阅读说明：本技术 一种双核镉配合物及其制备方法和应用 (Binuclear cadmium complex and preparation method and application thereof ) 是由 毛佳伟 朱敏 吴宇 徐嘉麒 田华 丁劲松 李铭 王美娜 朱海 于 2021-10-26 设计创作，主要内容包括：本发明属于合成化合物技术领域。本发明提供了一种双核镉配合物,本发明以取代苯酚和N,N-二(3-氨丙基)-2-吡啶甲胺为原料,以大配位数的铅离子为模板,进行配位缩合反应得到了铅配合物；将铅配合物和硫酸镉混合,将配合物中的铅离子置换,得到了双核镉配合物,置换出来的铅离子形成硫酸铅沉淀,便于后续的过滤分离。本发明提供的制备方法简单,核心步骤为配位缩合反应和置换反应,能高效的制备得到目标配合物。经过实验验证,本发明制备的双核镉配合物和一氧化氮能形成稳定的复合物,检测限低,可用于制备一氧化氮荧光探针产品。(The invention belongs to the technical field of synthetic compounds. The invention provides a binuclear cadmium complex, which is prepared by taking substituted phenol and N, N-bis (3-aminopropyl) -2-pyridine methylamine as raw materials and taking lead ions with large coordination numbers as a template through a coordination condensation reaction; the lead complex and cadmium sulfate are mixed, lead ions in the complex are replaced to obtain a binuclear cadmium complex, and the replaced lead ions form lead sulfate precipitates, so that subsequent filtration and separation are facilitated. The preparation method provided by the invention is simple, the core steps are coordination condensation reaction and replacement reaction, and the target complex can be efficiently prepared. Experiments prove that the binuclear cadmium complex prepared by the invention and nitric oxide can form a stable complex, has low detection limit, and can be used for preparing a nitric oxide fluorescent probe product.)

1. A binuclear cadmium complex is characterized by having the following structure:

and R is methyl, methoxy, F, Cl or Br.

2. The method for preparing the dinuclear cadmium complex according to claim 1, comprising the steps of:

(1) mixing substituted phenol, lead acetate and absolute ethyl alcohol to obtain a mixed solution;

(2) mixing the mixed solution with an absolute ethyl alcohol solution of N, N-bis (3-aminopropyl) -2-pyridine methylamine, and then carrying out coordination condensation reaction to obtain a lead complex;

(3) mixing a lead complex and an anhydrous methanol solution of cadmium sulfate, and then carrying out a displacement reaction to obtain the binuclear cadmium complex;

the substituted phenol is 2, 6-diformyl-4-methylphenol, 2, 6-diformyl-4-methoxyphenol, 2, 6-diformyl-4-fluorophenol, 2, 6-diformyl-4-chlorophenol or 2, 6-diformyl-4-bromophenol.

3. The method according to claim 2, wherein the molar ratio of the substituted phenol to the lead acetate in the step (1) is 0.4 to 0.6: 0.4 to 0.6;

the molar volume ratio of the substituted phenol to the absolute ethyl alcohol is 0.4-0.6 mmol: 10-20 mL.

4. The method according to claim 3, wherein the mixing in step (1) is performed by stirring at a rotation speed of 200 to 400rpm for 1.8 to 2.2 hours.

5. The method according to any one of claims 2 to 4, wherein the molar ratio of N, N-bis (3-aminopropyl) -2-pyridinemethylamine in step (2) to the substituted phenol in step (1) is from 0.4 to 0.6: 0.4 to 0.6;

the molar volume ratio of the anhydrous ethanol solution of the N, N-bis (3-aminopropyl) -2-pyridinemethylamine to the anhydrous ethanol solution of the N, N-bis (3-aminopropyl) -2-pyridinemethylamine is 0.4-0.6 mmol: 8-12 mL.

6. The method according to claim 5, wherein the mixing in the step (2) is carried out by adding dropwise an absolute ethanol solution of N, N-bis (3-aminopropyl) -2-pyridinemethylamine to the mixed solution;

the dropping speed is 2-4 drops/second.

7. The method according to claim 2 or 6, wherein the time of the coordination condensation reaction in the step (2) is 2.5 to 3.5 hours.

