Luminescent material based on BODIPY and preparation method and application thereof

Abstract

The invention relates to the technical field of organic materials, and particularly discloses a BODIPY-based luminescent material as well as a preparation method and application thereof. The benzofuran condensed BODIPY oligomer is synthesized for the first time by adopting a synergistic strategy of an intermolecular nucleophilic aromatic substitution reaction and a C-H coupling reaction. According to the present invention, the combination of the benzofuran condensation unit and the BODIPY subunit is introduced, and the heteroatom is introduced, such that the optical performance based on the BODIPY dye molecule is significantly provided, the new strategy is provided for the design of the new generation of the near-infrared fluorescent dye molecule, and the theoretical basis is provided for the precise control of the energy level regulation in the large pi conjugated system.

Description

Technical Field

[0001] This invention relates to the field of organic light-emitting materials technology, and in particular to a BODIPY-based light-emitting material, its preparation method, and its application. Background Technology

[0002] As a core component of next-generation optoelectronic functional materials, large π-conjugated systems have shown remarkable application prospects in cutting-edge fields such as semiconductor devices, molecular wires, and near-infrared absorbers. The unique electronic delocalization properties of these systems enable them to effectively regulate photophysical processes. Therefore, the study of luminescent molecules based on large π-conjugated systems has become one of the most dynamic research directions in the field of organic functional materials. However, traditional large π-conjugated systems face two main challenges: (1) overly complicated synthetic routes, with problems such as low yield, poor solubility, and fluorescence quenching and decreased photostability due to rigid planar conformations; (2) achieving the extension of absorption and emission wavelengths into the near-infrared region while maintaining high luminescence efficiency. These challenges and the unexplored material properties indicate an urgent need to develop efficient and controllable synthetic methods to construct novel large π-conjugated molecules with diverse structures and tunable properties.

[0003] Borylobar dipyrrole (BODIPY) dyes, with pyrrole and BF2 groups as their core structure, allow for significant modulation of the photoelectric properties of the entire system by modifying the pyrrole ring with different substituents. They possess advantages such as high luminous efficiency, tunable photoelectric properties, excellent solubility, and stability, making them a popular candidate material for constructing large π-conjugated systems. In recent years, various conformationally restricted BODIPY oligomers have been developed from BODIPY fused molecular systems with large π-conjugated structures, successfully enabling precise modulation of photoelectronic properties to the NIR band. These oligomers can be applied in near-infrared absorbing dyes, thermally activated delayed fluorescence materials, photodynamic therapy, and OLEDs.

[0004] Although existing technologies have reported improving the luminescence efficiency of BODIPY molecules by introducing heteroatoms (S, N, O) to regulate their photoelectric properties, existing BODIPY oligomers still suffer from low luminescence efficiency, significant difficulties in preparation and purification, and unclear microscopic structures and performance regulation mechanisms of the heteroatom-rich π-conjugated system.

[0005] Therefore, designing a large π-conjugated heteroatom-fused BODIPY luminescent molecule with a simple preparation method, high luminescence efficiency, and a well-defined performance regulation mechanism is of great significance for the study of luminescent molecules in large π-conjugated systems. Summary of the Invention

[0006] In view of this, the present invention provides a BODIPY-based luminescent material, its preparation method and application, which solves the problems of complex preparation, low luminescence efficiency and unclear performance regulation mechanism of BODIPY luminescent molecules with large π-conjugated heteroatoms in the prior art.

[0007] To solve the above-mentioned technical problems, the technical solution provided by the present invention is as follows: The first aspect of this invention provides a BODIPY-based luminescent material, the structural formula of which includes any one of Formulas 1-4: , , or Formula I; Formula II; Formula III

[0008] Formula IV.

[0009] A second aspect of the present invention provides a method for preparing a BODIPY-based luminescent material, wherein if the BODIPY-based luminescent material is a compound represented by Formula I, Formula II, or Formula III, the method includes the following steps: Step 1: Under an inert atmosphere, the first compound and the second compound are mixed evenly and dissolved in a low-boiling-point organic solvent. A basic catalyst is added, and a substitution reaction is carried out at 75-85℃ to obtain the third compound. Step 2: Under an inert atmosphere, the third compound is dissolved in an organic solvent, and an organic palladium catalyst, 1,1'-binaphthyl-2,2'-bis(diphenylphosphine) and cesium carbonate are added and mixed evenly. A cyclization reaction is carried out at 110-120°C to obtain a luminescent material based on BODIPY. The first compound is or Any one of them; The second compound is or Any one of them; The third compound is , or Any one of them.

[0010] Preferably, in step one, the first compound is prepared according to prior art 1 (He,L.;Li,L.;Zhao,M.;Zhao,Y.;Li,Y.;Li,X.;Yang,Y.;Gao,S.;Lei,P.;Wang,Z.;Jiang,W. Dibenzothieno anddibenzothieno[2,3-d]thieno [a]-fused BODIPYs: synthesis, unique structure and photophysical properties, Mater. Chem. Front., 2024, 8, 3266-3271.) or prior art 2 (Guan, H.;Yang, R.;He, L.;Li, X.;Cao, Y.;Gao, S.;Li, Y.;Yang, Y.;Li, X. Oxa-phenalene [b]-fused BODIPY dyes: synthesis, structures, and photophysicalproperties, Tetrahedron, 2025, Synthesized using the method described in 183, 134728.

[0011] Preferably, in step one, the molar ratio of the first compound to the second compound is 1:1 to 1:2.

[0012] Preferably, in step one, the low-boiling-point organic solvent is acetonitrile.

[0013] Preferably, in step one, the basic catalyst is potassium carbonate.

[0014] Preferably, the mass-to-volume ratio of the first compound to the low-boiling-point organic solvent is 0.005 g: 1 mL to 0.02 g: 1 mL.

[0015] Preferably, the molar ratio of the first compound to the basic catalyst is 1:2 to 1:2.2.

