Sun Juan, Wu Qi, Lu Jiao, Jing Pei, Du Yeshuang, Li Licun
Hubei Key Laboratory of Pollutant Analysis & Reuse Technology, College of Chemistry and Chemical Engineering, Hubei Normal University, Huangshi 435002, P. R. China.
Dalton Trans. 2020 Dec 15;49(47):17414-17420. doi: 10.1039/d0dt03312j.
Three novel lanthanide-biradical complexes {[Ln(hfac)3]2(mbisNITPyPh)(H2O)}{Ln(hfac)3}·CHCl3 (1-Gd; 2-Tb; 3-Dy) were successfully achieved by reacting the biradical mbisNITPyPh (5-(3-pyridyl)-1,3-bis(1-oxyl-3'-oxido-4',4',5',5'-tetramethyl-4,5-hydro-1H-imidazol-2-yl)benzene) with Ln(hfac)3·2H2O (hfac = hexafluoroacetylacetonate). These Ln-biradical complexes consist of two kinds of spin moieties, namely, dinuclear {[Ln(hfac)3]2(mbisNITPyPh)(H2O)} and mononuclear {Ln(hfac)3}, in which two adjacent dinuclear units are linked by intermolecular hydrogen bonds involving the uncoordinated nitroxide units and the coordinated water molecules of Ln ions, forming a cyclic tetranuclear structure unit. The magnetization study reveals that intramolecular Ln(iii)-coordinated NO ferromagnetic interactions are dominant in the present system. Moreover, the clear frequency dependence of ac magnetic susceptibilities of complex 3-Dy is indicative of slow relaxation of magnetization behavior, indicating its single-molecule magnet nature.
通过将双自由基mbisNITPyPh（5-(3-吡啶基)-1,3-双(1-氧基-3'-氧化-4',4',5',5'-四甲基-4,5-氢-1H-咪唑-2-基)苯）与Ln(hfac)3·2H2O（hfac = 六氟乙酰丙酮）反应，成功制备了三种新型镧系双自由基配合物{[Ln(hfac)3]2(mbisNITPyPh)(H2O)}{Ln(hfac)3}·CHCl3（1-Gd；2-Tb；3-Dy）。这些镧系双自由基配合物由两种自旋部分组成，即双核{[Ln(hfac)3]2(mbisNITPyPh)(H2O)}和单核{Ln(hfac)3}，其中两个相邻的双核单元通过涉及未配位的氮氧化物单元和Ln离子配位水分子的分子间氢键相连，形成环状四核结构单元。磁化研究表明，分子内Ln(iii)配位的NO铁磁相互作用在本体系中占主导地位。此外，配合物3-Dy的交流磁化率明显的频率依赖性表明其具有磁化行为的缓慢弛豫，表明其单分子磁体性质。
