A visible light-modulated fluorescent brightening type diarylethene organic compound, its preparation method and application

Abstract

This invention discloses a visible-light-controlled, high-fluorescence-quantum-yield, fluorescently lit diarylethene organic compound and its preparation method. The structure of the fluorescently lit diarylethene organic compound is shown in general formula (1), where R1 represents an aromatic functional group. All fluorescently lit diarylethene photochromic materials of this invention can achieve visible-light-driven open-ring to closed-ring conversion and exhibit extremely high fluorescence quantum yield in the closed-ring form.

Description

Technical Field

[0001] This invention relates to photochromic materials, and particularly to a novel visible light-driven, high fluorescence quantum yield, fluorescence-illuminated diarylethene photochromic material. Background Technology

[0002] Fluorescent turn-on diarylethylene molecules, due to their unique photophysical properties of being non-fluorescent in the open-ring state and fluorescent in the closed-ring state, have been widely used in sensing, gating, anti-counterfeiting, and super-resolution microscopy of biological organisms in recent years, possessing broad commercial value. However, most currently available fluorescent turn-on diarylethylene molecules, whether in the solid or solution state, absorb only in the ultraviolet region, meaning that these molecules can only undergo the transition from open-ring to closed-ring state under ultraviolet light irradiation. Furthermore, the closed-ring fluorescence quantum yield of most fluorescent turn-on diarylethylene molecules is generally low, limiting their application in super-resolution fluorescence imaging. This is because, on the one hand, ultraviolet light affects the stability of the molecules themselves; prolonged ultraviolet irradiation inevitably leads to uncontrollable photochemical side reactions, resulting in molecular aging. On the other hand, low fluorescence quantum yields increase the signal-to-noise ratio in super-resolution fluorescence imaging of biological organisms, leading to poor imaging results. Therefore, developing fluorescent turn-on diarylethylene molecules with high fluorescence quantum yields for visible light-driven open-ring to closed-ring photocyclization transitions is of great significance. Summary of the Invention

[0003] To address the aforementioned problems in the existing technology, this invention provides a diarylethylene organic compound, its preparation method, and its application in visible light-controlled fluorescent illumination materials. This material can achieve the conversion from an open-ring to a closed-ring form under visible light driving and has a higher fluorescence quantum yield.

[0004] The technical solution of the present invention is as follows:

[0005] A fluorescently lit diarylethene organic compound, the structure of which is shown in general formula (1):

[0006]

[0007] In general formula (1), R1 is a substituted or unsubstituted aryl group, and the substituent on the aryl group is selected from one or more of C1-C4 alkyl, C1-C4 alkoxy, substituted amino, and trifluoromethyl.

[0008] This invention utilizes a strategy of connecting aromatic rings at positions 6 and 6' of an existing fluorescently lit diarylethylene molecular backbone. This strategy can increase the degree of conjugation of the molecule, causing the absorption edge of the open-ring form to redshift to the visible light region, and can also increase the absorption intensity of the closed-ring form (i.e., increase the oscillator intensity). This results in a fluorescently lit diarylethylene photochromic material that can achieve visible light-driven high fluorescence quantum yield.

[0009] Preferably, R1 is a substituted or unsubstituted phenyl group, wherein the substituents on the phenyl group are selected from one or more of C1-C4 alkyl and C1-C4 alkoxy groups.

[0010] As a preferred embodiment, R1 in general formula (1) represents one of the following structures:

[0011]

[0012]

[0013] Preferably, the visible light-driven high fluorescence quantum yield fluorescently lit diarylethylene organic compound is one of the following specific compounds:

[0014]

[0015]

[0016] Preferably, the fluorescently lit diarylethene organic compound is compound 1, 2, or 5, with the following structural formula:

[0017]

[0018]

[0019] This invention also provides a method for preparing the fluorescently lit diarylethene organic compound, comprising:

[0020] Under an inert atmosphere, the iodinated compound and the boric acid compound were dissolved in tetrahydrofuran, and then Pd(PPh3)4 and saturated potassium carbonate solution were added. The mixture of the above reactants was refluxed for 12-24 h. After the reaction mixture was cooled to room temperature, it was extracted with ethyl acetate, the organic phases were combined, dried over anhydrous Na2SO4 and evaporated to dryness. The target product was obtained by silica gel column chromatography.

