A Manganese(V)-Oxo Tetraamido Macrocyclic Ligand (TAML) Cation Radical Complex: Synthesis, Characterization, and Reactivity Studies

Abstract

A mononuclear manganese(V)-oxo complex with tetraamido macrocyclic ligand (TAML), [Mn-V(O)(TAML)](-) (1), is a sluggish oxidant in oxidation reactions. Herein, a mononuclear manganese(V)-oxo TAML cation radical complex, [Mn-V(O)(TAML(+.))] (2), is reported. It was synthesized by reacting [Mn-III(TAML)](-) with 3.0 equivalents of [Ru-III(bpy)(3)](3+) or upon addition of one-electron oxidant to 1 and then characterized thoroughly with various spectroscopic techniques along with DFT calculations. Although 1 is a sluggish oxidant, 2 is a strong oxidant capable of activating C-H bonds of hydrocarbons (i.e., hydrogen atom transfer reaction) and transferring its oxygen atom to thioanisoles and olefins (i.e., oxygen atom transfer reaction).