23, etc. However, these dyes generally have poor solubility, high toxicity, easy quenching of luminescence in the aggregated state, and single function (such as only coloring function), etc. Therefore, it is of great significance to develop new purple dyes with multiple functions.

[0003] Aggregation-induced emission (AIE) is a special luminescence phenomenon: these molecules hardly emit light in dilute solution, but show strong fluorescence in high concentration, aggregated state or solid state [K. Ren, B. Zhang, J. Guo, H. Cao, J. Cheng, J. Guo, D. Li, Biosensors and Bioelectronics, 2025, 271, 117067.]. Traditional fluorescent dyes will produce aggregation state quenching phenomenon, but dyes with AIE effect have excellent coloring performance of dyes and unique luminescent characteristics of AIE materials. AIE molecules emit stronger light in solid state or high concentration conditions, so they are very suitable for systems with high aggregation state such as fibers, films, coatings, nanoparticles, etc. This characteristic makes AIE dyes have broad application prospects in the fields of biological imaging, chemical sensing, optoelectronic devices, anti-counterfeiting identification, etc. [Y. Zeng, D. Huang, B. Li, J. Wang, R. Hu, Polymer Chemistry, 2025, 16, 1897.].

[0004] Photo-thermal conversion dyes refer to a class of functional dyes that can absorb light energy and convert it into heat energy efficiently. Compared with simple light-absorbing dyes, these dyes not only have high energy conversion capacity, but also can achieve precise heat energy release in different environments and application scenarios. Therefore, they have a wide range of uses [Z. Gong, G. Kang, R. Shi, X. Jiang, X. Rong, X. Du, J. Wu, H. Huang, S. Meng, Advanced Optical Materials 2024, 12, 2303033; T.-T. Duong Phama, L. M. T. Phan, S. Cho, J. Park, Science and Technology of Advanced Materials, 2022, 23, 707.]. For example, in the field of biological medicine, they are the core materials of photothermal therapy, which can quickly raise the temperature of the lesion area by near-infrared light irradiation, thereby killing cancer cells or bacteria. In the field of intelligent and functional materials, photo-thermal conversion dyes can be used in thermal-driven actuators, soft robots, thermochromic coatings, and information encryption and anti-counterfeiting technology; at the same time, they can also be introduced into fibers or coatings to prepare intelligent textiles that can absorb sunlight and achieve warmth. In the field of energy and environment, these dyes can be applied in solar steam generation and seawater desalination, wastewater purification, and photo-thermal catalytic reactions to improve energy utilization efficiency, etc.

[0005] The present application aims to synthesize a purple dye with excellent solubility, which not only has excellent coloring performance, but also has aggregation-induced emission and photo-thermal conversion ability, thereby expanding its application potential in the fields of biological imaging, organic semiconductors, photo-thermal functional materials, and photo-thermal antibacterial materials, etc. SUMMARY

[0006] The present application provides a synthesis method of boron-nitrogen heterocyclic purple dye and its application in aggregation-induced emission and photo-thermal conversion.

[0007] The technical solutions adopted by the present application are as follows:

[0008] Firstly, the present application proposes a synthesis method of boron-nitrogen heterocyclic purple dye, and the synthesis route is as follows:

[0009]

[0010] The preparation method comprises the following steps in sequence:

[0011] Step a: Compound 1 and NIS are dissolved in an organic solvent to generate compound 2, wherein the molar ratio of compound 1 and NIS is 0.9:0.7-0.8, the reaction is carried out at room temperature, and the reaction time is 0.5 h;

[0012] Step b: Compound 2, raw material 3 and K2CO3 are dissolved in an organic solvent to synthesize compound 4 under the catalysis of Pd(PPh3)4, wherein the molar ratio of compound 2, raw material 3, K2CO3 and Pd(PPh3)4 is 0.9:1.2-1.5:1.5-1.8:0.10-0.12, the reaction temperature is 70-80 ℃, and the reaction time is 6-11 h;

[0013] Step c: Compound 4 and NIS are dissolved in an organic solvent to generate compound 5, wherein the molar ratio of compound 4 and NIS is 0.9:0.5-1.0, the reaction is carried out at room temperature, and the reaction time is 1.5 h;

[0014] Step d: Compound 5, raw material 6, PPh3 and Pd2(dba)3 are dissolved in an organic solvent to generate compound Z, wherein the molar ratio of compound 5, raw material 6, PPh3 and Pd2(dba)3 is 0.9:2.5-2.7:1.6-1.8:0.5-0.6, the reaction temperature is 80-90 ℃, and the reaction time is 1.5-2.5 h.

