CN104892533B - Tb (III) coordination compound and preparation method thereof and the application in detection cynocks - Google Patents

Abstract

The invention discloses a kind of Tb (III) coordination compound and preparation method thereof and the application in detection cynocks.The structural formula of the coordination compound is that, with Isosorbide-5-Nitrae, 7 7-triazacyclononane derivants are part for which, and with Tb (III) cooperations, preparation method is extremely simple, and reaction condition is gentle.The features such as Tb (III) coordination compound of the present invention has fluorescence lifetime length, Stokes shift big and is coordinated unsaturated, can effectively be coordinated with neutral molecule cynocks, and Tb (III)⁵D₄The T of energy level and cynocks₁Energy level matched, it is ensured that effective energy transfer can occur therebetween and the fluorescence of Tb (III) coordination compound is significantly sensitized.Therefore, the coordination compound has stronger selectivity to cynocks, can realize the high selectivity to cynocks, high sensitivity sensing identification, and operating process is simple and convenient, and the efficient detection for cynocks provides a kind of new method of convenient, rapid low consumption.

Description

Tb(III) complexes and their preparation methods and their application in detection of fenitronil

technical field

The invention belongs to the technical field of small-molecule fluorescent sensing, and in particular relates to a Tb(III) complex fluorescent sensor with high selectivity and high sensitivity for detecting the organophosphorus pesticide fenitronil.

Background technique

Pesticide is a general term for a class of drugs used to prevent, eliminate or control diseases, insects, grasses and other harmful organisms that endanger agriculture and forestry, and to regulate the growth of plants and insects purposefully. However, the excessive use and abuse of pesticides has brought great harm to the ecological environment and human health. In recent years, pesticide pollution and pesticide poisoning incidents have occurred from time to time. It can be seen that the development of efficient, fast and convenient methods for pesticide detection is very important to eliminate such incidents. . At present, the means used to detect organophosphorus pesticide residues at home and abroad mainly include gas chromatography technology, high performance liquid chromatography technology, immunoassay technology, enzyme inhibition technology, biosensor technology and fluorescence method. Among them, the gas chromatograph is cumbersome, expensive, and requires relatively high operating requirements and strong professionalism. It also requires pretreatment of samples, and the operation is cumbersome and complicated, which is not conducive to the flexible application and rapid mastery of pesticide detection. High-performance liquid chromatography requires a long time for analysis, and the sample also needs to be pretreated. The complicated process is not conducive to rapid detection. Immunoassay has difficulties such as complex preparation of immunogen, difficulty in obtaining immunogen, specificity of immune response, strong antibody selectivity, and large initial investment, which is not suitable for my country's national conditions. The cholinesterase used in the enzyme inhibition technology cannot be preserved at room temperature, and the source of the enzyme is unstable. The detection results of different batches of the enzyme are different, and the detection results are affected. The selectivity of biosensing technology is not high, the enzyme used is unstable, and there is a phenomenon of enzyme inactivation. Fluorescence method has significant advantages such as high sensitivity, good selectivity, rich fluorescence output signal, simple operation, etc. It is expected to provide a new strategy for the efficient detection of organophosphorus pesticides.

Fenitronil is a broad-spectrum organophosphorus insecticide, especially for rice borers, rice bract insects, rice planthoppers, rice leaf rollers, leafhoppers, armyworms and other control effects are more significant. However, fenitronil can form phosphorylated acetylcholinesterase with acetylcholinesterase in the human body, which will inhibit the activity of acetylcholinesterase and lose the ability to decompose acetylcholine, resulting in the accumulation of acetylcholine in the nervous system, resulting in corresponding nervous system dysfunction. Therefore, it is of great significance for the highly selective and sensitive detection of fenitronil.

Contents of the invention

The technical problem to be solved by the present invention is to overcome the problems of cumbersome operations such as sample pretreatment in the process of traditional detection of fenonitrile and the high cost and poor reproducibility of biological detection methods, and provide a method that can achieve high detection of fenonitrile. Selective, highly sensitive detection and easy to operate, low-cost fluorescent chemical sensor - Tb (III) complexes.

The technical solution adopted to solve the above problems is that the structural formula of this Tb(III) complex is as follows:

The preparation method of above-mentioned Tb (III) complex is made up of following steps:

1. Synthetic ligand

Using ethanol as a solvent, mix 1,4,7-triazacyclononane, triethylamine, and bromoacetamide in a molar ratio of 1:3 to 4:3 to 4, reflux and stir the reaction, separate and purify the product, and obtain the formula Ligands shown in I.

