BODIPY sodium pyridine disulfonate fluorescent probe and its synthesis method and application

Abstract

The present invention belongs to the technical field of fluorescent materials, and in particular to a kind of BODIPY sodium pyridine disulfonate fluorescent probe and its synthesis method and application. The synthesis method of the fluorescent probe is simple, low cost, high sensitivity, good selectivity, strong stability, and wide detection range; by the combination of iron ions to sulfonate and the quenching of fluorescent probes, there is also the response of pyrrole to pH, the iron ion content in the water medium is detected and the pH changes are responded to. When the probe is 6.59 and 4.32 in pH, the detection limits of iron ions are 0.037μM and 0.034μM respectively, and between 6.0μM~58.0μM, the detection of iron ions is in a good linear relationship, and is sensitive to pH values ​​within the range of 1.96-6.59. The response to pH and the detection of iron ions both achieve obvious polychromatic changes, and have great potential in detecting iron ions.

Description

Technical Field

[0001] The invention belongs to the technical field of fluorescent materials, and specifically relates to a BODIPY sodium pyridinedisulfonate fluorescent probe and a synthesis method and application thereof. Background Art

[0002] pH plays an integral role in applications ranging from life sciences to the environment to industry. Taking mitochondria as an example, during mitophagy, the pH of damaged mitochondria in lysosomes changes from ~8 (normal physiological conditions) to ~4.5 (weakly acidic). This change is particularly pronounced, so it can be seen that pH is an important parameter for measuring mitochondrial damage during mitophagy. Therefore, it is crucial to construct an effective method for measuring pH changes. Observing the color changes of litmus paper and pH paper is undoubtedly the most convenient and direct method. However, these methods are insensitive to small changes in pH and have difficulties in obtaining optimal and accurate results. In order to obtain more effective and accurate methods, many analytical and detection methods for monitoring pH changes have been widely explored. Among these methods, optical chemical sensors are considered to be sensors that can see and hear beyond human eyes and ears.

[0003] As the fourth most abundant metal in the earth's crust, iron (Fe 3+ ) is the most widely distributed transition metal element in the environment and organisms, and is also an essential component involved in many biochemical processes such as oxygen transport, muscle function, DNA / RNA synthesis, metabolism, and electron transfer. In addition, Fe 3+ The concentration of Fe is considered an important parameter for human health monitoring, as its overload and deficiency can disrupt cellular homeostasis and lead to various diseases such as anemia, arthritis, fatigue, reduced immunity, and even cancer. 3+ It can also relieve the symptoms of dentin hypersensitivity caused by occlusion of dentinal tubules. 3+ The intake concentration is extremely important for human health. Under normal circumstances, 0.2-0.3 mg L is allowed to be added to drinking water. -1 Fe 3+ According to the reported method for detecting Fe 3+ A chemical sensor that can sensitively recognize Fe 3+ , but rarely cause multicolor detection of aqueous solutions, because many of them are organic and can only be used in pure organic solvents or organic solutions containing a small amount of water. 3+ Detection.

[0004] BODIPY derivatives are used as one of the best candidates for fluorophores due to their good selectivity, high fluorescence quantum yield and excellent optical stability. However, the poor water solubility of BODIPY limits its application in water and organisms. Summary of the invention

[0005] The purpose of the present invention is to overcome the defects in the prior art and provide a BODIPY sodium pyridine disulfonate fluorescent probe and its synthesis method, application and selection of optimal conditions.

[0006] To achieve the above purpose, the present invention designs a BODIPY sodium pyridine disulfonate fluorescent probe, referred to as BODIPY(SO3Na)2, wherein fluoroboron dipyrrole is referred to as BODIPY. The BODIPY sodium pyridine disulfonate fluorescent probe is composed of two sulfonate groups functionalized on fluoroboron dipyrrole and a pyridine group located in the middle position, and its structural formula is as follows:

[0007]

[0008] The synthesis method of BODIPY sodium pyridine disulfonate fluorescent probe comprises the following steps:

[0009] S1: Prepare BODIPY-PY, introduce pyridine into the middle position of fluoroboranedipyrrole to obtain BODIPY-PY.

[0010] S2: Prepare BODIPY(SO3Na)2 by adding fresh chlorosulfonic acid dropwise to BODIPY-PY at about -20°C under N2 atmosphere, then collect the crude product by filtration, dissolve in aqueous sodium bicarbonate solution, evaporate to dryness, and then reprecipitate from brine. Purify BODIPY(SO3Na)2 by silica gel column chromatography.

[0011] The specific operation is: 3.5 equivalents (about 1.473mmol) of fresh chlorosulfonic acid dissolved in 4mL of anhydrous dichloromethane are dropped into a solution of BODIPY-PY (0.1370g, 0.421mmol) dissolved in 2mL of anhydrous dichloromethane for 10 minutes. The reaction mixture is placed in an ice NaCl bath during the addition process, and the temperature is kept at about -20°C under a N2 atmosphere. After the chlorosulfonic acid is added dropwise, the cooling bath is removed, the reaction mixture is returned to room temperature, and stirred for another 6h. Filter and collect, and then dissolve in a small amount of sodium bicarbonate aqueous solution. Then, evaporate to dryness, and reprecipitate in saturated brine to obtain a crude product. BODIPY(SO3Na)2 is obtained by silica gel rapid column chromatography.