[0015] As a preferred technical scheme of the present application, the step a is specifically operated as follows: compound 1 and NIS are mixed and placed in a single-necked round-bottom flask, CHCl3 / CH3COOH (v / v = 2 / 1) mixed solvent is added, and then ultrasonic dissolution is carried out, followed by reaction at room temperature, and TLC is used to monitor the reaction progress; after the TLC shows that the raw material is consumed, the reaction is stopped; saturated sodium thiosulfate aqueous solution and CH2Cl2 are used to extract the reaction, CH3COOH is removed, the organic phase is combined after extraction for three times, anhydrous Na2SO4 is added for drying treatment to remove water; the solvent is removed by reduced pressure distillation to obtain a crude product, and column chromatography is used to separate to obtain compound 2.

[0016] As a preferred technical scheme of the present application, the step b is specifically operated as follows: compound 2, raw material 3 and K2CO3 are ultrasonically dissolved in a mixed solvent of freshly distilled tetrahydrofuran and water (v / v = 20 / 3), and are placed in a three-necked round-bottom flask; nitrogen is continuously introduced for 30 min at room temperature to remove oxygen in the reaction; after the end, Pd(PPh3)4 is quickly added as a catalyst and the reaction is sealed; the reaction is placed in a 70 ℃ oil bath to carry out the reaction, and TLC is used for monitoring until the raw material disappears to stop the reaction; after cooling to room temperature, water and CH2Cl2 are used for repeated extraction, the organic phase is combined, and anhydrous Na2SO4 is added for drying; rotary evaporation is used to remove the organic solvent to obtain a crude product, which is separated and purified by column chromatography to obtain compound 4.

[0017] As a preferred technical scheme of the present application, the step c is specifically operated as follows: compound 4 is mixed with NIS and placed in a single-necked round-bottom flask, CHCl3 / CH3COOH (v / v = 2 / 1) mixed solvent is added, ultrasonic dissolution is carried out, and then reaction is carried out at room temperature; TLC is used for monitoring the reaction progress; after the TLC shows that the raw material is consumed, the reaction is stopped; saturated aqueous sodium thiosulfate and CH2Cl2 are used for extraction to remove CH3COOH, the extraction is carried out for multiple times, the organic phase is combined, anhydrous Na2SO4 is added for drying, and water is removed; the solvent is removed by distillation under reduced pressure to obtain a crude product, which is separated by column chromatography to obtain compound 5.

[0018] As a preferred technical scheme of the present application, the step d is specifically operated as follows: compound 5 and raw material 6 are mixed and added to a three-necked round-bottom flask, and a mixed solvent of toluene / triethylamine (v / v = 1 / 1) is added, and ultrasonic dissolution is carried out; nitrogen is continuously introduced for 30 min at room temperature to remove oxygen in the reaction; after the end, PPh3 and Pd2(dba)3 are quickly added and the reaction is sealed; the reaction is moved to an 80 ℃ oil bath to continue the reaction, and TLC is used for monitoring until the raw material completely disappears to stop the reaction; after cooling to room temperature, water and CH2Cl2 are used for extraction, the extraction is carried out for multiple times, the organic phase is combined, and anhydrous Na2SO4 is added for drying; then the organic solvent is removed under reduced pressure, and column chromatography is used for separation to obtain the final compound Z.

[0019] The boron-nitrogen heterocyclic purple dye prepared in the present application has the AIE characteristic of coupling triphenylamine groups and tetraphenylstyrene groups to a boron-nitrogen heterocyclic compound, and has a certain light-heat conversion ability through testing.

[0020] Meanwhile, the synthetic route proposed by the present application needs to react the morpholine group of the boron-nitrogen heterocyclic compound with 1-(4-phenylboronic acid pinacol ester)-1,2,2-triphenylstyrene first, and then with 4-ethynyltriphenylamine, so as to obtain the target dye with high yield. If it is reversed, it will result in extremely low yield of the target product. Considering the influence of the interaction between functional groups on the reaction, and the compatibility of the reaction conditions, the present application adjusts the synthetic route, first tries to introduce the tetraphenylstyrene group on one side, and then connects the triphenylamine group on the other side, and at the same time makes slight adjustment to the reaction conditions, so that the total yield is significantly improved. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is the HRMS graph of the boron-nitrogen heterocyclic purple dye Z prepared in Example 1. 1 H NMR chart.

