A series of five benzothiazolylhydrazone ligands 3a-3e and their seven novel Ru(II) polypyridine complexes 4a-4d, 5a, 5d, 5e of the type [Ru(N-N) 2 (L)]Cl 2 , where (N-N) 2 is 2,2 -bipyridine (bpy) 2 or 1,10-phenanthroline (phen) 2 and (L) is ligands 3a-3e, have been synthesized and characterized by elemental analysis, IR, 1 H NMR, electronic absorption, and emission spectral studies. The interpretation of the analytical data revealed that the ligands coordinate with the metal ion in a bidentate fashion through azomethine nitrogen and phenolic oxygen to form complexes. These ligands and complexes also exhibit absorption and luminescence properties.

Please cite this article as: S.K. Ahmed, S. Khaled, Syntheses, spectral characterization, thermal properties and DNA cleavage studies of a series of Co(II), Ni(II) and Cu(II) polypyridine complexes with some new imidazole derivatives of 1,10-phenanthroline, Arabian Journal of Chemistry (2015), doi: http://dx. AbstractIn the present study three new imidazole derivatives of phen, 2-(4-hydroxy-3,5-diiodophenyl) imidazo[4,5-f][1,10]phenathroline L 1 , 2-(2-hydroxy-3,5-diiodophenyl)imidazo[4,5-f][1,10]phenanthroline L 2 , 2-(4-hydroxy-5-iodo-3-methoxyphenyl)imidazo[4,5-f][1,10]phenanthroline L 3 and their nine new polypyridine complexes[M(N-N) 2 (L 1-3 )](OAc) 2 .(nH 2 O) where M is Ni(II), Co(II) and Cu(II) and where (N-N) 2 is 2,2'-bipyridine (bpy) 2 or 1,10-phenanthroline (phen) 2 have been synthesized from the reaction of the metal precursor complexes [M(phen) 2 (OAc) 2 ].(nH 2 O) and [M(bpy) 2 (OAc) 2 ].(nH 2 O) with the respective ligands in ethanol and water. The structures of the compounds were determined with the aid of elemental analysis and FT-IR, UV-Vis., 1 H NMR, ESR spectroscopic methods, magnetic measurements and conductance measurements, further analyzed by powder XRD and thermal studies. Elemental analysis data suggested that the complexes have a 1:2:1 molar ratio among the metal and phen or bpy and L 1 / L 2 or L 3 ligands. The spectral data show that all the complexes were six coordinated and possess octahedral geometry around the metal ions. The X-band ESR spectrum of the Cu(II) in DMSO solution at room temperature were recorded and observed anisotropic g values indicate the presence of metal ion in an octahedral environment. The powder XRD patterns of complexes recorded in the range (2θ = 0-80°) and average crystallite size (d XRD ) was calculated using Scherrer's formula. Thermal decomposition profiles of complexes show high decompound temperatures indicating a good thermal stability. Binding of the complexes with calf thymus DNA (CT DNA) has been investigated by gel electrophoresis. The experimental results indicate that the complexes bind to DNA by intercalation mode and found to promote cleavage of plasmid pBR 322 DNA from the supercoiled form I to the open circular form II upon irradiation.