[0012] In order to facilitate the application of the above-mentioned BODIPY sodium pyridine disulfonate fluorescent probe, an application of a BODIPY sodium pyridine disulfonate fluorescent probe is proposed, and the BODIPY sodium pyridine disulfonate fluorescent probe is used as a response to pH changes and Fe under different pH conditions. 3+ Detection.

[0013] In order to facilitate the selection of the optimal conditions for the above-mentioned BODIPY sodium pyridine disulfonate fluorescent probe, an optimal scheme for detection conditions is proposed, including the following conditions:

[0014] C1: When measuring pH, the pH value is in the range of 1.96-6.59. Too strong acidity or too strong alkalinity will affect the linear relationship between the fluorescence intensity ratio and pH, thereby affecting the detection performance.

[0015] C2: When measuring the iron ion concentration, the pH is 6.59 or 4.32. Other pH values ​​will affect the selectivity and specificity of the BODIPY sodium pyridine disulfonate fluorescent probe for iron ions, thereby affecting the detection performance.

[0016] C3: When measuring iron ion concentration, the concentration of BODIPY sodium pyridine disulfonate fluorescent probe is 10 μM. Too high or too low concentration will affect the fluorescence density and thus affect the detection performance.

[0017] The advantages and beneficial effects of the present invention are:

[0018] The present invention proposes a novel BODIPY sodium pyridine disulfonate fluorescent probe. The synthetic method of the fluorescent probe is simple, the implementation feasibility is high, the cost is low, the sensitivity, selectivity, stability are high, the detection range is wide, and it is the fluoroboron dipyrrole derivative with the highest hydrophilicity so far. The fluorescent probe detects the iron ion content in the water medium and responds to pH changes. It can be applied to the detection of the iron ion content in real water samples, and has application potential in environmental, living system and industrial pH measurement. Ultraviolet absorption, fluorescence excitation and emission spectra show that the fluorescent probe has a maximum absorption peak at 500nm, and the optimal excitation and emission spectra reach maximum values ​​at 350 and 511nm, respectively. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The BODIPY sodium pyridine disulfonate fluorescent probe in Example 1 was obtained using a Bruker Avance nuclear magnetic resonance spectrometer (400 MHz, MD3OD) 1 H NMR chart, the data showed: 8.79 (d, J = 5.04 Hz, 2H), 7.52 (dd, J = 5.04, 4.64 Hz, 2H), 2.87 (s, 6H), 1.69 (s, 6H) ppm.

[0020] Figure 2 The BODIPY sodium pyridine disulfonate fluorescent probe in Example 1 was obtained using a Bruker Avance nuclear magnetic resonance spectrometer (100 MHz, MD3OD) 13C NMR chart, data showed: δ 157.79, 151.53, 146.23, 141.41, 136.13, 131.61, 125.71, 125.56, 14.89, 13.70 ppm.

[0021] Figure 3 The BODIPY sodium pyridine disulfonate fluorescent probe in Example 1 was obtained using a Bruker Avance nuclear magnetic resonance spectrometer (376 MHz, MD3OD) 19 F NMR chart, data show: δ-76.90ppm.

[0022] Figure 4 The BODIPY sodium pyridine disulfonate fluorescent probe in Example 1 was detected by Tensor-27 Fourier transform infrared spectrometer (resolution 2 cm -1 , spectral range 4000-400cm -1 ) obtained, the data showed: 3318(s),2972(w),1642(m),1537(m),1227(m),1184(m),1028(m),822(w),775(w).

[0023] Figure 5 The UV-visible absorption spectrum of the BODIPY sodium pyridine disulfonate fluorescent probe measured by a UV spectrophotometer (Perkin Elmer E35) in Example 2 and the excitation and emission spectra of the BODIPY sodium pyridine disulfonate fluorescent probe measured by a fluorescence spectrometer (Horiba FluoroMax-4) are shown.

[0024] Figure 6 The absorption spectrum and Beer-Lambert plot of the BODIPY sodium pyridine disulfonate fluorescent probe at concentrations ranging from 4.31 to 10.0 μM were measured using an ultraviolet spectrophotometer (Perkin Elmer E35) in Example 2.

[0025] Figure 7 The UV-visible absorption spectrum of 10.0 μM BODIPY sodium pyridine disulfonate fluorescent probe in H2O / DMSO (99:1) at pH 6.59 to 1.96 was measured by using a UV spectrophotometer (Perkin Elmer E35) in Example 2. Figure 7 The insets are photographs of BODIPY sodium pyridine disulfonate fluorescent probe solutions at pH 6.59 and 1.96, respectively, recorded under normal laboratory lighting.

