A perylene tetracarboxylic acid ester fluorescent probe for detecting fluoride ions and a detection method thereof

Abstract

The present invention discloses a perylene tetracarboxylic acid ester fluorescent probe for detecting fluoride ions and a detection method thereof, belonging to the technical field of analytical chemistry. The perylene tetracarboxylic acid ester fluorescent probe contains a copper ion and bipyridine-like complex structure and an O-H group. The fluorescent probe of the present invention is simple to synthesize and convenient to use. The coordination effect of copper ions enhances the ability of the O-H group to donate protons, and can specifically react with fluoride ions. Chloride ions, bromide ions, iodide ions, sulfate ions, acetate ions, perchlorate ions and dihydrogen phosphate ions have no obvious interference on the determination of fluoride ion concentration, and have the characteristics of good selectivity and high sensitivity.

Description

Technical Field

[0001] The present invention belongs to the technical field of analytical chemistry and relates to a perylene tetracarboxylic acid ester fluorescent probe for detecting fluoride ions and a detection method thereof. Background Art

[0002] F - plays an important role in the treatment of osteoporosis and the prevention of dental caries and is widely used in pharmaceutical preparations, toothpaste and even drinking water. However, excessive intake of F - may lead to fluorosis, urolithiasis, renal toxicity changes and even human cancer. At present, there are many analytical methods for the determination of F - , such as spectrophotometry, atomic absorption spectrometry and electrochemistry. However, these methods all have certain limitations, such as complex pretreatment processes and expensive instruments. Therefore, it is very necessary to develop a fluorescent probe technology for detecting F - with low cost, high sensitivity and high selectivity. Perylene tetracarboxylic acid ester (PTAC) and its derivatives have become a research hotspot in the field of fluorescent probes due to their advantages such as good solubility, high fluorescence quantum yield, good thermal and photochemical stability, simple synthesis, high carrier mobility and tunable photophysical properties. The electronic and optical properties of PTAC can be further improved by modifying substituents in the perylene bay region, thereby reversing its normal planar conformation and partially eliminating the tendency of π-π stacking and intermolecular association. Hydroxyl is a highly acidic hydrogen bond donor, and the high basicity of F - in organic solvents will cause deprotonation of the -OH fragment. When -OH is connected to the perylene nucleus, it usually causes significant absorption and fluorescence changes in PTAC. After the O atom of the -OH fragment coordinates with the metal ion copper, the acidity of the -OH fragment is further enhanced and the ability to deprotonate is enhanced, thereby making the detection of F - more sensitive. There has been no report on a PTAC fluorescent probe for detecting F - with a copper chelate in the perylene bay position and an -OH fragment as the recognition group. Summary of the Invention

[0003] In view of the above-mentioned prior art, the present invention provides a perylene tetracarboxylic acid ester fluorescent probe for detecting fluoride ions and a detection method thereof.

[0004] The chemical structural formula of the perylene tetracarboxylic acid ester fluorescent probe provided by the present invention is:

[0005]

[0006] The method for detecting fluoride ions by the perylene tetracarboxylic acid ester fluorescent probe of the present invention:

[0007] Dissolve the probe in dimethyl sulfoxide to prepare a probe solution with a concentration of 1×10-5 mol / L. Add the acetonitrile solution of tetrabutylammonium fluoride to the above probe solution with a pipette and gradually increase the concentration so that the concentration of tetrabutylammonium fluoride after addition is 0.5, 1, 1.5, 2, 2.5, and 3 times the concentration of the probe compound respectively. Measure the fluorescence spectra with an excitation wavelength of 486 nm after each dropwise addition. Use the fluorescence intensity I511nm at 511 nm as the ordinate and the ratio of fluoride ion concentration to probe compound concentration as the abscissa to make a working curve; the working curve is: y = -101.8x + 524.2, R 2 = 0.9976, where y is the fluorescence intensity at 511 nm and x is the ratio of fluoride ion concentration to probe compound concentration, Cl - , Br - , I - , SO 4 2- , AcO - , H 2 PO 4 - , ClO 4 - There is no obvious interference in the determination of fluoride ion concentration.

