CN102786459A - Squarylium type chemical sensor for colorimetric identification of copper ion and preparation method thereof - Google Patents

Abstract

The invention discloses a squarylium-based chemical sensor for colorimetric recognition of copper ions and a preparation method thereof, belonging to the field of chemical analysis and testing. Its 2,3,3-trimethylindole squarylium compound with symmetrical structure is carried out according to the following steps: 2,3,3-trimethylindole ring compound and squarylium are mixed in a molar ratio of 2:1 Mix and add to a three-necked flask, add a mixed solvent of toluene and n-butanol with a volume ratio of 1:1, heat, stir and reflux for 2-24 hours, and separate the water generated during the reaction with a water separator; stop heating, cool to room temperature, and depressurize Part of the solvent was removed by evaporation, and a green solid was obtained after filtration; the obtained green solid was washed repeatedly with ethyl acetate, then dried at 60°C, and recrystallized with ethanol solvent to obtain pure green crystals. In the process of recognizing copper ions, the squarylium compound of the present invention not only has a change in absorption spectrum, but also changes in color, has obvious characteristics, and is beneficial to detect copper ions.

Description

A squaraine-based chemical sensor for colorimetric recognition of copper ions and its preparation method

technical field

The invention specifically relates to a squarylium-based chemical sensor for colorimetric recognition of copper ions and a preparation method thereof, belonging to the technical field of chemical analysis and testing.

Background technique

In recent years, the detection and identification of metal ions, especially transition metal ions, in living organisms and the environment has attracted widespread attention. And copper ion, as an important element in the process of human life activities, its directional detection and identification in aqueous solution has received great attention. Copper is one of the indispensable trace elements to maintain the normal life activities of organisms. Although its content is small, it plays a very important role. When the concentration of copper ions in the body exceeds or falls below the concentration range required by the cells, it will disturb the normal activities of the life system and poison the cells, thus causing serious copper metabolism disorders, such as hepatolenticular degeneration, Alzheimer's Alzheimer's disease, Menkes syndrome, etc. Trace amounts of copper ion pollution in the environment can be enriched through the action of the biological chain. When people drink or eat water and food contaminated with copper ions, resulting in excessive copper ion content in the body, it will cause various incurable diseases. Therefore, it is necessary to detect copper ions in the natural environment and in vivo.

The design and synthesis of chemical sensors with selective recognition function for copper ions has attracted much attention in recent years, and has become a research hotspot in the fields of chemical science, environmental science and life science. Chinese patent CN101446547A has invented a copper ion fluorescent probe, which is to make polyethyleneimine into polyethyleneimine aqueous solution, then react in a polytetrafluoroethylene-lined reactor, and obtain a yellow viscous liquid after evaporating the solvent , The reaction needs to add ammonium persulfate, hydrogen peroxide, peracetic acid, iodic acid and other substances as oxidants, the reaction conditions are complex, the reaction temperature is high, and the obtained viscous liquid is not easy to store and carry. The preparation of the copper ion fluorescent probe invented by Chinese patent CN101261228A is relatively complicated, and only the fluorescence is enhanced, and there is no color change, and the discrimination and identification are not obvious, which is not conducive to practical application.

Squaraine is a 1,3-disubstituted derivative formed by the condensation of squaraine with electron-rich aryl compounds or amine compounds. The salient features of this type of compound are narrow and strong absorption bands and high quantum yields in the visible to infrared region. This photoelectric property is mainly derived from the strong donor-acceptor-donor (donor- charge transfer between acceptor-donor). In recent years, squaraine compounds have been favored for their excellent optical properties and good light stability, and have become one of the hot spots in the research of functional dyes. In addition, squaraine compounds are sensitive to media, and their optical properties vary greatly in different solvents, and their own color can change significantly after interacting with certain compounds, so they are ideal materials for building chemical sensors.

