Directing Protons to the Dioxygen Ligand of a Ruthenium(II) Complex with Pendent Amines in the Second Coordination Sphere

Directing Protons to the Dioxygen Ligand of a Ruthenium(II) Complex with Pendent Amines in the Second Coordination Sphere:

Proton relay: A side-on Ru–O₂ complex with pendent amines in the ligand backbone has been synthesized to model proton delivery in O₂ reduction (see scheme and structure; red O, purple Ru, blue N, yellow P). Protonation occurs at the amine near the O₂ ligand, forming a hydrogen bond between the ammonium ion and the O₂ ligand, leading to small increase in OO bond length.

Ruthenium arene complex of DuBois' PNP ligand