Merging of a Perylene Moiety Enables a Ru^II Photosensitizer with Long‐Lived Excited States and the Efficient Production of Singlet Oxygen

Abstract

Abstract Multichromophoric systems based on a Ru II polypyridine moiety containing an additional organic chromophore are of increasing interest with respect to different light‐driven applications. Here, we present the synthesis and detailed characterization of a novel Ru II photosensitizer, namely [(tbbpy) 2 Ru((2‐(perylen‐3‐yl)‐1 H ‐imidazo[4,5‐ f ][1,10]‐phenanthrolline))](PF 6 ) 2 RuipPer , that includes a merged perylene dye in the back of the ip ligand. This complex features two emissive excited states as well as a long‐lived (8 μs) dark state in acetonitrile solution. Compared to prototype [(bpy) 3 Ru] 2+ ‐like complexes, a strongly altered absorption ( ϵ =50.3×10 3 M −1 cm −1 at 467 nm) and emission behavior caused by the introduction of the perylene unit is found. A combination of spectro‐electrochemistry and time‐resolved spectroscopy was used to elucidate the nature of the excited states. Finally, this photosensitizer was successfully used for the efficient formation of reactive singlet oxygen.