[0016] Preferably, in step one, the substitution reaction takes 30-50 minutes.

[0017] Preferably, in step two, the organic solvent is anhydrous toluene.

[0018] Preferably, in step two, the mass-to-volume ratio of the third compound to the organic solvent is 0.005 g: 1 mL to 0.02 g: 1 mL.

[0019] Preferably, in step two, the molar ratio of the third compound to the organopalladium catalyst, 1,1'-binaphthyl-2,2'-bis(diphenylphosphine) and cesium carbonate is 1:0.1-0.12:0.2:2.

[0020] Preferably, in step two, the cyclization reaction takes 12-14 hours.

[0021] A third aspect of the present invention provides a method for preparing a BODIPY-based luminescent material, wherein when the structural formula of the BODIPY-based luminescent material is as described in Formula IV of claim 1, the method includes the following steps: S1. In an inert atmosphere, and After being mixed evenly, the mixture was dissolved in acetonitrile, potassium carbonate was added, and a substitution reaction was carried out at 75-85℃ to obtain the fourth compound. S2. Under an inert atmosphere, the fourth compound and Dissolved in acetonitrile, potassium carbonate was added, and a substitution reaction was carried out at 75-85℃ to give the fifth compound; S3. Dissolve the fifth compound in an organic solvent, add an organopalladium catalyst, 1,1'-binaphthyl-2,2'-bis(diphenylphosphine) and cesium carbonate, mix thoroughly, and carry out a cyclization reaction at 110-120°C to obtain the BODIPY-based luminescent material; wherein, in S1, the structure of the fourth compound is as follows: ; In S2, the structure of the fifth compound is as follows: Preferably, the substitution reaction time in S1 or S2 is 30-50 min.

[0022] Preferably, in S1, the The mass-to-volume ratio of the acetonitrile to the acetonitrile is 0.005 g: 1 mL to 0.02 g: 1 mL.

[0023] Preferably, in S2, the mass-to-volume ratio of the fourth compound to the acetonitrile is 0.005 g: 1 mL to 0.01 g: 1 mL.

[0024] Preferably, in S3, the mass-to-volume ratio of the fifth compound to the organic solvent is 0.005 g:1 mL to 0.01 g:1 mL.

[0025] Preferably, in S3, the molar ratio of the fifth compound, the organopalladium catalyst, 1,1'-binaphthyl-2,2'-bis(diphenylphosphine) and cesium carbonate is 1:0.1-0.12:0.2:2.

[0026] Preferably, in S3, the cyclization reaction takes 12-14 hours.

[0027] The fourth aspect of this invention provides the application of the aforementioned BODIPY-based luminescent material in the preparation of near-infrared fluorescent dyes.

[0028] Beneficial effects: This invention utilizes halogenated BODIPY precursors and a synergistic strategy combining intermolecular nucleophilic aromatic substitution and CH coupling reactions to successfully and efficiently synthesize various BODIPY fused polymers with precise structures, including monofused polymers (BFB-mono), bisfused polymers (bis-BFB), and large π-conjugated benzofuran-fused BODIPY oligomers (BFB-di, BFB-tri). These fused polymers with large π-conjugated systems exhibit a significant spectral redshift effect, with their absorption peak shifting from 503 nm in the conventional BODIPY molecule to 716 nm in BFB-tri (in toluene solution). This phenomenon indicates their excellent absorption characteristics in the near-infrared region, demonstrating their potential application value as strong near-infrared absorbing dyes. In particular, the benzofuran-fused BODIPY trimer BFB-tri exhibits an extremely high molar absorptivity, reaching 400,000 M. -1 cm -1 Furthermore, the fluorescence quantum yield ΦF in toluene solution is as high as 69.8%, exhibiting strong fluorescence properties.

[0029] Furthermore, the structural insertion of the fused body provided by this invention has a significant modulating effect on the HOMO energy level, while the LUMO energy level is mainly affected by the number of BODIPY subunits. With the increase of the number of BODIPY subunits and the fused body, the LUMO energy level decreases, and the HOMO energy level increases, thus effectively narrowing the HOMO-LUMO band gap. This conclusion was verified by cyclic voltammetry (CV) measurements and theoretical calculations. This invention not only successfully achieved the precise and controllable construction of heteroatom-doped fused-ring π-systems, but also revealed the precise modulation mechanism of HOMO and LUMO energy levels in large π-conjugated systems, providing a novel approach and strategy for the design of next-generation near-infrared fluorescent dye molecules. It effectively overcomes the shortcomings of existing technologies. Attached Figure Description

[0030] Figure 1 X-ray structure diagrams of the BODIPY-based luminescent materials obtained in Examples 3 and 4 are shown; wherein, Figure 1 a is a front view of the X-ray structure of the BODIPY-based luminescent material obtained in Example 3; Figure 1 b is a side view of the BODIPY-based luminescent material obtained in Example 3; Figure 1 c is a front view of the X-ray structure of the BODIPY-based luminescent material obtained in Example 4; Figure 1 d is a side view of the BODIPY-based luminescent material obtained in Example 4; Figure 2 The NICS(0) values, ACID plots, and ESP analysis plots of the BODIPY-based luminescent materials obtained in Examples 3 and 4 are shown below; Figure 2 a represents the NICS(0) value of the BODIPY-based luminescent material obtained in Examples 3 and 4; Figure 2 b is the anisotropy diagram of the induced current density of the NICS(0) values ​​of the BODIPY-based luminescent materials obtained in Examples 3 and 4; Figure 2 c is the ESP analysis diagram of the BODIPY-based luminescent materials obtained in Examples 3 and 4; Figure 3 The figures show the absorption spectrum, emission spectrum, energy level diagram, and calculated analysis diagram of the BODIPY-based luminescent material and meso-trimethylyl-BODIPY in dichloromethane obtained in Examples 1-4; among them, Figure 3 a is the absorption spectrum of the BODIPY-based luminescent material obtained in Examples 1-4 and meso-trimethylyl-BODIPY in dichloromethane; Figure 3 b shows the emission spectra of the BODIPY-based luminescent materials obtained in Examples 1-4 and meso-trimethylyl-BODIPY in dichloromethane; Figure 3 c is the energy level diagram of the BODIPY-based luminescent material and the monomer BODIPY in dichloromethane obtained in Examples 1-4; Figure 3 d is a calculation analysis graph of the BODIPY-based luminescent material obtained in Examples 1-4 and meso-trimethylyl-BODIPY in dichloromethane; Figure 4 The CV diagrams are of the BODIPY-based luminescent materials obtained in Examples 1-4 and meso-trimethylyl-BODIPY in dichloromethane. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0032] To better illustrate the present invention, further examples are provided below.

