芬布芬-铜（Ⅱ）-牛血清白蛋白相互作用的光谱法研究

模拟生理条件下,应用荧光光谱法研究了芬布芬对牛血清白蛋白,铜（Ⅱ）对牛血清白蛋白以及铜（Ⅱ）对芬布芬和牛血清白蛋白荧光光谱特性的影响.实验表明：铜（Ⅱ）和芬布芬均可使牛血清白蛋白的荧光强度发生静态猝灭,并且在铜（Ⅱ）存在下,芬布芬对牛血清白蛋白的荧光猝灭作用显著增强.根据荧光猝灭双倒数图计算芬布芬和牛血清白蛋白的结合常数为8.44×104,结合位点数为0.97.荧光猝灭双倒数图计算的结果表明,芬布芬和牛血清白蛋白之间的结合常数和结合位点数均随铜（Ⅱ）浓度的增大而增大.很据三者结合反应的研究,进一步探讨了芬布芬、铜（Ⅱ）在生物体内与蛋白质相互作用的机理.     

光谱法研究α-萘乙酸与核酸的相互作用

利用荧光光谱法研究了α-萘乙酸（NAA）与DNA之间的相互作用。结果表明,DNA能使NAA的荧光强度猝灭,根据荧光强度变化和荧光猝灭公式求得NAA与DNA的荧光猝灭常数。荧光寿命实验结果表明,荧光猝灭是由形成复合物的静态猝灭过程所致。黏度实验、离子强度实验等多种实验结果表明,NAA与DNA间的结合作用为部分插入式和沟槽式相结合。     

铽-环丙沙星与罗丹明B间稀土敏化荧光能量转移机理研究

利用荧光光谱法及紫外光谱法研究发现pH6.2醋酸-醋酸钠(HAc-NaAc)水溶液中铽与环丙沙星形成络合物使铽在490,545,590nm处出现Tb3 的特征发射峰即荧光被强烈的敏化增强,且在545nm处的荧光强度最大,铽离子的锐线发射光谱的特征最强峰545nm与罗丹明B的最大吸收峰波长552nm十分接近,能够发生能量转移反应。因此,随着碱性染料罗丹明B的加入铽-环丙沙星的特征荧光呈现有规律降低,表明罗丹明B对铽-环丙沙星荧光有猝灭作用,研究结果表明其猝灭类型主要为静态猝灭。又根据Frster理论,测得了罗丹明B对铽-环丙沙星的能量转移效率,相互结合距离等参数。从而进一步证明了该反应是单一静态猝灭过程,阐述了其荧光猝灭机理是通过能量转移产生的。     

荧光光谱法研究Hg（Ⅱ）与牛血清白蛋白的相互作用

在pH为7.15、离子强度为0.15mol/L的NaCl溶液条件下,采用荧光光谱法研究了Hg（Ⅱ）与牛血清白蛋白的相互作用。实验结果表明,Hg（Ⅱ）对牛血清白蛋白的荧光强度猝灭机理是一种静态猝灭,且Hg2＋与牛血清白蛋白结合的位点数为2,表观络合常数（K）为2.468×10^10L^2·mol^-2。     

大黄素-铜（Ⅱ）配合物与核酸的相互作用

用光谱法研究了大黄素-铜（Ⅱ）配合物与核酸相互作用。在pH=5.6时和最大发射波长434nm处,核酸能显著地猝灭大黄素-铜（Ⅱ）的荧光强度。在最佳条件下,对ctDNA和yRNA的线性范围分别是0.18—2.2μg/mL和0.16—2.3μg/mL。通过合成试样实验,结果令人满意。     

邻菲绕啉对Tb（Ⅲ）、Eu（Ⅲ）水杨酸二元配合物荧光强度的影响研究

通过分析邻菲绕啉与Ｔｂ（Ⅱ）、Ｅｕ（Ⅱ）水杨酸二元、三元配合物的多种谱留数据、证实由于邻菲绕啉的最低三重态与Ｔｂ（Ⅱ）、Ｅｕ（Ⅱ）离子的第一激发态能级差的不同，使得邻菲绕啉够增强Ｅｕ（Ⅱ）离子的水杨酸二元配合物的荧光强度而减弱Ｔｂ（Ⅱ）离子的水杨酸二元配合物的荧光强度．     

Mn（Ⅱ）与BSA相互作用的热力学特征

运用荧光光谱法研究了锰（Ⅱ,Mn2＋）与牛血清白蛋白（Bovine Serum Albumin,BSA）的相互作用.随着Mn2＋浓度的增大,BSA的荧光强度降低,最大发射峰蓝移2nm,根据Stern-Volmer方程求出了Mn2＋与BSA作用的猝灭常数,其猝灭机制为静态猝灭.根据热力学方程求得了290K和308K时的热力学参数△H、△G和△S,结果表明温度升高Mn2＋与BSA的作用增强,二者之间的作用力主要为疏水作用和静电作用.     

