阅读说明：本技术 一种用于水溶液中铜（ii）粒子检测的咪唑基希夫碱荧光传感器及其合成方法 (Imidazolyl Schiff base fluorescence sensor for detecting copper (II) particles in aqueous solution and synthetic method thereof ) 是由 侯士立 王俊杰 刘光艳 蓝珍妮 于 2021-08-27 设计创作，主要内容包括：本发明公开一种用于水溶液中铜(II)粒子检测的咪唑基希夫碱荧光传感器及其合成方法,其化学结构式为：所述咪唑基希夫碱荧光传感器是通过4-硝基邻苯二胺与水杨醛反应生成苯并咪唑环,通过还原硝基得到氨基,最后通过其氨基与水杨醛反应,合成了一种用于水溶液中铜(II)粒子检测的咪唑基希夫碱荧光传感器。本发明的咪唑基希夫碱荧光传感器对水中的铜(II)粒子具有高的选择性和灵敏度,以及较低的检出限,可应用于纸色谱中定性检测水样中的铜(II)粒子,应用前景广泛。(The invention discloses an imidazolyl Schiff base fluorescence sensor for detecting copper (II) particles in an aqueous solution and a synthesis method thereof, wherein the chemical structural formula of the imidazolyl Schiff base fluorescence sensor is as follows: the imidazolyl Schiff base fluorescence sensor is synthesized by reacting 4-nitrophthalenediamine with salicylaldehyde to generate a benzimidazole ring, reducing nitro to obtain amino, and finally reacting the amino with the salicylaldehyde. The imidazolyl Schiff base fluorescence sensor has high selectivity and sensitivity to copper (II) particles in water and low detection limit, and can be applied to paper chromatographyQualitatively detecting copper (II) particles in a water sample, and has wide application prospect.)

1. An imidazolyl Schiff base fluorescence sensor for detecting copper (II) particles in an aqueous solution, wherein the chemical structural formula of the imidazolyl Schiff base fluorescence sensor is as follows:

2. the method of synthesizing an imidazolyl schiff base fluorescence sensor according to claim 1, wherein the synthetic route is as follows:

the synthesis step comprises the following three steps:

the first step is as follows: 4-nitro o-phenylenediamine and salicylaldehyde are used as raw materials, and the 4-nitro o-phenylenediamine and the salicylaldehyde are subjected to condensation reaction to generate 2- (6-nitro-1H-benzimidazole-2-yl) phenol, namely a compound 1;

the second step is that: carrying out reduction reaction on the compound 2- (6-nitro-1H-benzimidazole-2-yl) phenol obtained in the first step, namely the compound 1, to generate 2- (6-amino-1H-benzimidazole-2-yl) phenol, namely the compound 2;

the third step: and (3) carrying out condensation reaction on the compound 2- (6-amino-1H-benzimidazole-2-yl) phenol obtained in the second step, namely the compound 2 and salicylaldehyde to generate the imidazolyl Schiff base fluorescence sensor, namely the compound 3.

Technical Field

The invention relates to the field of organic small molecule fluorescence sensors, in particular to a 'closed' type imidazolyl Schiff base fluorescence sensor for detecting copper (II) particles in an aqueous solution and a synthetic method thereof.

Background

Copper element is the third most essential trace element in human body, participates in important physiological process of human body, and plays an important role in physiological activity. The concentration of copper (II) particles in human blood is about 15.7-23.6. mu.M. When the concentration of copper (II) particles in the human body exceeds a normal value, imbalance of physiological processes in the human body can be caused, and even serious nervous system diseases can be caused. The world health organization specifies a maximum allowable concentration of copper (II) particles in drinking water of 20 μ M. Therefore, it is important to develop a chemical sensor having high sensitivity and low detection limit for detecting copper (II) particles. Among many detection methods, the fluorescent sensor is simple, rapid and widely used, which makes it possible to develop an environment-friendly fluorescent sensor for real-time monitoring of an actual water sample.

Disclosure of Invention

Therefore, the invention provides an imidazolyl Schiff base fluorescence sensor for detecting copper (II) particles in an aqueous solution and a synthesis method thereof.

The invention relates to an imidazolyl Schiff base fluorescence sensor for detecting copper (II) particles in an aqueous solution, which has the following chemical structure:

the invention provides a synthetic route of an imidazolyl Schiff base fluorescence sensor for detecting copper (II) particles in an aqueous solution, which comprises the following steps:

the synthesis step comprises the following three steps:

the first step is as follows: 4-nitrophthaldiamine and salicylaldehyde are used as raw materials, and the 4-nitrophthaldiamine and the salicylaldehyde undergo a condensation reaction to generate 2- (6-nitro-1H-benzimidazole-2-yl) phenol (namely a compound 1).

