A D-π-A type triarylboron naphthalene derivative with bistable emission characteristics and a preparation method and application thereof

Abstract

This invention provides a D-π-A type triarylborane naphthalene derivative with dual-state emission characteristics, its preparation method, and its application, belonging to the field of carbocyclic compound technology. The general structural formula of the naphthalene derivative is shown in Formula I, where Ar is phenyl or p-methoxyphenyl. The preparation method of the naphthalene derivative involves lithiation of a bromoaryl amine precursor with n-butyllithium under an inert atmosphere, followed by quenching with dimethylboron fluorine to obtain the corresponding naphthalene derivative. The bromoaryl amine precursor is 2-bromo-6-( N , N '-Diphenylamino)naphthalene or 2-bromo-6-[ N , N '-Di(4-methoxyphenyl)amino]naphthalene. The compounds of this invention maintain high fluorescence quantum yields in a variety of solvents and exhibit strong luminescence in solid-state applications (powders and films), making them high-performance DSE materials.

Description

Technical Field

[0001] This invention belongs to the field of carbocyclic compound technology, specifically relating to a D-π-A type triaryroborane naphthalene derivative with dual-state emission characteristics, as well as the preparation method of this type of compound and its application in organic light-emitting devices, fluorescence sensing and fluorescence imaging. Background Technology

[0002] Organic fluorescent materials, as an important class of functional materials, have been widely used in fields such as bioimaging, information storage, photothermal diagnostics, biosensing, and organic light-emitting diodes (OLEDs). Traditional organic fluorescent molecules typically possess a rigid planar π-conjugated framework, which is beneficial for increasing the radiative transition probability between the ground state (S0) and the first excited state (S1), thus achieving high fluorescence quantum efficiency in dilute solutions. However, such planar molecules often experience severe intermolecular π-π stacking when aggregated or in the solid state, leading to significant fluorescence quenching, known as aggregation-induced quenching (ACQ). This effect severely limits the application of organic fluorescent materials in solid-state devices. To overcome the ACQ problem, researchers proposed the concept of aggregation-induced emission (AIE), which introduces multiple non-coplanar rotatable π structural units into the molecule to suppress π-π stacking in the solid state, thereby achieving strong fluorescence in aggregated or solid-state conditions. However, in dilute solutions, AIE molecules exhibit significantly enhanced nonradiative transitions due to the free rotation and vibration of multiple rotatable π structural units, typically resulting in strong luminescence only in the solid state, with weak or almost no luminescence in solution. Therefore, it is evident that most ACQ-type and AIE-type molecules can only exhibit high fluorescence efficiency in one of two states: dilute solution or solid state, significantly limiting their applications. In recent years, dual-state emission (DSE) fluorescent molecules exhibiting high luminescence efficiency in both solution and solid states have attracted widespread attention. DSE molecules hold promise for bridging the gap between ACQ-type and AIE-type fluorescent molecules, enabling compatible applications in both dispersed and aggregated states. Current strategies for achieving DSE properties largely rely on constructing twisted configurations and increasing molecular rigidity, such as introducing large-volume substituents into the backbone or constructing complex polycyclic aromatic ring twisted structures. These designs often involve cumbersome synthetic steps and complex molecular structures, hindering large-scale preparation and further promotion of the structural systems.

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

[0004] There are several D-π-A type triaryrhodium compounds based on BMes2 disclosed in the prior art, and four typical structures are as follows:

[0005] ;

[0006] It is evident that the fluorescence quantum yield of the aforementioned D-π-A structure luminescent organisms based on BMes2, regardless of whether the skeleton is simple or complex twisted, is low. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a D-π-A type triarylborn naphthalene derivative with dual-state emission characteristics, its preparation method, and its applications. By introducing an electron acceptor dimethyl boron (BMes2) group and an electron donor diarylamine (NAr2) group at the 2,6 positions of the rigid naphthalene ring, the resulting molecule exhibits excellent fluorescence quantum efficiency in both dilute solutions and solids (including powders and films), thereby achieving highly efficient dual-state emission characteristics.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] A D-π-A type triarylbornaphthalene derivative exhibiting dual-state emission characteristics, the general structural formula of which is:

[0010] ;

[0011] The Ar is phenyl or p-methoxyphenyl.

