College of Chemical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 210009, P. R. China.
Dalton Trans. 2018 Jul 17;47(28):9504-9511. doi: 10.1039/c8dt01613e.
Three new nickel-cluster-substituted polyoxometalates (POMs), [Ni6(H2O)9(μ3-OH)3(HSiW9O34)]2·12H2O (1), [Ni(en)(H2O)3][Ni6(H2O)3(en)2L(μ3-OH)3(HSiW9O34)]2·9H2O (2) (en = ethylenediamine; L = C7H5O2 = benzoic acid) and [Ni6(L')6(CH3COO)(H2O)3(μ3-OH)3(HPW9O34)]2·9H2O (3) (L' = C5NH5 = pyridine) were successfully isolated under hydro-/solvothermal conditions. 1-3 were structurally characterized by single-crystal XRD, elemental analyses, PXRD, IR, and TGA. Compound 1 mainly consists of a pair of {Ni6SiW9} fragments and some water molecules. Interestingly, the whole structure can be regarded as the connection of {Ni6SiW9} and another unit rotated 180° through Ni-O-W bonds, forming a dimeric structure {Ni6SiW9}2. Compounds 2 and 3 also have an {Ni6XW9}2 (X = Si, P) dimer, but there is a big difference in the connection between {Ni6SiW9} units. On this basis, mono-dentate conjugated organic ligands (benzoic acid (L) and pyridine (L')) were successfully introduced. It is noteworthy that pyridine molecules were first integrated into {Ni6SiW9}-based clusters and 3 features the highest number of organic ligands (six pyridines per Ni6) in the reported {Ni6XW9}-based clusters. The introduction of organic ligands to compounds 2 and 3 can bring about better third-order nonlinear optical properties. Magnetic research indicated the existence of ferromagnetic interactions in 2-3.
三种新型镍簇取代的多金属氧酸盐（POMs），[Ni6(H2O)9(μ3-OH)3(HSiW9O34)]2·12H2O（1），[Ni(en)(H2O)3][Ni6(H2O)3(en)2L(μ3-OH)3(HSiW9O34)]2·9H2O（2）（en = 乙二胺；L = C7H5O2 = 苯甲酸）和[Ni6(L')6(CH3COO)(H2O)3(μ3-OH)3(HPW9O34)]2·9H2O（3）（L' = C5NH5 = 吡啶）在水热/溶剂热条件下成功分离。1-3 通过单晶 XRD、元素分析、PXRD、IR 和 TGA 进行结构表征。化合物 1 主要由一对{Ni6SiW9}片段和一些水分子组成。有趣的是，整个结构可以看作是通过 Ni-O-W 键连接{Ni6SiW9}和另一个单元，形成一个二聚体结构{Ni6SiW9}2。化合物 2 和 3 也具有{Ni6XW9}2（X = Si，P）二聚体，但{Ni6SiW9}单元之间的连接存在很大差异。在此基础上，成功引入了单齿共轭有机配体（苯甲酸（L）和吡啶（L'））。值得注意的是，吡啶分子首次被整合到基于{Ni6SiW9}的簇中，并且 3 具有报道的基于{Ni6XW9}的簇中最多的有机配体（每个 Ni6 有六个吡啶）。化合物 2 和 3 中有机配体的引入可以带来更好的三阶非线性光学性能。磁性研究表明 2-3 中存在铁磁相互作用。
