Dinuclear High-Valent Manganese–Oxo Complex with Cyclic Open-Closed Diamond Core for Robust Water Decontamination

High-valent metal-oxo (HVMO) species generated from a homogeneous metal–ligand complex can provide high oxidation power to facilitate selective decontamination. However, sustaining a high reactivity of such a catalytic system is challenging due to the structural fragility of mononuclear-structured organic ligands that are susceptible to self-degradation. Moreover, because of the highly reactive and transient nature of the HVMO complex, its specific structural properties remain unclear, hindering the catalytic mechanism elucidation and system optimization. Here we propose the use of phenanthroline (phen) as a structurally robust alternative ligand for manganese ions (Mn²⁺) complexation and periodate (PI) activation, triggering the formation of a dinuclear Mn-oxo complex, [Mn₂^III,IV(μ-O)₂(phen)₄]³⁺. Impressively, this system achieved rapid sulfamethoxazole oxidation, exhibiting decontamination kinetics 2–5 orders of magnitude higher than those of conventional heterogeneous PI-based systems, and sustained high reactivity for a 10-h continuous operation via a resin-supported complex. Importantly, the structural-stable,diomand-core complex can be directly isolated from the reaction solution. Mechanical study revealed a unique dynamic “closed–open” structure of the Mn₂^III,IV(μ-O)₂ complex for driving pollutant degradation. The system also demonstrated high efficiency and robustness for treating real waters. This study lays a fundamental framework to revolutionize HVMO-based advanced oxidation processes toward sustainable, robust water purification.