DNA-Targeting RuII -Polypyridyl Complex with a Long-Lived Intraligand Excited State as a Potential Photodynamic Therapy Agent

Abstract

Subtle ligand modifications on Ru^II -polypyridyl complexes may result in different excited-state characteristics, which provides the opportunity to tune their photo-physicochemical properties and subsequently change their biological functions. Here, a DNA-targeting Ru^II -polypyridyl complex (named Ru1) with highly photosensitizing ³ IL (intraligand) excited state was designed based on a classical DNA-intercalator [Ru(bpy)₂ (dppz)]⋅2 PF₆ by incorporation of the dppz (dipyrido[3,2-a:2',3'-c]phenazine) ligand tethered with a pyrenyl group, which has four orders of magnitude higher potency than the model complex [Ru(bpy)₂ (dppz)]⋅2 PF₆ upon light irradiation. This study provides a facile strategy for the design of organelle-targeting Ru^II -polypyridyl complexes with dramatically improved photobiological activity.

Keywords: DNA; Ru polypyridyl complexes; photodynamics; reactive oxygen species (ROS).