[0033] Example 1 This embodiment provides a BODIPY-based luminescent material BFB-mono, specifically including the following steps:

[0034] Compounds A (17.23 mg, 0.05 mmol, 1.0 eq), C (12.98 mg, 0.075 mmol, 1.5 eq), and K₂CO₃ (13.82 mg, 0.10 mmol, 2 eq) were added to a two-necked round-bottom flask containing 2.0 mL of dimethylacetamide. The reaction mixture was stirred at 80°C for 30 minutes. The organic phases were combined, evaporated under reduced pressure, dried over anhydrous Na₂SO₄, and purified by silica gel column chromatography (petroleum ether / dichloromethane = 8 / 1, v / v) to give compound 1, a green solid, in 70% yield, with a mass of 16.84 mg. 1 HNMR(400 MHz, CDCl3) δ 7.76 (s, 1H), 7.68 (dt, J = 7.9, 1.0 Hz, 1H), 7.42 – 7.36(m, 2H), 7.23 – 7.17 (m, 1H), 6.94 (s, 2H), 6.63 (d, J = 4.7 Hz, 1H), 6.49 (dd, J = 4.0, 1.2 Hz, 1H), 6.39 (dd, J = 4.0, 2.1 Hz, 1H), 5.58 (d, J = 4.7 Hz, 1H), 2.35 (s, 3H), 2.13 (s, 6H). 13 C NMR(101 MHz, CDCl3) δ 166.08, 151.27, 143.49,139.59, 138.82, 137.01, 134.44, 133.75, 133.06, 130.69, 129.59, 129.23,128.34, 128.24, 126.27, 123.10, 116.71, 115.89, 105.76, 21.36, 20.25. 19 F NMR (376 MHz, CDCl3) δ -147.83 (dd, J = 57.0, 27.8 Hz).HRMS(ESI-Orbitrap, [M] - (100%): calculated for C 24 H 20 ON2BBrF2,480.0815, found, 480.0821; Delta (ppm) =0.63.

[0035] Compound 1 (12.03 mg, 0.025 mmol, 1.0 eq), palladium acetate (Pd(OAc)2) (0.56 mg, 0.0025 mmol, 0.1 eq), 2'-bis(diphenylphosphine)-1,1'-binaphthyl (BINAP, 3.11 mg, 0.005 mmol, 0.2 eq), and cesium carbonate (Cs2CO3) (16.29 mg, 0.050 mmol, 2 eq) were added to a two-necked round-bottom flask containing 2.0 mL of toluene. The reaction mixture was stirred at 110°C for 12 hours under an argon atmosphere. After the reaction was complete, the mixture was cooled, the solution was poured into water, and the organic phase was extracted with dichloromethane. The combined organic phases were evaporated under reduced pressure, dried over anhydrous sodium sulfate, and purified by silica gel column chromatography (petroleum ether / dichloromethane = 10 / 1, v / v) to give 6.40 mg of compound BFB-mono in 64% yield as a green solid. 1 HNMR(400 MHz, CDCl3) δ 7.79 (s, 1H), 7.56 – 7.50 (m, 2H), 7.35 (ddd, J = 8.5,7.5, 1.5 Hz, 1H), 7.29 – 7.26 (m, 1H), 6.98 (s, 2H), 6.71 (s, 1H), 6.56 –6.51 (m, 1H), 6.43 (dd, J = 4.1, 2.0 Hz, 1H), 2.38 (s, 3H), 2.16 (s, 6H). 13 C NMR(101 MHz, CDCl3) δ 169.59, 161.72, 146.14, 140.55, 139.10, 137.03, 136.09,134.54, 129.66, 128.46, 127.74, 127.32, 125.13, 122.34, 121.16, 120.42,119.64, 117.35, 113.37, 21.40, 20.23. 19 F NMR (376 MHz, CDCl3) δ -147.22 (dd, J =56.1, 27.7 Hz).HRMS(ESI-Orbitrap, [M] + (, 100%): calculated for C 24 H 19 ON2BF2,400.1553, found, 400.1544; Delta (ppm) = -0.85. Example 2 This embodiment provides a BODIPY-based luminescent material bis-BFB, specifically including the following steps:

[0036] Compounds A (18.95 mg, 0.05 mmol, 1.0 eq), C (21.62 mg, 0.125 mmol, 2.5 eq), and K₂CO₃ (13.82 mg, 0.10 mmol, 2 eq) were added to a two-necked round-bottom flask containing 2.0 mL of acetonitrile. The reaction was stirred at 80 °C for 30 min. The product was purified by silica gel column chromatography (eluent: petroleum ether / dichloromethane = 8 / 1, v / v) to give crude product 2, a yellow solid of 24.46 mg, in 75% yield. 1 H NMR(400 MHz, CDCl3) δ 7.68 – 7.61 (m, 2H),7.35 (dd, J = 6.8, 1.6 Hz, 4H), 7.14 (ddd, J = 8.1, 6.6, 2.3 Hz, 2H), 6.93 (s,2H), 6.45 (d, J = 4.3 Hz, 2H), 5.51 (d, J = 4.4 Hz, 2H), 2.34 (s, 3H), 2.16 (s, 6H). 13 C NMR(101 MHz, CDCl3) δ 163.17, 151.94, 141.14, 138.69, 137.40, 134.30,129.23, 129.17, 129.02, 128.70, 128.30, 127.53, 122.76, 115.75, 102.93,21.35, 20.26. 19 F NMR(376 MHz, CDCl3) δ -148.73, -148.80, -148.88, -148.95.HRMS(ESI-Orbitrap, [M] + (, 100%): calculated for C 30 H 23 O2N2BBr 81 BrF2, 652.0161, found, 652.0153; Delta (ppm) = -0.89.

