MIXED LIGAND COMPLEXES OF CU(II),/NI(II)/ ZN(II) IONS CONTAINING 1,2-DI(2-THIENYL)-1,2-ETHANEDIONE, HYDRAZINE HYDRATE AND METHYL SALICYLALDEHYDE: SYNTHESIS, CHARACTERIZATION AND DNA BINDING ACTIVITY

Three new metal complexes derived from the reaction of Cu(II), Ni(II) and Zn(II) acetates with the Schiff-base ligand (HL) resulted from the condensation of the 1,2-Di(2-thienyl)-1,2-ethanedione (Thenil), hydrazine hydrate and 2-Hydroxy-5-methylbenzaldehyde have been synthesized. The structure of the synthesized ligand and complexes was characterized by, elemental analyses, Mass, IR, UV–Vis., measurements. The binding properties of these complexes towards DNA have been investigated using electronic absorption, competitive fluorescence titration, viscosity measurements and circular dichroic analyses. The results obtained indicated that the complexes get bonded with DNA via an intercalation binding mode with an intrinsic binding constant, Kb 5.01 x 104 M-1 , 4.68 x 104 M-1 and 4.21 x 104 M-1 and Kapp of 5.82 x 105 M-1 , 4.97 x 105 M-1 and 4.29 x 105 M-1 . Keywords: Thenil, DNA binding, methyl salicylaldehyde, Intercalation, hydrazine hydrate.