2. Synthesis of Tb(III) complexes

Dissolve the ligand shown in formula I completely in distilled water, add terbium chloride hexahydrate under stirring at room temperature, continue to stir for 24 hours, separate and purify the product, and obtain Tb(III) complex, wherein the ligand and chloride hexahydrate The molar ratio of terbium is 1:1-1.5.

The purposes of the Tb(III) complex of the present invention in detecting fenonitrile, concrete method is as follows:

Add the Tb(III) complex into methanol to prepare a 50-60 μmol/L Tb(III) complex solution, then add different volumes of ceranitronil standard samples to it, and use a fluorescence spectrometer to measure the response Fluorescence intensity of the system and draw the standard curve that I/I _O value changes with the concentration of cenonitrile; Measure the fluorescence intensity of the sample to be measured with a fluorescence spectrometer according to the above method, according to the I/I _O value of the sample to be measured, combined with the standard curve of the standard curve A linear equation can be used to identify cenonitrile with high selectivity and determine the concentration of cnitronil in the sample to be tested.

Compared with prior art, the beneficial effect that the present invention has is as follows:

The preparation method of the Tb(III) complex of the present invention is extremely simple, and the reaction conditions are mild. The prepared Tb(III) complex has the characteristics of long fluorescence lifetime, large Stokes shift and coordination unsaturation, and can be combined with neutral molecules. The ⁵ D ₄ energy level of Tb(III) is highly matched with the T ₁ energy level of cenonitronitrile, which ensures effective energy transfer between the two and greatly sensitizes the Tb(III) complex of fluorescence. Therefore, the complex has strong selectivity to cenonitrile, and can realize high selectivity and high sensitivity sensing and identification of cenonitrile, and the operation process is simple and convenient, avoiding the cumbersome sample pretreatment in traditional methods. Due to the high cost and poor reproducibility of the operation and biological detection methods, it provides a convenient, fast and low-cost new method for the efficient detection of fenitronil.

Description of drawings

Fig. 1 is the fluorescence spectrogram of the fluorescence intensity of the Tb(III) complex changing with the concentration of cenonitrile.

Fig. 2 is a linear graph showing the relative fluorescence intensity of Tb(III) complexes changing with the concentration of cenonitrile.

Fig. 3 is a comparison chart of fluorescence intensity of Tb(III) complexes in different organophosphorus pesticides.

detailed description

The present invention will be described in further detail below in conjunction with the accompanying drawings and embodiments, but the protection scope of the present invention is not limited to these embodiments.

Example 1

1. Synthetic ligand

Dissolve 0.75g (5.6mmol) of 1,4,7-triazacyclononane completely in 50mL of ethanol, then add 2.8mL (20.2mmol) of triethylamine and 2.71g (19.6mmol) of bromoacetamide, and heat to reflux After stirring for 6 hours, naturally cool to room temperature, filter with suction, and vacuum-dry the obtained white solid at 35° C. to obtain the ligand shown in Formula I. The reaction equation is as follows:

The structural characterization data of the obtained ligand are: ¹ H-NMR, δ _H (600MHz, D ₂ O, Me ₄ Si): 3.65 (6H, CH ₂ CONH ₂ ), 2.96 (12H, N CH ₂ CH ₂ N). IR: (KBr, v _Max /cm ^-1 ): 3507 (NH), 1667 (C=O). ¹ C-NMR, δ _C (600 MHz, D ₂ O, Me ₄ Si): 173.66 (3C, C=O), 56.91 (3C, CH ₂ ), 49.37 (12C, N CH ₂ CH ₂ N). MS (ESI, m/z): Calc: 301.1988 ([M+H] ⁺ ), found: 301.1992.

2. Synthesis of Tb(III) complexes

150.2mg (0.5mmol) of the ligand shown by formula I was completely dissolved in 40mL of distilled water, and slowly added dropwise with 186.7mg (0.5mmol) of terbium chloride hexahydrate solution completely dissolved in 30mL of distilled water under stirring at room temperature, and stirred at room temperature for 24 After 1 hour, the solvent was evaporated under reduced pressure, the resulting solid matter was dissolved in 3mL of methanol, and added dropwise to a flask containing 100mL of ether, a white precipitate was precipitated, stirred at room temperature for 1 hour and then suction filtered. After the filter cake was dissolved in methanol, press the above Methods Recrystallize three times with 100 mL of diethyl ether, then recrystallize twice with dichloromethane, and dry the obtained solid under vacuum at 35°C to obtain a Tb(III) complex. The reaction equation is as follows:

The structural characterization data of the obtained Tb(III) complex is: IR (KBr, v _Max /cm ^-1 ): 3370, 3117 (NH), 1661, 1593 (C=O). MS (ESI, m/z): Theoretical: 529.0541 ([M-Cl] ⁺ ), 247.0426 ([M-2Cl] ²⁺ ), Found: 529.0546, 247.0396.