8. The method according to claim 7, wherein the molar ratio of the cadmium sulfate in the step (3) to the substituted phenol in the step (1) is 0.15 to 0.184: 0.4 to 0.6;

the molar volume ratio of the cadmium sulfate to the anhydrous methanol solution of the cadmium sulfate is 0.15-0.184 mmol: 10-20 mL.

9. The production method according to claim 2, 3, 4, 6 or 8, wherein the mixing in the step (3) is carried out by dropping an anhydrous methanol solution of cadmium sulfate into the lead complex;

the dropping speed is 2-4 drops/second;

the time of the replacement reaction is 3.5-4.5 h.

10. The use of the dinuclear cadmium complex of claim 1 in the preparation of nitric oxide fluorescent probe products.

Technical Field

The invention relates to the technical field of synthetic compounds, in particular to a binuclear cadmium complex and a preparation method and application thereof.

Background

Nitric oxide is widely distributed in various tissues in the body, particularly in nerve tissues, and is a novel biological messenger molecule. Nitric oxide is an extremely unstable biological free radical, has a small molecule and a simple structure, is gas at normal temperature, is slightly soluble in water, has fat solubility, and can quickly permeate a biological membrane for diffusion. The biological half-life period of the nitric oxide is only 3-5 s, the generation of the nitric oxide depends on nitric oxide synthetase, and the nitric oxide has very important biological effects on the aspects of cardiovascular and cerebrovascular regulation, nerve regulation, immune regulation and the like, so that the nitric oxide is generally regarded by people. Nitric oxide in air can be quickly converted into nitrogen dioxide to generate stimulation, and the generated nitrogen oxide can cause respiratory tract stimulation and damage the respiratory tract; the human body is in an excessive nitrogen oxide environment, symptoms such as chest distress, respiratory distress, cyanosis and the like can appear, and the high concentration of nitric oxide can cause methemoglobinemia. In the examination, the detection of nitric oxide is an important detection item, but the detection result may be biased due to its short half-life and fast diffusion characteristics. Therefore, how to complete the detection of nitric oxide becomes a hot issue in current research.

Disclosure of Invention

The invention aims to overcome the problems in the prior art and provide a binuclear cadmium complex and a preparation method and application thereof.

In order to achieve the above object, the present invention provides the following technical solutions:

the invention provides a binuclear cadmium complex which has the following structure:

and R is methyl, methoxy, F, Cl or Br.

The invention provides a preparation method of the binuclear cadmium complex, which comprises the following steps:

(1) mixing substituted phenol, lead acetate and absolute ethyl alcohol to obtain a mixed solution;

(2) mixing the mixed solution with an absolute ethyl alcohol solution of N, N-bis (3-aminopropyl) -2-pyridine methylamine, and then carrying out coordination condensation reaction to obtain a lead complex;

(3) mixing a lead complex and an anhydrous methanol solution of cadmium sulfate, and then carrying out a displacement reaction to obtain the binuclear cadmium complex;

the substituted phenol is 2, 6-diformyl-4-methylphenol, 2, 6-diformyl-4-methoxyphenol, 2, 6-diformyl-4-fluorophenol, 2, 6-diformyl-4-chlorophenol or 2, 6-diformyl-4-bromophenol.

Preferably, the molar ratio of the substituted phenol to the lead acetate in the step (1) is 0.4-0.6: 0.4 to 0.6;

the molar volume ratio of the substituted phenol to the absolute ethyl alcohol is 0.4-0.6 mmol: 10-20 mL.

Preferably, the mixing mode in the step (1) is stirring, the rotating speed of the stirring is 200-400 rpm, and the stirring time is 1.8-2.2 h.

Preferably, the molar ratio of the N, N-bis (3-aminopropyl) -2-pyridinemethylamine in the step (2) to the substituted phenol in the step (1) is 0.4-0.6: 0.4 to 0.6;

the molar volume ratio of the anhydrous ethanol solution of the N, N-bis (3-aminopropyl) -2-pyridinemethylamine to the anhydrous ethanol solution of the N, N-bis (3-aminopropyl) -2-pyridinemethylamine is 0.4-0.6 mmol: 8-12 mL.

Preferably, the mixing in the step (2) is carried out by dropwise adding an absolute ethanol solution of N, N-bis (3-aminopropyl) -2-pyridinemethylamine into the mixed solution;

the dropping speed is 2-4 drops/second.