The second step is that: and (2) carrying out reduction reaction on the compound 2- (6-nitro-1H-benzimidazole-2-yl) phenol (namely the compound 1) obtained in the first step to generate 2- (6-amino-1H-benzimidazole-2-yl) phenol (namely the compound 2).

The third step: and (3) carrying out condensation reaction on the compound 2- (6-amino-1H-benzimidazole-2-yl) phenol (namely the compound 2) obtained in the second step and salicylaldehyde to generate the imidazolyl Schiff base fluorescence sensor (namely the compound 3).

The imidazolyl Schiff base fluorescence sensor 3 is high in selectivity and sensitivity and low in detection limit (77.01 nM).

Drawings

FIG. 1: histogram of the change in fluorescence intensity of different metal cations in 10 μ M PBS buffer (0.2M, pH 8.0) for compound (3);

FIG. 2: fluorescence titration of copper (II) particle standard solutions in compound (3) 10. mu.M PBS buffer (0.2M, pH 8.0);

FIG. 3: line graph of response duration in compound (3)10 μ M PBS buffer (0.2M, pH 8.0).

Detailed Description

The reagents referred to in the following examples are not specifically described, but are commercial products and of chemical grade purity. In order to more clearly explain the technical problems and technical solutions solved by the present invention, the following embodiments further describe the present invention in detail. The specific embodiments described herein are merely illustrative of the invention and are not intended to be limiting.

Example 1

Preparation of Compound 1

In a 100mL round bottom flask, 1.53g of 4-nitrophthalenediamine, 1.05mL of salicylaldehyde and 20mL of absolute ethanol were added, stirred at room temperature for 5h, filtered, and the filter cake was washed with absolute ethanol and dried to obtain 2.40g of a yellow solid (i.e., compound 1) with a yield of 94%.

HRMS(ESI)C₁₃H₉N₃O₃calcd.for[M+H]⁺256.0722；found:256.2604。

Preparation of Compound 2

50mL of 50% acetic acid was added to a 250mL round-bottom flask, 1.02g of Compound 1 was slowly added, the mixture was stirred at 60 ℃, 1.12g of iron powder was added, the mixture was mechanically stirred for 30min, after the reaction was completed, the reaction mixture was poured into 50mL of ethyl acetate, filtration was performed, the pH of the filtrate was adjusted to 8 with NaOH solution, liquid separation was performed, the organic phase was washed with saturated brine, dried over anhydrous sodium sulfate, filtered, concentrated, and purified by column chromatography using petroleum ether/ethyl acetate as an eluent, to obtain 0.45g of a tan solid (Compound 2) with a yield of 51%.

H HRMS(ESI)m/z calcd.for C₁₃H₁₁N₃O([M+H]⁺):226.0980；found:226.0946。

Preparation of Compound 3

In a 50mL round bottom flask, 0.090g of Compound 2, 42. mu.L of salicylaldehyde and 15mL of anhydrous methanol were added, stirred at room temperature for 5h, filtered, and the filter cake was washed with anhydrous methanol and dried to give 0.12g of a yellow solid (i.e., Compound 3) with a yield of 94%.

HRMS(ESI)m/z calcd.for C₂₀H₁₅N₃O₂([M+H]⁺):330.1243；found:330.1205。

Example 2

Adding 1 equivalent of different metal cation solutions into 310 μ M PBS buffer solution (0.2M, pH 8.0), and measuring the change of fluorescence emission intensity at 360 nm; it was found that compound 3 has good selectivity for copper (II) particles upon addition of 1 equivalent of a solution of different metal cations; when 1 equivalent of copper (II) particles was added to each of the above solutions, the sensor could eliminate the interference and normally detect the copper (II) particles in the aqueous solution, as shown in fig. 1.

Adding copper (II) particle solutions with different concentrations into PBS buffer solution (0.2M, pH 8.0) of compound 310 μ M to perform fluorescence titration experiment; in comparison, compound 3 was found to have practical feasibility as a fluorescence sensor for identifying copper (II) particles, as shown in fig. 2.

Compound 310 μ M was dropped into PBS buffer solution (0.2M, pH 8.0), and copper (II) particle 10 μ M solution was dropped into PBS buffer solution (0.2M, pH 8.0) of compound 310 μ M; in comparison, the identification of copper (II) particles by the compound 3 sensor was stable at 4min and no fluorescence fluctuation occurred for 3h, as shown in fig. 3.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any variations, equivalent alterations and modifications, etc., which are within the spirit and scope of the present invention are encompassed by the present invention.