A squarylium-based chemical sensor for colorimetric recognition of copper ions involved in the present invention has a simple synthesis method, easy control of reaction conditions, and a pure product can be obtained through simple treatment. In addition, as a chemical sensor for copper ion recognition, it is convenient Acid cyanine has the advantages of high sensitivity and good selectivity.

Contents of the invention

The object of the present invention is to provide a squarylium-type copper ion colorimetric recognition chemical sensor with good selectivity, and to provide a preparation method of this type of chemical sensor with simple synthesis method and low production cost.

For realizing the object of the present invention, technical scheme is as follows:

A squarylium chemical sensor for colorimetric identification of copper ions, which has a symmetrical structure of 2,3,3-trimethylindole squarylium compound, and its structural formula is shown in the following formula:

In the formula, R is one of H or -CH ₂ CH ₂ OH.

The squarylium compounds synthesized in the present invention mainly contain following two kinds:

Compound [1]

Compound [2]

The preparation method of the above-mentioned squarylium chemical sensor for colorimetric recognition of copper ions, the chemical reaction formula is as follows:

The preparation method of the above-mentioned squarylium chemical sensor for colorimetric recognition of copper ions is carried out according to the following steps:

(1) Condensation reaction: Mix 2,3,3-trimethylindole ring compound and squarylium in a molar ratio of 2:1 into a three-necked flask, add a mixed solvent of toluene and n-butanol at a volume ratio of 1:1, Heat, stir and reflux for 2-24 hours, and the water generated in the reaction is separated with a water separator;

(2) Stop heating, cool to room temperature, remove part of the solvent by evaporation under reduced pressure, and obtain a green solid after filtration;

(3) The obtained green solid was repeatedly washed with ethyl acetate, then dried at 60°C, and recrystallized with ethanol solvent to obtain pure green crystals.

The chemical sensor for colorimetric recognition of squaraine-type copper ions described in the invention can be widely used to detect the copper ion content in plants, human cells and environmental sewage.

The advantages and effects of the squarylium chemical sensor for colorimetric recognition of copper ions obtained by the present invention are as follows:

(1) The synthesis method of the squaraine compound of the present invention is simple, the reaction conditions are easy to control, and a pure product can be obtained through simple treatment, and the obtained squaraine compound has excellent optical properties and light stability;

(2) In the process of recognizing copper ions, the squaraine compound of the present invention not only has a change in the absorption spectrum, but also changes in color, with obvious characteristics, which is beneficial to the detection of copper ions.

(3) The squaraine compound of the present invention is a solid powder, which is convenient to use and store, has low synthesis cost, and has a good promotion prospect.

Description of drawings

Fig. 1 is the absorption spectrogram after the squaraine compound [1] prepared in Example 1 reacts with copper ions of different concentrations.

Fig. 2 is the absorption spectrogram after the squaraine compound [2] prepared in Example 2 interacts with copper ions at different concentrations.

Detailed ways

In order to better understand the present invention, the content of the present invention will be further clarified below in conjunction with the examples and application examples, but the content of the present invention is not limited to the following examples and application examples.

Example 1

Preparation of squaraine compound [1]

Weigh 2.8565g about (0.018mol) of 2,3,3-trimethyl-3H indole and 1.0240g (about 0.009mol) of squaraine, add them to a 250ml three-necked flask respectively, measure 20.0mL of toluene and 20.0mL of n- Butanol was added therein, heated and stirred to reflux for 2 hours, and the water generated by the reaction was removed by a water separator, the heating was stopped and cooled to room temperature, part of the solvent was removed by distillation under reduced pressure, and a green solid was obtained after filtration. The obtained solid was repeatedly washed with ethyl acetate, then dried at 60°C, and recrystallized with ethanol solvent to obtain a green crystal which was the squaraine compound [1].

