Cyclo-metalated palladium complexes, methods for their preparation and use
By employing the self-assembled nanowire technology of cyclic palladium complexes, the problems of time-consuming and costly traditional methods have been solved, enabling highly sensitive detection of bisulfite and live-cell imaging, with the advantages of low cost and real-time monitoring.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-10-12
- Publication Date
- 2026-05-15
AI Technical Summary
Existing methods for detecting bisulfite are time-consuming, require expensive instruments and complex procedures, and traditional fluorescent probes lack sufficient sensitivity at low concentrations, making it difficult to achieve live cell imaging.
A class of cyclic palladium metallization complexes were developed as fluorescent probes. They self-assembled into nanowires through Pd-Pd interactions, enabling specific fluorescent detection of bisulfite ions. This method is suitable for detecting bisulfite ions in aqueous solutions and living cells.
It achieves highly sensitive detection of bisulfite, is easy to operate, low in cost, can monitor in real time, and can be used for live cell imaging and tumor treatment.
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Figure CN117362354B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a class of cyclic palladium metallization complexes and their applications in the detection of bisulfite, biomedicine, and bioimaging, belonging to the field of biomedical detection and imaging. Background Technology
[0002] Transition metal complexes are considered to have the potential to serve as phosphorescent sensors for metal ions, anions, and biomolecules due to their favorable photophysicochemical properties, including large Stokes shifts, long luminescence lifetimes, resistance to photobleaching, ligand tunability, and efficient cellular uptake. The photophysical properties of near-square planar cyclic palladium(II) / platinum(II) complexes have been extensively studied over the past few decades due to their interesting spectral and luminescent properties and their metal-metal interactions. The d-phase complexes with Ru and Ir... 8 Compared to octahedral coordination geometry, d 8 Pt and Pd complexes typically employ a square planar coordination configuration with vacancy-based axial coordination and low steric effects. This configuration is better suited for intermolecular interactions, such as metal-metal interactions, ligand π-π interactions, and interactions with solvent molecules. These interactions can significantly enhance the sensitivity of phosphorescence to its surrounding environment. (Square planar d) 8 The stacking form of Pt and Pd metal complexes typically exhibits metal-metal-ligand charge transfer (MMLCT) mediated by metal-metal interactions, resulting in excited states that may show significant redshift and emission.
[0003] Changes in bisulfite concentration are of great significance for environmental protection and food testing, and developing fluorescent probes to detect these changes presents a significant challenge. Currently, various traditional methods for detecting bisulfite include flow injection analysis, electrochemistry, chromatography, and titration analysis; however, these methods are mostly time-consuming, requiring expensive instruments, multiple reagents, and complex procedures. In contrast, fluorescent probe technology has inherent advantages due to its simplicity, visualization, rapid response, real-time monitoring, and high sensitivity and selectivity. Over the past decade, many fluorescent probes for detecting bisulfite have been reported; however, most of them require the participation of an organic co-solvent to ensure probe relevance to HSO3-. - High affinity for bisulfite, while only a few can detect bisulfite in 100% aqueous solution, and some bisulfite probes are sensitive to low HSO3. - The content detection is not sensitive enough and lacks live cell imaging. Summary of the Invention
[0004] To address the shortcomings of existing technologies, this invention provides a class of cyclic palladium metallization complexes. These complexes, acting as "on-off" phosphorescent probes, are induced by bisulfite ions in aqueous solutions, resulting in Pd-Pd interactions between molecules that induce self-assembly to form nanowires emitting blue light. This enables specific fluorescence detection of bisulfite ions and can also serve as a fluorescent diagnostic probe for bisulfite ions in living cells.
