阅读说明：本技术 一种基于姜黄素的Schiff碱Fe3+荧光分子探针及其制备方法 (Schiff base Fe based on curcumin3+Fluorescent molecular probe and preparation method thereof ) 是由 姬定西 胡振华 李俊菀 李健博 王园园 刘焕 李朋佳 于 2021-11-08 设计创作，主要内容包括：本发明属于荧光探针领域,特别涉及一种检测Fe～(3+)的荧光探针及其制备方法,具体涉及一种基于姜黄素的Schiff碱Fe～(3+)荧光分子探针,通过姜黄素分子中的羰基与伯胺类化合物进行亲核加成反应制备得到双Schiff碱Fe～(3+)荧光分子探针,其制备过程简单,反应条件容易控制,制备的荧光探针具有优良的光学性能和化学稳定性,在pH为4～9范围内对Fe～(3+)有良好的识别性能,抗干扰能力强,可用于火电厂水汽系统痕量铁的分析检测。(The invention belongs to the field of fluorescent probes, and particularly relates to a method for detecting Fe 3+ In particular to a Schiff base Fe based on curcumin and a preparation method thereof 3+ A fluorescent molecular probe, which is prepared by nucleophilic addition reaction of carbonyl in curcumin molecules and primary amine compounds to obtain bis-Schiff base Fe 3+ The fluorescent molecular probe is simple in preparation process and easy to control reaction conditions, the prepared fluorescent probe has excellent optical performance and chemical stability, and can be used for treating Fe within the pH range of 4-9 3+ The method has good identification performance and strong anti-interference capability, and can be used for analyzing and detecting trace iron in a water vapor system of a thermal power plant.)

1. Schiff base Fe based on curcumin³⁺The fluorescent molecular probe is characterized in that the molecular structure of the fluorescent molecular probe is as follows:

2. a curcumin-based Schiff base Fe as claimed in claim 1³⁺The preparation method of the fluorescent molecular probe is characterized in that the preparation route is as follows:

the preparation method comprises the following steps:

step 1), mixing the mixture with a millimole ratio of 8-10: adding 24-30 parts of curcumin and 2-aminomethyl pyridine into an organic solvent, stirring and mixing uniformly under the protection of nitrogen, heating and refluxing for 4-6 hours, cooling to room temperature, and separating out yellow needle crystals;

step 2) filtering, washing the precipitate for 3-5 times by using deionized water, recrystallizing by using ethanol, and drying in vacuum to obtain Schiff base Fe based on curcumin³⁺The yield of the fluorescent molecular probe CURB is 80-90%.

3. A Schiff base Fe based on curcumin as claimed in claim 2³⁺The preparation method of the fluorescent molecular probe is characterized in that the organic solvent in the step 1) is one of absolute methanol and absolute ethanol, and the millimole ratio of the organic solvent to curcumin is 1000-1500: 8 to 10.

4. A Schiff base Fe based on curcumin as claimed in claim 2³⁺The preparation method of the fluorescent molecular probe is characterized in that the heating reflux temperature in the step 1) is 80-90 ℃.

5. A Schiff base Fe based on curcumin as claimed in claim 2³⁺The preparation method of the fluorescent molecular probe is characterized in that the deionized water hydrogen conductivity in the step 2) is 0.055-0.070 muS/cm.

6. A Schiff base Fe based on curcumin as claimed in claim 2³⁺The preparation method of the fluorescent molecular probe is characterized in that the vacuum drying temperature in the step 2) is 60-70 ℃, and the drying time is 2-4 h.

7. A curcumin-based Schiff base Fe as claimed in claim 1³⁺Fluorescent molecular probe for detecting Fe in water³⁺。

Technical Field

The invention belongs to the field of fluorescent probes, and particularly relates to Schiff base Fe based on curcumin³⁺Fluorescent molecular probe and its preparation method.

Background

The iron content in the water vapor system of the thermal power plant is an important basis for evaluating the corrosion and scaling conditions of the thermodynamic system of the power generation operation unit, and is one of important monitoring indexes in daily production of the thermal power plant. At present, methods for measuring total iron in feed water, furnace water and hydrophobic water in power production are phenanthroline spectrophotometry (GB/T14427-2008) and graphite furnace atomic absorption method (DL/T955-2005). The phenanthroline spectrophotometry is a traditional manual analysis method, the method is complex in operation, low in analysis efficiency, narrow in linear range, easy to pollute sample water, low in detection precision especially for iron ions with low concentration (less than 10 mu g/L), and inevitable in human error, so that the accuracy is poor. The graphite furnace atomic absorption method uses expensive instruments and has high operation and maintenance requirements. Therefore, the research on the fluorescent molecular probe capable of being used for iron ion detection has important significance for measuring iron in a power plant.

