CN112209849A

CN112209849A - Synthesis and application of fluorescent sensor capable of singly and selectively identifying methylbenzene

Info

Publication number: CN112209849A
Application number: CN202011179124.2A
Authority: CN
Inventors: 林奇; 黄婷婷; 哈力; 魏太保; 张有明; 姚虹
Original assignee: Northwest Normal University
Current assignee: Northwest Normal University
Priority date: 2020-10-29
Filing date: 2020-10-29
Publication date: 2021-01-12
Anticipated expiration: 2040-10-29
Also published as: CN112209849B

Abstract

The invention designs and synthesizes a fluorescence sensor capable of identifying methylbenzene with single selectivity, and 4,4 '-biphenol and hexamethylenetetramine are taken as substrates and reacted in a trifluoroacetic acid solvent to prepare 4, 4' -biphenol derivative FA; and then hydrazine hydrate and 4, 4' -biphenol derivative are used as substrates, and the target fluorescence sensor FB is obtained through reaction in absolute ethyl alcohol. H at fluorescence sensor F₂Adding methanol, ethanol, DMSO, DMF, acetonitrile, acetone, dichloromethane, tetrahydrofuran, ethyl acetate, toluene and cyclohexane into O solution respectively, and finding that the fluorescence of the fluorescence sensor FB can be turned on only by adding toluene, so that the single selectivity of the fluorescence sensor FB on toluene molecules is realizedAnd (5) identifying.

Description

Synthesis and application of fluorescent sensor capable of singly and selectively identifying methylbenzene

Technical Field

The invention relates to a synthesis method of a fluorescent sensor capable of identifying toluene with high sensitivity and single selectivityA method; the invention also relates to the fluorescent sensor at H₂An application of fluorescence recognition toluene in O solution belongs to the fields of chemical synthesis and molecular detection.

Background

Toluene, a colorless, volatile liquid with special aroma. Has strong refractivity. Can be mixed with ethanol, diethyl ether, acetone, chloroform, carbon disulfide and glacial acetic acid, and is very slightly soluble in water. Toluene is flammable, its vapor can form explosive mixtures with air, and high concentrations of gas are anesthetic and irritating. It is an industrial raw material, mainly used for making fuel, oil and so on. Toluene is harmful to human, and long-term exposure to toluene can easily cause diseases of the blood system, such as leukemia and lymphoma, which are caused by toluene. Toluene also causes respiratory irritation such as cough, runny nose, chest tightness, etc.

At present, a toluene detector is mainly used for detecting toluene, is an industrial high-sensitivity wide-range combustible gas leakage detector, can detect dozens of combustible gases, can detect the concentration of the combustible gas in the environment, and can vibrate and give an audible and visual alarm when the toluene detector detects that the content of the combustible gas in the air is equal to or greater than an alarm value. However, the toluene detector is inconvenient to operate, has long standby time and is not high in sensitivity.

Disclosure of Invention

The invention aims to provide a fluorescent sensor capable of singly and selectively identifying toluene;

another object of the present invention is to provide a method for synthesizing the above fluorescence sensor;

it is also an object of the present invention to provide a specific application of the fluorescence sensor.

Fluorescent sensor and synthesis thereof

The preparation method of the fluorescence sensor comprises the following steps:

(1) preparation of 4, 4' -biphenol derivative FA: reacting 4, 4' -biphenol and hexamethylenetetramine serving as substrates at 135-140 ℃ for 70-72 h by using trifluoroacetic acid as a solvent; after the reaction is finished, adding dilute hydrochloric acid, stirring and filtering, wherein the product is an orange solid, and recrystallizing the orange solid by using dimethyl sulfoxide to obtain a 4, 4' -biphenol derivative; wherein the molar ratio of the substrate 4, 4' -biphenol to hexamethylenetetramine is 1: 8-1: 10.

