Preparation method and application of cadmium-based fluorescent probe material

Abstract

The application discloses a preparation method and application of a cadmium-based fluorescent probe material. The probe compound is obtained by using inorganic cadmium salt and o-phenanthroline as reactants through water bath reaction, and has a chemical formula of [Cd(phen)2(NO3)2], and cell parameters of alpha=90.00°, beta=105.939(1)° and gamma=90.00°. The probe compound has high fluorescence emission efficiency and fluorescence stability, can produce fluorescence quenching effect on Fe 3+ , Co 2+ and Cr2O7 2‑ of different concentration ranges, and can produce fluorescence enhancement effect on SCN ‑ , Br ‑ and I ‑ of different concentration ranges. The probe compound has simple synthesis process, cheap and easily obtained raw materials, good stability, high yield and high purity, can produce specific response to Fe 3+ , Co 2+ , Cr2O7 2‑ , SCN ‑ , Br ‑ and I ‑ at the same time, and has good application prospect.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of fluorescent probe complexes, and particularly relates to a preparation method and application of a multifunctional fluorescent probe complex capable of simultaneously identifying Fe 3+ , Co 2+ , Cr2O7 2- , Br - , SCN - and I - in a water body. BACKGROUND

[0002] With the increasingly serious environmental pollution, it is increasingly important to monitor harmful substances in the atmosphere, water, soil and organisms. Fluorescence analysis method has attracted the attention of many scholars due to its advantages of small sample amount, fast analysis speed, high sensitivity and convenient operation. Compared with traditional luminescent materials, complex fluorescent materials have attracted much attention due to their high chemical stability of inorganic materials and high quantum yield of organic materials. A series of fluorescent probe complexes have been reported, but fluorescent probe complexes capable of simultaneously detecting multiple guests are still very few.

[0003] Iron is a trace amount of transition metal element in organisms, which participates in the composition of a variety of enzymes and immune systems in the human body, and is also the main component of hemoglobin. Insufficient or excessive iron in the body will cause many diseases and affect human health. However, if the iron content in the human body is excessive, it will cause changes in the structure of human organs, leading to diseases such as liver fibrosis, and even life-threatening in severe cases. Cobalt is also an important transition metal. When the concentration of cobalt ions in water exceeds the standard, it will cause serious health problems, such as hypotension, paralysis, diarrhea and defects, polycythemia, skin allergy and other diseases, and also cause gene mutation of living cells. Excessive concentration of Co 2+ in water will also inhibit the metabolism and growth and reproduction of microorganisms. Cr2O7 2- is an environmental non-biodegradable pollutant. Due to its strong mutagenic and carcinogenic effect, it can accumulate in organisms, causing internal organ damage and water-borne diseases. Bromine and iodine can participate in the synthesis of hormones, enzymes and type IV collagen in the human body, and iodine has a more obvious effect on the physiological function of the human body. Too little or too much will cause hyperthyroidism. Thiocyanate is one of the important components of the lactoperoxidase antioxidant system and is often used as a fresh milk preservative. Excessive intake can cause acute and chronic poisoning. Mild poisoning shows eye and upper respiratory tract irritation symptoms, and severe poisoning shows loss of consciousness, often accompanied by brain edema and respiratory failure. In particular, there is a great risk to the intelligence and nervous system development of fetuses and infants.

[0004] Currently, several traditional methods for determining the above ions have been established, such as spectrophotometry, chromatography, electrochemistry and inductively coupled plasma mass spectrometry, etc. However, these methods are usually expensive, time-consuming, or require a complex sample preparation process. In the prior art, most of the metal complexes available as fluorescent probe materials are prepared by a hydrothermal method or a solvothermal method, which requires a high-temperature and high-pressure sealed reaction system, is time-consuming, and has a large potential safety hazard. CN 111848655A discloses a preparation method and application of a three-dimensional cadmium complex fluorescent probe, which can be used to identify iron ions and carbonate ions in water bodies, and is prepared by a 100 DEG C solvothermal method, which is long in cycle (48 hours) and high in cost; CN 113354668A discloses a rare earth fluorescent probe material [Eu(ndc)(Hndc)(DMF)2] based on 1,4-naphthalene dicarboxylic acid (ndc), which can exhibit red light emission under irradiation of excitation light at 250-330 nm, and can be used to detect Pb n , Cu 2+ , Cd 2+ , and Cd 2+ . The material is prepared by a 90 DEG C-120 DEG C solvothermal method, which is still long in cycle (24-72 hours), and the rare earth is expensive in price and high in cost.

