title: Interaction of Ruthenium(II)-dipyridophenazine Complexes with CT-DNA: Effects of the Polythioether Ancillary Ligands.
abstract: The complexes [Ru([9]aneS(3))(dppz)Cl]Cl 1 and [Ru([12]aneS(4))(dppz)]Cl(2)2 ([9]aneS(3) = 1,4,7- trithiaciclononane and [12]aneS(4) = 1,4,7,10-tetrathiaciclododecane) were synthesised and fully characterised. These complexes belong to a small family of dipyridophenazine complexes with non-polypyridyl ancillary ligands . Interaction studies of these complexes with CT-DNA (UV/Vis titrations, steady-state emission and thermal denaturation) revealed their high affinity for DNA . Intercalation constants determined by UV/Vis titrations are of the same order of magnitude (10(6)) as other dppz metallointercalators, namely [Ru(II)(bpy)(2)dppz]S(2+). Differences between l and2 were identified by steady-state emission and thermal denaturation studies . Emission results are in accordance with structural data, which indicate how geometric distortions and different donor and/or acceptor ligand abilities affect luminescence. The possibility of noncovalent interactions between ancillary ligands and nucleobases by van der Waals contacts and H-bridges is discussed . Furthermore, complex l undergoes aquation under intra-cellular conditions and an equilibrium with the aquated form l' is attained . This behaviour may increase the diversity of available interaction modes.
authors.affiliation: Department of Chemistry University of Aveiro Campus Universitário de Santiago Aveiro 3810-193 Portugal.
authors.forename: T M
authors.initials: TM
authors.lastname: Santos
authors.forename: J
authors.initials: J
authors.lastname: Madureira
authors.forename: B J
authors.initials: BJ
authors.lastname: Goodfellow
authors.forename: M G
authors.initials: MG
authors.lastname: Drew
authors.forename: J P
authors.initials: JP
authors.lastname: de Jesus
authors.forename: V
authors.initials: V
authors.lastname: Félix