A photochromic cyano-containing fluorescent dye and preparation thereof

Abstract

This invention relates to a simple method for preparing photochromic triphenylacrylonitrile compounds. The readily synthesizable 2-(4-bromophenyl)-3,3-diphenylacetonitrile acrylonitrile is reacted with diphenyl disulfide to obtain a sulfide fluorescent compound, which is then oxidized using different oxidants to obtain sulfoxide or sulfone fluorescent compounds. All synthesized fluorescent compounds exhibit photochromic properties in solution. The sulfoxide-containing triphenylacrylonitrile compounds can be recrystallized using different methods to obtain crystals with two conformations, only one of which exhibits photochromic properties. This method is simple to operate and has high yield. The crystal structure of the compounds prepared by this method is beneficial for studying the relationship between solid conformation and photostimulation, and can be applied to memory storage materials.

Description

Technical Field

[0001] This invention relates to the field of organic color-changing fluorescent materials, and more particularly to triphenylacrylonitrile photochromic fluorescent compounds and their preparation methods. Background Technology

[0002] Among numerous stimulus-responsive materials, photochromic materials have been widely used in fields such as information storage, smart windows, and trademark anti-counterfeiting due to their reversible structural changes and the precision and remote controllability of light stimulation [1,2]. Therefore, the construction and controllable adjustment of the properties of novel solid-state photochromic materials are of great significance for expanding the applications of this type of compound.

[0003] Current research focuses primarily on photochromic materials such as spiropyrans, azo compounds, diarylethenes, and spiroxazines. Fluorescent switches, which use fluorescence as the output signal to express the switching state, offer advantages such as high sensitivity and fast response, while minimizing the destruction of recorded information. Therefore, the development of solid-state photochromic materials using fluorescence as a low-destructive readout signal is a current research hotspot. Triarylethene compounds have been reported to exhibit photochromic properties in solution, thin film, and crystalline states. However, current technologies lack methods for controlling the photochromic properties of these compounds through simple heating or solvent fumigation. Summary of the Invention

[0004] The purpose of this invention is to provide a simple method for synthesizing triphenylacrylonitrile compounds with photochromic properties.

[0005] The technical solution of the present invention is as follows:

[0006] The molar ratio of substrate to oxidant is 1:0.8-1:5.

[0007] The oxidation reaction temperature is 0~30 ℃.

[0008] The oxidation reaction time is 0.1-24 h.

[0009] The oxidizing agent is m-chloroperoxybenzoic acid.

[0010] The purity of m-chloroperoxybenzoic acid is 75% or 85%.

[0011] The structure of the compound was determined by nuclear magnetic resonance and high-resolution mass spectrometry.

[0012] To further illustrate the features and technical content of the present invention, the accompanying drawings are provided for reference and explanation. Attached Figure Description

[0013] Figure 1 This is a comparison of the ultraviolet absorption spectra of the compound solution before and after photochromism in the embodiments of the present invention.

[0014] Figure 2 The image shows the fluorescence emission pattern of the compound crystals produced in the example. Detailed Implementation

[0015] The following examples will help to further understand the present invention, but the scope of the present invention is not limited thereto.

[0016] Example

[0017] (1) Synthesis of intermediate phenyltriphenylacrylonitrile sulfide

[0018]

[0019] Under nitrogen atmosphere, synthesized bromotriphenylacrylonitrile (3.6 g, 10 mmol) and anhydrous THF (150 mL) were added to a 100 mL three-necked flask. When the reaction system temperature dropped to -78 °C, n-butyllithium (10 mL, 1.6 mol / L, 16 mmol) was slowly added dropwise. After continuing the reaction at -78 °C for 0.5 h, diphenyl disulfide (2.62 g, 12 mmol) was added. One hour later, the reaction system temperature was raised to room temperature, and the reaction solution was extracted with 150 mL of dichloromethane (3 × 50 mL). The collected organic layer was washed three times with 100 mL of saturated brine solution, dried over anhydrous Na₂SO₄, and the crude product obtained after solvent removal was purified by silica gel column chromatography (petroleum ether (60–90 °C) as eluent) to give an intermediate (3.03 g, 78% yield, white solid).

[0020] [2] Synthesis of the target product

[0021]

[0022] The intermediate product (416 mg, 1.14 mmol) and dichloromethane (20 mL) were added to a 50 mL round-bottom flask. When the system temperature dropped to 0 °C, 276 mg of m-chloroperoxybenzoic acid (75%, 1.71 mmol) was added to the reaction system in five portions. After the addition was complete, the reaction was allowed to proceed for 12 hours. Then, 10 mL of saturated sodium bicarbonate solution was added to the reaction system. The organic phase was extracted with dichloromethane solution (3 × 20 mL), dried over anhydrous sodium sulfate, and the solvent was removed under reduced pressure. The crude product was further purified by column chromatography (elution: petroleum ether (60–90 °C) / ethyl acetate = 5:1, v / v) to obtain the target product (360 mg, yield 89%). 1 H NMR (400 MHz, CDCl3) δ 7.56 (d, J= 3.8 Hz, 2H, Ar-H),7.45 – 7.18 (m, 13H, Ar-H), 7.08 (dd, J = 26.0, 5.5 Hz, 4H, Ar-H), 6.88 (s,1H). HR-MS (ESI + ) m / z Calcd for C 26 H 20 SO [M+H] + 381.1308; found 381.1299.

[0023] The UV absorption spectra of the product compound in this embodiment before and after photochromism are as follows: Figure 1 As shown, the crystal fluorescence emission pattern of the compound is as follows: Figure 2 As shown.

Claims

1. A triphenylpropene cyanopic photochromic fluorescent compound characterized by, The structural general formula is as follows: wherein X = SO, SO2.

2. The method of synthesis of triphenylpropene cyanopic fluorescent compound as claimed in claim 1, wherein: The preparation method comprises the following steps: ① 2-(4-bromophenyl)-3,3-diphenylacetonitrile propynitrile is reacted with diphenyl disulfide, and post-treatment is performed to obtain an intermediate product (a sulfide compound); ； ② the sulfide compound is dissolved in a solvent, 0.85-5 equivalents of an oxidizing agent are used, and post-treatment is performed to obtain a sulfoxide or sulfone compound; ； 。 3. The method for synthesizing a photochromic fluorescent compound according to claim 2, characterized in that: The molar ratio of the substrate to the oxidizing agent is 1:0.8-1:5; the oxidation reaction temperature is 0-30 ℃; the oxidation reaction time is 0.1-24 h; and the oxidizing agent is meta-chloroperoxybenzoic acid.

4. The method for synthesizing a photochromic fluorescent compound according to claim 3, characterized in that: The purity of the selected meta-chloroperoxybenzoic acid is 75% or 85%.

5. The triphenyl propynitrile photochromic fluorescent compound in claim 1 is applied to preparation of light control materials or anti-counterfeiting products.

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