Spectroscopic and DNA interaction studies on mixed ligand copper(II) complexes of dicyanamide with ethylenediamine or 1,3-diaminopropane

Mixed ligand copper(II) complexes of dicyanamide with different polyamines, viz. ethylenediamine (1) and 1,3-diaminopropane (2), have been synthesized and characterized. The crystal structure of complex 1 contains a five-coordinated copper in a distorted square-pyramidal environment and forms 1D zig-zag polymeric chain via the bridging ligand dicyanamide. Hydrogen bonding contributes supramolecular architecture in the crystal. Electronic spectral studies suggest the distorted square-pyramidal structure of the complexes. The interaction of the copper(II) complexes with calf-thymus DNA reveals nonintercalative binding mode. The two complexes have antimicrobial activity against the bacteria (viz. Salmonella paratyphi), which is responsible for paratyphoid fever.

本研究合成并表征了二氰胺根（dicyanamide）与不同多胺构成的混合配体铜(II)配合物，所用多胺分别为乙二胺（ethylenediamine，记为1）和1,3-丙二胺（1,3-diaminopropane，记为2）。配合物1的晶体结构显示，其中心铜离子为五配位，处于畸变四方锥配位环境中，并通过桥联配体二氰胺根形成一维锯齿状聚合物链。晶体中的氢键作用构筑了超分子架构。电子光谱研究证实了该类配合物的畸变四方锥结构。该系列铜(II)配合物与小牛胸腺DNA的相互作用研究表明，二者以非插入结合模式结合。两种配合物均对副伤寒沙门氏菌（Salmonella paratyphi）具有抗菌活性，该菌正是引发副伤寒（paratyphoid fever）的病原菌。