A MnIII2FeII chain with a [–MnIII–(OPh)2–MnIII–ON–FeII–NO–] repeat unit was synthesized via the assembling reaction of MnIII salen-type dimers and FeII pyridyloximate complexes, where the –(OPh)– and –ON– bridges represent a biphenolate bridge and an oximate bridge, respectively. The bulky counter anions, BPh4−, which surround the chain to form a zeolite-like brick wall, successfully isolate the chains from a magnetic point of view. This compound is isostructural with Mn2Ni–BPh4, which is an SCM with ST = 3 (H. Miyasaka, A. Saitoh, M. Yamashita and R. Clérac, Dalton Trans., 2008, 2422). Because the FeII unit is diamagnetic, the MnIII dimer, which has the potential to be a single-molecule magnet (SMM), is nearly magnetically isolated, although a weak antiferromagnetic interaction with J/kB ≈ −0.1 K is perturbed between the MnIII dimers with ST = 4 via the FeII unit. Ac susceptibility data shows that two types of relaxation of the magnetization are present, which are attributed to SMM and chain relaxations.
通过 MnIII 萨仑型二聚体和 FeII
吡啶肟络合物的组装反应,合成了具有 [-MnIII-(OPh)2-MnIII-ON-FeII-NO-] 重复单元的 MnIII2FeII 链,其中 -(OPh)- 桥和 -ON- 桥分别代表双
酚桥和
肟桥。笨重的反阴离子 BPh4- 环绕在链周围,形成类似
沸石的砖墙,从磁性角度成功地隔离了链。这种化合物与 Mn2Ni-BPh4 结构相同,后者是 ST = 3 的单片机(H. Miyasaka, A. Saitoh, M. Yamashita and R. Clérac,Dalton Trans.,2008, 2422)。虽然 ST = 4 的 MnIII 二聚体之间通过 FeII 单元存在 J/kB ≈ -0.1 K 的微弱反
铁磁相互作用,但由于 FeII 单元是二磁性的,因此有可能成为单分子磁体 (
SMM) 的 MnIII 二聚体几乎是磁孤立的。电感数据显示存在两种类型的磁化弛豫,分别归因于
SMM 和链弛豫。