Synthesis, structure and characterization of three highly-connected 3D inorganic compounds based on paradodecatungstate-B

Three new compounds with 3D open frameworks based on paradodecatungstate-B, [{Na(H2O)5}2{Mn(H2O)3}2{Mn(H2O)4}2(H2W12O42)]·6H2O (1), [{Na(H2O)5}2{Co(H2O)3}2{Co(H2O)4}2(H2W12O42)]·8H2O (2) and [{Na2(μ-H2O)2(H2O)6}{Cu(H2O)2} {Cu(H2O)4}2{Cu2(μ-OH)2(H2O)6}(H2W12O42)]·10H2O (3), have been synthesized and characterized by IR spectroscopy, UV–vis spectroscopy, elemental analysis, X-ray powder diffraction, thermogravimetric analysis and single-crystal X-ray diffraction. Compounds 1 and 2 are isomorphic and have such a structure that [H2W12O42]10− unit is surrounded by eight transition metal ions (Co ions for 1 and Mn ions for 2) and two sodium ions, each transition metal ion combines two [H2W12O42]10− units, forming a 3D framework with tunnels in which lattice water molecules and sodium ions reside. In 3 the [H2W12O42]10− unit links two binuclear sodium groups, two binuclear copper(II) groups and six mononuclear copper atoms, generating a complicated 3D network. Compound 2 exhibits weak antiferromagnetic interaction and the electrochemical properties of 1 and 2 have also been studied.