Tetra-μ2-acetato-diacetatodi-μ3-hydroxido-tetrakis[piperidinecopper(II)] dihydrate

The title complex, [Cu(4)(C(2)H(3)O(2))(6)(OH)(2)(C(5)H(11)N)(4)]·2H(2)O, possesses an unusual inversion-symmetric tetranuclear copper framework, with each Cu(II) atom displaying a square-pyramidal geometry and one additional long Cu···O contact. The four piperidine ligands are terminal, one at each Cu(II) atom, and the two hydroxide ligands are triply bridging. The six acetate ligands exhibit two distinct coordination modes, namely as two monodentate acetates and four bridging acetates that bridge the two inequivalent copper centres. The noncoordinating acetate O atom is involved in intramolecular hydrogen bonding with H atoms from the hydroxide and one piperidine ligand. In addition, extensive intermolecular hydrogen bonding involving the solvent water molecules is observed.