[0037] Compound 2 (16.30 mg, 0.025 mmol, 1.0 eq), Pd(OAc)2 (0.56 mg, 0.0025 mmol, 0.1 eq), BINAP (3.11 mg, 0.005 mmol, 0.2 eq), and Cs2CO3 (16.29 mg, 0.050 mmol, 2 eq) were added to a two-necked round-bottom flask containing 2.0 mL of toluene. The reaction was stirred at 110 °C for 24 hours. The product was purified by silica gel column chromatography (eluent: petroleum ether / dichloromethane = 8 / 1, v / v) to give a green solid crude bis-BFB in 58% yield (7.11 mg). 1 H NMR (400 MHz, CDCl3) δ 7.56 – 7.49 (m, 4H), 7.32 (td, J = 7.8, 1.5 Hz,2H), 7.27 – 7.22 (m, 2H), 7.01 (s, 2H), 6.62 (s, 2H), 2.40 (s, 3H), 2.22 (s,6H). 13 C NMR(101 MHz, CDCl3) δ 167.49, 161.16, 145.30, 139.20, 137.39, 134.70,129.21, 128.51, 126.77, 124.78, 121.74, 121.62, 118.39, 117.27, 113.23,21.42, 20.19. 19 F NMR (376 MHz, CDCl3) δ -148.56 (dd, J = 54.6, 27.0 Hz).HRMS(ESI-Orbitrap, [M] + (, 100%): calculated for C 30 H 21 O2N2BF2, 490.1659, found, 490.1652;Delta (ppm) = -0.64. Example 3 This embodiment provides a BODIPY-based luminescent material BFB-di, specifically including the following steps:

[0038] Compounds A (17.23 mg, 0.05 mmol, 1.0 eq), D (5.35 mg, 0.10 mmol, 0.02 eq), and K₂CO₃ (13.82 mg, 0.10 mmol, 2 eq) were added to a two-necked round-bottom flask containing 2.0 mL of acetonitrile. The reaction was stirred at 80 °C for 1 hour. The product was purified by silica gel column chromatography (eluent: petroleum ether / dichloromethane = 5 / 1, v / v) to give crude product 3 as 13.62 mg of yellow solid, in 77% yield. 1 H NMR(400 MHz, CDCl3) δ 7.80 (s, 2H), 7.71 (s,2H), 6.95 (s, 4H), 6.68 (d, J = 4.6 Hz, 2H), 6.56 (d, J = 3.8 Hz, 2H), 6.43 (dd, J = 4.0, 2.0 Hz, 2H), 5.66 (d, J = 4.6 Hz, 2H), 2.36 (s, 6H), 2.13 (s, 12H). 13 CNMR(101 MHz, CDCl3) δ 164.34, 149.82, 144.85, 141.08, 139.05, 136.95, 134.25,132.77, 130.48, 129.38, 128.43, 127.60, 127.55, 117.48, 115.36, 104.86,21.38, 20.25. 19 F NMR (376 MHz, CDCl3) δ -147.64 (dd, J = 56.2, 26.9 Hz).HRMS(ESI-Orbitrap, [M] + (, 100%): calculated for C 42 H 34 O2N4B2Br 81 BrF4, 884.1145, found, 884.1176; Delta (ppm) = 3.13.

[0039] Compound 3 (22.10 mg, 0.025 mmol, 1.0 eq), Pd(OAc)2 (0.56 mg, 0.0025 mmol, 0.1 eq), BINAP (3.11 mg, 0.005 mmol, 0.2 eq), and Cs2CO3 (16.29 mg, 0.050 mmol, 2 eq) were added to a two-necked round-bottom flask containing 2.0 mL of toluene. The reaction was stirred at 110 °C for 1 hour. The product was purified by silica gel column chromatography (eluent: petroleum ether / dichloromethane = 8 / 1, v / v) to give a dark brown solid crude product BFB-di in 82% yield (14.81 mg). 1 H NMR (400 MHz, CDCl3) δ 7.83 (s, 2H), 7.64 (s, 2H), 6.99 (s, 4H), 6.75 (s, 2H), 6.60 (dd, J = 4.1, 1.2 Hz, 2H), 6.46 (dd, J = 4.1, 2.0 Hz, 2H), 2.39 (s, 6H), 2.16 (s, 12H). 13 C NMR(101 MHz, CDCl3) δ 169.60, 158.53, 146.78,141.75, 139.29, 136.95, 136.06, 135.06, 129.41, 128.54, 128.28, 120.01,119.65, 119.17, 118.02, 106.44, 21.41, 20.24. 19 F NMR(376 MHz, CDCl3) δ -147.10(dd, J = 55.2, 24.8 Hz).HRMS(ESI-Orbitrap, [M] - (, 100%): calculated for C 42 H 32 O2N4B2F4, 722.2642, found, 722.2653; Delta (ppm) = 1.12. Example 4 This embodiment provides a BODIPY-based luminescent material BFB-tri, specifically including the following steps:

