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Abstract Thesynandantiisomers of [FeIV(O)(TMC)]2+(TMC=tetramethylcyclam) represent the first isolated pair of synthetic non‐heme oxoiron(IV) complexes with identical ligand topology, differing only in the position of the oxo unit bound to the iron center. Both isomers have previously been characterized. Reported here is that thesynisomer [FeIV(Osyn)(TMC)(NCMe)]2+(2) converts into itsantiform [FeIV(Oanti)(TMC)(NCMe)]2+(1) in MeCN, an isomerization facilitated by water and monitored most readily by1H NMR and Raman spectroscopy. Indeed, when H218O is introduced to2, the nascent1becomes18O‐labeled. These results provide compelling evidence for a mechanism involving direct binding of a water moleculetransto the oxo atom in2with subsequent oxo–hydroxo tautomerism for its incorporation as the oxo atom of1. The nonplanar nature of the TMC supporting ligand makes this isomerization an irreversible transformation, unlike for their planar heme counterparts.
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A High‐Valent Manganese(IV)–Oxo–Cerium(IV) Complex and Its Enhanced Oxidizing Reactivity
Abstract A mononuclear nonheme manganese(IV)–oxo complex binding the Ce4+ion, [(dpaq)MnIV(O)]+–Ce4+(1‐Ce4+), was synthesized by reacting [(dpaq)MnIII(OH)]+(2) with cerium ammonium nitrate (CAN).1‐Ce4+was characterized using various spectroscopic techniques, such as UV/Vis, EPR, CSI‐MS, resonance Raman, XANES, and EXAFS, showing an Mn−O bond distance of 1.69 Å with a resonance Raman band at 675 cm−1. Electron‐transfer and oxygen atom transfer reactivities of1‐Ce4+were found to be greater than those of MnIV(O) intermediates binding redox‐inactive metal ions (1‐Mn+). This study reports the first example of a redox‐active Ce4+ion‐bound MnIV‐oxo complex and its spectroscopic characterization and chemical properties.
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- Award ID(s):
- 1900476
- PAR ID:
- 10118060
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Angewandte Chemie International Edition
- Volume:
- 58
- Issue:
- 45
- ISSN:
- 1433-7851
- Page Range / eLocation ID:
- p. 16124-16129
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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