Preferably, the time of the coordination condensation reaction in the step (2) is 2.5-3.5 h.

Preferably, the molar ratio of the cadmium sulfate in the step (3) to the substituted phenol in the step (1) is 0.15-0.184: 0.4 to 0.6;

the molar volume ratio of the cadmium sulfate to the anhydrous methanol solution of the cadmium sulfate is 0.15-0.184 mmol: 10-20 mL.

Preferably, the step (3) is carried out by dripping an anhydrous methanol solution of cadmium sulfate into the lead complex;

the dropping speed is 2-4 drops/second;

the time of the replacement reaction is 3.5-4.5 h.

The invention also provides application of the binuclear cadmium complex in preparation of a nitric oxide fluorescent probe product.

The invention provides a binuclear cadmium complex, which is prepared by taking substituted phenol and N, N-bis (3-aminopropyl) -2-pyridine methylamine as raw materials and taking lead ions with large coordination numbers as a template through a coordination condensation reaction; the lead complex and cadmium sulfate are mixed, lead ions in the complex are replaced to obtain a binuclear cadmium complex, and the replaced lead ions form lead sulfate precipitates, so that subsequent filtration and separation are facilitated. The preparation method provided by the invention is simple, the core steps are coordination condensation reaction and replacement reaction, and the target complex can be efficiently prepared. Experiments prove that the binuclear cadmium complex prepared by the invention and nitric oxide can form a stable complex, has low detection limit, and can be used for preparing a nitric oxide fluorescent probe product.

Drawings

FIG. 1 is an infrared spectrum of a binuclear cadmium complex prepared in example 1;

FIG. 2 is an electrospray mass spectrum of the binuclear cadmium complex prepared in example 1;

FIG. 3 is a molecular structure diagram of a binuclear cadmium complex prepared in example 1;

FIG. 4 is a decahedral structural diagram of the binuclear cadmium complex prepared in example 1;

FIG. 5 is a graph of intermolecular hydrogen bonding of the dinuclear cadmium complex prepared in example 1;

FIG. 6 is a graph of hydrogen bonding along the a-axis of a binuclear cadmium complex prepared in example 1;

FIG. 7 is a color comparison graph of the binuclear cadmium complex prepared in example 1 with NO introduced;

FIG. 8 is a diagram of the UV absorption spectrum of the binuclear cadmium complex prepared in example 1 with NO introduced;

FIG. 9 is a graph of the UV emission of the binuclear cadmium complex prepared in example 1 with NO introduced;

FIG. 10 is an emission spectrum of the binuclear cadmium complex prepared in example 1 with NO introduced under visible light;

FIG. 11 is a graph of Δ A/b vs. Δ A at 450nm for the binuclear cadmium complex prepared in example 1.

Detailed Description

The invention provides a binuclear cadmium complex which has the following structure:

and R is methyl, methoxy, F, Cl or Br.

The invention also provides a preparation method of the binuclear cadmium complex, which comprises the following steps:

(1) mixing substituted phenol, lead acetate and absolute ethyl alcohol to obtain a mixed solution;

(2) mixing the mixed solution with an absolute ethyl alcohol solution of N, N-bis (3-aminopropyl) -2-pyridine methylamine, and then carrying out coordination condensation reaction to obtain a lead complex;

(3) mixing a lead complex and an anhydrous methanol solution of cadmium sulfate, and then carrying out a displacement reaction to obtain the binuclear cadmium complex;

the substituted phenol is 2, 6-diformyl-4-methylphenol, 2, 6-diformyl-4-methoxyphenol, 2, 6-diformyl-4-fluorophenol, 2, 6-diformyl-4-chlorophenol or 2, 6-diformyl-4-bromophenol.

In the present invention, the lead acetate in the step (1) is preferably lead acetate tetrahydrate.

In the invention, the molar ratio of the substituted phenol to the lead acetate in the step (1) is preferably 0.4-0.6: 0.4 to 0.6, and more preferably 0.45 to 0.55: 0.45 to 0.55, more preferably 0.48 to 0.52: 0.48 to 0.52.

In the invention, the molar volume ratio of the substituted phenol to the absolute ethyl alcohol is preferably 0.4-0.6 mmol: 10 to 20mL, more preferably 0.45 to 0.55 mmol: 12 to 18mL, more preferably 0.48 to 0.52 mmol: 14-16 mL.