[0040] Compounds A (17.23 mg, 0.05 mmol, 1.0 eq), D (13.40 mg, 0.05 mmol, 1.0 eq), and K₂CO₃ (13.82 mg, 0.10 mmol, 2 eq) were added to a two-necked round-bottom flask containing 2.0 mL of acetonitrile. The reaction was stirred at 80 °C for 30 min. The product was purified by silica gel column chromatography (eluent: petroleum ether / dichloromethane = 2 / 1, v / v) to give crude yellow solid 4, with a yield of 23.33 mg (81%). 1 H NMR(400 MHz, CDCl3) δ 7.76 (s, 1H), 7.53 (s,1H), 7.34 (s, 1H), 6.94 (s, 2H), 6.64 (d, J = 4.7 Hz, 1H), 6.50 (dd, J = 3.9, 1.3Hz, 1H), 6.40 (dd, J = 4.0, 2.1 Hz, 1H), 5.69 (s, 1H), 5.60 (d, J = 4.6 Hz, 1H), 2.35 (s, 3H), 2.12 (s, 6H). 13 C NMR(101 MHz, CDCl3) δ 165.94, 151.77, 144.97,143.96, 140.05, 138.91, 137.01, 133.92, 133.01, 130.66, 129.53, 128.38,126.72, 125.94, 120.72, 116.97, 115.96, 109.19, 105.31, 21.37, 20.24. 19 F NMR (376 MHz, CDCl3) δ -147.64 (dd, J = 57.0, 27.7 Hz).HRMS(ESI-Orbitrap, [MH] - (100%): calculated for C 24 H 18 O2N2BBr 81 BrF2, 574.9770, found, 574.9776; Delta(ppm) = 0.58.

[0041] Compounds B (9.48 mg, 0.025 mmol, 1.0 eq), 4 (28.80 mg, 0.05 mmol, 2.0 eq), and K₂CO₃ (6.91 mg, 0.050 mmol, 2 eq) were added to a two-necked round-bottom flask containing 2.0 mL of acetonitrile. The reaction was stirred at 80 °C for 30 min. The product was purified by silica gel column chromatography (eluent: petroleum ether / dichloromethane = 2 / 1, v / v) to give crude yellow solid 5, in 55% yield, weighing 20.05 mg. 1 H NMR(400 MHz, CDCl3) δ 7.79 (s, 2H), 7.70 (s,2H), 7.68 (s, 2H), 6.95 (s, 6H), 6.67 (d, J = 4.6 Hz, 2H), 6.58 – 6.52 (m, 4H), 6.42 (dd, J = 4.0, 1.9 Hz, 2H), 5.66 (d, J = 4.6 Hz, 2H), 5.63 (d, J = 4.5 Hz, 2H), 2.35 (s, 9H), 2.16 (s, 6H), 2.13 (s, 12H). 13 C NMR (101 MHz, CDCl3) δ 164.59,162.14, 150.40, 149.35, 144.68, 142.91, 140.88, 139.09, 139.02, 137.25,136.96, 134.19, 132.83, 130.52, 129.98, 129.42, 129.07, 128.72, 128.47,128.42, 127.51, 127.42, 126.95, 117.37, 115.24, 115.04, 105.00, 103.32,21.38, 20.28, 20.25. 19 F NMR (376 MHz, CDCl3) δ -147.64 (dd, J = 55.8, 24.6 Hz), -148.55 (dd, J = 55.0, 27.1 Hz).HRMS(ESI-Orbitrap, [M] + (, 100%): calculated for C 66 H 51 O4N6B3Br2 81Br2F6, 1458.0842, found, 1458.0869; Delta (ppm) = 2.69.

[0042] Compound 5 (36.46 mg, 0.025 mmol, 1.0 eq), Pd(OAc)2 (0.56 mg, 0.0025 mmol, 0.1 eq), BINAP (3.11 mg, 0.005 mmol, 0.2 eq), and Cs2CO3 (16.29 mg, 0.050 mmol, 2 eq) were added to a two-necked round-bottom flask containing 2.0 mL of toluene. The reaction was stirred at 110 °C for 1 hour. The product was purified by silica gel column chromatography (eluent: petroleum ether / dichloromethane = 4 / 1, v / v) to give a dark brown crude product BFB-tri in 85% yield (24.11 mg). 1 H NMR (400 MHz, CD2Cl2) δ 7.77 (t, J = 1.6 Hz, 2H), 7.73 (s, 2H), 7.71 (s, 2H), 7.07 (s, 2H), 7.03 (s, 4H), 6.75 (s, 2H), 6.70 (s, 2H), 6.59(dd, J = 4.1, 1.2 Hz, 2H), 6.48 (dd, J = 4.0, 2.0 Hz, 2H), 2.42 (s, 3H), 2.39 (s,6H), 2.22 (s, 6H), 2.16 (s, 12H). 13 C NMR (101 MHz, CD2Cl2) δ 170.04, 168.38,158.84, 158.42, 146.72, 146.15, 141.08, 139.82, 139.52, 137.44, 137.08,136.41, 135.60, 135.07, 129.56, 128.88, 128.72, 128.59, 127.99, 120.64,120.32, 119.57, 119.48, 118.80, 117.94, 117.65, 106.60, 106.23, 21.35, 21.30, 20.05, 20.02. 19 F NMR (376 MHz, CD2Cl2) δ -146.96 (dd, J= 53.9, 22.3 Hz), -148.10(dd, J = 54.5, 26.7 Hz).HRMS(ESI-Orbitrap, [M] + (, 100%): calculated for C 66 H 47 O4N6B3F6, 1134.3837, found, 1134.3828; Delta (ppm) = -0.85. To further demonstrate the technical effectiveness of the dye molecules provided by this invention, the following tests were conducted: 1. Single crystal testing: The dye molecules obtained in Examples 3 and 4 were subjected to single-ray diffraction tests, and the results are as follows: Figure 1 As shown. From Figure 1 As can be seen, single-crystal X-ray diffraction further revealed the precise geometric configurations of the benzofuran-fused dimer BFB-di and trimer BFB-tri in three-dimensional space. As shown in the front and side views, the BODIPY core and meso-trimethylbenzene groups of both compounds exhibit a nearly orthogonal orientation, with dihedral angles ranging from 81.36° to 88.44°. Figure 1 a, 1c). The larger orthorhombic trimethylbenzene substituents are also the reason why the trimer has higher solubility than the dimer. Side view of BFB-di ( Figure 1 b) reveals the expected planar π-conjugated framework. The single-crystal structure confirms that BFB-di possesses C2 symmetry, with its symmetry axis passing through the central fused benzene ring, and the symmetry units being meta-trimethylyl, BODIPY, and furan rings. In contrast, the trimer BFB-tri ( Figure 1 d) Exhibits a slight bend, with the terminal BODIPY unit bending in the opposite direction. This distortion originates from the stress exerted by the central BODIPY unit, which connects the two terminal subunits, leading to molecular asymmetry. The C–C bonds connecting the BODIPY ring and the benzene ring reveal the conjugated nature of the fused structure. Under C2 symmetry, the C–C bond length in BFB-di is uniform at 1.443 Å. However, in BFB-tri, these bond lengths vary significantly: bonds closer to the central BODIPY are shorter (1.419–1.431 Å), while bonds further away are longer (1.433–1.489 Å), resulting in structural distortion that reflects steric hindrance and electronic delocalization. Overall, the C–C bond length ranges from 1.42 to 1.49 Å, while the C–O bond length in the furan ring ranges from 1.32 to 1.49 Å. Figure 1a, 1c), consistent with typical furan ring structures. The extension of the π-conjugated system also modulates the intermolecular packing. In the BFB-di crystal structure, a short π–π packing distance of 3.54 Å was observed ( Figure 1 (b) This distance is within the expected range for aromatic stacking interactions. For BFB-tri, the π-π distance increases by 0.43 Å ( Figure 1 d) This is primarily attributed to the steric hindrance of the central mesitylene substituent, which weakens the π-π interactions. These interactions promote highly oriented stacking paths, resulting in the parallel alignment of dimers and trimers in the crystalline state.