At present, there is reported Fe³⁺The fluorescent molecular probes mainly comprise rhodamine B type, pyridine type, naphthalimide type and coumarin type from the structural point of view, and the molecular probes are in Fe³⁺The detection shows good performance, but the defects of the detection are that most probes have multiple synthesis steps, complicated process, high cost and high toxicity. Therefore, the Fe with simple structure and excellent performance is designed and synthesized³⁺Fluorescent molecular probes are an important trend.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides Schiff base Fe based on curcumin³⁺The fluorescent molecular probe has excellent optical performance, good chemical stability and Fe tolerance³⁺Has high selectivity and sensitivity, and can be used for treating Fe²⁺And Fe³⁺Discrimination is performed.

In order to solve the technical problems, the invention adopts the following technical scheme:

schiff base Fe based on curcumin³⁺The fluorescent molecular probe has the following molecular structure:

the Schiff base Fe based on curcumin³⁺The preparation method of the fluorescent molecular probe comprises the following preparation lines:

the preparation method comprises the following steps:

step 1), mixing the mixture with a millimole ratio of 8-10: adding 24-30 parts of curcumin and 2-aminomethyl pyridine into an organic solvent, stirring and mixing uniformly under the protection of nitrogen, heating and refluxing for 4-6 hours, cooling to room temperature, and separating out yellow needle crystals;

step 2) filtering, washing the precipitate for 3-5 times by using deionized water, recrystallizing by using ethanol, and drying in vacuum to obtain Schiff base Fe based on curcumin³⁺The yield of the fluorescent molecular probe CURB is 80-90%.

The organic solvent in the step 1) is one of absolute methanol and absolute ethanol, and the millimole ratio of the organic solvent to curcumin is 1000-1500: 8 to 10.

In the step 1), the heating reflux temperature is 80-90 ℃.

And 2) the hydrogen conductivity of the deionized water is 0.055-0.070 mu S/cm.

The vacuum drying temperature is 60-70 ℃, and the drying time is 2-4 h.

The obtained Schiff base Fe based on curcumin³⁺Method for detecting Fe in water by fluorescent molecular probe³⁺The specific method comprises the following steps:

1mL (1X 10)^-4mol/L) fluorescent molecular probes are sequentially added into a plurality of 10mL volumetric flasks, and then 1mL and 0-5 multiplied by 10 are sequentially added^-5mol/L Fe³⁺Aqueous solution, 0.0Adjusting the pH value of the mixed solution to 4-9 by using a 01mol/L hydrochloric acid solution, fixing the volume to 10mL scale by using deionized water, shaking up, standing for 5-10 min, and testing the fluorescence intensity of the mixed solution by using a fluorescence spectrophotometer with 340-400 nm as an excitation wavelength, 1-2.5/2-5 nm of a slit and 380-460 nm as emission wavelengths to obtain the corresponding fluorescence intensity.

The Schiff base substance has an extremely simple C ═ N functional group structure, is easy to synthesize, provides conditions for coordination and chelation with metal ions by lone pair electrons in an N atom, and has the advantage of specific metal ion recognition. Curcumin is a pigment extracted from plant turmeric, has physiological activities such as oxidation resistance, cancer resistance and the like, is safe and non-toxic, has a symmetrical carbonyl molecular structure, can be subjected to certain structural modification, can be subjected to nucleophilic addition reaction on carbonyl in curcumin molecules and primary amine compounds to form Schiff base, and can realize fluorescent recognition when being chelated with metal ions. Compared with the prior art, the invention has the following beneficial effects: the invention uses the safe and nontoxic natural extract curcumin, prepares the double Schiff base fluorescent molecular probe by utilizing the reaction of carbonyl in the molecule of the curcumin and amino in the molecule of 2-aminomethyl pyridine, has the advantages of one-step synthesis, simple process, easy control, high synthesis yield, convenient large-scale production and Fe³⁺Has high selectivity, sensitivity and anti-interference performance, and can be used for treating Fe²⁺And Fe³⁺Discrimination is performed.

