title: Synthesis, characterization, and DNA-binding and -cleavage properties of dinuclear Cu(II) --salophen/salen complexes.
abstract: Dinuclear Cu(II) complexes, [Cu(2) (salophen)(2) ] (1) and [Cu(2) (salen)(2) ] (2), with Schiff bases derived from salicylaldehyde and o-phenylenediamine (ophen) or ethylenediamine (en) were synthesized and characterized. They exhibit square-planar geometry with CuN(2) O(2) coordination, where the dianionic Schiff base acts as a tetradentate N(2) O(2) donor ligand. Calf thymus (CT)-DNA Binding studies revealed that the complexes possess good binding propensities (K(b) =3.13×10(5) for 1 and K(b) =2.99×10(5)  M(-1) for 2). They show good DNA-cleavage abilities under oxidative and hydrolytic conditions. Complex 1 binds and cleaves DNA more efficiently as compared to 2 due to the presence of an extended aromatic phenyl ring which might be involved in an additional stacking interaction with DNA bases. From the kinetic experiments, hydrolytic DNA-cleavage rate constants were determined as 1.54 for 1 and 0.72 h(-1) for 2. The nuclease activities of 1 and 2 are significant, giving rise to (2.03-2.88)×10(7) -fold rate enhancement compared to non-catalyzed DNA cleavage.
authors.affiliation: Department of Chemistry, Osmania University, Hyderabad-500 007, India. rabi_pr@rediffmail.com
authors.forename: Pulimamidi
authors.initials: P
authors.lastname: Rabindra Reddy
authors.forename: Addla
authors.initials: A
authors.lastname: Shilpa
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology; D001665:Binding Sites; D002417:Cattle; D003300:Copper / Q000737:chemistry* / Q000494:pharmacology; D004247:DNA / Q000378:metabolism*; D053837:DNA Cleavage / Q000187:drug effects*; D005029:Ethylenediamines / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology; D008958:Models, Molecular; D009369:Neoplasms / Q000188:drug therapy; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D012459:Salicylates / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology; D012545:Schiff Bases / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology
chemical_list: D000970:Antineoplastic Agents; D005029:Ethylenediamines; D009942:Organometallic Compounds; D012459:Salicylates; D012545:Schiff Bases; C090416:salophen; D003300:Copper; D004247:DNA; C427203:calf thymus DNA; C011452:disalicylaldehyde ethylenediamine