The complexes [Ru([9]aneS3)(dppz)Cl]Cl 1 and [Ru([12]aneS4)(dppz)]Cl2,2 ([9]aneS3 = 1,4,7-
trithiaciclononane and [12]aneS4 = 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 (106) as other dppz metallointercalators, namely
[Ru(II)(bpy)2dppz]S2+. 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.
