A novel two-dimensional cobalt(II) complex composed of one-dimensional twisted pair-like chains: poly[[tetraaquabis(μ3-pyridine-2,5-dicarboxylato-κ4N,O2:O5:O5′)dicobalt(II)] dihydrate]

摘要

A novel neutral polymer, {[Co2(C7H3NO4)2(H2O)4]·2H2O}n, was hydrothermally synthesized using pyridine-2,5-dicarboxylate (2,5-PDC2?) as the organic linker. It features a two-dimensional layer structure constructed from one-dimensional {[Co(2,5-PDC)2]2?}n chains interlinked by [Co(H2O)4]+ units. The two CoII cations occupy special positions, sitting on inversion centres. Each 2,5-PDC2? anion chelates to one CoII cation via the pyridine N atom and an O atom of the adjacent carboxylate group, and links to two other CoII cations in a bridging mode via the O atoms of the other carboxylate group. In this way, the 2,5-PDC2? ligand connects three neighbouring CoII centres to form a two-dimensional network. The two-dimensional undulating layers are linked by extensive hydrogen bonds to form a three-dimensional supramolecular structure, with the uncoordinated solvent molecules occupying the interlamellar region.