[0005] The structural formula of the cyclic metallized palladium complex of the present invention is shown in Formula I:
[0006] Formula I
[0007] in, Selected from
[0008] Selected from The specific steps for preparing the cyclic palladium metallization complex are as follows:
[0009] (1) Under a protective atmosphere, palladium acetate and an aromatic cyclic compound are dissolved in an alcohol solvent to obtain a mixed solution A. The mixed solution A is stirred and reacted at room temperature for 24-48 h. The reaction solution is then evaporated to dryness, dissolved in CH2Cl2, and then hexane is added. Solid-liquid separation is performed to obtain a solid. The solid is washed and vacuum dried to obtain a palladium acetate bridged dimer. The molar ratio of palladium acetate to the aromatic cyclic compound is 1:1-3. The aromatic cyclic compound is selected from...
[0010] (2) Under a protective atmosphere, the palladium acetate bridged dimer obtained in step (1) and the lithium salt are dissolved in a mixed solvent of acetone and ultrapure water to obtain mixed solution B. Mixed solution B is stirred and reacted at room temperature for 12-72 h, and then dried under vacuum to obtain palladium chloride bridged dimer; the lithium salt is lithium chloride, and the molar ratio of palladium acetate bridged precursor to lithium salt is 1:6.5-20; the volume ratio of acetone to ultrapure water in the mixed solvent is 13:5-40:15;
[0011] (3) Under a protective atmosphere, the palladium chloride bridged dimer obtained in step (1) and the silver salt are dissolved in acetonitrile solvent to obtain mixed solution C. Mixed solution C is stirred and reacted at room temperature for 24-48 hours to remove chloride. The solid and liquid phases are separated, and the liquid phase is the intermediate product. The silver salt is silver trifluoromethanesulfonate, and the molar ratio of palladium chloride bridged dimer to silver salt is 1:1-3.
[0012] (4) Under a protective atmosphere, the intermediate product obtained in step (3) is mixed evenly with a bipyridine compound, and the mixture is refluxed and stirred at 60-70℃ for 24-36 h to precipitate. The precipitate is washed and dried to obtain a cyclic palladium metallized complex; the bipyridine compound is selected from... The molar ratio of the palladium bridging precursor to the bipyridine compound is 1:1-3.
[0013] when for hour, for At that time, the structural formula of the cyclic palladium metallization complex is Name it 1a.
[0014] when for hour, for At that time, the structural formula of the cyclic palladium metallization complex is Name it 1b.
[0015] when for hour, for At that time, the structural formula of the cyclic palladium metallization complex is Name it 2a.
[0016] when for hour, for At that time, the structural formula of the cyclic palladium metallization complex is Name it 2b.
[0017] when for hour, for At that time, the structural formula of the cyclic palladium metallization complex is It is named 3a.
[0018] when for hour, for At that time, the structural formula of the cyclic palladium metallization complex is Name it 3b.
[0019] Preferably, the protective atmosphere is N2, Ar, or He.
[0020] The cyclic palladium metallization complex is used as a fluorescent probe in the detection of bisulfite, in the preparation of cell diagnostic imaging reagents, and in the preparation of antitumor drugs.
[0021] Beneficial effects:
[0022] The cyclic palladium (II) complexes of this invention not only possess antitumor activity and can be used in the preparation of antitumor drugs, but also, under the induction of bisulfite ions in the solution environment, the synthesized cyclic palladium (II) complexes self-assemble into nanowires through Pd-Pd interactions. Upon excitation by a 320 nm light source, they emit blue / violet fluorescence at 350-450 nm, and this blue / violet luminescence is observable to the naked eye under fluorescent conditions. Therefore, these cyclic palladium (II) complexes can be applied in fields such as ion detection fluorescent probes, tumor therapy, and fluorescent colorimetric materials. Furthermore, they exhibit high sensitivity, low detection cost, convenient operation, rapid measurement, and real-time detection capabilities for the in vitro detection of bisulfite ions in aqueous solutions. Attached Figure Description
[0023] Figure 1 The proton NMR spectrum of complex 2a ( 1 H-NMR (d6-DMSO) plot;
[0024] Figure 2 The proton NMR spectrum of complex 2b ( 1 H-NMR (d6-DMSO) plot;
[0025] Figure 3 This is the high-resolution mass spectrum of complex 2a;
[0026] Figure 4 This is the high-resolution mass spectrum of complex 2b;
[0027] Figure 5 These are the UV and fluorescence spectra of complex 2a (20 μmol / L) in five different solvents (PBS, H2O, CH3CN, CH2Cl2, CHCl3); Figure A is the UV spectrum, and Figure B is the fluorescence spectrum.
