Tb2, Dy2, and Zn2Dy4 Complexes Showing the Unusual Versatility of a Hydrazone Ligand toward Lanthanoid Ions: a Structural and Magnetic Study.

Three dinuclear complexes, [Tb2(H2daps)2(CH3OH)5.5(H2O)0.5](Cl)2 (Tb2Cl), [Dy2(H2daps)2(Cl)(CH3OH)3(H2O)]Cl (Dy2Cl), and [Dy2(H2daps)2(H2O)6](CF3SO3)2 (Dy2CF3SO3), as well as the heterohexanuclear compound [Zn2Dy4(daps)2(Hdaps)(Cl)3(OH)2(CH3OH)(H2O)5] (Zn2Dy4) (H4daps: 2,6-bis(1-salicyloylhydrazonoethyl)pyridine), which crystallize with different lattice molecules, show their hexa- or heptadentate hydrazone ligands acting with hitherto unknown μ2-κ5:κ1, μ3-κ5:κ4:κ1, μ4-κ5:κ4:κ1:κ1, or μ4-κ5:κ2:κ1:κ1 bridging modes. The single X-ray crystal structures of the dinuclear complexes show nine-coordinated N3 O6 environments for lanthanoid atoms in Tb2Cl and Dy2CF3SO3, with distorted geometries, between spherical capped square antiprism and muffin-like, while the dysprosium atoms in Dy2Cl are eight-coordinated, with distorted triangular dodecahedron geometries. In the case of Zn2Dy4, both eight-coordinated, O8 and O7 Cl, as well as nine-coordinated N3 O6 environments coexist in the crystal structure, with biaugmented trigonal prism, triangular dodecahedron, and muffin-like pseudogeometries. The magnetic study of all the complexes shows that none of the pure samples behaves as a single molecular magnet (SMM) and that the quantum tunnel cannot be removed by dilution of any of the dinuclear complexes, but except in diluted [Y1.904Dy0.096(H2daps)2(Cl)(H2O)4]Cl (Dy2Cl@Y), behaves as a weak field induced SMM. The heterohexanuclear Zn2Dy4 complex also lacks slow relaxation of the magnetization.