Ru(II) Dyads Derived from 2-(1-Pyrenyl)-1H-imidazo[4,5- f ][1,10]phenanthroline: Versatile Photosensitizers for Photodynamic Applications

Combining the best attributes of organic photosensitizers with those of coordination complexes is an elegant way to achieve prolonged excited state lifetimes in Ru(II) dyads. Not only do their reduced radiative and nonradiative rates provide ample time for photosensitization of reactive oxygen species at low oxygen tension, but they also harness the unique properties of 3IL states that can act as discrete units or in concert with 3MLCT states. The imidazo(4,5-f )(1,10)phenanthroline framework provides a convenient tether for linking p-expansive ligands such as pyrene to a Ru(II) scaffold, and the stabilizing coligands can fine-tune the chemical properties of these bichromophoric systems. The resulting dyads in this study demonstrate the versatility of these highly potent photosensitizers in destroying both cancer and bacterial cells, and expand the scope of compounds that utilize low-lying 3IL states for photobiological applications.