Structural versatility in copper(II) α-hydroxycarboxylate complexes with the twisted ligands 4,4′-dipyridyldisulfide and bis(4-pyridylthio)methane:: From molecular compounds to two-dimensional coordination polymers

Five new complexes, [Cu(L-1)(2)(SS)(2)] (1), [Cu(L-1)(2)(SS)(2)]-H2O (1W(1)), [Cu-2(L-1)(2)(SCS)]center dot H2O (2w(1)), (1)(infinity)[Cu(L-2)(2)-(SS)]center dot 4H2O (3w(1D)), and (2)(infinity)[CU(L-2)(2)(SCS)]center dot 2H(2)O (4w(1D)) (where SS = 4,4'-dipyridyldisulfide, SCS = bis(4-pyridylthio)methane, L-1 = 2-methyllactate, and L-2= glycolate), have been synthesized by the reaction of the SS and SCS ligands with the corresponding copper(II) alpha-hydroxycarboxylates (2- methyllactate and glycolate). The structures of the mononuclear compounds 1 and 1w(1), which could be considered as pseudo-polymorphs, show that the solvent molecules are not innocent partners and play a key role in the supramolecular association. Compound 2w(1) is a discrete dinuclear molecule in which the SCS ligand acts as bridge between the two copper(II) ions. In these three compounds it seems that the presence of the 2-methyllactate ligand prevents. the formation of the expected coordination polymers through the twisted SS and SCS ligands. Compounds 3w(1D) and 4w(1D), which both contain the glycolate ligand, are one- and two-dimensional (1D and 2D) coordination polymers, respectively. In the crystal lattices of the two compounds, two 1D water morphologies are hosted: a treelike chain for 3w(1D) and a staircase T4(2) tape for 4w(1D). In both cases, the dehydration-rehydration processes are investigated.