氧化石墨烯如何猝灭罗丹明6G的荧光

考察了水相溶液中氧化石墨烯对罗丹明6G的高效荧光猝灭．借助稳态及时间分辨荧光光谱测量,结合对该二元体系线性吸收谱变化的细致分析,澄清了相关荧光猝灭机理,即动态猝灭与静态猝灭的联合猝灭机制．提出在静态猝灭过程中罗丹明6G与氧化石墨烯所形成的可能的基态复合物,并进一步讨论了二者之间的光致电子转移过程．     

荧光探针技术研究阿特拉津与ct-DNA的相互作用

利用分子荧光探针和紫外吸收光谱技术研究了阿特拉津（Atrazine）与小牛胸腺DNA（ct-DNA）之间的相互作用。实验中选用溴化乙锭（EB）为荧光探针,考察了阿特拉津浓度、磷酸盐、离子强度以及碘化钾对系统荧光的影响。结果表明,阿特拉津对ct-DNA-EB体系的荧光存在猝灭现象,并同时存在静态和动态两种猝灭方式。KI对ct-DNA-Atrazine体系的荧光猝灭及阿特拉津使ct-DNA紫外吸收的增色和红移现象表明阿特拉津与ct-DNA之间存在嵌插作用。磷酸盐、离子强度对ct-DNA-EB-Atrazine体系的荧光强度影响表明,阿特拉津与ct-DNA的磷酸基之间存在非特征性的静电作用,并且高离子强度不利于这种作用。     

铕和铽对四（3,4-亚甲二氧基苯基）卟啉的荧光猝灭

通过荧光光谱法研究了铕（Ⅲ）、铽（Ⅲ）两种稀土离子对四（3,4-亚甲二氧基苯基）卟啉（TMPP）荧光强度的影响.在中性介质中,铕（Ⅲ）和铽（Ⅲ）与TMPP相互作用使TMPP的荧光猝灭.实验表明：以DMF为溶剂、420 nm为最大激发波长、655nm为最大发射波长时,TMPP的荧光强度和稀土离子对其荧光猝灭均达到最大值.     

铜(Ⅱ)配合物与DNA作用的光谱法研究

采用紫外光谱和荧光光谱研究了配离子[Cu(A)₂]2＋(其中A=邻菲络啉(phen),联吡啶(bpy),乙二胺(en))与小牛胸腺DNA的相互作用。实验发现配合物的存在使DNA碱变性的pH增大,变性后增色效应减小。EB-DNA体系的荧光强度随[Cu(phen)₂]2＋的加入迅速减弱。在DNA存在下,配离子被猝灭剂[Fe(CN)₆]4-的发光猝灭程度减小。进一步研究了配体分子平面的大小对配合物与DNA作用的影响。结果表明,铜配合物与DNA之间发生了插入作用,且该作用随配体芳环平面的减小而减弱, 即[Cu(phen)₂]2＋＞[Cu(bpy)₂]2＋＞[Cu(en)₂]2＋。     

Synthesis,Characterization, DNA Binding Properties,Fluorescence Studies and Antioxidant Activity of Transition Metal Complexes with Hesperetin-2-hydroxy Benzoyl Hydrazone

A novel Schiff-base ligand (H₅L), hesperetin-2-hydroxy benzoyl hydrazone, and its copper (II), zinc (II) and nickel (II) complexes (M·H₃L) [M(II) = Cu, Zn, Ni], have been synthesized and characterized. The ligand and Zn (II) complex exhibit green and blue fluorescence under UV light and the fluorescent properties of the ligand and Zn (II) complex in solid state and different solutions were investigated. In addition, DNA binding properties of the ligand and its metal complexes have been investigated by electronic absorption spectroscopy, fluorescence spectra, ethidium bromide displacement experiments, iodide quenching experiments, salt effect and viscosity measurements. Results suggest that all the compounds bind to DNA via an intercalation binding mode. Furthermore, the antioxidant activity of the ligand and its metal complexes was determined by superoxide and hydroxyl radical scavenging methods in vitro. The metal complexes were found to possess potent antioxidant activity and be better than the free ligand alone and some standard antioxidants like vitamin C and mannitol.     

