Abstract:

We have prepared some 3d-4f cyanide-bridged Ln(DMF)₄(H₂O)₃Fe(CN)₆●H₂O complexes (Ln = Ce, Sm, Nd, and Gd; DMF = N,N-dimethylformamide) by substituting isotopes to ² H-substituted H₂O and DMF and ¹⁸O-substituted H₂O (and normal ¹ H- and ¹⁶O-H₂O or ¹ H-DMF). We examined their crystal structures exhibiting negative thermal expansion and compared in view of hydrogen bonds and lanthanide contraction. Magnetic properties and thermal analysis exhibited importance of intermolecular hydrogen bonds in crystal lattice for this behavior. While Fe2p_3/2 and Fe2p_1/2 XAS indicated constant inner shell electron states of low-spin Fe(III) ions.