Drawings

FIG. 1 shows the molecular structure of the fluorescent molecular probe (CURB) provided by the present invention.

FIG. 2 is a synthetic route of the fluorescent molecular probe (CURB) provided by the present invention.

FIG. 3 shows the fluorescent molecular probes (CURB) vs. Fe provided by the present invention³⁺Selectivity of fluorescence detection.

FIG. 4 shows the detection of Fe by common ion pair fluorescent molecular probe (CURB) provided by the invention³⁺The influence of (c).

FIG. 5 shows the reaction time for detecting Fe with the fluorescent molecular probe (CURB) provided by the present invention³⁺The influence of (c).

FIG. 6 shows the reaction temperature versus fluorescent molecular probe (CURB) provided by the present inventionDetection of Fe³⁺The influence of (c).

FIG. 7 shows the detection of Fe by fluorescent molecular probes (CURB) provided by the present invention in response to pH³⁺The influence of (c).

FIG. 8 shows fluorescent molecular probes (CURB) and Fe provided by the present invention³⁺The complexing mode of (1).

FIG. 9 shows the fluorescent molecular probes (CURB) vs. Fe provided by the present invention³⁺Detection limit of the assay curve.

Detailed Description

The preparation and use of the fluorescent molecular probe (CURB) provided by the present invention will be specifically described below with reference to specific examples and drawings.

As shown in figure 1, the invention is based on Schiff base Fe of curcumin³⁺Molecular structure of fluorescent molecular probes.

Example 1

As shown in figure 2, 8.2mmol curcumin and 25.3mmol 2-aminomethyl pyridine are added into 1100mmol anhydrous methanol, stirred and mixed evenly under the protection of nitrogen, heated and refluxed for 4h at 80 ℃, cooled to room temperature, and yellow needle-shaped crystals are separated out. Filtering, washing the precipitate with deionized water with hydrogen conductivity of 0.056 μ S/cm for 3 times, recrystallizing with ethanol, and vacuum drying at 60 deg.C for 2 hr to obtain Schiff base Fe3+ fluorescent molecular probe (CURB) based on curcumin with yield of 83.2%.

Example 2

As shown in figure 2, 9.1mmol of curcumin and 27.8mmol of 2-aminomethyl pyridine are added into 1320mmol of absolute ethyl alcohol, stirred and mixed uniformly under the protection of nitrogen, heated and refluxed for 5h at 85 ℃, cooled to room temperature, and yellow needle-shaped crystals are separated out. Filtering, washing precipitate with deionized water with hydrogen conductivity of 0.06 μ S/cm for 4 times, recrystallizing with ethanol, and vacuum drying at 65 deg.C for 3 hr to obtain Schiff base Fe based on curcumin³⁺Fluorescent molecular probe (CURB), yield 85.7%.

Example 3

As shown in figure 2, 9.8mmol of curcumin and 29.5mmol of 2-aminomethyl pyridine are added into 1475mmol of absolute ethanol, stirred and mixed uniformly under the protection of nitrogen, heated and refluxed for 6h at 90 ℃, cooled to room temperature, and yellow needle-shaped crystals are separated out. For treatingFiltering, washing precipitate with deionized water with hydrogen conductivity of 0.068 μ S/cm for 5 times, recrystallizing with ethanol, and vacuum drying at 70 deg.C for 4 hr to obtain Schiff base Fe based on curcumin³⁺Fluorescent molecular probe (CURB), yield was 86.8%.

Example 4

Fluorescent molecular Probe (CURB) vs. Fe obtained in example 1³⁺Selectivity of fluorescence detection.

5mL (1.0X 10)^-4mol/L) fluorescent molecular probe in a 10mL volumetric flask, and diluting the fluorescent molecular probe to 5.0 × 10 concentration by deionized water^-5mol/L for standby. Deionized water is used for preparing a metal ion solution with the concentration of 0.05mol/L, 0.2mL and 0.05mol/L of the metal ion solution are transferred into a volumetric flask by a liquid transfer machine, the metal ion concentration is 20 times of the probe concentration, the response of the probe to different metal ions is detected by exciting light with the wavelength of 380nm, and the measurement result is shown in figure 3. The results show that: CUBR to Fe³⁺Has strong selective recognition function.

