D-pi-A type triarylboronaphthalene derivative with double-state emission characteristic as well as preparation method and application of D-pi-A type triarylboronaphthalene derivative

Abstract

The invention provides a D-pi-A type triarylboronaphthalene derivative with a double-state emission characteristic as well as a preparation method and application thereof, and belongs to the technical field of carbocyclic compounds. The structural general formula of the naphthalene derivative is as shown in formula I, and Ar is phenyl or p-methoxyphenyl. The preparation method of the naphthalene derivative comprises the following steps: performing lithiation treatment on a brominated arylamine precursor with n-butyllithium in an inert atmosphere, and then adding dimetyl boron fluoride for quenching to obtain the corresponding naphthalene derivative, and the brominated arylamine precursor is 2-bromine-6-(N, N '-diphenylamino) naphthalene or 2-bromine-6-[N, N'-bis (4-methoxyphenyl) amino] naphthalene. The compound provided by the invention keeps higher fluorescence quantum yield in various solvents, still has strong luminescence in solid states (powder and films), and belongs to a DSE material with excellent performance.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of carbocyclic compounds, and particularly relates to a D-π-A type triarylboron naphthalene derivative with dual-state emission characteristics, a preparation method of the compound, and application of the compound in organic light-emitting devices, fluorescence sensing, fluorescence imaging and the like. BACKGROUND

[0002] As an important class of functional materials, organic fluorescent materials have been widely used in biological imaging, information storage, photothermal diagnosis and treatment, biological sensing, and organic light-emitting diodes (OLEDs). Traditional organic fluorescent molecules usually have a rigid planar π-conjugated skeleton, which is conducive to improving the radiation transition probability between the ground state (S0) and the first excited state (S1), thereby obtaining a high fluorescence quantum efficiency in dilute solution. However, such planar molecules often exhibit serious intermolecular π-π stacking in aggregation or solid state, resulting in significant fluorescence quenching, i.e., the so-called aggregation-induced quenching (ACQ) effect, which severely limits the application of organic fluorescent materials in solid-state devices. To overcome the ACQ problem, researchers have proposed the concept of aggregation-induced emission (AIE), which involves introducing multiple non-coplanar rotatable π-structure units into the molecule to suppress π-π stacking in the solid state, thereby obtaining strong fluorescence in aggregation or solid state. However, due to the free rotation and vibration of multiple rotatable π-structure units in dilute solution, non-radiative transitions are significantly enhanced, and AIE molecules usually emit strongly only in the solid state, with weak or almost no emission in solution. Therefore, whether ACQ-type or AIE-type molecules, most of them can only exhibit high-efficiency fluorescence in one of the two states, i.e., dilute solution or solid state, which significantly limits their application scenarios. In recent years, dual-state emission (DSE) fluorescent molecules that exhibit high luminescent efficiency in both solution and solid state have attracted widespread attention. DSE molecules are expected to bridge ACQ-type and AIE-type fluorescent molecules, enabling compatible applications in both dispersed and aggregated states. Existing strategies for achieving DSE characteristics mainly rely on constructing twisted configurations and improving molecular rigidity, such as introducing bulky substituents or constructing complex multi-aromatic ring twisted structures. Such designs often involve complicated synthesis steps and complex molecular structures, which are not conducive to large-scale preparation and further development of structural systems.

[0003] Triarylboron systems containing bismesitylboron (BMes2) are often used to construct luminescent molecules with intramolecular charge transfer (ICT) characteristics and large Stokes shift due to their strong electron acceptor properties and large steric hindrance.

[0004] There are various D-π-A type triarylboron compounds based on BMes2 disclosed in the prior art, four typical structures of which are as follows: ; It can be seen that the above-mentioned D-π-A structure luminophore based on BMes2 has low fluorescence quantum yield, regardless of simple skeleton or complex twisted skeleton. SUMMARY

[0005] In view of the deficiencies in the prior art, the present application provides a D-π-A type triarylboron naphthalene derivative with dual-state emission characteristics, a preparation method and application thereof, by introducing an electron acceptor dimethylboron (BMes2) group and an electron donor diarylamine (NAr2) group at the 2,6 positions of the rigid naphthalene ring, the obtained molecule has excellent fluorescence quantum efficiency in dilute solution and solid state (including powder and thin film), thereby realizing high-efficiency dual-state emission characteristics.

