Cu(II)-based complex fluorescent probe and its preparation method and application

Abstract

The present invention relates to the field of fluorescence detection technology, and in particular to a Cu(II)-based complex fluorescent probe, its preparation method, and application. The present invention simultaneously coordinates two copper ions and a 3-PDCA ligand, and utilizes the multi-dentate bridged coordination sites of the ligand to form a special ring structure, thereby obtaining a Cu(II)-based complex fluorescent probe with a novel structure. The Cu(II)-based complex fluorescent probe has good stability and high Al 3+ The preparation method provided by the present invention has the advantages of simple process, convenient operation, high yield, good reproducibility, etc.

Description

Technical Field

[0001] The present invention relates to the technical field of fluorescence detection, and in particular to a Cu(II)-based complex fluorescent probe and a preparation method and application thereof. Background Art

[0002] Fluorescence detection of metal ions is a highly sensitive and selective analytical method widely used in environmental monitoring, biomedicine, and food safety. It exploits the specific coordination between metal ions and fluorescent probe molecules, altering the probe's fluorescence properties to achieve detection. Fluorescent probes typically emit a strong fluorescent signal in the absence of metal ions. However, upon binding to specific metal ions, the fluorescence intensity or wavelength undergoes a significant shift. This shift can be quickly and accurately measured and analyzed using a fluorescence spectrometer, enabling the detection and quantification of metal ions. Fluorescence detection technology offers the advantages of real-time and non-destructive performance, enabling efficient analysis in complex samples.

[0003] The present invention adopts solvent thermal synthesis conditions to synthesize Cu(II) based complex fluorescent probe and conducts metal ion detection performance test on it. The Cu(II) based complex shows good Al 3+ Detection performance, its Al 3+ The high sensitivity detection performance and excellent anti-interference ability of the complex are likely to become the mainstream synthesis direction of complex fluorescent probes. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to address the deficiencies of the above-mentioned prior art and provide a Cu(II)-based complex fluorescent probe and its preparation method and application. By program-controlling the temperature of the solvent thermal reaction, two copper ions and 3-PDCA ligands are coordinated at the same time, and a special ring structure is formed by utilizing the multi-dentate bridge coordination site of the ligand to prepare a Cu(II)-based complex. The complex has good stability and can be used in the presence of Al 3+ In terms of detection, its Al 3+ The high sensitivity detection performance and excellent anti-interference ability of the complex are likely to become the mainstream synthesis direction of complex fluorescent probes.

[0005] In order to solve the above technical problems, the present invention provides a Cu(II)-based complex fluorescent probe, the molecular formula of which is C 26 H 32 Cu2N4O 15 .

[0006] The present invention also provides a method for preparing the above-mentioned Cu(II)-based complex fluorescent probe, comprising the following steps:

[0007] S1. Add 3-PDCA ligand to the alcohol compound and stir evenly to obtain a suspension of the alcohol compound;

[0008] S2. Dissolve copper nitrate trihydrate in deionized water and stir to obtain a copper nitrate trihydrate solution;

[0009] S3. Add the copper nitrate trihydrate solution prepared in S2 to the alcohol compound suspension prepared in S1, stir evenly, and after solvent thermal reaction, filter, wash and vacuum dry in sequence to obtain a Cu(II)-based complex fluorescent probe.

[0010] According to the preparation method provided by the present invention, the alcohol compound in S1 is methanol or ethanol. When the alcohol compound is methanol, the molar volume ratio of the methanol to the 3-PDCA ligand is 3 mL:0.05 mmol; when the alcohol compound is ethanol, the volume ratio of the ethanol to the 3-PDCA ligand is 2-4 mL:0.05 mmol.

[0011] According to the preparation method provided by the present invention, the molar volume ratio of copper nitrate trihydrate and deionized water in S2 is 0.1 mmol: 1-2 mL;

[0012] According to the preparation method provided by the present invention, the temperature control procedure of the solvent thermal reaction in S3 is: heating to 100°C and maintaining for 48 hours, and then cooling to room temperature, the heating rate during the heating process is 0.1°C / min, and the cooling rate during the cooling process is 0.1°C / min.

[0013] According to the preparation method provided by the present invention, the volume ratio of the hydrated copper nitrate solution and the alcohol compound suspension in S3 is 1:2.

[0014] According to the preparation method provided by the present invention, the detergent selected for washing in S3 is a mixed mixture of ethanol and deionized water, and the volume ratio of ethanol to deionized water in the mixed detergent is 1:1.

