The interaction of native calf thymus DNA with Zn(II)-N,N'-bis(5,5'-triethylammoniomethyl-salicylidene)phenylendiimine

The interaction between native calf thymus deoxyribonucleic acid (DNA) and Fe-III-N,N'-ethylene-bis (salicylideneiminato)chloride, Fe(Salen)Cl, was investigated in aqueous solutions by UV-visible (UV-vis) absorption, circular clichroisin (CD), thermal denaturation and viscosity measurements. The results obtained from CD, UV-vis and viscosity measurements exclude DNA intercalation and can be interpreted in terms of an electrostatic binding between the Fe(Salen)(+) cation and the phosphate groups of DNA. The trend of the UV-vis absorption band of the Fe(Salen)Cl complex at different ratios [DNA(phosphate)]/[Fe(Salen)Cl] and the large increase of the melting temperature of DNA in the presence …