Diaquabis(quinoxaline‐2‐carboxylato‐κ2N1,O)copper(II)

In the title compound, [Cu(C₉H₅N₂O₂)₂(H₂O)₂], the Cu^II ion lies on an inversion centre and has an elongated centrosymmetric octahedral environment, equatorially trans‐coordinated by two N,O‐bidentate quinoxaline‐2‐carboxylate ligands and axially coordinated by two water O atoms. Symmetry‐related molecules are linked by strong O—H...O hydrogen bonds, involving the uncoordinated carboxyl O atom of the carboxylate group and the coordinated water molecules, to form a two‐dimensional network. Weak intermolecular C—H...N interactions also stabilize the crystal structure.     

Diaquabis(propane-1,2-diamine-N,N′)nickel(II) bis(p-toluenesulfonate)

The crystal structure of the title compound, [Ni(C₃H₁₀N₂)₂(H₂O)₂](C₇H₇O₃S)₂ or [Ni(H₂O)₂{NH₂CH₂CH­(NH₂)CH₃}₂](CH₃C₆H₄SO₃)₂, exhibits a layered structure in which the complex cations and the p-toluene­sulfonate anions form alternating layers. The central Ni^II atom of the cation resides on a crystallographic inversion centre and has a slightly distorted octahedral coordination composed of the water ligands bonding through oxy­gen in a trans arrangement and the N,N′-bidentate propane­di­amine ligands. The p-toluene­sulfonate anions are arranged with the sulfonate groups turned alternately towards opposite sides of the layers. The structure of the layers is stabilized by a network of hydrogen bonds between the sulfonate O atoms, water mol­ecules and the propane­di­amine N atoms.