Preparation and StructuralCharacterization of RuII‐DMSO and RuIII‐DMSO‐substituted α‐Keggin‐type Phosphotungstates, [PW11O39RuIIDMSO]5– and [PW11O39RuIIIDMSO]4–, and Catalytic Activity for Water Oxidation

Abstract

AbstractRuII‐ and RuIII‐substituted α‐Keggin‐type phosphotungstates with a dimethyl sulfoxide (DMSO) ligand, [PW11O39RuIIDMSO]5– (1) and [PW11O39RuIIIDMSO]4– (2), were synthesized. Compound 1 was prepared by reaction of [PW11O39]7– with [RuII(DMSO)4]Cl2 in water at 125 °C under hydrothermal conditions and was isolated as a cesium salt. Compound 2 was prepared by reaction of 1 with bromine in water at 60 °C and was isolated as a cesium salt. The compounds were characterized by cyclic voltammetry, elemental analysis, UV/Vis, IR,31P NMR, 183W NMR, 1H NMR, and XANES (Ru K‐edge and L3‐edge)spectroscopic methods. Single crystal structural analysis of 1 revealed that RuII is incorporated in the α‐Keggin framework and coordinated by DMSO through a Ru–S bond. Cyclic voltammetry of 1 indicated that the incorporated RuII‐DMSO is reversibly oxidizable to the RuIII‐DMSO derivative 2. Compound 1 showed catalytic activity for water oxidation in the presence of cerium ammonium nitrate as an oxidant.