# Synthesis, Crystal Structure, and Magnetic Studies of One-Dimensional
Cyano-Bridged Ln^{3+}−Cr^{3+} Complexes with bpy as a Blocking Ligand

journal contribution

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(NO

_{3})_{3}·aq with K_{3}[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)_{2}Ln(H_{2}O)_{3}(bpy)_{2}]*·4*_{n}*n*H_{2}O·3.5*n*bpy (Ln^{3+}= La, Ce, Pr, and Nd) and 10 1D complexes of the formula*trans*-[Cr(CN)_{4}(μ-CN)_{2}Ln(H_{2}O)_{4}(bpy)]*·3.5*_{n}*n*H_{2}O·1.5*n*bpy (Ln^{3+}= 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*P*Ī 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 Ln^{3+}−Cr^{3+}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.