Synthesis of Diketo Copper(II) Complex and Its Binding toward Calf Thymus DNA (CTDNA)

ABSTRACT. A diketo-type ligand was synthesized by the Knoevenagel condensation reaction of thiophene-2-aldehyde with acetylacetone, subsequently its transition metal complexes with Cu(II), Ni(II), and Co(II) chlorides were also prepared. All the complexes were characterized by various physico-chemical methods. The molar conductivity data reveals ionic nature for the complexes. The electronic spectrum and the EPR values suggest square planar geometry for the Cu(II) ion. Interaction of the Cu(II) complex with CTDNA (calf thymus DNA) was studied by absorption spectral method and cyclic voltammetry. The kobs values versus [DNA] gave a linear plot suggesting psuedo-first order reaction kinetics. The cyclic voltammogram of the Cu(II) complex reveals a quasi-reversible wave attributed to Cu(II)/Cu(I) redox couple for one electron transfer with E1/2 values-0.240 V and-0.194 V. respectively. On addition of CTDNA, there is a shift in the E1/2 values 168 mV and 18 mV respec-tively and decrease in Ep values. The shift in E1/2 values in the presence of CTDNA suggests strong binding of Cu(II) comple