[0026] Figure 8The fluorescence emission spectrum of 10.0 μM BODIPY sodium pyridine disulfonate fluorescent probe in H2O / DMSO (99:1) at pH 6.59 to 1.96 was measured using a fluorescence spectrometer (Horiba FluoroMax-4) in Example 2. Figure 8 The insets are photos of BODIPY sodium pyridine disulfonate fluorescent probe solutions at pH 6.59 and 1.96, respectively, recorded under 365 nm UV light.

[0027] Fig. 9 This is a graph showing the relationship between the fluorescence intensity ratio and pH calculated in Example 2 for 10.0 μM BODIPY sodium pyridine disulfonate fluorescent probe in H2O / DMSO (99:1) with a pH ranging from 6.59 to 1.96.

[0028] Fig.10 In Example 2, density functional theory (DFT) was used to calculate BODIPY(SO3Na)2, H + -BODIPY(SO3Na)2, BODIPY(SO3H)2 and H + -LUMO and HOMO orbital distribution and DFT optimized structure of BODIPY(SO3H)2.

[0029] Fig.11 In Example 3, when pH = 6.59, 10.0 μM BODIPY sodium pyridine disulfonate fluorescent probe was mixed with 100.0 μM of the following cations: Fe 2+ 、Na + 、Cd 2+ , Li + 、Ag + 、Ni 2+ Mg 2+ , Ba 2+ , Cu 2+ , Mn 2+ 、Zn 2+ , K + NH4 + , Ca 2+ 、Co 2+ , Hg 2+ Cr 3+ 、Al 3+ or Fe 3+ The samples were mixed in 99:1 (v / v) H2O-DMSO solution and the fluorescence emission spectra were measured.

[0030] Fig.12 In Example 3, when pH = 4.32, 10.0 μM BODIPY sodium pyridine disulfonate fluorescent probe was mixed with 100.0 μM of the following cations: Fe 2+ 、Na +、Cd 2+ , Li + 、Ag + 、Ni 2+ Mg 2+ , Ba 2+ , Cu 2+ , Mn 2+ 、Zn 2+ , K + NH4 + , Ca 2+ 、Co 2+ , Hg 2+ Cr 3+ 、Al 3+ or Fe 3+ The samples were mixed in 99:1 (v / v) H2O-DMSO solution and the fluorescence emission spectra were measured.

[0031] Fig.13 In Example 3, at pH 6.59, a series of different concentrations of Fe were added to 10 μM BODIPY sodium pyridine disulfonate fluorescent probe. 3+ , and the UV-visible absorption and Fe 3+ The relationship between concentration, Fig.13 The insets are recorded under normal laboratory light in BODIPY sodium pyridine disulfonate fluorescent probe solution at pH 6.59 without and with Fe 3+ Photos.

[0032] Fig.14 In Example 3, at pH 6.59, a series of different concentrations of Fe were added to 10 μM BODIPY sodium pyridine disulfonate fluorescent probe. 3+ , excitation wavelength 350nm, 475-600nm range, measure absorption and Fe 3+ The relationship between concentration, Fig.14 The inset is recorded under 365 nm UV light at pH 6.59 in BODIPY sodium pyridine disulfonate fluorescent probe solution without and with Fe 3+ Photos.

[0033] Fig.15 In Example 3, at pH 4.32, a series of different concentrations of Fe 3+ , and the UV absorption and Fe 3+ The relationship between concentration Fig.15 The insets are recorded under normal laboratory light in BODIPY sodium pyridine disulfonate fluorescent probe solution at pH 4.32 without and with Fe 3+ Photos.

[0034] Fig.16 In Example 3, at pH 4.32, a series of different concentrations of Fe 3+ , excitation wavelength 350nm, fluorescence spectra were measured in the range of 475-600nm; and recorded under 365nm UV light, BODIPY sodium pyridine disulfonate fluorescent probe solution without and with Fe at pH 4.32 3+ The results of the test are attached. Fig.16 Illustration.

[0035] Fig.17 In Example 4, at pH = 6.59, 100 μM of the other 18 cations (Fe 2+ ,Al 3+ ,Cr 3+ ,Hg 2+ ,Co 2+ ,Ca 2+ ,NH4 + ,K + ,Zn 2+ ,Mn 2+ ,Cu 2+ ,Ba 2+ Mg 2+ ,Ni 2+ ,Ag + ,Li + ,Cd 2+ and Na + ), followed by the addition of 50 or 100 μM Fe 3+ , to determine its selectivity.

[0036] Fig.18 In Example 4, at pH = 4.32, 100 μM of the other 18 cations (Fe 2+ ,Al 3+ ,Cr 3+ ,Hg 2+ ,Co 2+ ,Ca 2+ ,NH4 + ,K + ,Zn 2+ ,Mn 2+ ,Cu 2+ ,Ba 2+ Mg 2+ ,Ni 2+ ,Ag + ,Li+ ,Cd 2+ and Na + ), followed by the addition of 50 or 100 μM Fe 3+ , to determine its selectivity.

