A naphtholactide-indole derivative with AIE properties, preparation method and application thereof

Abstract

The present invention provides a preparation of a naphtholactimide-indole derivative exhibiting anti-influencing (AIE) properties, the structure of which is shown in Formula (II): In Formula (II), R1 is H and OMe, and R2 is OMe, NO2, and Ph. The compound is synthesized using 1,8-naphtholactim and a 3,3-dimethyl-2-styrylindole derivative as raw materials via a Lewis acid-catalyzed reaction. The naphtholactimide-indole derivative provided by the present invention is orange in sunlight, exhibits excellent photostability, and exhibits a pronounced AIE effect. It can be applied in luminescent materials, inkless writing, and anti-counterfeiting applications. The preparation method also features readily available raw materials and simple steps.

Description

Technical Field

[0001] The present invention belongs to the field of organic synthesis, and more particularly relates to the preparation of a naphtholactide-indole derivative with AIE properties. Background Art

[0002] In 2001, Academician Tang Benzhong's team discovered the phenomenon of aggregation-induced emission (AIE), whereby the fluorescence intensity of molecules in an aggregated state is significantly higher than that in a dispersed state. This discovery, which is expected to facilitate the widespread practical application of fluorescent materials, has attracted considerable attention. The AIE phenomenon is primarily attributed to restricted intramolecular motion. When the solution concentration increases or the solution is in a solid state, molecular aggregation leads to a significant enhancement in luminescence. AIE materials overcome the luminescence quenching of traditional dye molecules in the solid or aggregated state, and can also emit strong light in the solid state. As a new advanced material with excellent properties, AIE materials have broad application prospects in organic light-emitting diodes, bioimaging, fluorescent probes, and biological probes.

[0003] In the present invention, we innovatively synthesized target compounds based on the condensation of 1,8-naphtholactam and 3,3-dimethyl-2-phenylindole derivatives. This series of compounds has obvious AIE effect, long-wavelength luminescence and large Stokes shift, and the raw materials are easily available, the operation is simple, and the reaction conditions are mild. Summary of the Invention

[0004] The present invention aims to provide a novel functional organic material that is easy to synthesize and has significant AIE properties.

[0005] The purpose of the present invention is achieved through the following technical solutions:

[0006] A functional organic material with AIE properties, wherein the molecular chemical structure of the material is shown in formula (II), wherein R1 is any one of H and OMe, and R2 is any one of OMe, Ph, and NO2.

[0007] .

[0008] A method for synthesizing a functional organic material with AIE properties, comprising the following synthesis path:

[0009] .

[0010] In formula (I) and formula (II), R1 is any one of H and OMe, and R2 is any one of OMe, Ph, and NO2.

[0011] The synthesis steps of compounds D1-D4 are as follows:

[0012] 1,8-Naphtholactimide (1) and the compound represented by formula (I) are dissolved in toluene. After heating, a catalytic amount of Lewis acid is added. After TLC monitoring, the reaction solution is subjected to reduced pressure rotary evaporation to remove the solvent, dissolved in dichloromethane, and neutralized to pH = 7-8 by adding saturated NaOH solution. The product is then extracted with dichloromethane and dried by rotary evaporation. Finally, the crude product is separated by silica gel column chromatography to obtain functional organic materials D1-D4.

[0013] The functional organic material provided by the present invention has a maximum fluorescence emission wavelength of about 580nm, has a significant AIE effect, good photostability, and high imaging quality. It can be applied to luminescent materials, inkless writing, and anti-counterfeiting fields. At the same time, the preparation method has readily available raw materials and simple steps. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is the hydrogen spectrum of compound D1 obtained in Example 1.

[0015] Figure 2 This is the hydrogen spectrum of compound D2 obtained in Example 5.

[0016] Figure 3 This is the hydrogen spectrum of compound D3 obtained in Example 6.

[0017] Figure 4 This is the hydrogen spectrum of compound D4 obtained in Example 7.

[0018] Figure 5 Fluorescence spectra of D1 in mixed solutions of water and dimethyl sulfoxide at different ratios.

[0019] Figure 6 This is the corresponding picture of D1 under 365 UV light.

[0020] Figure 7 Fluorescence spectra of D2 mixed solutions of water and dimethyl sulfoxide at different ratios.

[0021] Figure 8 This is the corresponding picture of D2 under 365 UV light.

[0022] Figure 9 Fluorescence spectra of D3 in mixed solutions of water and dimethyl sulfoxide at different ratios.

[0023] Figure 10 This is the corresponding picture of D3 under 365 ultraviolet light.

[0024] Figure 11 Fluorescence spectra of D4 in mixed solutions of water and dimethyl sulfoxide at different ratios.

