The heterometallic two-dimensional structure in the Ba2[Cu(L)](ClO4)2 · nH2O crystals (L = ethylenediaminetetraacetate, n = 6; L = ethylenediaminetetra-3-propionate, n = 5)

The crystals of Ba2[Cu(Edtp)](ClO4)2 · 5H2O (i) contain the tetragonal-pyramidal complexes of Cu(II) with ethylenediaminetetra-3-propionate ion with one noncoordinated propionate group. The [Cu(Edtp)]2− complex ions and two sorts of the Ba atoms form two-dimensional supramolecular aggregate. Two Ba(1) atoms and one Cu atom form a tetramer by means of the coordinated carboxyl group and a free propionate group. The tetramers are united through the propionate group into ribbons, which are joined by the Ba(2) atoms into the layers. The coordination sphere of each B atom involves four water molecules, including two bridging water molecules. The perchlorate ions are also coordinated by the Ba atoms, one Ba atom acting as a bridge. The structure of the previously studied Ba2[Cu(Edta)](ClO4)2 · 6H2O (II) crystals with the hexadentate ethylenediaminetetraacetate ion is shown to be similar to that of complex I, but in the case of II, the Ba atoms are equivalent as regards the number of the complex anions bound to them.