Abstract
New metal-based chemotherapeutic drug candidate [Co(L)(2)center dot(H2O)(4)] (1) was synthesized from ligand 4(pyridin-4-ylmethoxy)-benzoic acid (HL) and thoroughly characterized by spectroscopic, analytical and single crystal X-ray diffraction techniques. The crystal structure analysis reveal that the asymmetric unit of the complex consists of one Co(II) ion, one L- ligand and two coordinated aqua molecules. The Co(m) ion is coordinated to four oxygen atoms from four aqua molecules. Hence, the geometry around the Co(II) ion can be described as a MN2O4 octahedral geometry. In vitro DNA binding studies of complex 1 with CT DNA were carried out by employing various biophysical techniques viz, electronic absorption, fluorescence and circular dichroism techniques to examine the binding propensity of 1 towards CT DNA. The experimental results revealed that complex 1 avidly binds to CT DNA via an electrostatic mode and the intrinsic binding constant Kb value was found to be 4.25 x 10(4) M-1. Complex 1 shows significant DNA photo cleavage activity through the formation of hydroxyl radicals via a photo-redox pathway. Futhermore, interaction studies of complex 1 with human serum albumin (HSA) revealed the quenching of intrinsic fluorescence of the HSA Trp 214 residue through a static quenching mechanism.