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

In the present study three new imidazole derivatives of phen, 2-(4-hydroxy-3, 5-diiodophenyl) imidazo[4,5- f][1,10]phenanthroline 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)(L1-3)](OAc)(2)center dot(nH(2)O) where M is Ni(II), Co(II) and Cu(II) and where (N-N)(2) is 2,20-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)]AE(nH2O) and [M(bpy)(2)(OAc)(2)]AE(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, H-1 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 was 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 (2h= 0-80 degrees) and average crystallite size (dXRD) was calculated using Scherrer's formula. Thermal decomposition profiles