In the invention, the mixing mode in the step (1) is preferably stirring, and the rotation speed of the stirring is preferably 200-400 rpm, more preferably 250-350 rpm, and even more preferably 280-320 rpm; the stirring time is preferably 1.8-2.2 h, more preferably 1.9-2.1 h, and even more preferably 1.95-2.05 h.

In the present invention, the molar ratio of N, N-bis (3-aminopropyl) -2-pyridinemethylamine in the step (2) to substituted phenol in the step (1) is preferably 0.4 to 0.6: 0.4 to 0.6, and more preferably 0.45 to 0.55: 0.45 to 0.55, more preferably 0.48 to 0.52: 0.48 to 0.52.

In the invention, the molar volume ratio of the N, N-bis (3-aminopropyl) -2-pyridinemethylamine to the N, N-bis (3-aminopropyl) -2-pyridinemethylamine solution in absolute ethanol is preferably 0.4-0.6 mmol: 8 to 12mL, more preferably 0.45 to 0.55 mmol: 9 to 11mL, more preferably 0.48 to 0.52 mmol: 9.5-10.5 mL.

In the present invention, the mixing in the step (2) is preferably performed by adding a drop of anhydrous ethanol solution of N, N-bis (3-aminopropyl) -2-pyridinemethylamine into the mixed solution.

In the invention, the dripping speed is preferably 2-4 drops/second, and more preferably 3 drops/second.

In the invention, the time of the coordination condensation reaction in the step (2) is preferably 2.5-3.5 h, more preferably 2.6-3.4 h, and even more preferably 2.8-3.2 h; the coordination condensation reaction is preferably carried out under a stirring condition, and the stirring speed is preferably 200-400 rpm, more preferably 250-350 rpm, and even more preferably 280-320 rpm.

In the present invention, taking the case where R is a methyl group as an example, the coordination condensation reaction in the step (2) is as follows:

in the present invention, the cadmium sulfate in the step (3) is preferably octahydrate of cadmium sulfate.

In the invention, the molar ratio of the cadmium sulfate in the step (3) to the substituted phenol in the step (1) is preferably 0.15-0.184: 0.4 to 0.6, more preferably 0.16 to 0.174: 0.45 to 0.55, more preferably 0.165 to 0.169: 0.48 to 0.52.

In the invention, the molar volume ratio of the cadmium sulfate to the anhydrous methanol solution of the cadmium sulfate is preferably 0.15-0.184 mmol: 10 to 20mL, more preferably 0.16 to 0.174 mmol: 12-18 mL, more preferably 0.165-0.169 mmol: 14-16 mL.

In the present invention, the mixing manner in the step (3) is preferably to drop the anhydrous methanol solution of cadmium sulfate into the lead complex.

In the invention, the dripping speed is preferably 2-4 drops/second, and more preferably 3 drops/second.

In the invention, the time of the replacement reaction is preferably 3.5-4.5 h, more preferably 3.6-4.4 h, and even more preferably 3.8-4.2 h; the displacement reaction is preferably carried out under a stirring condition, and the stirring speed is preferably 200 to 400rpm, more preferably 250 to 350rpm, and even more preferably 280 to 320 rpm.

In the invention, the displacement reaction is that cadmium ions in cadmium sulfate displace lead ions in a lead complex, lead ions and sulfate ions generate lead sulfate precipitates, sand core filtration is carried out after the stirring of the displacement reaction is finished, the filtered lead sulfate is washed, a reagent used for washing is preferably anhydrous methanol, the volume molar ratio of the anhydrous methanol to the substituted phenol in the step (1) is preferably 10-20 mL: 0.4 to 0.6mmol, more preferably 12 to 18 mL: 0.45 to 0.55mmol, more preferably 14 to 16 mL: 0.48-0.52 mmol; and after washing is finished, combining the filtrate and the washing liquid to obtain a mixed system.

In the present invention, the mixed system and the anhydrous methanol solution of sodium perchlorate are mixed to obtain a precipitate.

