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A N23– Radical-Bridged Terbium Complex Exhibiting Magnetic Hysteresis at 14 K

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posted on 14.09.2011, 00:00 authored by Jeffrey D. Rinehart, Ming Fang, William J. Evans, Jeffrey R. Long
The synthesis and magnetic properties of three new N23– radical-bridged dilanthanide complexes, {[(Me3Si)2N]2(THF)Ln}2(μ-η22-N2) (Ln = Tb, Ho, Er), are reported. All three display signatures of single-molecule-magnet behavior, with the terbium congener exhibiting magnetic hysteresis at 14 K and a 100 s blocking temperature of 13.9 K. The results show how synergizing the strong magnetic anisotropy of terbium(III) with the effective exchange-coupling ability of the N23– radical can create the hardest molecular magnet discovered to date. Through comparisons with non-radical-bridged ac magnetic susceptibility measurements, we show that the magnetic exchange coupling hinders zero-field fast relaxation pathways, forcing thermally activated relaxation behavior over a much broader temperature range.