title: Synthesis, crystal structure, and magnetic studies of one-dimensional cyano-bridged Ln3+-Cr3+ complexes with bpy as a blocking ligand.
abstract: The reaction of Ln(NO3)3.aq with K3[Cr(CN)6] and 2,2'-bipyridine (bpy) in a water/ethanol solution led to two families of complexes: 4 one-dimensional (1D) complexes of the formula trans-[Cr(CN)4(mu-CN)2Ln(H2O)3(bpy)2]n.4nH2O.3.5nbpy (Ln3+ = La, Ce, Pr, and Nd) and 10 1D complexes of the formula trans-[Cr(CN)4(mu-CN)2Ln(H2O)4(bpy)]n.3.5nH2O.1.5nbpy (Ln3+ = Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, Yb, and Lu). The structures for the fourteen complexes [LaCr]n (1), [CeCr]n (2), [PrCr]n (3), [NdCr]n (4), [NdCr]n (4'), [SmCr]n (5), [EuCr]n (6), [TbCr]n (7), [DyCr]n (8), [HoCr]n (9), [ErCr]n (10), [TmCr]n (11), [YbCr]n (12), and [LuCr]n (13) have been solved. Complexes 1-4 crystallize in the orthorhombic space group Pbam and are isomorphous; complexes 4'-13 crystallize in the triclinic space group PI and are isomorphous. The X-ray structural characterization of complexes 1-4 shows the presence of a discrete decameric water cluster built around a cyclic hexameric core stabilized by the solid-state structure, which represents another new mode of association of water molecules. The Ln3+-Cr3+ magnetic interaction is negligible in 6 and 12, antiferromagnetic in 2, 4', 7, 8, 9, 10, and 11, and unresolved for 3. The complex 5 is a ferrimagnet because its magnetic studies suggest the onset of a very weak ferromagnetic three-dimensional ordering.
authors.affiliation: Departament de Química Inorgànica, Universitat de Barcelona, Martí i Franquès, 1-11, 08028 Barcelona, Spain.
authors.forename: Marta
authors.initials: M
authors.lastname: Estrader
authors.forename: Joan
authors.initials: J
authors.lastname: Ribas
authors.forename: Vassilis
authors.initials: V
authors.lastname: Tangoulis
authors.forename: Xavier
authors.initials: X
authors.lastname: Solans
authors.forename: Merce
authors.initials: M
authors.lastname: Font-Bardía
authors.forename: Miguel
authors.initials: M
authors.lastname: Maestro
authors.forename: Carmen
authors.initials: C
authors.lastname: Diaz