[0025] Figure 12 This is the corresponding picture of D4 under 365 UV light. DETAILED DESCRIPTION

[0026] The embodiments of the present invention will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are only used to illustrate the present invention and should not be regarded as limiting the scope of the present invention.

[0027] Example 1

[0028] 1,8-Naphtholactimide (169.0 mg, 1.0 mmol) and compound C1 (335 mg, 1.2 mmol) were weighed and dissolved in 15 mL of toluene. The mixture was heated and stirred. When the temperature reached 120°C, aluminum chloride (400 mg, 3.0 mmol) was added and refluxed for 4 h. After completion of the reaction as monitored by TLC, the mixture was neutralized with NaOH to a pH of 7-8, extracted with dichloromethane, dried by spin drying, and purified by silica gel column chromatography to obtain an orange solid compound D1 with a yield of 11%. The reaction process was as follows:

[0029] .

[0030] Example 2

[0031] 1,8-Naphtholactimide (169.0 mg, 1.0 mmol) and compound C1 (335 mg, 1.2 mmol) were weighed and dissolved in 15 mL of toluene. The mixture was heated with stirring. When the temperature reached 120°C, boron trifluoride etherate (369 μL, 3.0 mmol) was added and refluxed for 4 h. After completion of the reaction as monitored by TLC, the mixture was neutralized with NaOH to pH 7-8, extracted with dichloromethane, dried by spin drying, and purified by silica gel column chromatography to obtain an orange solid compound D1 with a yield of 15%.

[0032] Example 3

[0033] 1,8-Naphtholactimide (169.0 mg, 1.0 mmol) and compound C1 (335 mg, 1.2 mmol) were weighed and dissolved in 15 mL of toluene. The mixture was heated with stirring. When the temperature rose to 120°C, phosphorus oxychloride (280 μL, 3.0 mmol) was added and refluxed for 4 h. After completion of the reaction as monitored by TLC, the mixture was neutralized with NaOH to pH 7-8, extracted with dichloromethane, dried by spin drying, and purified by silica gel column chromatography to obtain an orange solid compound D1 with a yield of 52%.

[0034] Example 4

[0035] 1,8-Naphtholactimide (169.0 mg, 1.0 mmol) and compound C1 (335 mg, 1.2 mmol) were weighed and dissolved in 15 mL of toluene. After heating and stirring, titanium tetrachloride (330 μL, 3.0 mmol) was added when the temperature rose to 120°C. Reflux was continued for 4 h. After completion of the reaction as monitored by TLC, the mixture was neutralized with NaOH to pH 7-8, extracted with dichloromethane, dried by spin drying, and purified by silica gel column chromatography to obtain an orange solid compound D1 with a yield of 30%.

[0036] Example 5

[0037] Weigh 1,8-naphtholactimide (169.0 mg, 1.0 mmol) and compound C2 (335 mg, 1.2 mmol), add 15 mL of toluene, mix and dissolve, then heat and stir. When the temperature rises to 120°C, add POCl3 (280 μL, 3.0 mmol), and reflux for 4 h. After the reaction is complete as monitored by TLC, neutralize with NaOH to pH = 7-8, extract with dichloromethane, spin dry, and purify by silica gel column chromatography to obtain orange solid compound D2 with a yield of 30%. The reaction process is as follows:

[0038] .

[0039] Example 6

[0040] 1,8-Naphtholactimide (169.0 mg, 1.0 mmol) and compound C3 (353 mg, 1.2 mmol) were weighed and dissolved in 15 mL of toluene. The mixture was heated and stirred. When the temperature reached 120°C, POCl3 (280 μL, 3.0 mmol) was added and refluxed for 4 h. After the reaction was complete as monitored by TLC, the mixture was neutralized with NaOH to a pH of 7-8, extracted with dichloromethane, dried by spin drying, and purified by silica gel column chromatography to obtain an orange solid compound D3 with a yield of 33%. The reaction process was as follows:

[0041] .

[0042] Example 7

[0043] 1,8-Naphtholactimide (169.0 mg, 1.0 mmol) and compound C4 (389 mg, 1.2 mmol) were weighed and dissolved in 15 mL of toluene. The mixture was heated and stirred. When the temperature reached 120°C, POCl3 (280 μL, 3.0 mmol) was added and refluxed for 5 h. After completion of the reaction as monitored by TLC, the mixture was neutralized with NaOH to a pH of 7-8, extracted with dichloromethane, dried by spin drying, and purified by silica gel column chromatography to obtain an orange solid compound D4 with a yield of 62%. The reaction process was as follows:

[0044] .

[0045] Example 8

[0046] Weigh a certain amount of prepared D1~D4, dissolve them in DMSO and prepare a concentration of 10 -2 The mother solution of M is sealed and refrigerated.