[0022] Figure 2 is the HRMS graph of the boron-nitrogen heterocyclic purple dye Z prepared in Example 1. 13 C NMR chart

[0023] Figure 3 is the HRMS graph of the boron-nitrogen heterocyclic purple dye Z prepared in Example 1.

[0024] Figure 4 is the chart of the fluorescence of the boron-nitrogen heterocyclic purple dye Z prepared in Example 1 in a mixed solvent of water and DMF, which changes with different water fractions (fw).

[0025] Figure 5 is the temperature rising curve chart of the boron-nitrogen heterocyclic purple dye Z prepared in Example 1 under different concentration conditions, which rises with laser irradiation.

[0026] Figure 6 is the temperature rising curve chart of the boron-nitrogen heterocyclic purple dye Z prepared in Example 1 under different light power density laser irradiation. DETAILED DESCRIPTION

[0027] The present application will be further described in detail below in combination with examples and drawings.

[0028] Comparative Example 1

[0029] Step a, synthesis of compound 2:

[0030]

[0031] Compound 1 (9.8 mmol) was dissolved in a 25 mL round-bottom flask containing 8 mL CHCl3and 4 mL CH3COOH, and the reaction was allowed to proceed at room temperature for 0.5 h. The reaction progress was monitored by TLC. After the reaction was completed, the CH3COOH was removed, and the organic phase was combined and dried over anhydrous Na2SO4for 1 h. The organic solvent was removed under reduced pressure, and the residue was redissolved in CH2Cl2. The product was separated by silica gel column chromatography using EA / PE (v / v = 1 / 1) as the eluent. Compound 2 was obtained in a yield of 40%.

[0032] Step b1, synthesis of compound 4a:

[0033]

[0034] Compound 2 (0.16 mmol) and starting material 6 (0.42 mmol) were dissolved in a mixture of toluene / triethylamine (v / v = 5 / 1) in a three-necked flask. Nitrogen was continuously bubbled into the reaction at room temperature for 30 min to remove oxygen. After the reaction was completed, 0.27 mmol of PPh3and 0.08 mmol of Pd2(dba)3were quickly added, and the reaction was sealed. The reaction was transferred to a 60 °C oil bath for further reaction. The reaction was monitored by TLC until the starting material was completely consumed. The reaction was stopped, and the organic solvent was removed under reduced pressure. The residue was redissolved in CH2Cl2. The product was separated by column chromatography using EA / CH2Cl2(v / v = 1 / 1) as the eluent. The final compound 4a was obtained in a yield of 71%. HRMS (MALDI-TOF) m / z calcd for C 49 H 51 BF2N4O2[M +· ]776.4075, found: 776.4078.

[0035] Step c1, synthesis of compound 5a:

[0036]

[0037] Dissolve 0.25 mmol of compound 4a and 0.28 mmol of NIS in 12 mL of a mixed solvent of CHCl3 / CH3COOH (v / v = 2 / 1) in a 25 mL round-bottom flask, and seal it in a 60 ℃ oil bath for about 45 min. Monitor the reaction progress by TLC. After the reaction is completed, cool it to room temperature, extract it with saturated aqueous sodium thiosulfate and CH2Cl2three times, remove CH3COOH, combine the organic phase, and add anhydrous Na2SO4to dry it for 1 h. Remove the organic solvent by distillation under reduced pressure, and redissolve it in CH2Cl2. Separate it by silica gel column chromatography using CH2Cl2 / EA (v / v = 4 / 1) as the eluent to obtain compound 5a with a yield of 35%. HRMS (MALDI-TOF) m / z calcd for C 49 H 50 IBF2N4O2[M +· ] 903.3040, found:903.3046.

