Toward synthetic models for high oxidation state forms of the Photosystem II active site metal cluster: the first tetranuclear manganese cluster containing a [Mn4(µ-O)5]6+ coreElectronic supplementary information (ESI) available: Full ORTEP of cation, ESI mass spectrum and 1H NMR spectrum. 3D Picture of the crystal structure. See http://www.rsc.org/suppdata/cc/b1/b111554e/

The first tetrameric high valent manganese complex consisting of a MnIV4(mu-O)5 bridged core, [Mn4(mu-O)5(dmb)4(dmbO)2](ClO4)4, [symbol: see text] was isolated via dimanganese (III,IV) and (IV,IV) intermediates in presence of the oxidant tert-butyl hydroperoxide and was characterized by X-ray crystallography, electrochemistry, infrared, UV-visible, 1H NMR, and mass spectroscopy; the structure found differs greatly from a proposal for the putative Mn4O5 aggregate found in Photosystem II.