A fluorescence sensor based on bisnaphthoylhydrazone functionalization for single selective recognition of iron ions, and its synthesis and application

Abstract

The present invention provides a fluorescence sensor BNH based on binaphthoylhydrazone functionalization that can selectively recognize iron ions alone. This sensor is synthesized from 1-naphthaleneacetylhydrazine and terephthalaldehyde. In the DMSO-H2O solution of the fluorescence sensor BNH, only the addition of iron ions can quench the fluorescence of the fluorescence sensor BNH, while it has no response to other cations (Zn 2+ , Pb 2+ , Cd 2+ , Ni 2+ , Co 2+ , Fe 3+ , Hg 2+ , Ag + , Ca 2+ , Cu 2+ , Mg 2+ , Cr 3+ , Ba 2+ , Tb 3+ , Eu 4+ , La 3+ and Al 3+ ). Therefore, the sensor BNH has the performance of selectively recognizing iron ions alone, and the detection limit is 4.46×10 ‑7 M. The recognition of iron ions by this sensor is achieved through coordination and cation-π interactions.

Description

Technical Field

[0001] The present invention relates to a synthesis method of a fluorescent sensor based on binaphthoylhydrazone functionalization capable of highly sensitive and single-selective recognition of iron ions; the present invention also relates to the application of the fluorescent sensor in the fluorescent recognition of iron ions in a DMSO-H2O solution, belonging to the fields of chemical synthesis and ion detection. Background Art

[0002] Iron ions are one of the important transition metal ions and play a crucial role in aspects such as oxygen transport, muscle contraction, DNA and RNA synthesis, nerve conduction, enzyme synthesis, and regulation of cellular acid-base balance. Iron ions are biologically important, but both excessive and deficient iron ions can cause serious health problems. Iron overload in the human body can cause serious diseases such as osteoporosis, cancer, organ dysfunction, hemochromatosis, Alzheimer's disease, and Parkinson's disease, while iron deficiency can cause anemia and affect various cell metabolic processes.

[0003] Common methods for detecting iron ions include atomic absorption spectrometry, electrochemistry, and inductively coupled plasma mass spectrometry, etc., but most of these methods are costly and operationally complex. Summary of the Invention

[0004] The purpose of the present invention is to provide a fluorescent sensor based on binaphthoylhydrazone functionalization capable of single-selective recognition of iron ions;

[0005] Another purpose of the present invention is to provide a synthesis method of the above fluorescent sensor;

[0006] Another purpose of the present invention is to provide the application of the fluorescent sensor in the recognition of iron ions.

[0007] I. Fluorescent Sensor and Its Synthesis

[0008] The fluorescent sensor based on binaphthoylhydrazone functionalization capable of single-selective recognition of iron ions in the present invention has a molecular formula of C 32 H 26 N4O2, labeled as: BNH, and its structural formula is:

[0009] .

[0010] The preparation method of the fluorescent sensor of the present invention includes the following steps:

[0011] (1) Preparation of 1-naphthylacetylhydrazine: Using methyl 1-naphthoate and hydrazine hydrate as substrates, absolute ethanol as a solvent, reacting at 85 °C for 24 h, and after the reaction is completed, washing with water, and the obtained white solid is 1-naphthylacetylhydrazine; wherein, the molar ratio of the substrate methyl 1-naphthoate to hydrazine hydrate is 1:1 to 1:2;

[0012] (2)Synthesis of Fluorescent Sensor BNH: Using methyl 1-naphthaleneacetate and terephthalaldehyde as substrates, absolute ethanol as the solvent, adding acetic acid, reacting at 80-90 °C for 20-25 h. After the reaction, a white solid is obtained, which is washed with hot ethanol, and the obtained product is the fluorescent sensor BNH; among them, the molar ratio of the substrate terephthalaldehyde to 1-naphthylacetylhydrazine is 1:2-1:4.

[0013] The synthesis route of the above-prepared fluorescent sensor is as follows:

[0014]

[0015] The mass spectrum and hydrogen spectrum of Intermediate 1 (1-naphthylacetylhydrazine) are shown in Figure 1 and Figure 2 . The mass spectrum and hydrogen spectrum of the fluorescent sensor molecule BNH are shown in Figure 3 and Figure 4 .

[0016] II. Application of Fluorescent Sensor in Detecting Iron Ions

[0017] 1. Fluorescent Properties of Fluorescent Sensor BNH

[0018] The research on the fluorescent properties of the fluorescent sensor BNH shows that the fluorescent sensor BNH has good solubility in DMSO-H2O solution. When the excitation wavelength is 310 nm, the sensor molecule BNH has strong fluorescence emission properties.