[0008] Advantages of the present invention:

[0009] A perylene tetracarboxylic acid ester fluorescent probe for detecting fluoride ions and its detection method involved in the present invention have an identification mechanism of intermolecular proton transfer between F - and H atoms (located at the hydroxyl group in the perylene bay position) and subsequent intramolecular charge transfer transition from the O· group to the perylene group. The chelation of O at the perylene bay position hydroxyl and N on the bipyridine-like with Cu(II) enhances the acidity of the -OH fragment and increases its ability to donate protons, making the detection of F - more sensitive. The probe has a red-shifted absorption peak and fluorescence quenching in the presence of F - , with good selectivity. Common anions have no obvious interference in the determination of F - concentration and can be used as a fluorescent probe for F - detection. Brief description of the drawings

[0010] Figure 1 is the molecular structure diagram of the perylene tetracarboxylic acid ester fluorescent probe;

[0011] Figure 2 is the 1 1H NMR spectrum of the perylene tetracarboxylic acid ester fluorescent probe;

[0012] Figure 3 is the FT-IR spectrum of the perylene tetracarboxylic acid ester fluorescent probe;

[0013] Figure 4 Absorption spectra (a) of the perylene tetracarboxylate fluorescent probe of the present invention in DMSO solvent with different amounts of F - (0 - 3.0×10 -5 M) and absorption spectra (b) in the presence of different anions (equivalent amount of 20). The inset shows the corresponding photo under natural light.

[0014] Figure 5 Fluorescence change diagram of the perylene tetracarboxylate fluorescent probe of the present invention in DMSO solvent (concentration 10 µM, excitation wavelength 486 nm) with different amounts of F - (0 - 3.0×10 -5 M), and the inset is the fluorescence photo of the corresponding solution under handheld ultraviolet lamp irradiation (a). The emission peak intensity of the perylene tetracarboxylate fluorescent probe of the present invention at 511 nm and F - (0 - 3.0×10 -5 M) linear correlation diagram (b).

[0015] Figure 6 1H NMR spectra of the perylene tetracarboxylate fluorescent probe of the present invention in DMSO-d6 with different equivalents of F - when 1 H NMR spectra. Detailed implementation manners

[0016] Example 1. Preparation of perylene tetracarboxylate fluorescent probe

[0017] The synthesis route is shown as follows:

[0018]

[0019] Dissolve compound P1 (3.93 g, 5.0 mmol) in 30 ml of dichloromethane, add dropwise copper chloride (0.67 g, 5.0 mmol) dissolved in 10 ml of ethanol, stir, heat under reflux for 3 hours, slowly evaporate the solvent to produce a solid product. Filter and collect the obtained product, and then wash it three times with dichloromethane (1.0 mL) and ethyl acetate (1.0 mL) to obtain the perylene tetracarboxylate fluorescent probe P2 of the present invention (2.17 g, 51%). 1H-NMR (400 MHz, CDCl3 : D-dmso = 50 : 1 δ ppm): 7.91 (1H, d, J = 7.0 Hz), 7.75 (1H, d, J = 8.0 Hz), 7.64 (1H, d, J = 8.0 Hz), 7.52 (1H, m), 7.48 (1H, s), 4.33–4.31 (4H, m), 4.24 - 4.22 (4H, m), 2.60 (3H, s), 1.73–1.69 (8H, m), 1.52–1.38 (8H, m), 1.03–0.84 (12H, m). FT-IR (KBr, cm-1): 3365, 2922, 2854, 2093, 1856, 1650, 1462, 1410, 1314, 1257, 1067, 873, 732, 661, 586, 527, 486, 438。

[0020] The present invention conducted an effect test on the perylene tetracarboxylate fluorescent probe obtained in Example 1:

[0021] 1. Absorption spectral response and selectivity for F - The absorption spectral response and selectivity for F