In the invention, the sodium perchlorate is preferably sodium perchlorate monohydrate, and the mass molar ratio of the sodium perchlorate to the substituted phenol in the step (1) is preferably 0.15-0.25 g: 0.4 to 0.6mmol, more preferably 0.16 to 0.24 g: 0.45 to 0.55mmol, more preferably 0.18 to 0.22 g: 0.48-0.52 mmol; the mass-volume ratio of the sodium perchlorate to the anhydrous methanol solution of the sodium perchlorate is preferably 0.15-0.25 g: 8 to 12mL, more preferably 0.16 to 0.24 g: 9-11 mL, more preferably 0.18-0.22 g: 9.5-10.5 mL.

In the invention, in a mixed system, the anhydrous methanol solution of sodium perchlorate is dripped, and the dripping speed is preferably 2-4 drops/second, and more preferably 3 drops/second.

In the invention, the mixing of the anhydrous methanol solution of sodium perchlorate and the mixing system is carried out under the condition of stirring, and the stirring speed is preferably 200-400 rpm, more preferably 250-350 rpm, and more preferably 280-320 rpm; and after the dropwise addition is finished, carrying out suction filtration on the solution by using a sand core to obtain a precipitate.

In the invention, the precipitate is dissolved in an ethanol acetonitrile solution and stands still, and the mass molar ratio of the ethanol acetonitrile solution to the substituted phenol in the step (1) is preferably 1.6-2.0 g: 0.4 to 0.6mmol, more preferably 1.7 to 1.9 g: 0.45 to 0.55mmol, more preferably 1.75 to 1.85 g: 0.48-0.52 mmol; the volume ratio of ethanol to acetonitrile in the ethanol acetonitrile solution is preferably 1: 0.5 to 1.5, and more preferably 1: 0.6 to 1.4, more preferably 1: 0.8 to 1.2; the standing time is preferably at least 14 days, more preferably at least 16 days, and still more preferably at least 18 days.

In the invention, the yellow blocky single crystal is obtained after the standing is finished, namely the binuclear cadmium complex.

In the present invention, taking the case where R is methyl as an example, the substitution reaction in the step (3) is as follows:

the invention also provides application of the binuclear cadmium complex in preparation of a nitric oxide fluorescent probe product.

In the invention, the nitric oxide fluorescent probe product is used for detecting and monitoring nitric oxide in biological medical treatment, food detection and environmental monitoring; the nitric oxide content of the measured object can be accurately measured.

The technical solutions provided by the present invention are described in detail below with reference to examples, but they should not be construed as limiting the scope of the present invention.

Example 1

Mixing 0.5mmol of 2, 6-diformyl-4-methylphenol, 0.5mmol of lead acetate tetrahydrate and 15mL of absolute ethyl alcohol, and stirring at the rotating speed of 300rpm for 2 hours to obtain a mixed solution; dripping 10mL of anhydrous ethanol solution containing 0.5mmol of N, N-bis (3-aminopropyl) -2-pyridine methylamine into the mixed solution at the speed of 3 drops/second, changing the solution from bright yellow turbidity to yellow transparent solution after the dripping is finished, stirring at the rotating speed of 300rpm for coordination condensation reaction, and obtaining a lead complex after 3 hours; then, the solution containing 0.167mmol of 3CdSO₄·8H₂Dropwise adding 15mL of absolute ethyl alcohol solution of O into the lead complex at the speed of 3 drops/second, wherein the solution becomes yellow and turbid after the dropwise adding is finished, stirring at the rotating speed of 300rpm for carrying out a displacement reaction, and filtering by using a sand core after stirring for 4 hours; washing the obtained lead sulfate precipitate with 15mL of anhydrous methanol, and combining the filtrate and the washing liquid to obtain a mixed system; controlling the rotating speed to be 300rpm, mixing the mixed system and the anhydrous methanol solution of sodium perchlorate in a dropping mode, dropping 10mL of the anhydrous methanol solution containing 0.2g of monohydrate sodium perchlorate into the mixed system at the speed of 3 drops/second, generating a large amount of yellow precipitates after the dropping is finished, and using a sand coreCarrying out suction filtration to obtain a precipitate; the precipitate was dissolved in 1.8g of ethanolic acetonitrile solution, the volume ratio of acetonitrile to ethanol being 1: 1, standing and volatilizing for 14 days to obtain 0.2g of yellow blocky single crystal, wherein the yield is 69 percent, and the binuclear cadmium complex is obtained.