[0038] Step d1, synthesis of compound Z:

[0039]

[0040] Dissolve 0.055 mmol of compound 5a, 0.055 mmol of raw material 3, and 0.073 mmol of K2CO3 in a three-necked flask, then add 23 mL of a mixed solvent of THF / H2O (v / v = 20 / 3) to the flask and ultrasonically treat it. Then, introduce nitrogen into the flask for 30 min to remove internal oxygen, then quickly add 0.005 mmol of Pd(PPh3)4, seal the flask, and place it in a 70 ℃ oil bath for 12-24 h. Monitor the reaction progress by TLC, and show it by spotting. A large amount of by-product appears during the reaction, and until the reaction stops, the raw material is consumed, and there is still no obvious product spot, so it is impossible to determine the existence of target product Z.

[0041] Based on the reaction results of Comparative Example 1, the following possible reasons for experimental failure are summarized:

[0042] 1. Both triphenylamine and tetraphenylstyryl have a large steric volume, which may affect the active site on the other side through steric hindrance, and the intermediate boron-nitrogen heterocyclic compound itself is a planar rigid molecule, and the crowding of the two substituents further aggravates the steric conflict.

[0043] 2. Triphenylamine is easy to oxidize, and the Pd catalyst may coordinate with the N atom of triphenylamine, reducing the catalytic effect.

[0044] According to the above speculation, the reaction route was adjusted: the tetraphenylstyryl group, which can freely rotate the benzene ring to adjust the conformation, was first introduced to one side of the molecule, and the triphenylamine group on the other side was adjusted to avoid serious collision, and the first step of introducing the tetraphenylstyryl group avoided the sensitivity of the triphenylamine group to the reaction conditions and produced numerous by-products.

[0045] The following is the adjusted synthesis route.

[0046] Example 1

[0047] Step a, synthesis of compound 2:

[0048]

[0049] Dissolve 9.8 mmol of compound 1 and 7.8 mmol of NIS in a 25 mL round-bottom flask containing 8 mL of CHCl3 and 4 mL of CH3COOH, and react at room temperature for 0.5 h. Monitor the reaction progress by TLC. When the reaction is complete, extract with saturated aqueous sodium thiosulfate and CH2Cl2 three times, remove CH3COOH, combine the organic phases and add anhydrous Na2SO4 and dry for 1 h. Remove the organic solvent under reduced pressure and redissolve in CH2Cl2. Separate by silica gel column chromatography using EA / PE (v / v = 1 / 1) as eluent to obtain compound 2 with a yield of 40%.

[0050] Synthesis of compound 2 1 H NMR (400 MHz, CDCl3) δ 7.16-7.12 (m, 2H), 7.01-6.97 (m, 2H), 6.03-5.97 (m, 1H), 4.02-3.98 (m, 2H), 3.73 (t, J = 4.4 Hz, 4H), 2.62 (s, 3H), 2.55 (d, J = 4.4 Hz, 4H), 2.45 (s, 3H), 2.36 (t, J = 7.6 Hz, 2H), 1.87-1.78 (m, 4H), 1.59-1.49 (m, 4H), 1.43 (s, 6H). HRMS (MALDI-TOF) m / z calcd for C 29 H 37 IBF2N3O2[M +· ] 635.1992, found: 635.1995.

[0051] Step b2, synthesis of compound 4b:

[0052]

[0053] Into a three-necked flask, 0.15 mmol of compound 2, 0.18 mmol of compound 3 and 0.225 mmol of K2CO3 were added, then 23 mL of THF / H2O (v / v = 20 / 3) mixed solvent was added into the flask and sonicated. Then, the flask was purged with nitrogen for 30 min to remove the internal oxygen, and then 0.015 mmol of Pd(PPh3)4 was quickly added, the flask was sealed and placed in an oil bath at 70 °C for about 7 h. The reaction progress was monitored by TLC until the complete reaction of the raw material. After the reaction was completed, it was cooled to room temperature, extracted with water and CH2Cl2 three times, the organic phase was combined and dried with anhydrous Na2SO4 for 1 h. The solvent was removed under reduced pressure, and then the product was redissolved with CH2Cl2. Compound 4b was obtained by silica gel column chromatography with EA / PE (v / v = 1 / 3) as eluent, with a yield of 69%.