[0006] In order to achieve the above-mentioned purpose, the present application adopts the following technical solutions: A D-π-A type triarylboron naphthalene derivative with dual-state emission characteristics, the structure general formula of the derivative is: ; The Ar is a phenyl group or a p-methoxyphenyl group.

[0007] In the general formula structure: The naphthalene ring is a central π bridge linking unit; The 2-position of the naphthalene ring is connected with a dimethylboron (BMes2) acceptor group; The 6-position of the naphthalene ring is connected with a diarylamine (NAr2) donor group, specifically a diphenylamine (NPh2) group or N N a p-methoxyphenylamine (N OMe Ph2) group.

[0008] The preparation method of the naphthalene derivative is to perform lithiation treatment on a bromoarylamine precursor under an inert atmosphere by using n-butyl lithium, and then to add dimethylboron fluoride to quench, so as to obtain the corresponding naphthalene derivative, the bromoarylamine precursor is 2-bromo-6-( N N ’-diphenylamino)naphthalene or 2-bromo-6-[ N N ’-di(4-methoxyphenyl)amino)naphthalene.

[0009] The preparation method of the naphthalene derivative is to reduce the temperature of a tetrahydrofuran solution of the bromoarylamine precursor to-77 to-79℃, slowly drop n-butyl lithium under nitrogen protection, continue to react at-77 to-79℃ for 1.8 to 2.2 hours after the drop is completed, slowly inject a tetrahydrofuran solution of dimethylboron fluoride into the reaction system under a nitrogen atmosphere, and then slowly warm to room temperature, react at room temperature for 11 to 13 hours, after the reaction is completed, the target product is obtained through extraction, drying, filtration, concentration and purification. ​​​

[0010] The molar ratio of the bromoaniline precursor, n-butyllithium, and dimethylboron fluoride is (0.9-1.1):(0.9-1.1):(1.4-1.6).

[0011] The molar concentration of the tetrahydrofuran solution of the bromoaniline precursor is 0.09-0.11 mol / L; and the molar concentration of the tetrahydrofuran solution of the dimethylboron fluoride is 0.14-0.16 mol / L.

[0012] The preparation method of the bromoaniline precursor is as follows: taking 2-bromo-6-naphthylamine as a starting material, reacting with iodobenzene or 4-methoxyiodobenzene through Ullmann coupling reaction in the presence of a copper catalyst under alkaline conditions and in an inert atmosphere to obtain the bromoaniline precursor.

[0013] The preparation method of the bromoaniline precursor is as follows: taking 2-bromo-6-naphthylamine, cuprous iodide, 1,10-phenanthroline, and potassium hydroxide, replacing nitrogen, adding iodobenzene or 4-methoxyiodobenzene, adding anhydrous toluene, heating the reaction system to 128-132 DEG C for 11.5-12.5 h, cooling the reaction system to room temperature after the reaction is completed, and then extracting, drying, filtering, concentrating, and separating and purifying to obtain the bromoaniline precursor.

[0014] The molar ratio of the 2-bromo-6-naphthylamine, cuprous iodide, 1,10-phenanthroline, and potassium hydroxide is (0.9-1.1):(0.9-1.1):(0.9-1.1):(19-21). The molar ratio of the 2-bromo-6-naphthylamine and iodobenzene or 4-methoxyiodobenzene is (0.9-1.1):(9-11). The mass-volume ratio of the 2-bromo-6-naphthylamine and anhydrous toluene is 1g:50-55mL.

[0015] The naphthalene derivative is applied in organic light-emitting devices, fluorescent sensing, and fluorescent imaging.

[0016] The present application effectively inhibits intermolecular π-π stacking in a solid state and realizes efficient dual-state emission in a solution state and a solid state by introducing bulky BMes2 and NAr2 groups at 2,6 positions under the premise of maintaining a rigid planar structure of a naphthalene ring.

[0017] Compared with the prior art, the present application has the following beneficial effects: (1) Simple structure and short synthesis route: D-π-A type triarylboron naphthalene derivatives can be obtained by only relying on Ullmann coupling and simple boronization steps, avoiding complex twisted skeleton construction, and being suitable for scale-up preparation and structure expansion.