[0005] In view of the above problems, the present application is proposed. SUMMARY

[0006] The present application provides a preparation method and application of a cadmium-based fluorescent probe material, and the specific preparation method is as follows:

[0007] Step 1: mix a cadmium metal salt solution with o-phenanthroline in a mixed solution of water and methanol, and stir and react at 50-60 DEG C;

[0008] Step 2: filter the solution of step 1, and naturally volatilize or rotary evaporate the solvent of the filtrate to obtain a solid powder of Cd(phen)2(NO3)2;

[0009] Further, the substance amount ratio of the cadmium metal salt solution to o-phenanthroline is 1:1-1.2;

[0010] The reaction is carried out by water bath incubation, and the reaction time is 0.5-1 h;

[0011] The present application also discloses a cadmium-based fluorescent probe material, which has a composition of [Cd(phen)2(NO3)2], the prepared Cd complex has a space group of C2 / c and belongs to a monoclinic system;

[0012] Further, the coordination of cadmium ions is an octahedral mode, the eight coordination sites of Cd are N1, N1A, N3, N3A of the phenanthroline ligand and O1, O1A, O3, O3A from nitrate;

[0013] Further, the bond length of Cd-N1 is The bond length of Cd-N3 is The bond length of Cd-O1 is The bond length of Cd-O3 is forming an irregular dodecahedron configuration; wherein the unit cell parameters of the cadmium-based fluorescent probe material are b = 15.2574 (9), α = 90°, β = 105.939 (1) °, γ = 120°.

[0014] The cadmium-based fluorescent probe material can be used as a fluorescent probe and applied to identify Fe 3+ , Co 2+ , SCN - , Br - , I - in water.

[0015] As the above technical solutions are adopted, the beneficial effects obtained by the present application are:

[0016] The cadmium-based fluorescent probe material obtained by the present application has a simple preparation method, reliable operation, high yield, and the yield can reach 90%. At the same time, the unique irregular dodecahedron configuration structure of the material gives the cadmium-based fluorescent probe material unique advantages in the field of fluorescent probes. Under the condition of λ em = 368 nm, Fe 3+ and Co 2+ have a relatively obvious quenching effect on the fluorescence intensity of Cd(phen)2(NO3)2, which can be used as Fe 3+ and Co 2+ sensor materials; the fluorescence emission intensity of Cd(phen)2(NO3)2 at λ em = 647 nm is obviously enhanced in Br - , SCN - and I - solutions, and the intensity is 45, 42 and 23 times of the original, respectively; Cd(phen)2(NO3) can be used as a fluorescent probe to identify Fe 3+ and Co 2+ metal ions and SCN - , Br - and I - anions, and has a good application prospect for ion identification and detection of water bodies. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 Schematic diagram of crystal structure of Cd(phen)2(NO3)2;

[0018] Figure 2 Fluorescence emission spectrum of Cd(phen)2(NO3)2;

[0019] Figure 3 Fluorescence spectra of Cd(phen)2(NO3)2 in different metal cation solutions;

[0020] Figure 4 Comparison chart of luminescence intensity of Cd(phen)2(NO3)2 in different metal cation solutions;

[0021] Figure 5 Fluorescence spectra of Cd(phen)2(NO3)2 in different concentrations of Fe 3+ solution;

[0022] Figure 6 Linear fitting chart of Cd(phen)2(NO3)2 in different concentrations of Fe 3+ solution;

[0023] Figure 7 Fluorescence spectra of Cd(phen)2(NO3)2 in different concentrations of Co 2+ solution;

[0024] Figure 8 Linear fitting chart of Cd(phen)2(NO3)2 in different concentrations of Co 2+ solution;

[0025] Figure 9 Fluorescence spectra of Cd(phen)2(NO3)2 in different anion solutions;

[0026] Figure 10 Comparison chart of fluorescence intensity (λ em = 368 nm) of Cd(phen)2(NO3)2 in different anion solutions;

[0027] Figure 11 Fluorescence spectra of Cd(phen)2(NO3)2 in different concentrations of Cr2O7 2- solution;

[0028] Figure 12 Linear fitting chart of Cd(phen)2(NO3)2 in different concentrations of Cr2O7 2- solution;

[0029] Figure 13Fluorescence intensity (λ = 647 nm) of Cd(phen)2(NO3)2 in different anion solutions em = 647 nm) versus graph.