[0021] The reaction formula is as follows:

[0022]

[0023] Preferably, the molar ratio of the iodinated compound to the borate compound is 1:2.4-2.6, the molar ratio of Pd(PPh3)4 to the borate compound is 0.1:0.9-1.1, and the volume ratio of saturated potassium carbonate solution to tetrahydrofuran is 0.5:0.9-1.1.

[0024] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0025] The compounds of this invention are constructed based on aromatic rings and their derivatives linked to the 6' and 6' positions of the Me-BTTO4 molecular backbone. The connection of the aromatic rings at the 6' and 6' positions leads to a decrease in the HOMO-LUMO band gap in the open-ring state, resulting in a redshift in the absorption spectrum of the open-ring state, with the absorption edge located in the visible light region, thus enabling a visible light-driven photocyclization reaction. Furthermore, the absorption intensity of the closed-ring state is significantly enhanced after the introduction of the aromatic rings, i.e., the oscillator intensity of the molecule increases, thereby enhancing the fluorescence quantum yield. Moreover, all the above results have been verified by density functional theory calculations and experiments, demonstrating that this novel diarylethene molecule has excellent application prospects. Detailed Implementation

[0026] The present invention will now be described in detail with reference to the embodiments.

[0027] Example 1: Synthesis of Compound 1:

[0028] Synthesis route:

[0029]

[0030] In a 50 mL double-necked flask, intermediate iodome-BTTO4 (0.21 g, 0.30 mmol), 2-methylphenylboronic acid (0.10 g, 0.72 mmol), and 10 mL of tetrahydrofuran solution were added sequentially and stirred until dissolved. Then, 5 mL of saturated K₂CO₃ solution and Pd(PPh₃)₄ (0.09 g, 0.08 mmol) were added. The solution was degassed with nitrogen for approximately 15 minutes and then refluxed for 8 hours. After cooling the reaction mixture to room temperature, it was extracted with ethyl acetate, and the combined organic phases were dried over anhydrous Na₂SO₄ and evaporated to dryness. Purification by silica gel column chromatography (DCM / hexane = 1:3) yielded 1 (0.16 g, 85%). 1 H NMR (400MHz, CDCl3): δ[ppm]1.99-1.25(t,6H),2.23-2.27(m,9H),7.30-7.63( m,9H),7.76(d,J=4Hz,3H),7.82(s,1H),7.93(t,J=8Hz,1H),8.22-8.26(m,1H); 13C NMR (100MHz, CDCl3): δ[ppm]146.44,138.90,137.38,137.19,135.30,132.12,130.01,129.86,127.64,12 7.56,126.94,126.67,125.38,125.08,122.77,122.23,121.99,121.94,18.3,15.7,8.61,8.33.HRMS[M+H] + calcd.for C 37 H 30 O4S3:634.1306,found634.1463.

[0031] Example 2: Synthesis of Compound 2:

[0032] Synthesis route:

[0033]

[0034] In a 50 mL double-necked flask, iodomethacin-BTTO4 (0.21 g, 0.30 mmol), 2,6-dimethylphenylboronic acid (0.11 g, 0.72 mmol), and 10 mL of tetrahydrofuran solution were added sequentially and stirred until dissolved. Then, 5 mL of saturated K2CO3 solution and Pd(PPh3)4 (0.09 g, 0.08 mmol) were added. The solution was degassed with nitrogen for approximately 15 minutes and then refluxed for 8 hours. After cooling the reaction mixture to room temperature, it was extracted with ethyl acetate, and the combined organic phases were dried over anhydrous Na2SO4 and evaporated to dryness. Purification by silica gel column chromatography (DCM / hexane = 1:3) yielded 2 (0.16 g, 83%). 1 H NMR (400MHz, CDCl3): δ[ppm]1.92-2.24(m,6H),2.25-2.29(m,15H),7.51-7.62 (m,7H),7.90-7.92(m,2H),7.96(m,2H),8.25-8.27(m,1H),8.41(d,J=4Hz,1H); 13 C NMR (100MHz, CDCl3): δ[ppm]148.42,140.38,140.04,136.42,134.91,132.17,129.98,129.84,128.90,12 7.53,124.84,124.64,123.73,123.09,121.97,121.94,121.82,118.91,18.3,15.7,8.60,8.28.HRMS[M+H] + calcd.for C 39 H34 O4S3:662.1619, found662.1721.