[0037] Fig.19 In Example 5, at pH 6.59, BODIPY(SO3Na)2, BODIPY(SO3Na)2 / Fe 3+ (50.0 μM) and BODIPY(SO3Na)2 / Fe 3+ Time-resolved fluorescence decay experiment of H2O / DMSO (99:1) solution (100.0μM) and the decay curve obtained.

[0038] Fig. 20 In Example 5, at pH 4.32, BODIPY(SO3Na)2, BODIPY(SO3Na)2 / Fe 3+ (50.0 μM) and BODIPY(SO3Na)2 / Fe 3+ (100.0μM) time-resolved fluorescence decay experiment and the decay curve obtained.

[0039] Fig.21 In Example 5, 100.0 μM CO3 was added to a 10 μM BODIPY(SO3Na)2 solution in H2O / DMSO (99:1) at pH 6.59. 2- ,SCN - ,Ac - ,S 2- ,CrO4 2- ,NO3 - ,F - ,H2PO4 - ,NO2 - ,S2O4 2- ,SO4 2- and HCO3 - anions and measure the resulting fluorescence spectra.

[0040] Fig. 22 In Example 5, 100.0 μM CO3 was added to a 10 μM BODIPY(SO3Na)2 solution in H2O / DMSO (99:1) at pH 4.32. 2- ,SCN - ,Ac - ,S 2- ,CrO4 2-,NO3 - ,F - ,H2PO4 - ,NO2 - ,S2O4 2- ,SO4 2- and HCO3 - anions and measure the resulting fluorescence spectra.

[0041] Fig.23 In Example 5, 100 μM fructose, ascorbic acid, gallic acid, isonicotinic acid and citric acid were added to a 10 μM BODIPY(SO 3 Na) 2 solution in H 2 O / DMSO (99:1) at pH 6.59, and the resulting fluorescence spectrum was measured.

[0042] Fig.24 In Example 5, 100 μM fructose, ascorbic acid, gallic acid, isonicotinic acid and citric acid were added to a 10 μM BODIPY(SO 3 Na) 2 solution in H 2 O / DMSO (99:1) at pH 4.32, and the resulting fluorescence spectrum was measured.

[0043] Fig.25 In Example 6, Fe is added 3+ Before and after, the pH value was 6.59. The Fe complexes produced during the titration were calculated using density functional theory (DFT) to calculate the LUMO and HOMO orbital distributions and DFT optimal structures of BODIPY(SO3Na)2, [(SO3Na)BODIPY(SO3)]2FeCl2 and [(SO3Na)BODIPY(SO3)]FeCl4.

[0044] Fig.26 In Example 6, Fe 3+ Before and after, pH value was 4.32. The Fe complex produced during the titration was calculated using density functional theory (DFT). + -BODIPY(SO3Na)2,

[0045] [(SO3Na)-H + -BODIPY(SO3)]FeCl4 and [(SO3Na)-H + -BODIPY(SO3)]2FeCl2 LUMO and HOMO orbital distribution and DFT optimal structure. DETAILED DESCRIPTION

[0046] The specific implementation of the present invention is further described below in conjunction with the accompanying drawings and embodiments. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention.

[0047] Example 1

[0048] S1: Prepare BODIPY-PY, introduce pyridine into the middle position of fluoroboranedipyrrole to obtain BODIPY-PY.

[0049] At room temperature, pyridine-4-carboxaldehyde (0.535 mg, 5 mmol) was dissolved in 150 mL of anhydrous CH2Cl2, and 2,4-dimethyl-1H-pyrrole (1.125 mL, 10.5 mmol) was added. Pure trifluoroacetic acid (TFA) (50 μL) was added dropwise to the above mixture as a catalyst. Stir for 5 h under N2 atmosphere and react at room temperature in the dark. Thin layer chromatography confirmed that pyridine-4-carboxaldehyde had reacted completely, and then 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ) (1.1588 g, 5 mmol, dissolved in 15 mL of benzene) was slowly added dropwise and stirred at room temperature for 2 h. Under ice bath conditions, TFA (50 μL) was added and stirred for 5 min, and then boron trifluoride etherate (5 mL) was slowly added dropwise at room temperature and stirred for 1.5 h. The reaction mixture was separated by liquid extraction and the organic layer was evaporated.

[0050] S2: In an ice NaCl bath, keep the temperature at about -20°C under N2 atmosphere, and drop 3.5 times the equivalent of fresh chlorosulfonic acid dissolved in 4mL of anhydrous dichloromethane into a solution of BODIPY-PY (0.1370g, 0.421mmol) dissolved in 2mL of anhydrous dichloromethane for 10 minutes. After the chlorosulfonic acid solution is added dropwise, remove the cooling bath, return the reaction mixture to room temperature, and stir for another 6h. Collect by filtration and dissolve in saturated sodium bicarbonate aqueous solution (20mL). Then, evaporate to dryness and reprecipitate in saturated saline to obtain a crude product. BODIPY(SO3Na)2 is obtained by silica gel rapid column chromatography.