[0028] Figure 6 The images show the UV and fluorescence spectra of complex 2b (20 μmol / L) in five different solvents (PBS, H2O, CH3CN, CH2Cl2, CHCl3), where Figure A is the UV spectrum and Figure B is the fluorescence spectrum.
[0029] Figure 7 The images show fluorescence spectra of different anions titrated with complex 2a (20 μM), with the left image being the fluorescence intensity spectrum and the right image being the fluorescence intensity bar chart.
[0030] Figure 8 The images show fluorescence spectra of different anions titrated with complex 2b (20 μM), with the left image being the fluorescence intensity spectrum and the right image being the fluorescence intensity bar chart.
[0031] Figure 9These are complexes 1a, 1b, 2a, 2b, 3a, and 3b of equal concentration but different structures, and their effects on HSO4 in solution. - Fluorescence response diagram of (5 mmol / L);
[0032] Figure 10 The images show the fluorescence emission spectra of complexes 1a-b (20 μM) with different structures at the same concentration in different solvents. The left image represents 1a, and the right image represents 1b. Figure 1 b;
[0033] Figure 11 The images show the fluorescence emission spectra of complexes 2a-b (20 μM) with different structures at the same concentration in different solvents. The left image represents 2a, and the right image represents 2b. Figure 2 b;
[0034] Figure 12 The images show the fluorescence emission spectra of complexes 3a-b (20 μM) with different structures at the same concentration in different solvents. The left image represents 3a, and the right image represents 3b. Figure 3 b;
[0035] Figure 13 This is the result of tumor cell uptake of complex 1b and colocalization of subcellular organelle dyes;
[0036] Figure 14 It is the coordination compounds 1a and 1b in HSO3 - Tyndall effect and DLS diagram of nano-ions assembled under action. Detailed Implementation
[0037] The present invention will be further described in detail below through embodiments, but the scope of protection of the present invention is not limited to the content described.
[0038] The structures of the compounds prepared in the embodiments of this invention were determined by 1H NMR spectroscopy and mass spectrometry. Where specific techniques or conditions are not specified in the embodiments, they were performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Materials or equipment whose manufacturers are not specified are all conventional products that can be purchased, and methods used are conventional methods unless otherwise specified.
[0039] Example 1: Synthesis of Complex 1a
[0040] (1) Under a nitrogen atmosphere, palladium acetate and 2-(2-thiophene)pyridine (tpy) were mixed in a molar ratio of 1:2.1 and dissolved in ethanol to obtain solution A. Solution A was stirred and reacted at room temperature for 24 h. During the reaction, a yellow solid was precipitated. After the reaction was completed, the reaction solution was dried by rotary evaporation to obtain a yellow solid. The yellow solid was dissolved in a trace amount (1-2 ml) of CH2Cl2 and then hexane was added for precipitation. The solid was collected by solid-liquid separation. The solid was washed successively with hexane and diethyl ether and dried under vacuum at 50 °C to obtain palladium acetate bridged dimer [Pd(tpy)OAc]2.
[0041] (2) Under a nitrogen atmosphere, [Pd(tpy)(OAc)]2 (100 mg, 0.15 mmol) and lithium chloride (42.4 mg, 0.975 mmol) were dissolved in a mixture of acetone and ultrapure water (26 ml acetone, 10 ml water) to obtain solution B. Solution B was reacted at room temperature for 12 h, and the solid and liquid phases were separated. The solid was dried under vacuum to obtain a yellow palladium chloride bridged dimer [Pd(tpy)Cl]2 (74.6 mg, 80.56%).
