The reaction of Ln(NO3)3·aq with K3[Fe(CN)6] or K3[Co(CN)6] in N,N′-dimethylformamide (DMF) led to 25 heterodinuclear [Ln(DMF)4(H2O)3(μ-CN)Fe(CN) 5]·nH2O and [Ln(DMF)4(H2O)3(μ-CN)Co (CN)5]·nH2O 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 P21/c or P21/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(μ-CN)Fe (CN)5]·nH2O complexes. The Ln3+-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.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Inorganic Chemistry