Example 2

Preparation of squaraine compound [2]

(1) Preparation of intermediate N-hydroxyethyl-2,3,3-trimethylindole

Add 1.5481g (0.0097mol) of 2,3,3-trimethyl-3H-indole, 1.3376g (0.011mol) of 2-bromoethanol, and 25.0mL of absolute ethanol into a 250ml one-necked flask, heat to 78°C, and After refluxing for 23 hours under this condition, stop heating and cool to room temperature, a small amount of red solid precipitates at the bottom of the bottle. After vacuum distillation to remove the solvent, a pink solid is obtained, which is washed repeatedly with ethyl acetate, and then dried at 60°C. A pink solid was obtained.

(2) Preparation of N-hydroxyethyl-2,3,3-trimethylindole squaraine compound [2]

Weigh 1.093g (0.0040mol) of N-hydroxyethyl-2,3,3-trimethylindole and 0.2607g (0.0020mol) of squaraine, add them to a 250ml three-necked flask respectively, measure 20.0mL of toluene and 20.0 Add 1 mL of n-butanol, heat, stir and reflux for 24 hours, remove the water generated by the reaction at the same time, stop heating and cool to room temperature, remove part of the solvent by distillation under reduced pressure, and obtain a green solid after filtration. The obtained solid was repeatedly washed with ethyl acetate, then dried at 60°C, and recrystallized with ethanol solvent to obtain a dark green solid which was the squaraine compound [2].

Application example 1

[ 1] Prepare a solution with a concentration of 2×10 ^-5 mol/L. Take 50ml of the prepared solution, add dropwise to the solution a copper ion solution with a concentration of 1×10 ^-2 mol/L, and measure the changes in its absorption spectrum sequentially with a UV-visible spectrophotometer. The squarylium compound prepared in Example 1 [1] The absorption spectrum after interacting with different concentrations of copper ions is shown in Figure 1. It can be seen from the figure that as the concentration of copper ions increases, the absorption spectrum of squaraine compound [1] changes, and the absorption peak at 648nm gradually decreases, while the absorption band between 400-450nm gradually increases. In addition, the color of the solution also changed from blue to light green.

Application example 2

The squaraine compound [2] synthesized in Example 2 was prepared into a solution with a concentration of 1×10 ^-5 mol/L by using the mixed solution of absolute ethanol-water (80:20 by volume) as the solvent. Take 50ml of the prepared solution, add dropwise to the solution a copper ion solution with a concentration of 5×10 ^-4 mol/L, and use a UV-Vis spectrophotometer to sequentially measure the changes in its absorption spectrum. The squarylium compound prepared in Example 2 [2] The absorption spectrum after interacting with different concentrations of copper ions is shown in Figure 2. It can be seen from the figure that with the increase of copper ion concentration, the absorption spectrum of squaraine compound [2] changes, the absorption peak at 632nm gradually decreases, while the absorption peak at 436nm gradually increases. In addition, the color of the solution also changed from blue to blue-green.

Claims (2)

1. one kind is used for the sour cyanines class chemical sensor than the side of colour discrimination cupric ion, it is characterized in that shown in its structural formula following formula:

；

In the formula, R be H or-CH ₂CH ₂A kind of among the OH.

2. the described a kind of preparation method who is used for than the side of colour discrimination cupric ion sour cyanines class chemical sensor of claim 1 is characterized in that carrying out according to following steps:

(1) condensation reaction: with 2; 3,3-tri-methyl indole cyclic cpds mixes according to mol ratio 2:1 with side's acid and adds there-necked flask, and adding volume ratio is toluene and the n-butanol mixed solvent of 1:1; Heated and stirred backflow 2-24 hour, the water that generates in the reaction is told with water trap;

(2) stop heating, be cooled to room temperature, the evaporation under reduced pressure removed partial solvent obtains green solid after the filtration;

(3) green solid that obtains with the ETHYLE ACETATE repetitive scrubbing, 60 ℃ of oven dry are down carried out recrystallization with alcohol solvent then, obtain purified green crystal.

Images