Example 2

The purposes of Tb (III) complex in detecting fenitronil, concrete method is as follows:

Prepare the methanol solution of 50 μmol/L Tb (III) complex, add cenonitrile in this solution, make the concentration of cenonitrile in the gained mixed solution be respectively 0,10,20,30,40,50,60,70 . 2nm, emission slit is 3nm), the fluorescence spectrogram that fluorescence intensity changes with the concentration of cenonitrile is shown in Fig. 1, and draws the linear graph of I/I ₀ value with the change of concentration of cenonitrile, the results are shown in Fig. 2.

It can be seen from Figure 1 that the fluorescence intensity of the Tb(III) complex changes significantly with the increase of the concentration of cenonitrile in the system, and can be sensitized by about 55 times, indicating that the detection sensitivity of the Tb(III) complex to cenonitrile Very high; when the concentration of fenitronil is greater than 100 μmol/L, the fluorescence intensity will no longer increase. As can be seen from Figure 2, when the concentration of fenitronil is 0 to 100 μmol/L, the I/ _I0 value is linearly related to the concentration of fenitronil, and the linear equation is:

y=1.78033+0.53408x

In the formula, y is the I/I ₀ value, x is the concentration of fenitronil, and the correlation coefficient r is 0.99768. It can be seen from the correlation coefficient that the linear relationship between the I/I ₀ value and the concentration of fenitronil is very good.

In order to prove the beneficial effects of the present invention, the inventors added concentration of 100 μmol/L cenonitrile (2), profenofos (3), chlorpyrifos (4), chlorpyrifos to the methanol solution of 50 μmol/L Tb(III) complex respectively. Fruit (5), diazinon (6), phoxim (7), fenthion (8), methyl parathion (9), dichlorvos (10) methanol solution, and with 275nm as the excitation wavelength, The fluorescence intensity at the maximum emission wavelength of 547nm was recorded, and the methanol solution of the Tb(III) complex without any organophosphorus pesticide was used as a blank control (1). The results are shown in FIG. 3 .

It can be seen from Fig. 3 that among the nine organophosphorus pesticides, only fenitronil has a significant sensitization effect on the fluorescence of TbL(III) complexes, while other organophosphorus pesticides have no obvious effect on its fluorescence intensity, indicating that this Invented Tb(III) complexes have high selectivity to ceranitrile. It can be known by calculation that the detection limit of fenitronil can reach 59nmol/L.

Claims (4)

1. A Tb (III) complex is characterized in that the structural formula of the complex is as follows: 2. A preparation method of Tb (III) complexes as claimed in claim 1, characterized in that it is synthesized by the following steps: (1) Synthetic ligand Using ethanol as a solvent, mix 1,4,7-triazacyclononane, triethylamine, and bromoacetamide in a molar ratio of 1:3 to 4:3 to 4, reflux and stir the reaction, separate and purify the product, and obtain the formula The ligand shown in I; (2) Synthesis of Tb(III) complexes Dissolve the ligand shown in formula I completely in distilled water, add terbium chloride hexahydrate under stirring at room temperature, continue to stir for 24 hours, separate and purify the product, and obtain Tb(III) complex, wherein the ligand and chloride hexahydrate The molar ratio of terbium is 1:1-1.5. 3. the Tb (III) complex described in claim 1 is detecting the purposes in the fenonitrile. 4. The use of the Tb(III) complex according to claim 3 in the detection of cenonitrile, characterized in that: the Tb(III) complex is added to methanol to prepare 50-60 μmol/L of Tb(III) Complex solution, wherein the different volumes of the cnitronil standard sample is added, the fluorescent intensity of the corresponding system under the different concentrations is measured with a fluorescence spectrometer and draws the standard curve of the I/I _O value changing with the clonapyr concentration; according to the above-mentioned Methods The fluorescence intensity of the samples to be tested was measured with a fluorescence spectrometer. According to the I/I ₀ value of the samples to be tested, combined with the linear equation of the standard curve, the concentration of cenocarb in the samples could be identified with high selectivity.