[0051] Example 2

[0052] The optical properties and pH response of the BODIPY sodium pyridine disulfonate fluorescent probe prepared in Example 1 were investigated, including the following steps:

[0053] T1: Take the BODIPY sodium pyridine disulfonate fluorescent probe of Example 1, use a UV spectrophotometer (PerkinElmer E35) to measure its UV-visible absorption spectrum, and use a fluorescence spectrometer (Horiba FluoroMax-4) to measure its excitation and emission spectra. The maximum absorption peak is at 500nm, and the optimal excitation and emission spectra reach the maximum values ​​at 350 and 511nm respectively. The test results are shown in the attached Figure 5 .

[0054] T2: Take the BODIPY sodium pyridine disulfonate fluorescent probe of Example 1, and use a UV spectrophotometer (PerkinElmer E35) to measure the absorption spectrum and Beer-Lambert diagram of the BODIPY sodium pyridine disulfonate fluorescent probe at concentrations ranging from 4.31 to 10.0 μM. The test results are shown in the attached Figure 6 .

[0055] Attached Figure 6 The data showed that the BODIPY sodium pyridine disulfonate fluorescent probe had a high molar absorption coefficient, which was calculated to be 4.6×10 4 M -1 cm -1 .

[0056] T3: Take the BODIPY sodium pyridine disulfonate fluorescent probe of Example 1, and use a UV spectrophotometer (PerkinElmer E35) and a fluorescence spectrometer (Horiba FluoroMax-4) to measure the UV-visible absorption spectrum and fluorescence emission spectrum of 10.0 μM BODIPY sodium pyridine disulfonate fluorescent probe in H2O / DMSO (99:1) with a pH ranging from 6.59 to 1.96. Photographs of the BODIPY sodium pyridine disulfonate fluorescent probe solutions with pH values ​​of 6.59 and 1.59 under normal laboratory light and 365 nm UV light are recorded. The test results are shown in the attached Figure 7 and 8 .

[0057] Attached Figure 7 The data showed that when the pH value of the probe solution decreased from 6.59 to 1.96, the original absorption peaks at 500 and 329 nm weakened, an obvious absorption peak appeared at 546 nm, and an obvious isochromatic point appeared at 527 nm, indicating that sodium disulfonate reacted with H + The combination of is the only reaction in the acidic system. Figure 7 The inset shows that the decreasing change in pH from 6.59 to 1.96 also results in a distinct color change from yellow-green to light pink, which can be distinguished by the naked eye.

[0058] Attached Figure 8 The data showed that the BODIPY sodium pyridine disulfonate fluorescent probe exhibited good pH-dependent fluorescence decay. The fluorescence intensity at 513 nm gradually decreased in the pH range of 6.59-1.96, and the pK a is about 4.15, indicating that the BODIPY sodium pyridine disulfonate fluorescent probe is sensitive to pH.

[0059] Attached Fig. 9 The data show that the fluorescence intensity ratio F pH / F 6.59It increases with the increase of pH value and shows a good linear relationship in the pH range of 3.53-4.77. The linear equation is y=0.43x-1.25(R 2 =0.998).

[0060] T4: DFT calculations were performed on the BODIPY sodium pyridine disulfonate fluorescent probe and its three possible protonated forms at the B3LYP / 6-31G(d) level. The calculation results are shown in the attached Fig.10 .

[0061] Attached Fig.10 The data show that BODIPY(SO3Na)2 and H + -BODIPY(SO3Na)2 has a much higher energy gap than BODIPY(SO3H)2 and H + -BODIPY(SO3H)2, indicating that the first two have stronger metal ion binding ability; the higher stability and lower reactivity caused by the increased energy gap will limit the + -Further application of BODIPY(SO3H)2 in coordination with metal ions.

[0062] Example 3

[0063] The photophysical properties of the BODIPY sodium pyridinedisulfonate fluorescent probe prepared in Example 1 for iron ion sensing were investigated.

[0064] W1: When pH = 6.59, 10.0 μM BODIPY sodium pyridine disulfonate fluorescent probe was mixed with 100.0 μM of the following cations: Fe 2+ 、Na + 、Cd 2+ , Li + 、Ag + 、Ni 2+ Mg 2+ , Ba 2+ , Cu 2+ , Mn 2+ 、Zn 2+ , K + NH4 + , Ca 2+ 、Co 2+ , Hg 2+ Cr 3+ 、Al 3+ , and Fe 3+ Mix in 99:1 (v / v) H2O-DMSO solution and measure the fluorescence emission spectrum. The results are shown in the attached Fig.11 .

[0065] Attached Fig.11The data show that at pH 6.59, Fe 3+ ions have the highest selectivity, adding 5 to 10 equivalents of Fe 3+ After that, the quenching efficiency of the initial fluorescence intensity was in the range of 52%-73%. 2+ In addition, other metal ions had no obvious quenching, and their quenching efficiency was 26% of the initial fluorescence intensity.

