Communication: Water activation and splitting by single metal-atom anions

We report experimental and computational results pertaining to the activation and splitting of single water molecules by single atomic platinum anions. The anion photoelectron spectra of [Pt(H₂O)]^-, formed under different conditions, exhibit spectral features that are due to the anion-molecule complex, Pt^-(H₂O), and to the reaction intermediates, HPtOH^- and H₂PtO^-, in which one and two O-H bonds have been broken, respectively. Additionally, the observations of PtO^- and H₂ ⁺ in mass spectra strongly imply that water splitting via the reaction Pt^- + H₂O → PtO^- + H₂ has occurred. Extending these studies to nickel and palladium shows that they too are able to activate single water molecules, as evidenced by the formation of the reaction intermediates, HNiOH^- and HPdOH^-. Computations at the coupled cluster singles and doubles with perturbatively connected triples level of theory provide structures and vertical detachment energies (VDEs) for both HMOH^- and H₂MO^- intermediates. The calculated and measured VDE values are in good agreement and thus support their identification.