(2) Synthesis of fluorescence sensor FB: hydrazine hydrate and 4, 4' -biphenol derivatives are used as substrates, absolute ethyl alcohol is used as a solvent, the reaction is carried out for 20-24 hours at the temperature of 75-80 ℃, orange solids are separated out after the reaction is finished, the suction filtration is carried out, hot ethyl alcohol is used for leaching, and the obtained product is the fluorescence sensor FB. Wherein the molar ratio of the substrate hydrazine hydrate to the 4, 4' -biphenol derivative is 1: 2-1: 4.

The molecular formula of the prepared fluorescence sensor is as follows: c₁₆H₁₈N₈O₂The notation is: FB, the synthetic route is as follows:

the mass spectrum and hydrogen spectrum of intermediate FA are shown in fig. 1 and 2. The mass spectrum and hydrogen spectrum of the sensor molecule FB are shown in fig. 3 and 4.

Application of fluorescent sensor in detecting toluene

1. Fluorescence properties of the fluorescence sensor FB

The research on the fluorescence property of the sensor FB shows that the fluorescence sensor FB is at H₂The O solution has good solubility. When the excitation wavelength is 345nm, the sensor molecule FB has no fluorescence emission performance, and the fluorescence intensity is almost zero.

2. FB fluorescent recognition toluene of fluorescent sensor

H at the fluorescence sensor FB₂O solution (C)_FB=2×10^-6M), adding methanol, ethanol, DMSO, DMF, acetonitrile, acetone, dichloromethane, tetrahydrofuran, ethyl acetate, toluene and cyclohexane of which the volume is 1 percent of that of the FB aqueous solution respectively. The solution was observed for changes in fluorescence. FIG. 5 shows a sensor according to the present inventionH of molecular FB₂Adding fluorescence spectrograms (lambda) of different solvents into the O solution respectively_ex=345 nm). As a result, it was found that only the addition of toluene allowed the H of the fluorescence sensor FB to be obtained₂The O solution fluoresces on. While the addition of other solvents can not make the H of the fluorescence sensor FB₂The fluorescence of the O solution is turned on, which indicates that the fluorescence sensor FB has single selection identification performance on the toluene.

The fluorescence titration experiment shows that the lowest detection limit of the fluorescence sensor FB on the toluene is 8.19 multiplied by 10^-6M (as shown in fig. 6 and 7).

3. Analysis of recognition mechanisms

The mechanism of toluene recognition by a fluorescence sensor FB is researched through a nuclear magnetic hydrogen spectrum diagram. DMSO + injection into FB hostd ₆After adding toluene in a volume ratio of 0.1%, 0.5%, 1% to the solution, respectively, the change of nuclear magnetic hydrogen spectrum peak was observed. FIG. 8 shows DMSO-of the sensor molecule FB-of the present inventiond ₆Nuclear magnetic hydrogen spectra of various volumes of toluene added to the solution. As can be seen from FIG. 8, with the addition of toluene, the-NH peak on hydrazine hydrate disappeared, which indicates that the fluorescence sensor FB is deprotonated. And the hydroxyl peak on the 4, 4' -biphenol derivative generates low-field displacement, which indicates that hydrogen bonding action is generated between the hydroxyl and the toluene, so that the fluorescence of the fluorescence sensor FB is combined with the toluene to form a complex, and the fluorescence of the fluorescence sensor FB is turned on after the toluene is added.

Drawings

FIG. 1 is a mass spectrum of intermediate FA of the present invention;

FIG. 2 is a hydrogen spectrum of intermediate FA according to the present invention;

FIG. 3 is a mass spectrum of sensor molecule FB of the present invention;

FIG. 4 is a hydrogen spectrum of sensor molecule FB of the present invention;

FIG. 5 shows H of a sensor molecule FB according to the invention₂Adding different solvents into O solution respectively to obtain full-scan curve (lambda)_ex=345 nm)；

FIG. 6 shows H of a sensor molecule FB according to the invention₂Fluorescence titration of toluene in O solution (. lamda.)_ex=345 nm)；

FIG. 7 is a drawing showingH of the sensor molecule FB of the invention₂The lowest detection limit of toluene added into the O solution;

FIG. 8 shows H of a sensor molecule FB according to the invention₂Nuclear magnetic hydrogen spectrograms of different volumes of toluene added to the O solution.