[0015] According to the preparation method provided by the present invention, the stirring speed in S1, S2 and S3 is 1200 rpm.

[0016] The present invention also provides an application of the Cu(II)-based complex fluorescent probe, wherein the Cu(II)-based complex fluorescent probe is used for Al 3+ Sensitive detection of ions.

[0017] Compared with the prior art, the present invention has the following advantages:

[0018] (1) The present invention simultaneously coordinates two copper ions and 3-PDCA ligands, and uses the multi-dentate bridge coordination sites of the ligands to form a special ring structure, thereby obtaining a Cu(II)-based complex fluorescent probe with a novel structure. The Cu(II)-based complex fluorescent probe can be used as an Al 3+ Specific fluorescent probes for sensitive detection.

[0019] (2) The Cu(II)-based complex fluorescent probe in the present invention has the advantages of simple process, convenient operation, high yield, and good reproducibility. More importantly, it is possible to specifically detect metal ions based on the complex fluorescent probe, which can fill the gap in the traditional fluorescence detection industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of the molecular structure of the Cu(II)-based complex fluorescent probe;

[0021] Figure 2 Schematic diagram of the ring structure of the Cu(II)-based complex fluorescent probe;

[0022] Figure 3 is the powder X-ray diffraction pattern of the Cu(II)-based complex fluorescent probe;

[0023] Figure 4 This is the solid fluorescence image of the Cu(II)-based complex fluorescent probe;

[0024] Figure 5 Schematic diagram of specific detection of Cu(II)-based complex fluorescent probe;

[0025] Figure 6 Schematic diagram of the fluorescence enhancement kinetics of Cu(II)-based complex fluorescent probe;

[0026] Figure 7 Schematic diagram of fluorescence changes and fitting of Cu(II)-based complex fluorescent probe. DETAILED DESCRIPTION

[0027] Example 1

[0028] This embodiment provides a method for preparing a Cu(II)-based complex fluorescent probe, comprising the following steps:

[0029] S1. Take 0.05 mmol (27.4 mg) of 1-(3-carboxyphenyl)-5-methyl-4-oxo-1,4-dihydropyridazine-3-carboxyl (3-PDCA) ligand and add it to 2 mL of ethanol. Stir at 1200 rpm to obtain an ethanol suspension.

[0030] S2. Dissolve 0.1 mmol of copper nitrate trihydrate in 1 mL of deionized water and stir at 1200 rpm to obtain a copper nitrate trihydrate solution.

[0031] S3, adding the copper nitrate trihydrate solution prepared in S2 to the ethanol suspension prepared in S1, and stirring at a speed of 1200 rpm to obtain a mixed suspension, wherein the volume ratio of the copper nitrate trihydrate solution to the ethanol suspension is 1:2;

[0032] The mixed suspension was placed in a high-pressure reactor and subjected to a solvothermal reaction under programmed temperature control. The specific temperature control program was as follows: heating to 100°C and maintaining for 48 hours, and then cooling to room temperature. The heating rate during the heating process was 0.1°C / min, and the cooling rate during the cooling process was 0.1°C / min.

[0033] After the solvent thermal reaction is completed, the solution in the reactor is filtered and then washed three times with a mixed detergent of ethanol and deionized water in a volume ratio of 1:1, and then vacuum dried to obtain blue granular crystals, which are Cu(II)-based complex fluorescent probes with the molecular formula C 26 H 32 Cu2N4O 15 , the yield is 60.3%

[0034] The chemical structural formula of the raw material 3-PDCA ligand used in this embodiment is:

[0035]

[0036] 3-PDCA is a multi-dentate bridging organic acid ligand that functions to increase coordination sites. It has good chemical stability and reactivity, and can produce stable complexes with fluorescent properties.

[0037] At the same time, two copper ions were coordinated with the 3-PDCA ligand, and the multi-dentate bridging coordination sites of the ligand were used to form a special ring structure, resulting in a Cu(II)-based complex fluorescent probe with a novel structure.

[0038] The metal ion detection performance test found that the Cu(II)-based complex fluorescent probe has good stability and can be used as an Al 3+ Fluorescent probe for ion-sensitive detection.

[0039] Example 2

[0040] This embodiment provides a method for preparing a Cu(II)-based complex fluorescent probe, comprising the following steps:

[0041] S1. Add 0.05 mmol of 3-PDCA ligand to 3 mL of methanol and stir at 1200 rpm to obtain a methanol suspension.

