Preparation method and application of tetraphenyl cyclopentadienone-based fluorescent material

Abstract

The invention belongs to the field of organic photoelectric materials, and discloses a preparation method and application of a tetraphenyl cyclopentadienone-based fluorescent material. The fluorescent molecule is constructed by constructing different donor units with triphenylamine and tetraphenylethylene based on tetraphenylcyclopentadienone. The fluorescent material has the following structures I and II: four triphenylamine structures or tetraphenyl ethylene structures are introduced into tetraphenyl cyclopentadienone to construct the fluorescent material. As a conjugation effect exists between double bonds of carbonyl and double bonds on a ring, cyclopentadienone can form a resonance structure. Therefore, electrons are more uniformly distributed in molecules, the stability of the molecules is enhanced, and the reaction activity of the molecules is also influenced. Benefited from the introduction of a molecular rotor, the fluorescent property is researched. A thought is provided for the design of the molecules.

Description

Technical Field

[0001] This invention belongs to the field of organic optoelectronic materials, and specifically relates to the preparation and application of a class of fluorescent materials based on tetraphenylcyclopentadienone. Background Technology

[0002] In 2001, Tang et al. reported a novel photophysical phenomenon: organic molecules do not emit light in their solution, but exhibit high luminescence in their aggregated state (whether in the solid state or as nanoparticles). This behavior was named aggregation-induced emission (AIE). AIE biosensors are considered very promising LED emitters; therefore, in recent years, many blue and deep blue AIE biosensors with good device efficiency have been developed through precise control of the conjugation degree of the emitter. However, to date, there are few reports of AIE molecules with good LED performance. Therefore, through precise molecular design, it is possible to develop new frameworks for blue / deep blue AIE molecules with excellent OLED performance.

[0003] Thiol was the first discovered AIE (Alternating Electron Emission) emitter. Due to its remarkable properties, a series of thiophene-based AIE emitters have been developed and applied in OLEDs as biological probes, chemical sensors, and light emitters. Benefiting from the Si-containing conjugated ring with σ*-π* conjugation effect formed by the σ* orbitals of the outer ring Si-C bond and the π* orbitals of the butadiene segment, thiophene derivatives exhibit high electron affinity and fast electron mobility, resulting in very high LED performance, with an external quantum efficiency reaching 8%, exceeding the theoretical limit.

[0004] Since the 1930s, tetraarylcyclopentadienones (TACPDs) have been synthesized and their properties explored. Their most striking characteristic is their intense color, ranging from deep maroon to velvety deep purple, and almost black. This darkening likely prompted the first photophysical studies, where the goal was to link changes in aromatic ring substituents to changes in absorption spectra. This invention is based on the fluorescent molecules of tetraphenylcyclopentadienones, preparing two fluorescent molecules and investigating their AIE properties. Summary of the Invention

[0005] To address the above issues, a method for synthesizing a class of fluorescent molecules based on tetraphenylcyclopentadienone will be designed. Tetraphenylcyclopentadienone will be prepared by cyclization of a haloalkane under alkaline conditions, with bromine attached to the 2, 3, 4, and 5 positions. Two fluorescent molecules will then be synthesized via a Suzuki reaction.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a method based on tetraphenylcyclopentadienone fluorescent molecules, the preparation method of which includes the following steps:

[0007] In a nitrogen atmosphere, bromine-containing tetraphenylcyclopentadienone, triphenylamine borate, and tetraphenyl styrene borate were added to a reactor in a molar ratio of 1:6. Toluene, ethanol, and water were added as solvents, and tetraphenylphosphine palladium was added as a catalyst. The mixture was stirred with a magnetic stirrer until dissolved. o The reaction was carried out at C for 12 h. After the reaction was completed, the solvent was removed by vacuum distillation to obtain the crude product, which was then purified by column chromatography to obtain the target compound.

[0008] The structure is:

[0009]

[0010] Beneficial effects of this invention:

[0011] 1. This invention synthesizes a class of fluorescent molecular materials based on tetraphenylcyclopentadienone.

[0012] 2. The fluorescent molecular material provided by this invention uses tetraphenylcyclopentadienone as the acceptor to construct a fluorescent molecule with triphenylamine and tetraphenylethylene, and its AIE characteristics are measured.