[0012] In the general formula structure:

[0013] The π-bridged unit is centered on the naphthalene ring;

[0014] A dimethyl boron (BMes2) acceptor group is attached to the 2-position of the naphthalene ring;

[0015] A diarylamine (NAr2) donor group is attached to the 6-position of the naphthalene ring, specifically a diphenylamine (NPh2) group or... N , N '-Di(4-methoxyphenyl)amine (N OMe Ph2 group.

[0016] The preparation method of the naphthalene derivative involves lithiation of a bromoaryl amine precursor with n-butyllithium under an inert atmosphere, followed by quenching with dimethylboron fluorine to obtain the corresponding naphthalene derivative. The bromoaryl amine precursor is 2-bromo-6-( N , N '-Diphenylamino)naphthalene or 2-bromo-6-[ N , N '-Di(4-methoxyphenyl)amino]naphthalene.

[0017] The method for preparing the naphthalene derivative is as follows: the temperature of the tetrahydrofuran solution of the bromoarylamine precursor is lowered to -77 to -79°C, and n-butyllithium is slowly added dropwise under nitrogen protection. After the addition is complete, the reaction is continued at -77 to -79°C for 1.8 to 2.2 hours. Under nitrogen atmosphere, a tetrahydrofuran solution of dimethyl borofluoride is slowly injected into the reaction system, and then the temperature is slowly raised to room temperature. The reaction is carried out at room temperature for 11 to 13 hours. After the reaction is completed, the target product is obtained by extraction, drying, filtration, concentration, and purification.

[0018] 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).

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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).

[0023] The molar ratio of 2-bromo-6-naphthylamine to iodobenzene or 4-methoxyiodobenzene is (0.9-1.1): (9-11).

[0024] The mass-to-volume ratio of 2-bromo-6-naphthylamine to anhydrous toluene is 1 g: 50-55 mL.

[0025] The application of the naphthalene derivative in organic light-emitting devices, fluorescence sensing, and fluorescence imaging.

[0026] This invention, while maintaining the rigid planar structure of the naphthalene ring, effectively suppresses intermolecular π-π stacking in the solid state by introducing large-volume BMes2 and NAr2 groups at the 2,6 positions, thereby achieving efficient dual-state emission in both solution and solid states.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] (1) Simple structure and short synthetic route: D-π-A type triaryroborane naphthalene derivatives can be obtained by relying only on Ullmann coupling and simple borylation steps, avoiding the construction of complex twisted skeletons, and are suitable for large-scale preparation and structural expansion.

[0029] (2) Excellent dual-state emission performance: The compounds of this invention maintain high fluorescence quantum yields in a variety of solvents and still exhibit strong luminescence in solid-state (powder and thin film) forms, belonging to high-performance DSE materials. The fluorescence quantum efficiency of BNPh-Nap prepared in this invention is 0.97 in cyclohexane, 0.71 in BNOPh-Nap in cyclohexane, 0.67 in BNPh-Nap powder, 0.91 in BNOPh-Nap powder, 0.51 in BNPh-Nap thin film, and 0.99 in BNOPh-Nap thin film.

[0030] (3) Wide range of applications: Since it has both efficient light emission in solution and solid state, the compound of the present invention is suitable for various applications that require cross-phase use, such as organic light-emitting diodes, sensing, anti-counterfeiting and bio-imaging, and has good application prospects. Attached Figure Description

[0031] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. Exemplary embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0032] Figure 1 This is a schematic diagram of the molecular structures of the compounds BNPh-Nap and BNOPh-Nap of the present invention;

[0033] (a) is a schematic diagram of the molecular structure of BNPh-Nap, and (b) is a schematic diagram of the molecular structure of BNOPh-Nap.

[0034] Figure 2 This is a schematic diagram showing the optimized configurations of the compounds BNPh-Nap and BNOPh-Nap in the ground and excited states of this invention.

