Three oxo complexes with a tetranuclear [Cu(4)(mu(2)-Cl)(6)(mu(4)-O)] unit.

The three title compounds, namely 4-phenyl-1H-imidazolium hexa-mu(2)-chloro-chloro-mu(4)-oxo-tris(4-phenyl-1H-imidazole-kappaN(1))tetracopper(II) monohydrate, (C(9)H(9)N(2))[Cu(4)Cl(7)O(C(9)H(8)N(2))(3)]xH(2)O, hexa-mu(2)-chloro-mu(4)-oxo-tetrakis(pyridine N-oxide-kappaO)tetracopper(II), [Cu(4)Cl(6)O(C(5)H(5)NO)(4)], and hexa-mu(2)-chloro-tetrakis(2-methyl-1H-imidazole-kappaN(1))-mu(4)-oxo-tetracopper(II) methanol trisolvate, [Cu(4)Cl(6)O(C(4)H(6)N(2))(4)]x3CH(4)O, exhibit the same Cu(4)OCl(6) framework, where the O atom at the centre of an almost regular tetrahedron bridges four copper cations at the corners. This group is in turn surrounded by a Cl(6) octahedron, leading to a rather globular species. This special arrangement of the Cu(II) cations results in a diversity of magnetic behaviours.