[0043] 2. NICS(0) value, ACID spectrum and ESP analysis To reveal the aromaticity patterns of these oligomeric BODIPYs, we first calculated the core-independent chemical shifts (NICS(0)) of the benzofuran-fused BODIPYs, as shown in the figure. Figure 2 As shown. Furthermore, the interaction of aromaticity among multiple rings and the changes in the current loop were further investigated using the induced current density anisotropy (ACID) plots of BFB-di and BFB-tri. Figure 2 (b) In BFB-di and BFB-tri, the furan ring exhibits typical aromaticity, with NICS(0) values ​​ranging from -4.11 to -4.33 ppm, while the ACID plots show a clockwise current loop, further confirming the aromaticity of these rings. Notably, there is a significant difference in aromaticity between the pyrrole rings near the furan ring and the outer pyrrole rings. The NICS(0) values ​​of the pyrrole rings near the furan ring range from -6.27 to -6.52 ppm, while those of the outer pyrrole rings range from -5.99 to -6.02 ppm, and both ACID plots show a clockwise current loop, indicating that the introduction of the furan ring significantly affects the aromaticity of the pyrrole ring. Furthermore, the central boron-nitrogen six-membered heterocycle in BFB-tri exhibits non-aromaticity, and its non-aromaticity characteristics show a trend of being weak in the middle and strong at both ends. The NICS(0) value decreased from 2.85 ppm to 2.15 ppm, and the ACID diagram showed a counterclockwise current loop, revealing that the introduction of heteroatoms produced electronic effects in the local region and revealed the change in electron density during the π delocalization process.

[0044] To further investigate the effect of oxygen atom fusion on the potential distribution, we calculated the electrostatic potential (ESP) spectrum of the dye at the TPSSh / 6-31+G* level. Figure 2c). The results show that fluorine atoms are located in the oxygen atom-fused region and the center of the BODIPY framework, and the introduction of oxygen atoms significantly changes the potential distribution around the F atoms. With the gradual increase in the benzofuran fusion degree (from BOP → BFB-mono → bis-BFB), the strong electronegativity of oxygen atoms gradually enhances the negative potential around the F atoms, leading to sequential changes in the potential of the central region of the BF2 group: bis-BFB (-54.72 kcal / mol) < BFB-mono (-50.62 kcal / mol) < BOP (-45.22 kcal / mol). However, with the further increase in the polymer scale, the potential values of the dimer BFB-di and trimer BFB-tri tend to be consistent. Compared with BFB-mono and bis-BFB, the electronegativity of the central region of the BF2 group weakens, the potential of the BF2 group increases to -47.43 to -47.89 kcal / mol, and the potential of the oxygen atom increases to -33.78 to -34.32 kcal / mol. This phenomenon can be attributed to the intermolecular π-electron delocalization effect, which is consistent with the results of the ACID diagram and NICS(0) values. With the increase in the number of polymers, the intermolecular π-π interaction becomes more significant, and the delocalization process of electron density in the polymer structure is more extensive, resulting in a uniform distribution of electron density, thus weakening the concentration effect of electron density around the BF2 group and oxygen atoms, and then leading to an increase in potential.

