Partial oxidation or disproportionation of tetrameric 2-allyl-6-methylphenoxocopper(I) leads to the formation of a novel trinuclear mixed-valence Cu(I)/Cu(II) alkoxide: [Cu3{OC6H3(CH3)[CH2C(H)![[double bond, length as m-dash]](http://www.rsc.org/images/entities/char_e001.gif)
CH2]}4], in which the central copper(II) atom is coordinated in a distorted square-planar configuration by four oxide ligands, whereas the peripheral copper(I) centres are each bonded to two CC linkages and to two oxide ligands in a tetrahedral arrangement.
