Key Lab of Polyoxometalate Science, Department of Chemistry, Northeast Normal University, Changchun 130024, P. R. China.
Dalton Trans. 2013 Dec 21;42(47):16596-601. doi: 10.1039/c3dt51899j.
The rational self-assembly of mono-lacunary Keggin clusters with 4d and 4f metal salts via a conventional method has yielded two novel polyoxometalate-based 4d-4f heterometallic compounds containing lacunary Keggin anions connected to ten metal atoms: {[Ag{Ag2(H2O)4}{Ln(H2O)6}2H ⊂ {SiW11Ln(H2O)4O39}2]·nH2O (Ln = Ce and n = 7 for 1, Ln = Pr and n = 3 for 2). Their structures were determined by single crystal X-ray diffraction analyses and further characterized by elemental analyses, IR spectra, and thermogravimetric (TG) analyses. A structural feature in 1 and 2 is that each SiW11O39 cluster (SiW11) is connected to ten metals (five Ag(+) and five Ln(3+) cations), representing the highest number of connected metal atoms to any mono-lacunary Keggin anion to date. This large connectivity leads to a structure with a purely inorganic 3D framework with two kinds of channels along the [100] and [010] directions. The magnetic properties of both compounds show the expected magnetic moments (0.8 and 1.6 amu K mol(-1) per Ce(3+) and Pr(3+) ion, respectively) and confirm the presence of isolated Ce(3+) and Pr(3+) ions.
通过常规方法，单核 Keggin 簇与 4d 和 4f 金属盐的理性自组装得到了两个新型的基于多金属氧酸盐的 4d-4f 异金属化合物，其中包含连接到十个金属原子的空缺 Keggin 阴离子：{[Ag{Ag2(H2O)4}{Ln(H2O)6}2H ⊂ {SiW11Ln(H2O)4O39}2]·nH2O（Ln = Ce，n = 7 为 1，Ln = Pr，n = 3 为 2）。它们的结构通过单晶 X 射线衍射分析确定，并通过元素分析、红外光谱和热重（TG）分析进一步表征。在 1 和 2 中，一个结构特征是每个SiW11O39簇（SiW11）连接到十个金属（五个 Ag(+)和五个 Ln(3+)阳离子），这代表了迄今为止连接到任何单核 Keggin 阴离子的最多金属原子。这种大的连接性导致具有沿[100]和[010]方向的两种类型的通道的纯无机 3D 框架结构。两种化合物的磁性性质均表现出预期的磁矩（分别为 0.8 和 1.6 amu K mol(-1)每 Ce(3+)和 Pr(3+)离子），并证实存在孤立的 Ce(3+)和 Pr(3+)离子。
