Synthesis, Crystal Structure, and Magnetic Studies of One-Dimensional Cyano-Bridged Ln3+−Cr3+ Complexes with bpy as a Blocking Ligand
dataset
posted on 2006-10-02, 00:00 authored by Marta Estrader, Joan Ribas, Vassilis Tangoulis, Xavier Solans, Merce Font-Bardía, Miguel Maestro, Carmen DiazThe 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(μ-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(μ-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 PĪ
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.