[0030] Figure 14 Infrared spectrum of Cd(phen)2(NO3)2 DETAILED DESCRIPTION

[0031] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be described in detail below with specific examples and experimental data. Obviously, the described examples are only some of the embodiments of the present application, but not all the embodiments. Based on the examples in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0032] The following is an example of a specific example.

[0033] Example 1

[0034] 0.1850 g (0.6 mmol) of Cd(NO3)2·4H2O and 0.1189 g (0.6 mmol) of o-phenanthroline were dissolved in a mixed solvent consisting of 10 mL of water and 20 mL of methanol, and reacted at 50°C under water bath conditions for 0.5 h. After the reaction was completed, the reaction solution was naturally cooled to room temperature under magnetic stirring, and then filtered. The filtrate was directly evaporated at room temperature or rotary evaporated to obtain the target product powder with a yield of 90%. High-quality single crystal samples suitable for X-ray single crystal diffraction can be obtained by slowly evaporating the filtrate at room temperature.

[0035] The obtained product was subjected to structural analysis. X-ray crystallographic analysis showed that the prepared Cd complex had a space group of C2 / c, belonged to a monoclinic system, and had a molecular structure as shown in Figure 1 The structure model is shown in Figure 2 The Cd complex contained one cadmium ion, two o-phenanthroline ligands and two nitrate ions, which can be clearly seen from Figure 1 The eight coordination sites of the Cd were occupied by N1, N1A, N3, N3A from the o-phenanthroline ligands and O1, O1A, O3, O3A from the nitrate ions, respectively. The bond length of Cd-N1 was The bond length of Cd-N3 was The bond length of Cd-O1 was The bond length of Cd-O3 was forming a distorted dodecahedron configuration. This dodecahedron coordination configuration is very rare in cadmium o-phenanthroline complexes. The crystallographic parameters of the Cd complex are shown in Table 1, and the important bond lengths and bond angles are shown in Table 2.

[0036] Table 1. Crystallographic parameters of [Cd(phen)2(NO3)2]

[0037]

[0038] a R1=∑||F o |-|F c || / ∑|F o |, b wR2=[∑w(F o 2 -F c 2 ) 2 / ∑w(F o 2 ) 2 ] 1 / 2

[0039] Table 2. Partial bond lengths and bond angles of [Cd(phen)2(NO3)2]

[0040]

[0041] Symmetric code: a) 1-x, y, 1.5-z

[0042] Example 2

[0043] Fluorescence properties of [Cd(phen)2(NO3)2]

[0044] To further verify the fluorescence properties of this product, fluorescence testing was performed using a Hitachi 850 fluorescence spectrophotometer. The fluorescence emission spectrum of [Cd(phen)2(NO3)2] is shown below. Figure 3 As shown. In λ ex Excitation by light at λ = 322.03 nm, at λ em Fluorescence emission peaks appeared at three positions: 368, 385, and 647 nm. Among them, λ... em The two relatively strong fluorescence emission peaks at 368 and 385 nm are due to the π-ray emission from the o-phenanthroline ligand. * Caused by -π charge transition, λ em The weak fluorescence emission peak at 647 nm is due to the presence of LLCT (o-phenanthroline π) in the complex. * → Caused by nitrate π charge transition.

[0045] A series of metal solutions were prepared, wherein the ion concentration in the metal solutions was 1.0 × 10⁻³ mol / L, and the metal ions in the metal solutions included Bi³⁺, Mg²⁺, Cd²⁺, Na⁺, Cr²⁺, Pb²⁺, Cu²⁺, Co²⁺, Ni²⁺, and Fe³⁺. 3 mL of the above metal solutions were taken, 1.5 mg of M powder was added, and the mixture was ultrasonically mixed until homogeneous. The fluorescence intensity was then measured.

