A Novel Mononuclear Copper(Ⅱ) Complex:Crystal Structure and DNA Cleavage Ability

The reaction of N-tosylatirdine with 1,2-diaminopropane in dry benzene solution yields an intermediate H2L, N,N,N＇,N＇-tetrakis（2-（p-tolylsulfonyl）aminoethyl） propane-1,2-diamine. The mononuclear copper（Ⅱ） complex, [CuLH2O]·H2O, was synthesized by the reaction between the intermediate and copper（Ⅱ） in absolute methanol. The complex has been characterized by IR, UV-vis and X-ray diffraction technology, and its crystal crystallizes in the orthorhombic system, space group Pbca with a = 15.589（1）, b = 21.897（2）, c = 27.645（2） A, V = 9436.4（1）A^3, Dc = 1.352 g/cm^3, Z = 8, Mr = 960.68, F（000） = 4040, μ（MoKa） = 0.698 mm-1, S = 0.98, R = 0.0537 and wR = 0.1180 for 5804 observed reflections （I 〉 2σ（I））. In the crystal structure, a one-dimensional chain is formed by abundant hydrogen bond interactions. The interaction of the complex with DNA was monitored using agarose gel electrophoresis. The result shows that the complex can transform the supercoiled to nicked and liner forms, and has a concentration-dependent cleavage activity.

Efficient DNA Cleavage by Copper(Ⅱ) Complex Derived from 1, 1′-Dimethyl-2, 2′-biimidazole Ligand

The cleavage of DNA （pBR322） by [Cu（Dime-biim）2（H2O）]（ClO4）2 （Dime-biim=1, 1＇- dimethyl-2, 2＇-biimidazole） was investigated. The results showed that the complex could cleave DNA efficiently at pH=8.0 and 37℃.

Cleavage of DNA by a New Mixed-ligand Cu(Ⅱ) Complex

Cleavage of DNA pUC19 by [Cu(saldien)(NH3)]Cl2 (here, saldien=bis(salicylicdene)- diethylenetriamine) was investigated at different pHs, times, concentrations, and 37℃. It was found that the copper(Ⅱ) complex could cleave DNA without added coreactants.

Synthesis and Crystal Structure of a Dinuclear Cu(Ⅱ) Complex Based on a Carboxyl-substituted 1H-1,2,3-Triazole and Its DNA Cleavage Activity

The novel dinuclear copper complex [Cu2（H20）2（DMF）2（L）2] （1, H2L = 5-phenyl- 2H-1,2,3-triazole-4-carboxylic acid, DMF = N,N-dimethyl-formamide） has been synthesized and characterized by X-ray single-crystal diffraction. The compound crystallizes in triclinic system, space group P1 with a = 9.591, b = 10.508, c = 15.515A,β = 75.11°, V= 1446.2 A3, Z= 2, Mr = 683.62, Dc = 1.570 g/cm3, μ = 1.531 mm^-1, F（000） = 700, the final R = 0.0404 and wR = 0.1130 for 5327 observed reflections with I 〉 2σ（I）. In each unit of the complex, two Cu2＋ ions coordinated with two triazole ligands to form a dimeric [5,6,5] tricyclic structure. The central Cu atom is five-coordinated, and each copper atom shows a square pyramidal geometry. The crystal structure is stabilized by the inversion-related O-H…O hydrogen bond and C-H…O hydrogen bonding interactions to form a layer structure. Fluorescent spectra show an obvious quenching of fluorescence compared with free 1,2,3-triazole ligand. The results of agarose gel electrophoresis indicate that this complex can cleave the plasmid supercoiled DNA within shorter time in the 50-folds excess of ascorbate under physiological conditions, providing a new example in the research for artificial metal nucleic acid enzyme.

Synthesis, structure, DNA binding and cleavage activity of a new copper(II) complex of bispyridylpyrrolide

A copper-bispyridylpyrrolide complex [Cu(PDPH)Cl](PDPH = 2,5-bis(2′-pyridyl)pyrrole) was synthesized and characterized. The complex crystallizes in the orthorhombic system with space group Pccn, a = 0.9016(3) nm, b = 1.0931(4) nm, c =2.5319(8) nm, and V = 2.4951(15) nm3. The copper center is situated in a square planar geometry. The interaction of the copper(II)complex with calf thymus DNA(CT-DNA) was investigated by electronic absorption, circular dichroism(CD) and fluorescence spectra. It is proposed that the complex binds to CT-DNA through groove binding mode. Nuclease activity of the complex was also studied by gel electrophoresis method. The complex can efficiently cleave supercoiled p BR322 DNA in the presence of ascorbate(H2A) via oxidative pathway. The preliminary mechanism of DNA cleavage by the complex with different inhibiting reagents indicates that the hydroxyl radicals were involved as the active species in the DNA cleavage process.

