Two new polyoxovanadates (Co-(N3C5H15)(2))(2)[{ Co(N3C5H15)(2)}V15Sb6O42(H2O)center dot 5H(2)O (1) and (Ni(N3C5H15)(2))(2) [{Ni(N3C5H15)(2)} V15Sb6O42(H2O)]center dot 8H(2)O (2) (N3C5H15 = N-(2-aminoethyl)-1,3-propanediamine) were synthesized under solvothermal conditions and structurally characterized. In both structures the [V15Sb6O42(H2O)](6-) shell displays the main structural motif, which is strongly related to the {V18O42} archetype cluster. Both compounds crystallize in the triclinic space group P (1) over bar with a = 14.3438(4), b = 16.6471(6), c = 18.9186(6) angstrom, alpha = 87.291(3)degrees, beta = 83.340(3)degrees, gamma = 78.890(3)degrees, and V = 4401.4(2) angstrom(3) (1) and a = 14.5697(13), b = 15.8523(16), c = 20.2411(18) angstrom, alpha = 86.702(11)degrees, beta = 84.957(11)degrees, gamma = 76.941(11)degrees, and V = 4533.0(7) angstrom(3) (2). In the structure of 1 the [V15Sb6O42(H2O)](6-) cluster anion is bound to a [Co(N3C5H15)(2)](2+) complex via a terminal oxygen atom. In the Co2+-centered complex, one of the amine ligands coordinates in tridentate mode and the second one in bidentate mode to form a strongly distorted CoN5O octahedron. Similarly, in compound 2 an analogous NiN5O complex is joined to the [V15Sb6O42(H2O)](6-) anion via the same attachment mode. A remarkable difference between the two compounds is the orientation of the noncoordinated propylamine group leading to intermolecular Sb center dot center dot center dot O contacts in 1 and to Sb center dot center dot center dot N interactions in 2. In the solid-state lattices of 1 and 2, two additional [M(N3C5H15)(2)](2+) complexes act as countercations and are located between the [{M(N3C5H15)(2)}V15Sb6O42(H2O)](4-) anions. Between the anions and cations strong N-H center dot center dot center dot O hydrogen bonds are observed. In both compounds the clusters are stacked along the b axis in an ABAB fashion with cations and water molecules occupying the space between the clusters. Magnetic characterization demonstrates that the Ni2+ and Co2+ cations do not significantly couple with the S = 1/2 vanadyl groups. The susceptibility data can be successfully reproduced assuming a distorted ligand field for the Co2+ ions (1) and an O-h-symmetric Ni2+ ligand field (2).