[0042] S2. Dissolve 0.1 mmol of copper nitrate trihydrate in 1 mL of deionized water and stir at 1200 rpm to obtain a copper nitrate trihydrate solution.

[0043] S3, adding the copper nitrate trihydrate solution prepared in S2 to the methanol suspension prepared in S1, and stirring at a speed of 1200 rpm to obtain a mixed suspension, wherein the volume ratio of the copper nitrate trihydrate solution to the methanol suspension is 1:2;

[0044] The mixed suspension was placed in a high-pressure reactor and subjected to a solvothermal reaction under programmed temperature control. The specific temperature control program was as follows: heating to 100°C and maintaining for 48 hours, and then cooling to room temperature. The heating rate during the heating process was 0.1°C / min, and the cooling rate during the cooling process was 0.1°C / min.

[0045] After the solvent thermal reaction is completed, the solution in the reactor is filtered and then washed three times with a mixed detergent of ethanol and deionized water in a volume ratio of 1:1, and then vacuum dried to obtain light blue granular crystals, which are Cu(II)-based complex fluorescent probes with the molecular formula C 26 H 32 Cu2N4O 15 , the yield is 61.5%

[0046] Example 3

[0047] This embodiment provides a method for preparing a Cu(II)-based complex fluorescent probe, comprising the following steps:

[0048] S1. Take 0.05 mmol of 3-PDCA ligand and add it to 4 mL of ethanol. Stir it at 1200 rpm to obtain an ethanol suspension.

[0049] S2. Dissolve 0.1 mmol of copper nitrate trihydrate in 1 mL of deionized water and stir at 1200 rpm to obtain a copper nitrate trihydrate solution.

[0050] S3, adding the copper nitrate trihydrate solution prepared in S2 to the ethanol suspension prepared in S1, and stirring at a speed of 1200 rpm to obtain a mixed suspension, wherein the volume ratio of the copper nitrate trihydrate solution to the methanol suspension is 1:2;

[0051] The mixed suspension was placed in a high-pressure reactor and subjected to a solvothermal reaction under programmed temperature control. The specific temperature control program was as follows: heating to 100°C and maintaining for 48 hours, then cooling to room temperature. The heating rate during the heating process was 0.1°C / min, and the cooling rate during the cooling process was 0.1°C / min.

[0052] After the solvent thermal reaction is completed, the solution in the reactor is filtered and then washed three times with a mixed detergent of ethanol and deionized water in a volume ratio of 1:1, and then vacuum dried to obtain light blue granular crystals, which are Cu(II)-based complex fluorescent probes with the molecular formula C 26 H 32 Cu2N4O 15 , the yield is 58.6%

[0053] Example 4

[0054] This embodiment provides a method for preparing a Cu(II)-based complex fluorescent probe, comprising the following steps:

[0055] S1. Take 0.05 mmol of 3-PDCA ligand and add it to 2 mL of ethanol. Stir it at 1200 rpm to obtain an ethanol suspension.

[0056] S2. Dissolve 0.1 mmol of copper nitrate trihydrate in 2 mL of deionized water and stir at 1200 rpm to obtain a copper nitrate trihydrate solution.

[0057] S3, adding the copper nitrate trihydrate solution prepared in S2 to the ethanol suspension prepared in S1, and stirring at a speed of 1200 rpm to obtain a mixed suspension, wherein the volume ratio of the copper nitrate trihydrate solution to the methanol suspension is 1:2;

[0058] The mixed suspension was placed in a high-pressure reactor and subjected to a solvothermal reaction under programmed temperature control. The specific temperature control program was as follows: heating to 100°C and maintaining for 48 hours, then cooling to room temperature. The heating rate during the heating process was 0.1°C / min, and the cooling rate during the cooling process was 0.1°C / min.

[0059] After the solvent thermal reaction is completed, the solution in the reactor is filtered and then washed three times with a mixed detergent of ethanol and deionized water in a volume ratio of 1:1, and then vacuum dried to obtain light blue granular crystals, which are Cu(II)-based complex fluorescent probes with the molecular formula C 26 H 32 Cu2N4O 15 , the yield is 57.8%

[0060] Comparative Example 1

[0061] In this comparative example, compared with Example 1, the solvent thermal reaction in S3 was eliminated and the evaporation was carried out slowly at room temperature. The specific operation was as follows:

[0062] S1. Take 0.05 mmol of 3-PDCA ligand and add it to 2 mL of ethanol. Stir it at 1200 rpm to obtain an ethanol suspension.

