Syntheses and crystal structures of three open-frameworks of metal succinates containing a 4,4′-bipyridine ligand

Three new divalent transitional metal succinates with an additional bipy (bipy = 4,4'-bipyridine) ligand have been synthesized by hydrothermal reactions and structurally determined. The structure of [Cu(C4H4O4)(bipy)(H2O)(2)].2H(2)O (1) features a 3D open framework formed by 1D [Cu(bipy)](2+) chains along the diagonal axis of b and -c that are interconnected by Cu(C4H4O4) helixes along the c-axis. The lattice water molecules are located at the cavities of the framework. In Zn(C4H4O4)(bipy) (2), each zinc cation is octahedrally coordinated by two chelate carboxylate groups from two succinates and 2 N atoms from two bipy molecules, and the ZnO4N2 octahedra are interconnected by bridging succinate ligands into a 1D chain along the <0 1 1> direction. Such chains are further linked into a <0 1 1> layer via pi-pi stacking interaction between the pyridine rings. In [Co(bipy)(H2O)(4)] (C4H4O4).4H(2)O (3), each pair of octahedral cobalt(II) ions is bridged by a bipy ligand, resulting in a 1D [Co(bipy)(H2O)(4)](2+) chain, and the succinate ligands and lattice water molecules are sandwiched between two [Co(bipy)(H2O)(4)](2+) chains to form a <0 1 1> layer via hydrogen bonding. The layers are further interconnected into a 3D network via hydrogen bonds among carboxylate oxygen atoms, aqua ligands, and lattice water molecules. (C) 2003 Elsevier Ltd. All rights reserved.