Cyano-bridged LnIII/CoIII coordination polymers: synthesis, crystal structure and magnetic properties

Abstract

Heterometallic 3d–4f coordination polymers, [Tb(tpa)(H₂O)₂Co(CN)₆]·EtOH·6H₂O (1Tb) and [Ln(tpa)(H₂O)Co(CN)₆]·2H₂O (Ln = Dy (2Dy) and Er (2Er)), (tpa = tris(2-pyridylmethyl)amine), have been synthesized and structurally characterized. The polymeric structure of [Tb(tpa)(H₂O)₂Co(CN)₆]·EtOH·6H₂O consists of zig-zag chains and solvent water molecules. In the structure of [Ln(tpa)(H₂O)Co(CN)₆]·2H₂O, the chains are interconnected via additional coordination through CN⁻ of Co(CN)₆³⁻, forming a layered architecture. No slow magnetic relaxation is observed for complex 1Tb, while polymers 2Dy and 2Er exhibit field-induced single-molecule magnet behavior. The difference in the ac-magnetic behavior of the obtained complexes is explained by the structure of the coordination environment.