[0054] Synthesis of compound 4b 1 H NMR (400 MHz, CDCl3) δ 7.17 (d, J = 7.6 Hz, 2H), 7.10-7.00 (m, 19H), 6.86 (d, J = 7.2 Hz, 2H), 5.99 (s, 1H), 4.00 (t, J = 6.0 Hz,2H), 3.73 (s, 4H), 2.56 (s, 4H), 2.46 (s, 6H), 2.36 (t, J = 7.2 Hz, 2H),1.83-1.82 (m, 2H),1.54 - 1.53 (m, 6H), 1.43 (s, 3H), 1.30 (s, 3H). HRMS (MALDI-TOF) m / z calcd for C 55 H 56 BF2N3O2[M +· ] 839.4437, found: 839.4445.

[0055] Step c2, synthesis of compound 5b:

[0056]

[0057] Into a single-necked round-bottom flask, 0.06 mmol of compound 4b and 0.047 mmol of NIS were added, 8 mL of CHCl3and 4 mL of CH3COOH were added, and the solids were dissolved by ultrasonic. The reaction was carried out at room temperature for 1.5 h, and the progress of the reaction was monitored by TLC. After the reaction was completed, the reaction mixture was extracted with CH2Cl2for three times, and the CH3COOH was removed. The organic phase was combined and dried over anhydrous Na2SO4for 1 h. The organic solvent was removed under reduced pressure, and redissolved in CH2Cl2. Compound 5b was obtained by silica gel column chromatography using EA / PE (v / v = 1 / 2) as eluent, with a yield of 77%.

[0058] Synthesis of compound 5b 1 H NMR (400 MHz, CDCl3) δ 7.15 (d, J = 8.4 Hz, 2H), 7.12 -6.99 (m, 19H), 6.85 (d, J = 8.0 Hz, 2H), 4.01 (t, J = 6.4 Hz, 2H), 3.73 (t, J= 4.4 Hz, 4H), 2.64 (s, 4H), 2.47 (s, 6H), 2.36 (t, J = 7.2 Hz, 2H), 1.88-1.81 (m, 4H), 1.58-1.51 (m, 4H), 1.44 (s, 3H), 1.31 (s, 3H). HRMS (MALDI-TOF)m / z calcd for C 55 H 55 IBF2N3O2[M +· ] 965.3400, found: 965.3396.

[0059] Step d2, synthesis of compound Z:

[0060]

[0061] Compound 5b and 0.08 mmol of compound 6 were placed in a three-necked round bottom flask, and toluene / triethylamine (v / v = 1 / 1) mixed solvent was added. After ultrasonic dissolution, nitrogen was continuously passed for 30 min to remove oxygen in the reaction. After completion, 0.05 mmol of triphenylphosphine and 0.016 mmol of Pd2(dba)3 were quickly added, the reaction was sealed and placed in an 80 °C oil bath for about 100 min. The progress of the reaction was monitored by TLC until all the starting materials were completely reacted. After the reaction was completed, the reaction mixture was cooled to room temperature, and the solvent was removed by a rotary evaporator. Subsequently, the dried residue was redissolved using CH2Cl2. Compound Z was obtained by silica gel column chromatography using EA / PE (v / v = 1 / 3) as eluent, with a yield of 43%.

[0062] The target product Z was prepared according to the following reaction scheme: 1 H NMR, 13 C NMR and HRMS are shown in FIGS. 1-3, respectively, and the spectrum analysis is as follows: Figure 1 、 2 and 3, respectively, and the spectrum analysis is as follows:

[0063] 1 H NMR (400 MHz, CDCl3) δ 7.31 (s, 1H), 7.29 (d, J = 4 Hz, 2H), 7.24(s, 2H), 7.17 (d, J = 8.4 Hz, 2H), 7.12-7.09 (m, 10H), 7.08-7.03 (m, 10H),7.02-7.00 (m, 4H), 7.00-6.97 (m, 4H), 6.86 (d, J = 8.0 Hz, 2H), 4.01 (t, J =6.4 Hz, 2H), 3.73 (t, J = 4.4 Hz, 4H), 2.69 (s, 2H), 2.48 (s, 6H), 2.37 (t, J= 7.2 Hz, 2H), 1.86-1.82 (m, 2H), 1.55 (s, 6H), 1.42 (dd, J = 14.4 Hz, 7.6Hz, 2H), 1.26 (s, 6H).

