Distant ultrafast energy transfer in a trimetallic {Ru-Ru-Cr} complex facilitated by hole delocalization.

Multi-metallic complexes based on {Ru-Cr}, {Ru-Ru} and {Ru-Ru-Cr} fragments are investigated for their light-harvesting and long-range energy transfer properties. We report the synthesis and characterization of [Ru(tpy)(bpy)(μ-CN)Ru(py)Cl] and [Ru(tpy)(bpy)(μ-CN)Ru(py)(μ-NC)Cr(CN)]. The intercalation of {Ru(py)} linked by cyanide bridges between {Ru(tpy)(bpy)} and {Cr(CN)} results in efficient, distant energy transfer followed by emission from the Cr moiety.