Preparation, crystal structure, and characterization of an inorganic-organic hybrid polyoxoniobate [Cu(en)2]3[Cu(en)2(H2O)]1·5[K0·5Nb24O72H14·5]2·25H2O

An inorganic-organic hybrid polyoxoniobate compound [Cu(en)2]3[Cu(en)2(H2O)]1·5 [K0·5Nb24O72H14·5]2·25H2O (1) was synthesized by reaction of K7HNb6O19·13H2O, Cu(CH3COOH)2·H2O and en (ethylenediamine) in aqueous solution and characterized by IR, ESR spectroscopy and single-crystal X-ray diffraction method. Structure analysis indicates that compound 1 consists of a new type polyoxoniobate anion [K0·5Nb24O72H14·5]9−, three [Cu(en)2]2+, one point five [Cu(en)2(H2O)]2+, and two point two five crystal water molecules. The structure contains N-H⋯O hydrogen bonds between the coordinated ethylenediamine and the polyniobate-anion. The whole molecule possesses the C3v symmetry.