DNA interactions of new mixed-ligand complexes of cobalt(III) and nickel(II) that incorporate modified phenanthroline ligands

Sastri, C. V. ; Eswaramoorthy, D. ; Giribabu, L. ; Maiya, Bhaskar G. (2003) DNA interactions of new mixed-ligand complexes of cobalt(III) and nickel(II) that incorporate modified phenanthroline ligands Journal of Inorganic Biochemistry, 94 (1-2). pp. 138-145. ISSN 0162-0134

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Official URL: http://linkinghub.elsevier.com/retrieve/pii/S01620...

Related URL: http://dx.doi.org/10.1016/S0162-0134(02)00622-0

Abstract

Four new mixed-ligand complexes, namely [Co(phen)2(qdppz)]3+, [Ni(phen)2(qdppz)]2+, [Co(phen)2(dicnq)]3+ and [Ni(phen)2(dicnq)]2+ (phen=1,10-phenanthroline, qdppz=naptho[2,3-a]dipyrido[3,2-h:2',3'-f]phenazine-5,18-dione and dicnq=dicyanodipyrido quinoxaline), were synthesized and characterized by FAB-MS, UV/Vis, IR, 1H NMR, cyclic voltammetry and magnetic susceptibility methods. Absorption and viscometric titration as well as thermal denaturation studies revealed that each of these octahedral complexes is an avid binder of calf-thymus DNA. The apparent binding constants for the dicnq- and qdppz-bearing complexes are in the order of 104 and >106 M-1, respectively. Based on the data obtained, an intercalative mode of DNA binding is suggested for these complexes. While both the investigated cobalt(III) complexes and also [Ni(phen)2(qdppz)]2+ affected the photocleavage of DNA (supercoiled pBR 322) upon irradiation by 360 nm light, the corresponding dicnq complex of nickel(II) was found to be ineffective under a similar set of experimental conditions. The physico-chemical properties as well as salient features involved in the DNA interactions of the cobalt(III) and nickel(II) complexes investigated here were compared with each other and also with the corresponding properties of the previously reported ruthenium(II) analogues.

Item Type:Article
Source:Copyright of this article belongs to Elsevier Science.
Keywords:Cobalt(III) and Nickel(II) Complexes; Modified Phenanthroline Ligands; Synthesis and Spectroscopy; DNA Binding and Photocleavage
ID Code:31949
Deposited On:31 Mar 2011 10:34
Last Modified:09 Jun 2011 09:43

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