Base- and anion-regulated synthesis of dysprosium compounds

Abstract

Three related Dy(III)-based compounds: [Dy(TPA)(NO₃)₃] (1), [Dy₂(μ-OH)₂(TPA)₂Cl₂(MeOH)₂][Cl₂] (2) and [Dy₂(μ-OH)₂(TPA)₂(TfO)₂(H₂O)₂][TfO]₂ (3) (TPA = tris(2-pyridylmethyl)amine, TfO = trifluoromethanesulfonate) were synthesized based on the tris(2-pyridylmethyl)amine ligand, which could be regulated by the anions of the dysprosium salts and base, indicating the delicate effect of the anions and base on the assembling of Ln(III) compounds. Magnetic investigations indicate that compound 2 is a field-induced single-molecule magnet with U_eff = 35 K and a pre-exponential factor τ₀ = 1.1 × 10⁻⁶ s, whereas compounds 1 and 3 are not single-molecule magnets even under an applied DC field. Although compounds 2 and 3 are very similar, the difference in their magnetic properties are probably due to the different coordination enviroments and geometries of Dy(III) ions caused by the different coordination anions and solvents.