[0018] (2) Excellent dual-state emission performance: the compounds of the present application maintain high fluorescence quantum yield in various solvents, and still have strong luminescence in solid state (powder and thin film), which belong to excellent DSE materials. The fluorescence quantum efficiency of BNPh-Nap in cyclohexane is 0.97, the fluorescence quantum efficiency of BNOPh-Nap in cyclohexane is 0.71, the fluorescence quantum efficiency of BNPh-Nap in powder is 0.67, the fluorescence quantum efficiency of BNOPh-Nap in powder is 0.91, the fluorescence quantum efficiency of BNPh-Nap in thin film is 0.51, and the fluorescence quantum efficiency of BNOPh-Nap in thin film is 0.99.

[0019] (3) Wide application scenarios: due to the high efficiency of solution and solid state luminescence, the compounds of the present application are suitable for various scenarios requiring cross-phase state use such as organic light-emitting diodes, sensing, anti-counterfeiting and biological imaging, and have good application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0020] The drawings accompanying the specification of the present application serve to provide further understanding of the present application, and the exemplary embodiments of the present application and the description thereof serve to explain the present application, and do not constitute an improper limitation on the present application.

[0021] Figure 1 (a) is the molecular structure schematic diagram of BNPh-Nap, and (b) is the molecular structure schematic diagram of BNOPh-Nap; (a) is the molecular structure schematic diagram of BNPh-Nap, and (b) is the molecular structure schematic diagram of BNOPh-Nap; Figure 2 (a) is the molecular structure schematic diagram of BNPh-Nap, and (b) is the molecular structure schematic diagram of BNOPh-Nap; (a) is the molecular structure schematic diagram of BNPh-Nap, and (b) is the molecular structure schematic diagram of BNOPh-Nap; Figure 3 (a) is the molecular structure schematic diagram of BNPh-Nap, and (b) is the molecular structure schematic diagram of BNOPh-Nap; (a) is the molecular structure schematic diagram of BNPh-Nap, and (b) is the molecular structure schematic diagram of BNOPh-Nap; Figure 4 (a) is the molecular structure schematic diagram of BNPh-Nap, and (b) is the molecular structure schematic diagram of BNOPh-Nap; Wherein (a) is the fluorescence spectrum of BNPh-Nap in different solvents, (b) is the fluorescence spectrum of BNOPh-Nap in different solvents; Figure 5 UV-Vis absorption spectrum and fluorescence spectrum of the compound BNPh-Nap and BNOPh-Nap in solid state of the present application; Figure 6 Test spectrum of the absolute quantum efficiency of the compound BNPh-Nap in powder of the present application; Figure 7 Test spectrum of the absolute quantum efficiency of the compound BNPh-Nap in thin film of the present application; Figure 8 Test spectrum of the absolute quantum efficiency of the compound BNOPh-Nap in powder of the present application; Figure 9 Test spectrum of the absolute quantum efficiency of the compound BNOPh-Nap in thin film of the present application; Figure 10 NMR hydrogen spectrum of the compound BrNOPh-Nap of the present application; Figure 11 NMR hydrogen spectrum of the compound BNPh-Nap of the present application; Figure 12 NMR carbon spectrum of the compound BNPh-Nap of the present application; Figure 13 NMR hydrogen spectrum of the compound BNOPh-Nap of the present application; Figure 14 NMR carbon spectrum of the compound BNOPh-Nap of the present application; Figure 15 Synthetic route of the naphthalene derivative of the present application. DETAILED DESCRIPTION

[0022] It should be noted that the following detailed description is exemplary in nature and is intended to provide further description of the present application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0023] Example 1: Preparation of BrNPh-Nap Into a dry 250 mL Schlenk tube was added a magnetic stir bar, 2-bromo-6-naphthylamine (1.0 g, 4.4 mmol), cuprous iodide (960 mg, 4.4 mmol), 1,10-phenanthroline (793 mg, 4.4 mmol) and potassium hydroxide (4.9 g, 88 mmol), after purging with nitrogen, iodobenzene (5.16 mL, 44 mmol) and anhydrous toluene (50 mL) were added and the reaction mixture was heated to 130 °C for 12 h. After the reaction was completed, the reaction mixture was cooled to room temperature, then extracted with ethyl acetate, the organic phases were combined and dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by column chromatography on silica gel (petroleum ether: dichloromethane = 5:1, v / v) to give the product BrNPh-Nap (1.28 g, 3.43 mmol) as a white solid in 78% yield. R f = 0.30) and 7.53 (d, J = 9.0 Hz, 1H), 7.44–7.33 (m, 2H), 7.20 (dd, J = 9.0, 2.3 Hz, 1H), 7.13 (d, J = 8.9 Hz, 4H), 6.85 (d, J = 9.0 Hz, 4H), 3.81 (s, 6H).