[0019] 2. Recognition of Iron Ions by Fluorescent Sensor BNH

[0020] In the DMSO-H2O solution (C BNH = 1×10 -5 M) of the fluorescent sensor BNH, 20-fold equivalents (relative to the fluorescent sensor BNH) of 0.1 M Zn 2+ , Pb 2+ , Cd 2+ , Ni 2+ , Co 2+ , Fe 3+ , Hg 2+ , Ag + , Ca 2+ , Cu 2+ , Mg 2+ , Cr 3+ , Ba 2 + , Tb 3+ , Eu 4+ , La 3+ , Al 3+ aqueous solutions are added, and the fluorescence changes of the solution are observed. Figure 5Fluorescence spectra of DMSO-H2O solutions of the sensor molecule BNH of the present invention with different cations added (λ ex = 310 nm). It was found that only the addition of iron ions could quench the fluorescence of the DMSO-H2O solution of the fluorescent sensor BNH. The addition of other cations could not quench the fluorescence of the DMSO-H2O solution of the fluorescent sensor BNH, indicating that the fluorescent sensor BNH has a single selective recognition performance for iron ions.

[0021] Meanwhile, in order to study the interference of other cations on the recognition of iron ions by the sensor BNH, we conducted an anti-interference experiment. Figure 6 Anti-interference diagrams of different cations added to the DMSO-H2O solution of the sensor molecule BNH after adding iron ions. The results show that the presence of other cations has no obvious interference on the recognition of iron ions by the fluorescent sensor BNH (as Figure 6 shown).

[0022] The fluorescence titration experiment shows that the lowest detection limit of the fluorescent sensor BNH for iron ions is 4.46×10 -7 M (as Figure 7 , 8 shown).

[0023] 3. Analysis of the recognition mechanism

[0024] The mechanism of the fluorescent sensor BNH recognizing iron ions was studied by infrared spectroscopy. The infrared spectra of the host BNH before and after adding iron ions were measured respectively, and the changes in the infrared spectra were compared. Figure 9 Infrared spectra of the sensor molecule BNH of the present invention before and after adding iron ions. It can be seen from Figure 9 that with the addition of iron ions, the NH peak on BNH disappears, and the C=O signal peak changes from 1668 to 1670 cm -1 , which is attributed to the coordination between iron ions and N-H and C=O on the sensor molecule BNH, indicating that BNH binds to iron ions through cation-π interaction. Therefore, the fluorescence of the DMSO-H2O solution of the fluorescent sensor BNH is quenched after adding iron ions.

[0025] Meanwhile, the mechanism of the fluorescent sensor BNH recognizing iron ions was studied by theoretical calculation. The frontier molecular orbitals (highest occupied molecular orbital and lowest unoccupied molecular orbital, HOMO and LUMO) illustrate the electronic structure properties of BNH and BNH-Fe 3+ . As Figure 10 shown, the HOMO orbital of BNH is mainly distributed on the naphthalene ring, and the LUMO orbital is located on the hydrazone group and the benzene ring; while BNH-Fe 3+The HOMO orbitals of the complex are mainly distributed on the naphthalene ring and benzene ring, and the LUMO orbitals are located on the naphthalene ring. This indicates that the binding of iron ions to BNH forces BNH to redistribute the electron density to form a stable complex. In addition, BNH-Fe 3+ has a smaller energy gap than BNH, which also indicates that electrons are redistributed during the binding process. It can be seen that the electron redistribution after BNH binds to iron ions leads to fluorescence quenching. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is the mass spectrum of Intermediate 1 of the present invention;

[0027] Figure 2 is the hydrogen spectrum of Intermediate 1 of the present invention;

[0028] Figure 3 is the mass spectrum of the sensor molecule BNH of the present invention;

[0029] Figure 4 is the hydrogen spectrum of the sensor molecule BNH of the present invention;

[0030] Figure 5 is the full-scan curve of different cations added to the DMSO-H2O solution of the sensor molecule BNH of the present invention (λ ex = 310 nm);

[0031] Figure 6 is the anti-interference diagram of other cations added after adding iron ions to the DMSO-H2O solution of the sensor molecule BNH of the present invention (λ ex = 310 nm);

[0032] Figure 7 is the fluorescence titration diagram of adding iron ions to the DMSO-H2O solution of the sensor molecule BNH of the present invention (λ ex = 310nm);

[0033] Figure 8 is the lowest detection limit of adding iron ions to the DMSO-H2O solution of the sensor molecule BNH of the present invention;

[0034] Figure 9 is the infrared spectrum diagram of the sensor molecule BNH of the present invention before and after adding iron ions;

[0035] Figure 10 is the quantitative calculation frontier molecular orbital diagram of the sensor molecule BNH of the present invention before and after adding iron ions. DETAILED DESCRIPTION OF THE INVENTION

[0036] The preparation of the fluorescence sensor molecule BNH of the present invention and its application in fluorescence recognition of iron ions will be further described below through specific examples.

