Two isopolytungstate compounds based on rare [W6O22]8− and [H2W12O42]10− fragments captured by premade copper(ii) complexes†
Abstract
Two new isopolytungstate compounds, namely [Cu4(2,2′-bipy)4(H2O)2(W6O22)]·4H2O (1) and [Cu(en)2Na8(H2O)28(H2W12O42)]·4H2O (2) (2,2′-bipy = 2,2′-bipyridine, en = 1,2-ethylenediamine), were synthesized under hydrothermal conditions and in aqueous solution, respectively, and characterized by single-crystal X-ray diffraction, elemental analyses and FT-IR spectra. In compound 1, there is a rare hexatungstate anion [W6O22]8−, which is firstly captured by copper(II) complexes under hydrothermal condition by using sodium tungstate. The [W6O22]8− cluster is covered by two [Cu(2,2′-bipy)]2+ and two [Cu(H2O)(2,2′-bipy)]2+ clusters to form a tetra-supporting anion. In compound 2, the paradodecatungstate anion [H2W12O42]10− was captured by [Cu(en)2]2+ clusters in aqueous solution. The [H2W12O42]10− anions are linked by [Na3(H2O)10]3+ and [Na2(H2O)8]2+ clusters to construct an inorganic layer. The [Cu(en)2]2+ clusters connect these inorganic layers to build a 3D framework of 2. We studied the electrochemical and photocatalytic properties of these compounds.