Synthesis, Structures, and Magnetic Properties of Three Fluoride-Bridged Lanthanide Compounds: Effect of Bridging Fluoride Ions on Magnetic Behaviors

A family of fluoride-bridged lanthanide compounds, [Dy^IIIF­(oda)­(H₂O)₃] (<b>1</b>,<b> oda =</b> oxidiacetate) and [Ln^III₂F₂(oda)₂(H₂O)₂] (Ln = Tb­(<b>2</b>) and Dy­(<b>3</b>)), was synthesized and characterized. To investigate the effects of bridging ligands on magnetic behaviors, two hydroxyl-bridged complexes of formulas [Ln^III₂(OH)₂(oda)₂(H₂O)₄] (Ln = Tb­(<b>4</b>) and Dy­(<b>5</b>)) were also synthesized. Magnetic measurements show that the magnetic behaviors of the compounds are obviously distinct. Compounds <b>1</b>,<b> 2</b>, and <b>3</b> show ferromagnetic interactions, while only antiferromagnetic interactions are observed in compounds <b>4</b> and <b>5</b>. Among these compounds, <b>1</b> and <b>3</b> show frequency-dependent ac-susceptibility indicative of slow magnetic relaxation. Because the structures of Dy₂ cores are very similar in compounds <b>3</b> and <b>5</b>, it may be inferred that the differences of bridging ligands are mainly responsible for the distinct magnetic exchange interactions and relaxation dynamics