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]

Abstract

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−}nchains interlinked by [Co(H2O)4]+units. The two CoIIcations occupy special positions, sitting on inversion centres. Each 2,5-PDC2−anion chelates to one CoIIcationviathe pyridine N atom and an O atom of the adjacent carboxylate group, and links to two other CoIIcations in a bridging modeviathe O atoms of the other carboxylate group. In this way, the 2,5-PDC2−ligand connects three neighbouring CoIIcentres 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.