Crystal Structures, Magnetism, and Spectroscopic Properties of One-dimensional Cyanide-bridged Tb(III)/Dy(III)/Ho(III)/Er(III)-Cr(III) Complexes.

Department of Chemistry, Keio University
â—‹Takashiro Akitsu Yasuaki Einaga

Recently, we have discovered the first photo-induced magnetization phenomenon of 3d-4f cyanide-bridged bimetallic assemblies, Ln(DMF)4(H2O)3M(CN)6.H2O (Ln = Nd; M=Fe, Co) [1]. In contrast to conventional photo-induced electron transfer for cyanide-bridged 3d-3d transition metal complexes, the photo-induced magnetization for 3d-4f complexes was suggested to be due to structural distortion of cyanide-bridge ligands as well as lattice strain of the crystals. In order to elucidate the relationship between molecular or crystal structures and their electronic properties, we have developed metal-substituted complexes exhibiting various dimensionality such as bimetallic complexes, one-dimensional chains, and two-dimensional sheets systematically. In the present paper, we will report on new one-dimensional chain structures, magnetism, and IR, electronic, and XPS spectroscopic properties of, Ln(DMF)4(H2O)2Cr(CN)6.H2O (Ln = Tb, Dy, Ho, and Er) complexes.
Because of lanthanoid contraction, four complexes are isostructural in P21/a showing gradual differences in both cell parameters and Ln-N bond lengths or Ln-N-C bond angles. Only Dy and Er complexes could be solved as P21/c, though structural similarity between P21/c and P21/a complexes was proved by powder pattern simulation. The detailed electronic properties in the solid state will be presented later.

[1] G. Li, T. Akitsu, O. Sato, and Y. Einaga, J. Am. Chem. Soc., 125, 12396 (2003).