[0042] (3) Under a nitrogen atmosphere, palladium chloride bridged dimer [Pd(tpy)Cl]2 (74.6 mg, 0.12 mmol) and AgCF3SO3 (63.7 mg, 0.24 mmol) were dissolved in 15 ml of CH3CN solvent to obtain solution C. Solution C was reacted at room temperature for 24 h. The solid and liquid phases were separated, and the grayish-white AgCl precipitate was removed. The liquid phase was the intermediate product.
[0043] (4) Under a nitrogen atmosphere, 2,2'-bipyridine (bpy) (38.4 mg, 0.24 mmol) was added to the intermediate product, and the mixture was refluxed at 60 °C for 24 h. After the reaction was completed, the solid and liquid were separated, and the solid was washed with water and ether in sequence and dried at 60 °C to obtain a yellow solid complex 1a; the yield was 72.1%.
[0044] The structural formula of the complex 1a is as follows: MRI 1 The H-spectrum and mass spectrometry data are as follows: 1 HNMR (600MHz, DMSO-d6) δ = 9.00 (d, J = 5.7, 1H), 8.69 (s, 3H), 8.39 (d, J = 8.0, 2H), 8.01 (t, J = 7.8, 1H), 7.95 (t, J = 7. 7,2H),7.63(d,J=8.0,1H),7.59(d,J=5.0,1H),7.54(d,J=5.1,1H),7.48–7.44(m,1H),7.29(t,J=6.6,1H).ESI-MS m / z:421.9973[M-CF3SO3 - ]+ .
[0045] Example 2: Synthesis of Complex 1b
[0046] Steps (1), (2), and (3) are the same as steps (1), (2), and (3) in Embodiment 1;
[0047] Under a nitrogen atmosphere, 1,10-phenanthroline (phen) (44.7 mg, 0.24 mmol) was added to the intermediate product, and the mixture was refluxed at 65 °C for 28 h. After the reaction was completed, the solid and liquid were separated, and the solid was washed with water and ether in sequence and dried at 60 °C to give a yellow solid complex 1b; the yield was 80.6%.
[0048] The structural formula of the complex 1b is as follows: MRI 1 The H-spectrum and mass spectrometry data are as follows: 1 H NMR (600MHz, DMSO-d6) δ = 9.41 (d, J = 5.1, 2H), 9.00 ( d, J = 8.2, 2H), 8.76 ( d, J = 5.6, 1H), 8.33 ( s, 2H), 8.17 ( dd, J = 5.0, 8 .2,2H),8.07(t,J=7.7,1H),7.77(d,J=4.9,1H),7.68(d,J=7.9,1H),7.50(d,J=5.0,1H),7.34(t,J=6.6,1H).ESI-MS m / z:445.9958[M-CF3SO3 - ] + .
[0049] Example 3: Synthesis of Complex 2a
[0050] (1) Under a nitrogen atmosphere, palladium acetate and 2-(2-pyridyl)benzothiophene (pbt) were mixed in a molar ratio of 1:1 and dissolved in methanol to obtain solution A. Solution A was stirred at room temperature for 30 h. During the reaction, a yellow solid was precipitated. After the reaction was completed, the reaction solution was dried by rotary evaporation to obtain a yellow solid. The yellow solid was dissolved in a trace amount (1-2 ml) of CH2Cl2 and then hexane was added for precipitation. The solid was collected by solid-liquid separation. The solid was washed successively with hexane and diethyl ether and dried under vacuum at 50 °C to obtain a bright yellow palladium acetate bridged dimer [Pd(pd)OAc]2.
[0051] (2) Under a nitrogen atmosphere, [Pd(pbt)(OAc)]₂ (150 mg, 0.2 mmol) and lithium chloride (55.1 mg, 1.3 mmol) were dissolved in a mixture of acetone and ultrapure water (26 ml acetone, 10 ml water) to obtain solution B. Solution B was reacted at room temperature for 18 h, and the solid and liquid phases were separated. The solid was dried under vacuum to obtain a yellow palladium chloride bridged dimer [Pd(pbt)Cl]₂ (120 mg, 85.5%).
