A Dinuclear Ruthenium-Based Water Oxidation Catalyst: Use of Non-Innocent Ligand Frameworks for Promoting Multi-Electron Reactions

Abstract

Insight into how H 2 O is oxidized to O 2 is envisioned to facilitate the rational design of artificial water oxidation catalysts, which is a vital component in solar-to-fuel conversion schemes. Herein, we report on the mechanistic features associated with a dinuclear Ru-based water oxidation catalyst. The catalytic action of the designed Ru complex was studied by the combined use of high-resolution mass spectrometry, electrochemistry, and quantum chemical calculations. Based on the obtained results, it is suggested that the designed ligand scaffold in Ru complex 1 has a non-innocent behavior, in which metal-ligand cooperation is an important part during the four-electron oxidation of H 2 O. This feature is vital for the observed catalytic efficiency and highlights that the preparation of catalysts housing non-innocent molecular frameworks could be a general strategy for accessing efficient catalysts for activation of H 2 O. Guilty as charged: The mechanistic details associated with a dinuclear Ru complex capable of mediating catalytic H 2 O oxidation are reported (see figure). By using a combination of experimental measurements and quantum chemical calculations, it is suggested that the designed ligand scaffold in the dinuclear Ru complex has a non-innocent behavior, in which metal-ligand cooperation is an important part during the four-electron oxidation of H 2 O.