A new organic-inorganic composite sandwich-type phosphotungstate: Synthesis, crystal structure and properties of [Ni(phen)3]2H6[Ni4(H2O)2(B-α-PW9O34)2] · 4H2O

Abstract

A new organic-inorganic composite sandwich-type phosphotungstate [Ni(phen)3]2H6[Ni4(H2O)2(B-α-PW9O34)2] · 4H2O (I) (phen = 1,10-phenanthroline) has been synthesized by hydrothermal method and characterized by elemental analysis, IR spectrum, thermogravimetry (TG) analysis, X-ray photoelectron spectroscopy (XPS) and X-ray single crystal diffraction. The structural analysis indicates that each structure unit of the compound III consists of two isolated [Ni(phen)3]2+ cations, six protons, one tetra-NiII-substituted sandwich-type [Ni4(H2O)2(B-α-PW9O34)2]10− anion and four crystallization water molecules. In the compound III the cations and the polyanion were linked together through electrostatic interactions and intermolecular forces. XPS measurement indicates that the oxidation state of W and Ni atoms in the compound III are +6 and +2, respectively. TG analysis of the compound III shows two steps of weight loss.