[0013] 3. The organic molecular stimulus response provided by this invention has few synthesis steps, a simple method, and readily available raw materials. Attached Figure Description

[0014] Figure 1 A and B are the absorption spectra of CPD-01 and CPD-02, respectively;

[0015] Figure 2 A and B are the fluorescence spectra of CPD-02 with different water contents and the linear relationship between the ratio of molecular emission peak intensities and different water contents, respectively.

[0016] Figure 3 The NMR spectrum of CPD-02; Detailed Implementation

[0017] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings, so that those skilled in the art can better understand the advantages and features of the present invention, thereby making a clearer definition of the scope of protection of the present invention. The embodiments described in this invention are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0018] Example 1:

[0019] Preparation of CPD-01:

[0020]

[0021] Synthetic route of CPD-01

[0022] Synthesis of CPD-01: Under a nitrogen atmosphere, bromine-containing tetraphenylcyclopentadienone (0.20 g), triphenylamine 4-borate (0.8 g), tetra(triphenylphosphine)palladium (0.025 g), and potassium carbonate (0.09 g) were added to 30 mL of a mixed solvent of toluene, ethanol, and water in an 8:1:1 ratio. The reaction was carried out at 90 °C for 12 h. After the reaction was completed, the system was cooled, concentrated under reduced pressure, and separated by silica gel column chromatography to obtain a yellow solid product (0.2 g, yield 60%).

[0023] Example 2:

[0024] Preparation of CPD-02:

[0025]

[0026] Synthetic route of CPD-02

[0027] Synthesis of CPD-02: Under a nitrogen atmosphere, bromine-containing tetraphenylcyclopentadienone (0.20 g), 4-boronate tetraphenylethylene (0.8 g), tetra(triphenylphosphine)palladium (0.025 g), and potassium carbonate (0.09 g) were added to 30 mL of a mixed solvent of toluene, ethanol, and water in an 8:1:1 ratio. The reaction was carried out at 90 °C for 12 h. After the reaction was complete, the system was cooled, concentrated under reduced pressure, and separated by silica gel column chromatography to obtain a yellow solid product (0.2 g, yield 60%). The NMR structure is shown below. Figure 3 As shown.

[0028] The structural characterization data of the obtained product are shown below:

[0029] 1 H NMR (500 MHz, CDCl3) δ 7.49–7.34 (m, 27H), 7.19–7.02 (m, 56H), 6.94 (d, J = 8.1 Hz, 4H), 6.84–6.81 (m, 5H).

[0030] Example 3:

[0031] Absorption spectral characterization of fluorescent molecular materials CPD-01 and CPD-02

[0032] Figure 1 A and Figure 1 B shows the absorption spectra of materials CPD-01 and CPD-02 obtained in Examples 1 and 2 in THF. The maximum absorption wavelength of CPD-01 in THF solution is 451 nm, while that of CPD-02 is 323 nm.

[0033] Example 4:

[0034] Fluorescence characterization of CPD-02 with different water contents

[0035] Figure 2 The images show the fluorescence spectra of CPD-02, the material obtained in Example 2, at different water contents at room temperature. Figure 2 A represents the emission spectra of CPD-02 material at different water contents at room temperature. Figure 2 B represents the linear relationship between the ratio of molecular emission peak intensities of CPD-02 and different water contents.

[0036] Example 5

[0037] Attached figures for CPD-01 and CPD-02.

Claims

1. A method for preparing a class of fluorescent materials based on tetraphenylcyclopentadienone and their applications, characterized by the following molecular features: 。 2. The preparation method and application of a type of tetraphenylcyclopentadienone-based fluorescent material according to claim 1, characterized in that: Tetraphenylcyclopentadienone was prepared by cyclization of haloalkanes under alkaline conditions, with bromine attached to the 2, 3, 4, and 5 positions. Two fluorescent molecules were then synthesized via the Suzuki reaction. The introduction of the molecular rotor endowed structure II with AIE properties, which has potential applications in OLED devices.

3. The preparation method and application of a type of tetraphenylcyclopentadienone-based fluorescent material according to claim 1, characterized in that: Its fluorescence spectra with different water contents show certain AIE characteristics.

4. The preparation method and application of a type of tetraphenylcyclopentadienone-based fluorescent material according to claim 1, characterized in that: The molecular structure of tetraphenylcyclopentadienone contains a five-membered ring with two carbon-carbon double bonds and a carbonyl (C=O) group; this structure gives it a certain degree of unsaturation and special chemical properties; the introduction of a molecular rotor gives it a certain twisted structure, which in turn gives it certain fluorescent properties.

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