The new three-dimensional supramolecule bis{mu-2-[(4-hydroxybenzoyl)hydrazonomethyl]phenolato}bis[aquacopper(II)] dinitrate.

In the title centrosymmetric binuclear complex, Cu(2)(C(14)H(11)N(2)O(3))(2)(H(2)O)(2)(2), the two metal centres are bridged by the phenolate O atoms of the ligand, forming a Cu(2)O(2) quadrangle. Each Cu atom has a distorted square-pyramidal geometry, with the basal donor atoms coming from the O,N,O'-tridentate ligand and a symmetry-related phenolate O atom. The more weakly bound apical donor O atom is supplied by a coordinated water molecule. When a further weak Cu...O interaction with the 4-hydroxy O atom of a neighbouring cation is considered, the extended coordination sphere of the Cu atom can be described as distorted octahedral. This interaction leads to two-dimensional layers, which extend parallel to the (100) direction. The two-dimensional polymeric structure contrasts with other reported structures involving salicylaldehyde benzoylhydrazone ligands, which are usually discrete mono- or dinuclear Cu complexes. The nitrate anions are involved in a three-dimensional hydrogen-bonding network, featuring intermolecular N-H...O and O-H...O hydrogen bonds.