Rapid, Catalytic Hydrolysis of DNA by Copper(Ⅱ) Complexes

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Efficient Cleavage of DNA by the Novel Copper (II) Complex Derived From 2,2'-Pyridil Ligand

Copper (II) complex derived from 2, 2'-pyridil ligand has been, demonstrated to cleave efficiently DNA at micromolar concentrations at room temperature and pH 7.25.

Synthesis,Crystal Structure and DNA-binding Properties of a New Copper(Ⅱ) Schiff Base Complex

A new asymmetric bidentate copper（Ⅱ） complex,CuL 2（HL=2-（（E）-（4-bromophenylimino）methyl）-6-bromo-4-chlorophenol）,has been synthesized and characterized by elemental analyses and single-crystal X-ray diffraction.The complex crystallizes in the monoclinic space group P2 1 /c with a=11.218（3）,b=9.355（3）,c=13.449（4）,β=108.722（4）°,V=1336.8（6）3,Z=2,Dc=2.008 g/cm 3,μ（MoKα）=7.024 mm-1,F（000）=806,S=0.999,the final R=0.0342 and wR=0.0641for2611observed reflections （I〉2σ（I））.The central copper（Ⅱ） is four-coordinate and bonds to two nitrogen and two oxygen atoms from two Schiff base ligands.The complex is linked into a two-dimensional supramolecular structure by weak intermolecular interactions.In addition,DNA-binding properties of the metal complex were investigated using spectrometric titrations and viscosity measurements.The results show that the complex binds with calf-thymus DNA（CT-DNA）,presumably via a partial intercalative mode.The intrinsic binding constant of the Cu（Ⅱ） complex with DNA is 7.335×10 3 M-1.

Electrochemical and Spectroscopic Studies on Interaction between Complex of Copper(Ⅱ) with Schiff Base Ligand and DNA

The crystal structure of ([CuL(H_2O)_2](ClO_4)_2·2H_2O, CuL)(L=N-(5-sulfosalicylidene)-4′-bromoaniline) was determined by means of X-ray crystallography. The interaction between CuL and salmon sperm DNA in a 0.1 mol/L HOAc-NaOAc buffer solution(pH 5.10) was investigated by cyclic voltammetry and UV-Vis spectroscopy. A couple of redox peaks of CuL in the cyclic voltammograms(CV) can be seen at the glassy carbon electrode. It was found that the peak current of CuL decreased significantly with a negative shift of the peak potential in the presence of DNA compared with that in the absence of DNA. In addition, the decreased absorbance of CuL was observed with increasing the concentration of DNA; the absorption spectrum of an ethidium bromide(EB)-DNA system in the presence of CuL confirms that the binding mode of CuL to DNA is different from the intercalation of EB with DNA. All the experimental results indicate that CuL can bind to DNA by electrostatic binding and form a 1∶1 association complex with a binding constant of 2.72×10 4 L/mol.

Synthesis,Characterization,and DNA Binding Properties of Dinuclear Copper(Ⅱ) Complex [Cu_2(TATP)_2(L-Leu)_2(ClO_4)_2]_2·2H_2O

A dinuclear copper（Ⅱ） complex[Cu2（TATP）2（L-Leu）2（CIO4）2]2·2H2Owas synthesized and characterized, where, TATP=1,4,8,9-tetraazatriphenylene, and L-Leu=L-leucinate. The complex was crystallized in the triclinic space group P1, with two independent molecules in a unit cell. Two Cu（Ⅱ） ions in each complex [Cu2（TATP）2（L-Leu）2（CIO4）2] molecule were found to be in different coordination geometries, i.e., Cu2 or Cu4 of a distorted square-pyramidal geometry coordinated with two nitrogens of TATP, the amino nitrogen and one carboxylate oxygen of L-Leu and one oxygen of perchlorate, and Cul or Cu3 with an octahedral geometry coordinated with the above stated similar coordinated atoms, and another carboxylate oxygen of L-Leu coordinating to Cu2 or Cu4. The complex can interact with CT-DNA by an intercalative mode and cleave pBR322 DNA in the presence of ascorbate.