[0066] W2: When pH = 4.32, 10.0 μM BODIPY sodium pyridine disulfonate fluorescent probe was mixed with 100.0 μM of the following cations: Fe 2+ 、Na + 、Cd 2+ , Li + 、Ag + 、Ni 2+ Mg 2+ , Ba 2+ , Cu 2+ , Mn 2+ 、Zn 2+ , K + NH4 + , Ca 2+ 、Co 2+ , Hg 2+ Cr 3+ 、Al 3+ or Fe 3+ Mix in 99:1 (v / v) H2O-DMSO solution and measure the fluorescence emission spectrum. The results are shown in the attached Fig.12 .

[0067] Attached Fig.12 The data show that at pH 4.32, the addition of Fe 3+ The addition of 5 and 10 equivalents of Fe 3+ After that, the initial fluorescence intensity was quenched by 48% and 64%, respectively.

[0068] Attached Fig.11 and 12 The data showed that the BODIPY sodium pyridine disulfonate fluorescent probe was effective for Fe 3+ Ions have high selectivity and specificity.

[0069] W3: At pH 6.59, a series of different concentrations of Fe were added to 10.0 μM BODIPY sodium pyridine disulfonate fluorescent probe. 3+ , and the UV-visible absorption and Fe 3+The relationship between the concentration of Fe and BODIPY sodium pyridine disulfonate fluorescent probe solution without and with Fe at pH 6.59 was recorded under normal laboratory light. 3+ The results of the test are attached. Fig.13 .

[0070] Attached Fig.13 The data showed that increasing Fe 3+ At doses of 100 ng / mL, the maximum absorption continuously decreases by ∼6 nm and is red-shifted, accompanied by a distinct color change from yellow-green to mango yellow observed with the naked eye.

[0071] W4: At pH 6.59, a series of different concentrations of Fe were added to 10.0 μM BODIPY sodium pyridine disulfonate fluorescent probe. 3+ , excitation wavelength 350nm, within the range of 475-600nm, the fluorescence emission and Fe 3+ The relationship between the concentration of Fe and BODIPY sodium pyridine disulfonate fluorescent probe solution was recorded under 365 nm UV light at pH 6.59 without and with Fe 3+ The results of the measurement can be found in Fig.14 .

[0072] Attached Fig.14 The data show that 0.1 and 20 equivalents of Fe 3+ The ions produced a significant quenching effect on the emission intensity of the initial fluorescence, with quenching efficiencies of 12.0% and 86.6%, respectively. When observed with the naked eye under a 365nm ultraviolet lamp, the color changed from bright green to colorless, indicating that the fluorescence was completely quenched.

[0073] W5: At pH 4.32, a series of different concentrations of Fe were added to 10.0 μM BODIPY sodium pyridine disulfonate fluorescent probe. 3+ , and the UV absorption and Fe 3+ The relationship between the concentration and the results are shown in the attached Fig.15 ; Under normal laboratory light, BODIPY sodium pyridine disulfonate fluorescent probe solution at pH 4.32 without and with Fe 3+ See attached for photos Fig.15 Illustration.

[0074] Attached Fig.15 The data showed that increasing Fe 3+ The maximum absorption continued to decrease with a red shift of 8 nm, accompanied by a color change from clay green to light brown observed by the naked eye.

[0075] W6: At pH 4.32, a series of different concentrations of Fe were added to 10.0 μM BODIPY sodium pyridine disulfonate fluorescent probe. 3+, excitation wavelength 350nm, within the range of 475-600nm, the fluorescence emission and Fe 3+ The relationship between the concentration of Fe and BODIPY sodium pyridine disulfonate fluorescent probe solution was recorded under 365 nm UV light at pH 4.32. 3+ The measurement results are shown in the attached Fig.16 .

[0076] Attached Fig.16 The data show that when 0.1 and 20 equivalents of Fe 3+ ions, the emission intensity decreased by 9.2% and 81.3% of the initial fluorescence intensity, respectively. The inset shows that 3+ After addition, the solution color changed from bright green to colorless when observed with a handheld UV lamp, as expected.

[0077] Example 4

[0078] In the BODIPY sodium pyridine disulfonate fluorescent probe prepared in Example 1, Fe 3+ Compete with other metal ions for coordination.

[0079] L1: At pH = 6.59, 100 μM of the other 18 cations (Fe 2+ ,Al 3+ ,Cr 3+ ,Hg 2+ ,Co 2+ ,Ca 2+ ,NH4 + ,K + ,Zn 2+ ,Mn 2+ ,Cu 2+ ,Ba 2+ Mg 2+ ,Ni 2+ ,Ag + ,Li + ,Cd 2+ and Na + ), followed by the addition of 50 or 100 μM Fe 3+ , measure its fluorescence spectrum, its selective fluorescence spectrum is shown in the attached Fig.17 .

