10.1021/acsomega.8b00550.s002 Yan Peng Yan Peng Valeriu Mereacre Valeriu Mereacre Christopher E. Anson Christopher E. Anson Annie K. Powell Annie K. Powell Butterfly M<sub>2</sub><sup>III</sup>Er<sub>2</sub> (M<sup>III</sup> = Fe and Al) SMMs: Synthesis, Characterization, and Magnetic Properties American Chemical Society 2018 dc compound OH MeCN Me-PhCO 2 H relaxation SMM H 2 L energy barrier height Fe 2 Er 2 pmide Et 3 N Butterfly M 2 III Er 2 Al 2 Er 2 Me-PhCO 2 Er III ions 2018-06-13 13:31:09 Dataset https://acs.figshare.com/articles/dataset/Butterfly_M_sub_2_sub_sup_III_sup_Er_sub_2_sub_M_sup_III_sup_Fe_and_Al_SMMs_Synthesis_Characterization_and_Magnetic_Properties/6509480 The reaction of <i>N</i>-(2-pyridylmethyl)­iminodiethanol (H<sub>2</sub>L, pmide), FeCl<sub>2</sub>·4H<sub>2</sub>O or AlCl<sub>3</sub>·6H<sub>2</sub>O with ErCl<sub>3</sub>·6H<sub>2</sub>O and <i>p</i>-Me-PhCO<sub>2</sub>H in the ratio of 2:1:1:4 in the presence of Et<sub>3</sub>N in MeOH and MeCN yielded compounds [Fe<sub>2</sub>Er<sub>2</sub>(μ<sub>3</sub>-OH)<sub>2</sub>(pmide)<sub>2</sub>(<i>p</i>-Me-PhCO<sub>2</sub>)<sub>6</sub>]·2MeCN (<b>1</b>) and [Al<sub>2</sub>Er<sub>2</sub>(μ<sub>3</sub>-OH)<sub>2</sub>(pmide)<sub>2</sub>(<i>p</i>-Me-PhCO<sub>2</sub>)<sub>6</sub>]·2MeCN (<b>2</b>). These two complexes are isostructural, possessing a planar butterfly motif with the Er<sup>III</sup> ions in the wingtip positions. Both compounds show single molecule magnet (SMM) behavior. For the [Al<sub>2</sub>Er<sub>2</sub>] compound, the slow relaxation of the magnetization under zero applied direct current (dc) field does not show maxima, but the relaxation processes could be analyzed using an applied dc field of 1000 Oe. In-depth alternating current measurements under different dc fields on the [Fe<sub>2</sub>Er<sub>2</sub>] compound reveals that the Fe–Fe and Fe–Er interactions speed up the relaxation and decrease the energy barrier height of the SMM in comparison with the [Al<sub>2</sub>Er<sub>2</sub>] case.