金属-糖胺配合物的合成,光谱表征及催化酯类水解的动力学研究

合成了4种新的糖胺 金属配合物,分别为[Ni(HL) (H2 O) 2 ]2 Cl2 ·CH3OH·2H2 O ,[Cu(HL) ]2 Cl2 ·CH3CH2 OH·3H2 O ,[Zn(HL) ]2 Cl2 ·H2 O ,[Co(HL) (H2 O) (OH) ]2 Cl2 ·CH3OH·2H2 O (HLN ,N′ 二βD 葡萄糖基乙二胺) ,并用元素分析、红外、紫外、核磁共振氢谱对其结构进行了表征。结果表明,Ni(Ⅱ) ,Co(Ⅲ)配合物为八面体构型,而Cu(Ⅱ) ,Zn(Ⅱ)配合物为四面体构型。最后研究了其对对硝基苯吡啶甲酸酯(PNPP)催化水解的催化速率常数。     

EPR Studies of DOPA–Melanin Complexes with Netilmicin and Cu(II) at Temperatures in the Range of 105–300?K

The application of electron paramagnetic resonance (EPR) spectroscopy in pharmacy of melanin complexes with netilmicin and Cu(II) was presented. The continuous microwave saturation of EPR spectra of DOPA–melanin and the complexes was performed. EPR spectra were measured on an X-band (9.3?GHz) spectrometer at temperatures in the range of 105–300?K. Paramagnetic copper ions decrease the intensity of the EPR lines of melanin’s free radicals. It was found that fast spin–lattice relaxation characterizes DOPA–melanin–Cu(II) complexes. Slow spin–lattice relaxation processes exist in melanin’s paramagnetic centers of DOPA–melanin and DOPA–melanin–netilmicin, [DOPA–melanin–netilmicin]–Cu(II), [DOPA–melanin–Cu(II)]–netilmicin complexes. Spin–lattice relaxation processes are faster at higher temperatures. The homogeneous broadening of EPR lines for melanin complexes was observed. The practical consequences of differences between paramagnetic properties of melanin complexes with netilmicin and the complexes with Cu(II) were discussed.     

Synthesis,Spectral Characterization,DNA/ Protein Binding,DNA Cleavage,Cytotoxicity, Antioxidative and Molecular Docking Studies of Cu(II)Complexes Containing Schiff Base-bpy/Phen Ligands

Ternary Cu(II) complexes [Cu(II)(L)(bpy)Cl] 1, [Cu(II)(L)(Phen)Cl] 2 [L = 2,3–dimethyl-1-phenyl-4(2 hydroxy-5-methyl benzylideneamino)-pyrazol-5-one, bpy = 2,2^′ bipyridine, phen =1,10 phenanthroline) were synthesized and characterized by elemental analyses, UV-Visible, FT-IR, ESR, Mass, thermogravimetric and SEM EDAX techniques. The complexes exhibit octahedral geometry. The interaction of the Cu(II) with cailf thymus DNA (CT-DNA) was explored by using absorption and fluorescence spectroscopic methods. The results revealed that the complexes have an affinity constant for DNA in the order of 10⁴ M^?1 and mode of interaction is intercalative mode. The DNA cleavage study showed that the complexes cleaved DNA without any external agent. The interaction of Cu(II) complexes with bovine serum albumin (BSA) was also studied using absorption and fluorescence techniques. The cytotoxic activity of the Cu(II) complexes was probed in HeLa (human breast adenocarcinoma cell line), B16F10 (Murine melanoma cell line) and HEPA1–6 celllines, complex 1 has good cytotoxic activity which is comparable with the doxarubicin drug, with IC₅₀ values ranging from 3 to 12.6 μM. A further molecular docking technique was employed to understand the binding of the complexes towards the molecular target DNA. Investigation of the antioxidative properties showed that the metal complexes have significant radical scavenging activity potency against DPPH radical.     

Raman and SERS study on cimetidine–metal complexes with biomedical interest

Cimetidine (cim) is one of the most potent histamine H₂‐receptor antagonists for inhibiting excessive acid secretion caused by histamine; it has been hypothesized that the therapeutic effects can be related to its interactions with metal ions. Raman spectra of the solid cim with Co(II), Cu(II), Ni(II) and Zn(II) metal complexes show that they can adopt two different structures: one is octahedral and the other, with Zn(II), is probably tetrahedral. The octahedral structure appears to be distorted both by the different metal ions as well as by the different anion present. The study was extended to very dilute solutions (ppm range) by using the surface‐enhanced Raman scattering (SERS) technique, mimicking the physiological concentrations of cim and its metal complexes. SERS spectra suggest that, upon the binding of cim to silver colloids, the formation of stable 1:2 cim–metal complexes is excluded, the formation of 1:1 adduct appearing more probable; in this product the metal reaches its total coordination shell by complexion with water molecules. To better explain the binding mechanism of cim to a metal (Ag) surface, we performed theoretical B3LYP calculations on cim alone as well as on cim bonded to an Ag₂ metal cluster in presence of water, observing a sufficiently good agreement between experimental and theoretical wavenumbers. Copyright © 2010 John Wiley & Sons, Ltd.     

