Bis(3-amino­pyrazine-2-carboxyl­ato-κ²N¹,O)di­aqua­nickel(II) dihydrate

In the title compound, [Ni(C₅H₄N₃O₂)₂(H₂O)₂]·2H₂O, the Ni^II ion lies on an inversion center and is coordinated in an slightly distorted octa­hedral environment by two N,O-chelating 3-amino­pyrazine-2-carboxyl­ate (APZC) ligands in the equatorial plane and two trans-axial aqua ligands. In the crystal, O—H...O, N—H...O and O—H...N hydrogen bonds involving the solvent water mol­ecules, aqua and APZC ligands form layers parallel to (010). These layers are linked further via O—H...O, N—H...O and C—H...O hydrogen bonds involving the axial aqua ligands, amino groups and the carboxyl­ate groups of the APZC ligands, forming a three-dimensional network.

(Adipato-κ²O,O′)di­aqua­[bis­(pyridin-2-yl-κN)amine]­cobalt(II) trihydrate

In the monomeric title complex, [Co(C₆H₈O₄)(C₁₀H₉N₃)(H₂O)₂]·3H₂O, the distorted octa­hedral CoN₂O₄ coordination environment comprises two N-atom donors from the bidentate di­pyridyldi­amine ligand, two O-atom donors from one of the carboxyl­ate groups of the bidentate chelating adipate ligand and two water mol­ecules. In addition, there are three solvent water mol­ecules which are involved in both intra- and inter-unit O—H...O hydrogen-bonding inter­actions, which together with an amine–water N—H...O hydrogen bond produce a three-dimensional framework.