O-O bond formation via radical coupling in a dinuclear iron water oxidation catalyst with high catalytic activity.

The use of iron-based catalysts for the water oxidation reaction is highly attractive due to the high abundance of iron. While many molecular catalysts have been made, most show limited activity and short lifetimes. An exception with higher activity was presented by Thummel and co-workers in 2015. Herein we present a study on the feasibility of the coupling of two O centered radicals originating from the two subunits of the dinuclear catalyst. The reaction pathway includes the oxidation to the active species Fe IV -O-Fe IV but avoids further high potential oxidations which previous mechanistic proposals have relied on.