[0024] Example 2: Preparation of BrNOPh-Nap The preparation method of BrNOPh-Nap is similar to that of BrNPh-Nap, except that 4-methoxyiodobenzene is used instead of iodobenzene and the amounts of raw materials are adjusted. The raw materials and their amounts are as follows: 2-bromo-6-naphthylamine (1.1 g, 5.0 mmol), 4-methoxyiodobenzene (11 g, 50 mmol), cuprous iodide (950 mg, 5.0 mmol), 1,10-phenanthroline (901 mg, 5.0 mmol), potassium hydroxide (5.6 g, 100 mmol) and anhydrous toluene (60 mL). Purification by column chromatography on silica gel (petroleum ether: dichloromethane = 2:1, v / v) to give the product BrNOPh-Nap (1.26 g, 2.9 mmol) as a white solid in 58% yield. R f = 0.20) and 7.53 (d, J = 9.0 Hz, 1H), 7.44–7.33 (m, 2H), 7.20 (dd, 1 H NMR (400 MHz, CDCl3) δ 7.83 (s, 1H),7.53 (d, J = 9.0 Hz, 1H), 7.44–7.33 (m, 2H), 7.20 (dd, J = 9.0, 2.3 Hz, 1H), 7.13(d, J = 1.8 Hz, 1H), 7.08 (d, J = 8.9 Hz, 4H), 6.85 (d, J = 9.0 Hz, 4H), 3.81 (s,6H).

[0025] Example 3: Preparation of BNPh-Nap Add a magnetic flask and 2-bromo-6-( N , N '-Diphenylamino'-naphthalene BrNPh-Nap (374 mg, 1.0 mmol) was purged with nitrogen and then anhydrous tetrahydrofuran (10 mL) was added. The system temperature was lowered to -78 °C, and n-butyllithium (0.4 mL, 2.5 M, 1.0 mmol) was slowly added dropwise under nitrogen protection. After the addition was complete, the reaction was continued at -78 °C for 2 h. Dimethylboron fluoride (400 mg, 1.5 mmol) was dissolved in anhydrous tetrahydrofuran (10 mL) under a nitrogen atmosphere. After complete dissolution, it was slowly injected into the reaction flask using a syringe. The temperature was then slowly raised to room temperature, and the reaction was carried out overnight (12 h) at room temperature. After the reaction was completed, water was added to the reaction system to quench the reaction. The system was then extracted with ethyl acetate, the organic phases were combined, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The resulting residue was purified by silica gel column chromatography (petroleum ether: dichloromethane = 5:1). R f =0.50), yielding a blue solid product BNPh-Nap (400 mg, 0.73 mmol), in 73% yield. Mp 256.1–256.9 °C; 1 H NMR (400MHz, CDCl3) δ 7.96 (s, 1H), 7.67 (d, J = 9.2 Hz, 1H), 7.48 (s, 2H), 7.36–7.27(m, 5H), 7.23 (dd, J = 8.8, 2.4 Hz, 1H), 7.20–7.14 (m, 4H), 7.08 (t, J = 7.2 Hz,2H), 6.84 (s, 4H), 2.33 (s, 6H), 2.04 (s, 12H); 13 C NMR (101 MHz, CDCl3) δ146.40, 146.33, 139.83, 137.40, 137.29, 135.64, 131.96, 129.57, 128.36,128.20, 127.11, 124.93, 124.04, 122.52, 122.18, 117.07,76.30, 75.98, 75.67,22.49, 20.21; HRMS (ESI) m / z: [M+H] + Calcd for C 40 H 38BN: 544.3170; Found544.3163.

[0026] Example 4: Preparation of BNOPh-Nap The preparation method of BNOPh-Nap is similar to that of BNPh-Nap. Using 2-bromo-6-[ N , N '-Di(4-methoxyphenyl)amino]naphthalene BrNOPh-Nap (433 mg, 1.0 mmol) was used instead of BrNPh-Nap, and the other preparation methods were the same as in Example 3. It was separated and purified by silica gel column chromatography (petroleum ether: dichloromethane = 2:1). R f = 0.40), yielding the green solid product BNOPh-Nap (400 mg, 0.66 mmol), in 66% yield. Mp 265.3–266.0 °C; 1 H NMR (400 MHz, CDCl3) δ 7.92 (s, 1H), 7.61 (d, J = 8.8 Hz, 1H), 7.47–7.40 (m, 2H), 7.17–7.07(m, 6H), 6.88–6.81 (m, 8H), 3.81 (s, 6H), 2.32 (s, 6H), 2.03 (s, 12H); 13 C NMR(101 MHz, CDCl3) δ 155.28, 147.31, 140.93, 139.83, 139.44, 137.51, 137.26,135.86, 132.08, 129.42, 127.21, 127.07, 126.09, 124.58, 120.21,113.76,113.16, 76.30, 75.99, 75.67, 54.45, 22.47, 20.20; HRMS (ESI) m / z: [M+H] + Calcdfor C 42 H 42 BNO2: 604.3381; Found 604.3373.