DNA Cleavage by Copper (Ⅱ) Complexes Without added Coreactants

The cleavage activity of complexes between copper (Ⅱ) and four different amino acidor amino acid methyl ester on DNA was tested at physioloical pH and temperature., It was found that Cu (Ⅱ)-L-His and Cu (Ⅱ)-L-His methyl ester complexes could cleane DNA. The extent ofDNA cleavage is largely dependent on the metal ion-to-ligand ratio. The cleavage of doublestranded DNA mediated by Cu (Ⅱ)-L-His complexes occurs via a hydrolytie mechanism.

DNA Cleavage of the Copper(II) Complexes with a Polyamine Ditopic Ligand

A new binuclear complex [Cu2L(OH)](ClO4)3·2H2O has been synthesized and characterized, where L=2,6-bis{[bis-(2-aminoethyl)amino]methyl}-benzene. In the presence of 0.5 mmol/L complex at pH 8.10 and 37°C, the complex can efficiently cleavage pBR322 DNA with a rate constant kobs of 1.35×10-4 s-1. The cleavage occurred by a non-oxidative mechanism showing activity to be dependent on pH.

Electrochemical and Spectroscopic Studies on the Interaction between Tetracoordinate Macrocyclic Copper（Ⅱ）, Nickel（Ⅱ） and Cobalt（Ⅲ） Complexes with DNA

Mononuclear copper（Ⅱ）, nickel（Ⅱ） and cobalt（Ⅲ） tetracoordinate macrocyclic complexes were synthesized and spectroscopically characterized. The crystal structure of the three compounds were determined by X-ray crystallography. The electrochemical experimental results indicate that the three complexes could interact with DNA mainly by electrostatic interaction. The interaction of tetracoordinate macrocyclic cobalt（Ⅲ） complex with DNA was studied by cyclic voltammetry and UV-vis spectroscopy. The experimental results reveal that tetracoordinate macrocyc- lic cobalt（Ⅲ） complex could interact with DNA by electrostatic interaction to form a 1 ： 1 DNA association complex with a binding constant of 7.50 ×10^3 L·mol^-1.

三核铜配合物[Cu_3L_2](ClO_4)_2(H_2L=1,3-双(2-羟基-1-苯基-亚甲基)-丙烷)的合成与对pBR322 DNA的切断作用

利用席夫碱配体 [H2 L =1,3 双 (2 羟基 1 苯基 -亚甲基 ) -丙烷 ]与铜盐作用 ,得到了配合物 [Cu3 L2 ] (ClO4) 2 ,并用X射线单晶衍射测定了其晶体结构 .研究了该三核铜配合物与质粒pBR3 2 2DNA之间的相互作用 ,琼脂糖凝胶电泳实验结果表明该配合物能够将pBR3 2 2DNA从超螺旋构型切割成开环型和线型 .同时 ,紫外光谱实验可以推测 ,配合物在对pBR3 2 2DNA进行切断时 。

Studies of copper (Ⅱ) complexes as catalysts for the hydrolysis of DNA

Hydrolysis of DNA is an important enzymatic reaction , but it is exceedingly difficult to mimic in the laboratory because of the stability of hydrolysis of DNA. In this paper, the cleavage activity of complexes formed between Cu(Ⅱ) and four different amino acid or amino acid methyl ester on DNA is studied by gel elec-trophoresis. It is found that DNA could be cleaved by Cu(Ⅱ)-L-His and Cu(Ⅱ)-L-His methyl ester complexes and the efficiency of cleavage is largely dependent on the metal ion-to-ligand ratio. Further experiments show that the cleavage of DNA mediated by Cu(Ⅱ)-L-His complexes occurs via a hydrolytic mechanism and the active chemical species that affects DNA cleavage is proposed to be MI2H+ and ML2H22+.

