A julolidine aggregation-induced emission material, preparation method and application thereof

Abstract

The present invention provides a julolidine aggregation-induced emission material, a preparation method and an application thereof, relating to the technical field of organic aggregation-induced emission materials. The aggregation-induced emission material provided by the present invention is prepared by using 8-hydroxy-9-julolidine aldehyde and m-phenylenediamine as reaction raw materials through a one-step polymerization reaction. Due to the steric hindrance effect of two julolidine groups at the meta-position of the benzene ring in the compound, the planarity within its molecules is reduced, and the intermolecular π-π interaction in the aggregated state is inhibited, endowing it with the AIE property of fluorescence enhancement and having significant application value. At the same time, the molecular material contains two ion interaction sites, namely imine and o-phenol hydroxyl groups, and shows a sensitive "off-on" fluorescence detection signal after complexing with Al<supgt;3+< / supgt>, having high application value. Moreover, its preparation method has the advantages of high yield, simple synthesis process and easy implementation, etc., is suitable for industrial promotion, and creates favorable conditions for the popularization and application of the present julolidine-m-phenylenediamine compound.

Description

Technical Field

[0001] The present invention relates to the technical field of organic aggregation-induced emission materials, and particularly to a julolidine-m-phenylenediamine compound with aggregation-induced fluorescence enhancement, its preparation method and application. Background Art

[0002] Fluorescent compounds have unique advantages in chemical biosensors, optoelectronic devices, etc., and have become one of the current research hotspots and frontier topics. Many organic luminescent materials have high fluorescence quantum yields and excellent fluorescence properties in dilute solutions, but their fluorescence properties are greatly reduced or completely quenched in higher-concentration solutions or solid states, that is, the aggregation-caused quenching (ACQ) phenomenon, which greatly limits the development and application of solid-state fluorescent materials. In 2001, the research group of Professor Ben Zhong Tang at the Hong Kong University of Science and Technology first reported a phenomenon completely opposite to ACQ, that is, the aggregation-induced emission (AIE) phenomenon. AIE molecules emit weak fluorescence or even no fluorescence in the solution state, while emitting strong fluorescence in the solid state or aggregation state. The AIE phenomenon overcomes the problem of aggregation-induced fluorescence quenching and has broad application prospects in solid-state light-emitting devices, biosensing and other fields.

[0003] After more than twenty years of development, great progress has been made in the research on the AIE phenomenon in aspects such as optoelectronic materials, biological science, chemical sensing and the application of stimulus-responsive materials. Among many AIE compounds, tetraphenylethylene derivatives are favored because of their excellent optical properties, easy synthesis, easy functionalization and derivatization, etc., and have become the most commonly used molecules in the research of aggregation-induced emission materials. In addition, in order to meet different functional requirements, many new organic aggregation-induced emission materials have been designed and developed, such as heterocyclic polyenes and their derivatives, triphenylamine derivatives, pyran derivatives and biphenyl derivatives, etc., leading to new developments in a series of fields, covering biological imaging, optoelectronic materials, cancer treatment, intelligent materials and other fields. The julolidine group has the advantages of high photostability and easy structural modification. By substituting and modifying its peripheral sites, a series of fluorescent molecular sensors with different recognition properties and optical transformation mechanisms have been synthesized, but there are few reports on the aggregation-induced emission materials constructed by the julolidine group and m-phenylenediamine. Summary of the Invention

[0004] The technical object of the present invention is to provide a julolidine-m-phenylenediamine compound material with aggregation-induced fluorescence enhancement and easy preparation.

[0005] Another technical object of the present invention is to provide a method for sensitively detecting Al 3+ in water, and this method has the advantages of sensitivity, rapidity, simplicity, easy operation, etc.

[0006] To achieve the above technical objectives, the present invention adopts the following technical solutions:

[0007] A julolidine-m-phenylenediamine Schiff base compound with aggregation-induced emission, and its molecular structure is:

[0008]

[0009] A preparation method of a julolidine-m-phenylenediamine compound with aggregation-induced emission is as follows:

[0010] Under N 2 protection conditions, α mmol of -8-hydroxy-9-julolidine aldehyde and β mmol of m-phenylenediamine are sequentially placed in a round-bottom flask, dissolved with γ mL of absolute ethanol, and then δ μL of glacial acetic acid is added to the above solution. The temperature is raised to reflux and reacted for 3-6 hours; after filtering the reaction mixture, washing with absolute ethanol, and drying, a dark red julolidine-m-phenylenediamine compound is obtained; α:β:γ:δ is 2:1:20:200.