[0035] Example 3: Synthesis of Compound 5:

[0036] Synthesis route:

[0037]

[0038] In a 50 mL double-necked flask, iodomethacin-BTTO4 (0.21 g, 0.30 mmol), 4-methoxyphenylboronic acid (0.11 g, 0.72 mmol), and 10 mL of tetrahydrofuran solution were added sequentially and stirred until dissolved. Then, 5 mL of saturated K2CO3 solution and Pd(PPh3)4 (0.09 g, 0.08 mmol) were added. The solution was degassed with nitrogen for approximately 15 minutes and then refluxed for 8 hours. After cooling the reaction mixture to room temperature, it was extracted with ethyl acetate, and the combined organic phases were dried over anhydrous Na2SO4 and evaporated to dryness. Purification by silica gel column chromatography (DCM / hexane = 1:3) yielded 2 (0.14 g, 80%). 1 H NMR (400MHz, CDCl3): δ [ppm] 1.90-2.22 (m, 6H), 5.82 (d, J = 8Hz, 6H); 7.30-7.61 (m, 9H), 7.76 (d, J = 8Hz, 3H), 7.88-7.90 (m, 1H), 8.15-8.24 (m, 2H); 13 CNMR (100MHz, CDCl3): δ[ppm]148.04,140.59,139.97,136.19,134.87,132.13,130.82,130.00,129.86,12 7.44,124.87,124.77,122.99,122.63,122.37,121.97,121.93,120.16,55.9,55.8,8.59,8.28.HRMS[M+H] + calcd.for C 37 H 30 O6S3:667.1205,found667.1199.

[0039] The vertical absorption energy, oscillator strength, HOMO / LUMO energy level, and band gap between HOMO and LUMO were quantitatively calculated for the open-ring and closed-ring forms of compounds 1, 2, and 5 of this invention, respectively; the maximum emission, fluorescence quantum yield, fluorescence lifetime, and S1 energy level were tested, and the results are shown in Table 1.

[0040] Table 1: Theoretical calculations and experimental data for molecules 1, 2, and 5

[0041]

[0042]

[0043] The above experimental results show that the absorption edges of the open-ring forms of compounds 1, 2 and 5 of this application are located in the visible light region. At the same time, the closed-ring forms have extremely high fluorescence quantum efficiency, which can successfully achieve visible light-driven cycloidization and high fluorescence quantum yield, and have good application prospects.

[0044] While the invention has been disclosed through embodiments and preferred embodiments, it should be understood that the invention is not limited to the disclosed embodiments. Rather, those skilled in the art will appreciate that it is intended to cover various variations and similar arrangements. Therefore, the scope of the appended claims should be consistent with the broadest interpretation to cover all such variations and similar arrangements.

Claims

1. A diarylethylene organic compound, characterized in that, The structure is shown in general formula (1): In general formula (1), R1 represents one of the following structures:

2. The diarylethylene organic compound according to claim 1, characterized in that, Compound 1, 2, or 5 has the following structural formula:

3. The application of a diarylethylene organic compound as described in any one of claims 1 to 2 in the preparation of photochromic materials.

4. The application of the diarylethylene organic compound according to claim 3 in the preparation of photochromic materials, characterized in that, The photochromic material is a visible light-controlled fluorescence illumination type material.

5. An anti-counterfeiting ink, characterized in that, Organic compounds containing diarylethene as described in any one of claims 1 to 2.

6. A method for preparing a diarylethylene organic compound as described in any one of claims 1 to 2, characterized in that, include: Under an inert atmosphere, the iodinated compound and the boric acid compound were dissolved in tetrahydrofuran, and then Pd(PPh3)4 and saturated potassium carbonate solution were added. The mixture of the above reactants was refluxed for 12-24 h. After the reaction mixture was cooled to room temperature, it was extracted with ethyl acetate, the organic phases were combined, dried over anhydrous Na2SO4 and evaporated to dryness. The target product was obtained by silica gel column chromatography. The reaction formula is as follows:

7. The method for preparing the diarylethylene organic compound according to claim 6, characterized in that, The molar ratio of the iodinated compound to the borate compound is 1:2.4-2.6, the molar ratio of Pd(PPh3)4 to the borate compound is 0.1:0.9-1.1, and the volume ratio of saturated potassium carbonate solution to tetrahydrofuran is 0.5:0.9-1.1.

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