High-nuclearity Ni-substituted polyoxometalates: A series of poly(polyoxotungstate)s containing 20-22 nickel centers

Xin Xiong Li, Shou Tian Zheng, Jie Zhang, Wei Hui Fang, Guo Yu Yang*, Juan Modesto Clemente-Juan

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

50 Citations (Scopus)

Abstract

Three high-nuclearity Ni-substituted polyoxotungstates (POTs)-[Ni(enMe) 2(H 2O) 2] 2[Ni(H 2O) 6] 2- [Ni(enMe) 2][Ni(H 2O) 2] 1.5[HNi 20X 4W 34- (OH) 4O 136(H 2O) 6(enMe) 8]·11 H 2O (3), [Ni(en) 2(H 2O)] 2[H 8Ni 21X 4W 34(OH) 4- O 136(en) 10(H 2O) 5]·22 H 2O (4), and [Ni-(enMe) 2] 2[H 6Ni 22X 4W 34(OH) 4O 136(H 2O) 6(enMe) 10]·18 H 2O (5), in which en=ethylenediamine, enMe=1,2-diaminopropane, X=0.5 P+0.5 Ge-were made under hydrothermal conditions and characterized by IR spectroscopy, elemental analysis, thermogravimetric analysis, powder X-ray diffraction, and single-crystal X-ray diffraction. The structures of 3-5 can be viewed as novel derivatives of [H 6Ni 20P 4W 34(OH) 4O 136(enMe) 8- (H 2O) 6]·12 H 2O (1) and [Ni(en) 2- (H 2O)] 2[H 8Ni 20P 4W 34(OH) 4O 136(en) 9- (H 2O) 4]·16 H 2O (2), which both contain 20 nickel ions per structural unit. Compound 3 is the first example of a 1D cluster chain constructed from Ni 20-substituted polyanions [HNi 20X 4- W 34(OH) 4O 136(H 2O) 6(enMe) 8] 11- and [Ni(enMe) 2] 2+ bridges. Compound 4 is a novel cluster-organic chain built by Ni 21-substituted polyanions [H 8Ni 21X 4W 34(OH) 4O 136(en) 10(H 2O) 5] 4- and en molecule bridges. Compound 5 is a discrete POT with 22 Ni centers, and is not only the largest nickel-substituted POT, but also contains the highest number of nickel ions in one polyanion to date. Magnetic measurements illustrate that overall ferromagnetic interactions exist in 1-5. The magnetic behavior of 1 and 2 was theoretically simulated by the MAGPACK magnetic program package. Degradation of multilacunary precursors and the structure-directing effect of trilacunary Keggin {B-α-PW 9O 34} fragments under hydrothermal conditions in the presence of nickel ions result in formation of the largest Ni-substituted poly(polyoxotungstate)s known to date, which contain 20-22 Ni centers. The picture shows the X-ray structure of Ni 22-substituted polyanion [H 6Ni 22X 4W 34(OH) 4O 136(H 2O) 6-(enMe) 10] 4- (enMe=1,2-diaminopropane).

Original languageEnglish
Pages (from-to)13032-13043
Number of pages12
JournalChemistry - A European Journal
Volume17
Issue number46
DOIs
Publication statusPublished - 11 Nov 2011

Keywords

  • hydrothermal synthesis
  • magnetic properties
  • nickel
  • polyoxometalates
  • tungsten

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