Self-assembly of a nanoscale penta-cerium(III)-bridged selenotungstate: Synthesis, crystal structure and properties

Abstract

The reaction of sodium tungstate, sodium selenite, and cerium nitrate under reasonably acidic water solution in the presence of morpholine gives rise to a penta-CeIII-bridged polyoxotungstate, Na10(C4H10NO)10[Ce5Se4.75W34O128(OH)2(H2O)14]·21H2O (1), which is a rare example of selenotungstate featuring novel Keggin {SeW8} building blocks. This cluster is fully characterized by single crystal X-ray diffraction, elemental analyses, powder X-ray diffraction (PXRD), infrared spectrum (IR), ultraviolet–visible spectroscopy (UV/Vis), thermogravimetric/differential thermal analysis (TG-DTA), X-ray photoelectron spectroscopy (XPS) and electrospray ionization mass spectrometry (ESI-MS). Single-crystal X-ray diffraction analysis reveals that four {SeW8} are bridged by multi-Ce linkers and two equal “trans”-{WO6} centers resulting in this tetramer. The utilization of Ce cations and SeIVO32− heteroanion template as well as some determined assembly rules during the synthesis play important roles in the formation of 1. Additionally, its solution stability and electrochemical performance were also discussed in detail.