DNA Minor Groove Binding with Bisbenzamidine-Ru(II) Complexes

We report the first Ru(II) coordination compounds that interact with DNA through a canonical minor groove insertion mode and with selectivity for A/T rich sites. This was made possible by integrating a bis‑benzamidine minor groove DNA-binding agent with a ruthenium(II) complex. Importantly, one of the enantiomers (Δ‑[Ru(bpy)₂b4bpy]²⁺, Δ‑4Ru) shows a considerably higher DNA affinity than the parent organic ligand and than the other enantiomer, particularly for the AATT sequence, while the other enantiomer preferentially targets long AAATTT sites with overall lower affinity. Finally, we demonstrate that the photophysical properties of these new binders can be exploited for DNA cleavage using visible light.