Synthesis and Characterization of Heterodinuclear Ln<sup>3+</sup>−Fe<sup>3+</sup> and Ln<sup>3+</sup>−Co<sup>3+</sup> Complexes, Bridged by Cyanide Ligand (Ln<sup>3+</sup> = Lanthanide Ions). Nature of the Magnetic Interaction in the Ln<sup>3+</sup>−Fe<sup>3+</sup> Complexes
作者:Albert Figuerola、Carmen Diaz、Joan Ribas、Vassilis Tangoulis、Jaume Granell、Francesc Lloret、José Mahía、Miguel Maestro
DOI:10.1021/ic025669g
日期:2003.1.1
The reaction of Ln(NO3)(3).aq with K-3[Fe(CN)(6)] Or K-3[Co(CN)(6)] in N,N'-dimethyltormamide (DMF) led to 25 heterodinuclear [Ln(DMF)(4)(H2O)(3)(mu-CN)Fe(CN)(5)]-nH(2)O and [Ln(DMF)(4)(H2O)(3)(mu-CN)Co(CN)(5)].nH(2)O complexes (with Ln = all the lanthanide(III) ions, except promethium and lutetium). Five complexes (Pr3+-Fe3+), (Tm3+-Fe3+), (Ce3+-Co3+), (Sm3+-Co3+), and (Yb3+-Co3+) have been structurally characterized; they crystallize in the equivalent monoclinic space groups P2(1)/c or P2(1)/n. Structural studies of these two families show that they are isomorphous. This relationship in conjunction with the diamagnetism of the Co3+ allows an approximation to the nature of coupling between the iron(III) and the lanthanide(III) ions in the [Ln(DMF)(4)(H2O)(3)(mu-CN)Fe(CN)(5)]-nH(2)O complexes. The Ln(3+)-Fe3+ interaction is antiferromagnetic for Ln = Ce, Nd, Gd, and Dy and ferromagnetic for Ln = Tb, Ho, and Tm. For Ln = Pr, Eu, Er, Sm, and Yb, there is no sign of any significant interaction. The isotropic nature of Gd3+ helps to evaluate the value of the exchange interaction.