[0045] 3. Study on Photophysical Properties We characterized the photophysical properties of the monomer BOP (meso-trimethylphenyl-BODIPY, synthesized according to the methods described in Prior Art 1 or Prior Art 2), mono-fused (BFB-mono), bis-fused (bis-BFB), and the benzofuran-fused BODIPY dimer BFB-di and trimer BFB-tri with a large π-conjugated system by ultraviolet / visible absorption spectroscopy and fluorescence spectroscopy ( Figure 3 a). Compared with the monomer BOP (meso-trimethylphenyl-BODIPY), with the increase in the number of benzofuran fusion units and the number of BODIPY monomers, the absorption peaks of benzofused BODIPYs show a monotonic red shift, and their macroscopic colors gradually change from orange-yellow to dark green. With the red shift of the absorption peak, the molar extinction coefficient ε increases synchronously. Starting from the dimer BFB-di, ε increases in multiples. For example, the ε of the trimer BFB-tri at 706 nm in dichloromethane is as high as 400000 M - ¹ cm -The significant value of ¹ indicates its potential as a near-infrared strong absorbing dye. The absorption sidebands of oligomers BFB-di and BFB-tri are further extended into the near-infrared region, and multiple vibrationally resolved redshift absorption bands appear. In toluene solution, the maximum π-conjugated skeleton of BFB-tri causes the absorption and emission peaks to be redshifted by 213 nm (λmax=716 nm) and 219 nm (λem=733 nm) compared to BOP, respectively, with the maximum emission peak reaching as high as 808 nm. Such a large redshift and enhanced ε jointly confirm that the increasing BODIPY and benzofuran units do not destroy the conjugation continuity, but rather extend the effective conjugation length along the entire skeleton through π-orbital overlap; this conclusion is consistent with the ACID plot ( Figure 2 The global paramagnetic ring current spanning all fused rings in b) and the increasing negative value of NICS(1)zz corroborate each other, fully demonstrating that electronic delocalization maintains high coherence throughout the entire π-framework. According to frontier molecular orbital calculations, the S1 state of the monofused (BFB-mono), bifused (bis-BFB), and large π-conjugated benzofuran-fused BODIPY dimer BFB-di and trimer BFB-tri is mainly contributed by the HOMO→LUMO transition. In addition, with the increase of conjugated structure, the dimer BFB-di and trimer BFB-tri show new absorption peaks at 583 nm and 641 nm, respectively. Figure 3 a) These absorption peaks are mainly generated by intramolecular local charge transfer, corresponding to the HOMO-1→LUMO and HOMO→LUMO+1 transition processes. Figure 3 d). Notably, during the progression of benzofuran fusion from BOP to BFB-mono to bis-BFB, the system maintained an ultra-high fluorescence quantum yield (ΦF) of 91.1–97.9%, indicating that single-sided or double-sided fusion only slightly perturbs the radiation channel of the S1 state; however, starting from the dimer, ΦF drops sharply to 61.1–69.8%, and the trimer BFB-tri further slips to 55.4–65.4%. This decreasing trend is synchronized with the contraction of the HOMO–LUMO bandgap (ΔEBFB-di=2.06eV, ΔEBFB-tri=1.82eV), revealing the enhanced S1→S0 internal conversion dominated by the bandgap law. Figure 3c). Nevertheless, the ΦF of BFB-tri is still significantly higher than that of the anthraco-fused trimer BODIPY (13-26%) and benzo-fused trimer BODIPY (7-13%) reported in the literature, confirming that the introduction of oxygen atoms can moderately break the rigid planarity of the π-backbone and suppress nonradiative transitions, thereby achieving optimal luminescence efficiency in the fully fused oligomeric system. The strong luminescence properties and high molar absorptivity of dimer BFB-di and trimer BFB-tri make them the brightest fluorophores, especially trimer BFB-tri, which has an absorption wavelength exceeding 716 nm and an emission wavelength exceeding 728 nm, showing broader application prospects, including in the field of fluorescence bioimaging.

[0046] 4. Theoretical Calculation DFT calculations further revealed the optical properties and electronic structure of the monofused (BFB-mono), bisfused (bis-BFB), and large π-conjugated benzofuran-fused BODIPY dimer BFB-di and trimer BFB-tri systems. Figure 3c). Analysis of the HOMO-LUMO electron density distribution shows that for BOP, BFB-mono, and bis-BFB, the LUMO is mainly located on the indenoid framework, while the HOMO runs through the entire fused ring system. Furthermore, as the benzofuran fusion degree progresses from BOP to BFB-mono to bis-BFB, the LUMO energy level fluctuates within a narrow range, approximately 0.04-0.06 eV, while the HOMO energy level continuously increases from -5.95 eV for BOP to -5.68 eV for BFB-mono and then to -5.48 eV for bis-BFB. This indicates that benzofuran fusion based on a single BODIPY narrows the HOMO-LUMO band gap by affecting the HOMO energy level, resulting in a redshift in the absorption / fluorescence spectrum. However, starting from the dimer, the variation pattern of the HOMO and LUMO energy levels changes significantly. Specifically, the HOMO energy levels of the dimer BFB-di and bis-BFB remained almost identical, while the LUMO energy level decreased significantly, from -3.28 eV for bis-BFB to -3.48 eV for BFB-di. The similarity between BFB-di and bis-BFB lies in the fact that they both contain the same number of furan rings; the difference is that BFB-di has an additional BODIPY subunit. Therefore, starting from the dimer stage, the change in the HOMO energy level is mainly determined by the number of furan rings; as the number of furan rings increases, the HOMO energy level tends to increase. The change in the LUMO energy level, however, is related to the number of BODIPY subunits; as the number of BODIPY subunits increases, the LUMO energy level continuously decreases. As expected, the HOMO and LUMO energy level changes of the trimer increased from -5.51 eV in the dimer BFB-di to -5.36 eV, while the LUMO energy level decreased from -3.48 eV to -3.54 eV, resulting in a narrowing of the HOMO-LUMO band gap. TD-DFT calculations, based on the analysis of vertical transition energy, oscillator strength (f), and energy level orbital contributions, confirm that the S0→S1 transition contribution of all benzofuran-fused BODIPY oligomers mainly originates from the HOMO→LUMO transition. This conclusion is consistent with the observations of the highest UV absorption peaks of all benzofuran-fused oligomers presented in this paper.

