Two-dimensional layer architecture assembled by Keggin polyoxotungstate, Cu(II)–EDTA complex and sodium linker: Synthesis, crystal structures, and magnetic properties

Reaction of Keggin polyoxotungstate with copper(II)–EDTA (EDTA=ethylenediamine tetraacetate) complex under mild conditions led to the formation of hybrid inorganic–organic compounds Na4(OH)[(Cu2EDTA)PW12O40]·17H2O (1) and Na4[(Cu2EDTA)SiW12O40]·19H2O (2). The single-crystal X-ray diffraction analyses reveal their two structural features: (1) one-dimensional chain structure consisting of Keggin polyoxotungstate and copper(II)–EDTA complex; (2) Two-dimensional layer architecture assembled by the one-dimensional chain structure and sodium linker. The results of magnetic measurements in the temperature range 300–2 K indicated the existence of ferromagnetic exchange interactions between the CuII ions for both compounds. In addition, TGA analysis, IR spectra, and electrochemical properties were also investigated to well characterize these two compounds.