[0047] Preparation of the AIE system solution: 0, 0.3, 0.6, 0.9, 1.2, 1.5, 1.8, 2.1, 2.4, 2.7, 2.85, and 2.97 mL of aqueous solution were pipetted, followed by 3, 2.7, 2.4, 2.1, 1.8, 1.5, 1.2, 0.9, 0.6, 0.3, 0.15, and 0.03 mL of dimethyl sulfoxide solution. The mixture was then mixed to a total volume of 3 mL. This resulted in dimethyl sulfoxide-water mixed solutions with water volume fractions of 0, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, and 99%, respectively. 9 μL of the stock solution was added to 3 mL of the solution, and the AIE properties of the dye molecule were tested at a concentration of 0.3 mM.

[0048] To study the AIE properties of D1-D4, the dye molecule test concentration was 0.3mM, and the fluorescence spectra were tested in mixed solutions of water and dimethyl sulfoxide with different water volume ratios (water content 0%-99%), as shown in the figure below. Figure 6-12 As shown, dimethyl sulfoxide (DMSO) is a good solvent for dye molecules D1-D4, while water is a poor solvent. When water is added to the benign DMSO solvent, the concentration reaches a certain level, causing the molecules to aggregate and exhibit a pronounced enhanced luminescence (AIE). For example, D1 exhibits almost no fluorescence in pure DMSO, with an emission wavelength around 580 nm. With increasing water content (0-80%), its fluorescence intensity and wavelength do not change significantly. However, when the water content rises to 80-99%, dye D1 emits a strong orange fluorescence. This is because at low concentrations (0-80%), the vinylbenzene rings can rotate, releasing energy via nonradiative transitions, resulting in a lack of luminescence. However, at water content of 80% or above, D1 aggregates, inhibiting the rotation of the vinylbenzene rings and hindering nonradiative transitions, leading to enhanced luminescence and a significant AIE phenomenon.

[0049] The method and explanation of D2-D4 are the same as above.

[0050] The above embodiments are merely preferred technical solutions of the present invention and should not be construed as limiting the present invention. The embodiments and features in the embodiments of this application may be arbitrarily combined with each other unless they conflict. The scope of protection of the present invention shall be the technical solutions described in the claims, including equivalent alternatives to the technical features of the technical solutions described in the claims. Equivalent alternatives and improvements within this scope are also within the scope of protection of the present invention.

Claims

1. A naphtholactide-indole derivative with AIE properties, characterized in that: The structural formula is shown in Formula II, wherein R1 is any one of H and OMe, and R2 is any one of OMe and NO2; 。 2. A naphtholactide-indole derivative with AIE properties, characterized in that: The structural formula is 。 3. A method for preparing a naphtholactide-indole derivative having AIE properties, characterized in that: Its synthesis method comprises the following steps: 1,8-naphtholactimide 1 and the compound of formula I were dissolved in toluene. After heating, a catalytic amount of Lewis acid was added. After TLC monitoring of the reaction completion, the reaction solution was subjected to vacuum rotary evaporation to remove the solvent, dissolved in dichloromethane, and neutralized with NaOH solution to pH = 7-8. The solution was then extracted with dichloromethane and dried. Finally, the crude product was separated by silica gel column chromatography to obtain an orange solid compound II. The reaction equation is as follows: ； The compound shown in formula I is one of the compounds shown in formulas C1-C4. 。 4. The method for preparing a naphtholactide-indole derivative having AIE properties according to claim 3, wherein: In the synthesis step, the Lewis acid is any one of aluminum chloride, boron trifluoride ethyl ether, phosphorus oxychloride, and titanium tetrachloride.

5. The method for preparing a naphtholactide-indole derivative having AIE properties according to claim 3, wherein: In the synthesis step, the molar ratio of 1,8-naphtholactam, the compound represented by formula I and the Lewis acid is 1:1.2:

3.

6. The method for preparing a naphtholactide-indole derivative having AIE properties according to claim 3, wherein: The reflux temperature of the synthesis step is 120° C., and the reflux time is 4-5 h.

7. The method for preparing a naphtholactide-indole derivative having AIE properties according to claim 3, wherein: In the synthesis step, the order of adding materials is the compound shown in formula I, 1,8-naphtholactim, toluene, and Lewis acid.

8. The method for preparing a naphtholactide-indole derivative having AIE properties according to any one of claims 3 to 7, characterized in that: The structural formula of the prepared naphtholactam-indole derivative is selected from any one of the following: 。 9. Use of the naphtholactide-indole derivative with AIE properties prepared according to the method of claim 8 in realizing aggregation-induced emission in a mixed solution of dimethyl sulfoxide and water.

10. An aggregation-induced emission fluorescent dye, characterized in that: The fluorescent dye includes a naphtholactide-indole derivative with AIE properties prepared by the method according to claim 8.

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