[0037] Example 1. Fluorescent sensor BNH

[0038] (1) Synthesis of 1-naphthaleneacetylhydrazine: Weigh 1 g (5 mmol) of methyl 1-naphthaleneacetate and 5 mmol of hydrazine hydrate (≥ 85%), add them to 50 ml of anhydrous ethanol solvent, and react at 85 °C for 24 h. After the reaction, wash the white solid with water, and the obtained product is 1-naphthaleneacetylhydrazine. The yield is 85%;

[0039] (2) Synthesis of fluorescent sensor BNH: Weigh 1 g (5 mmol) of 1-naphthaleneacetylhydrazine and 1.48 g (11 mmol) of terephthalaldehyde, add them to 50 ml of anhydrous ethanol solvent, add a trace amount (0.5 ml) of acetic acid, and react at 85 °C for 24 h. After the reaction, a white solid is obtained, which is washed with hot ethanol, and the obtained product is fluorescent sensor BNH. The yield is 70%.

[0040] The mass spectrum and hydrogen spectrum of 1-naphthaleneacetylhydrazine are shown in Figure 1 and Figure 2 . The mass spectrum and hydrogen spectrum of the fluorescent sensor molecule BNH are shown in Figure 3 and Figure 4 .

[0041] Example 2. Recognition of iron ions by fluorescent sensor BNH

[0042] Transfer 2 mL of the DMSO-H2O solution of fluorescent sensor BNH (C BNH = 1×10 -5 M) into a series of fluorescence tubes, and respectively add aqueous solutions of Zn 2+ , Pb 2+ , Cd 2+ , Ni 2+ , Co 2+ , Fe 3+ , Hg 2+ , Ag + , Ca 2+ , Cu 2+ , Mg 2+ , Cr 3+ , Ba 2+ , Tb 3+ , Eu 4+ , La 3+ , Al 3+ (C = 0.1 M). If the fluorescence of the DMSO-H2O solution of the sensor molecule BNH is quenched, it indicates that the added solution is an iron ion solution; if the fluorescence of the sensor molecule is not quenched, it indicates that the added solution is not an iron ion.

Claims

1. Application of a fluorescence sensor based on bisnaphthoylhydrazone functionalization for single-selective recognition of iron ions in the recognition of iron ions, characterized in that: The molecular formula of the fluorescent sensor is C 32 H 26 N4O2, and its structural formula is: 。 2. Application of the fluorescence sensor based on binaphthoylhydrazone functionalization for single selective recognition of iron ions in the recognition of iron ions, characterized in that: In the DMSO-H2O solution of the fluorescence sensor, Zn 2+ , Pb 2+ , Cd 2+ , Ni 2+ , Co 2+ , Fe 3+ , Hg 2+ , Ag + , Ca 2+ , Cu 2+ , Mg 2+ , Cr 3+ , Ba 2+ , Tb 3+ , Eu 4+ , La 3+ , Al 3+ aqueous solutions were added. Only the addition of iron ions can quench the fluorescence of the DMSO-H2O solution of the fluorescence sensor.

3. Application of the fluorescence sensor based on binaphthoylhydrazone functionalization for single selective recognition of iron ions in the recognition of iron ions, characterized in that: Synthesis method of a fluorescent sensor, comprising the following steps: Using 1-naphthalene acetylhydrazine and terephthalaldehyde as substrates, absolute ethanol as a solvent, adding acetic acid, reacting at 80-90 °C for 20-25 h. After the reaction ends, a white solid is obtained, which is rinsed with hot ethanol, and the obtained product is the fluorescent sensor.

4. Use of the fluorescent sensor based on binaphthoylhydrazone functionalization for single-selective recognition of iron ions in the recognition of iron ions, characterized in that: The molar ratio of terephthalaldehyde to 1-naphthalene acetylhydrazine is 1:2 to 1:4.

Images