Nature of Anti‐Dissipative High‐Energy Excited States in Quaterpyridine‐Bridged Ruthenium Complexes

Abstract High‐energy excited states with slow rates for internal conversion to the lowest‐energy excited state are prone to be intercepted before they dissipate energy to the medium. In a previous report, oligomeric Ru(II) photosensitizers bearing a bridging 2,2′:5′,3″:6″,2 ‴ –quaterpyridine scaffold showed promising anti‐dissipative behavior in photoinduced electron transfer reactivity. In here, a range of electron accepting and electron donating substituents were incorporated on the ancillary 2,2′‐bipyridine ligands to modulate the excited‐state dynamics. This allowed to unambiguously identify the nature of high‐energy excited states and derive design guidelines for the achievement of anti‐dissipative behavior in oligomeric Ru(II) polypyridines relevant for solar fuels production and photoredox catalysis.