Hexakis(1H-imidazole-κN 3)cobalt(III) tris­(hexa­fluoridophosphate) hexa­hydrate

In the crystal structure of the title compound, [Co(C3H4N2)6](PF6)3·6H2O, the CoIII atom lies on a special position with site-symmetry and the P atom is located on a special position with site symmetry . The CoIII atom has an almost ideal octa­hedral coordination formed by the N atoms of six imidazole ligands. The water mol­ecules form hydrogen-bonded helical chains propagating in [001] by O—H⋯O inter­actions with a distance of 2.913 (2) Å. They simultaneously inter­act as hydrogen-bond acceptors and donors with the cations and anions, respectively, resulting in the formation of a three-dimensional assembly. Weak C—H⋯F inter­actions further stabilize the crystal structure

Binding studies of metal–salphen and metal–bipyridine complexes towards G‐Quadruplex DNA

The proposed in vivo formation of G-quadruplex DNA (G4 DNA) in promoter regions of oncogenes and in telomeres has prompted the development of small molecules with high affinity and selectivity for these structures. Herein we report the synthesis of a new di-substituted bipyridine ligand and the corresponding complexes with Ni2+ and VO2+. Both these new complexes have been characterized spectroscopically and by X-ray crystallography. Detailed DNA binding studies of these two complexes, together with three previously reported metal salphen complexes, are presented. Using FRET melting assays, the binding affinity and selectivity of the five metal complexes against six different G4 DNA structures as well as a duplex DNA have been determined. In addition, we present detailed ITC and UV/Vis studies to characterize the interaction of the complexes with human telomeric G4 DNA. Finally, we show via a polymerase stop assay that these complexes are able to stabilize a G4 DNA structure (from the c-Myc oncogene promoter) and halt the activity of Taq polymerase.UK’s Engineering and Physical Sciences Research Council (EPSRC) (grant number: EP/H005285/1