title: Electrochemical and Resonance Raman Spectroscopic Studies of Water-Oxidizing Ruthenium Terpyridyl-Bipyridyl Complexes.
abstract: The irreversible conversion of single-site water-oxidation catalysts (WOC) into more rugged catalysts structurally related to [(trpy)(5,5'-X2-bpy)RuIV(μ-O)RuIV(trpy)(O)(H2O)]4+(X=H, 1-dn4+; X=F, 2-dn4+; bpy=2,2'-bipyridine; trpy=2,2':6',2"-terpyridine) represents a critical issue in the development of active and durable WOCs. In this work, the electrochemical and acid-base properties of 1-dn4+and 2-dn4+were evaluated. In situ resonance Raman spectroscopy was employed to characterize the species formed upon the stoichiometric oxidation of the single-site catalysts and demonstrated the formation of high-oxidation-state mononuclear Ru=O and RuO-O complexes. Under turnover conditions, the dinuclear intermediates, 1-dn4+and 2-dn4+as well as the previously proposed [RuVI(trpy)(O)2(H2O)]2+complex (32+) are formed. Complex 32+is a pivotal intermediate that provides access to the formation of dinuclear species. Single-crystal X-ray diffraction analysis of the isolated complex [RuIV(O)(trpy)(5,5'-F2-bpy)]2+reveals a clear elongation of the Ru-N bond trans to the oxido ligand that documents the weakness of this bond, which promotes the release of the bpy ligand and the subsequent formation of 32+.
authors.affiliation: Institut für Chemie, Technische Universität Berlin, Sekr. PC14, Straße des 17. Juni 135, 10623, Berlin, Germany.
authors.forename: Anke
authors.initials: A
authors.lastname: Keidel
authors.affiliation: Institute of Chemical Research of Catalonia (ICIQ), Barcelona Institute of Science and Technology (BIST), Av. Països Catalans, 16, 43007, Tarragona, Spain.
authors.forename: Isidoro
authors.initials: I
authors.lastname: López
authors.affiliation: Institut für Chemie, Technische Universität Berlin, Sekr. PC14, Straße des 17. Juni 135, 10623, Berlin, Germany.
authors.forename: Jana
authors.initials: J
authors.lastname: Staffa
authors.affiliation: Institut für Chemie, Technische Universität Berlin, Sekr. PC14, Straße des 17. Juni 135, 10623, Berlin, Germany.
authors.forename: Uwe
authors.initials: U
authors.lastname: Kuhlmann
authors.affiliation: Institute of Chemical Research of Catalonia (ICIQ), Barcelona Institute of Science and Technology (BIST), Av. Països Catalans, 16, 43007, Tarragona, Spain.
authors.forename: Fernando
authors.initials: F
authors.lastname: Bozoglian
authors.affiliation: Institute of Chemical Research of Catalonia (ICIQ), Barcelona Institute of Science and Technology (BIST), Av. Països Catalans, 16, 43007, Tarragona, Spain.
authors.forename: Carolina
authors.initials: C
authors.lastname: Gimbert-Suriñach
authors.affiliation: Institute of Chemical Research of Catalonia (ICIQ), Barcelona Institute of Science and Technology (BIST), Av. Països Catalans, 16, 43007, Tarragona, Spain.
authors.forename: Jordi
authors.initials: J
authors.lastname: Benet-Buchholz
authors.affiliation: Institut für Chemie, Technische Universität Berlin, Sekr. PC14, Straße des 17. Juni 135, 10623, Berlin, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Hildebrandt
authors.affiliation: Institute of Chemical Research of Catalonia (ICIQ), Barcelona Institute of Science and Technology (BIST), Av. Països Catalans, 16, 43007, Tarragona, Spain.|Departament de Química, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, 08193, Barcelona, Spain.
authors.forename: Antoni
authors.identifier: 0000-0002-6176-5272
authors.initials: A
authors.lastname: Llobet
mesh_terms: D015082:2,2'-Dipyridyl / Q000737:chemistry*; D004563:Electrochemistry; D009942:Organometallic Compounds / Q000737:chemistry*; D010084:Oxidation-Reduction; D012428:Ruthenium / Q000737:chemistry*; D013059:Spectrum Analysis, Raman; D014867:Water / Q000737:chemistry*
chemical_list: D009942:Organometallic Compounds; D014867:Water; D015082:2,2'-Dipyridyl; D012428:Ruthenium
keywords: Raman spectroscopy; oxidation; peroxido ligands; ruthenium; water splitting