From Mn( <scp>II</scp> ) ₃ to Mn( <scp>IV</scp> ) ₃ : Controlled Multielectron Oxidation and Hydrocarbon Oxygenation Within a 7‐Dipy Trinuclear Scaffold

ABSTRACT Cooperative multielectron redox chemistry within multinuclear metal clusters underlies some of the most powerful oxidative transformations in biology. Inspired by the tricopper “harnessed oxene” paradigm proposed for particulate methane monooxygenase, we examine whether analogous redox cooperativity can be extended to manganese using the preorganized 7‐Dipy scaffold. A trinuclear Mn(II) 3 complex ( 1 ) was synthesized and structurally validated (via its mixed‐valent analogue 2 ), establishing an acetate‐stitched Mn 3 core capable of electronic communication. Stepwise oxidation with peroxide reagents converts Mn(II) 3 to a mixed‐valent Mn(III) 2 Mn(IV) state, characterized by a well‐resolved 16‐line X‐band EPR signal consistent with an exchange‐coupled S = 1/2 manifold. Under strongly oxidizing, low‐temperature conditions, an additional g eff ≈ 5 resonance and an 11‐line parallel‐mode signal emerge, supporting access to a higher‐valent Mn(IV)‐enriched cluster, tentatively assigned as Mn(IV) 3 with an S = 3/2 ground state. The oxidized Mn 3 framework mediates oxygen‐atom transfer to strong CH bonds. Cyclohexane oxidation proceeds rapidly at room temperature using TBHP, affording cyclohexanol and cyclohexanone with turnover numbers up to 62.5, while even ethane (BDE ≈ 101 kcal mol −1 ) undergoes measurable oxidation. Solvent‐dependent selectivity and rapid reaction onset indicate fast generation of highly reactive Mn–oxo intermediates. Reaction with the spin probe DMPO yields EPR and GC–MS signatures consistent with oxidative ring opening to MNPA‐type products, further supporting the presence of a strongly oxidizing high‐valent Mn species rather than simple radical adduct formation. These results demonstrate controlled accumulation of multiple oxidative equivalents within a single trinuclear manganese scaffold and establish that multimetal redox cooperativity, previously associated with tricopper systems, can be translated to manganese. The 7‐Dipy platform thus provides a structurally defined framework for exploring multinuclear Mn‐driven hydrocarbon oxygenation under mild conditions.