Spectro Analytical,Computational and In Vitro Biological Studies of Novel Substituted Quinolone Hydrazone and it’s Metal Complexes

Some novel transition metal [Cu (II), Ni (II) and Co (II)] complexes of nalidixic acid hydrazone have been prepared and characterized by employing spectro-analytical techniques viz: elemental analysis, ¹H-NMR, Mass, UV–Vis, IR, TGA-DTA, SEM-EDX, ESR and Spectrophotometry studies. The HyperChem 7.5 software was used for geometry optimization of title compound in its molecular and ionic forms. Quantum mechanical parameters, contour maps of highest occupied molecular orbitals (HOMO) and lowest unoccupied molecular orbitals (LUMO) and corresponding binding energy values were computed using semi empirical single point PM3 method. The stoichiometric equilibrium studies of metal complexes carried out spectrophotometrically using Job’s continuous variation and mole ratio methods inferred formation of 1:2 (ML₂) metal complexes in respective systems. The title compound and its metal complexes screened for antibacterial and antifungal properties, exemplified improved activity in metal complexes. The studies of nuclease activity for the cleavage of CT- DNA and MTT assay for in vitro cytotoxic properties involving metal complexes exhibited high activity. In addition, the DNA binding properties of Cu (II), Ni (II) and Co (II) complexes investigated by electronic absorption and fluorescence measurements revealed their good binding ability and commended agreement of K_b values obtained from both the techniques. Molecular docking studies were also performed to find the binding affinity of synthesized compounds with DNA (PDB ID: 1N37) and “Thymidine phosphorylase from E.coli” (PDB ID: 4EAF) protein targets.     

Synthesis of 1,8–Naphthyridines and Their Application in the Development of Anionic Fluorogenic Chemosensors

Two 1,8-naphthyridines were synthesized and found to be fluorescent in solution. These compounds were studied in the presence of Cu(+) and Cu(2+) ions and it was verified that the metal causes the quenching of their fluorescence emission, due to the formation of complexes between the naphthyridine and the metal. A displacement assay was carried out in a DMSO-water mixture with the addition of various anions to the solutions of the complexes, and it was observed that these systems have a high capacity to selectively detect cyanide.     

卟啉配合物-巯基棉体系分光光度法测定中药中铅、镉、铜

研究了卟啉与铅、镉、铜的反应及配合物的电子吸收光谱。结合巯基棉分离富集方法 ,将此金属卟啉配合物体系成功地应用于中药中微量铅、镉、铜的测定。方法简便 ,测定体系抗干扰的效果好 ,灵敏度高。实际样品测定的RSD在 3 3%～ 9 6 %之间。样品加标回收率在 90 %～ 1 0 3%之间。     

Inert and stable erbium(III)-cored complexes based on metalloporphyrins bearing aryl-ether dendron for optical amplification: synthesis and emission enhancement

We have developed novel inert and stable erbium (Er)(III)-cored complexes based on metalloporphyrins for optical amplification. The functionalized metalloporphyrin ligands have been designed and synthesized to provide enough coordination sites for the formation of inert and stable 9-coordinated Er(III)-cored complexes. Er³⁺ ions were encapsulated by the metalloporphyrin ligands, such as Zn(II)- and Pt(II)-porphyrins. The near-infrared (IR) emission intensity of Er³⁺ ion is much stronger in the Er(III)-cored complex based on Pt(II)-porphyrin than Er(III)-cored complex based on Zn(II)-porphyrin. Furthermore, we have incorporated a G2-aryl-ether functionalized dendron into the Er(III)-cored complex, yielding an Er(III)-cored dendrimer complex bearing the Pt(II)-porphyrin. The Er(III)-cored dendrimer complex shows the stronger near-IR emission intensity than the corresponding complex based on Pt(II)-porphyrin by seven times in solid state. The lifetimes of the emission band of Pt(II)-porphyrin ligands in the visible region were found to be 30 and 40 μs for the Er(III)-cored complex and the Er(III)-cored dendrimer complex based on Pt(II)-porphyrin in deoxygenated THF solution samples, respectively. Also, in both cases, the sensitized luminescence intensity is increased in deoxygenated solution. Therefore, it indicates that the energy transfer from the metalloporphyrins to Er³⁺ ions takes places through the triplet state. In this paper, the synthesis and photophysical properties of novel Er(III)-cored complexes based on metalloporphyrins and Er(III)-cored dendrimer complex based on metalloporphyrin will be discussed.