[0011] The preparation reaction formula of the julolidine-m-phenylenediamine compound is:

[0012]

[0013] The present invention has the following technical effects: In this julolidine-m-phenylenediamine compound, the steric hindrance of the two julolidine groups located at the meta-position of the benzene ring reduces the intramolecular planarity and inhibits the π-π interaction between molecules in the aggregated state, making it have the property of enhanced fluorescence by aggregation-induced emission; at the same time, this molecular material contains two ion interaction sites, namely imine and ortho-phenolic hydroxyl. After complexing with Al 3+ its fluorescence emission at 480 nm is significantly enhanced, showing a sensitive "off-on" fluorescence detection signal for Al 3+ and having high application value; the preparation process of the julolidine-m-phenylenediamine compound provided by the present invention has the advantages of mild synthesis conditions, simple preparation process, and low cost, is suitable for industrial implementation, and creates favorable conditions for the popularization and application of this julolidine-m-phenylenediamine compound. Description of the Drawings

[0014] Figure 1 is the ultraviolet absorption spectrum of the julolidine-m-phenylenediamine compound in a mixed solvent of different ratios of THF-H 2 O.

[0015] Figure 2 is the emission spectrum of the julolidine-m-phenylenediamine compound in a mixed solvent of different ratios of THF-H 2 O.

[0016] Figure 3UV absorption spectra of the julolidine-p-phenylenediamine compound in THF-H 2 O mixed solvents with different ratios

[0017] Figure 4 Emission spectra of the julolidine-p-phenylenediamine compound in THF-H 2 O mixed solvents with different ratios

[0018] Figure 5 Fluorescent selective recognition performance of the julolidine-m-phenylenediamine compound for Al 3+ Detailed implementation manners

[0019] A julolidine-m-phenylenediamine compound with aggregation-induced enhancement disclosed by the present invention has a molecular structure as follows:

[0020] ;

[0021] It can be prepared by using 8-hydroxy-9-julolidine aldehyde and m-phenylenediamine as reaction raw materials through a one-step polymerization reaction. The synthesis reaction formula is:

[0022] . Examples

[0023] Under N 2 protection conditions, 2 mmol of 8-hydroxy-9-julolidine aldehyde and 1 mmol of m-phenylenediamine were sequentially placed into a round-bottom flask, dissolved with 20 mL of absolute ethanol, and then 200 µL of glacial acetic acid was added to the above solution. The temperature was raised to reflux for 3 hours. After filtering the reaction mixture, washing with absolute ethanol, and drying, a dark red compound A, 316.3 mg, with a yield of 62.7% was obtained. Examples

[0024] Under N 2 protection conditions, 2 mmol of 8-hydroxy-9-julolidine aldehyde and 1 mmol of m-phenylenediamine were sequentially placed into a round-bottom flask, dissolved with 20 mL of absolute ethanol, and then 200 µL of glacial acetic acid was added to the above solution. The temperature was raised to reflux for 6 hours. After filtering the reaction mixture, washing with absolute ethanol, and drying, a dark red compound B, 327.6 mg, with a yield of 65% was obtained. Examples

[0025] Under N 2 ​Under protected conditions, 2 mmol of 8-hydroxy-9-guanidine aldehyde and 1 mmol of m-phenylenediamine were successively placed in a round-bottom flask, dissolved in 20 mL of absolute ethanol, and heated to reflux for 3 hours. After the reaction mixture was filtered, washed with absolute ethanol, and dried, a dark red compound C, 211.6 mg, was obtained with a yield of 42%.

[0026] The compounds A, B, and C obtained in Examples 1-3 were analyzed and determined, and the mass spectra of the three were Figure 1 identical. The MS (MALDI-TOF) data are as follows: an isotopic cluster peaking at m / z 504.64, [Calcd. For M + 504.19]; Anal. Calcd for C 24 H 24 N 2 O: C, 80.92; H, 7.19; N, 6.34. Found: C,80.75; H, 7.23; N, 6.52, which is basically consistent with the theoretical value of the guanidine-m-phenylenediamine compound. Thus, the molecular structures of compounds A, B, and C can be confirmed as:

[0027] , that is, the guanidine-m-phenylenediamine molecule. Example

[0028] Aggregation properties of the guanidine-m-phenylenediamine compound in a THF-H 2 O mixed solvent: Using the guanidine-m-phenylenediamine compound with a concentration of 2×10 -5 mol / L as the research object, THF-H 2 O mixed solvents containing different proportions of water were added respectively. The study of its ultraviolet absorption spectral properties showed that the guanidine-m-phenylenediamine compound had a maximum absorption peak at 406 nm in pure THF solvent. As the water content in the mixed solvent increased continuously from 0% to 60%, the maximum ultraviolet absorption of this compound gradually red-shifted to around 434 nm, but its absorbance basically did not change. When the proportion of water in the mixed solvent continued to increase to more than 65%, the absorbance of the maximum absorption peak of the guanidine-m-phenylenediamine compound decreased, the absorption peak slightly blue-shifted and broadened, and at the same time, a tail-up phenomenon appeared after 480 nm, indicating that the compound had aggregated. These studies show that the guanidine-m-phenylenediamine compound has an aggregation phenomenon in a THF-H 2 O mixed solvent with a relatively high water content. Example