[0063] S2. Dissolve 0.1 mmol of copper nitrate trihydrate in 1 mL of deionized water and stir at 1200 rpm to obtain a copper nitrate trihydrate solution.

[0064] S3, adding the copper nitrate trihydrate solution prepared in S2 to the ethanol suspension prepared in S1, and stirring at a speed of 1200 rpm to obtain a mixed suspension, wherein the volume ratio of the copper nitrate trihydrate solution to the methanol suspension is 1:2;

[0065] The mixed suspension was placed in a container, sealed with plastic wrap and small holes were pierced in the plastic wrap. The sealed and pierced container was placed in a room temperature environment. After slow evaporation, no testable crystals were obtained.

[0066] Comparative Example 2

[0067] In this comparative example, compared with Example 1, the washed product was evaporated directly at room temperature without vacuum drying. The specific steps are as follows:

[0068] S1. Take 0.05 mmol of 3-PDCA ligand and add it to 2 mL of ethanol. Stir it at 1200 rpm to obtain an ethanol suspension.

[0069] S2. Dissolve 0.1 mmol of copper nitrate trihydrate in 1 mL of deionized water and stir at 1200 rpm to obtain a copper nitrate trihydrate solution.

[0070] S3, adding the copper nitrate trihydrate solution prepared in S2 to the ethanol suspension prepared in S1, and stirring at a speed of 1200 rpm to obtain a mixed suspension, wherein the volume ratio of the copper nitrate trihydrate solution to the methanol suspension is 1:2;

[0071] The mixed suspension was placed in a high-pressure reactor and subjected to a solvothermal reaction under programmed temperature control. The specific temperature control program was as follows: heating to 100°C and maintaining for 48 hours, then cooling to room temperature. The heating rate during the heating process was 0.1°C / min, and the cooling rate during the cooling process was 0.1°C / min.

[0072] After the solvent thermal reaction is completed, the solution in the reactor is filtered and then washed three times with a mixed detergent of ethanol and deionized water in a volume ratio of 1:1. The washed product is placed in a container, sealed with plastic wrap and small holes are pierced in the plastic wrap. The sealed and pierced container is placed in a room temperature environment to allow the remaining solvent to slowly evaporate, and finally a powdered solid is obtained.

[0073] Example 5

[0074] The elemental analysis of the light blue rod-shaped crystals finally obtained in Example 1 showed that: 26 H 32 Cu2N4O 15 , molecular weight 767.73.

[0075] The light blue rod-shaped crystals obtained in Example 1 were tested using a Bruker SMART 1000CCD diffractometer, with a specific wavelength of The MoKα ray and ω scanning mode were used. The collected diffraction points were restored using the SAINT program and corrected using the SADABS program. Based on the full-angle least squares method, the crystallographic software SHELXTL 5.1 package was used to find the coordinates of all non-hydrogen atoms on the difference Fourier map using a direct method. Then, all non-hydrogen atoms were refined using anisotropic refinement. The schematic diagram of the solved molecular structure is shown below. Figure 1 As shown, the ring structure is Figure 2 The obtained crystallographic parameters are shown in Table 1:

[0076] Table 1

[0077]

[0078]

[0079] R1=∑||F o |-|F c || / ∑|F o |,wR2=[∑w(F o 2 -F c 2 ) 2 / ∑w(F o 2 ) 2 ] 1 / 2 .

[0080] As shown in Table 1, the R1 value is less than 0.05, indicating that there is no error in the structural analysis and the true molecular structure is obtained.

[0081] The powder XRD diffraction characterization of Bruker D8 AVANCE was used to verify the phase purity and repeatability of the blue granular crystals finally obtained in Example 1. The results are as follows: Figure 3 As shown, the simulation values ​​fit well with the experimental values, indicating good phase purity and repeatability.

[0082] Example 6

[0083] In this example, the metal ion detection performance of the blue granular crystals finally obtained in Example 1 was evaluated.

[0084] 25 mg of the blue granular crystals finally obtained in Example 1 were taken and the solid fluorescence emission performance was tested using an EDINBURGH FLS-1000 transient and steady-state fluorescence spectrometer. Figure 4 As shown in the results, it can be seen that under 335nm excitation, the maximum emission peak is found at 408nm.

