Interaction of Ruthenium(II)‐dipyridophenazine Complexes with CT‐DNA: Effects of the Polythioether Ancillary Ligands

Abstract

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.

Structural studies on supramolecular adducts of cyclodextrins with the complex [Ru([9]aneS3)(bpy)Cl]Cl

“…The crystal structures of these compounds were found to be largely stabilised by hydrogen bonding interactions and the coordinated planar aromatic amines exhibit p-stacking arrangements which mimic the structure of polypyridyl complexes intercalated with DNA. The intercalative properties of some of these compounds have also been demonstrated by UV-Vis titration studies, in particular for [Ru( [9] aneS 3 )dppzCl]Cl (dppz = dipyrido [3,2a:2 0 ,3 0 c] phenazine) [18]. Following the strategy of molecular encapsulation that allowed us to improve the cytotoxic properties of molybdenocene dichloride [4b], here we wish to report the first supramolecular adducts of the trithyacyclononane-Ru(II) guest [Ru( [9]aneS 3 )(bpy)Cl]Cl (bpy = 2,2 0 -bipyridine) with the cyclodextrin hosts b-CD and 2,3,6-tri-O-methyl-b-CD (TRIMEB).…”

Cyclodextrins improve the antimicrobial activity of the chloride salt of Ruthenium(II) chloro-phenanthroline-trithiacyclononane

“…(L = ethylenediamine or polycyclic arenes) (Yan et al 2005; Ronconi and Sadler 2007;Habtemariam et al 2006), (iii) arene-free analogues bearing the face capping ligand trithiacyclononane- [9]aneS 3 (Serli et al 2005) and DNA-intercalating planar polypyridylic ligands (Madureira et al 2000;Goodfellow et al 1997;Santos et al 2001). …”

Isolation, crystal structure, and cytotoxicity on osteosarcoma of a ruthenium(III) complex with coordinated acetonitrile

“…The solid compound unexpectedly comprises an Ru(III) specimen, [Ru( [9]aneS 3 )(NCMe) 2 Cl]Cl 2 (2). Although uncommon, oxidation of Ru(II) to Ru(III) in nitrile complexes is not unprecedented, being well-described in the complex cation [Ru(NH 3 ) 5 (NCMe)] 2þ [24] and in [Ru(NH 3 ) 5 (NCR)] 2þ (where NCR ¼ isonicotinonitrile) [25].…”

“…Single-crystals of [Ru(III)( [9]aneS 3 )(NCMe) 2 Cl]Cl 2 Á 2H 2 O (2) directly harvested from the crystallization vials were immediately immersed in highly viscous FOMBLIN Y perfluoropolyether vacuum oil (LVAC 140/13, Sigma-Aldrich) to avoid degradation caused by evaporation of the solvent. Crystals were mounted on a Hampton Research CryoLoop with the help of a Stemi 2000 stereomicroscope equipped with Carl Zeiss lenses [15].…”