[0029] Aggregation properties of the guanidine-m-phenylenediamine compound in THF-H2 Aggregation-induced emission performance in mixed solvents of O: At a concentration of 2×10 -5 mol / L of julolidine-m-phenylenediamine compound was used as the research object, and THF-H 2 The fluorescence emission optical properties of the mixed solvent of THF-H O showed that as the water content in the mixed solvent increased from 0% to 60%, the maximum fluorescence emission of the julolidine-m-phenylenediamine compound at 570 nm remained basically unchanged; then, as the water content increased from 60% to 98%, the maximum fluorescence emission intensity of the Schiff base compound gradually increased to 1.8 times, indicating that the julolidine-m-phenylenediamine compound was more stable in the presence of water in THF-H O. 2 O mixed solvents have aggregation-induced fluorescence enhancement properties.

[0030] Example 6

[0031] Julolidine-p-phenylenediamine compound in THF-H 2 Aggregation performance in mixed solvents: with a concentration of 2×10 -5 mol / L of julolidine-p-phenylenediamine compound was used as the research object, and THF-H containing different proportions of water was added. 2 The study of the ultraviolet absorption spectrum of the mixed solvent of Julolidine-p-phenylenediamine in pure THF solvent shows that: in pure THF solvent, the Julolidine-p-phenylenediamine compound has a maximum absorption peak at 441 nm; as the water content in the mixed solvent increases from 0% to 65%, the maximum ultraviolet absorption of the compound gradually red-shifts to around 463 nm, and its absorbance decreases slightly; continuing to increase the proportion of water in the mixed solvent to more than 70%, the absorbance of the Julolidine-p-phenylenediamine compound decreases, the absorption peak slightly blue-shifts and becomes wider, and the tail end tilts after 520 nm, indicating that the compound has aggregated. These studies show that the Julolidine-p-phenylenediamine compound in THF-H with a water content of more than 70% 2 O has aggregation phenomenon in mixed solvents.

[0032] Example 7

[0033] Julolidine-p-phenylenediamine compound in THF-H 2 Aggregation-induced emission performance in mixed solvents of O: At a concentration of 2×10 -5 mol / L of julolidine-p-phenylenediamine compound was used as the research object, and THF-H 2O mixed solvents. The study on their fluorescence emission optical properties shows that: as the water content in the mixed solvents increases from 0% to 65%, the maximum fluorescence emission of the julolidine-p-phenylenediamine compound at 530 nm gradually increases; then as the water content increases from 70% to 98%, the julolidine-p-phenylenediamine compound aggregates, but its maximum fluorescence emission intensity gradually decreases. These studies indicate that the julolidine-p-phenylenediamine compound has the phenomenon of aggregation-induced fluorescence quenching in THF-H 2 O mixed solvents with a relatively high water content.

[0034] Example 8

[0035] Fluorescence selective detection performance of the julolidine-m-phenylenediamine compound for Al 3+ : In a 90% aqueous DMF solution of the julolidine-m-phenylenediamine Schiff base compound with a concentration of 2×10 -5 mol / L, 10-fold molar amounts of different metal ions were added respectively. From the changes in its fluorescence emission spectrum, it can be seen that: the free julolidine-m-phenylenediamine compound has a maximum fluorescence emission peak at 575 nm and a slightly weaker fluorescence emission shoulder peak near 480 nm; after the addition of Ag + , K + , Na + , Ba 2+ , Ca 2+ , Mg 2+ , Cd 2+ , Hg 2+ , Mn 2+ , Ni 2+ , Zn 2+ , Co 2+ , Cu 2+ , Fe 3+ and other metal ions, the change in the fluorescence emission spectrum of this fluorescent compound is small; after the addition of Al 3+ , the fluorescence emission of this compound at 480 nm is significantly enhanced, indicating that the julolidine-m-phenylenediamine compound has the potential for fluorescence "off-on" detection of Al 3+ ions.

Claims

1. A julolidine aggregation-induced emission material, whose molecular structure is as follows:

2. A preparation method of the julolidine aggregation-induced emission material according to claim 1, characterized in that the following steps: Under N 2 Under protective conditions, α mmol of -8-hydroxy-9-julolidine aldehyde and β mmol of m-phenylenediamine are successively placed in a round-bottom flask, dissolved in γ mL of absolute ethanol, and then δ μL of glacial acetic acid is added to the above solution. The temperature is raised to reflux for 3-6 hours. After filtering the reaction mixture, washing with absolute ethanol, and drying, an orange-red julolidine-m-phenylenediamine compound is obtained; α:β:γ:δ is 2:1:20:

200.

3. An application of the julolidine aggregation-induced emission material according to claim 1, characterized in that Containing both an imine and an ortho-phenolic hydroxyl group as two ion-acting sites, and showing a sensitive "turn-off - turn-on" fluorescence detection signal after complexing with Al 3+ ​

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