[0052] (3) Under a nitrogen atmosphere, palladium chloride bridged dimer [Pd(pbt)Cl]2 (120 mg, 0.17 mmol) and AgCF3SO3 (87.9 mg, 0.34 mmol) were dissolved in 15 ml of CH3CN solvent to obtain solution C. Solution C was reacted at room temperature for 32 h. The solid and liquid phases were separated, and the grayish-white AgCl precipitate was removed. The liquid phase was the intermediate product.
[0053] (4) Under a nitrogen atmosphere, 2,2'-bipyridine (bpy) (53.4 mg, 0.34 mmol) was added to the intermediate product, and the mixture was refluxed at 60 °C for 26 h. After the reaction was completed, the solid and liquid were separated, and the solid was washed successively with water and diethyl ether and dried at 60 °C to obtain a yellow solid complex 2a; the yield was 37.3%; the 1H NMR spectrum of complex 2a is shown in [reference needed]. Figure 1 High-resolution mass spectra can be found in [the image]. Figure 3 ;
[0054] The structural formula of the complex 2a is as follows: MRI 1 The H-spectrum and mass spectrometry data are as follows: 1 HNMR (600MHz, DMSO-d6) δ = 9.04 (d, J = 8.1, 1H), 8.69 (s, 2H), 8.57 (s, 1H), 8.45 (d, J = 5.6, 1H), 8.40 (d, J = 9.3, 1H), 8.31 (s, 1H), 8. 05–8.00(m,1H),7.95(s,1H),7.88(d,J=7.9,1H),7.83–7.75(m,1H),7.58(d,J=7.9,1H),7.47(s,1H),7.31(d,J=1.6,3H).ESI-MS m / z:417.9972[M-CF3SO3 - ] + .
[0055] Example 4: Synthesis of Complex 2b
[0056] Steps (1), (2), and (3) are the same as steps (1), (2), and (3) in Example 3;
[0057] Under a nitrogen atmosphere, 1,10-phenanthroline (phen) (61.6 mg, 0.34 mmol) was added to the intermediate product, and the mixture was refluxed at 60 °C for 30 h. After the reaction, the solid and liquid phases were separated, and the solid was washed successively with water and diethyl ether, and dried at 60 °C to obtain a yellow solid complex 2b; the yield was 45.6%. The 1H NMR spectrum of complex 2b is shown in [reference needed]. Figure 2 High-resolution mass spectra can be found in [the image]. Figure 4 ;
[0058] The structural formula of the complex 2b is as follows: MRI 1 The H-spectrum and mass spectrometry data are as follows: 1 H NMR (600MHz, DMSO-d6) δ = 8.91 (d, J = 8.4, 3H), 8.54 (t, J = 6.3, 3H), 8.29 (s, 3H), 8.02 (s, 2H), 7.88 (d,J=7.9,1H),7.66(s,1H),7.29(t,J=7.2,1H),7.22(t,J=7.3,1H),7.16(d,J=6.6,1H).ESI-MS m / z:496.0010[M-CF3SO3 - ] + .
[0059] Example 5: Synthesis of Complex 3a
[0060] (1) Under a nitrogen atmosphere, palladium acetate and 2-phenylthiazole (thpy) were mixed in a molar ratio of 1:1 and dissolved in ethanol to obtain solution A. Solution A was stirred at room temperature for 36 h. During the reaction, a yellow solid was precipitated. After the reaction was completed, the reaction solution was evaporated to dryness to obtain a yellow solid. The yellow solid was dissolved in a trace amount (1-2 ml) of CH2Cl2 and then hexane was added for precipitation. The solid was collected by solid-liquid separation. The solid was washed successively with hexane and diethyl ether and dried under vacuum at 50 °C to obtain a bright yellow palladium acetate bridged dimer [Pd(thpy)OAc]2.
