Accelerated Oxygen Atom Transfer and C-H Bond Oxygenation by Remote Redox Changes in Fe3Mn-Iodosobenzene Adducts

摘要

We report the synthesis, characterization, and reactivity of LFe3(PhPz)(3)OMn((PhIO)-Ph-s)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, Fe-57 Mossbauer and X-ray absorption spectroscopy provided unique insights into how changes in oxidation state ((Fe2FeMnII)-Fe-III-Mn-II vs. (Fe3MnII)-Mn-III) influence oxygen atom transfer in tetranuclear Fe3Mn 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.