Cobalt and nickel oxide architectures in metal carboxylate frameworks:: From coordination polymers to 3D inorganic skeletons

This microreview is devoted to the synthesis and properties of nickel and cobalt polycarboxylates, which are classified in terms of the geometries of the organic moieties. It is divided into three main sections-dicarboxylates, tricarboxylates and tetra- and hexacarboxylates-and discusses the extreme diversity of these architectures. Numerous topologies can be obtained, ranging from coordination polymers to 3D inorganic skeletons. This microreview begins with the widely studied cobalt succinate system, for which, to date, seven compounds have been reported. Then, examples from malonate to pimelate illustrate the influence of the length of the organic ligand, whereas examples from fumarate to diphen- ate illustrate the effects of rigidity and complexity. In the same way, examples from trimesate to mellitate show the effects of "multiconnecting" organic partners. These latter seem to disadvantage metal oxide condensation, since the two 3D inorganic frameworks contain linear dicarboxylate ions. On the other hand, 3D nickel oxide skeletons seem to be easier to synthesise than cobalt ones. Moreover, under similar hydrothermal conditions, using cobalt and nickel generally leads to different architectures. (c) Wiley-VCH Verlag GmbH & Co.