[0061] (2) Under a nitrogen atmosphere, [Pd(thpy)OAc]2 (100 mg, 0.15 mmol) and lithium chloride (42.4 mg, 0.975 mmol) were dissolved in a mixture of acetone and ultrapure water (26 ml acetone, 10 ml water) to obtain solution B. Solution B was reacted at room temperature for 28 h, and the solid and liquid phases were separated. The solid was dried under vacuum to obtain a yellow palladium chloride bridged dimer [Pd(thpy)Cl]2 (60.4 mg, ...
[0062] 65.2%);
[0063] (3) Under a nitrogen atmosphere, palladium chloride bridged dimer [Pd(thpy)Cl]2 (60.4 mg, 0.12 mmol) and AgCF3SO3 (51.6 mg, 0.24 mmol) were dissolved in 15 ml of CH3CN solvent to obtain solution C. Solution C was reacted at room temperature for 32 h. The solid and liquid phases were separated, and the grayish-white AgCl precipitate was removed. The liquid phase was the intermediate product.
[0064] (4) Under a nitrogen atmosphere, 2,2'-bipyridine (bpy) (31.4 mg, 0.24 mmol) was added to the intermediate product, and the mixture was refluxed at 60 °C for 24 h. After the reaction was completed, the solid and liquid were separated, and the solid was washed with water and ether in sequence and dried at 60 °C to obtain a yellow solid complex 3a; the yield was 31.2%.
[0065] The structural formula of the complex 3a is as follows: MRI 1 The H-spectrum and mass spectrometry data are as follows: 1 HNMR (600MHz, DMSO-d6) δ=8.88(dd,J=1.6,5.7,1H),8.69(d,J=4.8,1H),8.65(d,J=8.0,1H),8.59(dd,J=3.7,8.6,1H),8.44–8.37 (m,2H),8.37–8.32(m,1H),8.17–8.10(m,1H),7.99–7.93(m,1H),7.84–7.74(m,3H),7.46(t,J=6.3,1H),7.24–7.13(m,1H).ESI-MS m / z:421.9957[M-CF3SO3 - ] + .
[0066] Example 6: Synthesis of Complex 3b
[0067] Steps (1), (2), and (3) are the same as steps (1), (2), and (3) in Example 5;
[0068] Under a nitrogen atmosphere, 1,10-phenanthroline (phen) (36.2 mg, 0.24 mmol) was added to the intermediate product, and the mixture was refluxed at 60 °C for 30 h. After the reaction was completed, the solid and liquid were separated, and the solid was washed with water and ether in sequence and dried at 60 °C to give a yellow solid complex 3b; the yield was 35.8%.
[0069] The structural formula of the complex 3b is as follows: MRI 1 The H-spectrum and mass spectrometry data are as follows: 1H NMR (600MHz, DMSO-d6) δ=9.33–9.27(m,2H),8.92(d,J=8.2,2H),8.32(d,J=3.5,1H),8.26(s,2H),8. 13–8.07(m,2H),7.95(d,J=3.5,1H),7.50–7.45(m,1H),7.36–7.30(m,1H),7.18–7.10(m,2H).ESI-MS m / z:445.9955[M-CF3SO3 - ] + .
[0070] Example 7: UV absorption and fluorescence emission of cyclic palladium(II) complexes in different solvents
[0071] 0.5 mg of each of the synthesized complexes in Examples 1-6 was weighed and added to dimethyl sulfoxide to prepare a 20 mmol / L stock solution. 3 μL of each stock solution was added to five 5 mL centrifuge tubes, and 27 μL of dimethyl sulfoxide was added. The solutions were then prepared to 20 μmol / L using PBS, H₂O, CH₃CN, CH₂Cl₂, and CHCl₃ (pH 7.0-7.4), respectively. The UV absorption was measured to obtain the UV absorption spectra. The fluorescence emission spectrum of complex 2a at an excitation light of 320 nm and an emission light of 359 nm was obtained. Figure 5 As shown in the figure, only CH3CN exhibits significant ultraviolet absorption (350-450 nm) and blue fluorescence emission.
