[Cu{C2(COO)2}(H2O)3]•H2O, the first copper complex of acetylenedicarboxylic acid

In the title compound, catena-poly[[[triaquacopper(II)]-mu- acetylenedicarboxylato-kappa(2)O:O"] hydrate], {[Cu(C4O4)(H2O)(3)].H2O}(n), the Cu-II ion is coordinated by two monodentate carboxylate groups in trans positions and three water molecules, thus forming a fivefold coordination polyhedron that can be described as a distorted square pyramid. All atoms are located on general sites. The polyhedra are connected by bifunctional acetylenedicarboxylate ligands, to form almost linear chains parallel to [001]. Hydrogen bonds involving the non-coordinated water molecule connect these chains to form a three-dimensional framework.