[0022] The standard solution of tetrabutylammonium fluoride was added to the DMSO solution of the perylene tetracarboxylate fluorescent probe of the present invention, and the interaction between the probe and F - was studied by spectrophotometric titration. The monomeric probe had a strong absorption band at 486 nm ( Figure 4 a). After adding F - (0 - 3.0×10 -5 M) to the probe solution, the absorption band at 486 nm in the probe solution gradually weakened, a new absorption band appeared at 604 nm, a clear isosbestic point was observed at 540 nm, and the orange color of the probe solution changed to dark blue ( Figure 4 a inset). In addition, we also recorded the absorption spectra of P1 and P2 in the presence of other anions ( Figure 4 b). The results showed that in the presence of other anions (Cl - , Br - , I - , SO 4 2- , AcO - , H 2 PO 4 - , ClO 4 -), the absorbance of the probe did not change significantly, which indicates that the probe is sensitive to F - Has higher selectivity.

[0023] 2. For F - The fluorescence spectrum response of

[0024] Under 486nm wavelength light excitation, the monomer probe has a maximum fluorescence emission peak at 511nm. - The concentration increased from 0 to 3×10 -5 M, the degree of fluorescence quenching is about 3 / 5, and the fluorescence color obviously changes from pink to blue-green ( Figure 5 a). Emission peak intensity (I511nm) changes with F - The concentration changes linearly from 0 to 3.0×10-5 M. Figure 5 b is the emission peak of P1 at 574nm and F - The corresponding relationship between the concentration, emission intensity (I574 nm) and F - Concentrations range from 0 to 3×10 -5 M decreases linearly. The linear equation is y = -101.8x + 524.2, (R 2 =0.9976), where y is the fluorescence intensity at 511 nm and x is F - The fluorescent probe of the present invention can be used for F - Fluorescence quantitative analysis.

[0025] 3. Hydrogen Spectrum Titration Study

[0026] use 1 The H NMR titration was used to investigate the relationship between the probe and F - The combination mode. Figure 6 It can be seen that the peak corresponding to the -OH proton in P2 appears at 5.93 ppm, indicating that after the copper chelate is formed, the acidity of the -OH proton is relatively strong. Other researchers have also reached the same conclusion on Ksv. This result supports our view that the coordination of -OH with metal ions will increase the acidity of the -OH proton and enhance the proton-donating ability of the probe. When 3.0 eq of F was added to P2, - After that, the -OH proton signal disappears. The deprotonation of -OH promotes the intramolecular charge transfer of the -OH group to the perylene ring, which also leads to the red shift of the absorption peak of P2.

Claims

1. A method for detecting fluoride ions based on a perylene tetracarboxylic acid ester fluorescent probe, and the chemical structural formula of the perylene tetracarboxylic acid ester fluorescent probe is shown as follows: Characterized in that, The specific steps are as follows: (1) Dissolve the probe in dimethyl sulfoxide to prepare a probe solution with a concentration of 1×10 -5 mol / L; (2) Add the acetonitrile solution of tetrabutylammonium fluoride to the above probe solution with a pipette, and gradually increase the concentration so that the concentrations of tetrabutylammonium fluoride after addition are 0.5, 1, 1.5, 2, 2.5, and 3 times the concentration of the probe compound respectively. Measure the fluorescence spectra with an excitation wavelength of 486 nm after each addition. Use the fluorescence intensity I511nm at 511 nm as the ordinate and the ratio of the fluoride ion concentration to the probe compound concentration as the abscissa to make a working curve; the working curve is: y = -101.8x + 524.2, R 2 = 0.9976, where y is the fluorescence intensity at 511 nm and x is the ratio of the fluoride ion concentration to the probe compound concentration.

2. The method for detecting fluoride ions based on a perylene tetracarboxylic acid ester fluorescent probe according to claim 1, Characterized in that, There is also Cl in the solution - , Br - , I - , SO 4 2- , AcO - , H 2 PO 4 - and ClO 4 - .

Images