[0027] Example 5: Structural Features To reveal the stereostructural features of these compounds, their ground-state geometry was optimized using the PBE0 / 6-31G(d) theoretical calculation method (see...). Figure 2(Table 1). In the optimized ground-state geometry, both boron and nitrogen atom centers exhibit perfect planar structures, and the sum of the three sets of CBC or CNC bond angles reaches 360°, indicating a high degree of symmetry in its bond angle structure. Furthermore, another significant feature of the ground-state geometry is the helical arrangement of the three aryl substituents bonded to the boron or nitrogen atom. The twist angle between the benzene rings P1, P2, and the BC3 plane in BMes2 is 57.4°–60.0°, while in NPh2 and N… OMe The twist angles between the P3 and P4 planes of the benzene ring in Ph2 and the NC3 plane range from 41.3° to 46.6°. Notably, the BC3 and NC3 planes are highly coplanar with the naphthalene ring, with dihedral angles ranging from 18.2° to 19.3° and 30.1° to 35.5°, respectively. The helical arrangement of the NAr2 and BMes2 units is expected to effectively suppress intermolecular π-π interactions in the solid state, while the coplanarity of BC3 or NC3 with the naphthalene ring indicates a highly efficient conjugation effect throughout the molecule.

[0028] Table 1: Partial bond lengths (Å) and bond angles (Å) of the ground-state and excited-state geometries optimized by BNPh-Nap and BNOPh-Nap. o ) and dihedral ( o )data

[0029] Example 6: Optical Properties of Solutions In cyclohexane, the NPh2-substituted naphthalene derivative BNPh-Nap (concentration 2.0 × 10⁻⁶) -5 The longest wavelength absorption peak of (mol / L) is located at 399 nm, and the intensity is particularly high. ε =7.93×10 4 M -1 cm -1 (Table 2, Figure 3 ).

[0030] Furthermore, its fluorescence is also very significant, with a fluorescence quantum efficiency approaching 100%. Φ F =0.97). The fluorescence maximum is located at 428 nm, with a moderate Stokes shift (1.70 × 10⁻⁶). 3 cm -1 The high molar absorptivity of BNPh-Nap ( ε )and Φ F The moderate Stokes shift, likely attributed to the rigid planar structure of the naphthalene ring, facilitates the interconversion between the S0 and S1 states while suppressing significant structural relaxation in the S1 state. The radiative decay process of BNPh-Nap is very rapid, with a decay rate constant of 3.30 × 10⁻⁶.8 s -1 This further supports the high structural rigidity of the naphthalene ring. From BNPh-Nap to BNOPh-Nap, the amino group changes from NPh2 to N. OMe Ph2 leads to absorption (△) λ =11nm) and fluorescence (Δ) λ Both (e.g., 40 nm and 468 nm) exhibited a redshift. Therefore, the absorption and fluorescence maxima of BNOPh-Nap occurred at 410 nm and 468 nm, respectively. Compared to BNPh-Nap, BNOPh-Nap... ε and Φ F Slightly lower ( ε =6.22×10 4 M -1 cm -1 , Φ F =0.71), but the Stokes displacement increased (3.02×10). 3 cm -1 Meanwhile, radiative decay processes become slower, while non-radiative decay processes accelerate. The change in photophysical properties from BNPh-Nap to BNOPh-Nap may be attributed to N... OMe Ph2 has a stronger electron-donating ability than NPh2, which enhances charge separation in the S1 state and is accompanied by more structural relaxation.

[0031] To investigate the charge transfer properties of BNPh-Nap and BNOPh-Nap, the effect of solvent on absorption and fluorescence properties was examined (Table 2). Figure 4 The concentration of the above compound in the solvent is 2.0 × 10⁻⁶. -5 mol / L.