[0064] 13C NMR (100 MHz, CDCl3) δ 167.92, 159.88, 156.69, 156.05, 147.80, 147.34, 143.76, 143.66, 143.54, 142.80, 142.52, 142.28, 141.49, 140.72, 140.34, 132.57, 132.36, 131.46, 131.36, 131.03, 129.50, 129.41, 129.35, 128.94, 127.83, 127.78, 127.66, 126.61, 124.97, 123.58, 122.65, 122.41, 115.28, 96.25, 81.27, 68.30, 58.65, 53.06, 38.86, 29.83, 29.06, 25.99, 23.12, 14.19, 13.62, 13.25, 11.10.

[0065] HRMS (MALDI-TOF) m / z calcd for C 75 H 69 BF2N4O2[M +· ] 1106.5488, found:1106.5478.

[0066] Example 3

[0067] The following takes boron-nitrogen heterocyclic purple dye Z as an example to study the application in aggregation-induced emission and photo-thermal conversion.

[0068] In order to explore the photophysical properties of Z, the fluorescence intensity of compound Z in DMF / H2O mixed solvent with different water fractions (fw) was tested. The specific steps are as follows: the sample Z to be tested is configured into a solution with a concentration of 1 × 10 -3 mol / L using DMF as the solvent; 10 portions of DMF / H2O mixed solvents are prepared, each portion of the mixed solvent has a volume of 2 mL, and the water content in each portion of the mixed solvent is 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, and 99%, respectively, and another 2 mL of DMF solvent is prepared separately as a solvent with a water fraction (fw) of 0%; in each portion of the mixed solvent, 20 μL of the sample solution is added, and after mixing uniformly, it is transferred to a 10 mm*10 mm four-transmission quartz cuvette; the fluorescence spectrophotometer is used to record the fluorescence change under the excitation wavelength of 490 nm. The results are shown in FIG. 2. Figure 4

[0069] As shown in FIG. 2. Figure 4 ​It can be seen that the fluorescence gradually increases with the increase of water content (fw) (from 0% to 70%). When the water content exceeds 70%, the fluorescence weakens again. This is mainly because at this solvent ratio, the molecules become aggregates, restricting intramolecular movement and exhibiting typical AIE characteristics.

[0070] To verify the photothermal conversion performance of compound Z, its temperature changes at different concentrations and optical power densities were measured. The specific procedures were as follows: F127 was added to the sample and dissolved by ultrasonication with CH2Cl2. The CH2Cl2 was removed under reduced pressure, and a measured amount of water was added to prepare a 300 μM sample solution for dilution. The solution was stirred overnight to form nanoparticles. The stirred nanoparticle solution was then diluted with water to prepare 25, 50, 75, 100, 150, 200, and 250 μM solutions, respectively, and brought to a final volume of 0.5 mL. Similarly, 0.5 mL of the 300 μM solution was prepared. A 660 nm laser with a power density of 1.5 W / cm² was used. 2 The optical power density was measured, and the sample was irradiated for 10 minutes, with data recorded every 30 seconds using a thermal imager. A 200 μM sample was prepared, divided into six 0.5 mL aliquots, and irradiated using a 660 nm laser at power densities of 0.25, 0.5, 0.75, 1.0, 1.25, and 1.5 W / cm², respectively. 2 The light power density was used to irradiate the sample for 10 minutes, and data was recorded every 30 seconds using a thermal imager. The results are attached. Figure 5 , 6 As shown.

[0071] From the appendix Figure 5 and 6 It can be seen that the temperature gradually increases with the increase of sample concentration and optical power density, with the highest temperature approaching 60 ℃, indicating that it has good photothermal conversion performance and a photothermal conversion efficiency of 16.2%.

Claims

1. A method for synthesizing a boron-nitrogen heterocyclic violet dye, characterized in that, The synthetic route is as follows: The steps are as follows: Step a: Dissolve compound 1 and NIS in an organic solvent to react and generate compound 2. In this reaction, the molar ratio of compound 1 to NIS is 0.9:0.7~0.

8. The reaction is carried out at room temperature for 0.5 h. Step b: Compound 2, raw material 3, and K2CO3 are dissolved in an organic solvent, and compound 4 is synthesized under the catalysis of Pd(PPh3)4. The molar ratio of compound 2, raw material 3, K2CO3, and Pd(PPh3)4 is 0.9:1.2~1.5:1.5~1.8:0.10~0.12, the reaction temperature is 70~80 ℃, and the reaction time is 6~11 h. Step c: Dissolve compound 4 and NIS in an organic solvent to react and generate compound 5. In this reaction, the molar ratio of compound 4 to NIS is 0.9:0.5~1.

