DNA binding behaviors and cleavage properties of a Ru(II) polypyridyl complex

A novel complex, [Ru(phen)2pzip]2+ 1 (phen = 1,10-phenanthroline; pzip = 2-(pyrazine-2-yl)imidazo-[4,5-f][1,10]phenanthroline]), has been synthesized and characterized by elemental analysis, ES-MS, 1H NMR. The DNA-binding behaviors of this complex were studied by spectroscopic methods and viscosity measurements. The results indicate that the complex can bind to CT-DNA in an intercalative mode. When irradiated at 365 nm, complex 1 can promote the cleavage of plasmid pBR322DNA. Furthermore, Zn2+ can trigger the DNA cleavage of complex 1 without irradiation. The mechanism studies revealed that the DNA cleavage by complex 1 in the presence of Zn2+ is likely to proceed via a hydrolytic cleavage process.