© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim The synthesis, purification, and isolation of mononuclear Ru complexes containing the tridentate dianionic meridional ligand pyridyl-2,6-dicarboxylato (pdc2−) of general formula [RuIII(pdc-κ3-N1O2)(bpy)Cl] (1III) and [RuII(pdc-κ2-N1O1)(bpy)2] (2II) (bpy is 2,2′-bipyridine) is reported. These two complexes and their derivatives were thoroughly characterized through spectroscopic (UV/Vis, NMR) and electrochemical (cyclic voltammetry, differential pulse voltammetry, and coulometry) analyses, and three of the complexes were analyzed by single-crystal X-ray diffraction techniques. Under a high anodic applied potential, both complexes evolve towards the formation of Ru-aquo/oxo derivative species, namely, [RuIII(pdc-κ3-N1O2)(bpy)(OH2)]+ (1-O) and [RuIV(O)(pdc-κ2-N1O1)(bpy)2] (2-O). These two complexes are active catalysts for the oxidation of water to dioxygen and their catalytic activity was analyzed through electrochemical techniques. A maximum turnover frequency (TOFmax)=2.4–3.4×103 s−1 was calculated for 2-O.
- electrochemical characterization
- meridional ligands
- redox catalysis
- Ru complexes
- water oxidation