RESUMEN
The molecular structures of tetra-aqua-[N,N'-bis-(pyridin-4-yl)pyridine-2,6-dicar-boxamide]-sulfatomanganese(II) dihydrate, [Mn(SO4)(C17H13N5O2)(H2O)4]·2H2O or [Mn(H2L1)(SO4)(H2O)4]·2H2O, (I), and tetra-aqua-bis[N,N'-bis-(pyridin-4-yl)pyridine-2,6-dicar-boxamide]cadmium(II) sulfate tetra-hydrate, [Cd(C17H13N5O2)2(H2O)4]SO4·4H2O or [Cd(H2O)4(H2L1)2]·SO4·4H2O, (II), both contain a central metal atom in a distorted octa-hedral geometry coordinated equatorially by four oxygen atoms from water mol-ecules. In (I), the axial positions are occupied by a nitro-gen atom from H2L1 and an oxygen atom from the sulfate anion, whereas in (II), the axial positions contain two nitro-gen atoms from two different H2L1 ligands and the sulfate anion acts as the charge-balancing ion. π-π stacking between pyridine rings and a network of hydrogen bonds involving the water molecules and the sulfate anions play a crucial role in the mol-ecular self-assembly of the two structures.