Designing a new type of magnetic ionic liquid: a strategy to improve the magnetic susceptibility

A new type of magnetic ionic liquid (MIL) with the general formula [Ln(TODGA)(3)][Ln(hfa)(4)](3) (Ln = Tb, Dy, Ho, Er, Tm, Yb; TODGA = N,N,N',N'-tetra(n-octyl)diglycolamide; hfa = 1,1,1,5,5,5-hexafluoroacetylacetone) named as MILs 1-6, containing the same lanthanide ions in the cation and anion has been synthesized and characterized. The values of chi T-M (T = 300 K) for MILs 1-6 are 46.7, 54.2, 52.2, 43.9, 26.7, and 8.7 cm(3) mol(-1) K, respectively, four times higher than those of MILs containing single corresponding lanthanide ions. The magnetic properties of these MILs indicate that it is an effective strategy to improve the magnetic susceptibility by incorporating lanthanide ions in both the cation and anion of ionic liquids.