[0032] Although no significant solvation effect was observed in absorption, both compounds exhibited a clear solvation effect in fluorescence. With increasing solvent polarity, from cyclohexane to THF, the fluorescence of BNPh-Nap and BNOPh-Nap red-shifted by 52 nm and 68 nm, respectively. Notably, BNOPh-Nap exhibited blue fluorescence in cyclohexane, green in toluene, yellow-green in chloroform, and finally bright yellow in tetrahydrofuran; while BNPh-Nap remained consistently in the blue fluorescence region. Lippert-Mataga plots were used to compare the polarization of the two molecules in the excited state. The results showed that the Stokes shift (ΔΔ) v ) and solvent polarity parameter (Δ f There is a significant linear relationship between them. The slope of BNPh-Nap is 1.08 × 10⁻⁶. 4 Slightly smaller than BNOPh-Nap's 1.18 × 10⁻⁶.4 This indicates that BNOPh-Nap exhibits stronger charge transfer properties compared to BNPh-Nap, which may stem from the N... OMe Ph2 has a stronger electron-donating ability compared to NPh2. This is accompanied by a redshift in fluorescence. Φ F The fluorescence decreases with increasing solvent polarity, a phenomenon typical of excited-state charge transfer characteristics. Notably, both compounds maintain strong fluorescence in highly polar tetrahydrofuran, with BNPh-Nap exhibiting particularly strong fluorescence. Φ F The value is 0.67, for BNOPh-Nap Φ F The value is 0.20. The high concentrations of the two compounds in different solvents... Φ F The values ​​indicate that they exhibit excellent fluorescence properties in dilute solutions.

[0033] Example 7: Optical Properties of Solid State In addition to exhibiting bright fluorescence in solution, these two naphthalene derivatives also exhibit strong fluorescence in the solid state, whether in powder or film.

[0034] 1. Preparation of powder samples: Two naphthalene derivatives purified by column chromatography were dissolved separately in dichloromethane. The resulting solutions were added dropwise to a large amount of n-hexane under continuous vigorous stirring. During the addition, solid powder was observed to gradually precipitate. Subsequently, the solids were filtered using a sintered glass funnel and washed repeatedly with n-hexane to remove residual solvent. Finally, the washed solid powders were placed in a vacuum drying oven and dried at 40°C for 12 hours to constant weight, yielding dried blue and green powder samples.

[0035] 2. Preparation of thin film samples: The purified blue and green naphthalene derivative powders were dissolved separately in dichloromethane to prepare a solution with a concentration of 1.0 × 10⁻⁶. -3 A mol / L precursor solution was prepared and filtered through a filter membrane. A clean quartz substrate was fixed on a spin coater, and an appropriate amount of solution was dropped evenly onto the center of the substrate. The solution was spin-coated at 800 rpm for 10 seconds to spread, and then at 3000 rpm for 30 seconds to evaporate the solvent and form a film. Subsequently, the film was annealed on an 80℃ hot plate for 10 minutes to remove residual solvent and stabilize the film layer, finally obtaining a solid film sample with a smooth surface and uniform thickness.

[0036] The photophysical properties of the two naphthalene derivatives in solid state are shown in Table 2. Spectroscopically, the absorption spectra of the films were found to be similar to those in solution, with only a 6 nm (BNPh-Nap) and 5 nm (BNOPh-Nap) redshift compared to their spectra in cyclohexane, respectively. This slight redshift from solution to film indicates the absence of strong intermolecular π-π interactions in the S0 state, likely due to the significant steric hindrance of BMes2 and NAr2. Regarding emission, the fluorescence spectra of the films were very similar to those of the corresponding powders. Although the solid-state fluorescence showed a redshift compared to the fluorescence in cyclohexane, the emission maximum was between that in toluene and chloroform, further supporting the conclusion that strong intermolecular π-π interactions were lacking in the S1 state. Furthermore, both compounds exhibited high [missing information - likely related to high efficiency or high performance] in the solid state. Φ F Values ​​of BNPh-Nap powders and films Φ F The values ​​are 0.67 and 0.51 respectively, while BNOPh-Nap's are 0.91 and 0.99. It's worth noting that BNOPh-Nap in solid-state... Φ F The value is close to 100%. Fluorescence kinetic studies indicate that the improved emission efficiency of BNOPh-Nap in the solid state stems from the suppression of non-radiative decay processes. Given N... OMe Ph2 and NPh2 exhibit similar spatial effects, and the suppression of nonradiative decay processes in BNOPh-Nap likely originates from N. OMe Ph2 has a stronger electron-donating ability than NPh2, which may enhance charge transfer, resulting in a larger Stokes shift and reduced nonradiative decay via self-absorption. This hypothesis is supported by experimental results, which show that the Stokes shift of BNOPh-Nap in the thin film state is greater than that of BNPh-Nap. Considering the high electron-donating capacity of BNOPh-Nap and BNPh-Nap in solution and solid states... Φ F These values ​​suggest that they could serve as promising fluorescent emitting materials with excellent DSE properties.

