Hydrothermal synthesis, structure and properties of a new phosphomolybdate based on novel [Co(H2O)4(HP2Mo5O23)]8- anions and [H8(H2O)16]8+ water cluster cations

Abstract

A pure inorganic {P2Mo5O23}6– based cobalt complex [H8(H2O)16][Co(H2O)4(HP2Mo5O23)2] with a sandglass-like shape was synthesized and characterized by means of single-crystal X-ray diffraction, powder X-ray diffraction(PXRD), infrared spectroscopy(IR), thermogravimetry/differential scanning calorimetry(TG/DSC), ultraviolet- visible spectroscopy(UV-Vis) and cyclic voltammogram(CV). Single-crystal X-ray diffraction analysis reveals that the asymmetric unit of compound 1 consists of a half cobalt ion, one {P2Mo5O23}6– anion, two coordinated water molecules and eight lattice water molecules. It is especially intriguing to note that two {P2Mo5O23}6– clusters are symmetrical about the Co ion, like a sandglass. And a chair-like water cluster with an unprecedented centrosymmetric [H8(H2O)16]8+ can be observed in compound 1. Additionally, the electrochemical and catalytic properties of compound 1 were also investigated.