New Cyanido-Bridged Heterometallic 3d-4f 1D Coordination Polymers: Synthesis, Crystal Structures and Magnetic Properties

Three new 1D cyanido-bridged 3d-4f coordination polymers, {[Gd(L)(H2O)2Fe(CN)6]·H2O}n (1GdFe), {[Dy(L)(H2O)2Fe(CN)6]·3H2O}n (2DyFe), and {[Dy(L)(H2O)2Co(CN)6]·H2O}n (3DyCo), were assembled following the building-block approach (L = pentadentate bis-semicarbazone ligand resulting from the condensation reaction between 2,6-diacetyl-pyridine and semicarbazide). The crystal structures consist of crenel-like LnIII-MIII alternate chains, with the LnIII ions connected by the hexacyanido metalloligands through two cis cyanido groups. The magnetic properties of the three complexes have been investigated. Field-induced slow relaxation of the magnetization was observed for compounds 2DyFe and 3DyCo. Compound 3DyCo is a new example of chain of Single Ion Magnets.