[0047] 5. Electrochemical Research We investigated the electrochemical properties of monomeric BOP, monofused BFB-mono, difused bis-BFB, and benzofuran-fused BODIPY dimers BFB-di and BFB-tr with large π-conjugated systems using cyclic voltammetry. The experimental results are consistent with theoretical calculations. Figure 4As shown. The study found that the formation of free radical anions within the BODIPY core is closely related to the reduction potential. With the increase in the number of BODIPY subunits, the number of reversible reduction potentials gradually increases, and the amplitude of these potentials also gradually rises. This change causes the LUMO energy level to gradually decrease, from -3.52 eV for monomeric BOP to -3.59 eV for BFB-di, and then to -3.68 eV for BFB-tri. This phenomenon is highly consistent with theoretically calculated LUMO results. This trend indicates that the longer the conjugation length of the benzofuran-fused BODIPY system, the stronger its reducing power, thereby enhancing the material's electron-accepting ability. The oxidation behavior of monofused BFB-mono is similar to that of monomeric BOP, forming an irreversible oxidation potential, but the oxidation potential shifts significantly to the left. In contrast, the double-fused bis-BFB stabilized the cationic radicals, leading to a reversible oxidation potential, which shifted 0.24 V to the left compared to the single-fused BFB-mono. The oxidation behaviors of the dimer BFB-di and trimer BFB-tri were more similar, with initial oxidation occurring at 0.71 V and 0.58 V respectively, forming a set of reversible oxidation peaks. The second oxidation peak was formed by the overlap of cationic radicals from different benzofuran rings. Compared to BOP, BFB-tri, as a large π-conjugated system, underwent significant changes in both its LUMO and HOMO energy levels. The LUMO level decreased from -3.52 eV in BOP to -3.68 eV in BFB-tri, a decrease of 0.16 eV, while the HOMO level increased from -5.86 eV in BOP to -5.38 eV in BFB-tri, an increase of 0.48 eV. Figure 4 The narrowing of the band gap further demonstrates the effective π-conjugation in BFB-tri, highlighting the profound influence of the large π-conjugated system on the electronic properties of the BODIPY framework.

[0048] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions or improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A BODIPY-based luminescent material, characterized in that, Including any one of Equations I-4: , , or Formula I; Formula II; Formula III Formula IV.

2. The method for preparing the BODIPY-based luminescent material according to claim 1, characterized in that, If the BODIPY-based luminescent material is a compound represented by Formula I, Formula II, or Formula III, the following steps are included: Step 1: Under an inert atmosphere, the first compound and the second compound are mixed evenly and dissolved in a low-boiling-point organic solvent. A basic catalyst is added, and a substitution reaction is carried out at 75-85℃ to obtain the third compound. Step 2: Under an inert atmosphere, the third compound is dissolved in an organic solvent, and an organic palladium catalyst, 1,1'-binaphthyl-2,2'-bis(diphenylphosphine) and cesium carbonate are added and mixed evenly. A cyclization reaction is carried out at 110-120°C to obtain a luminescent material based on BODIPY. The first compound is or Any one of them; The second compound is or Any one of them; The third compound is , or Any one of them.

3. The method for preparing the BODIPY-based luminescent material as described in claim 2, characterized in that, In step one, the molar ratio of the first compound to the second compound is 1:1 to 1:

2.

4. The method for preparing the BODIPY-based luminescent material as described in claim 2, characterized in that, In step one, the low-boiling-point organic solvent is acetonitrile; In step one, the basic catalyst is potassium carbonate; In step one, the mass-to-volume ratio of the first compound to the low-boiling-point organic solvent is 0.005 g: 1 mL to 0.02 g: 1 mL; In step one, the molar ratio of the first compound to the basic catalyst is 1:2 to 1:2.2; In step one, the substitution reaction takes 30-50 minutes.

5. The method for preparing the BODIPY-based luminescent material as described in claim 2, characterized in that, In step two, the organic solvent is anhydrous toluene; In step two, the mass-to-volume ratio of the third compound to the organic solvent is 0.005 g: 1 mL to 0.02 g: 1 mL; In step two, the molar ratio of the third compound to the organopalladium catalyst, 1,1'-binaphthyl-2,2'-bis(diphenylphosphine) and cesium carbonate is 1:0.1-0.12:0.2:2; In step two, the cyclization reaction takes 12-14 hours.

6. A method for preparing a BODIPY-based luminescent material, characterized in that, If the BODIPY-based luminescent material is a compound represented by Formula IV, the following steps are included: S1. In an inert atmosphere, and After being mixed evenly, the mixture was dissolved in acetonitrile, potassium carbonate was added, and a substitution reaction was carried out at 75-85℃ to obtain the fourth compound. S2. Under an inert atmosphere, the fourth compound and Dissolved in acetonitrile, potassium carbonate was added, and a substitution reaction was carried out at 75-85℃ to give the fifth compound; S3. Dissolve the fifth compound in an organic solvent, add an organopalladium catalyst, 1,1'-binaphthyl-2,2'-bis(diphenylphosphine) and cesium carbonate, mix thoroughly, and carry out a cyclization reaction at 110-120°C to obtain the BODIPY-based luminescent material; wherein, in S1, the structure of the fourth compound is as follows: ; In S2, the structure of the fifth compound is as follows: .

7. The method for preparing the BODIPY-based luminescent material as described in claim 6, characterized in that, In either S1 or S2, the substitution reaction takes 30-50 minutes. In S1, the The mass-to-volume ratio of the acetonitrile to the acetonitrile is 0.005 g: 1 mL to 0.02 g: 1 mL; In S2, the mass-to-volume ratio of the fourth compound to the acetonitrile is 0.005 g: 1 mL to 0.01 g: 1 mL.

8. The method for preparing the BODIPY-based luminescent material as described in claim 6, characterized in that, In S3, the mass-to-volume ratio of the fifth compound to the organic solvent is 0.005 g: 1 mL to 0.01 g: 1 mL; In S3, the molar ratio of the fifth compound, the organopalladium catalyst, 1,1'-binaphthyl-2,2'-bis(diphenylphosphine) and cesium carbonate is 1:0.1-0.12:0.2:2; In S3, the cyclization reaction takes 12-14 hours.

9. The application of the BODIPY-based luminescent material as described in claim 1 in the preparation of near-infrared fluorescent dyes.

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