0. The reaction is carried out at room temperature for 1.5 h. Step d: Dissolve compound 5, raw material 6, PPh3, and Pd2(dba)3 in an organic solvent to react and generate compound Z. The molar ratio of compound 5, raw material 6, PPh3, and Pd2(dba)3 is 0.9:2.5~2.7:1.6~1.8:0.5~0.

6. The reaction temperature is 80~90 °C and the reaction time is 1.5~2.5 h.

2. The synthesis method according to claim 1, characterized in that, The specific operation of step a is as follows: Compound 1 is mixed with NIS in a single-necked round-bottom flask, and a mixed solvent of CHCl3 / CH3COOH (v / v = 2 / 1) is added. After ultrasonic dissolution, the mixture is reacted at room temperature, and the reaction process is monitored using TLC. When the TLC shows that the raw materials have been consumed, the reaction is stopped. The reaction is extracted with saturated sodium thiosulfate aqueous solution and CH2Cl2 to remove CH3COOH. After three extractions, the organic phases are combined, and anhydrous Na2SO4 is added for drying to remove moisture. The solvent is removed by vacuum distillation to obtain the crude product, which is then separated by column chromatography to obtain compound 2.

3. The synthesis method as described in claim 2, characterized in that, The specific operation of step b is as follows: Compound 2, raw material 3, and K2CO3 are ultrasonically dissolved in a mixed solvent of freshly distilled tetrahydrofuran and water (v / v = 20 / 3) and placed in a three-necked round-bottom flask; nitrogen gas is continuously purged at room temperature for 30 min to remove oxygen in the reaction, and Pd(PPh3)4 is quickly added as a catalyst after the reaction is completed and the reaction is sealed; the reaction is carried out in a 70 °C oil bath and monitored by TLC until the raw material disappears and the reaction is stopped; after cooling to room temperature, the mixture is repeatedly extracted with water and CH2Cl2, the organic phases are combined, and anhydrous Na2SO4 is added for drying; the organic solvent is removed by rotary evaporation to obtain the crude product, which is then separated and purified by column chromatography to obtain compound 4.

4. The synthesis method as described in claim 3, characterized in that, The specific operation of step c is as follows: Compound 4 is mixed with NIS in a single-necked round-bottom flask, and a mixed solvent of CHCl3 / CH3COOH (v / v = 2 / 1) is added. After ultrasonic dissolution, the mixture is reacted at room temperature, and the reaction process is monitored using TLC. When the TLC shows that the raw materials have been consumed, the reaction is stopped. CH3COOH is removed by extraction with saturated sodium thiosulfate aqueous solution and CH2Cl2. The extraction is repeated multiple times, and the organic phases are combined. Anhydrous Na2SO4 is added for drying to remove water. The solvent is removed by vacuum distillation to obtain the crude product, which is then separated by column chromatography to obtain compound 5.

5. The synthesis method as described in claim 4, characterized in that, The specific operation of step d is as follows: Compound 5 and raw material 6 are mixed and added to a three-necked round-bottom flask, and a mixed solvent of toluene / triethylamine (v / v = 1 / 1) is added. The mixture is then sonicated to dissolve the compounds. Nitrogen gas is continuously purged at room temperature for 30 min to remove oxygen from the reaction. After the reaction is complete, PPh3 and Pd2(dba)3 are quickly added and the reaction is sealed. The reaction is then transferred to an 80 °C oil bath and the reaction continues. The reaction is monitored by TLC until the raw material is completely eliminated, at which point the reaction is stopped. After cooling to room temperature, the mixture is extracted with water and CH2Cl2. After multiple extractions, the organic phases are combined and dried with anhydrous Na2SO4. The organic solvent is then removed under reduced pressure, and the mixture is separated by column chromatography to obtain the final compound Z.

6. A boron-nitrogen heterocyclic violet dye synthesized by the method according to any one of claims 1 to 5.

7. The application of the boron-nitrogen heterocyclic violet dye as described in claim 6 in aggregation-induced emission and photothermal conversion.

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