| Polyoxopalladates, as a subarea of POMs, has attracted increasing attention in recent years due to its structural diversity and striking catalysis, which is based on square planar addenda atoms. Polyoxometalates?POMs? exhibit a broad range of physical and chemical propertites having potential applications in different and diverse areas such as materials science, optics, electricity and magnetism. The combination of polyoxopalladates with polyoxotunstate may lead to novel structures and potential propertites. In this paper, according to this strategy, we have dedicated ourselves to preparing three kinds of POMs based on polyoxopalladates via simple one-pot reaction of Pd2+, WO42-, Se O2 with conventional aqueous solution method. The given compounds were fully characterized by X-ray single-crystal diffraction, IR spectroscopy, UV spectroscopy, XRD, electrochemical property, thermogravimetric analyses et.al. In addition we studied the integrity and structural stability in solution by means of electrospray ionization mass spectrometry?ESI-MS?.1. One novel star-shaped polyoxopalladate Na5KH3[Na Pd15?SeO3?10??3-O?10]·18H2O?1? has been gained. Ten selenites occupy the vertices of the nanostar. The fifteen Pd centers form a pentacapped pentagonal prism, which encapsulates an {O10} pentagonal prism occupied by sodium.2. The first example of combination of polyoxopalladate [KPd15?SeO3?10??3-O?10]9- with [H2W12O42]10- leads to the novel compound Na8K4H16[KPd15?SeO3?10??3-O?10]2[H2W12O42]·32H2O?2?. [KPd15?SeO3?10??3-O?10]9- unit is star-shaped and coordinated with four [H2W12O42]10- fragments via Na-O and K-O. Meanwhile, [H2W12O42]10- links with eight [KPd15?SeO3?10??3-O?10]9- units via Na-O and K-O to form a truncated cube.3. The incorporation of transitional metal-substituted polyoxopalladates [M{Pd12?SeO3?8??4-O?8}]6-?M = Co, Zn? into Keggin polyanion [MW12O40]6-?M = Co, Zn? gets two nanoclusters Na18[Co{Pd12?Se O3?8??4-O?8}](Co W12O40)2·48H2O?3? and Na18[Zn{Pd12?Se O3?8??4-O?8}](Zn W12O40)2·61H2O?4? by a one-pot reaction of Pd2+, WO42-, Se O2 with respective transitional metals. [M{Pd12?Se O3?8??4-O?8}]6- unit resembles a three layers of Russian Matryoshka doll, and further encapsulated by {Na18} clusters to form four layers of Russian doll. {Na18} clusters form a tetradecahedron. The eighteen sodiums occupy the vertices of it and every chance is 0.75. [M{Pd12?Se O3?8??4-O?8}]6- unit bond to eight [MW12O40])6- fragments via ?2-O and each [MW12O40]6-links with four [M{Pd12?Se O3?8??4-O?8}]6- units. In addition, the two compounds are stable in the solid state under air and light and show excellent electrochemical behaviors. |
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