[0072] Complex 2b exhibits a fluorescence emission spectrum at an excitation light of 320 nm and an emission light of 359 nm, as shown below. Figure 6 As shown, complex 2b exhibits UV absorption in CH3CN and strong fluorescence emission in CH2Cl2. Compared with complex 2a, complex 2b shows weaker UV absorption and corresponding fluorescence intensity in CH3CN, indicating that the increase of aromatic rings weakens the Pd-Pd interaction between molecules.
[0073] The detection results of complexes 1a, 1b, 2a, 2b, 3a, and 3b also showed that they all exhibited ultraviolet absorption and strong blue fluorescence emission (350-450nm) in CH3CN / CH2Cl2 / CHCl3 solution, but no such phenomenon was observed in H2O or PBS.
[0074] Example 8: Ion Selectivity Test of Cyclic Palladium(II) Complexes
[0075] Weigh 0.5 mg of each of the complexes from Examples 1-6 and add dimethyl sulfoxide to prepare a 20 mmol / L stock solution. Take 3 μL of the stock solution into a 5 mL centrifuge tube, add 27 μL of dimethyl sulfoxide, and dilute with water to 20 μmol / L. Add F to each solution. - Cl - ,Br - I - NO2 - NO3 - SO4 2- HSO3 - CO3 2- HCO3 - H2PO4 - CH3COO - ,ClO - ClO4 - The plasma, with a final ion concentration of 5 mmol / L, was used to measure the fluorescence spectrum of the above solution under 320 nm excitation light.
[0076] See results Figure 7 and 8 Complex 2a, with fewer aromatic rings and less steric hindrance, is effective against HSO3. - The complex 2b exhibits significant selectivity, but the ligand with a large aromatic ring hindrance shows weak selectivity for all ions. This indicates that for S-containing C^N ligands, increasing the number of aromatic rings in the bidentate N^N ligand will induce a weakening of intermolecular palladium-palladium interactions, thus reducing the selectivity for ions.
[0077] Example 9: Different complexes for HSO3 - Selective testing
[0078] Weigh 0.5 mg of complexes 1a-b, 2a-b, and 3a-b respectively, and prepare a 20 mmol / L stock solution in dimethyl sulfoxide. Add 3 μL of each stock solution to a centrifuge tube, add 27 μL of dimethyl sulfoxide, and then dilute with water to 20 μmol / L. Finally, add HSO3. - Ions, HSO3 - The final concentration was 5 mmol / L. The fluorescence of the above solution was measured under 320 nm excitation light to obtain the fluorescence spectrum, as shown below. Figure 9 As shown, complexes 1a-b and 3a-b affect HSO3 - It exhibits strong fluorescence responsiveness; simultaneously, given the same number of aromatic rings in the C^N ligands, the 2,2'-bipyridine complex with less steric hindrance in the N^N ligand shows better response to HSO3. - Overall, its fluorescence response is enhanced compared to that of 1,10-phenanthroline complexes.
[0079] Example 10: Solvent Effect of Complexes
[0080] 1 mg each of 1a, 1b, 2a, 2b, 3a, and 3b were weighed and added to dimethyl sulfoxide (DMSO) to prepare a 20 mmol / L solution. 3 μL of each solution was transferred to 5 mL centrifuge tubes, and 27 μL of DMSO was added to each tube. Then, H₂O, CH₃CN, CH₂Cl₂, CHCl₃, DMSO, Acetone, CH₃OH, THF, CH₃CH₂OH, C₆H₅CH₃, and Glycerol were added to prepare a 20 μmol / L solution. The fluorescence emission spectra were obtained under 320 nm excitation. The results are as follows: Figure 10-12 As shown, the left figure shows the complex with N^N ligand 2,2'-bipyridine, and the right figure shows the complex with N^N ligand 1,10-o-phenanthroline; all six cyclic metal Pd complexes showed strong blue fluorescence emission (350-450 nm) in THF and Glycerol solutions.
