Ligand-Triplet-Fueled Long-Lived Charge Separation in Ruthenium(II) Complexes with Bithienyl-Functionalized Ligands

Ruthenium(II) polypyridyl complexes with pendant bithienyl ligands exhibiting unusually long-lived (τ ∼ 3–7 μs) charge-separated excited states and a large amount of stored energy (Δ<i>G</i>° ∼ 2.0 eV) are reported. A long-lived ligand-localized triplet acts as an energy reservoir to fuel population of an interligand charge-transfer state via an intermediate metal-to-ligand charge-transfer state in these complexes.