[0085] 2 mg of the blue granular crystals finally obtained in Example 1 were placed in 4 mL of deionized water and ultrasonically dispersed uniformly. 5 mmol of 13 metal ions were used for the experiment. Figure 5 As shown in the results, the Cu(II)-based complex fluorescent probe is sensitive to Al 3+ It showed good fluorescence enhancement effect, and its fluorescence enhancement kinetics and stability were tested, such as Figure 6 As shown, the results show that with the increase of Al 3+ With the addition of ions, the fluorescence intensity of the Cu(II)-based complex fluorescent probe gradually increased, reached the maximum value in about 30s and showed good stability. 3+ The Cu(II)-based complex fluorescent probe was titrated with ion solution (3 μL was added each time), and it was found that its fluorescence intensity increased with the increase of Al 3+ The fluorescence intensity of the ions gradually increases with each addition, and the maximum fluorescence value at 408 nm is consistent with that of Al 3+ The concentration gradient of ions is plotted to understand their changing relationship. The results show that in the range of 0-6×10 -4 In the concentration range of mol / L, Al 3+ There is a good linear relationship between the concentration of Cu(II) and the fluorescence intensity of the Cu(II) complex fluorescent probe (R 2 =0.9917) Figure 7 shown.

[0086] The limit of detection (LOD) was further calculated by 3σ / slope (σ is the blank standard deviation of 11 solid-state emission intensities). 3+ The ion detection limit is 2.11×10 -5mol / L, demonstrating its potential as a fluorescent probe for metal ion detection.

[0087] From the above experimental results, it can be seen that the Cu(II)-based complex fluorescent probe in the present invention has a high Al 3+ It has the advantages of high detection performance and good stability, simple process, easy operation, high yield and good reproducibility. More importantly, it is possible to specifically detect metal ions with fluorescent probes based on complexes, which can fill the gap in the traditional fluorescence detection industry.

[0088] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent variation made to the above embodiment based on the essence of the invention technology shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A Cu(II)-based complex fluorescent probe, characterized in that The molecular formula of the Cu(II)-based complex fluorescent probe is C 26 H 32 Cu2N4O 15 The crystal system of the Cu (II)-based complex fluorescent probe is an orthorhombic system, the space group of the Cu (II)-based complex fluorescent probe is Imma, and the unit cell parameters of the Cu (II)-based complex fluorescent probe are a=24.4188(7) Å, b=40.6903(8) Å, c=7.0896(2) Å, α= 90.00°, β= 90.00° and γ= 90.00°.

2. A method for preparing a Cu(II)-based complex fluorescent probe as claimed in claim 1, characterized in that: The following steps are involved: S1. Add 3-PDCA ligand to an alcohol solvent and stir evenly to obtain an alcohol solvent suspension; The structural formula of the 3-PDCA ligand is: ； S2. Dissolve copper nitrate trihydrate in deionized water and stir to obtain a copper nitrate trihydrate solution; S3. Add the copper nitrate trihydrate solution prepared in S2 to the alcohol solvent suspension prepared in S1, stir evenly, and after solvent thermal reaction, filter, wash and vacuum dry in sequence to obtain a Cu (II)-based complex fluorescent probe.

3. The preparation method according to claim 2, characterized in that: The alcohol solvent in S1 is methanol or ethanol. When the alcohol solvent is methanol, the molar volume ratio of the methanol to the 3-PDCA ligand is 3 mL:0.05 mmol; when the alcohol solvent is ethanol, the volume ratio of the ethanol to the 3-PDCA ligand is 2-4 mL:0.05 mmol.

4. The preparation method according to claim 2, characterized in that The molar volume ratio of copper nitrate trihydrate and deionized water in S2 is 0.1 mmol:1-2 mL.

5. The preparation method according to claim 2, characterized in that: The temperature control program of the solvothermal reaction in S3 is: heating to 100°C and maintaining for 48 h, then cooling to room temperature, the heating rate of the heating is 0.1°C / min, and the cooling rate of the cooling is 0.1°C / min.

6. The preparation method according to claim 2, characterized in that: The volume ratio of the copper nitrate trihydrate solution and the alcohol solvent suspension in S3 is 1:

2.

7. The preparation method according to claim 2, characterized in that: The detergent selected for washing in S3 is a mixture of ethanol and deionized water, and the volume ratio of ethanol to deionized water in the mixed detergent is 1:

1.

8. The preparation method according to claim 2, characterized in that: The stirring speed in S1, S2 and S3 was 1200 rpm.

9. A use of the Cu(II)-based complex fluorescent probe as claimed in claim 1, characterized in that: The Cu(II)-based complex fluorescent probe for Al 3+ Sensitive detection of ions, said detection being for non-therapeutic or diagnostic purposes.

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