Crystal structures of two (3-hydroxy-4-nitrobenzoato) complexes of magnesium(II):: Ionic entities stabilized by stacking interactions and extensive hydrogen bonding

The crystal structures of two Mg(II) complexes of 3-hydroxy-4-nitrobenzoic acid have been reported, The first complex, 2 (C14H20N2O16Mg), consists of ionic entities comprising one hexaaquamagnesium cation and two organic carboxylate anions. The second complex, 3 (C7H15NO11Mg) consists of zwitterionic entities comprising one organic ligand per Mg atom. In both cases, the complexes are linked through an extensive hydrogen bonding network. The 3D supramolecular architectures of these complexes are also stabilized by two types of stacking interactions. An interesting interconversion between the two complexes was observed in aqueous solution. (C) 2008 Elsevier Ltd. All rights reserved.