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

Abstract

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.

Electron transfer reaction of Tris(1,10-phenanthroline) cobalt(III) complex [Co(phen)3]3+ and thiosulphate ion (S2O32−) in an aqueous acidic medium

“…Kinetic studies have been previously carried out on several chemical and biological compounds but there has been growing interest towards transition metal complexes, this is because of the wide range of applications of metal complexes resulting from the peculiarity in the physical and chemical properties of transition metals that form such complexes. The metal complexes of diimine ligands such as 1,10-phenanthroline and 2,2'-bipyridine have received much research interest because of their versatile roles as building blocks in synthesis as well as their bioinorganic and biomedicinal applications (Wang et al 2014, Ahmed & Khaled 2015, Gopinathan & Arumugham 2015, Molphy et al 2015. Based still on the peculiarity of transition metal properties, metal complexes can either function as a reductant or an oxidant in an electron transfer reaction with other metal complexes or with other compounds, thus have attracted a lot of kinetic studies on them.…”

“…The concentration of the complex assuming a zero order with respect to the reaction, S2O3 2assuming a second order and the [H + ] taking up a first order was as a result of the equilibrium association of these species. Subsequent reactions that occurred including the backward reaction in equation(5) took place in a series of fast steps as shown below in the reaction mechanism. result of acid dependence on rate is in agreement with equation(6) − ⁄ [{Co(phen) 3} 3+ ] = a [H + ] [S2O3 2− ] 2…”

Formation and Structural Characterization of Metal Complexes derived from Thiosalicylic Acid

“…The presence of intense peak in the region of 714-717 cm -1 was due to C-S bond. The presence of bands in the region 500-650 cm -1 corresponded to Zn-O (557), [27] Zn-N (642), Ni-N (653), Ni-O (550), Co-N (608), [28] and Co-O (518 cm -1 ). When CuCl 2 was reacted with TSA in the presence of bipy, a green powder [Cu(bipy)Cl 2 ] and dark blue crystals of the dimeric complex [Cu 2 (tdb) 2 (bipy) 2 ] (5) (tdb = thiodibenzoic acid) were isolated.…”