1-D hydrogen-bonded organization of hexanuclear {3d-4f-5d} complexes: evidence for slow relaxation of the magnetization for [{(LNi)-Ni-Me2(H2O)Ln(H2O)(4.5)}(2){W(CN)(8)}(2)] with Ln = Tb and Dy

Heterometallic {3d-4f-5d} aggregates with formula [{(LNi)-Ni-Me2(H2O)Ln(H2O)4.5}(2){W(CN)(8)}(2)]center dot 15H(2)O, (L-Me2 stands for N,N'-2,2-dimethylpropylenedi(3-methoxysalicylideneiminato) Schiff-base ligand) with Ln = Gd, Tb, Dy, have been obtained by reacting bimetallic [(LNi)-Ni-Me2(H2O)(2)Ln(NO3)(3)] and Cs-3{W(CN)(8)} in H2O. The hexanuclear complexes are organized in 1-D arrays by means of hydrogen bonds established between the solvent molecules coordinated to Ln and the CN ligands of an octacyanometallate moiety. The X-ray structure was solved for the Tb derivative. Magnetic behavior indicates ferromagnetic {W-Ni} and {Ni-Ln} interactions (J(NiW) = 18.5 cm(-1), J(NiGd) = 1.85 cm(-1)) as well as ferromagnetic intermolecular interactions mediated by the H-bonds. Dynamic magnetic susceptibility studies reveal slow magnetic relaxation processes for the Tb and Dy derivatives, suggesting SMM type behavior for these compounds.