Characterization, Crystal Structure and Initial DNA Binding Interaction of Two Cu（Ⅱ） Complexes with 4,5-Diazafluoren-9-one

Two new complexes [Cu（dafo）2（en）]（ClO4）2·2H2O （en=NH2CH2CH2NH2） 1 and [Cu（dafo）2（dap）]（ClO4）2·2H2O [dap=NH2CH2CH（CH3）NH2] 2 （dafo=4,5-diazafluoren-9-one） have been synthesized and characterized by elemental analysis, IR and UV spectra. Meanwhile, the complex 1 has been characterized by single crystal X-ray diffraction analysis. The initial DNA binding interactions of the complexes 1 and 2 have been investigated by UV spectra, emission spectra and cyclic voltammogram. Concluding the results of three methods used to measure the interaction of complexes 1 and 2 with DNA, the action mode of the two complexes with DNA is intercalation, and character of ligands and steric effect may affect the interaction of the complexes with DNA.

Mass spectrometry assisted assignments of binding and cleavage sites of Zn(Ⅱ)complex towards oxidized insulin B chain

The electrospray ionization mass spectrometry investigation showed that the binding sites of [ZnL]^2＋, where L is 2-[bis（2- aminoethyl）amino]ethanol, with oxidized insulin B chain are Phel, His5 and Arg22, which lead to the selective cleavages of the peptide bonds at Phe1-Val2, His5-Leu6, Glu21-Arg22, and Arg22-Gly23 of oxidized insulin B chain.

A Novel Copper(Ⅱ) Complex of Asymmetrically N-Functionalized 1,4,7-Triazacyclononane Ligand： Syntheses, Structure, Electrochemical Property and Biological Activities

A novel copper（Ⅱ） complex derived from 1,4,7-triazacyclononane[CuL]_2（PF_6）_3×MeCN×H_2 O was synthesized and crystallographically characterized {L = 1,4-bis（2-carbamoylethyl）-7-benzimidazole-2-yl-methyl-1,4,7-triazacyclononane}. It crystallizes in triclinic, space group P1, with a = 13.2425（13）, b = 14.0807（15）, c = 17.6798（18）, α = 86.296（2）, β = 72.773（2）, γ= 68.905（2）o, V = 2934.5（5）A^3, Z = 2, D_c = 1.611 g/m^3, F（000） = 1456, M_r = 1423.09, m = 0.920 mm^-1. The final R = 0.0671 and wR = 0.1874 for 6501 observed reflections with I 〉 2σ（I）. The structural analysis shows that the complex cation（[CuL]_2^3＋） was formed by two complex cations, namely（[CuL^3]^2＋） and [CuL_（-H）~3]~＋） through a hydrogen bond. In each complex cation, the Cu（Ⅱ） lies in a distorted square pyramidal geometry. The redox behavior was studied by cyclic voltammetry（CV） in aqueous solution which indicates a reversible one electron redox reaction. The result of UV absorption, ethidium bromide（EB） fluorescence spectra indicated that the complex binds to CT-DNA in an intercalative mode. Superoxide dismutase（SOD） activity of the complex was determined by photoreduction of NBT, and the value of IC_（50） is 5.22 μmol·L^-1.

铜(Ⅱ)邻菲咯啉蛋氨酸配合物与DNA相互作用的研究

在pH =6 86磷酸盐缓冲溶液中 ,采用电化学 (循环伏安法、微分脉冲伏安法和交流阻抗及数据拟合技术 )、粘度测定、电子吸收光谱和溴化乙锭 (EB)荧光分析法研究了 [Cu(phen) (H2 O) (L Met) ] + (phen =1,10 邻菲咯啉 ,L Met =L 蛋氨酸 )与小牛胸腺DNA的相互作用 .结果发现中心铜离子在循环伏安图上呈现 1对明显的准可逆氧化还原波 .当加入一定量的DNA时 ,配合物的氧化还原峰电流明显降低 ,扩散系数减小 ,电化学反应电阻增大 ,电子光谱的最大吸收峰明显红移 ,产生明显的减色效应 ,同时 ,配合物也能较大程度地猝灭EB DNA体系的荧光 ,说明 [Cu(phen) (H2 O) (L Met) ] + 与DNA的作用较强 。

钌(Ⅱ)多吡啶配合物与DNA相互作用研究

DNA是遗传信息的携带者和基因表达的物质基础,金属配合物与DNA的相互作用研究已受到广泛关注,成为生物无机化学的重要研究内容之一。本文简要评述了钌(Ⅱ)多吡啶配合物在DNA识别、断裂及拓扑异构酶抑制方面的研究情况。