Synthesis, structure, DNA-binding properties and antioxidant activity of silver(i) complexes containing V-shaped bis-benzimidazole ligands
作者:Huilu Wu、Jingkun Yuan、Ying Bai、Guolong Pan、Hua Wang、Jin Kong、Xuyang Fan、Hongmei Liu
DOI:10.1039/c2dt30512g
日期:——
A V-shaped ligand bis(2-benzimidazol-2-ylmethyl)benzylamine L1 with its two derivatives bis(N-methylbenzimidazol-2-ylmethyl)benzylamine L2 and bis(N-benzylbenzimidazol-2-ylmethyl)benzylamine L3 have been prepared. Reaction of these shape-specific designed ligands with Ag(pic) (pic = picrate) afforded three novel complexes, namely, [Ag2L12](pic)21, [Ag2L22](pic)2·2DMF 2 and [AgL3(pic)] 3. The ligands and complexes were characterized on the basis of elemental analysis, UV-Vis, IR, NMR spectroscopy and X-ray crystallography. Complex 1 is a dinuclear metallacycle with a 2-fold rotational symmetry in which two syn-conformational L1 ligands are connected by two linearly coordinated Ag(I) atoms. Due to the strong interaction between two adjacent Ag(I) atoms, the coordination mode of the central Ag(I) atom can be described as T-shaped. Complex 2 consists of a centrosymmetric dinuclear pore canal structure assembled from two nearly linearly coordinated Ag(I) atoms and two L2 ligands. The structure of complex 3 adopts a four-coordinate environment for AgN2O2, with the counterion participating in an eight-shaped geometry. In order to explore the relationship between the structure and biological properties, the DNA-binding properties have been investigated by viscosity measurements, electronic absorption, and fluorescence. The results suggest that the ligands and complexes bind to DNA in an intercalation mode, and their binding affinities for DNA are also different. Moreover, the three Ag(I) complexes also exhibited potential antioxidant properties in vitro studies.
制备了一种V形配体双(2-苯并咪唑-2-基甲基)苄胺L1及其两种衍生物双(N-甲基苯并咪唑-2-基甲基)苄胺L2和双(N-苄基苯并咪唑-2-基甲基)苄胺L3。这些特定形状设计的配体与Ag(苦味酸根离子)(pic=苦味酸根离子)反应,得到了三种新型配合物,即[Ag2L12](pic)21、[Ag2L22](pic)2·2DMF 2和[AgL3(pic)] 3。根据元素分析、紫外-可见光谱、红外光谱、核磁共振波谱和X射线晶体学对配体和配合物进行了表征。配合物1是一种具有2重旋转变换对称性的双核金属环,其中两个顺式构象的L1配体通过两个线性配位的Ag(I)原子连接。由于两个相邻的Ag(I)原子之间存在较强的相互作用,中心Ag(I)原子的配位模式可以描述为T形。配合物2由两个近似线性配位的Ag(I)原子和两个L2配体组装成了一个中心对称的双核孔道结构。配合物3采用了AgN2O2的四配位环境,并且反离子参与了8字形几何构型。为了探究结构和生物活性之间的关系,通过粘度测定、电子吸收和荧光光谱法研究了其与DNA的结合特性。结果表明,配体和配合物均以插入方式结合DNA,并且它们对DNA的结合亲和力也不同。此外,三种Ag(I)配合物在体外研究中还表现出潜在的抗氧化性质。