In the search for rational design of improved water oxidation catalysts, enhanced catalytic activities were reported for single site Ru catalysis with Ru-iodide coordination. As these complexes are not initially capable of proton coupled electron transfer (PCET) and Ru=O formation, a proposal was put forward on the generation of catalytically active 7-coordinate Ru species. We tested this hypothesis by EPR and X-ray spectroscopy and found that [Ru-II(bpy)(tpy)I](+) only serves as a precursor for the formation of [Ru-IV(bpy)(tpy)=O](2+). Upon oxidation with excess of Ce-IV the Ru-I bond quickly dissociates with the formation of [Ru-III(bpy)(tpy)H2O](3+) and [Ru-IV(bpy)(tpy)=O](2+) complexes. The catalytic steady state was composed of 95% [Ru-II(bpy)(tpy)=O](2+) species. Thus, introducing the Ru-I bond into initial catalysts does not serve to improve catalyst design. This manuscript also shows how EXAFS can directly probe transition metal-halogen interaction for in situ catalysis. (C) 2015 Elsevier Inc. All rights reserved.