Fluorescence and spectroscopic studies of the binding of cobalt imidazole phenantroline derivative to ct-dna: a thermodynamic approach

In this study, a cobalt (II) complex with 1,10-phenanthroline based ligand, [Co(FIP)2](OAC)2 with
FIP = 2-(Furan-2-yl)-1H-Imidazole[4,5-f] [1,10] phenanthroline as ligand, was synthesized and
characterized by spectroscopic methods and elemental analysis. The results show that the interaction
is endothermic and the driving force is entropy. In addition, the denaturation curves of ct-DNA
solution in the absence and presence of [Co(FIP)2](OAC)2 were studied between 24 - 86°C. The
results showed that increase of the [Co(FIP)2](OAC)2 concentration, ct-DNA will be more stable.
Finally, the [Co(FIP)2](OAC)2 complex bind to ct-DNA via hydrophobic mode as illustrated by
hyperchromism in the UV/Vis absorption band of [Co(FIP)2](OAC)2, and also the decreasing of
ethidium bromide (EtBr)-DNA solution fluorescence. Moreover, the competitive binding with a
standard intercalator like ethidium bromide (EB) indicate that the binding mode of [Co(FIP)2](OAC)2
with DNA is not a classical intercalation mode.