The infrared spectrum analysis of the binuclear cadmium complex prepared in this example is shown in fig. 1. Elemental analysis (%): measured value: c is 45.12, H is 4.33, N is 10.21; calculated value (Cd)₂C₄₂H₅₀N₈O₁₀Cl₂) C is 44.93, H is 4.49 and N is 9.98. IR (KBr, cm)^-1)：3449(ν_O-H)，2923，2851(ν_CH)，1635(ν_C＝N)，1093(ν_ClO4 ^-)，622(δ_ClO4 ^-)。

The binuclear cadmium complex prepared in the embodiment is dissolved in absolute methanol for electrospray mass spectrometry, and the result is shown in fig. 2, wherein the abundance of the mass spectrum peak of m/z 1022.92 is 100%, and the abundance is attributed to [ Cd₂L⁹(ClO₄)]⁺And is the molecular ion peak, and L9 is the late ligand remaining after removal of the metal ion from the complex. The abundance of the mass peak of m/z 462.17 was also 100%, corresponding to [ Cd ]₂L⁹]²⁺Indicating that the complex was synthesized correctly. The abundance of other fragment peaks in the graph is very small, which indicates that the binuclear cadmium complex is Cd in methanol solution₂L⁹The groups can exist stably.

The crystal structure data and the structure optimization data of the binuclear cadmium complex prepared in this example are shown in table 1, and part of the bond length and bond angle data are shown in table 2.

TABLE 1

TABLE 2

The molecular structure diagram of the binuclear cadmium complex prepared in this example is shown in fig. 3, and it can be seen from the diagram that the whole macrocyclic ligand becomes distorted due to the coordination of the metal, and the angle between the two benzene ring planes on the ligand is 64.8 °. The decahedral structure of the complex is shown in FIG. 4. As can be seen from the figure, Cd1 combines with two imine nitrogen atoms N2 and N5 on the macrocyclic ligand, a tertiary amine nitrogen atom N3, a nitrogen atom N4 on the pyridine ring of a functional cantilever, two phenolic oxygen atoms O1 and O2, and an oxygen atom O14 on the perchlorate group to form a coordinated decahedral structure; cd1 is located at a distance from surrounding coordinating atoms in the rangeCd2 is combined with two imine nitrogen atoms N1 and N6 on the other side of the macrocyclic ligand, a tertiary amine nitrogen atom N7, a nitrogen atom N8 on the pyridine ring of the cantilever, a phenol oxygen atom O1 and O2 to form a 6-coordinated octahedral structure, and the distance range of Cd2 and the surrounding coordination atoms isThe difference between the coordination environments of Cd1 and Cd2 is that Cd2 has one perchlorate coordination less than Cd1, because the perchlorate coordinated with Cd1 occupies a large space, and other perchlorate cannot approach Cd2 to form a bond due to space resistance.

The diagram of the intermolecular hydrogen bond of the binuclear cadmium complex prepared in this example is shown in fig. 5, and it can be seen from the diagram that the intermolecular hydrogen bond of the complex firmly bonds molecules together, which plays an important role in forming a three-dimensional structure between the molecules of the complex. All hydrogen bond acceptors in the crystal structure are derived from oxygen atoms in the perchlorate radical, and all hydrogen bond donors are carbon atoms on the complex molecule. Perchloric acid coordinated to Cd atom in one moleculeThe oxygen atom O13 on the radical forms a hydrogen bond with the hydrogen atom H12B on the carbon atom C12 in another molecule to form a one-dimensional structure. The distance of H.O in the hydrogen bond C12-H12B.O 13 isThe hydrogen bonding angle was 117.0 °.

The hydrogen bonding diagram along the a-axis of the binuclear cadmium complex prepared in this example is shown in FIG. 6, and three oxygen atoms on the free perchlorate acting as counter charge in the molecule and three hydrogen atoms on the complex molecule form hydrogen bonds, namely C9-H9A.. O23, C22-H22.. O21, C29-H29A.. O22, wherein the distances of H9A.. O23, H22.. O21 and H29A.. O22 are respectivelyAndthe hydrogen bonding angles were 176.2 °, 172.4 ° and 158.6 °, respectively.

The hydrogen bonding data of the dinuclear cadmium complex prepared in this example are shown in table 3.

