Energy transfer from a rhodamine antenna to a ruthenium–bipyridine center

Abstract

The coordination of a modified rhodamine B (Rhod) to a bis-bipyridine ruthenium (II) (Ru–bpy) phototrigger complex enables a photodissociation reaction at longer wavelengths through enhanced absorption of green light (532 nm). The very high molar absorptivity of rhodamine (∼10⁵ M⁻¹ cm⁻¹) and the high quantum efficiency of Förster resonance energy transfer (FRET) from rhodamine to the Ru–bpy center (0.84) result in an unusually high photosensitivity and uncaging cross-section of the Ru–bpy–rhodamine complex at longer wavelengths.