[0037] Table 2: Photophysical properties of BNPh-Nap and BNOPh-Nap in different solutions and solids

[0038] a Only the absorption peak at the longest wavelength is given; b Relative quantum efficiency measured using reference coumarin 307; c Absolute quantum efficiency measured using an integrating sphere.

Claims

1. A D-π-A type triarylbornaphthalene derivative with dual-state emission characteristics, characterized in that: The general structural formula of the naphthalene derivative is: ； The Ar is phenyl or p-methoxyphenyl.

2. The method for preparing the naphthalene derivative according to claim 1, characterized in that: The bromoaryl amine precursor was lithiated with n-butyllithium under an inert atmosphere, followed by quenching with dimethylboron fluorine to obtain the corresponding naphthalene derivative. The bromoaryl amine precursor was 2-bromo-6-( N , N '-Diphenylamino)naphthalene or 2-bromo-6-[ N , N '-Di(4-methoxyphenyl)amino]naphthalene.

3. The preparation method according to claim 2, characterized in that: The temperature of the tetrahydrofuran solution of the bromoarylamine precursor was lowered to -77 to -79 °C, and n-butyllithium was slowly added dropwise under nitrogen protection. After the addition was complete, the reaction was continued at -77 to -79 °C for 1.8 to 2.2 h. Under nitrogen atmosphere, a tetrahydrofuran solution of dimethyl borofluoride was slowly injected into the reaction system, and then the temperature was slowly raised to room temperature. The reaction was carried out at room temperature for 11 to 13 h. After the reaction was completed, the target product was obtained by extraction, drying, filtration, concentration and purification.

4. The preparation method according to claim 2 or 3, characterized in that: The molar ratio of the bromoarylamine precursor to n-butyllithium and dimethylboron fluoride is (0.9-1.1):(0.9-1.1):(1.4-1.6).

5. The preparation method according to claim 3, characterized in that: The molar concentration of the tetrahydrofuran solution of the bromoaryl amine precursor is 0.09-0.11 mol / L; the molar concentration of the tetrahydrofuran solution of the dimethyl boron fluoride is 0.14-0.16 mol / L.

6. The preparation method according to claim 2, characterized in that: The method for preparing the bromoaryl amine precursor is as follows: 2-bromo-6-naphthylamine is used as the starting material, and it is reacted with iodobenzene or 4-methoxyiodobenzene respectively via Ullmann coupling reaction in the presence of a copper catalyst under alkaline conditions and an inert atmosphere.

7. The preparation method according to claim 6, characterized in that: The preparation method of the bromoaromatic amine precursor is as follows: 2-bromo-6-naphthylamine, cuprous iodide, 1,10-phenanthroline and potassium hydroxide are added, followed by nitrogen purging and the addition of iodobenzene or 4-methoxyiodobenzene, and anhydrous toluene. The reaction system is heated to 128-132℃ and reacted for 11.5-12.5 h. After the reaction is completed, the reaction system is cooled to room temperature, and then the bromoaromatic amine precursor is obtained by extraction, drying, filtration, concentration and separation purification.

8. The preparation method according to claim 7, characterized in that: The molar ratio of 2-bromo-6-naphthylamine, cuprous iodide, 1,10-phenanthroline, and potassium hydroxide is (0.9-1.1):(0.9-1.1):(0.9-1.1):(19-21); the molar ratio of 2-bromo-6-naphthylamine to iodobenzene or 4-methoxyiodobenzene is (0.9-1.1):(9-11); and the mass-to-volume ratio of 2-bromo-6-naphthylamine to anhydrous toluene is 1 g:50-55 mL.

9. The application of the naphthalene derivative of claim 1 in organic light-emitting devices, fluorescence sensing, and fluorescence imaging.

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