A fast metal–metal bonded water oxidation catalyst

• Diruthenium tetraacetate is a fast homogeneous water oxidation catalyst (WOC).
• Its limiting rate for oxygen evolution is 77 s−1, second fastest reported in Ru chemistry.
• It is the first metal–metal bonded WOC.
• This catalyst exhibits high activity in a wide pH range.
• The mechanism operates through a single-site and explains the fast kinetics.

The metal–metal bonded diruthenium (II, II) tetraacetate compound, [Ru2(μ-O2CCH3)4], is a water oxidation catalyst (WOC) that exhibits oxygen evolution rates as high as 77 s−1 at ambient conditions, exhibiting comparable catalytic activity over a wide pH range (1 < pH < 10). The turnover conditions of the catalyst remain active for several hours with oxidative deactivation eventually occurring at a slow rate. DFT calculations support a single-site mechanism via water nucleophilic attack, with the most energy demanding process being the very first one electron oxidation step. This is one of the fastest WOCs reported, and the first WOC found in the field of metal–metal bonded chemistry.

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