TABLE 3

Preparing the binuclear cadmium complex into the cadmium complex with the concentration of 5 multiplied by 10^-5And (3) introducing NO into the methanol solution of M, wherein the result is shown in figure 7, the left side in the figure is the complex solution before adding NO, and the right side in the figure is the complex solution after adding NO. The ultraviolet absorption spectrum obtained by performing ultraviolet absorption research on the methanol solution is shown in figure 8, wherein a curve a in figure 8 is the complex solution before adding NO, a curve b is the complex solution after adding NO, and as can be seen from figure 8, compared with the solution before adding NO, after adding NO, the charge-shift transition absorption peak from the ligand to the metal of the binuclear cadmium complex is red-shifted from 398nmBy 451nm, NO participates in coordination, so that a conjugated system from a ligand to a metal is prolonged, and structurally, perchlorate coordinated with cadmium in a binuclear cadmium complex is easy to leave (which is also proved in a conclusion of mass spectrum), so that NO with stronger coordination capacity is coordinated with a cadmium atom.

The prepared methanol solution containing the binuclear cadmium complex is irradiated under 302nm ultraviolet light, and the obtained luminescence graph is shown in fig. 9, wherein the left side in the graph is the complex solution before adding NO, and the right side in the graph is the complex solution after adding NO.

Irradiating the prepared methanol solution containing the binuclear cadmium complex under 400nm visible light excitation waves to obtain an emission spectrum as shown in figure 10, wherein a curve a is the complex solution without NO, and a curve b is the complex solution with NO, and it can be seen from the figure that the complex has a strong emission spectrum at 460nm when NO NO is added; the emission spectrum of the complex red-shifted to 506nm after the addition of NO and the fluorescence intensity increased by a factor of 3.2. The complex can be seen to generate low fluorescence excitation energy and cause little damage to cells; has good fluorescence property and high sensitivity to NO. This shows that the complex can be used as a potential NO fluorescent probe reagent product applied in organisms.

The binding constant of NO and the complex is researched by a binding equilibrium equation between NO and the complex by using an ultraviolet spectrophotometry, and an equation for the reaction of NO and the complex (expressed by C in the equation) can be expressed as follows:the binding constant of the complex and NO is K:[NO]，[C]，[C-NO]respectively, the equilibrium concentrations of NO, complex, and C-NO. The law of conservation of materials can be used as follows: [ C ]]+[C-NO]＝a(3)；[C-NO]+[NO]B (4); a and b represent the analytical concentrations of the complex and NO, respectively, [ C-NO ] in (4)]Can be ignored, i.e. because b is much larger than a, the formula [ C-NO]Can be ignored, i.e. [ NO ]]B (5); substituting formula (3) and formula (5) into formula (2) to obtain:let A_0,(C)＝ε_Cal,A_0,[NO]＝ε_NObl, then there is(8) (ii) a Substituting the formula (8) into the formula (6) to obtain:

a in formula (8)_0,(C)And A_0,(NO)The concentration can be determined from the complex solution and the saturated NO solution. The binding constant K is determined by calculating the slope of the curve by plotting Δ A/b against Δ A. FIG. 11 is a graph of Δ A/b vs. Δ A of a binuclear cadmium complex, in which the binding constant of NO to the binuclear cadmium complex is 7.4X 10³mol·L^–1。

The dinuclear cadmium complex prepared by the embodiment has obvious change of fluorescence color and intensity before and after NO addition, low excitation energy and high binding capacity to NO, so that the dinuclear cadmium complex has the application value of NO molecular probes.

