Crystal structure of μ-4-oxidobenzoato-κ(2) O (1):O (4)-bis­[bis­(1,10-phenanthroline-κ(2) N,N′)copper(II)] bis­(4-hy­droxy­benzoate) 7.5-hydrate

The title hydrated complex, [Cu(2)(C(7)H(4)O(3))(C(12)H(8)N(2))(4)](C(7)H(5)O(3))(2)·7.5H(2)O, is composed of dinuclear Cu(II) complex cations, noncoordinating 4-hy­droxy­benzoate anions and water mol­ecules of crystallization. In the dinuclear complex cation, the Cu(II) ions are bridged by a 4-oxidobenzoate ligand and thus each metal ion is five-coordinated by two chelating 1,10-phenanthroline (phen) mol­ecules and one anionic O atom in a distorted trigonal-bipyramid geometry. In the crystal, aromatic π–π stacking occurs between phen rings of neighbouring dinuclear Cu(II) complex cations, forming two-dimensional supra­molecular systems parallel to (100).