[0080] Attached Fig.17 The data show that at pH 6.59, except for Fe 2+ Except for weak quenching, the addition of other metal ions did not cause significant interference. When 5 equivalents of Fe 3+When Fe was added to BODIPY(SO3Na)2, the fluorescence intensity was significantly reduced (the quenching efficiency was 49-55%). 3+ (quenching efficiency is 52%). In addition, 10 equivalents of Fe 3+ It can induce 68-73% fluorescence quenching, which is comparable to Fe 3+ The quenching efficiency (73%) was comparable when BODIPY(SO3Na)2 was added.

[0081] L2: At pH = 4.32, 100 μM of the other 18 cations (Fe 2+ ,Al 3+ ,Cr 3+ ,Hg 2+ ,Co 2+ ,Ca 2+ ,NH4 + ,K + ,Zn 2+ ,Mn 2+ ,Cu 2+ ,Ba 2+ Mg 2+ ,Ni 2+ ,Ag + ,Li + ,Cd 2+ and Na + ), followed by the addition of 50 or 100 μM Fe 3+ , measure its fluorescence spectrum, its selective fluorescence spectrum is shown in the attached Fig.18 .

[0082] Attached Fig.18 The data show that at pH 4.32, metal cations including Fe 2+ Cr 3+ 、Al 3+ and Hg 2+ The effect on the fluorescence spectrum of BODIPY(SO3Na)2 is negligible. 3+ , Hg 2+ 、Co 2+ NH4 + , K + and Cd 2+ In addition, 5 and 10 equivalents of Fe 3+ Compared with adding Fe alone to BODIPY(SO3Na)2 3+ The degree of quenching is similar.

[0083] Attached Fig.17 and attached Fig.18The data together indicate that BODIPY(SO3Na)2 is active against Fe at pH 6.59 even in the presence of competing ions. 3+ With the best selectivity.

[0084] Example 5

[0085] Study on the BODIPY sodium pyridine disulfonate fluorescent probe prepared in Example 1 for detecting Fe 3+ The mechanism and Fe 3+ Quenching effect on BODIPY sodium pyridinedisulfonate fluorescent probe.

[0086] M1: BODIPY(SO3Na)2, BODIPY(SO3Na)2 / Fe at pH 6.59 using a Horiba Jobin-Yvon FL3 instrument 3+ (50.0 μM) and BODIPY(SO3Na)2 / Fe 3+ The time-resolved fluorescence decay experiment of H2O / DMSO (99:1) solution (100.0 μM) was performed. The decay curve obtained is shown in the attached figure. Fig.19 ; BODIPY(SO3Na)2, BODIPY(SO3Na)2 / Fe at pH 4.32 using a Horiba Jobin-Yvon FL3 instrument 3+ (50.0 μM) and BODIPY(SO3Na)2 / Fe 3+ (100.0 μM) time-resolved fluorescence decay experiment, the decay curve obtained is shown in the attached Fig. 20 .

[0087] Attached Fig.19 and attached Fig. 20 The data showed that the fluorescence lifetimes of BODIPY(SO3Na)2 at pH 6.59 and 4.32 were 1.61 and 1.53 ns, respectively. 3+ , the fluorescence lifetimes of BODIPY(SO3Na)2 at pH 6.59 were 1.54 ns and 1.53 ns, respectively, which are actually the same as the fluorescence lifetime of free BODIPY(SO3Na)2. These results indicate that the fluorescence quenching of BODIPY(SO3Na)2 at pH 6.59 is static quenching. At a concentration of 50.0 or 100.0 μM, the lifetimes of BODIPY(SO3Na)2 at pH 4.32 were 1.49 and 1.48 ns, respectively, which also indicates that the addition of Fe 3+ The small change in fluorescence lifetime mentioned above may be due to the formation of complexes in the ground state.

[0088] M2: According to the attached Fig.19and attached Fig. 20 The decay curves shown were determined using single photon counting technology to determine the fluorescence lifetime (τ), which was calculated based on a double exponential fit. The calculation results are shown in Table 1.

[0089] Table 1

[0090]

[0091] The data in Table 1 show that the static quenching τ0 / τ ratio is 1.05, indicating static quenching from pH 6.59 to 4.32.

[0092] M3: At pH 6.59, 100.0 μM CO3 was added to a 10 μM BODIPY(SO3Na)2 solution in H2O / DMSO (99:1). 2- ,SCN - ,Ac - ,S 2- ,CrO4 2- ,NO3 - ,F - ,H2PO4 - ,NO2 - ,S2O4 2- ,SO4 2- and HCO3 - anion, and then 50 μM or 100 μM Fe 3+ , and measure its fluorescence spectrum. Its fluorescence spectrum is shown in the attached Fig.21 .

[0093] Attached Fig.21 The data showed that at pH 6.59, the addition of anions had no significant effect on BODIPY(SO3Na)2.