[0046] A series of metal solutions were prepared, wherein the ion concentration in the metal solutions was 1.0 × 10⁻⁶. -3 mol / L, metal ion is Bi 3+ Mg 2+ Cd 2+ Na + Cr 2+ Pb 2+ Cu 2+ Co 2+ Ni 2+ Fe 3+ The above metal is a nitrate solution. Take 3 mL of the above metal solution, add 1.5 mg of M powder, mix it evenly by ultrasonication, and measure its fluorescence intensity.

[0047] Based on the potential luminescence properties of Cd(phen)₂(NO₃)₂, the results show that, with an excitation wavelength of 322 nm, the luminescence intensity of Cd(phen)₂(NO₃)₂ in solutions of different metal ions with the same mass concentration (0.001 mol / L) follows the order of Bi. 3+ >Mg 2 + >Cd 2+ >Na + >Cr 2+ >Pb 2+ >Cu 2+ >Co 2+ >Ni 2+ >Fe 3+ (like Figure 4 and Figure 5 (As shown). Within the emission wavelength range of 340–800 nm, the emission peak positions and shapes of Cd(phen)₂(NO₃)₂ in the above-mentioned metal ion solutions are very similar, but the luminescence intensities differ significantly, indicating that these metal ions have varying degrees of influence on the fluorescence intensity of Cd(phen)₂(NO₃)₂. A comparison reveals that within the λ... em Under the condition of 368nm, Fe 3+ and Co 2+ The fluorescence intensity of Cd(phen)₂(NO₃)₂ exhibits a significant quenching effect, indicating that Cd(phen)₂(NO₃)₂ can serve as a potential Fe²⁺ quenching agent. 3+ and Co2+ Sensor materials.

[0048] To further investigate the effect of Cd(phen)2(NO3)2 on Fe... 3+ and Co 2+ To assess the sensing sensitivity of Cd(phen)2(NO3)2 at different concentrations of Fe, we successively investigated the sensing sensitivity of Cd(phen)2(NO3)2. 3+ Co 2+ Fluorescence spectra in solution. Cd(phen)₂(NO₃)₂ was dispersed in water (0.5 mg / mL) and a suspension was obtained by ultrasonic treatment. Then, different volumes (range 0-17 μL) of Fe were added to the above suspension. 3+ Co 2+ The fluorescence emission spectrum of the solution (0.1 mol / L) was measured. With Fe... 3+ Co 2+ With increasing concentration, the fluorescence intensity of Cd(phen)2(NO3)2 gradually decreases (e.g. Figure 6 to Figure 9 (As shown). We use the Stern-Volmer (SV) formula (I0 / I=1+K) sv [M]) The quenching constants of the two ions were calculated, where I0 is the initial luminescence intensity of the sample in aqueous solution, and I is the quenching constant of the sample after the addition of Co. 2+ Ni 2+ Fe 3+ Luminescence intensity after solution treatment, K sv Let [M] be the quenching constant, and [M] be the molar concentration of the quencher. Calculations show that Fe... 3+ K sv 5.08×10 3 L / mol, the limit of detection (LOD) is 9.23 × 10⁻⁶. -3 Co 2+ K sv It is 8.33×10 3 L / mol, the limit of detection (LOD) is 6.80 × 10⁻⁶. -3 .