Detailed Description

The preparation of the sensor molecule FB and the use of the fluorescent recognition of toluene according to the invention are further illustrated by the following specific examples.

Example 1 fluorescence sensor FB

(1) Preparation of 4, 4' -biphenol derivative FA: 0.9g (50 mmol) of 4, 4' -biphenol and 17g of hexamethylenetetramine (500 mmol) are weighed, added to 10mL of trifluoroacetic acid, and reacted at 140 ℃ for 72 h; after the reaction is finished, adding dilute hydrochloric acid, stirring and filtering, wherein the product is an orange solid, and recrystallizing with dimethyl sulfoxide to obtain 7.45g of FA with the yield of 52%;

(2) synthesis of fluorescence sensor FB: 1.5mL (4 mmol) of hydrazine hydrate and 0.29g (1 mmol) of FA are weighed and added into 20mL of absolute ethyl alcohol, the mixture reacts for 24 hours at the temperature of 80 ℃, orange solid is separated out after the reaction is finished, the filtration is carried out, the hot ethanol is used for leaching, the obtained product is the fluorescence sensor FB, and the yield is 75%.

Example 2 identification of toluene by fluorescent sensor FB

Remove H of 2 mL fluorescence sensor FB₂O solution (C)_FB=2×10^-6M) adding methanol, ethanol, DMSO, DMF, acetonitrile, acetone, dichloromethane, tetrahydrofuran, ethyl acetate, toluene and cyclohexane with the volume of 1% of that of the FB aqueous solution into a series of colorimetric tubes respectively, and adding H of sensor molecules₂The O solution fluorescence is turned on, which indicates that toluene is added; if the fluorescence of the sensor molecule is not turned on, it is indicated that toluene is not added.

Claims

1. A fluorescence sensor capable of single selective recognition of toluene with molecular formula of C₁₆H₁₈N₈O₂The structural formula is as follows:

。

2. the method for synthesizing a fluorescence sensor capable of single selective recognition of toluene according to claim 1, comprising the steps of:

(1) synthesis of 4, 4' -biphenol derivative FA: reacting 4, 4' -biphenol and hexamethylenetetramine serving as substrates at 135-140 ℃ for 70-72 h by using trifluoroacetic acid as a solvent; after the reaction is finished, adding dilute hydrochloric acid, stirring and filtering, wherein the product is orange solid powder, and recrystallizing with dimethyl sulfoxide to obtain 4, 4' -biphenol derivative FA;

(2) synthesis of fluorescence sensor FB: hydrazine hydrate and FA are used as substrates, absolute ethyl alcohol is used as a solvent, the reaction is carried out for 20-24 hours at 75-80 ℃, orange solid is separated out after the reaction is finished, the suction filtration is carried out, hot ethyl alcohol is used for leaching, and the obtained product is the fluorescence sensor FB.

3. The method for synthesizing a fluorescence sensor capable of single selective recognition of toluene according to claim 2, wherein: in the step (1), the molar ratio of the substrate 4, 4' -biphenol to hexamethylenetetramine is 1: 8-1: 10.

4. The method for synthesizing a fluorescence sensor capable of single selective recognition of toluene according to claim 2, wherein: in the step (1), the molar ratio of the substrate 4, 4' -biphenol derivative to hydrazine hydrate is 1: 2-1: 4.

5. The use of the fluorescence sensor according to claim 1 for the single selective recognition of toluene for the recognition of toluene: the method is characterized in that: in fluorescent sensors H₂Adding methanol, ethanol, DMSO, DMF, acetonitrile, acetone, dichloromethane, tetrahydrofuran, ethyl acetate, toluene and cyclohexane into O solution respectively, wherein only the addition of the toluene can enable H of the fluorescence sensor₂The O solution fluoresces on.