Data_Sheet_1_The Influence of Halide Substituents on the Structural and Magnetic Properties of Fe6Dy3 Rings.pdf

We report the synthesis and magnetic properties of three new nine-membered Fe(III)-Dy(III) cyclic coordination clusters (CCCs), with a core motif of [Fe6Dy3(μ-OMe)9(vanox)6(X-benz)6] where the benzoate ligands are substituted in the para-position with X = F (1), Cl (2), Br (3). Single crystal X-ray diffraction structure analyses show that for the smaller fluorine or chlorine substituents the resulting structures exhibit an isostructural Fe6Dy3 core, whilst the 4-bromobenzoate ligand leads to structural distortions which affect the dynamic magnetic behavior. The magnetic susceptibility and magnetization of 1-3 were investigated and show similar behavior in the dc (direct current) magnetic data. Additional ac (alternating current) magnetic measurements show that all compounds exhibit frequency-dependent and temperature-dependent signals in the in-phase and out-of-phase component of the susceptibility and can therefore be described as field-induced SMMs. The fluoro-substituted benzoate cluster 1 shows a magnetic behavior closely similar to that of the corresponding unsubstituted Fe6Dy3 cluster, with Ueff = 21.3 K within the Orbach process. By increasing the size of the substituent toward 4-chlorobenzoate within 2, an increase of the energy barrier to Ueff = 36.1 K was observed. While the energy barrier becomes higher from 1 to 2, highlighting that the introduction of different substituents on the benzoate ligand in the para-position has an impact on the magnetic properties, cluster 3 shows a significantly different SMM behavior where Ueff is reduced in the Orbach regime to only 4.9 K.

本研究报告了三种新型九元环 Fe(III)-Dy(III) 循环配位簇（CCC）的合成及其磁学性质，其核心结构为 [Fe6Dy3(μ-OMe)9(vanox)6(X-benz)6]，其中苯甲酸配体在间位被 X = F (1)、Cl (2)、Br (3) 取代。单晶X射线衍射结构分析表明，对于较小的氟或氯取代基，所形成的结构展现出等结构的 Fe6Dy3 核心结构，而4-溴苯甲酸配体则导致结构畸变，进而影响其动态磁性行为。对1-3号样品的磁化率和磁化强度进行了研究，其在直流（直流）磁数据中表现出相似的行为。额外的交流（交流）磁测量显示，所有化合物在磁化率的同相和反相分量中均表现出频率依赖性和温度依赖性信号，因此可被描述为场诱导的单分子磁（SMM）。氟取代的苯甲酸簇1表现出与相应的未取代 Fe6Dy3 簇极为相似的磁性行为，在Orbach过程中Ueff = 21.3 K。通过将取代基的尺寸增加到2中的4-氯苯甲酸，观察到Ueff的能量势垒增至36.1 K。尽管从1到2的能量势垒增加，突显了在苯甲酸配体的间位引入不同取代基对磁学性质的影响，但簇3表现出显著不同的SMM行为，在Orbach区域Ueff降低至仅为4.9 K。