Photoinduced magnetization of the cyano-bridged 3d-4f heterobimetallic assembly Nd(DMF)4(H2O)3(mu-CN)Fe(CN)5.H2O (1) (DMF = N,N-dimethylformamide) is described in this paper. The chiMT values are enhanced by about 45% after UV light illumination in the temperature range of 5-50 K. We propose that UV light illumination induces a structural distortion in 1. This small structural change is propagated by molecular interactions in the inorganic network. Furthermore, the cooperativity resulting from the molecular interaction functions to increase the activation energy of the relaxation processes, which makes observation of the photoexcited state possible. The flexible network structure through the hydrogen bonds in 1 plays an essential role for the photoinduced phenomenon. This finding may open up a new domain for developing the molecule-based magnetic materials.
Svendsen, Helle; Overgaard, Jacob; Chevallier, Marie, Angewandte Chemie - International Edition, 2009, vol. 48, p. 2780 - 2783
作者:Svendsen, Helle、Overgaard, Jacob、Chevallier, Marie、Collet, Eric、Iversen, Bo B.
DOI:——
日期:——
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
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.