Example 5

Detection of Fe by common ion on fluorescent molecular Probe (CURB) obtained in example 1³⁺Interference experiments of (4).

To further investigate other metal ions (Ca)²⁺、Pb²⁺、Cu²⁺、Ba²⁺、Cd²⁺、Zn²⁺、Ni²⁺、Co²⁺、Fe²⁺、Mn^{2 +}、Hg²⁺、Li⁺、Ag⁺、Mg²⁺、K⁺、Na⁺、Cr³⁺、Al³⁺) For Fe³⁺Interference of (2) to various metal ion pairs Fe³⁺The competition relationship of (2) was measured and blank was measured, and the results are shown in FIG. 4. The results show that Fe is not added³⁺Before, the CURB solutions of each metal ion had similar fluorescence intensities when 2.0X 10 was added^-5mol/L of Fe³⁺Then, fluorescence quenching occurred. This indicates that CURB is on Fe³⁺The identification has good selectivity and anti-interference capability.

Example 6

Reaction timeDetection of Fe for fluorescent molecular Probe (CURB) obtained in example 1³⁺The influence of (c).

A10 mL volumetric flask was taken and 5mL (1.0X 10)^-4mol/L) fluorescent probe molecule mother liquor and 0.2mL of 0.05mol/L Fe is removed by a liquid transfer device³⁺Adding into a volumetric flask, adding deionized water to constant volume, shaking, and rapidly performing fluorescence test to test CURB + Fe within 30min³⁺The fluorescence intensity of the system changes. It can be seen from FIG. 5 that Fe is added³⁺After 2min, the fluorescence was almost completely quenched, from which Fe was seen³⁺The identification of the CURB is rapid. In order to fully guarantee the effect, the fluorescence test is carried out after 5 min.

Example 7

Reaction temperature detection of Fe for fluorescent molecular Probe (CURB) obtained in example 1³⁺The influence of (c).

A10 mL volumetric flask was taken and 1mL (1.0X 10) was pipetted^-4mol/L) fluorescent probe molecule mother liquor and 0.2mL of 0.05mol/L Fe is removed by a liquid transfer device³⁺Adding into a volumetric flask, then using deionized water to perform constant volume, shaking up, and rapidly performing fluorescence test to test the CURB + Fe within the temperature range of 10-60 DEG C³⁺The fluorescence intensity of the system was varied, and the results are shown in FIG. 6. From FIG. 6, it can be seen that temperature vs. Fe³⁺The identification of CURB has little influence, so the fluorescence test is carried out at 20-30 ℃.

Example 8

Reaction pH detection of Fe on fluorescent molecular Probe (CURB) obtained in example 1³⁺The influence of (c).

Investigating the pair of Fe by CURB within the pH range of 4-9³⁺The results of the detection of (2) are shown in FIG. 7. As can be seen from FIG. 7, the fluorescence intensity of the CURB system is almost unchanged within pH 4-9, while Fe is added³⁺The fluorescence intensity of the latter system is obviously weakened, which indicates that Fe is added³⁺Post CURB and Fe³⁺The complex is quenched in fluorescence, and the fluorescence intensity is stable at pH 4-9, so that the CURB is suitable for Fe at pH 4-9³⁺And (4) detecting fluorescence.

Example 9

Fluorescent molecular Probe (CURB) obtained in example 1 with Fe³⁺Complex ofFormula (II)

CURB and Fe were measured by the constant variation of the amounts of the substances (Job-Plot method)³⁺The results are shown in FIG. 8. As can be seen from FIG. 8, the intersection of the two straight lines is about 0.5, indicating that CURB and Fe are present³⁺The complex ratio of (A) is 1: 1.

example 10

Fluorescent molecular Probe (CURB) vs. Fe obtained in example 1³⁺Linear relationship of concentration.

Taking different low-concentration Fe at room temperature³⁺Drawing a standard working curve by using a fluorescence spectrometer as shown in figure 9, wherein the result shows that the fluorescence intensity of the solution is 0-7 multiplied by 10^-6In a linear relationship in the range of mol/L to Fe³⁺Has a detection limit of 1.58X 10^-7mol/L(R²＝0.9927)。

In summary, although the present invention has been described in detail with reference to the specific embodiments, the description is illustrative, and those skilled in the art can make various modifications and changes based on the principle without departing from the invention, and the scope of the invention is defined by the appended claims.