[0094] M4: At pH 4.32, 100.0 μM CO3 was added to a 10 μM BODIPY(SO3Na)2 solution in H2O / DMSO (99:1). 2- ,SCN - ,Ac - ,S 2- ,CrO4 2- ,NO3 - ,F - ,H2PO4 - ,NO2 - ,S2O4 2- ,SO4 2- and HCO3 - Then 50 μM or 100 μM Fe 3+ , and measure their fluorescence spectra. The fluorescence spectra are shown in the attached Fig. 22.

[0095] Attached Fig. 22 The data show that due to the presence of the above anions, at pH 4.32, except for Ac - 、CrO4 2- 、CO3 2- , S 2- and HCO3 - In addition, the fluorescence intensity of BODIPY(SO3Na)2 decreased slightly.

[0096] M5: At pH 6.59, 100 μM fructose, ascorbic acid, gallic acid, isonicotinic acid, and citric acid were added to a 10 μM BODIPY(SO3Na)2 solution in H2O / DMSO (99:1), and then 50 μM or 100 μM Fe 3+ , and measure its fluorescence spectrum. Its fluorescence spectrum is shown in the attached Fig.23 .

[0097] Attached Fig.23 The data showed that the fluorescence intensity of BODIPY(SO3Na)2 decreased slightly after the addition of neutral molecule fructose, and ascorbic acid and gallic acid were both moderately quenched at this pH.

[0098] M6: At pH 4.32, 100.0 μM fructose, ascorbic acid, gallic acid, isonicotinic acid, and citric acid were added to a 10 μM BODIPY(SO3Na)2 solution in H2O / DMSO (99:1), and then 50 μM or 100 μM Fe 3+ , and measure their fluorescence spectra. The fluorescence spectra are shown in the attached Fig.24 .

[0099] Attached Fig.24 The data showed that citric acid induced dominant quenching at pH 4.32. Due to the low pKa value of citric acid (2.93), it is estimated that the protonation of BODIPY(SO3Na)2 was enhanced, resulting in significant quenching. At pH 4.32, the quenching rate of isonicotinic acid was lower than that of ascorbic acid and gallic acid. The pyridine in isonicotinic acid is believed to react with H + -Pyridine in BODIPY(SO3Na)2 exchanges protons and reduces the protonation of BODIPY(SO3Na)2, thereby restoring the fluorescence intensity.

[0100] Example 6

[0101] The coordination chemical mechanism of the BODIPY sodium pyridinedisulfonate fluorescent probe prepared in Example 1 was investigated using DFT calculations.

[0102] Y1: Add Fe 3+Density functional theory (DFT) was used to calculate the electronic properties of the chemical structures of BODIPY(SO3Na)2, [(SO3Na)BODIPY(SO3)]2FeCl2, and [(SO3Na)BODIPY(SO3)]FeCl4. The calculation results are shown in the Appendix. Fig.25 ; Density functional theory (DFT) was used to calculate H + -BODIPY(SO3Na)2,[(SO3Na)-H + -BODIPY(SO3)]FeCl4 and [(SO3Na)-H + -BODIPY(SO3)]2FeCl2 chemical structure electronic properties, the calculation results are shown in the attached Fig.26 .

[0103] Attached Fig.25 The data indicate that BODIPY(SO3Na)2 can produce more efficient electronic coupling with iron(III), which is consistent with the observed blue shift in the ultraviolet absorption spectrum, reflecting that BODIPY(SO3Na)2 will exhibit a unimolecular coordination mode with iron(III).

[0104] Attached Fig.26 The data show that H + -BODIPY(SO3Na)2 and Fe(III) can generate effective electronic coupling, and the decrease of energy gap is associated with the corresponding blue shift, showing the H + The stoichiometric ratio of -BODIPY(SO3Na)2 to Fe(III) is 1:1.

[0105] The above data show that BODIPY(SO3Na)2 has a significant effect on Fe 3+ The optimum pH for detection is 6.59.

[0106] Example 7

[0107] Study on the detection of Fe by BODIPY sodium pyridine disulfonate fluorescent probe prepared in Example 1 3+ reliability and practicality.

[0108] Z1: First, the water sample was pretreated using the reported method and its pH value was measured to be 6.47. Then a recovery experiment was conducted and the results are shown in Table 2.

[0109] Table 2

[0110]

[0111] The data in Table 2 show that the addition of Fe to the aqueous dispersion of BODIPY(SO3Na)23+ After that, Fe 3+ The results were in good agreement with the standard addition, with recoveries ranging from 100.5% to 102.4% and standard deviations within 2.14%, which successfully verified the detection of Fe by BODIPY(SO3Na)2 in real water samples. 3+ potential and feasibility.

[0112] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. Preparation of a BODIPY sodium pyridine disulfonate fluorescent probe that responds to pH changes and detects Fe at different pH levels 3+ The use of the reagent is characterized in that The structural formula of the BODIPY sodium pyridine disulfonate fluorescent probe is shown below: ； The BODIPY sodium pyridine disulfonate fluorescent probe responds to pH changes in the pH range of 1.96–6.59; The BODIPY sodium pyridine disulfonate fluorescent probe detects iron ions when the pH is 6.59 or 4.32.

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