[0049] To further verify the fluorescence characteristics of Cd(phen)₂(NO₃)₂ for metal ions, the fluorescence spectra of Cd(phen)₂(NO₃)₂ in different anion solutions with the same mass concentration (0.001 mol / L) were measured using 322 nm as the excitation wavelength. The anion solution was SO₄²⁻. 2- F - CH3COO - Cl - H2PO4 - HSO3 - , Br - SCN- , I - , Cr2O7 2- , the potassium salt solution, the results show that the position and shape of the emission peak of Cd(phen)2(NO3)2 in the anion solution are very similar (as shown in Figure 10 ), but the luminescence intensity has obvious difference: the fluorescence emission peak intensity at λ em = 368 nm from strong to weak is SO4 2- > F - > CH3COO - > Cl - > H2PO4 - > HSO3 - > Br - > SCN - > I - > Cr2O7 2- (as shown in Figure 10 ), in which Cr2O7 2- exhibits a very obvious quenching effect. In order to explore the sensing sensitivity of Cd(phen)2(NO3)2 to Cr2O7 2- , we successively studied the fluorescence spectrum of Cd(phen)2(NO3)2 in Cr2O7 2- solution with different concentrations. Cd(phen)2(NO3)2 was dispersed in water (0.5 mg / mL), and a suspension was obtained by ultrasonic treatment. Different volumes of Cr2O7 2- ions (0.1 mol / L) were added into the above suspension respectively, and the fluorescence emission spectrum was measured. With the increase of Cr2O7 2- ion concentration, the fluorescence intensity of Cd(phen)2(NO3)2 gradually decreased (as shown in Figure 12 and Figure 13 ). The Stern-Volmer (S-V) formula (I0 / I = 1 + K sv [M]) was used to calculate the quenching constant of Cr2O7 2- ion: the K 2- of Cr2O7 sv is 9.14 x 10 3 L / mol, and the lowest detection limit LOD is 3.64 x 10 -3 .

[0050] As shown in Figure 10 and Figure 14 , the fluorescence emission intensity of Cd(phen)2(NO3)2 at λ em = 647 nm in Br - , SCN - and I -The intensity of the solution was enhanced obviously, which was 45, 42 and 23 times of the original, respectively. It showed that Cd(phen)2(NO3)2 could be used as a potential fluorescence enhanced probe to detect SCN - , Br - and I - in water.

[0051] In conclusion, Cd(phen)2(NO3)2 had good fluorescence sensitivity to Fe 3+ and Co 2+ metal ions and SCN - , Br - and I - anions, and was suitable for use as a fluorescence probe for the above metal ions and anions.

Claims

1. Use of a cadmium-based fluorescent probe material, characterized in that, The cadmium-based fluorescent probe material is prepared into a fluorescent probe and applied to identifying Fe 3+ , Co 2+ , SCN - , Br - , I - ; The cadmium-based fluorescent probe material is [Cd(phen)2(NO3)2], the complex space group of the cadmium-based fluorescent probe material is C2 / c, and the cadmium-based fluorescent probe material belongs to a monoclinic system; The specific preparation method of the cadmium-based fluorescent probe material is as follows: Step 1: uniformly mix cadmium nitrate tetrahydrate and o-phenanthroline in a mixed solution of water and methanol, and stir and react at 50-60 DEG C; Step 2: filter the solution of step 1, and naturally volatilize or rotary evaporate the solvent of the filtrate to obtain a solid powder of Cd(phen)2(NO3)2.

2. Use of a cadmium-based fluorescent probe material according to claim 1, characterized in that, The molar ratio of cadmium nitrate tetrahydrate to o-phenanthroline is 1:1-1.2; the reaction is carried out by water bath incubation, and the reaction time is 0.5-1 h.

3. Use of a cadmium-based fluorescent probe material according to claim 1, characterized in that, The coordination of cadmium ions in the [Cd(phen)2(NO3)2] is an eight-coordination mode, and the eight coordination sites of the cadmium ions are N1, N1A, N3, N3A of the o-phenanthroline ligand and O1, O1A, O3, O3A from the nitrate radical.

4. The use of a cadmium-based fluorescent probe material according to claim 1, characterized in that, In the coordination mode of the [Cd(phen)2(NO3)2], the bond length of Cd-N1 is 2.3333(1) Å, the bond length of Cd-N3 is 2.33401(1) Å, the bond length of Cd-O1 is 2.5938(1) Å, and the bond length of Cd-O3 is 2.5710(1) Å, which together form an irregular dodecahedron configuration.

5. The application of the cadmium-based fluorescent probe material according to claim 1, wherein, The unit cell parameters of the cadmium-based fluorescent probe material are a=11.6936(7) Å, b=15.2574(9), c=13.4518(8) Å, α=90°, β=105.939(1) °, and γ=120°.

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