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


  • This work is supported as part of the Center for Molecular Electrocatalysis, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under FWP 56073. We thank Dr. Rajan Paranji for NMR assistance and Dr. Jenny Yang for 15N-labeled P2N2 ligand. M.R.D. and T.L. were supported by the Division of Chemical Sciences, Biosciences and Geosciences, Office of Basic Energy Sciences, Office of Science of the U.S. Department of Energy. Pacific Northwest National Lab is operated by Battelle for the U.S. Department of Energy.


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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 a small increase in O[BOND]O bond length.