[0035] Where (a) is a schematic diagram of the optimized configuration of BNPh-Nap in the ground state and excited state, and (b) is a schematic diagram of the optimized configuration of BNOPh-Nap in the ground state and excited state;

[0036] Figure 3 The images show the spectra, Lippert-Mataga plots, and fluorescence quantum yield histograms of the compounds BNPh-Nap and BNOPh-Nap of this invention.

[0037] (a) shows the UV-Vis absorption and fluorescence spectra in cyclohexane, (b) shows the Lippert-Mataga plot, and (c) shows the fluorescence quantum yield histogram in different solvents.

[0038] Figure 4 The fluorescence spectra of compounds BNPh-Nap and BNOPh-Nap in different solvents are shown below.

[0039] Where (a) is the fluorescence spectrum of BNPh-Nap in different solvents, and (b) is the fluorescence spectrum of BNOPh-Nap in different solvents;

[0040] Figure 5 The UV-Vis absorption and fluorescence spectra of the compounds BNPh-Nap and BNOPh-Nap in the solid state are shown below.

[0041] Figure 6 The absolute quantum efficiency spectrum of the compound BNPh-Nap of this invention is shown in the powder test spectrum.

[0042] Figure 7 The image shows the absolute quantum efficiency of the thin film of the compound BNPh-Nap of this invention.

[0043] Figure 8 The absolute quantum efficiency spectrum of the compound BNOPh-Nap of this invention is shown in the powder test spectrum.

[0044] Figure 9 The image shows the absolute quantum efficiency of the thin film of the compound BNOPh-Nap of this invention.

[0045] Figure 10 The 1H NMR spectrum of the compound BrNOPh-Nap of this invention;

[0046] Figure 11 The 1H NMR spectrum of the compound BNPh-Nap of this invention;

[0047] Figure 12 The carbon NMR spectrum of the compound BNPh-Nap of this invention;

[0048] Figure 13The 1H NMR spectrum of the compound BNOPh-Nap of this invention;

[0049] Figure 14 The carbon NMR spectrum of the compound BNOPh-Nap of this invention;

[0050] Figure 15 This is a synthetic route diagram for the naphthalene derivatives of this invention. Detailed Implementation

[0051] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0052] Example 1: Preparation of BrNPh-Nap

[0053] A magnetic flux was added to a dry 250 mL Schlenk tube, along with 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. The reaction mixture was heated to 130 °C and reacted for 12 h. After the reaction was complete, the mixture was cooled to room temperature and 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 =0.30), to give a white solid product BrNPh-Nap (1.28 g, 3.43 mmol), with a yield of 78%.

[0054] Example 2: Preparation of BrNOPh-Nap

[0055] The preparation method of BrNOPh-Nap is similar to that of BrNPh-Nap, except that 4-methoxyiodobenzene is used instead of iodobenzene, and the amount of raw materials added is slightly adjusted. The raw materials and their amounts are as follows:

[0056] 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) were purified by silica gel column chromatography (petroleum ether: dichloromethane = 2:1). Rf Purification was performed using a solvent (e.g., 0.20 g) to give a white solid product BrNOPh-Nap (1.26 g, 2.9 mmol), with a yield of 58%. 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).

[0057] Example 3: Preparation of BNPh-Nap

[0058] 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), with a yield of 73%. 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 38 BN: 544.3170; Found544.3163.

[0059] Example 4: Preparation of BNOPh-Nap

[0060] 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); 13C 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.

[0061] Example 5: Structural Features

[0062] 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.

[0063] 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

[0064]

[0065] Example 6: Optical Properties of Solutions

[0066] 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 ).

[0067] 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.

[0068] 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.

[0069] 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.

[0070] Example 7: Optical Properties of Solid State

[0071] 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.

[0072] 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.

[0073] 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.

[0074] 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. OMePh2 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.

[0075] Table 2: Photophysical properties of BNPh-Nap and BNOPh-Nap in different solutions and solids

[0076]

[0077] 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: ； Ar is 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 '-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 preparation method of the bromoaryl amine precursor is to use 2-bromo-6-naphthylamine as the starting material, and react it with 4-methoxyiodobenzene through 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 then 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 4-methoxyiodobenzene is (0.9-1.1): (9-11). 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 and fluorescence sensors, wherein the application is not for the purpose of diagnosing or treating diseases.

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