Wang Hui-Sheng, Yang Feng-Jun, Long Qiao-Qiao, Huang Zhi-Yong, Chen Wei, Pan Zhi-Quan, Song You
School of Chemistry and Environmental Engineering, Wuhan Institute of Technology, Key Laboratory for Green Chemical Process of Ministry of Education, Wuhan 430074, P. R. China.
State Key Laboratory of Coordinate Chemistry, Nanjing National Laboratory of Microstructures, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, P. R. China.
Dalton Trans. 2016 Nov 15;45(45):18221-18228. doi: 10.1039/c6dt02945k.
We report the syntheses, crystal structures, and magnetic properties of two 3d-4f heterometallic compounds; namely, [MnLnO(OH){(py)CO}(teaH)(CHCOO)]·6CHCN·2HO (Ln = Dy (1), Tb (2); (py)COH = the gem-diol form of di-2-pyridyl ketone, teaH = triethanolamine). Both compounds were prepared by the reaction of Mn(OAc)·4HO, Ln(NO)·5HO (Ln = Dy and Tb) with the ligands di-2-pyridyl ketone and triethanolamine in MeCN, and they crystallize in the monoclinic space group C2/c. [MnLn] complexes have not been reported before, and the metallic cores of both complexes were unprecedented. In these cores, two Dy or Tb and two Mn ions comprised a well-known butterfly topology, with three of the remaining six Mn atoms each being situated on either side of the butterfly, linked through two μ-O ions. Six Mn and two Mn were in six-coordinated distorted octahedrons and two Ln ions were in nine-coordinated distorted muffins. Interestingly, the coordination sites of Ln ions are occupied by six O and two N atoms from two teaH ligands and one μ-O atom, without the presence of coordinated solvent molecules such as HO and small anions such as NO ions, which is rare in 3d-4f complexes. Remarkably, alternating current (ac) magnetic susceptibility measurements revealed that both complexes displayed dynamic anisotropic magnetic behaviour. The effective energy barrier (U) of complex 2 was estimated to be 18.97 K through high frequency (111-9111 Hz) ac susceptibility measurements. The low symmetry of the coordination configuration of Ln in 1 and 2 may be responsible for the small energy barriers of these two compounds.
我们报道了两种3d-4f异金属化合物的合成、晶体结构和磁性；即，[MnLnO(OH){(py)CO}(teaH)(CHCOO)]·6CHCN·2HO（Ln = Dy（1），Tb（2）；(py)COH = 二-2-吡啶基酮的偕二醇形式，teaH = 三乙醇胺）。这两种化合物均通过Mn(OAc)·4HO、Ln(NO)·5HO（Ln = Dy和Tb）与配体二-2-吡啶基酮和三乙醇胺在乙腈中反应制备，它们结晶于单斜空间群C2/c。此前尚未报道过[MnLn]配合物，且两种配合物的金属核均前所未有的。在这些核中，两个Dy或Tb以及两个Mn离子构成了一种熟知的蝴蝶拓扑结构，其余六个Mn原子中的三个分别位于蝴蝶的两侧，通过两个μ-O离子相连。六个Mn和两个Mn处于六配位扭曲八面体中，两个Ln离子处于九配位扭曲松饼状结构中。有趣的是，Ln离子的配位位点被来自两个teaH配体的六个O和两个N原子以及一个μ-O原子占据，不存在诸如HO等配位溶剂分子和诸如NO离子等小阴离子，这在3d-4f配合物中较为罕见。值得注意的是，交流（ac）磁化率测量表明这两种配合物均表现出动态各向异性磁行为。通过高频（111 - 9111 Hz）ac磁化率测量，配合物2的有效能垒（U）估计为18.97 K。1和2中Ln配位构型的低对称性可能是这两种化合物能垒较小的原因。
