We report the first example of a mononuclear nonheme manganese(III)-hydroperoxo complex derived from protonation of an isolated manganese(III)-peroxo complex bearing an N-tetramethylated cyclam (TMC) ligand, [Mn(III)(TMC)(OOH)](2+). The Mn(III)-hydroperoxo intermediate is characterized with various spectroscopic methods as well as with density functional theory (DFT) calculations, showing the b...

The oxygen-evolving complex (OEC) of photosystem II contains a Mn(4)CaO(n) catalytic site, in which reactivity of bridging oxidos is fundamental to OEC function. We synthesized structurally relevant cuboidal Mn(3)MO(n) complexes (M = Mn, Ca, Sc; n = 3,4) to enable mechanistic studies of reactivity and incorporation of μ(3)-oxido moieties. We found that Mn(IV)(3)CaO(4) and Mn(IV)(3)ScO(4) were u...

Mn-superoxide dismutase (Mn-SOD), which protects the cell from the toxic potential of superoxide radicals (O(2)(-*)), is the only type of SOD which resides in eukaryotic mitochondria. Up-to-date, the exact catalytic mechanism of the enzyme and the relationship between substrate moieties and the ligands within the active site microenvironment are still not resolved. Here, we set out to explore t...

The five manganese-containing, Keggin-based tungstosilicates [Mn(II)3(OH)3(H2O)3(A-α-SiW9O34)](7-) (1), [Mn(III)3(OH)3(H2O)3(A-α-SiW9O34)](4-) (2), [Mn(III)3(OH)3(H2O)3(A-β-SiW9O34)](4-) (3), [Mn(III)3Mn(IV)O3(CH3COO)3(A-α-SiW9O34)](6-) (4), and [Mn(III)3Mn(IV)O3(CH3COO)3(A-β-SiW9O34)](6-) (5) were synthesized in aqueous medium by interaction of [A-α-SiW9O34](10-) or [A-β-SiW9O34H](9-) with eit...

In this manuscript, we report that a bacterial multicopper oxidase (MCO266) catalyzes Mn(II) oxidation on the cell surface, resulting in the surface deposition of Mn(III) and Mn(IV) oxides and the gradual formation of bulky oxide aggregates. These aggregates serve as nucleation centers for the formation of Mn oxide micronodules and Mn-rich sediments. A soil-borne Escherichia coli with high Mn(I...

Ligand modification transforms a polyoxometalate-anchored cubane-type [Mn(III)(3)Mn(IV)O(4)] core into a centrosymmetric [Mn(III)(6)Mn(IV)O(8)] di-cubane cluster, and restores the slow magnetization relaxation characteristics typical for [Mn(4)O(4)] cubane-based single-molecule magnets.

High initial Mn(II) concentration results in accumulation of a Mn(III) tartrate complex in the growth medium of Phanerochaete chrysosporium. Since Mn(III) is the major oxidant in ligninolysis by manganese peroxidase, the role of accumulated complex should not be neglected when degradation experiments by a crude culture filtrate are performed. To study the Mn(III) complex oxidative potential it ...

The syntheses, structures, and magnetic properties of compounds of formula [Fe(III)(5-Clsal(2)-trien)][Mn(II)Cr(III)(ox)(3)]·0.5(CH(3)NO(2)) (1), [Fe(III)(5-Brsal(2)-trien)][Mn(II)Cr(III)(ox)(3)] (2), and [In(III)(5-Clsal(2)-trien)][Mn(II)Cr(III)(ox)(3)] (3) are reported. The structure of the three compounds, which crystallize in the orthorhombic P2(1)2(1)2(1) chiral space group, presents a 3D ...