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首页> 外文期刊>Polyhedron: The International Journal for Inorganic and Organometallic Chemistry >Synthesis, structural characterization and potentiometric studies of divalent metal complexes with an octadentate tetraazamacrocyclic ligand and their DNA cleavage ability
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Synthesis, structural characterization and potentiometric studies of divalent metal complexes with an octadentate tetraazamacrocyclic ligand and their DNA cleavage ability

机译：具有八齿四氮杂大环配体的二价金属配合物的合成，结构表征和电位分析及其DNA裂解能力

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摘要

Four new metal complexes with an octadentate macrocyclic ligand [L = 1,4,7,10-tetrakis(2-carbamoylethyl)-1,4,7,10-tetraazacyclododecane] were synthesized and characterized by elemental analyses, IR and MS. These complexes have the general formula: M(L)(NO3)(2). nH(2)O [M = Co (1), Ni (2), n = 2; M = Cu (3), Zn (4), n = 1]. The structures of complexes 1, 2 and 3 have been determined by X-ray diffraction. [Co(L)(NO3)](NO3). 2H(2)O (1) crystallizes in the triclinic space group P (1) over bar. The refinement converges with R = 0.045 and R-w = 0.057 for 3233 reflections with (I > 2.5 sigma(I)). The Co has an octahedral geometry, and was coordinated with four amine nitrogen atoms of macrocyclic ligand and two or one acylate oxygen atoms derived from amide pendant groups. Two water molecules crystallize in the lattice cell and two kinds of hydrogen bonds exist between the coordinated acylate group and the water molecules: N(6)-H(27)... O(11) 2.158, N(8)-H(40)... O(12) 2.158 Angstrom or exist between the uncoordinated acylate group and the nitrate ion: N(5)-H(21)... O(8) 2.452, N(7)-H(33)... O(5) 2.256 Angstrom. [Ni(L)(NO3)](NO3). 2H(2)O (2) crystallizes in the monoclinic space group C2/c. The refinement converges with R = 0.044 and R-w = 0.059 for 2726 reflections with (I > 3 sigma(I)). The crystal of complex 2 has high symmetry with a C-2v symmetric operation. The central Ni atom is coordinated to four amine nitrogen atoms of macrocyclic skeleton and two acylate oxygen atoms of pendant amide groups. The polyhedron of the central atom can be described as a pseudo-octahedron. Two water molecules crystallized in the cell lattice. [Cu(L)](NO3)(2). H2O (3) crystallizes in the monoclinic space group P2(1). The refinement converges with R = 0.037 and R-w = 0.048 for 3174 reflections with (I > 2.5 sigma(I)). Complex 3 has a five-coordinated pyramid. The bond lengths of Co-O (av.) 2.088(3), Ni-O 2.089(2) Angstrom are almost equal, and are shorter than Cu-O 2.137(3) Angstrom. On the other hand, the bond lengths of Co-N (av.) and Ni-N (av.) are 2.194(3) and 2.153(2) Angstrom, respectively. Both of them are longer than Cu-N (av.) 2.0465(3) Angstrom. The potentiometric experiments in aqueous solution showed that the stability constants of three complexes were in the range of log K-ML = 17.11-15.00. The DNA cleavage results showed that the cobalt complex can effectively cleave supercoiled DNA to form nicked or linear DNA by performing single strand and double strand scissions under aerobic conditions in the presence of hydrogen peroxide as co-oxidant. Electron paramagnetic resonance results with the aid of DMPO as trapping agent demonstrated that the cleavage mechanism possibly occurred via hydroxy radical attacking. (C) 2000 Elsevier Science Ltd. All rights reserved. [References: 46]
机译：合成了四种具有八齿大环配体[L = 1,4,7,10-四（2-氨基甲酰基乙基）-1,4,7,10-四氮杂环十二烷]的金属配合物，并通过元素分析，IR和MS对其进行了表征。这些配合物的通式为：M（L）（NO3）（2）。 nH（2）O [M = Co（1），Ni（2），n = 2; M ＝ Cu（3），Zn（4），n ＝ 1]。配合物1、2和3的结构已经通过X射线衍射确定。 [Co（L）（NO3）]（NO3）。 2H（2）O（1）在棒上的三斜空间群P（1）中结晶。对于（I> 2.5 sigma（I））的3233次反射，细化收敛于R = 0.045和R-w = 0.057。 Co具有八面体的几何形状，并且与大环配体的四个胺氮原子和衍生自酰胺侧基的两个或一个酰化氧原子配位。两个水分子在晶格单元中结晶，配位的酰化物基团和水分子之间存在两种氢键：N（6）-H（27）... O（11）2.158，N（8）-H（ 40）... O（12）2.158埃或存在于未配位的酰化物基团和硝酸根离子之间：N（5）-H（21）... O（8）2.452，N（7）-H（33） ... O（5）2.256埃。 [Ni（L）（NO3）]（NO3）。 2H（2）O（2）在单斜空间群C2 / c中结晶。对于（I> 3 sigma（I））的2726次反射，精细度收敛于R = 0.044和R-w = 0.059。配合物2的晶体通过C-2v对称操作具有高对称性。中心的Ni原子与大环骨架的四个胺氮原子和酰胺侧基的两个酰化氧原子配位。中心原子的多面体可以描述为伪八面体。两个水分子在晶格中结晶。 [Cu（L）]（NO3）（2）。 H2O（3）在单斜空间群P2（1）/ n中结晶。对于（I> 2.5 sigma（I））的3174次反射，细化收敛于R = 0.037和R-w = 0.048。复杂物3具有五座金字塔。 Co-O（av。）2.088（3），Ni-O 2.089（2）埃的键长几乎相等，并且比Cu-O 2.137（3）埃短。另一方面，Co-N（av。）和Ni-N（av。）的键长分别为2.194（3）和2.153（2）埃。它们都比Cu-N（av。）2.0465（3）Ang长。在水溶液中的电位实验表明，三种配合物的稳定性常数在log K-ML = 17.11-15.00的范围内。 DNA切割结果表明，钴配合物可以通过在有氧条件下，在过氧化氢作为共氧化剂的条件下进行单链和双链切割，有效地切割超螺旋DNA，形成有切口的或线性的DNA。借助于DMPO作为捕集剂的电子顺磁共振结果表明，裂解机理可能是通过羟基自由基的攻击而发生的。 （C）2000 Elsevier ScienceLtd。保留所有权利。 [参考：46]

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