A High-Valent Manganese(IV)-Oxo-Cerium(IV) Complex and Its Enhanced Oxidizing Reactivity

A mononuclear nonheme manganese(IV)-oxo complex binding the Ce⁴⁺ ion, [(dpaq)Mn^IV (O)]⁺ -Ce⁴⁺ (1-Ce⁴⁺ ), was synthesized by reacting [(dpaq)Mn^III (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 of 1-Ce⁴⁺ were found to be greater than those of Mn^IV (O) intermediates binding redox-inactive metal ions (1-Mⁿ⁺ ). This study reports the first example of a redox-active Ce⁴⁺ ion-bound Mn^IV -oxo complex and its spectroscopic characterization and chemical properties.