Example 2

Mixing 0.4mmol of 2, 6-diformyl-4-chlorophenol, 0.6mmol of lead acetate tetrahydrate and 10mL of absolute ethyl alcohol, and stirring at the rotating speed of 200rpm for 1.8h to obtain a mixed solution; dripping 12mL of anhydrous ethanol solution containing 0.4mmol of N, N-bis (3-aminopropyl) -2-pyridine methylamine into the mixed solution at the speed of 3 drops/second, changing the solution from bright yellow turbidity to yellow transparent solution after the dripping is finished, stirring at the rotating speed of 200rpm for coordination condensation reaction, and obtaining a lead complex after 2.5 hours; then, the solution containing 0.15mmol of 3CdSO₄·8H₂Dropwise adding 20mL of anhydrous ethanol solution of O into the lead complex at the speed of 3 drops/second, wherein the solution turns yellow and turbid after the dropwise adding is finished, stirring at the rotating speed of 200rpm, and standingPerforming a reaction, stirring for 3.5 hours, and filtering by using a sand core; washing the obtained lead sulfate precipitate with 10mL of anhydrous methanol, and combining the filtrate and the washing liquid to obtain a mixed system; controlling the rotating speed to be 200rpm, mixing the mixed system and the anhydrous methanol solution of sodium perchlorate in a dropping mode, dropping 12mL of the anhydrous methanol solution containing 0.15g of monohydrate sodium perchlorate into the mixed system at the speed of 3 drops/second, generating a large amount of yellow precipitates after the dropping is finished, and performing suction filtration by using a sand core to obtain the precipitates; the precipitate was dissolved in 1.6g of ethanolic acetonitrile solution, the volume ratio of acetonitrile to ethanol being 0.5: 1, standing and volatilizing for 16 days to obtain 0.155g of yellow blocky single crystal, wherein the yield is 67 percent, and the binuclear cadmium complex is obtained. The binuclear cadmium complex prepared in this example has the same experiment as in example 1, has obvious change of fluorescence color and intensity before and after NO addition, low excitation energy, and excellent high binding capacity to NO.

Example 3

Mixing 0.6mmol of 2, 6-diformyl-4-chlorophenol, 0.4mmol of lead acetate tetrahydrate and 20mL of absolute ethyl alcohol, and stirring at the rotating speed of 400rpm for 2.2h to obtain a mixed solution; dripping 8mL of absolute ethanol solution containing 0.6mmol of N, N-bis (3-aminopropyl) -2-pyridine methylamine into the mixed solution at the speed of 3 drops/second, changing the solution from bright yellow turbidity to yellow transparent solution after the dripping is finished, stirring at the rotating speed of 400rpm for coordination condensation reaction, and obtaining a lead complex after 3.5 hours; then, the solution containing 0.184mmol of 3CdSO₄·8H₂Dropwise adding 10mL of absolute ethyl alcohol solution of O into the lead complex at the speed of 3 drops/second, wherein the solution becomes yellow and turbid after the dropwise adding is finished, stirring at the rotating speed of 400rpm for carrying out a displacement reaction, and filtering by using a sand core after stirring for 4.5 hours; washing the obtained lead sulfate precipitate with 20mL of anhydrous methanol, and combining the filtrate and the washing liquid to obtain a mixed system; controlling the rotating speed to be 400rpm, mixing the mixed system and the anhydrous methanol solution of sodium perchlorate in a dropping mode, dropping 8mL of the anhydrous methanol solution containing 0.25g of monohydrate sodium perchlorate into the mixed system at the speed of 3 drops/second, generating a large amount of yellow precipitates after the dropping is finished, and performing suction filtration by using a sand core to obtain the precipitates; dissolving the precipitate in 2.0g of ethanolic acetonitrile solution, acetonitrile and ethanolIs 1.5: 1, standing and volatilizing for 18 days to obtain 0.236g of yellow blocky single crystal, wherein the yield is 68 percent, and the binuclear cadmium complex is obtained. The binuclear cadmium complex prepared in this example has the same experiment as in example 1, has obvious change of fluorescence color and intensity before and after NO addition, low excitation energy, and excellent high binding capacity to NO.

From the above embodiments, the invention provides a binuclear cadmium complex, which is obtained through coordination condensation reaction and displacement reaction. In the complex provided by the invention, one cadmium atom coordination environment is in a heptahedral coordination configuration, the other cadmium atom is in a hexa-coordination octahedral configuration, and the two cadmium atoms are bridged by two phenolic oxygen atoms on a ligand. The molecule contains perchlorate ions which participate in coordination and dissociation, so that the complex has molecular self-assembly behavior. Oxygen atoms in the perchlorate radical and hydrogen atoms on the macrocyclic ligand easily form hydrogen bonds, so that one-dimensional chain structures and two-dimensional net structures are formed among molecules of the complex. The complex provided by the invention has good combination effect with NO, can form a stable complex, has low detection limit and low excitation energy of fluorescence emitted by the complex, has obvious changes of wavelength and intensity of fluorescence emission spectrum before and after NO is added, and is used as a probe product for detecting NO molecules in a body.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.