[0081] Example 11: Determination of the antitumor activity of cyclic metallized Pd(II) complexes
[0082] The cyclic metallized Pd(II) complexes prepared in Examples 1, 2, 3, 4, 5, and 6 were used as the experimental group and the complexes themselves, with cisplatin as the control group. Their cytotoxicity against HeLa (human cervical cancer cell line) was determined. The specific determination methods are as follows:
[0083] The MTT assay was used to determine the concentration of tumor cells. The tested tumor cells were digested with trypsin into single-cell suspensions, and cell counts were performed using a hemocytometer. The cell concentration was adjusted to 5 × 10⁻⁶ cells / mL. 4 / mL, seeded into 96-well plates, 160μL per well, and cultured for 24h. Then, different concentrations of the drug were added, and the plates were incubated in a 5% CO2 incubator at 37℃ for 48h. 4h before the end of incubation, 20μL of MTT was added per well. After 4h, the supernatant was discarded, and 150μL of DMSO was added per well. After shaking for 5min, the OD value was measured using a microplate reader at a wavelength of 492nm.
[0084] Calculate the survival rate of the tested tumor cells, plot the results, and determine the IC50. 50 The values were used to evaluate the antitumor activity of the complexes (see Table 1);
[0085] Table 1 IC of the cyclic metal Pd(II) complexes prepared in this invention 50 value
[0086]
[0087] The results indicate that the toxicity gradually increases with the increase of the number of aromatic rings in the N^N ligand of the complex, and the cytotoxicity of the complex with the C^N ligand being 2-(2-thiophene)pyridine is relatively high.
[0088] Example 12: Monitoring drug localization in tumor cells with different colored fluorescent dyes
[0089] HeLa (human cervical cancer cell line) cells in good growth condition were digested with trypsin and seeded into confocal culture dishes. The cells were cultured at 37°C in an incubator containing 5% CO2. When the HeLa cell density reached 70%, complex 2b was added to achieve a final drug incubation concentration of 20 μmol / L. After 24 h of further culture, appropriate concentrations of subcellular organelle fluorescent dyes (mitochondrial red fluorescent dye (MTDR, Ex=644nm, Em=665nm), lysosomal red fluorescent dye (LYDR, Ex=577nm, Em=590nm), and cell membrane far-infrared fluorescent dye (DID, Ex=644nm, Em=665nm)) were added for staining. After incubation for 10-15 min, the culture medium was removed, and the cells were washed twice with PBS. Immediate observation was performed using a laser confocal microscope. Results are shown in the figure below. Figure 14 Complex 2b was localized in lysosomes within the cell at 24 h.
[0090] Example 13: Bisulfite-induced self-assembly of cyclic metallized palladium complexes into nanoparticles
[0091] Weigh 0.5 mg of complexes 1a and 1b respectively, and prepare a 20 mmol / L stock solution in dimethyl sulfoxide. Add 3 μL of each stock solution to a centrifuge tube, add 27 μL of dimethyl sulfoxide, and then dilute with water to 20 μmol / L. Finally, add HSO3. - Ions, HSO3 - The final concentration was 5 mmol / L. Results were obtained by laser irradiation. Figure 11 The Tyndall effect can be observed when HSO3 is added. - Ions successfully induced the self-assembly of the prepared cyclic palladium complex into nanoparticles, and the average particle size varied with the amount of HSO3 in the solution. - The concentration gradually increases.
Claims
1. The application of cyclic palladium metallized complexes as fluorescent probes in the preparation of reagents for detecting bisulfite, characterized in that: The structural formula of the cyclic palladium metallide complex is: , , , or .
2. The application of cyclic palladium metallized complexes in the preparation of cell diagnostic and imaging reagents, characterized in that: The structural formula of the cyclic palladium metallide complex is as follows: .
3. The application of cyclic palladium metallized complexes in the preparation of antitumor drugs, characterized in that: The structural formula of the cyclic palladium metallide complex is as follows: .