Accelerated Oxygen Atom Transfer and C-H Bond Oxygenation by Remote Redox Changes in Fe3 Mn-Iodosobenzene Adducts.

We report the synthesis, characterization, and reactivity of [LFe3 (PhPz)3 OMn(s PhIO)][OTf]x (3: x=2; 4: x=3), where 4 is one of very few examples of iodosobenzene-metal adducts characterized by X-ray crystallography. Access to these rare heterometallic clusters enabled differentiation of the metal centers involved in oxygen atom transfer (Mn) or redox modulation (Fe). Specifically, 57 Fe Mössbauer and X-ray absorption spectroscopy provided unique insights into how changes in oxidation state (FeIII2 FeII MnII vs. FeIII3 MnII ) influence oxygen atom transfer in tetranuclear Fe3 Mn clusters. In particular, a one-electron redox change at a distal metal site leads to a change in oxygen atom transfer reactivity by ca. two orders of magnitude.