Structure of compound 3
figure3:
The neighboring chains wereinter linked by [Niห้องสมุดไป่ตู้enMe)2]2+bridges to from a 2D layer(d)
Color codes:
WO6 =red, NiO6 and NiO4N2:green, PO4 =yellow
figure4
For compounds 1–3, the good accordance between the experimental and simulated powder XRD patterns indicates the good phase purity of the samples.
TG curve
figure1
1
figure2
figure2:
a) View of the stacking fashion of Dawson polyanions in 1 along the a axis; b) View of the stacking fashion of Dawson polyanions in 2 along the c axis.
Hydrothermal Combination of Trilacunary Dawson Phosphotungstates and Hexanickel Clusters: From an Isolated Cluster to a 3D Framework
Xin-Xiong Li,[a]Wei-Hui Fang,[a]Jun-Wei Zhao,*[b]and Guo-Yu Yang*[a, c] Fujian Institute of Research on the Structure of Matter Chem. Eur. J. 2014, 20,1–10
Synthesis of compound 1
Synthesis of compound 2,3
Structure of compound 1,2
figure1: en=ethylenediamine, enMe=1,2-diaminopropane, Ac=CH COO-
Color codes: WO6 :red, PO4 :yellow, NiO6/NiO2N2(H2O)2 :green
(1)[Ni6(en)3(H2O)6(OH)3(H3P2W15O56)]·14H2O
(2)[Ni(enMe)2(H2O)][Ni6(enMe)3(OH)3(H2O)6(HP2W15O5 6)]·10H2O
(3)[Ni(enMe)2]3[Ni(enMe)2(H2O)][Ni(enMe)(H2O)2][Ni6( enMe)3(OH)3(Ac)2(H2O)(P2W15O56)]2·6H2O
Conclusion
This study provides not only a valuable molecular model of the “Co−Pi” catalysts with a well-defined structure but also an unprecedented opportunity to fine-tune high-nuclearity POM clusters for visible light-driven watersplitting. Their photocatalytic water oxidation activities have been systematically investigated and showed that 1−4 are all effective molecular catalysts and the photocatalytic performance is 3 ≤ 1 < 4 < 2 under visible light irradiation. As 1−4 are a series of Si-centered, Gecentered, P-centered, and As-centered POMs with analogous structure, the comparison of the catalytic activity among 1−4 for water oxidation provides valuable insight into the influence of heteroatoms on oxygen evolution as well as the further design and synthesis of more stable and efficient WOCs. Multiple experiments collectively confirmed that compounds 1−4 are genuine molecular catalysts and maintain their structural integrity under the photocatalytic conditions.
figure 3
Figure 4:
Temperature dependence of the molar
magnetic susceptibility
and the
product of the molar magnetic
susceptibility and the temperature
for compound 3 between 2.0 and 300 K.
Introduction
The design and synthesis of novel transition-metalsubstituted polyoxometalate (TMSP) clusters based on the classical lacunary Keggin or Dawson fragments have raised extreme interest due to their structural varieties and unexpected properties,which gives rise to potential applications in magnetism, material sciences,catalysis,and biomedicine..Three novel hexaNi-substituted Dawson phosphortungstateshave been made under hydrothermal conditions and were characterized by IR spectroscopy, elemental analysis, diffuse reflectance spectroscopy, thermogravimetric analysis, powder X-ray diffraction, and single-crystal X-ray diffraction.