Two pseudo-polymorphic copper-benzene-1,2,4,5-tetra­carboxyl­ate complexes

Two pseudo-polymorphic polymers, poly[ethyl­ene­diammo­nium [[aqua­copper(II)]-[mu]₄-benzene-1,2,4,5-tetra­carboxyl­ato] dihydrate], {(C₂H₁₀N₂)[Cu(C₁₀H₂O₈)(H₂O)]·2H₂O}_n, (I), and poly[ethyl­ene­diammonium [copper(II)-[mu]₄-benzene-1,2,4,5-tetra­carboxyl­ato] 2.5-hydrate], {(C₂H₁₀N₂)[Cu(C₁₀H₂O₈)]·2.5H₂O}_n, (II), contain two-dimensional anionic layers, ethyl­enediammonium (H₂en) cations acting as counter-ions and free water mol­ecules. Although the topological structures of the two anionic layers are homologous, the coordination environments of the Cu^II centres are different. In (I), the Cu^II centre, sitting on a general position, has a square-pyramidal environment. The two independent benzene-1,2,4,5-tetra­carboxyl­ate (btc) anions rest on centres of inversion. The Cu^II cation in (II) is located on a twofold axis in a square-planar coordination. The H₂en cation is on an inversion centre and the btc ligand is split by a mirror plane. Extensive hydrogen-bonding inter­actions between the complexes, H₂en cations and water mol­ecules lead to the formation of three-dimensional supra­molecular structures.

mer-Bis(1,4-dibenzoyl­thio­semi­carb­azidato-[kappa]³O,N,O')cobalt(II)

The title complex, [Co(C₁₅H₁₂N₃O₂S)₂], consists of an octa­hedrally coordinated Co^II ion, with two crystallographically independent 1,4-dibenzoyl­thio­semicarbazidate ligands in a tridentate mer coordination [Co-O = 2.064 (3)-2.132 (3) Å and Co-N = 2.037 (3)-2.043 (3) Å]. There are inter­molecular N-H...S hydrogen bonds involving one ligand and strong [pi]-­[pi] stacking inter­actions involving the other ligand, resulting in a three-dimensional supra­molecular framework. The hydrogen bonds and [pi]-[pi] inter­actions, as well as different intra­molecular aryl-benzamide H-C...H(-N) distances, give rise to a difference in conformation between the two ligands.