[Ru(bpy)3−n(dpb)n]2+: Unusual Photophysical Property and Efficient DNA Photocleavage Activity

The sequential replacement of a bpy ligand (bpy = 2,2′-bipyridine) by a dpb ligand (dpb = 2,3-bis(2-pyridyl) benzoquinoxaline) in the series [Ru(bpy)3−n(dpb)n]2+ (n = 1−3) leads to a remarkable increase of the excited state lifetime, the 1O2 quantum yield, and the binding affinity toward dsDNA, rendering both [Ru(bpy)(dpb)2]2+ and [Ru(dpb)3]2+ efficient DNA photocleavage activities upon red light irradiation (≥600 nm).