[Co(H₂O)₆]{[Co(C₄H₄N₂)(H₂O)₂][V₂O₂(pmida)₂]}·2H₂O [H₄pmida is N-(phosphono­meth­yl)imino­diacetic acid]: the first two-dimensional hybrid framework containing [V₂O₂(pmida)₂]⁴⁻ building blocks

The crystal structure of the title compound, polymeric hexa­aqua­cobalt(II) diaqua­dioxodi-μ₂-pyrazine-bis­[μ₃-N-(phos­phono­meth­yl)imino­diacetato]cobalt(II)divanadate(IV) dihydrate, {[Co(H₂O)₆][CoV₂(C₃H₄O₈P)₂(C₄H₄N₂)₂(H₂O)₂]·2H₂O}_n, is the first example of a two-dimensional hybrid framework containing centrosymmetric dimeric [V₂O₂(pmida)₂]⁴⁻ anionic units [H₄pmida is N-(phosphono­meth­yl)imino­diacetic acid]. The structure contains two crystallographically unique cobalt(II) centres, both located at inversion centres and exhibiting Jahn–Teller-distorted octa­hedral coordination geometries. One Co²⁺ cation establishes physical links between adjacent [V₂O₂(pmida)₂]⁴⁻ anionic units, forming one-dimensional anionic ribbons which run along the [010] direction, {[Co(H₂O)₂][V₂O₂(pmida)₂]}_n²ⁿ⁻. Pyrazine ligands, with their centroids located at inversion centres, bridge the above-mentioned Co²⁺ centres, forming {[Co(H₂O)₂][V₂O₂(pmida)₂]}_n²ⁿ⁻ anionic layers which alternate along the [001] direction with [Co(H₂O)₆]²⁺ cations and the water mol­ecules of crystallization. An extensive and highly directional hydrogen-bonded network inter­connects the structural components.