Oxidative DNA cleavage mediated by a new copper (II) terpyridine complex: Crystal structure and DNA binding studies

The copper (II) complex [Cu(Itpy)2](ClO4)2 (1), (Itpy = imidazole terpyridine) has been synthesized and structurally characterized. Crystal structure of the complex shows the complex to be a monomeric copper (II) species with two Itpy ligands coordinated to the metal ion to give a six coordinate complex. The complex has a distorted octahedral geometry with axial elongation. Variable temperature crystal structure data shows dynamic nature of the Jahn-Teller distortion. The complex is an avid DNA binder with a binding constant of 4.26 ± 0.20 × 103 M−1. Observed changes in the viscosity and circular dichroic spectrum of calf thymus DNA solution in the presence of complex 1 suggests intercalative binding of complex 1 to DNA. The complex cleaves supercoiled pBR322 DNA oxidatively in the presence of hydrogen peroxide.